TEST 3 Flashcards
Prawn feeding type
ominvours
Male morphotypes (prawns)
smale male then organe claw, then blue claw
density of males (prawns)
younger males do not mature if there is a large organe claw or even larger blue claw
male sperm (prawns)
gelatinous mass that is held underneath the body of the female
After fertalization gravid females migrate…(prawns)
downstream to tjhe estuary where th eggs hatch as free-swimming larvae
How many molts do the newly hatched larvae go through (prawns)
11 molts in 35 days
Mating (prawns)
11 well-pigmented male to several female
fresh tank water
female molt becomes soft
eggs (prawns)
Fertalized eggs change from orange to greyish brown when they are ready to hatch
Culture (prawns)
females with eggs moved to salt water after hatching
First stage zoea are …..long (prawns)
2 mm
Eyestalk ablation
is effective in forcing females to produce eggs. However, not needed with prawns since they readily reproduce
Larval rearing
may start at high levels, reduce dilution in the same tank, feed 4-6 ties a day
Post-larvae
will cannibalism, armetia is no longer required
Nile tilapia (Oreochromis niloticus):
Can grow very large (largest example was 2 ft in length).
Temperature range from 56-91 °F, but 80-90 is best.
Reaches sexual maturity in 5-6 months- ¾-1 pound.
A mouthbrooding species (both eggs and fry).
Least saline tolerant- up to 15 ppt
Has dark-colored flesh (market resistance).
Blue tilapia (Oreochromis aureus)
Is more cold tolerant than other tilapia with a low-end value in the 40’s rather than the 50’s
Largest known example was about 1.5 ft in length.
Reach sexual maturity at about 4 inches.
A mouthbrooding species (both eggs and fry).
Saline tolerant up to 20 ppt
Mozambique Tilapia (Oreochromis mossambicus)
Largest has been about 16 inches in length
Perhaps more adaptable with its diet- including fry.
Very saline tolerant- up to 35 ppt.
A mouthbrooding species (both eggs and fry).
Sexual maturity earlier than Blue and Nile species, ~ 2-3 months
Wami Tilapia (Oreochromis urolepis)
Largest has been about 9.5 inches in length.
Does not grow as fast as others
Reproduction (Tilapia)
Male makes a ‘nest’ (depression in ground), the female arrives and deposits eggs, male fertilizes, female collects eggs in mouth to incubate, female leaves and a new female arrives to the male’s nest to get her eggs fertilized.
7 days until swimming out of mouth, 10 days until she won’t let them back in.
Tilapia (Genetics)
44 chromosome pairs, 21 autosomes
ZW system-
ZW Female
ZZ male
XY system -
XX (female)
XY (Male)
XY System (TYPES)
The Nile tilapia (Oreochromis niloticus)
The Mozambique Tilapia (Oreochromis mossambicus)
ZW System (TYPES)
The Blue tilapia (Oreochromis aureus)
The Wami Tilapia (Oreochromis Urolepis)
Hybridization
Commercially grown tilapia are almost always a hybrid between any of the four species mentioned previously, either with each other, or with hybrids.
Viable tilapia culture requires all Males (or at least >95% male).
Male tilapia grow faster
If females present:
energy lost to breeding
results in small fish (especially females)
Ponds become overcrowded with offspring of small and varying sizes.
Hapas (grow-out)
Used mostly for Breeding and nursery
Columnaris
Caused by a bacterium named Flavobacterium columnare
Streptococcosis
Caused by a bacterium named Streptococcus agalactiae, and less lethal S. iniae.
Associated with larger fish and stress, but can also occur in apparently healthy fish.
Crassostrea virginica (Eastern oyster)
Found on East Coast and the Gulf of Mexico.
Crassostrea gigas (Pacific oyster)
Found on pacific coast.
Some have a ‘fluted’/ruffled shell
Grows larger than C. virginica.
Tastes different than C. virginica (so they say!)
Adult Oysters
Pump large volumes of water (several gallons/hour).
Consume microalgae and zooplankton.
Produce pseudofeces.
Top/left and bottom/right shell.
Shell has straight and curved sides.
Pump from curved to straight.
Larval Growth
Stages
fertilized egg,
trochophore,
swimming straight-hinge (‘D’) veliger,
swimming late veliger,
Crawling ‘eyed’ pediveliger
has byssal thread for initial attachment
Spat (settled larvae)
Feeding:
Velum-mouth-stomach-intestine-anus
Larvae production
Reproduce by ‘broadcast spawning’.
