Final

Invasiveness - Evolutionary Explanations

• New NIS experience relatively intense selection • obs. pops. start small and explode to invasiveness • hyp. rapid expansion results from local adaptation • (or conditions become more favorable) First establishment then population skyrocket and "overshoots"

Emergent Property of Alewife Invasion

Emergent Property of Alewife Invasion • a lot of alewife in piscivore diets • alewife have high levels of thiaminase • limits ability to store thiamine • = a diet of alewife is very low in thiamine • carbohydrate metabolism compromised "Cayuga Syndrome" • up to 100% mortality of larval Salmo salar • "swim-up" or "early mortality syndrome" in Salvelinus namaycush • up to 60% larval mortality

Increased P --> periphyton biomass increase

Eukiefferiella Generational Transfers: Indirect Decomp of dead fish, convert into molecules to ingested by diatoms and nutrients via autotrophis for the heterotrophs to eat. This is how energy goes back into the population of the young fish after spawning and this brings that major nutrient jump like N into the systems. If these carcasses are getting into the rivers are they getting into the watersheds like lake superior. Salmon Effects • Increased P periphyton biomass increase Lake Superior Salmon Runs • salmon-derived N in algae downstream from carcasses • in grazing mayflies and net-spinning caddisflies • no evidence for salmon-derived C incorporation

Know which experimental evidence applies that initially made zebra mussels more invisible

Experimental Evidence: Respiration Rate Assimilation Efficiency Adult Size Minimum Gametogenesis Temperature Time to maximum density Energy expended for egg production Byssal thread synthesis rate Byssal thread strength

The Eurasian round goby (Neogobius melanostomus)

Extensive negative impacts on native fish populations Another Ponto-Caspian invader with extremely broad environmental tolerances • DO down to 0.03 mg/L (hypoxic zones) • salinity from freshwater to 40.6 ppt (seawater ~ 30) • -1 - 30°C • tolerate chronic exposure to toxins • bioaccumulation and biomagnification (increases with trophic levels) The Eurasian round goby (Neogobius melanostomus) invaded the freshwater North American Great Lakes in ~ 1990 via accidental introduction from ballast water discharge. Its genotypes in the Great Lakes traced to estuaries in the northern Black Sea, where the round goby flourishes in a variety of salinities to 22 parts per thousand (ppt). To prevent further introductions, U.S. and Canadian Coast Guard regulations now require that vessels exchange ballast water at sea before entering the Great Lakes. Since salinity tolerance of the invasive round goby population is poorly understood, we tested 230 laboratory-acclimated fish in three experimental scenarios: (1) rapid salinity increases (0-40 ppt), simulating ballast water exchange, (2) step-wise salinity increases, as during estuarine tidal fluxes or migration from fresh to saltwater, and (3) long-term survivorship and growth (to 4 months) at acclimated salinities. Almost all gobies survived experiments at 0-20 ppt, whereas none survived ≥ 30 ppt, and at 25 ppt only 15% withstood rapid changes and 30% survived step-wise increases. Ventilation frequencies were lowest at 10-15 ppt in step-wise experiments, in conditions that were near isotonic with fish internal plasma concentrations, reflecting lower energy expenditure for osmoregulation. Growth rates appeared greatest at 5-10 ppt, congruent with the larger sizes reached by gobies in Eurasian brackish waters. Thus, we predict that the Great Lakes round goby would thrive in brackish water estuaries along North American coasts, if introduced. However, oceanic salinities appear fatal to the invasive round goby, which likely cannot withstand complete seawater ballast exchanges or oceanic habitats. Trophic transfer of polychlorinated biphenyl (PCB) congeners in zebra mussels (Dreissena polymorpha), round gobies (Neogobius melanstomus), and smallmouth bass (Micropterus dolomieu) were assessed in four sites along the south shore of the west and central basin of Lake Erie (all sites were in OH, USA). Total PCB levels in smallmouth bass (1,091-1,520 ng/g wet weight) and round gobies (118-256 ng/g wet weight) were similar among sites despite a west-to-east decrease in total PCB concentrations in zebra mussels (29-97 ng/g wet weight). At all sites, PCB body burden increased three- to fivefold at each successive trophic level, suggesting biomagnification in this nonnative food chain. Whereas fish species were dominated by thehexachlorine homologue, zebra mussels were dominated by penta- and hexachlorine homologues; the average degree of chlorinationof PCBs was 56.1% for zebra mussels, 60.4% for round goby, and 59.9% for smallmouth bass bodies. Predictive structure-activityrelationships based on chemical characteristics, such as the octanol-water partition coefficient (log Kow), had little predictive poweron bioaccumulation and biotransformation of PCB congeners because of nonlinearity, threshold relationships, and species-specificdifferences. Calculated trophic transfer for the smallmouth bass-round goby linkage was higher than for the round goby-zebramussel linkage. Only when PCB congeners were grouped by chemical structure first (vicinal [adjacent] H-atom position in thephenyl ring) were linear relationships achieved. It appeared that the chemical group to which each congener belonged influencedbiotransformation more than species-specific (round gobies vs smallmouth bass) differences. Biotic changes at midtrophic levels,such as exotic species invasions, may have an increasingly important role in determining pollutant cycling and hence pollutantresidues in top predators.

Are the Great Lakes particularly vulnerable to invasion?

(high Invasibility) • Colonization Time Hypothesis • hyp. (still) open niches (Elton) • Exploiting Open Niches • microhabitat invasion (Hot microhabitats (27-30°C)) • open temporal niches

alewife have high levels of thiaminase Thiaminase: an "anti-nutrient"

A lack of thiamine (vitamin B1) is linked to the condition known as 'M74' in eyed eggs of wild Atlantic salmon and sea-trout in the Baltic area. The deficiency continues through the fry stages. Early mortality syndrome (EMS) and Cayuga syndrome are recognised as more or less identical conditions in several wild salmonids in the Great lakes area in North America. These conditions are characterized by up to 100 % mortality in progeny from certain female fish. Clinical signs include spiral swimming, loss of equilibrium and hyperexcitability, lethargy, dark body and subcutaneous oedema. Affected fry go off the feed and develop hydrocephalus, yolk-sac precipitate and haemorrhage (Fig. 10.24). Histologically, characteristic lesions are found in the molecular layer of the cerebellum developing cellular degeneration and necrosis, nuclear pyknosis and karyorrhexis, and sometimes haemorrhage. It is generally accepted that these lesions are the consequence of thiamine deficiency in the female. Salmonids are top predators and some of their prey may include forage fish with high levels of thiaminase, e.g. alewife in the Great Lakes region and sprat and herring in the Baltic Sea. The composition of the forage fish diet may be variable from 1 year to the other and individual fish may have different feeding strategies explaining the female dependant factor. High thiaminase levels results in low levels of thiamine in eggs and progeny with resultant characteristic signs of thiamine deficiency. These conditions can be prevented or reversed by exposing eggs or fry to thiamine. Females can also be injected with thiamine prior to stripping in order to avoid the condition. White spot disease and blue-sac disease are both differential diagnosis

Invasion via live game fish transport?

Able to survive fish guts, Can live for up to 50 days on damp surfaces Like boots, water boots hyp. Great Lakes populations arrived via ballast water from Europe Potamopyrgus antipodarum can survive passage through the guts of fish and may be transported by these animals (Bruce 2006). It can also float by itself or on mats of Cladophora spp., and move 60 m upstream in 3 months through positive rheotactic behavior (Zaranko et al. 1997). • parthenogenic live bearers (rare males) • ~230 young per female • eurythermic (0-34°C) • euryhaline (0-5 ppt optimal, growth up to 15) • can tolerate up to 35 for short periods • up to 5600 m2 in Lake Ontario • 4-45 m sand and silt • Foot anatomy, perculum

Abyssal Benthos is

Abyssal Benthos, we are looking at vermiform organism that wormy and burrow, ex: midges. Both of them have hemoglobin and leving in/on the lake bed. You reach the bethnic nipholoid layer just above the bottom that is very thin so it is hard to get [DO] from what is right above them. The lil wormies get this by ungulation. Moving aka ungulating in order to take break down the surface tension of surrounding h2o and using the hemoglobin to get that oxygen

How organisms in the abyssal benthos get O2

Boundary layer DO is high but Gill [DO} is low leads to DO being diffused into gill. Wen boundary layer DO is low gill [DO] is high leads to slower diffusion. Gill movement breaks up the boundary layer and replenishes the DO supply near the gills.

