APES overfishing

what is aquaculture

farming of fish, shellfish, mollusks, crustaceans, or aquatic plants by an individual or corporation with the intent to sell the farmed organisms to consumers for profit.

Where does aquaculture occur

Both marine and freshwater environments, depending on the organisms being farmed.

Who’s worldwide leader in aquaculture production

China is the worldwide leader in aquaculture production for both marine and freshwater environments.

What happens as the human population increases and the middle class expands in developing nations

the demand for quality protein sources is increasing

Since 1990s wild fish harvests have been doing what

largely flat (or decreasing)

What gives income to fisherfolk

aquaculture

why is aquaculture kind of better than open-water fishing

its generally less time-consuming and less dangerous than open water fishing.

Aquaculture vs terrestrial agriculture

In terms of acreage and water consumption, aquaculture is more efficient at producing animal protein than terrestrial agriculture, and requires far less fossil fuel inputs.

How does aquaculture relate to overfishing, feeding people, and fossil fuels

Aquaculture helps mitigate overfishing and provides affordable, high quality protein to humans efficiently and with less fossil fuel inputs.

Why have wild catches of fish been largely flat since the 1990s

depletion of stock from overfishing

Whats aquaculture projected to do in the future regarding seafood consumption.

It’s projected to fill the gap in seafood consumption in the future from 49% of consumption now to 62% by 2030.

Downsides of Aquaculture

waste from organisms: can pollute waterways with excess nitrogen, causing algal blooms and hypoxic conditions. This Eutrophication causes aerobic microorganisms consume algae consume O2 creating hypoxic conditions.

uneaten food pellets: from pens can pollute waterways

farmed organisms may escape: from pens and interbreed or compete with wild organisms→ concern about genetic integrity of wild species and preservation of the wild species

The sheer density of organisms in pens means infectious diseases and parasites spread more easily.

• controlled through use of antibiotics/antiparasitics in stocks

• medication residue can contaminate waterways

• diseases in farmed organisms may spread to wild populations

where is shrimp farming done

southeast Asia

how do shrimp escape in shrimp farming

heavy rains or flooding from storms can allow the farmed shrimp to escape, while also allowing the waste from these farms to wash out into the ocean.

advantages of aquaculture as an environmental solution

• provides high-quality protein to a growing human population

• provides stable income to fisherfolk, with less risk than open-water fishing

• less acreage and less water use in kilo-for-kilo comparison with terrestrial agriculture means aquaculture is a more efficient means of animal protein production.

• fewer fossil fuel inputs needed than terrestrial agriculture

explain 2 ways fecal contamination decreases DO levels in water?

fecal contamination increases aerobic bacteria which eat (decompose) the fecal matter. Aerobic bacteria consume DO of water. The fecal contamination also increases the turbidity of the water (absorbs more solar radiation) warms up and carries less DO.

advantages and disadvantages of aquaculture as an environmental solution

advantages

• provides high-quality protein to a growing human population

• provides stable income to fisherfolk, with less risk than open water fishing

• less acreage and less water use in kilo for kilo comparison with terrestrial agriculture means aquaculture is more efficient means of animal protein production

• fewer fossil fuel inputs needed than terrestrial agriculture

disadvantages

• nitrogenous waste (sewage fecal matter contains nitrogenous waste) can pollute waterways leading to eutrophication

• uneaten feed can pollute airways leading to water quality issues

• escaped farmed organisms can interbreed or compete with wild organisms

• diseases and parasites from densely packed farmed populations can spread to wild populations

• medications to control disease in farmed organisms can pollute waterways

With the world’s human population expected to increase substantially over the next two decades, ensuring the cultivation of adequate protein sources without overexploiting our global natural resources will become critical. Proponents of aquaculture have suggested that the farming of aquatic species, such as fish and shrimp may be a potential sustainable solution to this issue.

a) describe an advantage of aquaculture that helps minimize natural resource use.

