Action

Fit a size-sorting escape grid (rigid or flexible) to a fish trawl net

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Source countries

Key messages

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (0 STUDIES)

BEHAVIOUR (1 STUDY)

  • Use (1 study): One replicated study in a laboratory in Japan found that masu salmon were able to actively escape through a rigid escape grid, irrespective of grid orientation and towing speed, but escape was reduced in dark conditions compared to light.

OTHER (17 STUDIES)

  • Reduction of unwanted catch (14 studies): Eleven of 14 replicated studies (three paired and controlled) in the North Sea, North Atlantic Ocean, Barents Sea, South Atlantic Ocean, Mediterranean Sea, Adriatic Sea, Gulf of Maine and Baltic Sea found that fitting size-sorting escape grids of various types and configurations to fish trawl nets reduced the catches of unwanted small mackerel, small monkfish, non-target whiting and haddock, small hake, unwanted spiny dogfish, non-target herring, prohibited halibut, unwanted sizes of cod and other non-target fish, relative to the retained codend catch or compared to trawls without grids. One study found that fitting size-sorting escape grids of three designs to fish trawl nets reduced the discarded catch of nine of 12 fish species and the overall amount of discarded catch (fish and invertebrates combined), relative to the retained codend catch. One study found that fitting size-sorting escape grids had a mixed effect on the reduction of unwanted and/or undersized fish catch relative to the retained codend catch depending on fish ecological group. The other study found that, compared to standard trawl nets without escape grids, trawls with size-sorting escape grids reduced the overall catch of whiting, but not of undersized whiting.
  • Improved size-selection of fishing gear (3 studies): Two of three replicated studies (two paired and controlled and one controlled) in the North Sea and Norwegian Sea, found that a size-sorting escape grid fitted to trawl nets improved the size-selection of haddock, but not saithe or cod, compared to standard nets without grids. One study found that trawl nets fitted with an escape grid did not improve the size-selection of cod and haddock compared to trawl nets fitted with square mesh escape windows.

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 study in 1992–1999 of four pelagic areas in the North Sea off Norway (Kvalsvik et al. 2002) found that fish trawls fitted with rigid size-sorting escape grids (three designs) allowed a higher proportion of smaller mackerel Scomber scombrus to escape compared to codend catches. Grids of three different designs allowed 8–51% (average 20%) of mackerel of all sizes to escape relative to codend catches (grid: 134–44,000 kg, codend: 128–157,000 kg). The mackerel sorted out by grids had lower average weights (52 to 108 g less) than mackerel retained in the codend and the proportion of mackerel less than 400 g was reduced in all hauls by 4–14% by weight. Data were collected from 12 deployments during separate trials on three commercial and one research vessel from October–December in 1992, 1997, 1998 and 1999. Pelagic mackerel trawl nets were fitted with grids of varying size and construction and either 38 mm (eight tows), 40 mm (two tows) or 42 mm (two tows) bar spacing grid (see paper for specifications). Nets were deployed at 40–142 m depths for 45–140 min. Covers fitted over the grids collected fish escaping through them and a small-mesh inner net in the codend collected the fish that did not escape. Total catch weights in the covers and codend were recorded and subsamples of fish lengths measured.

    Study and other actions tested
  2. A replicated study in 2000 of an area of seabed in the South Atlantic Ocean, off Namibia (Maartens et al. 2002) reported that fitting rigid size-sorting escape grids to a fish trawl reduced the amount of unwanted young monkfish Lophius vomerinus, relative to the retained catches. Data were not tested for statistical significance. Across four grid designs, 59–68% of the monkfish catch was released through the grids and the vast majority were fish smaller than 31 cm (data reported as length frequency distributions). In addition, of the four grids tested, fewer fish were released by the Sort-V single grid with circular openings of 115 mm (59%) and the EX-it grid with circular openings of 130 mm (61%) compared to the Sort-V single grids with circular openings of 120mm (64%) and 130 mm diameter (68%). Data were collected in February 2000 from 40 trawl deployments of 2 h and in 314–379 m depths. Four rigid sorting grids: an EX-it multiple-panel grid with circular openings of 130 mm diameter and Sort-V single grids with circular openings of 115 mm, 120 mm and 130 mm diameter, were tested in a commercial monkfish diamond mesh trawl net (see paper for specifications). Small mesh covers attached over the grids and inside the codend collected the escaped and retained catches. Fish were sorted and depending on size of catch all, or a subsample, of lengths measured.