Kiyi (Coregonus kiyi kiyi)

Description • The Kiyi (Coregonus kiyi kiyi) is among the deepest water forms of cisco species found in Canada. It is a member of the Salmonidae family and has the following characteristics: • laterally compressed body with large eyes that comprise 22 to 26 per cent of the head length; • terminal mouth with lower jaw usually extending beyond the upper jaw; • mainly silver in colour with some pink and purple iridescences; • long paired fins; • sexually mature between ages two and five years; and • typical measurements range between 100 and 200 mm, and weights of 10 to 60 g, but have been recorded in excess of 300 mm and 125 g. Habitat • The Kiyi is endemic to all of the Laurentian Great Lakes except Lake Erie. The Upper Great Lakes population (Coregonus kiyi kiyi) is believed to currently exist only in Lake Superior. Believed extirpated, it was last recorded in Lake Huron in 1973 and in Lake Michigan in 1974. The Lake Ontario population (Coregonus kiyi orientalis) is considered extinct, last recorded in 1964. • Kiyi appears to be widely distributed in the deep waters of the offshore (generally most abundant at depths of 150 m) making up a significant proportion of the fish community in Lake Superior. They are also found in reduced numbers in the shallow waters of the nearshore. Kiyi move to shallower water depths at night, typically less than 50 m, in search of their prey. • Little is known about the habitat preferences and life history of the Kiyi. It lives in a clear, cold-water environment at depths ranging from 10 m to 305 m, with peak abundances found at depths between 130 to 150 m. Kiyi have been collected over lake bottoms of clay and mud substrates. Spawning generally occurs in the late fall at depths between 91 and 168 m. The age of maturity is between two and five years. The maximum known age for females is 22 years, and 16 for males. The Kiyi is prey for Burbot (Lota lota) and deepwater forms of Lake Trout (Salvelinus namaycush). Kiyi eggs may also provide a prey source for other fish, including Lake Whitefish (Coregonus clupeaformis). The Kiyi feeds on deepwater crustaceans such as Mysis relicta and Diporeia hoyi. Secondary prey items chironomids, calanoid copepods, clams and Daphnia species. • Threats • Commercial overfishing of Kiyi was likely the cause of its decline in lakes Huron, Michigan and Ontario. Remaining Kiyi populations in lakes Huron and Ontario likely have competed with, or have been preyed upon by, introduced fish species such as the Sea Lamprey (Petromyzon marinus), Alewife (Alosa pseudoharengus) and Rainbow Smelt (Osmerus mordax). Other issues, including degraded water quality (from the continuing pressures of contaminant and nutrient inputs in the Great Lakes) are also ongoing, with likely impacts on Kiyi survival and habitat. Climate change has been identified as a possible factor that could worsen the situation in the future. Lastly, certain pathogens, particularly viral hemorrhagic septicaemia (VHS), have the potential to generate mass mortality in a variety of fish species. Detected in Lake Superior watershed in 2010, future outbreaks of VHS could decimate the remaining Kiyi population.

What are causes of hypoxic zones in Lake Erie?

Lake circulation patterns control transport of nutrients in Lake Erie and this increased transport from the western to the central basin, in June it coincides with the period identified as critical for SRP loading (May to July), and is well aligned to deliver nutrient-rich water from the Maumee and Sandusky rivers into the main portion of the central basin.

Eurytemora affinis

Ecology: Eurytemora affinis can live for up to 73 days and the juvenile stage lasts around 11-37 days. Females can lay around 2-34 sexual eggs per day, which develop in 1-14 days (taking the longest at temperatures of 5ºC and developing most quickly at temperatures around 22ºC). This species carries sexual eggs until they hatch. Diapausing eggs are usually produced in the fall and then stay in the sediments, remaining viable up to 10-18 years, even in anoxic conditions. Eggs have the ability to survive passage through the digestive tracts of various fish species. Diapausing egg production is related to short day length, low temperature, and high copepod population density (Ban 1992; Flinkman et al. 1994; Katajisto 1996; Andersen and Nielsen 1997; Katajisto et al. 1998; Roman et al. 2001; Wonham et al. 2005). Population peaks are present at different times of year in different regions of the world. In the Milwaukee Harbor, it is present from July to November but absent in winter and spring, while in the northern Baltic Sea it is known to overwinter at low population density. In the Atchafalaya River system in Louisiana it occurs at its highest abundance in early summer, while in two European estuaries, the Gironde and the Westerschelde, it is dominant in winter and spring. In a Scottish estuary, the Forth, it is dominant in winter and summer (Roddie et al. 1984; Tackx et al. 1995; Davidson et al. 1998; Katajisto et al. 1998; Torke 2001). Eurytemora affinis is epibenthic, inhabiting both the sediments and the water column in Lake Michigan, where it is often particularly abundant in the first 10 m of water. In this lake, abundance in the water column is significantly higher in the day than at night in June, and then evens out later in the summer. In Lake Michigan, the presence of E. affinis in sediments increases in late summer. It spends winter and spring as eggs (Wells 1970; Nalepa and Quigley 1985). Eurytemora affinis can tolerate salinities of 0-40‰. In Chesapeake Bay, it is most abundant in waters of 5-10ºC and salinities of 3-8‰ but can tolerate higher salinities at lower temperatures. High salinities at high temperatures are stressful. Experiments indicate that optimum temperature and salinity ranges for this species are 10-15ºC and 5-15‰ respectively. Interestingly, one Japanese experiment showed that individuals introduced to freshwater from a brackish water source are still best adapted to salinities of 5-15‰, and that eggs from this population hatch well at salinities of 0-20‰. Eurytemora affinis can tolerate high turbidity, although production may decrease due to low food availability from lack of light and difficulty in selecting edible particles. In some European estuaries, this species is considered limited by high turbidity and anoxia (Sautour and Castel 1995; Burdloff et al. 2000; Kimmel and Bradley 2001; Roman et al. 2001; Seuront 2006). Eurytemora affinis grazes on algae, bacteria, organic detritus and protozoans, including ciliates and dinoflagellates. It can increase feeding on heterotrophic plankton rather than autotrophic plankton when suspended particulate matter increases in concentration. Feeding on microplankton ciliates is most efficient due to better perception, handling, and relative nutritional quality of these larger food particles in comparison to phytoplankton (Gasparini and Castel 1997; Merrell and Stoecker 1998; Torke 2001; David et al. 2006). Means of Introduction: Llikely introduced in ballast water from the Atlantic Coast or from western European ports in ships arriving in the Great Lakes basin. It does have a diapause stage that can be found in aquatic sediments, but it is most ubiquitous in ballast water samples (Mills et al. 1993; Wonham et al. 2005). Possibly introduced with fish stocking. Status: Considered established in all the Great Lakes with high populations. Established inland. Impact of Introduction: the coastal copepod Eurytemora affinis has made remarkably rapid and frequent saline to freshwater transitions within the past century. This copepod has invaded freshwater habitats multiple times independently with the advent of ballast water shipping and discharge into freshwater lakes. Eurytemora affinis • hypersaline to oligotrophic • range not attributable to plasticity • strong selection heritable shifts in tolerance • e.g., heritable shift in tolerance of low salinity

Cladophora

For the past five years, large quantities of decaying algae, called Cladophora, have been fouling Wisconsin´s Lake Michigan shoreline. As the algae and organisms trapped in the algae rot, they generate a pungent septic odor that many people confuse with sewage. Nutrient sources like phosphorus and nitrogen, zebra mussels and declining lake levels have been implicated in the recent increase in nuisance algae. The presence of rotting Cladophora on Lake Michigan beaches presents aesthetic and odor problems that impair recreational use of Lake Michigan. Cladophora is a green algae, and does not produce toxins the way blue-green algae can. Cladophora itself does not present a risk to human health. However, Cladophora rotting on a beach promotes bacterial growth that can pose a risk to human health. In addition, crustaceans that wash up with the algae can attract large flocks of gulls, resulting in high concentrations of fecal material and bacteria.

