Collected Evidence: Collected Evidence: Cease or prohibit all commercial fishing Eight studies examined the effects of ceasing or prohibiting all commercial fishing in an area on marine fish populations. Two studies were in the Tasman Sea (Australia), and one was in each of the Indian Ocean (Australia), the Mediterranean Sea (Spain), the Greenland Sea (Iceland), the Gulf of Mexico (USA), the South China Sea (China) and the South Atlantic Ocean (South Africa). COMMUNITY RESPONSE (3 STUDIES) Community composition (3 studies): Two before-and-after studies (one site comparison) in the Tasman Sea and South China Sea found that the fish assemblage/species composition was different before and after prohibiting all commercial fishing, in an estuary after two years, and in the nearby wider region surrounding two marine reserves five years after their creation. One site comparison study in the South Atlantic Ocean found no change in species composition between a reserve closed to all commercial fishing for 40 years and unprotected fished areas. Richness/diversity (2 studies): One site comparison study in the South Atlantic Ocean found no difference in overall fish diversity between a protected area closed to all commercial fishing for 40 years compared to unprotected fished areas. One before-and-after study in the South China Sea found that fish species richness decreased in the wider region five years after all commercial fishing was banned in two marine reserves. POPULATION RESPONSE (7 STUDIES) Abundance (7 studies): Two of four site comparison studies (one replicated, one before-and-after) in the Mediterranean Sea, Indian Ocean, south Atlantic Ocean and the Gulf of Mexico found that in protected areas prohibiting all commercial fishing for five years and 40 years there were higher abundances of three of 12 commercially targeted and non-targeted fish species/groups and one of four commercially targeted fish species, compared to unprotected fished areas. One study found mixed effects on fish densities 30–40 years after banning all commercial fishing, varying with level of commercial exploitation, and higher abundances of five of five commercially exploited species. The other study found there was no increase in white seabream and gilthead bream biomass 2–13 years after closure compared to an unprotected fished area, but it was lower than a no-take area protected for over nine years. One before-and-after, site comparison study in the Tasman Sea found that most fish species in an estuary in a marine reserve had a lower abundance two years after it was closed to all commercial fishing than before, as did one of two reference sites in unprotected adjacent estuaries. One before-and-after study in the South China Sea found that in the five years after the creation of two marine reserves with limits on commercial fishing activity, overall fish density in the nearby wider region increased. One replicated, site comparison study in the Tasman Sea found that in areas of a marine reserve closed to commercial trapping, fish abundance varied over 10 years and was higher for some groups than others compared to reserve sites open to trapping. Condition (1 study): One replicated, site comparison study in the Indian Ocean found that in marine reserve areas banning all commercial fishing for five years, overall fish size was bigger compared to fished areas. BEHAVIOUR (1 STUDY) Use (1 study): One replicated, controlled study in the Greenland Sea found that areas closed to commercial fishing (trawling) had higher recaptures of tagged smaller immature cod than adult cod over time compared to trawled areas, indicating they were more likely to have an increased protection from fishing. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2667https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2667Thu, 19 Nov 2020 11:03:46 +0000Collected Evidence: Collected Evidence: Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor Ten studies examined the effects of ceasing or prohibiting mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor on marine fish populations. Two studies were in each of the North Atlantic Ocean (Canada, Portugal), the Indian Ocean (Tasmania, Kenya) and the Mediterranean Sea. One study was in each of the North Sea (Denmark), the Arafura Sea (Australia), the Coral Sea (Australia) and the Gulf of Mexico (USA). COMMUNITY RESPONSE (3 STUDIES)  Richness/diversity (3 studies): Two of three site comparison studies (one replicated and randomized, and one before-and-after) in the North Sea, Indian Ocean and Gulf of Mexico found that the number of fish species, the fish assemblage and overall species richness and diversity (fish and invertebrates combined) varied between areas with different exposures to bottom trawling, and was also dependent on bottom depth and habitat type. The other study reported no effect of closing an area to all towed bottom fishing gears on the species richness of bottom-dwelling fish after 10 years and compared to areas open to trawling.  POPULATION RESPONSE (8 STUDIES) Abundance (5 studies): Two of three replicated studies (one controlled and before-and-after, and two site comparison) and one of two before-and-after studies (one site comparison) in the North Sea, Arafura Sea, North Atlantic Ocean and the Mediterranean Sea found that ceasing or prohibiting fishing with towed bottom gears resulted in higher total fish biomass after 15 years, higher biomass of adult red mullet after 14 years and increased abundances of long-snouted, but not short-snouted, seahorses after one year, compared to openly fished areas. The other two studies found that a ban on towed bottom fishing gears for five and 10 years had no effect on the abundance of bottom-dwelling fish species after closure compared to before, or the abundance and biomass of fish and invertebrate species (combined) compared to areas open to towed gears/trawling. Reproductive success (2 studies): One of two before-and-after studies (one site comparison) in the North Atlantic Ocean and Mediterranean Sea found that after the closure of an area to all bottom-towed fishing gears for 14 years, recruitment of young red mullet had increased. The other study found that an area closed to bottom trawling did not have higher recruitment of young haddock seven years after closure and compared to a trawled area. Survival (1 study): One before-and-after, site comparison study in the North Atlantic Ocean found that closing an area to bottom trawling did not increase the survival of young haddock seven years after closure, and compared to a trawled area. Condition (5 studies): One of four replicated studies (two site comparison and one randomized, site comparison) and one before-and-after study in the Arafura Sea, Mediterranean Sea, Gulf of Mexico and the Indian