BIOL316 FINAL

Habitat issues: Lakes

- Deforestation of lake basins raises temperature turbidity and organic input. - Draining and filling of marshes and isolation of wetlands can have impacts on lakes as well because these are often found in close proximity to lakes and have an important role in filtering water and maintaining temperatures of water running into the lake. - blockage of tributary streams - dredging of harbours & channels

Habitat issues: Rivers and Streams

- Deforestation of the basin - Heavy logging near streams causes an increase in stream temperatures - Lack of appropriate riparian buffer zones (Riparian zones = the terrestrial borders immediately adjacent to rivers & streams) - Grazing within the riparian zone (cows) - Increased turbidity & sediment (Increased sediment can destroy spawning areas for many species (eg salmonids)) - Channelization Ecological functions of riparian buffer zones: - Intercept sediments - Reduce streambank and channel erosion - Process nutrients and contaminants (slow or prevent their movement into streams) - Control the range and elevation of stream temperatures - Provide inputs of habitat and food (large woody debris, leaves, insects) - Tree roots also provide stability to the bank Channelization = removing natural bends in streams and rivers and turning them into something with uniform depth, no twists and turns etc. This typically eliminates deep pools and other areas where fish find refuge during high temperature events, hide and wait for food etc). This is often done for navigation purposes, or to reduce the chance of flooding.

Surplus production background

- In order to manage a population effectively, we need to understand population dynamics (basic ecology) - Central problem: How do we produce the greatest crop (yield) without endangering the resource? - fisheries biology is an area where there has been a great deal of work done on the problem of optimum harvesting - this is because of the tremendous economic value of marine fisheries and the fact that we have been clearly overfishing many ocean fish populations. Thus, this area has received a great deal of attention. - in recent years, recreational fisheries have also received a lot of attention in this area, as we have started to recognize their economic importance and are trying to improve the quality of many "overfished" recreational fisheries. - one of the most important units of measure in this area is "yield" (similar to crop size in agriculture). The yield is typically expressed in numbers or weight (biomass) per unit time -what we are trying to find is the best crop or optimum yield. • For many years, maximum sustainable yield (MSY) has been considered the optimum yield • We now recognize that MSY is not sufficiently precautionary and that the optimum yield needs to be less than MSY • To understand surplus production, we will still discuss MSY

Future changes to commercial fisheries (for conservation)

- Small scale • (no avoiding this - reduce fleet size) - Remove strong selective pressures for size - Based on scientifically determined harvest quotas that are precautionary • (take into account uncertainty) - Incentives or legislation to eliminate technology that destroys habitat (eg trawling) - More selective & less (dead) bycatch Can we really get there? How? - We've already started... - Seafood labels on everything to facilitate "wise" choices - Greater public awareness about these choices - More competition from seafood obtained by sustainable practices - Increased contribution from aquaculture - Fish are the last wild animals we harvest to feed the world - this will have to change - not sustainable.

History of the Science Associated with Marine Fisheries

- Towards the end of the 1800's, the rapid increase in fishing power was also associated with new arguments over the possibility of too much fishing or "overfishing" - These arguments started amongst fishermen who were often jealous of new techniques but then spilled into the scientific community. - Initially, one of the biggest problems was a complete lack of data. - Newly created fisheries agencies from several countries (Scotland, Norway, Russia and the US) began to try and remedy this problem. - In 1885, the fisheries board of Scotland started collecting fishery statistics and conducting experimental trawl surveys to compare areas open and closed to fishing to try and determine the impacts of fishing. -In 1900, a scientist named Walter Garstang published a paper titled "The Impoverishment of the Sea" in which he showed that fishing could reduce the abundance of fishes. In this paper, he also reported that fishing one species could indirectly result in an increase in another. Using fishery statistics from the port of Grimsby, he also showed that the catch of fish per vessel had decreased by 33% between 1885 and 1895, while fishing intensity increased by 150%. - In 1902, a new intergovernmental marine scientific organization was formed called the International Council for the Exploration of the Sea (ICES). Part of the initial mandate of ICES was to promote and improve fisheries through international agreements. The mandate was also expanded early on to include studying fish growth and maturity, migration patterns, abundance and reproduction. This was the background for an ambitious research program started by ICES fishery scientists. - One of the early issues they were focusing on was the status of the North Sea plaice. By 1913, they were convinced that some sort of overfishing was occurring with this species. -Interestingly, before they could put anything in place to deal with this problem, the First World War began. This caused a drastic reduction in fishing activity that became known as the Great Fishing Experiment. - When the war ended and scientists pulled together catch data from before and after the war, the results were striking. - the war, the results showed that the weight of fish in the largest size category had increased by 500%! - the conclusion from the "Great Fishing Experiment" was that fish populations can recover when fishing is reduced. Graham's Great Law of Fishing (Graham 1943): There is a recurring pattern that plays out in many different fisheries. Catches do not continue to increase in proportion to the amount of fishing. Eventually, further increases in fishing result in smaller catches. To maintain their income, fishers invest in better equipment, increasing their fishing power to catch more. Eventually, fishing intensity reaches a level beyond which catches no longer increase and even decline. -Hulme et al (1947) used a simple mathematical model to show that fishing harder could eventually result in lower catches. - -1956 - Beverton and Holt suggest that fisheries management should adjust fishing activity to obtain the "best results"-Best results = maximum sustainable yield (MSY). This "biologically-based" objective dominated thinking in fisheries science for a long time. Where we are now... -We now realize that these early views about achieving the highest possible catch (MSY) are no longer appropriate because they were not sufficiently "precautionary". -The modern objective in resource management is "sustainable development". Sustainable Development - We should not destroy or diminish fish stocks to such a degree that future generations would not have the opportunity to gain a living from them or to benefit from the maintenance of biodiversity (Hart & Reynolds, 2002).

Key concepts of surplus production

- We can use another figure (see next slide) showing the hypothetical relationships between catch rate, biomass and fishing mortality to further illustrate some key concepts associated with surplus production models. -this figure shows how catch rate (yield) and biomass of the stock depend on the fishing mortality rate. -this figure also shows how the optimum yield occurs at a point with a lower fishing mortality rate, lower catch rate and higher population size (biomass) than the point where MSY occurs. (figure in lecture 14)

Early Science and Management

- early scientific activities in NA (1800's) consisted of describing and cataloguing the species - establishing authority for managing inland fisheries was difficult in the early years of Canada and the USA - In 1868, the Canadian Confederation passed the Federal Fisheries Act to create a Department of Marine and Fisheries. The Federal Fisheries Act included the following... --> a mandate to appoint federal fisheries officers -creation of fishing licenses --> closed seasons for some species-safe passage for some species --> free passage of fish on Sundays and prohibition of Sunday fishing! --> the Act also prohibited pollution in waters frequented by fish -Interestingly, there was recently a big controversy over changes to the Federal Fisheries Act. In 2012, the Harper government made changes to the Act and there was a backlash from a lot of scientists about it. Instead of protecting fish habitat for all fish, the Act was changed to that it states that it only protects habitat where there are fisheries (of commercial or recreational importance, so not all fish species). This seems like a subtle change, but it is actually very important. The intent and exact consequences of changes like this to the Act were hotly debated for several years after this change. A very good reference on the potential consequences of the Conservative's changes to the Fisheries Act: Hutchings, JA & JR Post. 2013. Gutting Canada's Fisheries Act: No Fishery, No Fish Habitat Protection. Fisheries 38(11): 497-501. -->Notably, the Liberal government restored the Fisheries Act to something much more similar to its' original form. For more details on this, here are some links... https://www.theglobeandmail.com/news/politics/ottawa-notebook/dont-gut-fisheries- actscientists-urge-harper/article536309/ https://www.canada.ca/en/fisheries-oceans/news/2019/06/the-modernized-fisheries-act-billc- 68-passes-parliament.html https://nationalpost.com/news/politics/fisheries-act-changes-welcomed-by-scientists- whileindustry-groups-say-theyll-wait-and-see -In 1885, the Ontario Fisheries Act was passed. This provided provincial administration (fisheries officers, licences, closed seasons and limits) over inland fisheries under the Department of Crown Lands (this was the start of the roles that are now within the Ontario Ministry of Natural Resources and Forestry - OMNRF). -In the USA, a Federal Mandate for fisheries management began in 1871 when the US Congress authorized the US Commission on Fish and Fisheries (Fish Commission) in response to the decline in fisheries. -The primary mission of the Fish Commission was to determine the reasons for declines in fisheries in New England and the Great Lakes and to develop methods of fish culture. -Descriptive surveys of fishes, habitats and pollution were conducted by many state agencies during the 1920s and 30s - mostly with the goal of understanding how and where to stock fish. -In 1938, the American Fisheries Society helped establish the first North American Fish Policy that was subsequently embraced by states and provinces. The policy outlined the roles of state, provincial and national governments in terms of fisheries, the role of research and the need for management. The document also outlined the "objectives for fisheries research", which included guidance for lake and stream surveys, fisheries statistics and other standard practices.