Impacts of mud snails: Echinogammarus ischnus

Human-disturbed ecosystems are more susceptible to mud snail invasion Remember the filters it takes for an organism to become a pest, invisibility or invasioness https://link.springer.com/content/pdf/10.1007%2Fs10750-008-9529-3.pdf Ovoviviparous, females brood their offspring to the ''crawl-away'' developmental stage in a brood pouch Before a species becomes a pest in an ecosystem, it must successfully overcome several filters. First, the species must travel from its native range to a new ecosystem (transport). Second, it must survive, grow and reproduce under the new environmental conditions (establishment). Third, it must acquire a high rate of population growth, invading new regions (spread). Finally, the alien species must alter the structure and functioning of the invaded ecosystem (impact). Wide tolerance to physico-chemical conditions contributes to explain the success of mud snail in the two former steps to become an invasive species (transport and establishment). However, a successful establishment also relies on a high capacity to overcome biotic resistance, either by successfully colonizing early stages of succession in human-altered habitats, or by leaving behind parasite and predator control. Its high reproductive rate, together with its ability to disperse by active and passive mechanisms, explains mud snail potential for an efficient spread. Finally, mud snail ability to alter the structure and function of invaded ecosystems (impact) is again due to the high reproductive rate, which leads to extremely high population density and to the consumption of most of the primary productivity of the ecosystem. Therefore, the coincidence of wide tolerance to abiotic factors and high reproductive capacity on the same species may have allowed it overcome most of the filters to become a pest. Human-disturbed ecosystems are more susceptible to mud snail invasion than intact ones, although the latter may be also affected by mud snail. In non-native regions, mud snail has been mainly found in human-disturbed environments, as occurs with other exotic species. Human induced disturbances increases the chance of success for recently arrived species, either by increasing resource availability (i.e. eutrophication), or by releasing resources capitalized by local populations. In habitats altered by human activities, P. antipodarum performs as a successful early colonizer dominating the incipient community, probably due to the low biotic resistance exerted by the remaining simplified native communities. The escape from parasites can additionally contribute to explain mud snail successful establishment, as it seems to leave their trematode parasites behind when invading new regions. Experimental studies have shown that P. antipodarum growth was reduced by the presence of trematodes. Finally, mud snails are also resistant to many native predators, because of its hard shell and solid operculum. All these traits can help mud snail for a successful establishment in a new area. https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=23 Ecology: Echinogammarus ischnus only reproduces sexually and has no resting stages. Brood size varies from 2-51 eggs. Breeding often occurs in spring and summer and ends in the fall, but may occur twice throughout the year in warm, thermally stable waters (Witt et al. 1997; Kley and Maier 2003; Kley and Maier 2006). Echinogammarus ischnus is a euryhaline species that is most common in large northern rivers of the Black and Caspian Sea drainages (Kohn and Waterstraat 1990; Cristescu et al. 2004). It has been recorded at depths ranging surficial to 300 m on mud, silt, sand, rock, Dreissena mussels and under wrack (Kohn and Waterstraat 1990; Witt et al. 1997; Nalepa et al. 2001; Grigorovich et al. 2003; Kley and Maier 2005). Its occurrence and density in the upper St. Lawrence River is positively correlated with current velocity and the availability of gravel-sized sediment (Palmer & Ricciardi 2004). It can tolerate highly eutrophic conditions and temperatures up to an absolute maximum of 33-35°C (Kohn and Waterstraat 1990; Wijnhoven et al. 2003). Echinogammarus ischnus feeds on deposits - including those associated with zebra mussels, and preys on other macroinvertebrates such as chironomids, other amphipods, or its own species (Krisp and Maier 2005; Limen et al. 2005). In general, E. ischnus is more carnivorous than amphipods such as Gammarus fasciatus and Hyalella azteca (Limen et al. 2005). Means of Introduction: Echinogammarus ischnus was almost certainly introduced in ballast water (Witt et al. 1997). Its subsequent introduction to a port in Lake Superior (Grigorovich et al. 2003) was likely caused by a separate introduction in ballast water, either from a saltwater vessel or a domestic freighter from another port. Status: Established where recorded except possibly Lake Superior, where only two individuals have been found to date (Grigorovich et al. 2003). Impact of Introduction: A) Realised: E. ischnus is now among the most abundant non-Dreissena invertebrates in benthic communities in the Lake Ontario, L. Michigan, and L. Erie watersheds, where it has displaced native Gmelinoides fasciatus from many areas (Dermott et al. 1998; Stewart et al. 1998a, 1998b; Nalepa et al. 2001; Ratti and Barton 2003; van Overdijk et al. 2003; Haynes et al. 2005). Habitat heterogeneity in the St. Lawrence River may be promoting the co-existence of both species by allowing them to segregate along physicochemical gradients (Palmer & Ricciardi 2004). It is possible that E. ischnus has benefited from a co-evolved relationship with dreissenid mussels (Ricciardi & MacIsaac 2000). Structural complexity of Dreissena mussel substrate in combination with available nutrition from mussel biodeposits may have given E. ischnus a competitive advantage, stimulating its population expansion in the lower Great Lakes (van Overdijk et al. 2003). However, native amphipods consume dreissenid mussel pseudofeces more than the invader does at some sites, thus mussel habitat structure alone could enhance E. ischnus dominance over native species in the Great Lakes (Limen et al. 2005). E. ischnus in the St. Lawrence may be more susceptible to predation amongst dreissenid mussels than G. fasciatus, and predation may allow for coexistence of introduced and native species (Palmer and Ricciardi 2005). In the Great Lakes, however, E. ischnus is found more frequently amongst introduced mussels where native amphipods obtain refuge from predators amongst macrophytes and Cladophora-encrusted habitats (van Overdijk et al. 2003; Gonzalez and Burkart 2004). B) Potential: This species has also been introduced to Western Europe and the Baltic Sea (Cristescu et al. 2004). In parts of Germany and Poland, it has reduced or replaced native gammarids (such as G. fossarum, G. roeseli and G. pulex) (Jazdzewski et al. 2004; Kinzler and Maier 2006). In streams in Central Europe, introduced E. ischnus and Dikerogammarus villosus appear to have contributed to declines in some native macroinvertebrates through predation (Krisp and Maier 2005). It is possible that with increasing colonization of D. bugensis in deeper waters of the Great Lakes, E. ischnus may follow (Nalepa et al. 2001). Canal systems promote the dispersal of this species throughout Europe and may aid its further dispersal in North America (Witt et al. 1997). Remarks: Found in shallow margins of lakes and large rivers with gravel or rocky bottom; can tolerate lakes with mud bottoms. Females brood sizes can have as many as 48 individuals in their native range and can reproduce all year in favorable conditions.Although there is great genetic variation amongst native populations in the native Ponto-Caspian region, one mitochondrial genotype of this species from the Black Sea has been responsible for invasions from the Rhine River to North America. (Cristescu et al. 2004).

How do benthic species end up in ballast holds?

Mollusks specifically bivalves have first larval stage they are plantonic and small, then a second larval stage where they have velum aka fallengies that help swim.

Fast facts about hypoxic zones

Not dead zones, high cyanobacteria abundance 1.5 m below thermocline during hypoxia events • diverse heterotroph community in "dead" hypoxic zones • During these periods whether persistent or seasonal, energy moves away from mobile predators to the microbes.

Coregonus artedi, cisco

Narrowly defined, Coregonus artedi is known variously with the common names cisco, northern cisco, lake herring, chub or tullibee and its Anishinaabe name Otoonapii. It is a pelagic fish occurring in the midwater zone of cold water lakes in North America. In the northern and western parts of its range it is also found in large rivers. This species occasionally grows as large as 40 cm and 2.3 kg (five pounds) but is more commonly 28 to 38 cm long and 170 to 907 grams (six ounces to two pounds) in weight. It is slender-bodied and silvery with pinkish iridescence on its sides. Diet is predominantly zooplankton and insect larvae, although fish eggs and larvae, including those of their own species are also documented. Small fish, including some minnow species, are also known to be consumed at times. Northern cisco are preyed upon by a wide variety of predatory species, and have a particularly important place in the diet of lake trout (Salvelinus namaycush). It is also a common food of rainbow trout (Oncorhynchus mykiss), northern pike (Esox lucius), burbot (Lota lota), yellow perch, (Perca flavescens) and walleye (Sander vitreum) where the species overlap ranges. The abundance of northern cisco in the North American Great Lakes is much reduced from the levels of the 19th Century. Once abundant in all five lakes, it is now common only in Lake Superior. The Lake Huron population has been increasing recently, perhaps as a consequence of low alewife (Alosa pseudoharengus) abundance. Limited numbers have also reappeared in Lake Michigan's lower Green Bay. Numbers in Lakes Erie and Ontario remain far below historical levels. The reduced abundance is believed to result from the cumulative effects of several factors, including the expansion of non-native species such as alewife, rainbow smelt (Osmerus mordax) and sea lamprey (Petromyzon marinus). These species prey on and compete with various life stages of northern cisco. It is unclear what effect the annual stocking of several million non-native Pacific salmon in the Great Lakes has had on northern cisco. Additionally, substantial environmental degradation in some parts of the range has undoubtedly contributed to the stresses on northern cisco populations. The populations are therefore believed to be more vulnerable to the effects of exploitation than previously, even at levels of harvest lower than what was once sustainable. The cisco is also very sensitive to changes in temperature and levels of dissolved oxygen. Northern cisco are fished commercially and for sport. In the early years of the fishery, herring provided some of the largest catches from the Great Lakes and, when salted down or smoked for preservation, provisioned much of the surrounding territory. Northern cisco roe is also valued on the international market. Adaptive radiation review: "... species arriving after long intervals in a new and isolated district, and having to compete with new associates, will be eminently liable to modification, and will often produce groups of modified descendants." (Darwin 1853: 390) Available resources subject consumers to distinct selection pressures on traits relating to resource exploitation.

SRP

Soluble reactive phosphorus loading

Why so few NIS?

Survey Results - 5-10% NIS • only 2 pelagic spp. (Eubosmina coregoni Duluth-Superior, Bythotrephes longimanus widespread) • Zooplankter • Bosmina coregoni 3 Eurasian pea clam spp. "new" to lake • Sphaerium corneum, Pisidium amnicum Thunder Bay • Pisidium moitessierianum 145 m2 Superior Harbor • brood eggs between gill lamellae • released at up to 1/3 adult size! • How did they get there? Always have been there as a cryptic invader Cryptic invasions from the early 19th Century? New Holarctic Annelida Records Vejdovskyella - 2 species + Ripistes parasita range expansion Fact - tiny annelids are very difficult to sample Potamopyrgus antipodarum

Invasibility

characteristics of ecosystems and/or communities that affect the probability of a species becoming invasive (The rise of the profuna morph and what happens to shell and sifen shape that allows them to occupy deeper habitat. )

Dreissena anatomy and filter feeding

https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=95 https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=5

Hypoxic

pertaining to a low level of oxygen

How do silent genes get turned back on?

signals from the environment or cells activate transcription factors (proteins) • these bind to regulatory regions and determine transcription level These changes in the environment has that influence on the on or off switch

Fast facts about hemoglobin

structure allows for reversible binding of O2 • high affinity hemoglobin (bloodworms) • release at low external O2 pressures • ≈ 9 minute supply • + anaerobic capacity (19 x less efficient) Hemoglobin is a molecular entity that is capable of reversibly binding and releasing oxygen in either extra- or intracellular milieus. It is present in scattered invertebrates in physical solution or in cellular sites while in vertebrates it is universally located in circulating erythrocytes. These cells serve as the vehicle for and otherwise foster the optimum utilization hemoglobin. Hemoglobin's variable sphere of respiratory activities can be viewed as reflecting the specific requirements for each organism in which it is observed.

Three nonmutually exclusive ways (A, B, and C) that plasticity can influence adaptive divergence.

three nonmutually exclusive ways (A, B, and C) that plasticity can influence adaptive divergence: A p weakened disruptive selection, B p increased gene flow, C p enhanced adaptive habitat choice and assortative mating. From left, a population invades a new environment with ample resources and evolves plasticity to utilize various resources. Divergent selection ensues due to increased resource competition and induces plastic responses or genetic diversification. If plastic responses weaken disruptive selection (A) or increase gene flow between diverging phenotypes (B), plastic generalists likely result. If adaptive habitat choice and assortative mating are sufficiently strong, plasticity promotes the formation of a reproductive barrier, and adaptive divergence may carry on. Adaptive habitat choice enhances the contribution of assortative mating to the evolution of reproductive isolation when plasticity is expressed in the same direction as genetic predisposition. When reproductive isolation evolves, ecological speciation can be reached. If plasticity is costly, further adaptation may cause reduced plasticity via genetic assimilation

Dreisesena and hypoxic zone

Eastern basin of lake Erie has big mussels and kind of western and hardly in central but in central they are tiny. There is no reproductive capacity with in the central area of the lake because if the hypoxic areas were fixed we might see their population's boom.

