Alternative Gear
WHAT IS ALTERNATIVE GEAR?
Alternative gear involves changing the type of gear used in a fishery, to one that maintains commercial viability but poses a lower risk to wildlife. Gear switching trials around the world have shown promising results thus far. However, further testing of the effectiveness of alternative gear for different target species is necessary. For gear diversification to happen, major investment would often be required, along with fishermen’s acceptance and compliance.
CURRENT RESEARCH & USE
Gillnets are often associated with higher levels of marine mammal bycatch than other gear types. The FAO have summarised the results of various trials in which longlines, pots and trawls were tested as alternatives to gillnets – this can be accessed here.
- Gillnet vs longline: Generally, there are differences between gillnets and longlines in terms of catch amount, species composition and size selectivity. Longlines do, however, offer a ‘fresher’ catch (as gillnets are soaked for longer), and demand for fresh products has been rising. A further 2020 trial in a small-scale artisanal fishery in Argentina tested longlines as an alternative to gillnets. Longlines resulted in similar catch composition and catch size, with reduced bycatch of Franciscana dolphin.
- Gillnet vs pots: Where entanglement of large whales or other non-target species is unlikely or minimal, fishing with pots occasionally has the potential to eliminate bycatch, particularly in areas where porpoises and dolphins are frequently caught in gillnets. In the Baltic, pot or trap fisheries have been shown to be a viable alternative to gillnet fisheries, for example for cod, and can result in reduced seal bycatch. Pots are floated a distance above the seabed, to position the entrance downstream – increasing catch efficiency – and to ensure the pot moves away when seals attempt to push against the side or top. Work to refine pots for catching Baltic Sea cod while preventing seals from feeding on fish in fishing gear (depredation) has found that doubling the volume and increasing the soak time of pots, and incorporating a holding chamber into the design, can significantly increase catches. It has also been suggested that the long term reintroduction of pots has potential as an alternative gear to tangle nets in Irish crawfish fisheries, although the effectiveness of potting for species such as pollack and hake is unknown.
- Gillnet vs trawls: Whilst trawls have been reported to accidentally catch cetaceans in various parts of the world, levels of bycatch and mortality are generally lower than in gillnets. In cases where the risk of bycatch mortality in trawls is relatively low, trials conducted often focus more on comparing the effect on target catch and less on monitoring the bycatch of marine mammals.
Gillnet vs. jigging: Jigging requires predominantly clear water, so is only viable at certain times of year. When sea conditions are not favourable for jigging, some fishermen in the South West of the UK, for example, deploy gillnets for the same target catch instead. While it is reported as resulting in no cetacean or elasmobranch bycatch, it does not eliminate seal depredation. Jigging as an alternative gear to reduce bycatch does not appear to have been taken up widely, due to the resources and effort it requires in comparison to netting, and so would benefit from research.
- Gillnet vs. small-scale Danish seining (mini seine): Used for demersal fish in Denmark and Norway, with testing currently underway in Germany by the Thünen Institute. It can increase catch value while reducing fuel use, and so far shows low wildlife bycatch and seal depredation, although its use is limited to soft grounds.
This page was last updated on 14.06.23.