    Study and other actions tested
  3. A replicated study in 2000 of a pelagic area of the North Sea, Scotland (Eigaard & Holst 2004) reported that a fish trawl fitted with a size-sorting escape grid system reduced the catch of non-target whiting Merlangius merlangus and haddock Melanogrammus aeglefinus in an industrial fishery targeting the smaller-sized species Norway pout Trisopterus esmarki, relative to the overall catch. Data were not tested for statistical significance. Catches of whiting and haddock were reduced in weight by 57% and 37% respectively by the grid. Almost all whiting sorted out were above the minimum landing size (23 cm), whereas for haddock the main sizes of the fish sorted out were below the 32 cm minimum landing size (data reported as length frequency distributions). Relative to retained catch, losses of fish above the minimum landing size were estimated as 46% for whiting and 9% for haddock. Catches of the target species Norway pout were reported to be reduced by 7%. Data were collected in November/December 2000 from 27 valid trawl deployments on a major Norway pout fishing area in the northern North Sea. An industrial trawl fitted with a hinged grid of 24 mm bar spacing was inserted in front of the codend. The top of the grid was covered by a square mesh window of 108 mm mesh to retain larger marketable fish (see paper for specifications). Covers attached over the top of the grid and the square mesh window collected escaped fish and fish retained by the window. Sub-samples of fish from the two covers and the codend catch were sorted and weighed and fish lengths measured.

    Study and other actions tested
  4. A replicated, paired, controlled study in 2001 of two seabed areas in the North Sea off Norway (Graham et al. 2004) found that fish trawls fitted with a rigid size-sorting grid (Sort-V) improved the size-selection of one of three fish species compared to conventional standard trawl nets. The length at which fish have a 50% chance of escape was higher in codends with a grid compared to conventional codends for haddock Melanogrammus aeglefinus (with: 37.2 cm, without: 35.5 cm), but was not statistically different for saithe Pollachius virens (with: 49.1 cm, without: 46.4 cm) and Atlantic cod Gadus morhua (with: 45.6 cm, without: 40.9 cm). In addition, for haddock, but not saithe or cod, this value increased with increasing catch size in the grid codend but was similar for all catch sizes in the standard codend (data reported as statistical models). Fishing trials were carried out in October 2001 on The Patch and Alle Bank fishing grounds off Bergen. Seven hauls were done with each of two codends: a 120 mm diamond mesh codend fitted with a 35 mm rigid sorting grid and 40 mm guiding panel (Sort V system), and a standard 120 mm diamond mesh codend. Selection (i.e. sizes of fish of each species caught) of each codend was calculated by comparing catch to that caught in a small mesh (50 mm mesh) codend trawled simultaneously.

    Study and other actions tested
  5. A replicated, paired, controlled study in 2001 of bottom fishing grounds in the Norwegian Sea off Norway (Kvamme & Isaksen 2004) found that a fish trawl net fitted with rigid a size-sorting escape grid did not improve the size-selection of unwanted Atlantic cod Gadus morhua compared to a conventional trawl net with no sorting grid. The length at which cod had a 50% chance of escape was similar between trawl nets with a sorting grid (53 cm) and conventional trawls without a grid (49 cm) and the selection range (the difference between the lengths at which 25% and 75% of cod were retained) was 10 cm for both the grid and codend. In addition, the proportion of the 34% of cod below the minimum landing size (47 cm) entering the gear was reduced to 8% in the catches with a grid mounted and 12.0% in the catches without a grid. Data were collected in June and July 2001 west of Bear Island. Trawl deployments were done of a standard 135 mm diamond mesh codend fitted with a stainless steel sorting grid (single grid system - modified Sort-V) with 55 mm bar spacing fitted in the upper trawl panel ahead of the codend (9 tows), and a standard 135 mm diamond mesh codend with no grid (18 tows). Covers over the sorting grid escape opening and the codend retained the escaping catch. Full details of trawl designs are provided in the original study.

