Establish temporary fisheries closures

How is the evidence assessed?
  • Effectiveness
    30%
  • Certainty
    36%
  • Harms
    10%

Study locations

Key messages

  • Six studies examined the effects of establishing temporary fisheries closures on subtidal benthic invertebrates. One study was in the English Channel (UK), one in the D’Entrecasteaux Channel (Australia), one in the North Pacific Ocean (USA), two in the Mozambique Channel (Madagascar), and one in the North Sea (UK).

 

COMMUNITY RESPONSE (2 STUDIES)

  • Overall species richness/diversity (1 study): One replicated, site comparison study in the English Channel found that sites seasonally closed to towed-gear fishing did not have greater invertebrate species richness than sites where towed-fishing occurred year-round.
  • Mollusc community composition (1 study): One replicated, before-and after study in the D’Entrecasteaux Channel found that temporarily reopening an area previously closed to all fishing for 12 years only to recreational fishing led to changes in scallop species community composition over four fishing seasons.

POPULATION RESPONSE (1 STUDY)

  • Overall abundance (1 study): One replicated, site comparison study in the English Channel found that sites seasonally closed to towed-gear fishing did not have a greater invertebrate biomass than sites where towed-fishing occurred year-round.
  • Crustacean abundance (1 study): One before-and-after, site comparison study in the North Sea found that reopening a site to fishing following a temporary 20-month closure led to lower total abundance but similar marketable abundance of European lobsters compared to a continuously-fished site after a month.
  • Mollusc abundance (5 studies): One replicated, site comparison study English Channel found that sites seasonally closed to towed gear did not have higher abundance of great scallops than sites where towed-fishing occurred year-round. Two before-and after, site comparison studies (one replicated) in the Mozambique Channel found that temporarily closing an area to reef octopus fishing did not increase octopus abundance/biomass compared to before closure and to continuously fished areas. Two replicated, before-and after studies in the D’Entrecasteaux Channel and the North Pacific Ocean found that temporarily reopening an area previously closed to all fishing to recreational fishing only led to a decline in scallop abundance after four fishing seasons and in red abalone after three years.
  • Mollusc condition (3 studies): One replicated, before-and after study in the North Pacific Ocean found that temporarily reopening an area previously closed to fishing led to a decline in the size of red abalone after three years. Two before-and after, site comparison studies (one replicated) in the Mozambique Channel found that temporarily closing an area to reef octopus fishing increased the weight of octopus compared to before closure and to continuously fished areas, but one also found that this effect did not last once fishing resumed.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, site comparison study in 2002 of five sites of mixed coarse seabed off the south Devon coast, English Channel, UK (Blyth et al. 2004) found that sites seasonally closed to towed gear did not have greater invertebrate species richness or biomass, and did not have more great scallops Pecten maximus than sites where towed-fishing occurred year-round. Seasonal and year-round sites had similar average species richness (seasonal: 10–15 vs year-round: 8–10 species/tow), average biomass (1.5–2.4 vs 0.8–1.5 kg/tow), and average abundance of great scallops (1–11 vs 0–2 scallops/tow). In 1978 a zoned fishery management system was established in a 500 km2 area, which included an area where towed-gear and static-gear rotated seasonally. In 2002, five sites were surveyed: two seasonally-towed and three towed year-round. Dredges were towed for 10 mins three times at each site (two standard dredges to collect great scallops >100 mm in length; one scientific dredge for other invertebrates). Species were identified and wet-weighed (individuals combined/species).

    Study and other actions tested
  2. A replicated, before-and after study in 2005–2009 in a sandy seabed area in the D’Entrecasteaux Channel, southeastern Tasmania, Australia (Tracey & Lyle 2011) found that temporarily reopening an area previously closed to all fishing to recreational fishing only led to changes in scallop species community composition over time and a 52% decline in overall scallop abundance after four fishing seasons. Community data were reported as statistical model result. Changes in scallop community composition over time was mostly due to changes in abundance of the scallop Pecten fumatus, which declined by 69% after four fishing seasons. In 2005, an area was reopened to scallop recreational fishing after 12 years of full fishing closure. Scallops (Pecten fumatus, Equichlamys bifrons, Mimachlamys asperrimus) were surveyed once before the first fishing season (in February 2006) and annually for four years after the fishing season (July–August 2006–2009). Twenty-four sites were surveyed in 2006–2007, and an additional 38 (total 62) in 2008–2009. Two divers identified and sized all scallops along a 200 m2 transect at each site. No data prior to the closure are presented.

    Study and other actions tested
  3. A replicated, before-and after study in 2004–2010 in a rocky seabed area in the North Pacific Ocean, northern California, USA (Rogers-Bennett et al. 2013) found that temporarily reopening an area previously closed to fishing led to a decline in abundance and size of red abalone Haliotis rufescens after three years. Abundance of abalone declined by 65% and was lower three years after reopening (0.45 abalone/m2) compared to during closure (1.3 abalone/m2). This was also true for the size of abalone (after reopening: 168 mm; during closure: 172 mm). Five months after closing the fisheries again, the abundance and size of abalone decreased further (abundance: 0.33/m2; size: 166 mm). In July 2004, an area where abalone fishing had been prohibited was reopened to fishing. In May 2010, the area was designated as a marine protected area and closed again to fishing. Red abalone abundance and size were recorded along a total of 83 transects (60 m2) in spring 2004 (prior to reopening fishing – 23 transects), September 2007 (during fishing – 33 transects), and September 2010 (five months after closing fishing again– 27 transects).