"The ruff"

"The ruff" shares the habitat with the perch it's cousin. Look live and act the same but are very different. Omnivorous, overlap: a fish called a ruff. A ruffes ability to detect a prey item while their swimming, the ruffe can detect it at great distance and greater swimming speed. They don't have the same tool kit and are successful and occur in the same habitats but in prey acquisition the ruffe has an advantage. + ruffe glide to prey after building up speed which minimizes interference. Foraging Abilities and Niche Breadths of Two Percids, Perca fluviatilis and Gymnocephalus cernua, Under Different Environmental Conditions Adaption is due to low light environment, the light reflectsoff the tapetum and are there to reflect light Has a sensitivity of the lateral line aka a chanel on the head and along the body like a cannal and that movement turns on these sensory structures that feel the movement of other organisms in the water based on the water coming at them. Seem like the ruffes lateral line has a degree of tuning to it and become more efficient in picking up signals from their more common prey like midges. And after that it goes down.

What and when is speciation? Uncle Ernie Mayr (book about biology)

Analysis of AFLP data revealed two genetic clusters that conformed to differences in geography (eastern and western groups), rather than hypothesized taxonomic boundaries. Not two different species but two different clusters of the same species. Using the entire dataset, STRUCTURE and FLOCK results provided clear evidence that samples were primarily divided in two clusters (Table 2; Fig. 3a). Clusters did not correspond to MT (as predicted by H2). Instead, clusters reflected the geographic location of lakes. An eastern cluster includes Lake Superior and lakes south and east of Lake Nipigon (except Scorch Lake). A western cluster includes Lake Nipigon, all lakes further west, and Scorch Lake (located where). obs. 2 Distinct Refugial Lineages: Polymorphisms have evolved independently in both (this has happened more than once, aka parallel evolution of the same flock at the same geological time frame.) • range expansion during high water episodes • anadromy "landlocking"

Bioturbation connection to aerobic respiration of lake sediments?

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes. While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming.

32Blue sac disease in Atlantic salmon yolk-sac fry

Blue sac disease in Atlantic salmon yolk-sac fry. Note periocular and gill haemorrhage The predicted lake trout TECeggs shown in Figures 6 and 7 indicate a 40-yr period during which TCDD toxicity-associated mortality of sac fry would adversely impact the population, regardless of effects caused by other stressors, either chemical or nonchemical. The plausibility of these risk predictions rests with the degree to which they are supported by independent exposure and effects information as well as epidemiological data. Limited data exist for the incidence of mortality of sac fry hatched from eggs of feral lake trout from Lake Ontario. Eggs collected in 1991 did not produce sac fry with observable blue sac syndrome or increased mortality as compared to controls (31). However, when the 1991 eggs were exposed to TCDD through injection, the LCegg50 was 47 pg TCDD/g egg (31). The apparent reduction of theLCegg50 from the expected average of 60-65 pg TCDD/g egg is consistent with the incremental contribution of 11 pg TCDD equivalence/g egg, which was measured in the feral eggs. Mortality associated with signs of toxicity that resembled blue sac disease was observed for sac fry hatched from eggs collected from Lake Ontario lake trout during the period of 1977-1984 (27, 87). Mean percent mortality, above control, of sac fry with blue sac disease in 1977, 1978, 1979, 1981, 1983, and 1984 (data kindly provided by H. Simonin, New York Department of Environmental Conservation) tended to slightly exceed the minimum TCDD toxicity equivalence model predictions (Figure 8). The observations The Most Sensitive Salmonids LC50 lake trout fry 60 ppt Rainbow trout fry 400 ppt A final observation, very relevant to this assessment, is the appearance of natural reproduction from the adult lake trout that originated as stocked fry. Although numbers of adult lake trout caught eventually declined in response to abrupt decreases in fry stocking around 1918 and 1930, the declines appear to have been delayed or reduced due to availability of lake trout both from the earlier fry stocking and subsequently from their progeny. The approximate periods of 1925-1932 and 1936-1940 are most suggestive of this effect. The presence during these periods of second generation adult trout, from fry which were stocked approximately 14 yr earlier, indicates that natural reproduction and fry survival was good at least until the mid-1930s. This would be consistent with the toxicity risk predictions made in this paper.

Chapter 4: the channel in the Lake Claire River

Chapter 4: the channel in the Lake Claire River is uber fast currents and was cut out in the 1800s. the seaway opened in 1959 and started bring in invasive species rapidly. 1988, Driessenia muscles were found; Vilaggers helps with food accumulating or gripping a surfaces. Zebra muscles invasion was directly caused by careless dumping of ballast water. Eventually became established, via the floating ecosystems which is basically what ballast water is found in cargo ships. As well as the spiny water flea. The "small fire" of the Cuyahoga River, the river was so bad that small sparks caused multiple fires through out the early 1900s. This was associated with chemical dumping and the absence of regulation of the filtering or cleaning of dumped waste. Eventually the 1969 fire is what sparked interest. The regulation of water vessel wastes did not include freighters. The biological contaiminated ballast water is the worst kind of pollution because it cannot be fixed by pluging a pipe of capping a smoke stack and it cannot decay or dispurse; it breeds. Before this recognition of the invasion there was NO American literature on the zebra muscles. Fr zebra muscle can latch on to a surface by excreting plack from it's foot that it uses to drag itself along a lake bottom. The gland then adds proteins to the glue which fuses and becomes tough leathery threads. One adult muscle can spin more than 500 of these tethers. The zebra muscle isn't usually found past 60 feet. Zebra muscles only feed during the warmer months. The quagga muscles later followed, and can go down to 540feet in water and doesn't require a hard surfaces to adhere to and feed year rounds. The quagga muscle problem is hard to grasp or see an end. They now stretch from shore to shore is now more of a muscle bed than an inland sea. Lake Michigans quagga mass in the past recent years has been calculated to be able to now filter the whole lake in less than two weeks.

How would Dreissena facilitate Cladophora blooms?

Clearer water for sunlight to filter down farther. Nutrient build up via psudeofecies, the dreissena can serve as a substrate for the cladophora to attach to, reduced competition for nutrients from the dreissena filtering. Eutrophications can be defined by lights, nutrients, etc. But also associated with green and slimy, but in this case the eutrophication is kept nearshore and the oligotrophication is offshore. Based on the [silica] because that inidates how much primary production is occuring. After the dreissena the amount ogf sillica increased because of availability. Versus diatom.... These graphs show oligrotrophication and the association of diatoms, silica, and

Dioxin-like Activity Chlorine atoms in 2,3,7,and 8 positions e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Dioxin-like Activity Chlorine atoms in 2,3,7,and 8 positions e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) Importance of Cl content • increases solubility in organic solvents and fats • decreases water solubility, resists oxidative metabolism Dioxin Characteristics • lipophilic • readily bioaccumulate • acute, subchronic, and chronic toxicities • US incinerators up to 16 nanograms/m3 • Swedish standard = 0.1 ng/m3 Toxicity Equivalency Factors • TEF of TCDD = 1.0 • most furans and dioxins 0.1-0.5 • most PCBs < 0.1 (0.00001-0.1) Highly carcinogenic, mutagenic, teratogenic • + suppression of immune system • e.g., thymus gland development Sources of Dioxin • contaminants and byproducts • most from incineration 1) thermal breakdown of chlorinated, organic, and trace-metal compounds at 1000ºC 2) molecular rearrangement during cooling max formation at 300ºC 3) Cu, Zn, and Cd catalyze reaction 1000-300ºC Natural Dioxins • OM + NaCl + combustion • dioxin • < 4% total US production • adverse health effects? Delignification

HANNAEA SUPERIORENSIS SP

Divergence to fill open niches • hyp. H. superiorensis was preadapted to a new ecological opportunity surf zone divergence Hannaea superiorensis does not appear to be sympatric with H. arcus in the modern Great Lakes, but it may have speciated from local river populations of H. arcus during the Late Pleistocene-Early Holocene to become adapted to the cold, high-energy wave zone of Lake Superior. HANNAEA SUPERIORENSIS SP. NOV., AN ENDEMIC DIATOM FROM THE LAURENTIAN GREAT LAKES Rebecca J. Bixby, Mark B. Edlund, and Eugene F. Stoermer Diatom Research 20, Issue 2, 2005 George Gaylord Simpson argued that shifts between 'adaptive zones' should cause rapid evolutionary radiations. Deep water divergence: Conditions in young, deep, isolated lakes favor depth related adaptive radiations. hyp. Adaptive radiation following C. artedi colonization

Round Goby and ballast water

Dumping ballast water means dumping other species so ignoculating the new habitat, such as dreissienna and the Round Goby. RG came from the black and Caspian sea and western Europe, eventually spreading to the great lakes. Obs: There is a small amount of taxa that are able to transition from saline to fresh water environments tend to comprise a relatively large portion of the freshwater invaders. They tend to have more control on osmoregulation (or the other kind??). The ballast hole are near the bottom so sludge build up is common.