    Study and other actions tested
  6. A replicated study in 2003 in an area of seabed in the Atlantic Ocean off Portugal (Fonseca et al. 2005) reported that fish trawl nets fitted with a size-sorting escape grid (a modified Nordmøre grid system) had a variable effect on the reduction of unwanted and/or undersized fish catch in a multi-species fishery, and the effect differed by ecological group. Data were not tested for statistical significance. In general, unwanted/undersized individuals of three of three bottom-dwelling (demersal) species escaped in higher proportions by number (unwanted lesser-spotted dogfish Scyliorhinus canicula: 48%, hake Merluccius merluccius: 62%, pouting Trisopterus luscus: 79%) than four of four species pelagic species that inhabit the upper water layers (unwanted blue whiting Micromesistius poutassou: 13%, unwanted longspine snipefish Macroramphosus scolopax: 17%, undersized horse mackerel Trachurus trachurus: 14%, undersized Atlantic mackerel Scomber scombrus: 0%). Of legally sized commercial species, 10% of hake and horse mackerel, 76% of pouting and 9% of Atlantic mackerel were retained. Data were collected in September 2003 from 17 trawl deployments off the north west coast of Portugal at 40–150 m depths. Trawl nets were fitted with a 1.5 × 1 m plastic grid with 30 mm bar spacing in front of the codend. A ‘flapper’ net guided catch to the bottom of the grid. The upper 40 cm had no bars to allow catch not sorted out by the grid into the codend. An inner cover fitted over the grid retained catch that passed through the grid and would otherwise escape under commercial operations via an opening in the net (see paper for gear specifications).

    Study and other actions tested
  7. A replicated study in 2003 of an inshore area in the western Mediterranean Sea, Spain (Sardà et al. 2005) reported that fitting an experimental size-sorting escape grid to a fish trawl net reduced the capture of unwanted, young hake Merluccius merluccius in the hake fishery, relative to the overall catch. Data were not tested for statistical significance. Hake under 21 cm were able to pass through the grid, and the maximum escape rates were for hake under 12 cm, relative to the retained catch not sorted out by the grid (data presented as length frequency distributions and selection curves). Average length at which 50% of hake were retained was 14.2 cm and for all size groups, the escapees accounted for 26% of the hake in weight. In addition, average size-selection range was high, indicating that grid performance was not yet at its best. Data was collected from 10 trawl deployments conducted on a commercial trawler in May 2003. Tow durations were 60–135 min, 3.7 knots and at 40–160 m depths. The trawl net was fitted with a hinged grid 145 x 100 cm, with 20 mm bar spacing in the lower part and four large open rectangles in the top half for larger fish to pass through. Two codends (40 mm mesh) connected to each half of the grid collected the small escaped fish (lower part) and target (large fish) retained (upper part) portions of the catch. Total length of all hake was measured.

    Study and other actions tested
  8. A replicated, paired, controlled study in 2002–2003 of bottom fishing grounds in the Barents Sea, Norway (Jørgensen et al. 2006) found that fish trawl nets fitted with a rigid size-sorting escape grid (Sort-V) reduced the unwanted catch of smaller Atlantic cod Gadus morhua, compared to conventional trawl nets without a grid. In two of two trials, the average lengths at which 50% of cod escaped capture and half were retained (selection length) was larger in trawl nets with grids (55 and 54 cm) than without (44 and 50 cm). In 2002–2003, data were collected from experimental trawl deployments off the coast of Finnmark targeting cod. Two sampling methods were used. In 2002, a conventional 135 mm diamond mesh trawl was tested with (17 tows) or without (14 tows) a rigid 55 mm sorting grid. Small-mesh covers installed over the escape outlet of the grid and the codends collected the escaped and retained catch respectively. In 2003, seven paired tows were done with a twin trawler where one side was fished with a conventional 135 mm mesh trawl net with a sorting grid and the other fished with a fine-mesh inner liner. A further nine paired tows were done in the same way with a conventional net without a grid (see paper for specifications).

