Management of Harvesting of Marine Species (Cambridge (CIE) IGCSE Environmental Management): Revision Note

Management strategies aim to protect fish populations and ensure marine species are harvested sustainably

• These strategies prevent overfishing, protect breeding adults and reduce bycatch

Successful management requires cooperation between fishers, governments and international organisations

Smaller boats have lower fishing capacity

• This reduces the number of fish taken at once

Limiting net size restricts how much marine life can be captured

• Helps prevent overharvesting of large areas in a single trip

Larger mesh sizes allow juvenile fish to escape

• Gives young fish time to grow and reproduce

• Protects breeding populations

• Helps maintain long-term fish stocks

Pole and line fishing targets individual fish, using individual fishing poles

• This reduces bycatch because unwanted species can be released

A more selective and sustainable method than large trawling nets

• Helps protect non-target species such as dolphins or turtles

Quotas limit how much of each species can be caught

• Prevents fishers from exceeding sustainable levels

Governments use scientific data to set quotas

• This helps species recover when numbers fall too low

Closed seasons stop fishing during breeding periods

• Allows populations to reproduce and grow

• Protects eggs, larvae and young fish

• Increases long-term sustainability

Restricting fishing days reduces the total amount caught

• Helps prevent overfishing throughout the year

• Allows fish populations time to recover between fishing periods

Marine protected areas (MPAs) restrict or ban fishing in certain zones

• These areas act as safe breeding grounds

• Populations inside MPAs can grow larger

• Fish may then move into surrounding areas, increasing catches sustainably

Laws regulate how, when and where fishing can occur

These laws help enforce sustainable practices

Penalties for breaking rules discourage illegal fishing

• Includes fines, boat seizures, or bans on fishing licences

Many marine species migrate across international waters

This means countries must work together to manage shared stocks

Agreements set rules on quotas, protected species and fishing methods

Monitoring ensures countries follow the rules

Satellite tracking, inspections and reporting systems help detect illegal fishing

Marine harvesting management strategies vary in effectiveness, cost and difficulty of enforcement

Smaller boats and nets may reduce short-term catches

• This can cause financial difficulties for small-scale fishers

Hard to enforce (e.g. in areas with many small, unregistered or mobile vessels)

Fishers may oppose restrictions if they feel their livelihoods are threatened

Larger mesh reduces immediate catch numbers

• Some fishers may resist the change due to lower income

Illegal use of small-mesh nets can continue without strong monitoring

Less effective if fish populations are already severely depleted

Much slower and more labour-intensive than net fishing

May not meet high commercial demand for seafood

Requires trained workers and a constant bait supply

Political pressure may lead to quotas being set too high

• This reduces the conservation benefit

Requires strong monitoring to prevent illegal fishing

Can encourage fishers to discard unwanted catch to stay within limits

• This increases waste and harms ecosystems

Causes loss of income during the closed period

Compliance depends on effective enforcement

• Illegal fishing during breeding seasons can undo benefits

Short-term economic impacts may make fishers resist the strategy

Fishers may increase effort on allowed days

• This reduces the strategy’s overall effectiveness

Hard to monitor fishing effort in remote coastal areas

Does not directly protect breeding adults unless paired with closed seasons

Restrict fishing grounds, creating conflict with local communities

Require funding for patrols, monitoring and enforcement

Illegal fishing inside MPAs can continue if enforcement is weak

Benefits may take years to appear, so fishers may lose patience or support

Enforcement can be costly and difficult

Laws may exist but not be properly implemented

Strict regulations may reduce short-term income, leading to resistance

Countries may disagree on quotas, enforcement or shared responsibilities

Some nations may ignore regulations or fish illegally in protected zones

Monitoring migratory species across huge ocean areas is challenging and expensive