Cease or prohibit commercial fishing

Supporting evidence from individual studies

1. A replicated, site comparison study in 2006–2007 of 12 rocky seabed sites in the Tasman Sea, Fiordland, New Zealand (Jack & Wing 2010) found that a zone excluding commercial fishing did not have a higher abundance of red rock lobster Jasus edwardsii compared to adjacent fished areas, after up to two years. Lobster abundance was similar in the exclusion zone (2 individuals/250 m²) and the fished areas (1 individual/250 m²). In 2006 and 2007, divers surveyed eight sites within a commercial fishing exclusion zone set in 2005, and four fished sites (at 15 m depth). Red rock lobsters were counted along 50 x 5 m transects (1 transect/site in 2006, 3/site in 2007).

   Study and other actions tested

   Referenced paper

   Jack L. & Wing S. (2010) Maintenance of old-growth size structure and fecundity of the red rock lobster Jasus edwardsii among marine protected areas in Fiordland, New Zealand. Marine Ecology Progress Series, 404, 161-172.

2. A site comparison study in 2004–2008 in two areas of gravelly and sandy seabed on Georges Bank, northwest Atlantic Ocean, USA (Smith et al. 2013) found that an area closed to certain commercial fishing had a higher biomass of invertebrates attached to the seabed (epifaunal), but not a higher total abundance or species richness, compared to a fished area, 10–14 years after closure. Epifaunal biomass was significantly higher in the closed area (33–109 g/L) compared to the fished area (26–57 g/L). Total epifauna abundance was similar in closed (6–15 individuals/L) and fished areas (6–10 individuals/L). The effect of closing commercial fishing on species richness varied with years, but overall across year species richness was similar in both areas (closed: 26–39; fished: 32–41 species). An area on Georges Bank was closed to all commercial fishing gear capable of retaining ground fish (trawls, scallop dredges, gill nets and hook gear) in December 1994. Annually in 2004–2008, one site in the closed area and one site in an adjacent fished area were surveyed at 45–55 m depth. Epifauna were collected using a dredge (2–3 samples/site/year; 6.4 mm mesh liner), identified, counted, and wet-weighed.

   Study and other actions tested

   Referenced paper

   Smith B., Collie J. & Lengyel N. (2013) Effects of chronic bottom fishing on the benthic epifauna and diets of demersal fishes on northern Georges Bank. Marine Ecology Progress Series, 472, 199-217.

3. A site comparison study in spring 2008 of 48 sites in a soft seabed area in the Tasman Sea, New Zealand (Handley et al. 2014) found that sites within an area closed to commercial trawling and dredging for 28 years had different invertebrate communities, and higher invertebrate abundance, biomass and productivity than sites subject to intense fishing. Community data were presented as graphical analyses. Sites closed to fishing had greater invertebrate abundance (particularly large and small sizes, but not medium-size), and higher biomass and biological productivity, compared to fished sites (data presented as effect sizes). The larger, rarer individuals contributed the most to the biomass and productivity estimates within the closed sites. Separation Point exclusion zone was legally closed to commercial fishing and shellfish dredging in 1980. In 2008, sediments were collected from the western and southern edges of the exclusion zone, each with 12 samples on each side (24 samples inside and 24 outside the closed area in total) using a grab (0.07 m²) at 20–30 m depth. Invertebrates (>0.5 mm) were extracted, identified and counted. Biomass and productivity were estimated using size-based conversion factors.

   Study and other actions tested

   Referenced paper

   Handley S.J., Willis T.J., Cole R.G., Bradley A., Cairney D.J., Brown S.N. & Carter M.E. (2014) The importance of benchmarking habitat structure and composition for understanding the extent of fishing impacts in soft sediment ecosystems. Journal of Sea Research, 86, 58-68.