Fish can lose habitat when...

- it dries up or floods at inappropriate times - it fills with sediment - it is choked with vegetation or filled with debris - it is contaminated with toxicants - it becomes unlivable due to eutrophication or deoxygenation - it is destroyed or homogenized through structural damage or removal Habitat alteration is also one of the most important factors contributing to the decline of native species of fish (the fish biodiversity crisis)

Genetic effects of hatcheries on wild fish

- there are also several concerns regarding the genetic effects of hatchery practices. -there is the potential for "domestication selection" within hatchery populations. -there are also important questions about how stocking might impact the genetic diversity of wild stocks. -Some studies have now shown that hatchery practices have to potential to cause the genetic composition of hatchery populations to change drastically relative to wild populations. -this may be due natural selection within the hatchery environment for fish that are most suitable to hatchery rearing. -there is also a relaxation of selection that would otherwise occur in the wild. In the wild, early life stages exhibit extremely high mortality, but this is not the case within hatcheries. In contrast, survival from the juvenile to adult stage is believed to be much higher for wild fish compared hatchery fish (once they are released into the wild). Effects on genetic makeup of wild populations: --> natural populations show genetic compositions that are unique to their locations. --> these differences are often adaptive. --> this uniqueness can be disturbed with the introduction of hatchery fish. --> spawning of hatchery fish with wild fish can have a number of negative consequences. These include the production of inferior offspring and dilution of local adaptation. The situation is worsened when hatchery stock comes from another population (stock). --> there may also be indirect effects of hatchery fish on the genetic diversity of wild fish. -indirect effects include 1) removal of broodstock from wild populations (can be important when wild populations are small) 2) hatchery spawners may exclude wild fish from breeding grounds and 3) increased harvest of both hatchery and wild fish due to apparent increases in population size caused by the addition of hatchery fish - can result in an even smaller number of wild fish. - In summary, the introduction of hatchery fish to ecosystems can result in an overall loss of genetic diversity in wild populations. - All of this research led to debates about whether hatcheries were really effective. It was recognized that the answer to this question really depended on the definition of success. - Hatcheries had become very effective at producing large numbers of fish. However, these fish may be having a number of negative impacts on wild fish. - Despite the fact that some of the large salmon rivers in the US have multiple hatcheries producing hundreds of thousands of fish for stocking, runs of wild and hatchery fish had continued to decline. As discussed in the film seen in class, the real problem for these runs was habitat loss caused by the construction of numerous hydro dams. - A great case study in this area is the Columbia River system in the US. Depending on how you count them, the Columbia River system includes more than one hundred dams!

Modern recreational fisheries

-Based on the principle of "sustainable use" of resources -Recognition by anglers and managers that resources are "limited" -Management is based on much better science, assessment and experience. -"Selective harvest" is now widely accepted and a central component in management and the culture of angling. -Many of today's recreational fisheries are sustainable. -In situations where this is not the case, the problems are usually not a direct result of the recreational fishery. Economic Impact: - the economic impact of recreational fisheries in North America is surprising and is greater than commercial fisheries and aquaculture. Conservation Impact: - Although it is not widely understood by the general public, anglers also play a very important role in the conservation of aquatic species & their ecosystems. -Money spent by anglers on equipment, fishing licences and donations to conservation organizations ultimately benefits not only sportfish, but also other species and entire aquatic ecosystems. - All of the revenue that anglers spend on licences in Ontario goes back into the resource and funds things like research, monitoring (assessment programs), stocking & enforcement. - Many anglers also have memberships in non-government organizations that are focused on conserving fish and their aquatic environments. Trout Unlimited is a good example of one of these NGO's. - Volunteer efforts are an important contribution of many of these organizations. Trout Unlimited volunteers contribute more than 700,000 hours each year to protecting, reconnecting and restoring North America's trout and salmon fisheries. - There are many different ways to get into fisheries careers and these organizations often have full time and part time jobs, as well as training opportunities for students. - Many conservation organizations have also created programs for youth, including summer camps. These programs not only expose youth to angling, but also teach them about aquatic ecosystems and conservation. - The Atlantic Salmon Federation is another example of an important organization whose mission is to protect fish and their aquatic ecosystems. In recent years, the Atlantic Salmon Federation has played a very important role in removing obsolete dams on North American rivers. - Canada, like many other countries in the world, is becoming much more urbanized. With fewer people living close to nature in rural areas, degradation of wild ecosystems, and especially of aquatic environments, could easily go unnoticed. - Another important contribution that anglers make towards aquatic conservation is to act as sentinels for aquatic environments. Although one of their primary motivations isto catch fish, anglers are often the first ones to notice when there is a problem with fish populations, and the first to speak out about it. Anglers are often the 'conservation voice' for aquatic species and ecosystems. - Positive fishing experiences enhance someone's appreciation for fisheries and aquatic resources. This connection is similar to a 'Virtual Spiral' that actually grows stronger with each turn. Ultimately, this combination leads to a much greater willingness to conserve fisheries and aquatic resources. Reading: *Tufts BL, J Holden, and M DeMille. 2015. Benefits arising from sustainable use of North America's fishery resources: economic and conservation impacts of recreational angling. International Journal of Environmental Studies. 72(5): 850-868. *This article will be provided in OnQ

Physiology: Temperature

-Fish are ectotherms - their body temperature is determined by that of the environment -Because of this, temperature has an important impact on many physiological & biochemical processes in fish - We have already talked about the important effect of temperature on growth rate... (see Growth Lect) -In most species, temperature affects metabolic rate in much the same way. -In general, metabolic rate increases when temperature increases (and decreases when temp decreases) -interestingly, oxygen solubility in water actually decreases as temperatures increases. So, at high temperatures, there can be less oxygen available in the water even though the oxygen demand (metabolic rate) of fish is higher. At extremely high temperatures, fish typically reduce activity levels to avoid further increases in oxygen requirements. -Over time, there may be some degree of compensation when environmental (and body) temperature changes (depends on species) Important Concepts related to Temperature Tolerance: --> Each species has a window of temperature where they functions best in terms of growth, metabolism etc. These are known as "preferred temperature ranges" or "optimal" temperatures. --> Each species also has an upper and lower lethal temperature which it can survive within. Preferred temperatures, as well as upper and lower lethal temperatures can change with different life history stages. -see diags associated with these notes that illustrate what is meant by these terms. --> Temperature is one of the most important factors determining the geographical distribution of species. --> Climate change will have a profound impact on the geographical distribution of fish. Good recent review paper on this issue: Poesch et al. (2016). Climate Change Impacts on Freshwater Fishes: A Canadian perspective. Fisheries 41 (7): 385-391. Applied aquaculture issue: What temperature is best to grow a given species at? One advantage of inland (recirculating) systems is that fish can be grown at their optimum temperature for growth year round. This will greatly reduce time to market size.

Physiology: osmoregulation

-Fish are found in environments that range from very dilute freshwater to extremely concentrated salt water -In most cases, there are large gradients for salt and water between the fish and the environment -The thin membrane within the gills also provides a route for ion and water movements - Like all animals, fish must maintain an appropriate composition of extracellular and intracellular fluids in their bodies - In general, kidneys in fish are less developed compared to terrestrial vertebrates. - In contrast to terrestrial vertebrates, the gills are the main site for osmoregulation Osmoregulatory Challenges: Freshwater Fish - the ionic composition of the body fluids is higher than that in the surrounding water. Water tends to diffuse into the fish and salts diffuse out. Saltwater fish - the ionic composition of the body fluids is lower than that in the surrounding water. Water tends to diffuse out of the fish and salts diffuse in. Osmoregulatory Solutions: Freshwater teleost fish - the kidneys produce large amounts of dilute urine and specialized gill cells (chloride cells) actively take up salt from the environment Saltwater teleost fish - drink seawater, kidneys excrete very little water and specialized gill cells excrete excess salt back into the environment -It is interesting that anadromous species (and catadromous species) need to completely adjust their osmoregulatory strategy and apparatus when they move between SW and FW or vice versa. -The effects of pollution such as heavy metals, on gill ion transport function has been a very important area in aquatic toxicology.

