aquaculture test 2
Trickle tower
(type of biofiltration). Degassing nitrogen and other harmful gases. Oxygenates the water and removes ammonia
Bead filter
(type of biofiltration). Water enters through bottom, flows upward so solids drop out or are trapped. Periodically backwashed to remove solids.
feeding cage culture
- Floating pellets (low current, floating cage) - Sinking pellets (more current, submersible) Need to think about access to fish (dock, boat, remote feeding)
Hypothalamus -> pituitary -> gonad
- external stimuli triggers hypothalamus - hypothalamus releases gonadotropin releasing hormone - GnRH triggers pituitary to release gonadotropins (GTH1 and 2) - GTH 1+2 stimulate final maturation and ovulation in gonad
Problems with cage culture
-Fouling (plant and debris build up on net, makes net heavier and more susceptible to current. Needs to be regularly cleaned) -Poaching -Waste deposition
cryopreservation procedure
1. collect sperm 2. place sperm in buffer 3. place sperm in cryoprotectant 4. freeze sperm 5. thaw immediately prior to use 6. activate sperm after mixing with eggs
steps of artificial insemination
1. get fish into temp and photoperiod conditions that mimic spawning season 2. apply additional hormone treatments if necessary 3. closely monitor fish for spawning readiness 4. collect eggs and sperm 5. incubate 6. remove dead eggs promptly
What are the 7 steps of FW mussel culture
1. remove glochidia from gravid female 2. infest host fish 3. collect juvenile mussels 4. prepare sediment and algae culture tanks 5. transfer juveniles to culture troughs 6. maintain water quality and food supply 7. rear to release size
3 types of waste solids
1. settleable 2. suspended 3. dissolved
Green water culture
Adding live (micro)algae to system. Phytoplanktonic algae leads to improved growth and survival. The zooplankton eat algae and enriches HUFA
Submersible cage
Advantage in large storms, withstands wind and waves better than floating design. Feed through passage at top of net. Buoyancy from rubber floats
What is foam fractionation/protein skimming?
Air bubbled at bottom of a closed column of water. Foam created at air water interface. Solid particles attach to the bubbles surfaces (forming foam). More foam created = higher the salinity and pH
what are some commercial substitutes for live algae
Algae paste/flake. It's high in HUFAs and the zooplankton consume it, improving nutrient content
gastrula
An embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.
Interdisciplinary culture
Animals used to provide manure for pond fertilization. Low cost, but requires pond seining and maintenance.
Conservation aquaculture
Benefits from commercial aquaculture because of culture techniques, reproductive techniques, reduction of disease and stress, and developed technologies
Which (cage or pen) has rigid sides or rigid top
Cage has rigid sides Net has rigid top
artificial induction
Common dosing: - Priming dose (10-20% of required dose) - Resolving dose 12-24 hours later, 80-90% of required dose
What must be considered when choosing cage culture design
Conditions at the site (current, waves, distance from shore), balance of cost and safety, ease of handling
what kinds of records should be kept for a hatchery
Costs (feeding, energy, labor, maintenance) Water (issues, flow rate, temp) Fish (weight, survival, feed, dates) Mortality (#s, cannibalism, predation) Food and diet (cost, rate, FCR) Disease (occurrence, kind, results)
RAS: Solids
Feed not eaten and excreted waste. Bacteria breaks it down and while doing so consumes O2 and generates ammonia
Larval feeding strategies
Fit food to mouth size, digestible (fish needs appropriate enzymes to digest food), eliminate live food ASAP
what is a biofloc
Flocs (aggregates) of algae, bacteria, protozoans, organic matter (uneaten food, feces) create a matrix/community
Gastropods
Highly diverse, snails use gills. Hard to reproduce. Diet of algae
Off flavor in RAS
Is a common problem. It's the muddy flavor in fish due to cyanobacteria, algae, actinomycetes that produce a metabolic compound. Purge by transferring fish to a separate system
When is the best time for hormone injections
Late vitellogenesis to final maturation. Timing of hormone injections is important to efficiancy
Quarantine protocol
Must quarantine all new fish to the facility. Kept in separate system with different water and equipment. Hands, equipment, and footware are disinfected
Cage and net pen culture
Origin: holding fish in a cage or pen. Now: culture of fish in confined conditions
Ozonation
Ozone has contact time with water, sterilizes water. Problematic for workers and cultured animals because it's very toxic
Pond culture of juvenile mussels
Start with a 2-4 week water acclimation period. Whole process takes about 18-20 months. Use aquashade to reduce light penetration and therefore reduce algae growth which could clog gills
Re-introduction of FW mussels
Tag them with dental cement and release in lower end of drainage (hydrologically stable), need habitat with floodplain connectivity
epiboly
The expansion of one cell sheet over other cells
Neurulation
The first step in the development of the nervous system
Gastropod reproduction
They're temp dependent, have low fecundity. Cannot disrupt afterwards for several months. Lay eggs
Artemia
Type of zooplankton (sea monkeys). Small and slow moving. Very common in FW but works in SW too
O2 injection
Used for high biomass load. Sources from 1. high pressure O2 gas 2. Liquid O2 3. On-site O2 generator
Female reproductive cycle
Vitellogenin (in liver, provides yolk in egg) combines with Ca2+ (in blood) to make Vg+Ca which goes to the ovary
Settleable solid waste
Waste accumulates on bottom. Can be removed by drains, a settling tank, or a mechanical filter
Stocking and re-introduction in conservation aquaculture
When and where is important. Age and size want as young as possible. Want to minimize hatchery selection and maximize survival in wild. Mark released fish to identify hatchery origin and year class, along with survival and growth rates
zygote
fertilized egg of one cell
mixed multiple batch
fish of different ages and sizes mixed together. Requires labor for sorting through sizes. Maintain biomass near max capacity.
