Fish attractors to increase catches by small-scale fishermen

Subsistence, non-commercial fishing (also known as artisanal fisheries) accounts for almost 50 per cent of Brazil’s fish catch.

Research is helping increase catches of an assortment of fish, including small tuna, carangid, dolphin fish, and shark, by small scale fisheries along Brazil’s northeastern coast. The focus is on better knowledge about the distribution and abundance offish, and about using improved technologies such as artificial fish attractors.

Fish attractors have been used successfully in Asia by artisanal fisheries to catch live bait and tuna. The principle is simple.A structure is placed under the water and as algae begins to grow on it, it attracts small fish, which in turn attract larger fish.

Fish attractors are used extensively by commercial tuna fisheries. Simple, inexpensive structures are now being used by small-scale hook and line fishermen. The fish attractors built in Brazil are floating rafts made of bamboo sticks fashioned in a cylindrical form three metres long and one metre in diameter.

From this construction hangs a comb-like

array of dried coconut leaves and pieces of discarded fishing nets. The fishing nets provide more surface area for drifting organisms on which small fish feed.

A 200-litre drum, filled with concrete, anchors an individual attractor or group, and is attached by steel and polypropylene ropes. The attractor is installed between 100 to 300 metres deep. Once a concentration of tuna and other species occurs, fishermen can harvest as much as 100 to 200 kg per day using hooks and lines.

Larger-scale fishermen use a boat with a light at night to keep the fish concentrated

under the attractor.At dawn, the “light boat” detaches the line of coconut leaves and lets them drift away from the attractor.

Another boat with purse nets surrounds the “light boat” with nets and pulls in the catch. The line of coconut leaves is returned to the attractor to produce another concentration of fish.

Fish attractors can also be made in different shapes and with different materials, such as steel rafts or marker buoys. They are also useful in freshwater lakes and rivers to catch species such as catfish, mudfish, and carp.

In Brazil, data is being collected on fish distribution, abundance and seasonality. As well, local fishermen’s co-operatives are being trained to use fish attractors as part of a fishing programme.

Fish attractors can be made from local materials such as bamboo, coconut branches, steel drums, and concrete. A good knowledge of local fish distribution and abundance is needed, as well as training in using the attractors. Potential users are small-scale fishermen, particularly of tuna and other pelagic species. ■