Fisheries science vs. management

-Fisheries science and fisheries management are not the same thing. -"fisheries science is a multidisciplinary subject that integrates animal behaviour, ecology and population dynamics with environmental processes to predict how animal (fish) populations respond to fishing mortality" (Hart & Reynolds, 2002). -the results of fisheries science inform management. -management then implements policies to meet the objectives of stakeholders, including fishers, consumers, conservation groups etc. -different types of fisheries include 1) commercial 2) recreational 3) artisanal/subsistence (small scale) and 4) native (eg First Nations). - "fisheries" include fish and fishers. -An interesting view of fisheries management is that it is not about biology, but about the behaviour of fishers.-ocean (marine) fisheries tend to be dominated by commercial fisheries, although in recent years, recreational fishing in inshore marine areas has become a lot more popular. -inland (freshwater) fisheries tend to be dominated by recreational fisheries, although there are still some significant inland commercial fisheries in areas such as the Great Lakes.

History of inland fisheries in North America: Late 1900's

-Growing demands on natural resources by increasing human population -Many issues had become more complex -The tools in science and management have also evolved & become much more sophisticated as our understanding of fisheries has grown. -Fish stocks in many inland waters such as the Great Lakes have changed due to species introductions, trophic changes & pollution. -Human alterations of habitat, pollution and species introductions have led to restructured habitats and altered ecosystem dynamics. -Over 200 non-indigenous species have been stocked in the waters of North America (many in the early years of fish culture described above).

Recreational fisheries: the past

-Historically, the philosophy in recreational angling was similar in many ways to that in commercial fishing. -the goal was typically to catch and keep most, if not all, of the catch. -Another goal was to catch and keep the largest fish. Several important factors reduced the overall impact on fish populations: -Pristine Habitats - Remote locations --> difficult to access (still the case in some areas of North America) -Fewer anglers --> less pressure overall -Less sophisticated equipment (no 4 x 4's, ATV's, snowmobiles, boats without electronics etc). 1900's: - Improvements in access (roads, vehicles) -Greater fishing pressure (more anglers) -Better equipment (eg boats, motors, electronics) -Less high quality habitat -Less knowledge about science & management of fisheries (many misguided views about stocking) -Recreational angling & other factors (eg habitat loss) had substantial impacts on some fish populations. Catch and Release: -In the late 1900's, "catch and release" (releasing fish alive after they were caught) also started to become a more common practice in some recreational fisheries. -This was a very important transition in the management and culture of recreational fisheries. -This also became one of the most important differences between commercial and modern recreational fisheries. In recreational fisheries, anglers catch one fish at a time and can "choose" which fish to harvest and which to release. -In many commercial fisheries, large numbers of fish are caught at the same time and the bycatch (unintended catch) is often dead or dying by the time it is sorted. -The combination of "catch and release" and "selective harvest" provided an important foundation for sustainability in modern recreational fisheries.

History of inland fisheries in North America: Where we are today

-In recent years, there has been a much greater awareness about environmental issues and an increase in legislation that reflects this. -We are now in a period of major restoration and mitigation programs in an attempt to restore many aquatic ecosystems... -Inland fisheries have shifted from an emphasis on commercial harvest to recreational angling -Inland commercial and recreational fisheries are very well managed- Many can be viewed as "sustainable"- Today's problems in inland fisheries are usually associated with habitat and invasive species, rather than overharvest. Interesting Links: Trout Unlimited Canada https://tucanada.org/ Ontario's Bring Back the Salmon Program http://www.bringbackthesalmon.ca/about/ Ontario's Provincial Fish Strategy https://dr6j45jk9xcmk.cloudfront.net/documents/4538/ontarios-provincial-fish-strategy.pd

History of Marine Fisheries

-Many of the early fishing vessels (1700's & 1800's) were powered by wind and used long lining as a technique to catch fish. -One of the most significant early developments in fishing was the adoption of steam power in the late 1800's. -this was followed by changes in gear because the more consistent pulling power of the new steam powered vessels allowed the vessels to start using new larger trawling techniques (otter trawls) instead of using long lining or smaller trawls (beam trawls). -the new trawling methods were much more efficient. -in addition to the new methods, boats starting going farther and farther afield to catch fish as they competed against one another for the biggest catches. -this kind of expansion is common in fisheries and is also driven by declining catch rates in closer areas. -in the early part of the 20th century, there were many other advances in fishing techniques and gear. -boats shifted from steam power to diesel engines and some vessels started processing their catch on board. -in the 1950's hydraulic winches began to be used. -after the second world war, echo location (sonar) equipment also became more readily available allowing fisherman to find the fish before setting the gear (much more efficient). -some of the other big developments that changed the face of the fishing industry were related to processing. -methods of preserving fish such as canning allowed fish to be preserved and shipped to far away markets. -We now have factory trawlers that can catch and then process huge catches on board.

History of inland fisheries in North America: before European settlement

-Native Americans exploited fisheries resources of North America prior to settlement by Europeans, and in many regions, fish were central to the culture and economy of aboriginal inhabitants.-Pacific salmon provided food resources for native peoples from north-western California to Alaska along the Pacific coast. The salmon runs were often a central element in native culture. -fish was also a staple food for many tribes in the Great Lakes region. -Despite the importance of fish in areas such as the Pacific coast and Great Lakes region, there was little evidence that Native American fisheries exceeded sustainable levels.-the available evidence suggests that Native Americans were capable of overexploiting fish populations, but social and cultural traditions tempered harvests and maintained sustainability. -European immigrants encountered fisheries resources in essentially an unexploited state, but brought a value system that necessitated a more formal system of fisheries management. -Prior to large scale immigration of Europeans to North America, European travelers sent back incredible tales of the richness of fisheries resources in NA. -"rivers so full of salmon, you couldn't walk across them without touching the fish", "travelers unable to sleep at night because of the noise of salmon jumping" etc...-"net hauls from lakes so large that teams of horses were required to land the catch"... -European immigrants brought a philosophy that natural resources were a fuel for economic development. -this view changed the nature of the continents aquatic resources

Physiology: Nitrogenous (Metabolic) Wastes

-Nitrogenous (metabolic) wastes in animals can be in the form of ammonia, urea or uric acid. -In most fish species, ammonia is the principal nitrogenous waste -Ammonia is highly toxic an must not be allowed to build up in the body -Fish excrete ammonia into the surrounding water via gills and kidneys Applied Issues: -Osmoregulation and nitrogenous waste excretion are important issues for inland (recirculating) aquaculture. -researchers have been experimenting with different environmental salinities to determine whether there could be an energy savings by reducing the cost of osmoregulation that could be put into growth. -it is well known that ammonia levels must be kept low in recirculation systems, or there will be problems. Interestingly, however, relatively recent research has shown that some low level of ammonia may actually benefit growth in some species of fish (so it may actually be better if it is not completely removed). -Once again, there are many linkages for all of these topics between basic (fundamental) biology of fish and applied "fisheries" issues. -Interestingly, aquaponics systems that take advantage of nitrogenous wastes from fish to grow plants (without soil!) are becoming much more common. If you are interested, you will have an opportunity to view our demonstration project in this area at the end of term.

The Problem of Uncertainty

-One of the biggest challenges for the future is to devise institutional systems that are able to take "uncertainty" into account and make appropriate decisions with this in mind. -A big reason behind the collapse of some major fisheries is that uncertainty about their state was either ignored or played down. - A prime example close to home is what happened to the cod fishery. In a nutshell, this is what happened to that fishery... -conflicting evidence was available to the Canadian Department of Fisheries and Oceans about the state of the cod stocks in the 1980's .-catch per unit effort (CUPE) from the commercial fishery remained high and indicated an expanded stock. -DFO's own survey data showed that the stock was at a steady level. -Data from the inshore fishery sector showed a decline since the 1970's, but these data were ignored. -It should have been recognized that there was "uncertainty" about the status of the cod population, but catch quotas continued to be set at a high level and the stock collapsed. -If you think about what you've just learned about the sonar in modern commercial trawlers, the commercial catch probably remained high because the modern electronics were able to locate any remaining groups of fish until they were gone.

History of inland fisheries in North America: 1800's and early 1900's

-Period of massive harvest. -Development of canning and freezing technology increased the demand for fish that could now be preserved and transported long distances to markets. -Period of large commercial inland fisheries. -Also destruction of habitat from timber removal, mining, industrial development and introduced species. -The last record of Atlantic salmon in Lake Ontario was in 1897.-Use of cultured fish (hatcheries) was seen as a way to rehabilitate degraded fisheries. -Newly developed railroads provided access to waters for stocking fish. -Non-game & non-commercial fish were considered rough or trash fish & removed to enhance more desirable fish. -Many dams were constructed during this period on major rivers for power, flood control, irrigation etc (with little concern for environmental impact and fish passage)

Questions about potential negative impacts of stocked hatchery fish on wild populations:

1) How do hatcheries impact wild fish and aquatic ecosystems? 2) Have hatcheries been successful at achieving their goals? 3) Are hatcheries sustainable? In association with the debates on these issues, the last 30 years or so has included a lot of research examining the differences between hatchery (stocked) fish and wild fish and the potential impacts of stocked fish on wild fish populations...