multiple batch
fish spawn over time, raise multiple batches
Four different cage culture designs
fixed, floating, submersible, submerged
Floating cage culture
floating unit, flexible net suspened underneath. Has two nets: inner (cultured fish), outer (keeps predators out)
how to get rid of dissolved waste solids
foam fractionation or partial water exchange
what must be done before starting a conservation aquaculture practice
genetic assessment of existing pop(s) -> determine quantity and distribution of genetic variation in species, estimate historical levels of isolation and gene flow, identify unique gene pools
Genetic management after starting conservation aquaculture program
genetic monitoring of natural and captive populations, use large #s for captive breeding, selective mating to avoid inbreeding, minimize captivity time, separate maintenance of stocks
what does an egg need
good water quality, minimal disturbance, low light intensity
Types of mechanical filtration
gravel/sand filters, bag filters, cartridge filters
what are the two types of bioflocs
greenwater and brownwater
What are some early live foods
greenwater culture, zooplankton, microworms, planaria
Spawning techniques
hastening maturation (provide high-quality diet, optimal growing conditions), manipulating natural conditions to trigger spawning (photoperiod, temperature)
What are the three larger fish developmental stages
hatching, yolk sac fry, swim up fry
why is conservation aquaculture done
help severely diminished populations, isolated populations/species, unique species, and lack of natural recruitment
HUFA
highly unsaturated fatty acids
Causes of species declines
human-induced changes (habitat change, pollution, overexploitation), random catastrophic events
Teleost endocrine theory
hypothalamus with GnRH -> Pituitary with GTH 1 and GTH 2 (hormones for final maturation and release) -> Gonads (ovary/testes)
Pathways to invasion
illegal aquarium releases, accidental bait releases, intention releases, aquaculture escapes
what is a biofloc system
intensive, recirculating system. Alternate approach to waste management
Glochidia
larval mussel form. Attach to fish like a parasite, usually at gills. Transform on the fish then are dropped off
look at graph of hatchery phases
lecture seven slide 3
Is more pumps or less pumps better
less
Spindle-shaped submersible cage
looks like a modified fyke net, can be floated and rotated for cleaning. Can sink with weights in bad weather
what are conservation aquaculture goals
maintain genetic diversity, minimize hatchery selection processes (reduced stress response, aggressive feeders)
Goal of conservation aquaculture
maintain total genetic diversity within population genetic diversity and differences among populations
blastula
many cells
what are commercial aquaculture goals
maximize specific traits in fish
Fine suspended solid waste
may contribute 50% of suspended solids. Increases O2 demand and can cause gill irritation and damage. Removed from foam fractionation or protein skimming
Short lived species conservation aquaculture
may require immediate action to prevent extinction. Benefits: if culture is successful, can produce many fish in a short amount of time
Fertilization in artificial induction
mix eggs with sperm with or without water. Eggs get sticky so silt added to remove the adhesive layer
RAS compared to other methods of farming
more dependent on expert management, greater difficulty in determining when animals are not healthy, much faster time to death in nonfunctional system
how to keep biofloc growing
need desirable C:N. Solution-> add carbon (meals, sugars, etc.)
Site selection for cage culture
needs to be somewhat sheltered and some water movement (need aeration and prevent waste build up of unhealthy conditions). Also out of sight for security
microworms
nemotodes, smaller than Artemia. Usually fed in combination with Artemia
commonalities in RAS failures
no previous experiences, technology was labor intensive, poor engineering technology, culture of sensitive species, enterprise was more of a hobby
Suspended solid waste
not removed by settling basins. Removed via screen or granular media (sand, beads, etc.)