Feeding behaviour of the zebra mussel Dreissena polymorpha

Feeding behaviour of the zebra mussel Dreissena polymorpha. (A-F) Frames from videos; (A-D) side views, (E,F) underside views. (A) Pseudofaecal material expelled by the inhalant siphon of the mussels when fed the non-toxic diatom Asterionella Formosa (Most common in Lake superior andmaybe all the great lakes). (B) Faecal material expelled by the exhalant siphon of the zebra mussel when fed the diatom Asterionella formosa. (C) Copious pseudofaecal material expelled by the inhalant siphon and copious pseudodiarrhoea expelled through the pedal gape of the zebra mussel when fed the toxic cyanobacteria Microcystis aeruginosa (strain CCAP 1450/10). (D) Copious faecal material expelled by the exhalant siphon and copious pseudodiarrhoeal material expelled through the pedal gape of the zebra mussel when fed the toxic cyanobacteria Microcystis aeruginosa (strain CCAP 1450/10). (E,F) Pseudofaecal material expelled by the inhalant siphon and pseudodiarrhoeal material expelled through the pedal gape of the zebra mussel when fed the toxic cyanobacteria Microcystis aeruginosa (strain CCAP 1450/10). InS, Inhalant siphon; ExS, exhalant siphon; Pg, pedal gape; PIn, pseudofaeces expelled through the inhalant siphon; FEx, faeces expelled through the exhalant siphon; PPg, pseudodiarrhoea expelled at the pedal gape. The Dreissena filter everything so they take in all the diatoms and what knot aka their preferred foods. Then the amount of microcystis is about the same still and still viable after the filteration. There for the microcystis now has much less competetition connecting the influx of of microcuystus to the influx of driesennia.

What happened?

LS Commercial fishing Lake trout populations in Lake Superior, already in decline from overfishing and environmental problems, were decimated by the sea lamprey invasion. Initiation of the sea lamprey control program resulted in a quick decline in the numbers of sea lamprey and allowed some recovery in the numbers of lake trout in Lake Superior. Alewife Invasion • range expansion during high water episodes • anadromy "landlocking" Lake Ontario 1860s • dominant fish since 1870s Erie Canal: 1825 Erie 1931, Huron '33, Michigan '49, Superior '54 Huge Schools in Lake Michigan • est. - up to 90% fish biomass

(Trout, Alewife, and lamprey)Coregonus Species Flock (have a lot of names, morphs and possible related species.)

Imprtant coregonus hoyi,, A deepwater Lake Michigan bloater chub; as gillnets are lifted to the surface, the fish's swim bladder expands lending to the name "bloater" chub. - Photo Credit: Dale Hanson (USFWS). Sea Lamprey invaded in 1940s and large chubs decline but small chubs, bloater increased in pop. 10 years later we have no more lake trout, alewife enters the system and bloaters have increased further, a couple of medium coregonus species left. Now these smaller fish are being targeted. 10 years later we have lost the other chubs, left with, alewife, lamprey, bloaters and humans. The bloater has begun to increase in size. Bloater Response is when they get brought up quickly from the water. The divergence may have been associated with depth and food access via open system niches. • switched from plankton to benthos • rapid change in gill raker morphology • fewer, shorter rakers in < 20 years • size increase • 1954 4.2 % > 9 in., 1966 38.2% Big Benthic Bloaters: hyp. Introgression w/remnant pops. • obs: bloater 72% female 1928 • 1969: 96% w/very low recruitment • 1968: Lake Superior < 50% female • "The taxonomic variability among C. hoyi is so great it represents a potpourri of Lake Michigan ciscoes and suggests, whether true or not, the consequence of introgressive hybridization of the Lake Michigan species." (Parsons and Todd 1974) • The Kiyi feeds on deepwater crustaceans such as Mysis relicta and Diporeia hoyi. Secondary prey items chironomids, calanoid copepods, clams and Daphnia species. typical measurements range between 100 and 200 mm, and weights of 10 to 60 g, but have been recorded in excess of 300 mm and 125 g. The bloater's average length at maturity is 18.3 centimetres

Osmotic Regulation Freshwater Cladocera

In freshwater cladocera, hyperosmotic regulation maintains the hemolymph hyperosmotic to the external medium. They drink water (Fox, 1952), must excrete excess water, and must supplement ions lost through excretion by obtaining them from food and by reabsorption of salts via the nuchal organ (Aladin, 1991). It has been determined that there is sodium and chlorine ion uptake in Simocephalus kept in a solution of sodium chloride; in this way, the hemolymph is maintained at a level hyperosmotic to the medium (Nimmo, 1966). According to Fritsche (1917), the freezing temperature (or the freezing point) in D. magna can be reduced from −0.20°C to −0.61°C. It is higher in younger specimens, and there is some relationship with nutrition and egg production, since it is higher in fed specimens than in starving ones. It decreases during prolonged parthenogenesis and is, on average, high in specimens with ephippia. Belayev (1950)found there to be considerable interindividual variation in temperature depression (Δ°) of the blood in Daphnia pulex (0.24-0.45°C), Eurycercus glacialis (0.36-0.39°C), and Bythotrephes longimanus (0.35-0.46°C). He concluded that D. pulex can regulate its osmotic pressure if the external salinity is not above 5‰. (osmo-regulation abilities)

Does Invasibility increase with lake trophic status?

Invasiveness x Invasibility • coexistence of E. affinis and native species is limited to more eutrophic Great Lakes habitats (realized niche) • hyp. osmoregulation stress on brackish water species entering freshwater is compensated for by high consumption 186 Non-indigenous species in the Great Lakes The homogcene... +++ "cryptic invasions" via solid ballast exchange Invasibility: hyp. ballast water exchange regulations exert strong selection pressure on potential invaders Invasiveness × Invasibility • obs. low salinity tolerance increases with food availability • 9. Dreissenid tolerant and N sensitive (NGL, spring). These taxa, including Stephanodiscus hantzschii f. hantzschii and Rhodomonas minuta, were intolerant of higher N concentrations. However, these tend to be spring taxa that occur in areas of the NGL with many dreissenids. Freshwater Biology (2017) 62, 366-381 • Phytoplankton data from Reavie 2009 USEPA Grant Report

An invasion cold spot

Is a hypothesis about how we get so much ballast water but small amounts of invasive. LS gets the most propagules and the most ballast discharge. Cold Spot Hypotheses - Physical Habitat • high profundal:littoral limits invasion potential Cold Spot Hypotheses • voyage too long? • low survival of propagules? Cold Spot Hypotheses • low disturbance such as floods, human activity. • low productivity Inadequate research effort

Petromyzon marinus

Key Areas of Concern: Lakes Huron and Erie Lake Huron Sea lampreys are found in more than 200 streams throughout the Great Lakes basin, yet more than half of the 275,000 adult sea lampreys reside in just nineteen streams. Ten of these nineteen streams are tributaries to Lake Huron and account for an estimated 32% of the basin-wide total of adult sea lamprey. Indeed, Lake Huron presents a unique challenge to sea lamprey control because it is fed by some of the most prolific sea lamprey producing tributaries in the basin. Due in large part to these major sea lamprey producing tributaries, sea lamprey abundances in Lake Huron have been above target for many years. To remedy the problem, sea lamprey control experts initiated a large-scale effort to treat the North Channel area of Lake Huron (including the St. Marys River) during 2010-2011, along with geographically expanded treatments in the northern parts of lakes Huron and Michigan in 2012 and 2013. While this increased treatment effort successfully reduced larval sea lampreys in the St. Marys River to an all-time low, the adult sea lamprey population remained frustratingly high. The good news is, the latest estimates suggest a trend in the right direction, which can likely be attributed to the increased treatments during the past three years. Lake Erie Despite intensified treatments over the past five years, Lake Erie sea lamprey abundances remain quite high. Record sea lamprey abundance was recorded in 2009 and, for the fourth consecutive year, in 2013, adult sea lamprey numbers in Lake Erie exceeded pre-control populations. The sea lamprey control program has undertaken several initiatives to determine the source of Lake Erie sea lampreys, including extensive surveys of Lake Erie tributaries, preliminary evaluation of the St. Clair and Detroit Rivers (known as the Huron-Erie Corridor) as a possible new source of sea lampreys, and interviews with U.S. commercial and charter fishers. Results from trapping efforts in the Huron-Erie Corridor in 2012 and 2013 reinforced suspicions that this system may be a significant source of sea lampreys in Lake Erie; investigations will continue in coming years. The total abundance of adult sea lampreys across the entire Great Lakes basin decreased from an estimated 511,000 during 2012 to an estimated 275,000 during 2013. Five-year running means of annual, lake-wide adult sea lamprey population estimates for each Great Lake and all lakes combined, 1980-2013. FIGURE: J. BARBER, USFWS; G. BRAVENER, DFO; J. ADAMS, GLFC/USGS

Perch diet in relation to a hypoxic zone

Note: most Bythotrephes were in the hypolimnion during the day (DVM) Some individuals appeared to dive into the hypoxic hypolimnion to feed on benthic prey Note site A had a relatively thin hypolimnion obs. benthic to pelagic diet shift in the middle of the hypoxic zone Trawl data also indicate vertical migration to avoid hypoxia and night movement back to hypolimnion following turnover Trawl data indicate migration to shallows during hypoxia prey consumption decreased at hypoxia peak (mass of stomach contents) Prey consumption decreased at hypoxia peak Fish condition did not change

General Effects of Dreissena

Pelagic to Benthic Energy Shunt transparency increases (up to 85%) chlorophyll a declines (up to 40%) phytoplankton biomass declines (40-80%) more benthic filter feeders means less energy in the plankton part of the food web. We see a general movement of energy down through the food web.