Major causes of declines of native fish species

1) Physical habitat alteration 2) Competition and predation from introduced species 3) Hybridization (breakdown of reproductive barriers) 4) Chemical alteration, contamination or pollution of water 5) Overharvesting (over exploitation) * some people would group #4 into #1 Interestingly, recreational anglers are often the most vocal advocates helping to maintain freshwater aquatic habitats.

Objectives of aquatic reserves

According to a paper by Jones (Rev. Fish Biol. Fisheries, 2002), the main objectives of aquatic reserves are as follows: -Protect rare species and/or habitats -Conserve representative habitats -Promote research and education -Create harvest refugia -Control tourism and recreation -Maintain aesthetic & traditional values Are reserves successful? This is an ongoing issue. --> According to Halpern 2003, a survey of 89 reserves (ranging in size from 0.002 to 846 km2), showed benefits at several different trophic levels, including planktivorous fish, carnivorous fish and invertebrates. There are also examples of successful reserves in freshwater. Reserves have played an important role in rehabilitation of lake trout populations in Lake Superior More science is needed! In general, there is still a lot of science that needs to be carried out on this topic. This should not be a reason "not to act" to create more protected areas, but it is clear that science will need to play a big role in determining the best way to use this mechanism to protect different species. Science will also be needed to assess how well things are working when MPA's are created and to suggest ways to improve if the objectives are not being met.

Why is managing the fishery important?

After an appropriate target level of harvest has been determined by surplus production models, the role of fisheries managers is to implement that target for the fishery (see slide "Putting Things in Context"). Depending on the type of fishery, this may involve different approaches and management options. This lecture discusses the different approaches that are used to regulate harvest in different fisheries. Management options used to solve the issue of how do we achieve the target level for harvest? The best place to begin this discussion is to re-visit the graph and equation for the simple logistic-type surplus production model. In this equation, the term "qXN" is represents the mortality from fishing (F), where q = catchability (a constant), X = fishing effort and N = population size. qXN = F (total mortality from fishing) where: q = catchability X = fishing effort N = population size In most commercial fisheries, the harvest target (ideal fishing mortality, F or "qXN") would be determined by a surplus production model and then set as a quota (total allowable catch, TAC) typically in biomass (tonnes). Once this target for harvest is reached, the fishing would stop. An example for a safe harvest target might be something like 30 to 40% of the adults in the population, but the exact number would depend on the nature of the fishery and the results of the model.

Estuaries

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments known as ecotone. - Watershed development has increased silt load, nutrients and contaminants (SF Bay) - Dredging of channels is also an important habitat issue in estuaries (SF Bay) - Fraser River near Vancouver passes through farmland and industrial areas, picking up nutrients, silt and contaminants

Why had hatcheries persisted and become so common?

As mentioned earlier, hatcheries are appealing for a number of reasons. The use of hatcheries also avoids having to deal with the real problems such as over-harvest and habitat loss. It has been suggested that hatcheries are an addictive quick fix that doesn't require serious changes on the behalf of user groups. As a result of all this research and debate, most people recognized that many things in this area had to change. In the last 20 years, there has been a lot of re-thinking and reform in this area.

Why is fisheries assessment (How many fish/fishers there are) important?

At this point in Biology 316, you should be aware that some things have gone terribly in the world's fisheries over the past few decades. Terms such as "overfishing" & "global fisheries crisis" are widespread in the scientific literature and popular media. As you observed in the most recent documentary for this class, End of the Line, not everyone agrees about the current state of the world's fisheries. The vast majority of fisheries scientists, however, agree that there are serious problems in the way that we have used many of the world's fisheries in the past and that we need to establish better ways of doing things in the future. Going forward, the big issue is how to use these resources sustainably. More specifically, how many fish can we harvest sustainably and what are the best ways to make that happen in different fisheries. The next 3 lectures in this course are about the ways that we try and achieve sustainability in fisheries. This lecture on "fisheries assessment" describes the ways that we attempt to determine how many fish are in the population. The next lecture in this series is on a topic called "surplus production models" and will describe the principles we use to determine how many fish we can harvest sustainably. The final lecture in this 3 part series focuses on the management strategies that are used to achieve a target level of harvest in different fisheries. Issue: How many fish are in the population --> Approach: Assessment Issue: How many can we harvest sustainably --> Approach: Surplus production model Issue: How do we achieve the target level for harvest --> Management options For many different reasons, managing fisheries is a dynamic process. If you look at the diagram below, you can see that regardless of our best efforts to manage fisheries, the abundance of populations is going to change over time. For example, you know that many different factors affect recruitment in fish populations, so even without human interference, fish populations will fluctuate. For any give abundance, we set targets for harvest, which is the yellow bar in this figure, and ideally, we keep monitoring the population over time. If abundance drops too far below our targets, regulation changes can be put in place to try and raise abundance. If abundance rebounds and becomes considerably higher than our target, we can change regulations again to harvest more fish and bring the population down closer to our target abundance. This is a dynamic process and continues over time. (refer to figure in lecture 13) Fisheries assessment is analogous to conducting an inventory of the fishery. Sound management decisions require knowledge of both how many fish (resource) and how many fishers (resource users) compromise the fishery.

Why are marine protected areas, sanctuaries and conservation reserves important?

At this point, you should all be familiar with the major problems in the world's oceans. Many of the world's experts now believe that protecting areas of the ocean from activities like commercial fishing is the best hope to reverse many of the negative trends in the ocean environment. On the surface, this may seem like a simple solution. However, there is lots of debate around things like "what activities should we allow in these areas?" There is also a need for scientific information on issues associated with these areas. For example, how big should they be to have an impact for different species? How effective are the ones that exist now? What species do they work for and what species do they not work for? This is a very current topic... In recent years, there is a lot of interesting information pertaining to MPA's in the news and on the internet. There is also a lot of recent science in this area will be discussed at the end of this lecture. General Information --> Terrestrial reserves have been a cornerstone of terrestrial conservation for many years. --> Marine protected areas, sanctuaries and conservation reserves are a variety of terms used to describe similar protected areas in aquatic environments. --> A general definition for these areas is as follows: "Any area of littoral or sub-tidal terrain, together with its overlying water and associated flora, fauna, and historical and cultural features, which has been preserved by law or other effective means to protect part or all of the enclosed environment". Marine protected areas (MPA's) were first implemented in 1925 in Alaska and were designed originally to protect waters important to whale and seal populations. Their popularity grew in 1950's as humans began spending more time underwater with the invention of SCUBA.

marine environments

Bottom trawling is the most important habitat issues in marine environments

Evolution in Fisheries: Case Study 2

Case Study #2...Selection and Evolution in an Experimental Fish Population. (Conover and Munch. 2002. Science. 297: 94-96.) -Three laboratory populations of Atlantic Silversides (Menidia menidia) were established. -One population was selected for fast growth rate by only allowing the largest 10% of the fish to reproduce every generation. -One population was selected for slow growth rate by only allowing the smallest 10% of the fish to reproduce every generation. -The 3rd group was a control where a random 10% of the fish in the population were allowed to reproduce every year. Results -As expected, the populations responded to selection. Within only 4 generations, the fish in the group selecting for large individuals were approximately twice the average size of those in the group where there was selection for large individuals. Conclusions - This highly controlled study produced further evidence that fisheries can produce selection pressures on fish populations for slow growth rate and early age at maturity and that fish populations respond to these pressures with decreased growth rates within a relatively short time frame (surprisingly short in this case). Review Paper - Borrell, B. 2013. A big fight over little fish. Nature. Vol 493: 597-598. -Another very interesting paper on this issue was published in Nature in 2013 (Borrell 2013). -The important message in this paper was that..."For Northeast Arctic cod, the age, size and weight of first time spawners have fallen dramatically in this century"- other important points discussed in this paper include the following... -Most commercial trawlers have large mesh nets that allow younger, smaller fish to escape. This strategy selectively harvests only the fattest, oldest members of the population and let young fish survive to spawn. -These size restrictions have historically been thought to protect populations.- Fishermen have also been happy to concentrate on larger, high value fish. -But there is now a growing view amongst researchers that fish are adapting to size restrictions by investing their energy into reaching sexual maturity earlier instead of growing large. -As a result of their small size, they also produce fewer eggs. -This impact of this evolution in fisheries is compounded over time and scientists believe it will be hard to reverse. -This is a very complicated issue because it also doesn't make sense to increase pressure on juveniles. -The paper suggests that the best way to preserve fish populations is simply to fish less. -Some scientists also believe that marine reserves should not be so focused on protecting spawning grounds because it gives another advantage to early maturing fish that return first to spawn. -Another suggestion is to abandon most size limits-this is a short, but very interesting paper that brings together many things discussed in Biol 316. This paper is something you should be reading along with these notes (the reference is provided above and the paper will be provided in OnQ).

