Limit fishing activity by vessel size and/or engine power
Overall effectiveness category Awaiting assessment
Number of studies: 1
Background information and definitions
Overfishing leads to volumes of fish being caught that are unsustainable, both ecologically and economically, as well as to damage of fish habitats. Restriction of fishing effort or capacity may therefore help to reduce the effects of overfishing (Tidd 2013). One way to achieve this may be to limit fishing activity according to vessel size and engine power. Larger vessels typically have higher engine power and a greater ability than smaller vessels to operate or tow large and heavy fishing gear. They also have the capacity to travel further afield and for longer durations to engage in fishing activity. Restricting vessel size and engine power in an area may reduce overall fishing effort by limiting the number and type of vessels allowed to fish there. However, in some cases fishers may be permitted to respond to such restrictions by derating the power of their engines in order to continue fishing in an area rather than move out of it (Pascoe & Robinson 1998).
Pascoe S. & Robinson C. (1998) Input controls, input substitution and profit maximisation in the English Channel beam trawl fishery. Journal of Agricultural Economics, 49, 16–30.
Tidd A. (2013) Effective fishing effort indicators and their application to spatial management of mixed demersal fisheries. Fisheries Management and Ecology, 20, 377–389.
Supporting evidence from individual studies
A before-and-after study in 1985–1994 of an extensive area of seabed in the North Sea, northern Europe (Piet & Rijnsdorp 1998) found that excluding fishing vessels (large beam trawlers) with an engine power >221kW from an area for six months a year resulted in increased abundance of commercially targeted but not non-commercially targeted fish over five years, and of two of eight size-groups for both commercial and non-commercial fish overall. In the period after the exclusion (1989–1994), there was no difference in the total abundance of non-commercially targeted fish compared to the period before (1985–1988) (data reported as statistical results). However, total abundance of commercial fish was higher. Numbers of two of eight size groups for both commercial (30–35 and 35–40 cm) and non-commercial fish (25–30 and 30–35 cm) increased after compared to before (see original paper for data/size group). In 1989, an area of 42,000 km2 in the eastern North Sea (“plaice box”) was closed to vessels >221kW engine power from April-September. Fishing with other gear types of <221kW engine power was permitted. Data were collected from beam trawl surveys (8 m beam, eight tickler chains, 40 mm mesh codend) in July-September each year. Trawls were towed for 30 minutes at 4 knots in the periods before (1985–1988) and after (1989–1994) the exclusion.Study and other actions tested