Pair trawling

Dicentrarchus labrax

Pair trawling is a fishing method where two boats tow a single trawl net. This technique is used to capture pelagic fish—species that inhabit the water column, not near the bottom or the shore. Pair trawling is distinct from single-boat trawling, offering several advantages, including the ability to tow larger nets and cover more area, potentially leading to higher catch rates. However, it also raises environmental and sustainability concerns.

Overview

In pair trawling, two vessels sail parallel to each other at a set distance apart, towing a net between them. The net is kept open horizontally by the distance between the boats and vertically by floaters and weights. This method is particularly effective for targeting schooling fish such as herring, mackerel, and tuna. The technique allows for the capture of fish in the mid-water column, avoiding some of the bottom habitat damage associated with bottom trawling.

Environmental Impact

While pair trawling can be efficient, it has been criticized for its potential environmental impacts. Concerns include:

• Bycatch: The capture of non-target species, including juvenile fish and protected species like dolphins and sea turtles.
• Habitat damage: Although less than bottom trawling, pair trawling can still affect the water column and surface habitats.
• Overfishing: The efficiency of pair trawling raises concerns about overfishing and the depletion of fish stocks.

Regulation and Management

Due to these environmental concerns, pair trawling is subject to regulation in many jurisdictions. Measures may include:

• Limiting the size and design of nets.
• Restricting pair trawling in certain areas or during specific seasons to protect vulnerable species or habitats.
• Implementing bycatch reduction devices and strategies.
• Requiring licenses and monitoring pair trawling activities.

Advantages and Disadvantages

Advantages:

• Increased efficiency and catch rate compared to single-boat trawling.
• Ability to target specific pelagic species effectively.

Disadvantages:

• Higher operational costs due to the need for two boats and crews.
• Increased risk of bycatch and potential for overfishing.
• Regulatory restrictions and potential for closures of fishing areas.

Conclusion

Pair trawling is a complex fishing method with both benefits and drawbacks. While it offers an efficient way to capture pelagic fish, it also poses significant environmental challenges. The future of pair trawling will likely depend on the development of more sustainable practices and effective management and regulation to mitigate its impacts on marine ecosystems.