Evolution in Fisheries: Case Study 1

Case Study 1: Selection Pressures on Cod in the Gulf of St. Lawrence. (Sinclair et al. 2002. CJFAS. 59: 361-371). --> Prior to 1967 there was no minimum mesh size regulation on Atlantic cod (Gadus morhua) in the Gulf of St. Lawrence. -This meant that there was little or no selection pressure for small size. - Minimum mesh sizes were imposed in 1967, and were increased (made even smaller) in 1974, 1981. -These changes increased the selection pressure for small size.In 1993, the fishery was closed, which removed the selection pressure for small size. Methodology - Investigators had trawl surveys taken annually from 1971-1998From these, they were able to estimate size structure of the Atlantic cod population in each year. They used a technique that allowed them to back-calculate age-at-length for individual fish (see growth lecture to see how this is done). This made it possible to test whether survivors in any given year are small individuals. When selection pressure existed for smaller fish, smaller fish did indeed have higher survival. The data collected in this study clearly show how the size structure of the population shifted and the fish became smaller at a given age. Conclusion: Commercial Fisheries can impose selection pressure on size...

Evolution in Fisheries: Case Study 3

Case study #3 showed that similar things probably happen in recreational fisheries. In this situation, a study was carried out on Bluegill (Lepomis macrochirus) by Drake et al. 1997. NAJFM. 17: 496-507. -bluegill are a popular sportfish (particularly in the USA), but they are relatively small. Most of the harvest is typically directed towards large individuals because those are the fish that are big enough to eat. So, these fisheries tend to be very size selective. -this study provided evidence that intense fishing effort was associated with smaller sizes at maturity in bluegill.

Regulations in recreational fisheries

Catch and release regulations (harvest): • Increasingly popular as a management tool in recreational fisheries • Some fisheries are 100% C&R • Others may require anglers to release fishes that are specific sizes, wild stock etc • Use to balance the need to provide fishing opportunities with conservation (protect broodstock etc) Creel and Possession Limits (harvest): • Creel limits are the most common form of regulation to restrict harvest in recreational fisheries. • Creel limit = the number of fish that can be harvested by an individual in a single day • Possession limit = the number of fish that can be possessed by a person at any one time Length (slot) Limits (harvest): • Only fish of certain lengths can be harvested • Most common = minimum length (eg allows fish to reach reproductive size) • Another common strategy = only fish in a certain size range can be harvested (slot size regulations) --> In the example shown in the next slide, there is a protected slot size for medium size fish. The idea behind this type of slot is that smaller fish are thinned out when some of them are harvested (creating better foraging conditions (lower density) and growth for the remaining fish). Most of the fish that reach spawning size are then protected by the slot, therefore allowing them to spawn and contribute back to the fishery. As an incentive (often social/economic reasons) for anglers for the fishery, anglers might then be able to keep a small number (typically one) of very large fish as a trophy if they happen to catch one. The idea here is that there are few very large fish to catch and they have already contributed offspring to the fishery when they were normal (medium) size adults. --> Medium sized fish are conserved and protected against harvest Interestingly, the thinking around slot limits that allow anglers to keep one very big (trophy) fish is changing amongst managers and anglers as we learn more about the biological value of "big fish" Remember, the earlier info on "BOFFFS"...Science is indicating that these are often valuable fish for the fishery. Female fish produces eggs correlating to her body weight and get better and better as they age, and never reach their peak. In the future, there will likely be fewer regulations that allow harvest of these big fish & fewer people who want to harvest these trophy individuals There is now an entire industry around realistic "trophy fish" replicas (photos and measurements are often taken from real fish that are caught and released. Seasons (effort): • Prohibit fishing for species during defined time periods • Often used to protect fish during spawning or when they are concentrated in certain area Gear restrictions (effort and catch rate of gear): Wide array of strategies here... *some of these also affect "unintentional" mortality (another form of "h") - Two rods per angler allowed in Great Lakes (effort) - Fly Fishing Only (catch rate of gear) - Catch rate and harvest..."Single Hooks Only", "Barbless Hooks Only" Catch rate of gear (c) & "unintentional mortality (h) " Tags (harvest): - In some fisheries (eg Atlantic salmon in Canada), a limited number of harvest tags are sold to each angler who applies for them - Other variations on these themes are also sometimes used, but all can be explained as ways to manipulate the variables that affect fishing mortality (by earlier equations) - Predicting the impact of changes to harvest regulations is another area where models are used...

Catchability

Catchabillity= probability that a fish encounters the sampling gear and is subsequently captured by the gear Catchabality = p(Encounter) x p (Capture) Catchability can change based on many factors. - Encounter depends on--> Fish activity level (are the fish moving), habitat (obstructions?), Palegic vs. benthic - Capture depends on--> Gear type, mesh size, fish shape, fish size

Assessing the fishers

Commercial fisheries are typically regulated through some form of licensing and therefore managers have direct knowledge (and control) over the number of fishers operating within the fishery. Recreational fisheries tend to be open access and thus much more difficult to determine the number of people participating. An inventory of the number of recreational fishers is referred to as a creel census. Catch per unit effort (CUE) in creels is often measured as # of fish per hour of fishing time (e.g. 0.2 walleye/hour). Commercial CUE is relative to the type of gear being used (tonnes/km of gillnet or tonnes/km of trawling). Determining the amount of harvest in commercial fisheries is often to through mandatory reporting through the licensing process. To ensure or monitor compliance on board observers may be used. Several methods of surveys are conducted to assess the recreational fishery (listed in slides). Some methods such as aerial creels can only assess effort while others, such as a roving creel, can assess harvest rates. Creel censuses also collect information about anglers such as angler origin and economic factor to assist managers assess the value of the fishery.

Dams

Dams affect flows & water temperatures --> Summer fish kills can occur during high temperature events on rivers, particularly those with multiple dams and multiple stakeholder groups wanting to use the water for agriculture etc. The Klamath River fish kill in 2002 was a prime example...(68,000 salmon killed) Summer fish kills can occur during high temperature events (Klamath River 2002: 68,000 salmon killed) - Dams also cause habitat fragmentation (Image of major Ottawa River Dams: 43 total) Habitat fragmentation = the emergence of discontinuities (fragmentation) in an organisms preferred environment, causing population fragmentation. An important factor in species declines and extinctions. --> Sturgeon are classic examples of species affected by habitat fragmentation

Why is fish hatcheries and stocking important?

Every year, millions of young fish are produced in hatcheries and stocked into natural water bodies in North America. There are many different opinions on whether or not this is a good idea. The history of fish hatcheries and stocking in North America is very interesting. It is a topic that not only has lots of biology associated with it, but also sociology, economics etc. These issues were hotly debated in the 1980's and 90's and these debates still go on today. In this lecture, we will talk about the history of hatcheries and stocking and the issues behind the debates on this topic. The documentary "Salmon, Running the Gauntlet" also provides a good "real world" look at some of these issues".

What are fish hatcheries and why are they used?

Fish hatcheries are facilities that support the artificial fertilization of fish eggs and rearing of young for stocking into natural environments. Hatcheries (stocking) are commonly used to support recreational and commercial fisheries. -->There are different types of fish hatcheries - public and private. In Canada, some hatcheries are run by the Federal government (Department of Fisheries and Oceans). Others are run by provincial governments. Some hatcheries in Canada are also privately run (many by fishing clubs) --> On the positive side, hatcheries provide jobs and typically promote awareness of the fisheries resource. They often involve volunteers and frequently make efforts to educate school children about conservation and fisheries issues. --> Despite the positive attributes described above, the scientific community began to have many serious questions about hatcheries and stocking in the 1980's and 90's. These questions were also associated with a great deal of research in the last few decades to understand the differences between hatchery and wild fish and the impacts of stocking. This lecture also looks at the history behind this issue, the debates and research and where we stand today...

Fishery independent surveys

Fishery independent surveys are monitoring programs that are specifically used to assess the status of fish populations - They don't rely on information from fishers to determine the status of the population - Usually conducted with a specific objective by a government agency (e.g. DFO, OMNR)

Behavioural effects of hatcheries on wild fish

Hatcheries are designed to produce as many fish as possible. Fish are raised at very high densities and fed prepared food (fish pellets). Not surprisingly, studies have now shown that there are many important behavioural differences between wild and hatchery fish (see table below for general behavioural differences). Wild: Aggression--> low Migratory behaviour --> disperse Foraging behaviour --> efficient Anti-predator behaviour orientation --> near bottom Reaction to large moving objects --> flee Hatchery: Aggression--> high Migratory behaviour --> congregate Foraging behaviour --> inefficient Anti-predator behaviour orientation --> at surface Reaction to large moving objects --> approach - these behavioural differences likely result from hatchery conditions, selective forces or both. -many of these behavioural differences are thought to have important ecological consequences. -some of these differences in behaviour, such as anti-predator behaviour, are thought to have an important impact on survival in the wild (ie a much higher percentage of hatchery fish are eaten by predators as compared to wild fish). -it has also been shown that hatchery fish have reduced reproductive success in the wild.