The rise of the profunda morph

Phenotypic Variation Morphology: lower, less convex shell, elongated siphons First discovered in Lake Erie >28 m Rapid Evolution? Meaning in this lifetime Developmental Plasticity? Or just the ability to take multiple forms during development obs cold temperature induced deep-water shell morphology (8 vs 18°C) mechanism not investigated Found colder waters can produce deeper water mussels which is an environmentally induced response. However, the Cheboksary Reservoir does not stratify (cold water only during winter) other possibilities? Other options to look into are possible BUT No evidence of water movement, food concentration, or substrate effects (Cheboksary profundas on sand/gravel with high current velocities) Role of Pressure? Has a larger role in colder and more so deeper waters. And this is hard to do. obs. pressure effects can influence bivalve growth and development Evolutionary history of the profunda morph • hyp. deepwater morph ancestors forced to shallow water estuaries by salinity increases in Euxine Lake/ Black Sea. --- So what happened biogeographically? It is possible the old morph evolved as a deep water morph but was moved into shallow water due to salinity increase. • truncation of the Black Sea fluvial drainage by glacier advances, so reduced the freshwater hydrologic intake, there was the creation of a "Euxine Lake"--- as we have more and more melting moving into fresh water having an influence on the salinity of these waters. Indicating the morphs are a response of its history, so this deep water form evolved during the Pleistocene but influenced by the environment. (Today is the Caspian sea aka wanna be the largest lake in the world). • phenotypic plasticity - 2 possibilities • differential expression of alleles in differing environments • gene regulation - genes that produce deepwater morph can be turned on and off i.e. epigenetics Indicating the profuna morph didn't evolve in Lake Erie but that it's epigenetics were recognized in lake Erie and in the reservoir in Russia

pre, current, post dreissena

Pre-Dreissena • nearshore was a P source (weak retention) for offshore productivity Dreissena effect on Seston Particle Size (increases - see figs from past lectures) • effect on offshore transport potential Post-Dreissena Nearshore Shunt • increased nearshore nutrient retention • allochthonous P - seston • metabolic wastes, pseudofeces • increased bioavailability of P + loss of energy use to produce shells and biomass

Name difference and similarities between quagga and zebra mussels

Quagga physiological advantages over Zebra in the Great Lakes • lower respiration rates could be a more efficient use of their habitat • more energy, faster growth The quagga has more effiecient respirations and use of food and then larger in size therefore higher reproduction compacity, which could explain them out competing zebras Gametogenesis minimum temperatures is the temp they form eggs or sperm. And could explain the reasoning also for differences n success. During the varying season the quagga are able to maintain in those very low temps *important finding They cant hybridize its been tried

IN the senica lake the dripoeria has perisisting and the dressenia is still low. So maybe these very narrow lakes with lots of rivers feeding it with a better connection the terrestrial ecosystem influences the mussel success. Some declines in L. Superior, particularly in the eastern half natural variation?

Response of L. Ontario benthivores • diet shift and population collapse in slimy sculpins • from Diporeia + Mysis to mixed Mysis and soft-bodied benthos • still selects available Diporeia (strong preference) • probable continued losses w/o Diporeia • Cottus cognatus Response of L. Ontario benthivores • diet shift and population collapse in lake whitefish • from Diporeia + Mysis to mixed Mysis and soft-bodied benthos, + gastropods, Sphaeriidae, + Dreissena (shell-crushing stomach) • probable continued losses w/o Diporeia • oregonus clupeaformis Post-invasion diet shift - L.MI • total food consumed did not change • non-mollusk benthos consumption down 46-96%, gastropod and Dreissena up • post-Dreissena mass down 38% Potoven and Madenjian 2008. N.Am.Fish.Man. 28: 308-320 Post-invasion diet shift - L.MI • total food consumed did not change • non-mollusk benthos consumption down 46-96%, gastropod and Dreissena up • post-Dreissena mass down 38%

Major influence seen in changes of diet Altogether, 1,624 amphipods (52.2%) exhibited at least one parasitic infection. The reaction to the pathogens varied greatly from differentiated and melanized hemocytic encapsulations in tissues adjacent to parasites to no obvious or negligible responses. A microsporidian and a haplosporidian elicited considerable tissue destruction and host immune response (Fig. 3).

Response of L. Ontario benthivores Cottus cognatus • diet shift and population collapse in slimy sculpins • from Diporeia + Mysis to mixed Mysis and soft-bodied benthos • still selects available Diporeia (strong preference) • probable continued losses w/o Diporeia Response of L. Ontario Benthivores • diet shift and population collapse in lake whitefish • from Diporeia + Mysis to mixed Mysis and soft-bodied benthos, + gastropods, Sphaeriidae, + Dreissena (shell-crushing stomach) • probable continued losses w/o Diporeia • We saw a shift in diet, they are able to eat this stuff due to the muscular stomach so they can crush the shells. Post Invasion Diet Shift - Lake Michigan • total food consumed did not change • non-mollusk benthos consumption down 46-96%, gastropod and Dreissena up • post-Dreissena mass down 38% In general soft body forms and crustaceans are going down

Chironomidae Tubes are able to mine O2?

Seasonally sampled cores of burrowed sediment containing chironomid larvae were collected from Cooking Lake, Alberta, and analyzed to (1) assess and establish the typical burrowing behavior and burrow architecture of chironomid larvae; (2) record micrometer-scale geochemical profiles of O2, H2S, and pH in the uppermost sedimentary layers throughout a seasonal cycle; and (3) link changing geochemical conditions to changing burrowing behaviors. We observed that the larvae lived in soft, water-saturated sediment, maintained by open burrows accreted by the animal's mucous. Chironomid-larvae burrows were small and Y-shaped (e.g., Polykladichnus-like) or Y-shaped with basal branches (Thalassinoides-like) and were 20 cm deep. The larvae moved up and down from the oxygenated zone ("sounding" behavior) to exploit food in suboxic and anoxic sediment. Geochemical analyses showed that H2S was present in the pore waters to within 1.5 mm of the sediment-water interface during the summer, when lake-bottom algae and cyanobacteria generated sufficient O2 to drive the oxic-anoxic redoxcline into the sediment. In the winter, the H2S front extended upward into the water column owing to the cessation of algal and cyanobacterial activity. The prevalence of H2S results from a combination of high-dissolved-sulfate concentrations in the lake and the abundance of microbial biomass that fuels an active subsurface population of sulfate-reducing bacteria. Interestingly, burrowing behavior was not linked to seasonal changes in the sediment chemistry. This is in part due to the ability of chironomid larvae to exploit oxygen islands in the sediment: in the winter, the chironomid larvae harvest their oxygen from the uppermost photosynthetic layer in otherwise O2-impoverished sediments.

Semelparity

Semelparity and iteroparity are two classes of possible reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characterized by multiple reproductive cycles over the course of its lifetime. MDN = Marine Derived Nutrients "Contemporary Evolution" of Great Lakes Chinooks • feral pops and "rampant" wild reproduction • Canadian streams initially colonized by "strays" • subsequent reproductive isolation + selection • continued stocking will swamp out local adaptations • how does this mesh with native species management?

Resource limitation relaxed by invasive species?

The Lake Erie watersnake was removed from of the list of federally endangered and threatened species on August 16, 2011. This species was originally listed as a federally threatened species on August 30, 1999." The Lake Erie water snake subspecies, Nerodia sipedon insularum, was once endangered, but now benefits from the introduction of the round goby, an invasive species, which now comprises up to 90% of its diet. The Northern Water Snake is extremely common over most of its range and is frequently seen basking on stream banks, from which it dives into the water at the slightest disturbance.

Shortjaw Cisco (Coregonus zenithicus)