    Study and other actions tested
  4. A before-and after, site comparison study in 2004–2005 in a coral reef area in the Velondriake Locally Managed Marine Area, southwestern Madagascar, Mozambique Channel (Benbow et al. 2014a) found that temporarily closing an area to a reef octopus Octopus cyanea fishery did not lead to a significant increase in the weight of octopus, and did not increase their abundance, compared to before closure and to continuously fished areas. Across fishing events during the first spring tide following the temporary closure, the average weight of caught octopus was 64% higher than before closure (before: 719 g; after: 1,120 g) but this was not statistically significant. In addition, the percentage of caught octopus over 2 kg increased from 8% to 20%. However, this increase in weight was not observed across the second spring tide (data not shown). Abundance (as biomass of octopus caught) did not change before and after closure in either temporarily closed sites or continuously fished sites and was similar at all sites (closed before: 3, closed after: 2–3.5; fished before: 2.7, fished after: 2–2.5 kg/fisher/day). An octopus fishery was closed at one site between November 2004 and June 2005 by means of a Dina (a traditional local law). Fishery data, including octopus weight, catch/unit effort and location of landing, were collected on a regular basis across nine nearby villages from September 2004 (before closure) and until at least two spring tides after reopening. These data included the closed site and 14 continuously fished sites (where spear fishing was the only practice).

     

    A replicated, before-and after, site comparison study in 2005–2006 in a coral reef area in the Velondriake Locally Managed Marine Area, southwestern Madagascar, Mozambique Channel (Benbow et al. 2014b) found that temporarily closing areas to a reef octopus Octopus cyanea fishery led to an increase in the weight of octopus, but not abundance, compared to before closure and to continuously fished areas. Across fishing events during the first spring tide following the temporary closure, the average weight of caught octopus was 160% higher at one of the three sites than before closure (before: 436 g; after: 1,136 g). However, this effect was not observed across the second spring tide (data not shown). At the two other closed sites, octopus weight was similar before closure (893 g and 997 g) and directly after reopening (889 g and 988 g). However, on reopening, octopus at all closed sites were 21–56% bigger (by weight; 889–1,165 g) than at fished sites (737 g). Following closure, abundance (as biomass of octopus caught) had increased by 88–146% in the closed sites (before: 1.3–1.6; after: 3–3.2 kg/fisher/day), while abundance did not change at fished sites and was lower (before: 2.4; after: 2.8 kg/fisher/day). This effect was also observed in the following tides. A state-enacted closure of octopus fishery was set across southwest Madagascar between early December 2005 and end of January 2006. This closure was extended at three sites and set between November 2005 and April 2006 by means of a Dina (a traditional local law). Fishery data, including octopus weight, catch/unit effort, and location of landing, were collected on a regular basis across nine nearby villages from September 2004 (before closure) until September 2006 (at least two spring tides after reopening). These data included the closed sites and 14 continuously fished sites (where spear fishing wass the only practice).

    Study and other actions tested
  5. A before-and-after, site comparison study in 2013–2015 of two rock and cobble sites off the Holderness coast, northeast UK, North Sea (Roach et al. 2018) found that reopening a site to fishing following a temporary 20-month closure during wind farm construction led to lower total abundance but similar marketable abundance of European lobsters Homarus gammarus a month after fishing resumed compared to a continuously-fished site. Total abundance was similar at both sites after 20 months of closure and before reopening (reopened: 113; fished: 107 lobsters) but reduced at the reopened site after a month (72), with no change at the fished site (108). Before reopening, the abundance of marketable lobsters (>87 mm) was higher at the reopened site (37) compared to the fished site (12) but decreased at both sites to similar levels following reopening (reopened: 9; fished: 8). In 2014–2015 a 35 km2 windfarm was constructed approximately 10 km offshore. The area was closed to all fishing for 20 months during construction, until August 2015. Lobsters were surveyed at a site inside the windfarm area and a site outside (1 km north) in June 2015 (before reopening) and in September 2015 (after reopening). During each survey, 11–13 strings of 30 baited pots were deployed at each site. Abundance (per string) and size of lobsters (carapace length) were recorded.

    Study and other actions tested
Please cite as:

Lemasson, A.J., Pettit, L.R., Smith, R.K. & Sutherland, W.J. (2020) Subtidal Benthic Invertebrate Conservation. Pages 635-732 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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Subtidal Benthic Invertebrate Conservation

This Action forms part of the Action Synopsis:

Subtidal Benthic Invertebrate Conservation
Subtidal Benthic Invertebrate Conservation

Subtidal Benthic Invertebrate Conservation - Published 2020

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