Hatchery method: Spawning
Stress.
Induced with gametes.
Don’t kill oyster.
Not always successful.
Uncontrolled mixing of gametes.
Hatchery method: Stripping
Kill oyster.
Control mixing of gametes.
High success rate.
Cultchless seed:
‘Cultchless’ oysters are young oysters that do not, or appear not, to adhere to substrate. They can be produced by:
Eyed larvae
: for your remote setting operations. On average set rate of our eyed larvae is around 18% but typical results range form 10-25%.
Oyster seed
1mm and 2mm grade.
Nursery
Up/Down-weller
Down-weller used in hatchery to set eyed larvae on micro-cultch.
Up-weller used in nursery to grow spat to size suitable for grow-out.
Principle:
To pass water past cultch or spat
Up-weller
Water added to tank by pipe in back of tank
flows past screen and spat at bottom of each silo
exits through pipe at top of each silo
Exits into center troth and drained out of system
Down-weller
Container with screen on bottom
Micro-cultch placed on top of screen.
Eyed-larvae placed in container to set on cultch.
Water added at top of container flows past cultch and drained out with out loosing larvae.
Grow-out (OYSTERS)
Differs with location
Bottom (free or caged)
Suspension
Hybrid
Differs with location
Pseudofeces
not true feces that has passed through the oyster’s gut, but solid waste that the oyster filters from the water and wraps up as a thin solid ribbon.
Trochophore
free swimming larval stage of the oyster- you should be able to recognize what it looks like. This stage comes before the oyster looks like a small letter D
Veliger
Larger larval stage with two shells that resembles and adult oyster, but no longer D shaped. You should be able to recognize what it looks like.
Pediveliger
Largest free swimming larval stage of the oyster larva that develops a foot that it can crawl around with. In the latest stage, the animal develops a small photosensitive area called the eye spot that helps it stay in dark areas. You should be able to recognize what it looks like.
Spat
newly settled oyster larvae that have glued themselves to a substrate.
Umbo
The top part of the larval oyster that corresponds to the hinge and is opposite to the side that opens up to allow it to swim.
Setting
process of selecting a permanent spot to glue to. The process involves first throwing out ‘thread’ that resembles a fine spider’s web. This catches on surfaces that the oyster is swimming by. The oyster then pulls itself onto the surface and starts to crawl around till it finds a place away from light that it likes for gluing itself permanently to.
Cultch
the material that an oyster glues itself to
Stripping
Artificial insemination
Recirculating systems
raise large quantities of fish in relatively small volumes of water by treating the water to remove toxic waste products and then reusing it
Raft hydroponics
uses floating polystyrene sheets and net pots for plant support, can provide sufficient bio-filtration if the plant production area is large enough
Nutrient thin flim (NFT)
uses a thin layer of water to bathe roots, but as roots grow thicker, air may not be able to get to the roots
Suspended solids
solids may stick to plant roots and create small areas that are anaerobic preventing nutrient uptake which needs oxygen.
Want Oxygen
to 80% saturation (6-7mg/L oxygen, atmospheric O2 is 21%)
Decomposition promotes
release of inorganic nutrients into the water (mineralization) that plants can use. Decomposition microbes compete with pathogens and keep the system healthier.
seven micronutrients
Include chlorine (Cl), iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu) and molybdenum (Mo).
Biofilter needs
high surface area for nitrifying bacteria (Nitrosomas and Nitrobacter) film
NFT-nutrient film technique
Aquaponics culture system in which plant roots are bathed in solution that brings nutrients to the plant.
Raft culture
Type of floating culture in which plants are floated on the surface of a container. The floating material is usually sheets of polystyrene or other floating material. Using these sheets keeps the plants suspended at the surface and also reduces evaporation water loss.
DO- dissolved oxyge
Oxygen that is dissolved in water. Saturated dissolved oxygen is about 9 ppm.
BOD
biological oxygen demand- the amount of oxygen that all of the organisms living in a body of water needs to stay alive.
Mineralization
the process of release of the minerals that are in feed or other materials as they decompose.
Flood and drain system
type of aquaponic system that is set up so that an automatic siphon (similar to how a toilet works) is set up that will drain the system when the water gets to a certain height. The system is then allowed to refill again till it drains in an new cycle when the water get to that predetermined height.
