Purse Seine

Indian Ocean

Purse seines are large nets used to encircle and trap large schools of fish. In addition to the target fish, these nets also trap all other encircled animals including ETP species. Purse seines can reach over 200 m deep and be over 2,000 m long.

Target Species

Tuna

Bycatch Species

Marine Mammals

Seabirds

Sharks and Rays

Solutions

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Gears and Best Practices

Non-Entangling Biodegradable FAD

Fish aggregation devices (FADs) are structures that attract target fish, normally tuna, which the are used to increase fishing efficiency. Nets and ropes that attach to the main structure and hang in the water often entangle non-target species such as sea turtles, seabirds, and sharks that are also attracted to the FAD.

Fishery Type

Purse Seine

Ocean Region

Indian Ocean, Eastern Pacific Ocean, Western Pacific Ocean, Northern Atlantic Ocean

Target Species

Tuna

Bycatch Species

Marine Mammals, Sea Turtles, Sharks and Rays

Gears and Best Practices

Non-Dolphin/Whale Shark Sets

Dolphins/porpoises and whale sharks are often found with target fish in the open ocean, and were often used as an indication of where to set purse seine nets. This led to large bycatch rates for both in historical purse seine fisheries leading to very high mortality rates.

Fishery Type

Purse Seine

Ocean Region

Indian Ocean, Eastern Pacific Ocean, Western Pacific Ocean, Northern Atlantic Ocean

Target Species

Tuna

Bycatch Species

Marine Mammals, Sharks and Rays

Gears and Best Practices

Backdown Method

The backdown method is conducted after setting the purse seine net but before finishing the haul. This process creates a channel and an opening at the back of the net where non-target species (especially small cetaceans and sea turtles) can escape at the surface.

Fishery Type

Purse Seine

Ocean Region

Indian Ocean, Eastern Pacific Ocean, Western Pacific Ocean, Northern Atlantic Ocean

Target Species

Salmon, Tuna

Bycatch Species

Marine Mammals, Sea Turtles, Sharks and Rays

The Problem

The modern fishery deploys fish aggregating devices to increase fishing efficiency, though they also aggregate ETP species that can become entangled directly in the FAD or caught in the net. With proper handling, most ETP bycatch can be released alive.