Action: Cease or prohibit all types of fishing
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- Five studies examined the effects of ceasing or prohibiting all types of fishing on subtidal benthic invertebrate populations. All studies were in the North Sea (Belgium, Germany, Netherlands, UK).
COMMUNITY RESPONSE (2 STUDIES)
- Overall community composition (2 studies): Two site comparison studies (one before-and-after) in the North Sea found that areas closed to all fishing developed different overall invertebrate community compositions compared to fished areas.
- Overall species richness/diversity (2 studies): One of two site comparison studies (one before-and-after) in the North Sea found that areas closed to all fishing did not develop different overall invertebrate species richness and diversity compared to fished areas after three years, but the other found higher species richness in the closed areas after 20 years.
POPULATION RESPONSE (3 STUDIES)
- Overall abundance (2 studies): Two site comparison studies (one before-and-after) in the North Sea found that areas closed to all fishing had similar overall invertebrate abundance and biomass compared to fished areas after three and five years.
- Crustacean abundance (1 study): One before-and-after, site comparison study in the North Sea found that closing a site to all fishing led to similar numbers of lobster compared to a fished site after 20 months.
- Crustacean condition (1 study): One before-and-after, site comparison study in the North Sea found that closing a site to all fishing led to larger sizes of lobster compared to a fished site after 20 months.
OTHER (1 STUDY)
- Overall community energy flow (1 study): One before-after, site comparison study in the North Sea found that, during the 12–14 months after closing an area to all fishing, the invertebrate community structure (measured as energy flow) at sites within the closed area did not change, but that it increased in nearby fished sites.
- Species energy flow (1 study): One before-and-after, site comparison study in the North Sea found that closing an area to all fishing for 12–14 months had mixed effects on species-level energy flow.
Fishing can impact subtidal benthic invertebrates through species removal or habitat damage from fishing gear coming into contact with the seabed (Collie et al. 2000). Ceasing or prohibiting all types of fishing in an area can remove the most direct pressures to subtidal benthic invertebrates, with the aim of enabling previously impacted populations to recover over time (Jack & Wing 2010). Evidence for related interventions is summarised under “Threat: Transportation and service corridors – Cease or prohibit shipping” and “Threat: Biological resource use – Establish temporary fisheries closure”. When this intervention is undertaken within a protected area, evidence is summarised under “Habitat protection – Designate a Marine Protected Area and prohibit all types of fishing”.
Collie J.S., Hall S.J., Kaiser M.J. & Poiner I.R. (2000) A quantitative analysis of fishing impacts on shelf‐sea benthos. Journal of Animal Ecology, 69, 785–798.
Jack L. & Wing S.R. (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.
Supporting evidence from individual studies
A site comparison study in 2004 in areas of soft sediment in the southern North Sea, Netherlands (Duineveld et al. 2007) found that an area closed to all fishing had different invertebrate community composition, and higher species richness, compared to fished areas, after approximately 20 years. Community data were presented as graphical analyses, and richness data were presented as diversity indices. A gas production platform was drilled approximately 20 years prior to the study and a 500 m zone closed to all trawling, established around it. In April 2004, invertebrates were surveyed inside the closed area and in four sites (1 x 1 nm) outside (1.5 nm north, south, east and west of the exclusion zone). Samples were collected using a combination of dredge (6–10 tows/site; invertebrates >7 mm) and sediment cores (seven cores/site; invertebrates >1 mm) at 36–39 m depth. Invertebrates were identified and counted.
A before-after, site comparison study in 2003–2004 in areas of soft seabed sediment in the German Bight, southern North Sea, Germany (Dannheim et al. 2014) found that, during the 12–14 months after closing an area to all fishing, community structure (measured as energy flow) at sites within the closed area did not change, but increased in nearby open sites where fishing occurred. Before fishery closure, community energy flow was similar in the closed (80 kJ/m2) and open sites (66 kJ/m2). After 12–14 months, community energy flow in the closed sites was similar to before (69 kJ/m2), but lower than at open sites where energy flow had increased over time (92 kJ/m2). After 12 months, species-level energy flow was higher in closed areas compared to open areas for 10 of 70 species, and lower for 7 of 70 species. In July 2003 a pilot windfarm platform was constructed, and the surrounding area (500 m radius) closed to all shipping, and as such all fishing. Invertebrates were surveyed at 10 sites inside the windfarm area and 10–18 outside (9 km away) before construction (March–August), and 12–14 months after exclusion (July–October 2004). Invertebrates were collected using a sediment grab (0.1 m2) and a beam trawl at 28 m depth. All were identified, counted, weighed, and their biomass converted to energy values (kJ) using conversion factors. Energy flow was used to compare communities.
