Discover the various fishing techniques, including methods of capture fisheries such as trawling, longlining, and gillnetting. Learn about sustainable fishing practices that help protect marine resources and ensure long-term fish production.
Fishing Techniques: Methods of Capture Fisheries and Sustainable Practices
Introduction
Fishing is an essential activity for food production, employment, and economic growth worldwide. However, overfishing and destructive fishing methods have raised concerns about the sustainability of marine and freshwater resources. To balance fish harvesting with conservation, capture fisheries—which involve catching fish from natural water bodies—must employ efficient and sustainable techniques.
This blog explores different methods of capture fisheries and highlights sustainable fishing practices that help maintain aquatic ecosystems.
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Methods of Capture Fisheries
Capture fisheries involve harvesting fish from oceans, seas, rivers, lakes, and other natural water bodies. The techniques used depend on the type of water body, fish species, and purpose of fishing. The main methods include:
Methods of Fishing Techniques
1. Trawling
Description:
- A fishing method that involves pulling a large net (trawl net) through the water or along the seabed.
- Used in deep-sea and commercial fishing.
- Two main types:
- Bottom trawling – Drags a net along the seabed to catch bottom-dwelling fish (e.g., cod, shrimp).
- Midwater trawling – Targets fish swimming in open waters (e.g., herring, mackerel).
Advantages:
- High fish-catching efficiency.
- Suitable for large-scale commercial fishing.
Disadvantages:
- Destructive to marine habitats, especially bottom trawling, which damages coral reefs.
- Results in bycatch (accidental capture of non-target species).
2. Longlining
Description:
- A fishing technique that uses a main fishing line with multiple baited hooks.
- Can be pelagic (open ocean) or demersal (near the seabed).
- Targets species like tuna, swordfish, and halibut.
Advantages of this fishing techniques:
- Selective, reducing unnecessary bycatch.
- Effective for catching large fish.
Disadvantages of this fishing techniques
- Can still harm non-target species, such as sea turtles and seabirds.
- Labor-intensive and time-consuming.
3. Gillnetting
Description:
- A curtain-like net that traps fish by their gills as they try to swim through.
- Can be used in shallow coastal areas, rivers, and deep waters.
Advantages:
- Effective for catching specific fish sizes.
- Less destructive to the seabed compared to trawling.
Disadvantages:
- Can lead to high bycatch rates, trapping unintended species like dolphins and sea turtles.
- Some forms, like drift gillnets, are banned in certain areas due to environmental concerns.
4. Purse Seining
Description:
- A large net with floats is used to encircle a school of fish.
- The bottom of the net is then pulled together, trapping the fish inside.
- Commonly used to catch sardines, anchovies, and tuna.
Advantages:
- Highly efficient in capturing schooling fish.
- Less impact on the seabed.
Disadvantages:
- Can cause overfishing if not properly regulated.
- Bycatch is a concern, particularly for species like dolphins.
5. Trap Fishing (Fish Traps and Pots)
Description:
- Involves placing baited cages or traps in water to catch fish or crustaceans (e.g., crabs, lobsters).
- Traps allow fish to enter but make it difficult for them to escape.
Advantages:
- Minimal environmental impact.
- Can be species-selective, reducing bycatch.
Disadvantages:
- Requires frequent monitoring to prevent loss of trapped fish.
- Can be expensive to maintain.
6. Spearfishing
Description:
- A traditional fishing method using a spear, harpoon, or spear gun to catch fish.
- Done manually by divers in shallow waters.
Advantages:
- Highly selective, with no bycatch.
- No impact on marine habitats.
Disadvantages:
- Limited to small-scale fishing.
- Requires skill and experience.
7. Handlining and Jigging
Description:
- Handlining: A simple method using a single fishing line with a baited hook.
- Jigging: Uses a jerking motion to attract fish with an artificial lure.
Advantages:
- Eco-friendly, as it produces minimal waste.
- Good for small-scale or subsistence fishing.
Disadvantages:
- Not effective for large-scale fishing.
- Labor-intensive.
8. Drift Net Fishing
Description:
- Involves setting up floating nets that drift with ocean currents, catching fish as they swim into them.
- Used to catch species like tuna, salmon, and squid.
Advantages of this fishing techniques:
- Can catch large quantities of fish.
- Less labor-intensive than active fishing methods.
Disadvantages of this fishing techniques:
- High bycatch rates, often trapping dolphins, turtles, and seabirds.
- Ghost fishing—lost nets continue trapping marine life, causing ecological harm.
- Many countries have banned large-scale drift net fishing due to environmental concerns.
9. Harpooning
Description:
- A traditional fishing method where fishers use a harpoon (spear-like weapon) to directly target large fish, such as whales, tuna, and swordfish.
- Often used in artisanal and subsistence fishing.
Advantages:
- Highly selective, reducing bycatch.
- No impact on marine habitats.
Disadvantages:
- Requires great skill and is not suitable for large-scale fishing.
- Less efficient compared to modern fishing methods.
10. Cast Net Fishing
Description:
- Fishermen throw a circular net with weights around the edges into the water.