The Shortjaw Cisco (Coregonus zenithicus) is a widespread species in the Salmonidae subfamily, Coregoninae. It has the following characteristics: Often silver in colour, with olive or tan on the back and white on the stomach; however, colour variations occur across their distribution; Elliptically shaped body that is laterally compressed and covered with large, smooth scales; Mouth is small and toothless; lower jaw is usually shorter than, or even with, the upper jaw; Gill rakers number between 32 and 46 (comb-like structure on the inner surface of the bony arch supporting the gill), fewer than most other cisco species; Gill rakers are moderate or short in length, compared to other cisco species; In Ontario, maximum length is highly variable; ranging from 400 mm (Lake Nipigon) to less than 100 mm (White Partridge Lake); Weight is generally less than 300 g, although exceptionally large specimens can reach 1 kg; and Little is known about the growth of the species in northern and prairie lakes, with the exception of Barrow Lake, Alberta, where individuals have been reported greater than 400 mm in length. Habitat The Shortjaw Cisco has a widespread distribution in Canada, ranging from the Laurentian Great Lakes throughout central Canada to the Northwest Territories. In the Great Lakes, it is currently found in lakes Superior and Nipigon and has been reported in Lake Huron after not being collected since 1982. It is believed to be extirpated from lakes Michigan and Erie, and is in serious decline in lakes Superior and Huron. In addition to the Great Lakes, Shortjaw Cisco have been reported in 10 other lakes in Ontario. In the Prairies, Shortjaw Cisco have been reported in numerous lakes in Manitoba and Saskatchewan (Lake Athabasca, Reindeer Lake, Lake Athapapuskow, Clearwater Lake, Lake Winnipeg and George Lake) and one lake in Alberta (Barrow Lake). In the Northwest Territories, it has also been documented in Great Slave Lake and Great Bear Lake. Most life history information has been collected from the Great Lakes, with much less understanding of history and habitat requirements from other locations. The Shortjaw Cisco generally inhabits the deep waters of large lakes, between 55 and 180 m. In Lake Superior, seasonal depth differences have been recorded including movement into shallower water during spawning. In Lake Nipigon, it inhabits depths of 10 to 60 m, and occasionally deeper. This species usually spawns in the fall, however spring spawning has also been reported. Fecundity is likely similar to other deepwater ciscoes: 3,200 to 18,800 eggs depending on fish length. Eggs are deposited on the lake bottom and left unattended to develop for three-to-four months. Females grow faster, larger and heavier, and live longer than males. Age of maturity varies widely by location, from two years (Barrow Lake), to four years (Lake Winnipeg) to five or six years (Great Lakes). Its lifespan was previously estimated between 10 and 13 years; however, recently Shortjaw Cisco have been aged up to 25 years old in lakes Superior and Nipigon. The Shortjaw Cisco is prey for Lake Trout (Salvelinus namaycush) and Burbot (Lota lota). Their diet includes the Opposum Shrimp (Mysis diluviana) and the Scud (Diporeia spp.), along with copepods, cladocerans and aquatic insect larvae. Threats In the early 1900s, commercial overfishing in the Great Lakes had a negative impact on Shortjaw Ciscos. More recently, habitat degradation (including eutrophication), and competition with/predation from exotics, such as the Rainbow Smelt (Osmerus mordax), Alewive (Alosa pseudoharengus) and Sea Lamprey (Petromyzon marinus) have imposed additional stresses.The historical and present abundances of the Shortjaw Cisco in the Prairies and the Northwest Territories are not known. Consequently, there is no direct evidence of its decline in these areas, and defining potential threats is difficult. Nonethless, many of the same types of threats may apply. http://www.dfo-mpo.gc.ca/species-especes/profiles-profils/kiyi-eng.html Description The Kiyi (Coregonus kiyi kiyi) is among the deepest water forms of cisco species found in Canada. It is a member of the Salmonidae family and has the following characteristics: laterally compressed body with large eyes that comprise 22 to 26 per cent of the head length; terminal mouth with lower jaw usually extending beyond the upper jaw; mainly silver in colour with some pink and purple iridescences; long paired fins; sexually mature between ages two and five years; and typical measurements range between 100 and 200 mm, and weights of 10 to 60 g, but have been recorded in excess of 300 mm and 125 g. Habitat The Kiyi is endemic to all of the Laurentian Great Lakes except Lake Erie. The Upper Great Lakes population (Coregonus kiyi kiyi) is believed to currently exist only in Lake Superior. Believed extirpated, it was last recorded in Lake Huron in 1973 and in Lake Michigan in 1974. The Lake Ontario population (Coregonus kiyi orientalis) is considered extinct, last recorded in 1964. Kiyi appears to be widely distributed in the deep waters of the offshore (generally most abundant at depths of 150 m) making up a significant proportion of the fish community in Lake Superior. They are also found in reduced numbers in the shallow waters of the nearshore. Kiyi move to shallower water depths at night, typically less than 50 m, in search of their prey. Little is known about the habitat preferences and life history of the Kiyi. It lives in a clear, cold-water environment at depths ranging from 10 m to 305 m, with peak abundances found at depths between 130 to 150 m. Kiyi have been collected over lake bottoms of clay and mud substrates. Spawning generally occurs in the late fall at depths between 91 and 168 m. The age of maturity is between two and five years. The maximum known age for females is 22 years, and 16 for males. The Kiyi is prey for Burbot (Lota lota) and deepwater forms of Lake Trout (Salvelinus namaycush). Kiyi eggs may also provide a prey source for other fish, including Lake Whitefish (Coregonus clupeaformis). The Kiyi feeds on deepwater crustaceans such as Mysis relicta and Diporeia hoyi. Secondary prey items chironomids, calanoid copepods, clams and Daphnia species. Threats Commercial overfishing of Kiyi was likely the cause of its decline in lakes Huron, Michigan and Ontario. Remaining Kiyi populations in lakes Huron and Ontario likely have competed with, or have been preyed upon by, introduced fish species such as the Sea Lamprey (Petromyzon marinus), Alewife (Alosa pseudoharengus) and Rainbow Smelt (Osmerus mordax). Other issues, including degraded water quality (from the continuing pressures of contaminant and nutrient inputs in the Great Lakes) are also ongoing, with likely impacts on Kiyi survival and habitat. Climate change has been identified as a possible factor that could worsen the situation in the future. Lastly, certain pathogens, particularly viral hemorrhagic septicaemia (VHS), have the potential to generate mass mortality in a variety of fish species. Detected in Lake Superior watershed in 2010, future outbreaks of VHS could decimate the remaining Kiyi population.

Management of Alewife Using Pacific Salmon in the Great Lakes: Whether to Manage for Economics or the Ecosystem?

The combined destructive effects of overfishing, habitat destruction, and invasive species, especially alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) led to the loss of the native top predator lake trout (Salvelinus namaycush) from most of the Great Lakes by 1960. Alewife populations then exploded, creating nuisance die-offs. Public demands for action, coupled with control of sea lamprey, allowed fishery managers to consider stocking Pacific salmon to control alewife and establish a recreational fishery. This effort was successful, reducing alewife numbers and creating a recreational fishery that is estimated at $7 billion annually. This fishery management regime may no longer be viable as new invasive species continue to alter the ecosystem. Fishery managers face an interesting dilemma: whether to manage in the short term for a popular and economically important sport fishery or to embrace ecosystem change and manage primarily for native fish species that appear to be better suited to ongoing ecosystem changes. Such dilemmas occur in great lakes around the world as fishery managers seek to balance economic pressure with changes in their respective ecosystems, often brought about by invasive species.

Disappearing Diporeia What is causing these declines?

The group determined that the doughnut was formed when big winter storms kicked up sediments along the southeastern shore of the lake. There, Michigan's biggest rivers drain a watershed rich in phosphorus and other nutrients from cities and farms. Those nutrients settle in the lake's sediments until storms stir them up. Then, suspended in the water column, they begin circulating in a slow-moving gyre that flows from Grand Haven in the north to Chicago in the south. That gyre creates a Thanksgiving feast for phytoplankton. "We saw that with each storm, you get a ring, and it can persist for weeks or even months," says Kerfoot. What is causing these declines? REVIEW - Diporeia hoyi • historically ~ 70% benthic biomass >30m Declines in some sites were relatively gradual and resulted from poor juvenile survival food limitation? We have seen averages go down while others are small changes, where poor juvenile survival could be occurring from food limitation. Food interception by Dreissena? Because of excess filtering because of locations where quagga mussels are doing the best is also where dressenia are doing the worst. • obs. declines greatest in 30-50 m where D. bugensis abundance increases were greatest • obs. declines greatest in northern part of lake where Dreissena abundances are greatest However, Diporeia declined in some places far removed from quagga mussel beds • Declines in some sites were rapid and included all ages • some sort of toxin associated with Dreissena? • obs. pseudofeces exposure can reduce Diporeia survival AbstractThe deepwater amphipod Diporeia hoyi has disappeared from Lake Erie and much of Lake Ontario at depths < 80 m. This amphipod had supplied 20 percent of the fisheries energy budget in the Great Lakes. The exotic mussel Dreissena bugensis now forms most of the benthic biomass above 60 m depth, but Diporeia is absent over large areas where Dreissena are rare. The filamentous bacterium Thioploca ingrica is now common at many sites between 30 and 40 m where Diporeia has disappeared. Fisheries and Oceans, Canada, investigated the causes of the decline by examining the sediment chemistry, bacterial production and conducted sediment bioassays using Diporeia, Hyalella and Microtox® Microtox® showed no evidence of toxicity in sediments now devoid of Diporeia. Amphipod survival and growth was greatest in sediment that rapidly lost its Diporeia population in 1993. Presence of Thioploca had no effect on Diporeia survival. Hyalella was more sensitive than Diporeia to test sediments and to filtered water from mussel cultures. Sediment from sites with dense Dreissena populations had lower Diporeia survival. A diet of mussel pseudofaeces caused significantly lower survival in both Hyalella and Diporeia. The exact mechanism causing lower survival is currently unknown and may be related to a nutritional problem or associated waste metabolites. Thioploca is a sulfide oxidizer that has taken the place of diporiea in the east end of lake Ontario. Anerobic degredation because of the development of this cyanobacteria has become a dense mat covering the surface. Has been seen in chyuoga, champlaign, etc.

Bioaccumulation of selected halogenated organic flame retardants in Lake Ontario

The trophic magnification of polybrominated diphenyl ethers (PBDEs) and selected non-legacy halogenated organic compounds (HOCs) was determined in the food web of Lake Ontario. 28 Br3-Br8-PBDEs and 24 HOCs of which 10 had not been targeted previously were analysed. Average concentrations of Σ28PBDEs in fish ranged between 79.7 ± 54.2 ng/g lipid weight (lw) in alewife (Alosa pseudoharengus) and 815±695 ng/g lw in lake trout (Salvelinus namaycush). For invertebrates it was between 13.4 ng/g lw (net plankton; >110 μm) and 41.9 ng/g lw in Diaporeia (Diaporeia hoyi). Detection frequency (DF) for HOCs was highest for anti-Dechlorane plus (anti-DDC-CO), 1,3-diiodobenzene (1,3-DiiB), tribromo-methoxy-methylbenzene (ME-TBP), allyl 2,4,6-tribromophenyl ether (TBP-AE), pentabromocyclododecene (PBCYD), α+β-tetrabromocylcooctane (TBCO), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE), and pentabromotoluene (PBT) (DF = 100% in lake trout). Tetrabromoxylene (TBX), dibromopropyl 2,4,6-tribromophenyl ether (TBP-DBPE) and syn- DDC-CO were also frequently detected in trout (DF=70-78%) while 2,3,4,5,6-pentabromoethyl benzene (PBEB) was detected only in plankton. Several HOCs were reported in aquatic biota in the Great Lakes for the first time in this study including PBCYD, 1,3DiiB, BATE, TBP-DBPE, PBT, α+β-TBCO, and ME-TBP. The Br4-6-BDEs (-47, -85, -99, -100, -153 and -154) all had prey-weighted biomagnification factors (BMFprey-weighted) values >6 while BMFprey-weighted values for Br7-8-BDEs were < 1. The highest BMFprey-weighted values of non-PBDEs were for TBP-DBPE (10.6±1.34) and ME-TBP (4.88±0.60) while TBP-AE had a BMFprey-weighted value of <1. Significant (p <0.05) trophic magnification factors (TMFs), both positive and negative

Some declines in L. Superior, particularly in the eastern half natural variation?