Farmed hitch hikers
often unintentionally produced with aquaculture species. Includes pathogens, parasites, invertebrates, algae
Semelparous spawning
one spawn then death (ex. salmon)
what does a bad egg look like
opaque, whitish, turbid
2 ways to disinfect/sterilize water
ozonation or UV-irradiation
cryopreservation of sperm
potential option when sperm are not readily available. Reduce space use. Good option for males with beneficial traits. Use in hybridization
four female reproductive stages
pre-vitellogenic, early vitellogenic, mid-late vitellogenic, spawning
Issues with biofloc
problems of settling. Solution -> aeration, water movement
polyculture
raising culture animals with different feeding habits. Has a primary and secondary species. Different ecological niches (filter feeder and bottom feeder) or different roles in system (channel catfish and tilapia)
four stages of the reproductive cycle
recrudescence, maturation, ovulation, refractory
Beneficial characteristics conservation aquaculture
relatively easy capture and transport, captive breeding is easier than most vertebrates, high reproductive output, rapid growth and early maturity, public accepts stocking of sport fishes in wild
Nile Perch intentional release
released to boost fishing industry. Resulted in near extinction for 100s of species
Iteroparous spawning
repeated spawning, either within season, annually, or multiple years
different types of zooplankton
rotifers (smallest and alive), Brine shrimp (alive), copepods (alive), formulated diet (not alive and largest)
what is GnRH
secreted by the hypothalamus, GnRH stimulates cells in anterior pituitary to make FSH and LH.
How to prevent overfeeding in cage culture
sensor or camera to monitor feed consumption
Spawning considerations
sexual maturity. Exogenous influences (food availability, temperature and photoperiod) and endogenous influences (hormonal control)
Forces that diminish genetic diversity
small pop size, bottleneck, genetic drift, inbreeding depression, artificial selection in captivity, mixing of genetic stocks
Host fish for mussels
some mussel species are specialized for specific fish species, while some are more generalists
Name three types of freshwater mussels
southern combshell, kidney shell, alabama creek mussel
Reproduction in conservation aquaculture
spawning multiple fish, techniques depend on species. Use different broodstock annually and cryopreservation of male gametes
what are the hatchery phases
spawning, incubation, hatching, yolk-sac absorption, early rearing, fingerlings transferred to grow-out facilities
Sperm in artificial induction
sperm collected in advance. Prevent contact with water until mixing with eggs. Can either be cool-stored or cryopreserved
Broodfish in conservation aquaculture
sufficient #s needed based on # of eggs needed, normal mortality rates, and "quality" of offspring
What is the purpose of hormone injections
synchronize spawning, compress spawning season, induce maturation in fish that won't spawn in captivity, increase milt production
What does a good egg look like
transparent/pigmented, shining, clear
Copepods
type of zooplankton that is an alternative feed used for certain fish species. They contain HUFAs without enrichment and are an important natural food source
Rotifers
type of zooplankton, unstable. Two types, batch or continuous with some species being better adapters to FW or SW
different ways to determine number of fry
volumetric, weight, automated counters
what are the two benefits to a biofloc system
waste control and supplemental food source
What are some things that hav caused mussel decline
water flow alterations, loss of host fish, shoreline erosion, suspended sediments and sedimentation, invasive species, pollution, overharvest
UV-irradiation
water passes UV lights. Efficiency decreases with time (fading bulb, particulate matter deposits) and turbidity
does temperature effect development
yes
what are the fish developmental stages in order
zygote -> blastula -> epiboly -> gastrula -> neurulation
limitations to polyculture
culture capacity may not increase, water quality, handling/sorting harder if species are together
three male reproductive stages
developing, fall/maturing, spawning
Milt
egg and sperm
Do marine fish larvae require HUFAs
Yes since they cannot synthesize.
Do glochidia harm their host fish
Yes, damages fish gills. Too many on one fish can kill fish but fish's immune system only allows them to be "infected" once
long lived species conservation aquaculture
actions need to be carefully thought out. Recovery a slow and expensive process (ex. sturgeons, suckers)
How to remove CO2 from RAS
aeration, surface agitation
Single batch
all fish are the same age and size harvested at the same time
emergency protocols in place for RAS
back up generators, automated water quality monitoring
three types of biofiltration
bead filter, trickle tower, rotating biocontactor
what is the mussel larvae called and what does it look like
called glochidia and looks like a bear trap
What happens after artificial injection
careful monitoring to wait for females to ovulate and eggs leak to bottom of tank. Eggs then collected and females are removed from tank
what chemicals are used for disinfection
chlorine and bleach
Obtaining fish in conservation aquaculture
collection of wild broodstock. Held in captivity
aquaponics
combined culture of fish and plants. Fish waste feeds plants, plants reduce waste discharge. Benefits are quick growth and sell for high price
What are the typical conservation aquaculture species
commercially important species (salmon, sturgeon) and intrinsically/ecologically valuable species (suckers, minnows, catfish, gar)