- The net sinks and traps fish before being pulled back in.
- Common in shallow coastal waters, rivers, and lakes.
Advantages:
- Simple and cost-effective for small-scale fishing.
- Eco-friendly, as it has minimal impact on aquatic habitats.
Disadvantages:
- Limited catch size, making it impractical for large-scale commercial fishing.
- Requires manual labor and skill.
11. Weir Fishing (Fish Weirs)
Description:
- Uses barriers or fences built in water to direct fish into a trap.
- Common in shallow rivers, estuaries, and coastal areas.
Advantages of this fishing techniques:
- Low environmental impact and selective fishing.
- Can be used seasonally to allow fish stocks to recover.
Disadvantages of this fishing techniques:
- Not effective for large-scale commercial fishing.
- Can block fish migration if not properly designed.
12. Electro Fishing
Description:
- Uses electric currents in water to temporarily stun fish, making them easier to collect.
- Often used in scientific research and fish population control rather than commercial fishing.
Advantages:
- Non-lethal, as stunned fish can recover.
- Helps in population studies and fish relocation.
Disadvantages:
- Can be harmful if not properly regulated.
- Not suitable for deep-sea fishing.
13. Bottom Longlining
Description:
- A specialized form of longlining where baited hooks are set along the seabed to catch bottom-dwelling species like halibut, cod, and groupers.
Advantages:
- Highly targeted, reducing unwanted bycatch.
- Efficient for deep-sea commercial fishing.
Disadvantages:
- Can still harm seabed habitats and corals.
- Risk of gear loss, which can lead to ghost fishing.
14. Hand Gathering
Description:
- Involves manually collecting shellfish, crabs, or fish from shallow waters, rocks, or beaches.
- Common in subsistence and traditional fishing communities.
Advantages:
- Eco-friendly with no habitat destruction.
- Zero bycatch, as fishers choose what they collect.
Disadvantages:
- Labor-intensive and time-consuming.
- Limited to shallow coastal areas.
15. Dynamite (Blast) Fishing [Illegal]
Description:
- Uses explosives to kill or stun fish, making them float to the surface for collection.
Disadvantages:
- Highly destructive, killing marine life indiscriminately.
- Destroys coral reefs and marine habitats.
- Illegal in most countries due to environmental damage.
16. Poison (Chemical) Fishing [Illegal]
Description:
- Uses chemicals (e.g., cyanide) to stun or kill fish, making them easier to catch.
Disadvantages:
- Toxic to marine life, harming entire ecosystems.
- Health hazards for fishers and consumers.
- Banned worldwide due to its destructive impact.
Sustainable Fishing Practices
To ensure the long-term availability of fish stocks, sustainable fishing techniques must be adopted. These include:
1. Selective Fishing Gear
- Using gear that targets specific fish sizes to avoid catching juvenile fish.
- Examples include circle hooks (to reduce bycatch) and modified nets with escape gaps for non-target species.
2. Seasonal and Area Closures
- Fishing bans during breeding seasons allow fish populations to replenish.
- Marine protected areas (MPAs) help conserve habitats and fish stocks.
3. Catch Limits and Quotas
- Governments set limits on how many fish can be caught to prevent overfishing.
- Individual fishing quotas help regulate commercial fishing activities.
4. Eco-Friendly Aquaculture
- Farming fish in controlled environments reduces pressure on wild fish populations.
- Sustainable fish farming includes using plant-based feed and avoiding pollution.
5. Bycatch Reduction Techniques
- Turtle Excluder Devices (TEDs) allow turtles to escape from fishing nets.
- Dolphin-safe nets prevent accidental capture of marine mammals.
6. Community-Based Fisheries Management
- Encourages local communities to take responsibility for protecting their fishing resources.
- Traditional knowledge and modern regulations are combined for better resource management.
Revision Questions and Answers on Fishing Techniques
1. What are capture fisheries?
- Capture fisheries involve harvesting fish from natural water bodies like oceans, lakes, and rivers without artificial breeding.
2. Name three common fishing techniques used in capture fisheries.
- Trawling, longlining, and gillnetting are common fishing methods.
3. What is the main disadvantage of bottom trawling?
- It destroys marine habitats and leads to high bycatch.
4. How does purse seining work?
- It uses a large net to encircle a school of fish, then closes at the bottom to trap them.
5. Mention two sustainable fishing practices.
- Catch limits and seasonal closures help prevent overfishing.
6. Why is community-based fisheries management important?
- It allows local communities to protect and manage their fishing resources, ensuring sustainability.
Conclusion On Fishing Techniques
Capture fisheries use various methods, ranging from traditional techniques like spearfishing and trap fishing to large-scale commercial methods like trawling and longlining. While some methods, like harpooning and cast net fishing, are sustainable, others—like drift nets and bottom trawling—pose environmental threats.
To preserve fish populations, it is essential to adopt sustainable fishing practices such as selective gear, fishing quotas, seasonal closures, and marine protected areas. By balancing fish harvesting with conservation, we can ensure that fisheries continue to provide food and livelihoods for future generations.