Effects of hatcheries on wild fish

Hatchery fish raised using the approaches during the 1980's and 90's (traditional) differ from their wild counterparts in several respects. Many of these differences can be divided into two categories...1) behavioural and 2) genetic.

Why is history of marine fishes important?

It's only been during the past few decades that we've really begun to really understand the incredible impact that commercial fisheries have had on marine fish populations. The history of these fisheries is now extremely important. Since humans are not good at perceiving gradual changes in ecosystems, most people have no idea how much things have changed. In this regard, it is also noteworthy that we are still learning what the real baselines were for many fish populations.

Good reading on hatcheries

Kline, PA & TA Flagg. 2014. Putting the red back in Redfish Lake, 20 years of progress toward saving the Pacific Northwest's most endangered salmon population. Fisheries. Vol 39 (Issue 11): p 488-500. This article is worth looking at because it highlights how much biology (eg genetics etc) has gone into the attempt to rescue the endangered stock of Pacific salmon in Redfish Lake. It is also a good demonstration of how far our thinking has come in this area. As an added bonus, it fills in more of the story behind the film seen in class.

Physiology: Oxygen and Respiration

Life in water: - The physical and chemical characteristics of water have an important impact on the functional design of fish. - The solubility of oxygen in water is much lower (approx 1/30) that in air. - Rates of diffusion are also much lower in water compared to air. - The relative availability of oxygen is therefore much lower in water compared to air - Water also has a much higher density than air - For these reasons, fish use a very different strategy (more efficient) for respiration compared to terrestrial vertebrates - Tidal ventilation (as in mammalian lungs) is not possible for active aquatic species - energetically too costly - Unidirectional ventilation of water across the gills and a highly effective countercurrent exchange system in gills are the main strategy used to obtain O2 in fish - A few species also tap into the rich O2 supply in air using special adaptations. Aquatic hypoxia: --> In aquatic environments, there are many situations where the amount of oxygen in the water becomes much lower than normal (fully saturated) conditions (known as aquatic hypoxia) --> Eg ice covered lakes, tide pools, warm water with a lot of decaying organic material (natural or eutrophication caused by humans). --> In extreme cases, this can result in fish kills. --> In recent years, large algal blooms due to eutrophication caused by human activities are becoming more common and more serious (eg Lake Erie). Dead zones of extremely low oxygen and fish kills are just some of the problems resulting from these blooms. Applied issues: --> Any time fish are being held in captivity, oxygen levels are one of the most important issues to be concerned about... --> Some examples include... -Aquaculture situations - inland recirculating tanks with high densities of fish -Live Release bass tournaments using Live release boats with high densities of fish -Fish transport (aquarium trade etc), fish stocking situations (eg trucking fish) Interesting Case Study: (combined oxygen and temperature issues) Reference: Guzzo, MM and PJ Blanchfield. (2017). Climate change alters the quantity and phenology of habitat for Lake Trout. Can J Fish Aquat. Sci 74: 871-884. Major finding: Climate change is reducing the habitat available for Lake Trout in summer due to constraints imposed by oxygen and temperature.

Problems and Challenges with Reserves

Mobility: - Sedentary species and low dispersal abilities need small reserves - Species with high dispersal abilities are not enclosable (e.g., swordfish) - Many species are in-between. Size: Principles of reserve design are: -Representation - all habitats need to be represented -Replication - represent all habitats multiple times -Network : multiple reserves (to accommodate fish movements and to create redundancy) -Need to protect 20-30% of total habitat area (minimum) - maybe more? Assessment -The majority of reserves have not been assessed according to their management objectives. Assessment information needs to be collected. A new way of thinking: Many people believe that the primary causes of fisheries management failures have been related to the single species approach and uncertainty in stock assessments used to determine the allowable catch. As a result, management actions are often inadequate or too late. Reserves represent a change in attitude towards novel management techniques. MPA's are a more Precautionary Approach In recent years, there has been a lot more discussion about more "precautionary" approaches to management. This has also resulted in a term that is now being used a lot, which is the precautionary principle. --> Precautionary Principle (def): Stringent management actions taken first, and relaxed later if research demonstrates it is not necessary. This principle highlights uncertainty and risk and reverses the 'burden of proof' to industry or harvesters.

Where we are today re: hatcheries

Most advocates for hatcheries now agree on the following: 1) hatcheries should be used with caution 2) managers must be aware of the risks 3) hatchery programs should have clearly defined goals & their progress should be constantly evaluated against these. 4) we also need to change the way hatchery success is judged. 5) hatcheries should be used in conjunction with habitat restoration and harvest limitations when appropriate There are also new roles for hatcheries that are emerging. These include... 1) Species restoration 2) Gene banks - maintain some of the last remaining individuals of some stocks of fish 3) Creation of "put and take" fisheries to divert fishing pressure away from pressured natural populations 4) Maintenance of sport fisheries in permanently altered ecosystems (Great Lakes)

Basic ecology how most populations grow

One of the most important underlying principles about harvesting populations is to understand the basic ecology about the way that most populations grow... Most populations typically grow in a sigmoid fashion... The brief explanation for this sigmoid growth curves is as follows: Initially, the population will grow slowly in absolute size. It will then reach a maximum rate of increase near the middle of the curve and will then grow slowly again as the population nears its maximum density (carrying capacity) for that environment. Maximum growth occurs at the middle of the sigmoidal curve (time vs. population size) The amount of population increase at any given point in the sigmoid growth curve can be calculated by a simple equation: dN/dt = rN [(K - N)/K] where: N = population size t = time r = growth rate of the population K = carrying capacity (max density) If we use real values to calculate the amount of population increase (dN/dt) at different points on the sigmoid curve, we can determine where the maximum amount of population increase occurs... (SEE FIGURES IN LECTURE 14) Max growth (dN/dt) between S3 and S4 on sigmoidal curve --> So, if we are trying to obtain the maximum yield from this population, we should try and keep the population around the mid-point of the curve (S3)

Important definitions re: fisheries assessment

Open Access: any member of the public is able to participate within the fishery, often the only requirement is the purchase of a fishing license. Creel Census: the term creel refers to the historical wicker baskets that anglers used to retain their catch. A creel census may be used interchangeably with creel survey. A creel census is typically designed to provide managers with estimates of angler effort and harvest. Angler Effort: is a measure of the amount of fishing that is occurring. This may be reported as a total effort for an entire season or scaled to a unit or measure (e.g. hectare, km of stream etc). Commonly it is reported as angler days, angler hours or rod hours (esp. in fisheries where multiple lines are utilized). Catch per unit effort (CUE) : is a ratio of total catch to some unit of effort. CUE measures differ widely depending on the usage between angling, commercial catches or index assessments. Roving Creel: is a survey where managers conduct on the water interviews with anglers to obtain information about catch and harvest. Fish harvested may also be sampled for biological information such as length and aging structures (calcified structures such as scales and otoliths). Relative Abundance: a complete inventory of the fish population is rarely feasible and thus relative abundance is used as an index of abundance for populations. Relative abundance can be reported in terms of CUE of a particular type of index gear (e.g. 12 walleye/net). Relative abundance can be used to compare trends between lakes or years if the methods of sampling are comparable. Fisheries Dependent Surveys: are methods of assessing relative abundance of the fish population that depend on the fishery such as creel surveys or commercial catches. Fisheries Independent Surveys: are methods such as index netting programs that assess the relative abundance of the fish population separately (independent of) the fishery. Index Netting: are standardized netting methods (can be gillnets or trap nets) so that data collected between lakes and years is comparable. The goal of Index Netting programs is to maintain a consistent catchability ('q') between surveys. Catchability (q) - is an efficiency coefficient that describes the relationship between the number of fish caught in the gear (e.g. an index netting survey) and absolute abundance of the population. CUE=q x Population Size (e.g. density), so Pop size = CUE/q. Example: If the q was known to be 0.5 and the index gear CUE was 10 walleye/hectare, you could infer that the true population size was 20 walleye/hectare. Catchability is not always known in an index program but surveys can compare relative abundance between surveys if catchability remains constant.

Gear Types

Passive: - Gear is fixed in one location and fish movement enables capture - Weir (fishway station) - Gillnets - Live traps (trap nets, fyke nets, hoop nets) - Minnow traps Active: - Gear is moved around to capture fish - Electrofishing (boat, backpack) - Seine nets - Hydroacoustics - Trawls

Why is physiology important?