b) identify a disadvantage of aquaculture, and describe how that disadvantage might lead to an unintended environmental consequence.

a) Aquaculture offers an alternative by supplying a consistent and sustainable source of fish and other aquatic organisms without depleting natural populations. This allows wild species the opportunity to reproduce and maintain their numbers, supporting the overall health and balance of aquatic ecosystems. By shifting a portion of seafood production from open waters to controlled environments, aquaculture plays a vital role in promoting sustainable resource use while meeting the growing global demand for protein.

b) A disadvantage of aquaculture is that it can lead to water pollution due to the accumulation of excess feed, fish waste, and chemicals (like antibiotics) used to prevent disease. This nutrient runoff can cause eutrophication which is a process where water bodies become overly enriched with nutrients, leading to excessive algal blooms. These blooms deplete oxygen levels in the water, creating "dead zones" that can harm or kill aquatic life, ultimately disrupting surrounding ecosystems.

What does overfishing do to people

It has led to the extreme scarcity of some fish species which can lessen biodiversity in some aquatic systems and harm people who depend on fishing for food and commerce.

commercial fishing types

long-line, drift net/gill net, purse seine, trawling, sonar

long-line fishing description

• used by industrial fishing industry

• lines can be up to 20 miles long off the back

• better than trawling or large nets because it gets less bycatch (non target species)

drift net/gill net

not pulled great distances, unfortunately gets lots of bycatch thrown back in the ocean, really big drifitng nets off the boat

purse seine

used with sonar, once school of fish is identified using sonar/satallitle imaging the fishing ship drops nets and when its pulled up it looks like a purse. SInches at the bottom so they cant get out. Lots of bycatch thrown bacl into the ocean.

trawling

• worst offender of bycatch

• net dragged a long ocean floor for great distances also disrupts ecosystem of ocean floor some activities call it an eraser

tragedy of the common in fishermen in 1990s

fishermen werent leaving enough juviniles to repopulate each year

how to make fishing more sustainable

• catch limits based on MSY( maximum sustainable yield)

• limit age/size of fish caught

• modify techniques to reduce bycatch

• laws/treaties that protect critical species

bycatch def

unwanted fish caught during commerical fishing and often die even if thrown back

modified fishing techniques to reduce bycatch and make fishing more sustainable

• Turtle Excluder Devices (TEDs): Special grid systems fitted into trawl nets allow smaller fish to pass through while larger species like turtles escape safely.

• Bycatch Reduction Devices (BRDs): These attachments help non-target species escape from fishing gear by providing exit routes or using mesh sizes that allow juveniles to escape.

• Circle Hooks: Unlike traditional J-hooks, circle hooks are less likely to be swallowed by non-target species, reducing injury and increasing survival rates upon release.

• Selective Fishing Gear: Using gear like pole-and-line, handlines, or traps focuses on specific species and minimizes unintended catches.

• Time and Area Closures: Temporarily or permanently closing fishing areas during spawning seasons protects breeding populations and reduces bycatch.

• Acoustic Deterrents (Pingers): Devices that emit sounds to scare away dolphins, porpoises, and whales from nets, keeping marine mammals safe.

• Real-Time Data and Electronic Monitoring: Fishermen use GPS and digital tracking systems to avoid bycatch hotspots, making their practices more adaptive.

• Modifying Trawls: Adjusting trawl net configurations — like raising the net off the seabed — reduces the catch of bottom-dwelling species.

• Lighted Nets: Studies show that adding LED lights to gillnets helps fish and other marine animals detect and avoid nets, lowering bycatch rates.

• Quota Management and Catch Shares: Implementing science-based quotas prevents overfishing, encouraging fishers to be more selective and cautious.

laws and treaties

the great white shark is protected by SITES (the convention on international trade in endangered species of wild flora and fauna

sustainable fishing includes

• catch limits

• bycatch guards

• treaties and laws

• consumer pressure

• incentives and fines

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