    Study and other actions tested
  9. A replicated study in 1997–1999 of a seabed area in the North Sea off Norway (Kvalsvik et al. 2006) found that fish trawl nets fitted with size-sorting escape grids of various configurations allowed unwanted haddock Melanogrammus aeglefinus and other non-target fish to escape capture in an industrial trawl fishery for Norway pout Trisopterus esmarkii, relative to the total catch. In 1997 trials, overall percentages of target and non-target fish sorted out by all grid configurations was 13–58%. For the only non-target species with data, haddock, an average of 44% escaped capture and they were significantly smaller than those retained in the codend (data reported as statistical results). In separate trials in 1998–1999 using different grid/net configurations, averages of 25–73% of unwanted haddock, and 65–100% of eight of eight other non-target species (saithe Pollachius virens, whiting Merlangius merlangus, Atlantic cod Gadus morhua, ling Molva molva, hake Merluccius merluccius, mackerel Scomber scombrus, herring Clupea harengus, tusk Brosme brosme) escaped capture. Data were collected from 35 trawl deployments with grids fitted in 1997 and 60 in 1998–1999. In 1997, different guiding panels and grid bar spacings were tested and in 1998–1999 combinations of grid bar thickness and mesh size of netting where grids were inserted were tested (see paper for full specifications). Escaping fish were collected in a cover attached over the escape opening. Cover and codend fish catches were sampled.

    Study and other actions tested
  10. A replicated study in a laboratory in Japan (Gabr et al. 2007) found that small masu salmon Oncorhynchus masou were able to actively escape through rigid size-sorting escape grids fitted to a finfish trawl, regardless of grid orientation, under simulated trawling conditions, and escape ability was not typically affected by towing speed, but was affected by the light conditions. Across all grid orientations, salmon escape rate through grids was 47–100%. For flat-fitted and forward-sloping grids, more salmon escaped in light conditions compared to dark, regardless of towing speed (light: 87–100%, dark: 47–60%) and for a backward-sloping grid, increasing the speed to 1.5 from 1 knot increased escapes in the dark (to 87% from 67%) so that they were similar to escape rates in the light (100%). In addition, salmon escape through the grids was higher than square mesh panels, for flat and backward-sloping orientations at both light conditions and towing speeds (grids: 47–100%, square meshes: 0–67%) whereas escape through the forward-sloping grids was higher than escaping through the forward-sloping square meshes in the dark at the higher towing speed only. Six trials were conducted for each grid orientation at each towing speed (1 and 1.5 knots), three in dark and three in light conditions. For each trial, five juvenile salmon (12–14 cm length) were released into a circular canal 75 cm wide and 50 cm deep and forced to swim inside a framed net driven around the canal by a motor, to simulate a trawl deployment. The rigid sorting grid (38 mm bar spacing) was fixed to the bottom net frame at three orientations: flat, forward facing or backward facing. Fish were forced to swim for a maximum of 30 min and escapes monitored by video camera. The same trials were done with a square-mesh (60 mm mesh size) panel. The year the study took place is not reported.

    Study and other actions tested
  11. A replicated, controlled study in 2005–2006 of two seabed areas in the Norwegian Sea, off Finmark and Troms, northern Norway (Grimaldo et al. 2008) found that fish trawl nets fitted with a rigid size-sorting escape grid did not improve the size-selection of cod Gadus morhua and haddock Melanogrammus aeglefinnus compared to trawl nets fitted with square mesh escape windows or a large diamond-mesh codend. In nets with a grid, the average length (56.1 cm) at which half of cod were estimated to be retained (selection length) was similar to nets with escape windows (53.9 cm) but lower than a large diamond mesh codend (60.7 cm). For haddock, average selection length was similar between all three codends: (grid: 50.2 cm, escape windows: 50.6 cm, large diamond: 49.9 cm). In addition, all retention lengths were higher than the minimum landing sizes of 47 cm (cod) and 44 cm (haddock). Data were collected from 62 deployments in December 2005–March 2006 of a trawl net with two codends: one an experimental codend and one a control diamond-mesh codend with a small-mesh inner net. Experimental nets were a 135 mm diamond-mesh codend fitted with a 55 mm sorting grid (Sort-V); a 135 mm diamond-mesh codend fitted with two side escape windows; and a codend of 155 mm diamond mesh.

