FossTech’s automatic trawl sack expander promotes sustainable fisheries

Trawling may result in fish injury and death. A primary cause is crowding and crushing inside the trawl sack during hauling. Fish mortality rates above 50 per cent have been recorded at high crowding densities. Even fish that are released may not survive due to stress and injury. Studies have shown that the survival rate of fish slipped from a trawl depends on fish density and duration in the trawl before release.

Moreover, a ship’s crew may have difficulty handling a high-density catch as it rises to the surface and expands, thus slowing the hauling process. Fish that die during hauling are considered bycatch, and cannot be used.

FossTech’s pressure operated actuator constricts sack volume when the trawl is deployed, and releases the constriction as the sack is brought closer to the surface. The mechanism is triggered by changes in pressure, which can be pre-programmed to specific depths.

The increased sack space facilitates more careful and efficient handling of the catch, resulting in lower fish mortality. The actuator also helps to improve crew safety by helping to manage the volume of the trawl sack before it is hoisted onboard.

FossTech’s pressure operated actuator helps trawlers to meet and not exceed quotas. This reduces bycatch, as well as time at sea and associated fuel consumption and emissions. By ensuring sufficent sack space, the actuator also helps to keep fish alive after harvesting, which is key to increased quality and profitability.

The global commercial fishing industry market accounted for USD 241 billion in 2017 and is expected to reach USD 439 billion by 2026. Although the demand for seafood is growing, the harmful impacts of commercial fishing, such as overfishing, must be addressed.

FossTech was established in 1997. The company supplies a full range of encapsulated electronics and advanced electromechanical solutions for subsea and other extreme environments.