The whole pattern (all GL) itself is the diporea is going down, it is not obvious. Lake superior is the main place in the future to still find diporea Status of Lake Superior Starting to slowly see sites being added with the invaders, and it's now a question of when will it pick up. Including the apostle islands, bc the currents and warm waters and sediments coming through the Duluth port.

What is being inherited?

We predicted that under freshwater conditions VATPase activity would be elevated in the freshwater populations relative to their saline ancestors, to absorb ions from very dilute environments (Fig. 2B). We also predicted higher Na/K-ATPase activity in saline than in freshwater populations, as Na/K-ATPase might play a more important role for ion uptake in saline environments (Fig. 2A). Vacuolar-type H+ -ATPase (V-ATPase) is a highly conserved evolutionarily ancient enzyme with remarkably diverse functions in eukaryotic organisms. V-ATPases acidify a wide array of intracellular organelles and pump protons across the plasma membranes of numerous cell types. V-ATPases couple the energy of ATP hydrolysis to proton transport across intracellular and plasma membranes of eukaryotic cells. It is generally seen as the polar opposite of ATP synthase because ATP synthase is a proton channel that uses the energy from a proton gradient to produce ATP. V-ATPase however, is a proton pump that uses the energy from ATP hydrolysis to produce a proton gradient. obs. VATPase activity at low salinity increased following freshwater invasion Selection experiments showed that this response can be rapid (12 generations)

Sander vitreus glaucus blue pike

hyp. deep, cold water divergence • est. 100,000,000 in lake circa 1900 • 20,000,000 lbs annual harvest • last reported spawning 1954 "After nearly a year of study, it turns out that the extinct Lake Erie blue pike really is extinct ... the finding came from Carol Stepien, a Case Western Reserve University researcher." Why Blue? Yu et al. 2008.Env.Biol.Fish 82:51-58 • "sandercyanin" obs. blue biliproteins function in crypsis in other organisms • deepwater crypsis? • blue biliproteins also provides the green color in + carotenoids • hyp. loss of reproductive isolation resulted form anthropogenic habitat change hybridization and "genetic erosion" of blue pike via introgression • ob.s blue perch from Lakes Ontario and Erie (web sourced photos - unverified locales) • i.e., genetic factors contributed to extinction Lake Erie, because of its shallowness and the fertility of its drainage basin, is the most productive of the Laurentian Great Lakes. The fish community is diverse (114 species representing 24 families) and is dominated by mesothermal and warmwater species. Although commercial fish production has been fairly consistent (average annual yield of 23,000 metric tons since 1915) there has been a dramatic change in species composition during the last 150 yr. Lake sturgeon, lake trout, lake herring, lake whitefish, sauger, and blue pike have virtually disappeared. Commercial production of medium-priced species such as yellow perch and white bass has increased and lower-valued species such as rainbow smelt, alewife, and freshwater drum have become more dominant in the fishery. The cultural stresses deemed largely responsible for these changes are, in approximate order of effect, an intensive commercial fishery, nutrient loading, the introduction of nonnative species, tributary and shoreline restructuring, erosion and siltation, and the introduction of toxic materials. The effects of these stresses on the environment and species composition are discussed.The current status and future of the remaining commercial species are considered in the light of past and present effects of the cultural stresses. The joint efforts of the United States and Canada to improve water quality and to control and reduce nutrient loading should lead to an improvement in the environment in the near future. Lake Erie is well suited for the production of valuable percid species but unless a strong effort is made to regulate exploitation the future of the commercial fishery is precarious.

Invasional Meltdown Model

is a positive feedback mechanism, An example of direct facilitation is the provision of biodeposits and shelter by an introduced mussel for an introduced detritivore. An example of indirect facilitation is the reduction of piscivores by an introduced parasite (e.g., sea lamprey), paving the way for invasion by a planktivore (e.g., alewife). Invasion; Direct facilitation are effects that directly benefit another invader (e.g. More nutrient, shelter etc.) Indirect facilitation are effects that reduce an invaders enemies or enhances its prey. Invasional Meltdown The system state can change based on the influence of the invaders. Therefor invasion into an ecosystem happens more easily as number of invaders increases.

So how does this happen? i.e., what is the mechanism? Four conditions:

the traits must vary, Fitness Must Vary among trait variants in the environment where selection is occurring The trait must be Heritable and Mating Opportunities must exist The survivors matter most

Invasiveness

traits that affect the probability of a species becoming invasive (Remember the zebra invaded before the quagga and this is not random. This seemed to happen in waves by the fast and then slow but compeptive species. Invasiveness of Zebra and Quagga Mussels obs. timing to maximum density is much shorter for zebra mussels (2-4 yrs vs 6-19) obs. zebra mussels invested more energy in eggs makes them more invasive hyp. more easily vectored, that flat bottom is a zebra mussle which allows them to stick more easily and stay stuck which is more zebra then quagga. Look at the byssus which zebra threads faster and tighter.)

Carbon Uptake by Cladophora

• carbonic anhydrase • catalyzes hydrolysis of HCO3 to CO2 • + proton "pumping" HCO3 + H CO2 + H2O Carbon uptake in the green macroalga Cladophora Glomerata (L.) Kütz. from the brackish Baltic Sea was studied by recording changes in pH, alkalinity, and inorganic carbon concentration of the seawater medium during photosynthesis. The use of specific inhibitors identified three uptake mechanisms: 1) dehydration of HCO3 into CO2 by periplasmic carbonic anhydrase, followed by diffusion of CO2 into the cell; 2) direct uptake of HCO 3 via a 4,4 -diisothiocyanatostilbene- 2,2-disulfonate-sensitive mechanism; and 3) uptake of inorganic carbon by the involvement of a vanadate-sensitive P-type H -ATPase (proton pump). A decrease in the alkalinity of the seawater medium during carbon uptake, except when treated with vanadate, indicated a net uptake of the ionic species contributing to alkalinity (i.e. HCO 3, CO32, and OH) from the medium, where OH influx is equivalent to H efflux. This would suggest that the proton pump is involved in HCO3 transport. We also show that the proton pump can be induced by carbon limitation. The inducibility of carbon uptake in C. Glomerata may partly explain why this species is so successful in the upper littoral zone of the Baltic Sea. Usually, carbon limitation is not a problem in the upper littoral of the sea. However, it may occur frequently within dense Cladophora belts with high photosynthetic rates that create high pH and low carbon concentrations in the alga's microenvironment.

Why does D. polymorpha lack a deepwater morph?

• hyp. speciated in rivers (N. Paratethys) • entire evolutionary history in shallow water

Osmerus mordax

• introduced in Crystal L. MI 1912 (landlocked Maine strain) • Smelt runs- spring night spawners 4.4'C young eat zoops, adults eat Mysis, insects, small fish

Invasiveness -Traditional Model

• jump dispersal • phenotype-habitat matching • and/or broad physiological tolerances One of the things that allows for success is that we move them from nature enemies and diseases and other top down control mechanisms. They can mainly persist by having a broad ecological tolerance.

Quagga physiological advantages over Zebra in the Great Lakes

• lower respiration rates could be a more efficient use of their habitat • more energy, faster growth The quagga has more effiecient respirations and use of food and then larger in size therefore higher reproduction compacity, which could explain them out competing zebras Gametogenesis minimum temperatures is the temp they form eggs or sperm. And could explain the reasoning also for differences n success. During the varying season the quagga are able to maintain in those very low temps *important finding

Drivers of Diversification aka ultimate source of new genes

• mutations • environmental change • organismal interactions Phenotypic Plasticity which is a malleable phenotype a species ability to response and it's environment. Such as predator or predator free environment

Invasibility - "Darwin's Naturalization Conundrum"

• the presence of congeners influences invasibility • (probability of naturalization) • pre-adaptation vs competition • Naturalized species aka established: • Ecosystem matching as a result of preadaptation • Niche overlap vs preadaptation A Matter of Scale? Smaller Spatial Scales hyp. species interactions are more important competitive exclusion (increases with similarity) clustering of enemies, etc. Larger Spatial Scales environmental filtering is more important similar species succeed in similar environments greater potential for coexistence of related taxa Terrestrial vs Freshwater Space • are freshwater habitats analogous to islands? • Being from somewhere else on the same continent or being from a different continent? • Locations with various levels of connectivity • Example is that the big lakes little lake and freshwater streams are all distinctly apart and interconnected by those streams and considered to apart of the landscape and apart of the ecosystem. Fish rarely get moved around unless swimming or by the egg placement. Put that next marine systems which are connected o a high degree. • Phylogentic Scale? • how similar are species, genera, families, etc.? • Ancient vs. divergences • The issues with Darwin's conundrum is taxonomic. The ability to study these Darwinian phenomena is limited. It is possible to be so distant to be in a different family but still have the same potential to inhabitant the same location. So in this in understanding it is still coarse. • Herculated tasks.

Fast facts Diporeia Biology

• two year life cycle • spring (pre-birthing) migrations • move back to deep water when shallows warm Diporeia hoyi • burrows in upper 2 cm • basic diet - decomposer bacteria • prefer diatoms when available • lipid content increases in spring and fall