A before-and-after, site comparison study in 2008–2012 of multiple sites in an area of sandy seabed in the southern North Sea, 40–50 km off the coast of Belgium (Coates et al. 2016) found that over the three years after closing an area to all fishing, overall community composition changed over time both in closed sites and sites where fishing occurred, and were different overall, but total abundance, biomass, species richness and diversity did not change and remained similar across sites. Data and analyses of community compositions were not reported. Total invertebrate abundance did not change over time and remained similar at sites closed and open to fishing, both before (2008: closed 361 vs fished 436 individuals/m2) and after (2011–2012: 369–1,027 vs 256–458) the closure. This was also true for total biomass (2008: 802 vs 1,656; 2011–2012: 514–5,733 vs 1,392–1,864 mg/m2), species richness (2008: 10.3 vs 10.7; 2011–2012: 10.4–12.3 vs 10.3–14.7 species/sample), and diversity (reported as a diversity index). In 2009/2010 a windfarm was constructed, and an area of approximately 21 km2 closed to all shipping, and as such fishing, established around the windfarm (500 m radius). Invertebrates were surveyed at 6–16 sites inside the windfarm area and 15–25 outside before construction in 2008, and after in 2011 and 2012 (always in September–October). Invertebrates >1 mm were collected using a sediment grab (0.1 m2) at 15–40 m depth, identified, counted, and their dried biomass measured or estimated.
A site comparison study in 2011 of seven areas of soft seabed in the southern North Sea, Netherlands (Bergman et al. 2015) found that overall, an area closed to all fishing had similar invertebrate abundance, biomass, species richness and diversity, compared to six adjacent fished areas, after five years. For each metric, not all data were shown. From core samples, all areas had similar invertebrate abundance (min. 1,096/m2; (closed area); max. 1,778/m2 (fished area)), biomass (min. 32 g/m2 (closed area); max. 17 g/m2 (fished area)), number of species (closed: 16; open: 13–20), and diversity (as diversity indices). From dredge samples, invertebrate abundance and species diversity were similar in the closed area and five of six fished areas, while all areas had similar biomass (min. 61 g/m2 (closed area); max. 134 g/m2 (closed area)) and number of species (closed: 20; fished: 15–21). An offshore wind farm was constructed in 2006, with a 500 m buffer zone approximately 25 km2 around it closed to all shipping, and as such fishing. Invertebrates inside the closed area and at six nearby fished areas were surveyed in February 2011 using two methods. Shorter-lived infauna (>1 mm) were sampled using sediment core (0.078 m2; 16 samples across the closed area; 8 samples/fished areas). Longer-lived infauna and epifauna (>7 mm) were sampled using a dredge (20 m2; 14 samples across the closed area; 6 samples/fished areas). All invertebrates were identified, counted, and weighed (results are for dry weights).
A before-and-after, site comparison study in 2013–2015 of two rock and cobble sites off the northeast coast of the UK, North Sea (Roach et al. 2018) found that 20 months after closing a site to all fishing during wind farm construction, it had similar numbers but larger European lobster Homarus gammarus compared to a fished site. Total abundance increased in both sites and was similar between sites both before (closed: 63; fished: 74 lobsters/string) and after the closure (closed: 93; fished: 107). The proportion of large lobsters (>100 mm) increased in the closed site and was higher than in the fished site (data presented as size-frequency distributions). In addition, abundance of marketable lobsters (>87 mm) was similar between sites before closure (closed: 11; fished: 10 lobsters/string) but was higher in the closed site after 20 months (closed: 23; fished: 10). In 2014/2015 a 35 km2 windfarm construction site approximately 10 km offshore was closed to all fishing for 20 months, until August 2015. Lobsters were surveyed at a site inside the windfarm area and a site outside (1 km north) in June–September 2013 and in June–September 2015. Each time at each site, 23–24 strings of 30 baited pots were deployed. Abundance (per string) and size of lobsters (carapace length) were recorded
- Duineveld G.C.A., Bergman M.J.N. & Lavaleye M.S.S. (2007) Effects of an area closed to fisheries on the composition of the benthic fauna in the southern North Sea. ICES Journal of Marine Science, 64, 899-908
- Dannheim J., Brey T., Schröder A., Mintenbeck K., Knust R. & Arntz W.E. (2014) Trophic look at soft-bottom communities — Short-term effects of trawling cessation on benthos. Journal of Sea Research, 85, 18-28
- Coates D.A., Kapasakali D., Vincx M. & Vanaverbeke J. (2016) Short-term effects of fishery exclusion in offshore wind farms on macrofaunal communities in the Belgian part of the North Sea. Fisheries Research, 179, 131-138
- Roach M., Cohen M., Forster R., Revill A.S. & Johnson M. (2018) The effects of temporary exclusion of activity due to wind farm construction on a lobster (Homarus gammarus) fishery suggests a potential management approach. ICES Journal of Marine Science, 75, 1416-1426
- Bergman M.J.N., Ubels S.M., Duineveld G.C.A. & Meesters E.W.G. (2015) Effects of a 5-year trawling ban on the local benthic community in a wind farm in the Dutch coastal zone. ICES Journal of Marine Science, 72, 962-972