Topic 12: Methods Of Reducing The Environmental Impacts Of Fishing Flashcards
4 ways the environmental impacts can be reduced
Catch quotas
Fishing equipment design and use
Restricting fishing Effort
Restricting fishing methods
What is the purpose of a catch quota?
To set a limit of the total weight of fish that can be landed
It might be divided up between all fishing boats in a fleet
When do catch quotas work best?
When fish are found in single-species shoals
Fishing will stop if the quota for that species is reached
When do catch Quito’s not work/are less effective?
In mixed fisheries when different fish are caught in the same net
If the catch quota for one species has been reached, surplus may be returned to the ocean whilst fishing for the other species continues
The surplus are likely o be returned dead or injured
Give 9 ways fishing equipment designs and uses can be changed to reduce the environmental impacts of fishing
Mesh size
Mesh design
Escape panels acoustic deterrent devices
Hook shape
Decoys
Sinkers
Night fishing
Biodegradable/radiotracked equipment
How can mesh size be altered to reduce the environmental impacts of fishing?
They can be set so that fish below a certain size can escape
How can hook shape be altered to reduce the environmental impacts of fishing?
Longline hooks have curved points
Still catch tuna but less likely to catch albatrosses
Escape panels
Turtle exclusion devices
Large spring loaded escape panels in the nets that allow turtles to escape
Acoustic deterrent devices
Also known as ‘dolphin pingers’
Produce high frequency sounds that warn dolphins about the presents of the net
Decoys
They attract and distract birds so they dont get caught on longline hooks
Sinkers
Weights attached to pelagic longlines
They hold hooks down in the water so they still catch fish but not albatrosses
Night fishing
Using longlines at night when birds aren’t feeding
Biodegradable and radio tracked equipment
Reduces ghost fishing
Traps for crabs and lobsters, if they are held together by biodegradable rope, will fall apart if lost so wont continue to catch organisms
In the USA traps have radio-transmitters that activate if the traps are lost so they can be recovered
How might the fishing effort be restricted in order to reduce the environmental impacts of fishing?
In some areas of the UK there are limits of the size and power of fishing boats, and no of days they can spend fishing
Where the number of fishing boats is so large that overfishing is unavoidable, boat owners may receive compensation for their boats to be decommissioned
9 ways fishing methods are/can be restricted
Ban drifts nets
Bans on demersal trawling
No take zones
Turtle bycatch
Closed-seasons
Minimum and maximum catchable size
Protected individuals
Captive rearing and release
Where might demersal trawling be banned?
In an area where the seabed ecosystem is particularly sensetive or important
E.g. it is banned of the NW coast of Scotland where there are deep water coral reefs
No take zones
Areas where fishing and other activities that exploit wildlife or damage habitats are not permitted
Protects breeding populations and allows them to colonise other areas where populations have bed reduced by fishing
The communities of species that live within the zone can recover because damaging activities are stopped
How can turtle bycatch be reduced?
By reducing the time the net is towed especially in tropical fishing areas
Less time caught in the net means less chance of drowning
Closed seasons
Ban on fishing for part of the year
Allows fish to grow
Is ideal for breeding seasons to help sustain future generations
Minimum catchable size
Banning the capture of small fish
Allow they to grow larger and live lng enough to breed
Maximum catchable size
Protecting large individuals to make sure there is a surviving population of breeding adults
Captive rearing and release, or ‘population seeding’
Wild populations of some species may be increased by releasing individuals raised in captivity
Most species spend their first few weeks drifting in plankton before settling on seabed and colonising habitats- releasing captive raised species increased chances of survival in this period
