Detailed Study Notes on Fisheries and Fishing Gear Types

Types of Fisheries

Traditional Fisheries

• Established long ago by specific communities.

• Development of customary patterns of rules and operations.

• Strongly influenced by religious practices or social customs.

• Knowledge passed down through generations by word of mouth.

• Typically small-scale and/or artisanal.

Subsistence Fisheries

• Catch is shared and consumed by families and kin.

• Pure subsistence fisheries are rare as parts are often sold or exchanged for other goods or services.

Recreational (Sport) Fisheries

• Focus on harvesting fish for personal use, leisure, and challenge.

• Not oriented towards profit or research; sale, barter, or trade is excluded.

Commercial Fisheries

• Aimed at profit with the objective to sell the catch on the market.

• Sales can occur through auction halls or direct contracts.

Scale of Commercial Fisheries

Industrial Fisheries

• Capital-intensive fisheries utilizing large vessels and advanced technology.

• Features:

  • Mechanization, advanced fish-finding and navigation equipment.

  • Long fishing trips, high production capacity, and high catch per unit effort (CPUE).

  • Example: trawl fishery for sandeel in the North Sea or Peruvian purse-seine fishery for anchoveta.

Small-scale Fisheries

• Labor-intensive operations with small crafts.

• Characterized by little capital per person on-board and typically family-owned.

• Low fuel consumption, primarily for subsistence or local commercial markets.

Artisanal Fisheries

• Usually traditional and involve fishing households as opposed to commercial companies.

• Characterized by small amounts of capital and equipment, small vessels, and short fishing trips.

• Primarily local consumption or small-scale export.

• Conflict may arise over resource targeting between artisanal and industrial fisheries.

Scale of Commercial Fisheries Overview

• High Cost: Industrial Fisheries (Large Scale)

• Low Cost: Small Scale Fisheries

Ideal Fishing Gear

• Highly selective for target species and sizes.

• Negligible impact on non-target species, sizes, and habitats.

• Effective, achieving high catch at low cost.

Gear Considerations

Species Targeting

Target and Non-target Species

• Understand the target species to avoid unintentional catch of non-target species (bycatch).

Size of Targeted Fish

• Larger fish generally require bigger hooks.

• Premier Fishing Hook Size Chart indicating appropriate sizes for different targeted fish.

Impact on Habitat

• Evaluate the impact of gear on the environment including weather and currents.

Selectivity in Fishing Gear

Types of Selectivity

1. Knife-edged Selectivity

   • No fish recruit into the fishery until a certain age. All fish above this age remain equally vulnerable.

2. Linear Increase to Full Selectivity

   • Above a certain age, all fish become equally vulnerable, beneficial for mortality estimates from catch curves.

3. Asymptotic Increase to Full Selectivity

   • Reflects gradual recruitment of new cohorts into the fishery; has an upper limit similar to linear increase.

4. Dome-shaped Selectivity

   • Gradual recruitment to a peak followed by a decline in recruitment; can result in under-sampling of larger fish.

Fishing Gear and Selectivity

• Selectivity Shapes and Implications:

• Immediate implementation in management practices can significantly improve conservation outcomes.

• Observed catch age/length and implications for assessment models correlated with selectivity patterns.

Impacts of Fishing Gear

Bycatch Issues

• Common species caught unintentionally include:

  • Sea turtles, marine mammals, and non-target fish.

• Mitigation strategies include use of bycatch reduction devices and appropriate gear modifications.

Habitat and Ecological Considerations

• Bottom trawling can severely impact benthic habitats and alter community structures.

• High bycatch percentages typically associate with mobile enclosing nets.

Aids to Fishing

Fishing Aggregation Devices (FADs)

• Floating objects attracting fish, enhancing catch rates but may result in increased bycatch.

Bubble Curtains

• Bubbles released to herd fish towards capture structures and mitigate noise pollution.

GPS and Depth Sounders

• Technological advances enabling precise returns to profitable fishing spots, increasing efficiency but posing ecological concerns.

Key Takeaways

• Understanding the distinctions between different types of fisheries and fishing gear is vital for effective management and conservation.

• Focus should be maintained on minimizing ecological disturbances and enhancing selectivity to promote sustainable fishing practices.

1. Hooks and Lines

   • Description: Utilizes baited hooks attached to a line, typically for catch-and-release or targeted capture.

   • Pros:

     • Selective for target species.

     • Minimal bycatch if used correctly.

   • Cons:

     • Labor-intensive.

     • Limited to the number of hooks allowed per line.

   • Cost: Less expensive.

2. Nets

   • Types:

     • Gill Nets: Mesh nets that catch fish by their gills.

     • Roundhaul Nets: A type of seine net that encircles fish schools.

   • Pros:

     • Effective for large catches.

     • Versatile for various species.

   • Cons:

     • Can result in high bycatch.

     • May cause habitat damage, especially bottom trawling.

   • Cost: Expensive depending on type and scale.

3. Traps and Pots

   • Description: Enclosed structures that capture fish or crustaceans.

   • Pros:

     • Low bycatch rates.

     • Can attract target species effectively.

   • Cons:

     • May require frequent checking, leading to higher labor costs.

     • Ineffective for species that migrate.

   • Cost: Less expensive to moderate, depending on design.

4. Trawling Gear

   • Types:

     • Bottom Trawlers: Drag nets along the seabed.

     • Pelagic Trawlers: Operate in the water column.

   • Pros:

     • High volume catch capability.

     • Efficient for large-scale commercial fishing.

   • Cons:

     • Causes significant habitat destruction.

     • High bycatch rates, particularly for juvenile fish.

   • Cost: Most expensive due to capital investment.

5. Longlines

   • Description: Lines with multiple baited hooks spaced along their length, deployed in various water depths.

   • Pros:

     • Targeted fishing for specific species and can be adjusted for depth.

   • Cons:

     • Bycatch can be significant, affecting non-target species like seabirds and turtles.

   • Cost: Moderate expense.

6. Spearfishing

   • Description: Fishing with a spear or a spear gun while diving or surfacing.

   • Pros:

     • Highly selective method, targeting specific species.

     • Minimal environmental impact and bycatch.

   • Cons:

     • Limited to skilled individuals.

     • Requires clear visibility and accessibility to target locations.

   • Cost: Less expensive.

7. Electrofishing

   • Description: Uses electric current to stun fish for capture, primarily used in research and monitoring.

   • Pros:

     • Non-lethal method when used properly.

     • Effective for assessing fish populations.

   • Cons:

     • Requires specialized equipment and trained personnel.

     • Regulation restrictions may limit use.

   • Cost: Expensive due to equipment needs.

8. Hand Gathering

   • Description: Collecting fish or shellfish by hand, often in shallow waters.

   • Pros:

     • Low impact and sustainable if done correctly.

     • Selective and minimal bycatch.

   • Cons:

     • Labor-intensive and time-consuming.

     • Limited to accessible areas and species.

   • Cost: Less expensive.

9. Fishing Aggregation Devices (FADs)

   • Description: Man-made floating objects designed to attract fish, enhancing catch rates.

   • Pros:

     • Increases efficiency for targeting pelagic species.

     • Can improve overall catch rates.

   • Cons:

     • May lead to increased bycatch.

     • Can be mismanaged, resulting in overfishing in certain areas.

   • Cost: Moderate to expensive depending on construction and maintenance.