Physiologists strive to understand how animals work. Understanding how fish work is an issue that is very important in fisheries biology. For example, this understanding provides us with information about how different species will respond to changes in their environment (eg climate change). Knowing how fish work in ideal environments also helps us to understand what is going wrong in situations where things aren't working properly (eg in polluted environments). We also need a very good understanding about how fish work in order to optimize conditions for growth and reproduction aquaculture. These are just a few examples of many.

Background on evolution in fisheries

Prior to examining some case studies on this issue, it is important to point out that there is an important trade-off between growth and reproduction in fish. In some cases, fish can put more energy into growth, in which case they become larger and reproduce for the first time (age at maturity) at an older age. The other option is to put more energy into reproduction and reproduce for the first time at a younger age and smaller size. Populations of fish can potentially be pushed in either of these directions, but in theory, harvest of the larger individuals in a population should create a selection pressure that pushes the population towards a younger age at maturity and smaller size when the fish first reproduce.

Summary of Important Points Re: Reserves

Protected areas are growing as conservation tools, but there are a lot of things that still need to be done in this area. For example, they must have clearly defined goals and their effectiveness must be evaluated. They also need to represent all biogeographic zones and the appropriate size of reserves for different purposes needs to be determined. Individual reserves need to be large enough to accomplish their goals. The total area set aside for reserves also needs to be much larger than it is now if we are going to reverse the damage that has been done to aquatic ecosystems Recent Science: As is the case for news and popular press articles about MPAs, there is a great deal of recent science happening in this area. A search of the Web of Science (April 8, 2021) for scientific journal publications containing the terms "Marine Protected Areas" and "Fish" found 1,661 papers published in the last 5 years! Good Supplementary Reading on this topic: (both articles will be available in OnQ) 1. Pinheiro et al. (2019). Hope and doubt for the world's marine ecosystems. Perspectives in Ecology and Conservation 17: p 19-25. 2. Heffernan, O. Troubled Waters. Scientific American. February 2018 Issue. P 44-49.

Why are recreational fisheries important?

Recreational fisheries are associated with a lot of misconceptions. Many people who do not know a lot about fisheries tend to view recreational fisheries as another contributing factor to the global fisheries crisis. When "overfishing" and the "global fisheries crisis" are talked about in the news, it is not always clear that this is primarily a commercial fishing issue and that recreational fisheries are quite different. The history of recreational fishing contributes to this view. Some of the scientific literature in recent years has also focused on the similarities between recreational fisheries and commercial fisheries without also recognizing the important differences between them. In 2015, we published a review paper on this topic which is required reading for this lecture. In this paper, we discussed some of the important differences between modern recreational fisheries and commercial fisheries and also tried to put the economic and conservation benefits of recreational angling in a proper perspective.

Sampling the fishers

Recreational fishery: - roving creel - Access creel - Mail/phone survey - Angler diaries - Tournaments - Aerial counts Commercial Fishery: - Harvest reporting - Onboard observers * Limited access (e.g. licensing) of the commercial fishery allows for direct measures of harvest

Evolution in Fisheries Summary

So, to summarize so far...Fish populations can "evolve" in response to fishing Quantitative traits, such as size and age at first maturity can change "for the worse" -the result is typically reduced size of individuals These problems potentially affect both commercial and recreational fisheries The last part of this lecture discusses the fact that there are probably many other traits that are being selected for by commercial and recreational fisheries. For example, recent studies are showing that individuals within fish populations have different "personalities" that seem linked to their genetics. Some fish are bolder, more aggressive and have higher metabolic rates, whereas other individuals are less bold, less aggressive and have lower metabolic rates. Bold fish swim more and explore more of their surroundings (more likely to be caught in fisheries) to obtain enough food to support their higher metabolism, whereas less bold and less aggressive fish live in smaller areas (explore less) and eat less because of their lower metabolic rate (less likely to be caught). -The term for the selection that has been shown in fish populations as a result of fishing is "Fisheries-Induced Evolution". Fisheries-induced Evolution (formal definition) = A genetic change over generations in one or more characteristics of a population in response to selection imparted on individuals in that population via fishing. The last study in this lecture described a very long-term experiment that showed that fisheries-induced evolution can even occur in some catch and release recreational fisheries. This study looked at the long-term impacts of catching male bass off their nests during the parental care period when they are protecting their offspring from nest predators.Some provinces and states have an open angling season during this time whereas others try and keep the season closed until the parental care period is complete. The long-term studies described in Philipp et al (2015) explain that the best parental male bass are actually the most aggressive fish with high metabolic rates. These traits make them more successful at parental care and adding offspring to the population in the absence of angling. If regulations (or poor timing of the bass season) allow angling of these fish, however, then the genetics of these fish are slowly removed from the population because nest predators will consume the offspring of these fish (when they are angled away from the nest) more often than those of less aggressive males who are less effective at parental care and less likely to be caught by anglers. This paper is interesting reading and will be provided will be provided with the notes in OnQ

Habitat improvement projects

Some habitat improvement projects go back and try to fix the problem... - Road construction --> Road construction (roads over streams) often create areas where sediment gets into the stream - more strict legislation about this now in NA, but still a problem in NA, and worse in many areas around the world.

Index surveys

Surveys that are conducted with standardized methods to compare relative abundance - between populations - over time - between survey methods In Ontario there are many different types of index surveys (e.g FWIN)

Solutions

These days, we are much more aware of many of these issues in NA (despite the fact that many continue to be major problems). We are also making some headway on solutions to some of these problems... Some examples of solutions: - Marine protected areas, sanctuaries, and conservation reserves - Dam removal - Stream restoration Where are we now? - Much of the damage is historical... Era of restoration and awareness • Role of science will be to evaluate the effectiveness of restoration projects, MPA's etc • Science and management associated with restoration needs to be "adaptive" with regard to what works & what doesn't. • Science needs to provide information about the "habitat requirements" for species at risk, endangered species (all life stages) etc • Science needs to provide information about the best way forward for new sustainable energy projects (hydro, wind etc) - Impacts on habitat and species - Improved fish passage, flows etc • Need to defend appropriate habitat legislation • Unfortunately, time is always an issue...

Summary re: hatcheries

These issues have been hotly debated in the world of fisheries for the past few decades. In some geographical areas (eg Pacific Northwest US), hatchery programs are now being heavily scrutinized and major changes have been made to hatchery programs. Some hatchery programs, such as those for Atlantic salmon in Canada, have also been eliminated from government budgets (based on some of this rationale, but also as budget cuts!). Much of the criticism contained within this lecture applies to historical hatchery practices, but in some areas many of these practices still persist. It is interesting to talk to the general public about this issue. Many recreational anglers and cottagers simply believe that more stocking equals more fish to catch in their lake. Much of the general public is also completely unaware of the issues discussed in this lecture. There is still not agreement on all of the issues in this area this area, but it is very important for the next generation of fisheries biologists, as well as students obtaining a biology degree and taking a course such as this (all of you!) to understand these issues and help inform society going forward, so that better decisions can be made on some of the important issues discussed in this lecture.

Assessing the fish

Total abundance is a complete inventory of the fish population and is rarely desirable or feasible. - Relative abundance is a sample of the population used to infer information about the population. - Two broad categories of assessment are used to assess the fish population: fisheries independent methods and fisheries dependent methods. - Both methods require catchability to remain constant between surveys in order to have comparable data. - Fishery-independent surveys: --> monitoring programs that are specifically used to assess the status of fish population --> they don't rely on information from fishers to determine the status of the populations --> usually conducted with specific objective by a government agency (e.g. DFO, OMNR) - Index netting programs provide standardized sampling methods in order to reduce the possibility that catchability differs between surveys. Due to the wide variation in catchability among species, managers often create index netting programs that specifically target and index one particular species. Fish shape is one factor that influences that catchability of fish particularly in gill nets. For these species, methods such as trap nets or electrofishing may be utilized as an alternative to gill nets. In addition to assessing relative abundance, index netting methods are also often used to collect data about the population such as collection of calcified structures for age interpretation, age of maturity, fecundity and fitness. - Hydroacoustic surveys are a method of indexing abundance in large waterbodies (such as marine environments) but are limited to indexing abundance (and to some degree size structure).

Fishery dependent surveys

Use the fishery as a monitoring index - CUE of the fishery can be used as an index of the abundance (for long term comparison --> q must remain constant) - Commercial and recreational fisheries behave differently

Why is history of inland fisheries science and management important?

We are now starting to look at the relationship between fisheries science and management and to learn the different roles that science plays in the management and conservation of fisheries resources. Some of the basic principles/concepts are introduced in this lecture. In order to understand how fisheries have changed and how they got to the state that they are now in, one needs to learn about the history of the fisheries. This lecture also discusses the history of inland fisheries and their science and management.