    Study and other actions tested
  12. A replicated study in 2008 of three bottom trawling sites in the North Adriatic Sea, Italy (Sala et al. 2011) found that fish trawl nets fitted with size-sorting escape grids (Turtle excluder devices) typically reduced the amounts of discarded fish catch and overall discarded catch (fish and invertebrates combined), relative to the codend catch. For three of three designs, grids reduced the average catch rates of nine of 12 discarded fish species (see paper for list of species) compared to the total catch that would have been retained if no grids were fitted (with: 0.17–1.27 kg/tow, without: 0.34–2.45 kg/tow), and for three of 12 fish species average catch rates were similar (with: 0.58–1.16 kg/tow, without: 0.58–1.50 kg/tow). Average catches of all discarded catch (fish and invertebrates) were reduced in nets with grids (with: 9–21 kg/tow, without: 25–28 kg/tow). Three different grid designs (flexible, rigid and semi-rigid construction), all with bottom escape openings, were tested in standard fish trawls used in Mediterranean bottom fisheries (see paper for specifications). Catch data was collected from 42 fishing deployments (11–15 per grid) in March 2008. Fish and marine invertebrates escaping through the grid were collected in a cover attached over the grid outlet. Cover and codend catches were pooled to calculate total catch of a ‘control’ net without a grid.

    Study and other actions tested
  13. A replicated study in 2008–2009 of two bottom fishing areas in the Gulf of Maine, USA (Chosid et al. 2012) reported that experimental rigid size-sorting escape grids fitted to a fish trawl net allowed high proportions of unwanted spiny dogfish Squalus acanthias to escape. Overall, more than 88% of spiny dogfish that entered the trawl net were excluded by size-sorting grids, regardless of grid colour or design configuration. However, a black grate with an escape opening in the bottom of the trawl was reported to show the highest dogfish escape ratio (data not tested for statistical difference). Data were collected from 32 deployments of a silver hake Merluccius bilinearis trawl during fishing trials in October–November 2008 and July–August 2009. The trawl nets were fitted with a polyethylene grid, with 51 mm bar spacing, inserted into the extension piece in front of a small diamond mesh (51 mm) codend. Different grid colours (black and white), configurations of grid angle (35° and 45°) and location of the escape opening (top and bottom) were tested. Counts of dogfish were obtained from underwater video (mounted in front of the grid) and codend catches.

    Study and other actions tested
  14. A replicated study in 2007 of a fished area of seabed in the North Sea off northeast Scotland, UK (Eigaard et al. 2012) reported that fish trawl nets fitted with a rigid size-sorting escape grid allowed high proportions of non-target haddock Melanogrammus aeglefinus and whiting Merlangius merlangus to escape and around half of all herring Clupea harengus in an industrial fishery for the smaller-sized species Norway pout Trisopterus esmarkii. Data were reported as percentage escapes and results were not tested for statistical significance. The percentage of haddock and whiting excluded from the trawl by the grid was 93–100% and 81–100% respectively. The percentage of herring that escaped capture was 40–62%. The effect was similar for trawls during the day or night, and for grids facing either forwards or backwards. Loss of target pout was 6–14%. In November/December 2007, data were collected from 14 trawl deployments done on two, nine-day fishing trials on the Fladen Ground, a traditional Norway pout fishing ground. A trawl net fitted with a 180 x 130 cm fibreglass grid with 23 mm bar spacing, mounted at 60° angle, and either facing forwards with a top escape opening (five tows) or backwards with a bottom escape opening (nine tows) was tested. A cover collected catch passing through the escape outlet. Trawls were towed for 8 h at 3.1 knots and 131–144 m depths.

    Study and other actions tested
  15. A replicated study in 2011 of a deep seabed area in the North Pacific Ocean off Washington, USA (Lomeli & Wakefield 2013) reported that fitting a flexible size-sorting escape grid system allowed the escape of prohibited Pacific halibut Hippoglossus stenolepis in a groundfish bottom trawl fishery and, to a lesser extent, unmarketable sizes of other fish species. Data (except halibut length) were not tested for statistical significance. Overall, 62% of the halibut escaped capture through the grid relative to the weight retained in the codend (grid: 308 kg, codend: 192 kg) and they were larger in size (grid: 74.5 cm, codend: 70.0 cm). For the target fish species/groups (see paper for list), between 0–23% of other flatfish, 6–11% of roundfish and 0–77% of skates of unmarketable sizes were sorted out by the grid. In addition, of marketable sizes, an average of 77–87% of other flatfishes, 83–89% of roundfishes and 6–13% of skates of were retained. Trials were carried out using a low-rise flatfish trawl net with a cutback headrope, fitted with a grid system. Data were collected from 30 trawl deployments of 28–30 min, in depths of 113–173 m and at speeds of 2.7–3.2 knots. The grid system was inserted in front of the codend and consisted of two flexible vertical grids (19 ×19 cm openings) to direct fish toward a downward-angled escape panel (see paper for full gear specifications). A cover installed over the escape openings collected escaping fish. Cover and codend catches were sorted and sampled.

