Aquaculture Exam 3
what do fish farmers need to do in order to be successful?
Contend with Diseases, Provide Nutrition, Sell Wholesale: Buy Retail, Contend with Supply and Demand, Acquire Seed
What are 3 hormones used to induce ovulation (egg release) In fish?
GnRH, HCG, and gonadotropin
List the hormones of the hypothalamus-pituitary- gonadal axis And how they are involved in fish reproduction
GnRH: stimulates hypothalamus , FSH:oocyte growth, LH, testosterone: differentiates male/female, estradiol: ovarian follicle maturation
What hatchery practice induces shrimp to spawn?
eyestalk ablation
Explain methods (3) for tagging fish and the advantages and disadvantages of each
finclips advantage: cheap disadvantage: very temporary, passive integrative transponder advantage: non-visual, permanent disadvantage: expensive, external anchor tags advantage: visual identification and cheap disadvantage: temporary
Explain how fish can be conditioned to breed out of season
fish can be conditioned to breed out of season using environmental cues such as mimicking the photoperiods that may occur in summer during the winter this will require different broodstock groups because there isn't an annual reproductive cycle
From most to least desirable, list the methods for collecting broodstock from the wild
fish traps, dip nets, hook and line, otter trawl/draggers, and gill nets
how can the sex of fish be determined?
ovarian biopsy, using sex steroids, and if the fish is gravid (pregnant) or has milt expression (sperm)
What are 3 reagents used to disinfect fish eggs?
ozone, iodine, chlorine
why are some of these crops so hard to find?
they are caught in the wild rather than farmed
What "stimulant" is added to to the water to induce oyster Spawning?
water that has been heated to be warmer than the water the oysters are in
What are 3 conditions that are conducive for fish "happiness" and promoting tank (volitional) spawning?
well fed, proper density and sex ratio, proper environmental conditioning
Explain precautions that must be employed when transporting wild-caught broodstock to the hatchery
you need oxygen tanks and probably several back up tanks, it can also be helpful to use a stress coat, salt/ice, buffers, anastesia, parasite treatments, and fasting
What is vitellogenin? How is it influenced by broodstock nutrition?
Yolk protein in egg-laying animals Phospholipoglycoprotein and carries Ca++. the more broodstock uptake the larger the vitellogenin will be
What environmental factor causes mass spawning to occur?
ambient water temperatures can cause mass spawning to occur
What are 3 Factors that must be considered when deciding how many broodstock are necessary for an aquaculture operation?
are the fish hermaphroditic, what is the probability those fish will spawn, how many gametes are needed to grow these fish, and what is the necessary sex ratio needed to successfully grow them
what are examples of hard to find aquaculture crops?
black sea bass, grouper, nori, flounder, clam worms, razor worms, octopus, and tuna
what is the most important fish on the farm?
broodstock
what is often the most neglected fish on the farm and why?
broodstock because they are also the oldest fish