Aquatic Resources

Total productivity can be increased by

rearing non-competitive species together.

Captive rearing and release example

Population seeding.

Hydroponic productivity increases because of the nutrients and organic matter supply: ________ is full of nutrients that the plants use.

Fish faeces

Temperature

Dependant on species, warmer ________ increase growth rates, but decrease oxygen; Increases metabolic reaction rates.

Water flow

Fish often swim against the flow of water; This is used to get individuals to swim on the same direction, decreasing collisions and disease spread.

Carnivorous species

________, like salmon, are fed of small oily (like herring) fish which are caught easily.

stock density

Increased ________ increases the spread of parasites and diseases.

Herbivorous fish

________ are more likely to find natural food.

Advantages of aquaculture

High productivity

High food conversion rates (energy ratios)

Herbivorous species feed off naturally growing plant species or crop waste.

Habitat fragmentation results in

Exposure to predators.

Dynamite fishing

Stuns fish using shockwaves

Destroys habitats.

hormone injections

Eggs and milt are collected from mature individuals (sometimes using ________)

Different net mesh sizes

This can allow juvenile fish to escape nets

Acoustic deterrent devices

Produces sound waves that repel aquatic species which communicate using echolocation

Biodegradable fishing equipment

Prevents ghost fishing

Different hook shapes/sizes

Specially designed to only catch target species

Decoys

Deter birds from becoming susceptible to ghost fishing.

Artificial control of abiotic and biotic factors to maximise productivity

High food inputs for carnivorous species

Fish farms

Monoculture

Growth hormones

Small nets

Pesticides

Introducing a fish to a pond and allowing it to feed on wild food

Maintaining habitats

Protection from predators

Natural food

Pest control species

Decreases disease

Location

Does the specie thrive in the local abiotic factors

In some species, it is desirable to have a specific sex

Growth rates

Breed stock

Caviar (Andalucía)

Spread of disease is controlled using

Circulating water tanks (fish naturally swim against the flow)

Pesticides

Biological control (lump suckers)

Predation and competition is controlled by

Netting

Bird scarers

Culling of predators

Temperature

Dependant on species, warmer temperatures increase growth rates, but decrease oxygen

Increases metabolic reaction rates

Dissolved oxygen

Fish with high oxygen requirements need aerated tanks

Food waste and faecal matter need to be removed

Fish with low oxygen requirements can be kept at greater densities

Day length

Reproduction is affected by ____________

Some species stop growing when they become sexually mature

Water flow

Fish often swim against the flow of water

This is used to get individuals to swim on the same direction, decreasing collisions and disease spread

Hydroponic productivity increases because of the nutrients and organic matter supply

Fish faeces is full of nutrients that the plants use

Advantages of aquaculture

High productivity

High food conversion rates (energy ratios)

Herbivorous species feed off naturally growing plant species or crop waste

Disadvantages of aquaculture

Carnivorous species have lower productivity

Carnivorous species are fed off fished species

Some species cannot be raised in captivity

Environmental impacts that need to be reduced include

Food supply impacts

Habitat loss

Pesticide pollution

Development of antibiotic resistant bacteria

Lice control impacts

Wild gene pool impacts

Introduction of non-indigenous species

Organic waste pollution