    Study and other actions tested
  16. A replicated study in 2014 of an area of seabed in the Pacific Ocean off Oregon, USA (Lomeli & Wakefield 2016) found that a flexible size-sorting escape grid system fitted to a bottom fish trawl net reduced the catches of non-target fish species, and typically retained much of the targeted flatfish catch. Data were not tested for statistical significance. Overall, catches of five groups and species of non-target roundfish and one flatfish (see paper for list of species), relative to the catches retained in the codend, were reduced by 64–99% (grid: 99–5,372 kg, codend: 16–95 kg), and the probability of escape increased with increasing length. For five target flatfish species evaluated, escape rates were 8–32% (grid: 28–1,164 kg, codend: 268–7,089 kg). In June 2014, a total of 38 trawl deployments were completed west of central Oregon. Hauls were 1 h at an average depth of 174 m. A flexible grid system was fitted to a bottom trawl net, consisting of a four-seam tube of netting inserted in front of the codend (see paper for specifications). The two side panels had 5 x 22 cm grid openings to either exclude fish from the trawl via an exit opening or allow fish to pass through to the codend. A cover net attached over the grid opening sampled escaping fish. All fish caught in the cover net and codend were identified and weighed, and fish lengths sub-sampled.

    Study and other actions tested
  17. A replicated study in 2014 of a bottom fishing ground in the western Baltic Sea, northern Europe (Stepputtis et al. 2016) found that fitting a rigid size-sorting escape grid to a fish trawl net resulted in reduced catches of cod Gadus morhua and an increase in the escape of cod of unwanted sizes, in addition to the sizes sorted out by the mesh of the codend. Total numbers of cod that escaped from the net were 3,881 fish (1,608 kg) through the grid and 3,918 fish (1,150 kg) through the meshes of the codend, and the number of cod retained in the codend was 4,715 fish (2,617 kg). In addition, the average length at which half of the cod were likely to escape from each part of the net was 47.9 cm for the grid and 29.7 cm for the codend itself. Data were collected from eight bottom trawl deployments by a research vessel in March 2014 in the Baltic Sea cod fishery. A steel grid, with 50 mm bar spacing, a guiding panel and a top escape opening, was fitted to a standard diamond mesh trawl. A rectangular piece of netting was mounted over the opening to make it less visible to fish and increase fish contact with the grid. Deployments were 90–120 min, towed at three knots. Covers fitted over the grid opening and over the codend collected all cod escaping through them. Cod collected in the two covers and retained in the codend were counted and their lengths measured.

    Study and other actions tested
  18. A replicated, paired, controlled study in 2009 of a seabed area in the southern North Sea, France (Vogel et al. 2017) found that a fish trawl net modified with a flexible size-sorting escape grid caught less whiting Merlangius merlangus overall but did not reduce the amount of undersized whiting compared to a standard trawl net without a grid, in a mixed-species bottom trawl fishery. Catch numbers of whiting across all lengths were generally lower with a grid, and the most caught of any given length was 7,000 fish with a grid and 10,000 fish without (data not statistically tested). However, average whiting length was not statistically different between nets (grid: 27.3 cm, no grid: 27.5 cm). In February 2009, trials were done on two 20–24 m commercial trawlers fishing parallel to each other: one rigged with the test net and one with the standard net (see paper for specifications). A total of 13 paired deployments were completed. Nets were identical apart from the test net had a 1.25 x 0.75 m flexible grid, and vertical bars with 20-mm spacing, and the standard net had no grid but a mandatory 80 mm square mesh panel. Both commercial and non-commercial fish catches were sampled. Total length/fish and weight/species were recorded. Random sub-sampling was done when catches were large.

    Study and other actions tested
Please cite as:

Taylor, N., Clarke, L.J., Alliji, K., Barrett, C., McIntyre, R., Smith, R.K., and Sutherland, W.J. (2021) Marine Fish Conservation: Global Evidence for the Effects of Selected Interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.

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