Introduction to Aquaculture

Question 1

Aquaculture is

Answer 1

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).

Question 2

• Operating in marine, brackish, and freshwater environments, aquaculture provides food for people and in
  smaller amounts supplies fish for (3)

Answer 2

stocking lakes, bait for fishing, and live specimens for home aquariums.

Question 3

A term often used synonymously with aquaculture.

Answer 3

• The term “fish farming” is often used synonymously with aquaculture.

Question 4

What are the 4 most important things that keep fish alive?

Answer 4

water (live in water)
water (eat in water)
water (reproduce in water)
water (fish pathogens live in water)

Question 5

Traditional Fisheries harvest fish from

Answer 5

harvest wild aquatic organisms
for sale.

Question 6

Aquaculture take place in three general aquatic environment:

Answer 6

Warmwater aquaculture
Coldwater aquaculture
Mariculture

Question 7

Warmwater aquaculture is

Answer 7

culturing organisms which thrive in
warm, fresh water such as fish, crayfish, and ornamental fish (animals that spawn at temperatures above 15’C).

Question 8

Coldwater aquaculture is

Answer 8

culturing species which thrive in cool,
fresh water such as trout and salmon (fish that spawn at temperatures below 15’C).

Question 9

Mariculture is

Answer 9

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.

Question 10

Two broad categories of
aquaculture.

Answer 10

Public sector / restoration aquaculture
&
Private sector aquaculture

Question 11

Public sector/restoration aquaculture is generally aimed at

Answer 11

replenishing depleted fishery stocks to benefit it.

It tends to be conducted by non-profit organizations, or the state government.

Question 12

Private sector aquaculture has what main goal?

Answer 12

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.

Question 13

Define raceways.

Answer 13

a water channel, especially an artificial one of running water in which fish are reared.

Question 14

Overfishing is a form of

Answer 14

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.

Question 15

Define depensation.

Answer 15

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.

Question 16

Many regulatory measures are available for
controlling overfishing. Name some.

Answer 16

These measures include fishing quotas, bag
limits, licensing, closed seasons, size limits and the creation of marine reserves and other marine protected areas.

Question 17

Aquaculture for Stock Enhancement

Answer 17

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.

Question 18

Marine stock enhancement is

Answer 18

the intentional release of cultured juvenile fish and shellfish to increase the
number of recruits to a recruitment-limited fishery or spawning stock.

Question 19

When fry develop their scales, they’re then called…

Answer 19

fingerlings.

Question 20

The main environmental effects of aquaculture can be divided into the following five categories:

Answer 20

• Biological Pollution
• Fish for Fish Feeds
• Organic Pollution and Eutrophication
• Chemical Pollution
• Habitat Modification

Question 21

Environmental effects of aquaculture,
* Biological Pollution:

Answer 21

Fish that escape from aquaculture facilities may harm wild fish populations through competition and inter-breeding, or by spreading diseases and parasites.

Question 22

Environmental effects of aquaculture,
* Fish for Fish Feeds:

Answer 22

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.

Question 23

Environmental effects of aquaculture,
* Organic Pollution and Eutrophication:

Answer 23

Some aquaculture systems contribute to nutrient loading through discharges of fish wastes and uneaten feed.

Question 24

Environmental effects of aquaculture,
* Chemical Pollution:

Answer 24

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.

Question 25

Environmental effects of aquaculture, * Habitat Modification:

Answer 25

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.

Question 26

growth promoters in aquaculture are in fact...

Answer 26

sub-therapeutic levels of antibiotics, which increase animal rate of growth.

Question 27

Antibiotic residues in farmed salmon, and other seafood, like shellfish, that are wild but

Answer 27

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!

Question 28

the two biggest mussel producers

Answer 28

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.

Question 29

Oysters naturally grow in

Answer 29

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.

Question 30

Largest producer of oysters.

Answer 30

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.

Question 31

Procambarus clarkii is

Answer 31

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.

Question 32

Over 60% by weight of all crustaceans caught for consumption are

Answer 32

shrimp and prawns, and nearly 80% is produced in Asia, with China alone producing nearly half the world's total.

Question 33

The most expensive product that is obtained from fish?

Question 34

The most cheap/dangerous product that is obtained from fish?

Question 35

The farming of fish involves raising fish commercially in (4)

Answer 35

open ponds, raceways (tanks), recirculating systems or ocean enclosures (cages).

Question 36

Worldwide, the most important fish species used in fish farming are, in order, (4)

Answer 36

carp, salmon, tilapia, and catfish.

Question 37

Describe raceways.

Answer 37

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.