Why is habitat important?

We hear a lot about "overfishing" these days because many marine commercial fisheries are in serious decline. Overfishing is the primary reason for the collapse of many commercial ocean fisheries. In contrast, habitat issues are rarely in the news, but this issue has had (and continues to have) a huge impact on fish populations around the world, including those in North America. This lecture discusses some of the most important habitat issues affecting fish populations. In urban areas, the aquatic habitat that we see has often been altered in ways that we simply start to take for granted Habitat alteration is one of the most important factors affecting global fisheries. The root cause of this issue can ultimately be traced back to world population growth and the development and urbanization associated with it.

Why is evolution in fisheries important?

We know that there is potential for fisheries to create selection pressures that could result in evolutionary changes in fish populations because many harvest strategies select for certain sizes. In many commercial and recreational fisheries, we have historically targeted the largest fish for harvest. So, the main question addressed by this lecture is... "Have these selection pressures cause evolution to occur in commercial or recreational fisheries?"

Aquaculture: future

We need more inland recirculating systems and less open cage culture in natural waterbodies inland: - Lots of science & opportunities (growing industry) here - New technologies - renewable energy - Local food production (close to urban areas) - Many new species opportunities (native species) - Aquaponics systems should thrive...lots of challenges, but lots of potential - New feeds - science & opportunities - Should largely replace commercial harvest of wild species

Hatcheries and stocking: future

We need more new roles, re-introduction, and species at risk • Much better understanding of the impacts and limitations • Not appropriate as mitigation for habitat destruction • Much better science in this area regarding genetics & strategies • Roles changing from enhancement to re-introductions, re- habilitation of species at risk, preservation of stocks/strains etc Greatest threats: • Habitat loss & degradation • Invasive species • Loss of biodiversity • Climate change Greatest Assets • Better understanding than any other generation • Better technology to collect information & facilitate change • Resiliency of nature

Why is surplus production important?

We've heard a lot about "overharvest" of fisheries in this course. You've probably heard lots about it elsewhere as well. Interestingly, there is actually a lot of very good science that goes into the process of determining appropriate harvest levels. There are still some big unknowns that can influence how accurate these predictions are, but many of the real problems associated with the "overharvest" issue are social and political problems. This lecture describes the basic biology and surplus production models that are used to determine appropriate harvest levels in fisheries. Surplus production tells us how many fish we can harvest sustainably

History of fish stocking and hatcheries

When humans first recognized that we were having a negative impact on fish populations (1700-1800's), one of the first responses was to try and figure out how to produce more fish (technological fix), rather than reduce harvest. This was the initial reason to learn more about how to produce fish, rather than rely on nature to do it for us. When North America was being settled by Europeans, people also wanted to catch the fish they liked in places they were settling. This led to further efforts to produce fish in hatcheries. It also resulted in new species being introduced to North America (eg Brown trout). During the era of dam building in North America (1900's), hatcheries were also viewed as appropriate mitigation for loss of habitat. This led to a huge proliferation of hatcheries during this period. Still today, many hatcheries are located very close to sites where there are major dams (evidence of the thinking at the time). The rationale that we can just produce the fish we want in natural waterbodies continued for many years and led to the huge number of hatcheries that we have today. During the 1980's and 90's, people began to question whether all this hatchery production of fish was a good idea. Questions began to arise about the potential negative impacts of stocked hatchery fish on wild populations.

Assumptions and Unknowns of Surplus Production

• An important limitation of surplus production models is that recruitment is assumed to be solely dependent on population size (numbers of spawners). • We know that the fluctuations in environmental conditions can affect recruitment, but this is not taken into account • There are also differences in the way harvest can be implemented in different fisheries (causing further uncertainty & precautions) • In commercial fisheries, exact harvest quotas can be set • In recreational fisheries, managers typically set creel limits (quota/day fished) and include assumptions about angler behaviour • In some fisheries (eg migrating salmon), fish numbers can sometimes be counted (eg at a ladder) and population size is easy to determine. • In other fisheries (ocean, lakes), population size is estimated based on assessment data (uncertainty in these estimates) It is a challenging job to try and predict optimum harvest for a fishery, but it can be done using biological principles and information. We also need to recognize uncertainty and unknowns and be sufficiently precautionary in these predictions

Optimum Yield vs. MSY

• Because there are many assumptions in surplus production models and there are still some unknowns, it is a lot safer to aim for a harvest that is less than MSY... Optimum (safer) population size at S4 instead of S3

Difference between commercial and recreational fisheries

• In recreational fisheries, there is also a harvest target calculated by a surplus production model, but there is no exact way to determine when that target is reached in real time. • This is because of the nature of recreational fisheries compared to commercial fisheries. • In most recreational fisheries, anglers typically have limits per day and don't report catch. • So, comparing relative abundance data through time from assessments (or other monitoring) is the most common way to determine if regulations need to change in recreational fisheries • Good assessment information is very important Another important difference between commercial and recreational fisheries... "Licenses" --> In most cases, individuals must obtain a license to participate in the fishery --> Recreational fisheries - typically open to everyone who wants to buy a license --> Commercial fisheries - limited number of licenses Until now, qXN = F (total mortality from fishing) where: q = catchability X = effort N = Population size But in recreational fisheries, "catchability" or "q" can be further broken down... In recreational fisheries... q=cxh where: q = catchability c = catch rate of angling gear h = harvest So, in recreational fisheries, there are more options to adjust fishing mortality (F)... In rec fisheries, F can be adjusted by changing 1) effort (X) 2) catch rate of angling gear (c) 3) harvest (h) Regulations for recreational angling usually affect one of these 3 variables

Marine protected areas: future

• Need more - 10-30% of our oceans • Lots of science, assessment and enforcement needed for these to understand what is needed for different species & what works vs not

Recruitment assumptions

• One of the "wild cards" in this area is the fact that all of these regulations and models assume normal (average) levels of recruitment. • Bad recruitment years due to things such as acute environmental changes can play havoc with predictions. By now, you should be able to see why these things all work together in a best case scenario that involves regular assessment etc. One term used to describe all this working together in a best case scenario is... "adaptive management" Adaptive management • Something we hear a lot more about these days • Process that involves setting goals and objectives (eg target population size & structure), implementing strategies to achieve objectives, monitoring and assessment (have objectives been achieved?) and then making adjustments (if necessary) to achieve goals

Logistic type surplus production models

• Simplest surplus production models • Very similar to previous equation, but also include variables to quantify fishing losses • Growth, recruitment and natural mortality are combined into a single variable (r)....the rate of population increase • More sophisticated surplus production models take more biological information about the species into account... Equation for simple logistic-type surplus production model.... dN/dt = rN [(K-N)/K)] - qXN where: N = population size T = time r = rate of population growth K = carrying capacity (ie max density without fishing) q = catchability (a constant) X = fishing effort So...q X = mortality rate from fishing Predicted responses of a population to different types of fishing pressure using a logistic-type surplus production model (graph in lecture 14) Explanation of points in the previous Figure: A = fishing is intensive, but the time interval is long, so the fish population recovers B = fishing is much less intense and population recovers completely in shorter amount of time C = moderate fishing intensity, but time for recovery creates an equilibrium where population recovers to the same point after each fishing episode. D = more frequent fishing episodes cause stock to collapse E = excessive fishing drives stock to extinction.

Recreational fisheries: future

• Strive for sustainability through selective harvest & sound science, assessment and management. • Important to maintain interest in conserving aquatic environments • Potential for increase with habitat improvements (eg dam removal, restoration of inland habitat • Important role in educating youth & connecting them to aquatic conservation - many future fisheries biologists!

Basic principles of surplus production

• The 2 factors that will decrease the biomass of a fish stock in a given year are natural mortality (N) and fishing mortality (F) • Similarly, the 2 factors that will increase the stock's biomass are growth (G) and recruitment (R). S2 = S1 + R + G - M - F where: S2 = weight of the stock at the end of the year S1 = weight of the stock at the start of the year R = weight of new recruits G = growth of fish remaining alive M = weight of fish removed by natural deaths F = yield to the fishery When the population is at equilibrium (stable), S1 = S2 and so... R+ G = M + F ...growth and recruitment is balanced by natural mortality and fishing mortality When the population is being exploited (fished), but stable, recruitment + growth = natural losses + fishing yield. When exploitation is happening, the overall size of the population is usually reduced and there is compensation in the factors that tend to increase population size...We typically see.: Greater recruitment, Greater growth rates, Reduced natural mortality

Important points Re: Surplus production

• The highest production from populations that grow in a sigmoid fashion is not near the top of the curve (ie not at high density). • Rule of exploitation = max yield is obtained from populations well below the maximum density These principles and the associated equation(s) are the basis for the simplest surplus production models