Introduction to Aquaculture Flashcards
Aquaculture is
The controlled cultivation of domestic aquatic animals and plants.
practice of cultivatingaquatic organisms, including fish, mollusks, crustaceans, aquatic plants, and algae such as seaweed.
Word breakdown: Aqua (water) culture (to grow).
- Operating in marine, brackish, and freshwater environments, aquaculture provides food for people and in
smaller amounts supplies fish for (3)
stocking lakes, bait for fishing, and live specimens for home aquariums.
A term often used synonymously with aquaculture.
- The term “fish farming” is often used synonymously with aquaculture.
What are the 4 most important things that keep fish alive?
water (live in water)
water (eat in water)
water (reproduce in water)
water (fish pathogens live in water)
Traditional Fisheries harvest fish from
harvest wild aquatic organisms
for sale.
Aquaculture take place in three general aquatic environment:
Warmwater aquaculture
Coldwater aquaculture
Mariculture
Warmwater aquaculture is
culturing organisms which thrive in
warm, fresh water such as fish, crayfish, and ornamental fish (animals that spawn at temperatures above 15’C).
Coldwater aquaculture is
culturing species which thrive in cool,
fresh water such as trout and salmon (fish that spawn at temperatures below 15’C).
Mariculture is
culturing all forms of organism which are
accustomed to living in a saltwater or brackish environment.
Species include clams, oysters, seaweed, mussels and shrimp, salmon.
Two broad categories of
aquaculture.
Public sector / restoration aquaculture
&
Private sector aquaculture
Public sector/restoration aquaculture is generally aimed at
replenishing depleted fishery stocks to benefit it.
It tends to be conducted by non-profit organizations, or the state government.
Private sector aquaculture has what main goal?
profit as its main motive.
Individuals or large corporations goal is to sell their product for a profit.
The product may be fish for a local, regional, or national market; seafood for a global market, or ornamental fish for
aquaria.
Define raceways.
a water channel, especially an artificial one of running water in which fish are reared.
Overfishing is a form of
overexploitation where fish stocks are reduced to below acceptable levels.
Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself.
Overfishing occurs when more fish are caught than the population can replace
through natural reproduction.
Define depensation.
In population dynamics, depensation is the effect on a population (such as a fish stock) whereby, due to certain causes, a decrease in the breeding population (mature individuals) leads to reduced production and survival of eggs or offspring.
Many regulatory measures are available for
controlling overfishing. Name some.
These measures include fishing quotas, bag
limits, licensing, closed seasons, size limits and the creation of marine reserves and other marine protected areas.
Aquaculture for Stock Enhancement
Fish farming can enclose the entire breeding cycle of the fish, with fish being bred in captivity.
Some fish prove difficult to breed in captivity and can be caught in the wild as juveniles and brought into captivity to increase their weight.
Marine stock enhancement is
the intentional release of cultured juvenile fish and shellfish to increase the
number of recruits to a recruitment-limited fishery or spawning stock.
When fry develop their scales, they’re then called…
fingerlings.
The main environmental effects of aquaculture can be divided into the following five categories:
- Biological Pollution
- Fish for Fish Feeds
- Organic Pollution and Eutrophication
- Chemical Pollution
- Habitat Modification
Environmental effects of aquaculture,
* Biological Pollution:
Fish that escape from aquaculture facilities may harm wild fish populations through competition and inter-breeding, or by spreading diseases and parasites.
Environmental effects of aquaculture,
* Fish for Fish Feeds:
Some types of aquaculture use large quantities of wild-caught fish as feed ingredients, and thus indirectly affect marine ecosystems thousands of miles from fish farms.
Environmental effects of aquaculture,
* Organic Pollution and Eutrophication:
Some aquaculture systems contribute to nutrient loading through discharges of fish wastes and uneaten feed.
Environmental effects of aquaculture,
* Chemical Pollution:
A variety of approved chemicals are used in aquaculture, including antibiotics and pesticides.
Chemical use in aquaculture is low compared to use in terrestrial agriculture, but antibiotic resistance and harm to
nontarget species are concerns.
Environmental effects of aquaculture,
* Habitat Modification:
Marine aquaculture spreads on thousands marine hectares, or roughly 100 square miles.
Aquaculture structures such as net pens and shellfish rafts create a complex, three-dimensional environment in the water column that attracts and aggregates wild fish, their predators, birds, turtles, and
marine mammals.
Some facilities attract marine predators, and can harm them through accidental entanglement or intentional
harassment techniques.
growth promoters in aquaculture are in fact…
sub-therapeutic levels of antibiotics, which increase animal rate of growth.
Antibiotic residues in farmed salmon, and other seafood, like shellfish, that are wild but
live in the vicinity of the salmon farm.
Increases in antibiotic resistance.
Antibiotics are meant to be administered to farmed fish only when a bacterial disease outbreak is identified!
the two biggest mussel producers
China and the EU are the two biggest mussel producers, followed by Chile and New Zealand.
Most of the EU supply of mussels is produced locally.
Chile and New Zealand are the two main suppliers of mussels to the EU, providing our market with frozen products which are used as raw material by the EU processing industry.
Oysters naturally grow in
estuarine bodies of brackish water.
When farmed, the temperature and salinity of the water are controlled (or at least monitored), so as to induce spawning and fertilization, as well as to speed the rate of maturation – which can take several years.
Largest producer of oysters.
China is by far the largest producer, with 80% of total world production, followed by Korea, Japan, the USA and the EU.
The French market is the largest market for oysters in the EU.
Procambarus clarkii is
a freshwater crayfish species, native to the Southeastern United States, but found also on other continents, where it is often an invasive pest.
It is known variously as the red swamp crawfish, red swamp crayfish, Louisiana crawfish, Louisiana crayfish or mudbug.
P. clarkii has also been introduced elsewhere for cultivation, such as Spain, where its success is attributable to its ability to colonize disturbed habitats that would be unsuitable for the native crayfish Astacus astacus.
Over 60% by weight of all crustaceans caught for consumption are
shrimp and prawns, and nearly 80% is produced in Asia, with China alone producing nearly half the world’s total.
The most expensive product that
is obtained from fish?
The most cheap/dangerous product
that is obtained from fish?
The farming of fish involves raising fish commercially in (4)
open ponds,
raceways (tanks),
recirculating systems or
ocean enclosures (cages).
Worldwide, the most important fish species used in fish farming are, in order, (4)
carp,
salmon,
tilapia, and
catfish.
Describe raceways.
also known as a flow-through system, is an artificial channel used in aquaculture to
culture aquatic organisms.
Raceway systems are among the earliest methods used for inland aquaculture.
The water flow rate in a raceway system needs to be sufficiently high to meet the respiratory (dissolved oxygen) requirements for the species concerned and to flush out metabolic waste,
especially ammonia.
the optimum flow through rate depends on the species, because there are differences
in the rates at which oxygen is consumed and metabolic wastes are produced.
For trout, stocking rates of 30 to 50 kg/m3 are normal at the end of a rearing cycle.