Ocean found that areas prohibiting bottom towed fishing gears had larger sizes of adult red mullet 14 years after closure than before. Two studies found that the effect on fish size of closing areas to towed bottom gears for 3–6 years or areas with no bottom fishing activity varied between individual fish groups and with habitat type, compared to fished areas. The other two found that areas closed to bottom trawling for five years and 15 years had no effect on the overall size of fish and invertebrate species combined or average fish weight, compared to trawled areas. BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Reduce unwanted catch (1 study): One randomized, replicated, site comparison study in the Coral Sea found no reduction in the biomass of non-commercial unwanted catch (fish and invertebrate discard) or in the number of ‘common’ and ‘rare’ discard species in areas closed to trawling for seven years compared to trawled areas. Catch abundance (1 study): One replicated, before-and-after study in the Indian Ocean found that areas prohibiting beach and all other seine nets for 3–6 years found overall fish catch rates were higher, and catch rates of individual fish groups were variable, compared to unrestricted areas. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2673https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2673Fri, 20 Nov 2020 12:12:24 +0000Collected Evidence: Collected Evidence: Control human activity in a marine protected area with a zonation system of restrictions Eight studies examined the effects of controlling human activity in a marine protected area with a zonation system of restrictions on marine fish populations. Three studies were in the Indian Ocean (South Africa), two were in the Coral Sea (Australia), and one was in each of the Southern Atlantic Ocean (South Africa), the Ligurian Sea (Italy) and the Philippine Sea (Philippines). COMMUNITY RESPONSE (1 STUDY)  Richness/diversity (1 study): One site comparison study in the Philippine Sea found a higher number of fish species in the no-fishing/no access zone of a multi-zoned marine protected area compared to two partially fished zones and unprotected fished areas 10 to 15 years after implementation.  POPULATION RESPONSE (4 STUDIES) Condition (4 studies): Two of four site comparison studies in the southern Atlantic Ocean, Ligurian Sea, Indian Ocean and the Coral Sea found that controlling human activity in marine protected areas with a zonation system of restrictions resulted in larger average lengths of steentjies and three seabream species three years after implementation compared to unprotected fished areas, and lengths were largest within a no-take zone than a partially fished zone. Two other studies found larger sizes of four of four coral reef fish in a zone where nearly all fishing is prohibited compared to an adjacent zone with fewer fishing restrictions two to seven years after protection, and of two of six fish feeding groups in no-entry zones compared to both no-take and fished zones protected between 10 and 20 years. Abundance (6 studies): Two of four site comparison studies (one replicated) in the Ligurian Sea, Philippine Sea and the Coral Sea found that controlling human activity in protected areas with a zonation system of restrictions resulted in a greater biomass and/or abundance of fish species after 3–15 years compared to unprotected areas outside, and between the zones fish abundance varied with the level of restriction and between individual fish groups and sizes. The other two studies found higher density, biomass, and abundance of fish in non-fished zones (no-entry and no-take) compared to fished zones inside areas protected for 10 to 27 years depending on region, but the effect varied between fish feeding groups, zone protection level and reef region. One site comparison study in the Indian Ocean found higher abundances of four of four reef fish species in a zone where nearly all fishing is prohibited, compared to an adjacent zone with fewer fishing restrictions. One site comparison study in the Southern Atlantic Ocean found that steentjies in a protected zone closed to fishing but open to other recreational activities had a different age and sex structure to a fished multipurpose zone, and both were different to a distant unprotected fished site with low steentjie exploitation. BEHAVIOUR (2 STUDIES) Use (2 studies): Two site comparison studies in the Indian Ocean found that in marine protected areas with zonation systems of activity controls, most of the individuals of the reef fish species tagged and released inside the protected areas were recaptured again at almost the same locations over the following nine or four years, and mainly in the zones where all or nearly all fishing was prohibited for up to 20 years, indicating increased protection from fishing. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2674https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2674Fri, 20 Nov 2020 16:38:07 +0000Collected Evidence: Collected Evidence: Cease or prohibit all types of fishing in a marine protected area Seventy-nine studies examined the effects of ceasing or prohibiting all types of fishing in a marine protected area on fish populations. Fifteen studies were in the Indian Ocean (Kenya, Tanzania, South Africa, Mozambique, Madagascar, multiple African countries, Australia). Twelve studies were in the Mediterranean Sea (Spain, France, Italy). Ten studies were in the Pacific Ocean (New Zealand, USA, Hawaii, New Caledonia, Costa Rica, Tonga, Vanuatu, Solomon Islands). Seven studies were in each of the Coral Sea (Australia, Vanuatu), the Tasman Sea (New Zealand, Australia) and the Atlantic Ocean (Brazil, USA, Puerto Rico, Argentina, South Africa, UK, Canary Islands, Portugal, Turks and Caicos Islands). Four studies were in the Philippine Sea (Philippines). Three studies were in the Caribbean Sea (Belize, Puerto Rico). One study was in each of the Gulf of Mexico (USA), the Java Sea (Indonesia), the Pacific and Indian Oceans (multiple countries), the Sulu Sea (Malaysia) and the North Sea (Norway). Six studies were reviews of marine reserves (New Zealand, Latin America/Caribbean, regions unspecified and across the world).  COMMUNITY RESPONSE (26 STUDIES)  Community composition (7 studies): Seven site comparison studies (two replicated, and one before-and-after) in the Mediterranean Sea, Indian Ocean, Philippine Sea and the Atlantic Ocean found that protected areas where all fishing had been prohibited for between three and 16 years, had a different fish community composition, compared to fished areas.  Richness/diversity (22 studies): Fourteen of 20 site comparison studies (eight replicated, one replicated and paired, and one before-and-after) in the Indian Ocean, Mediterranean Sea, Philippine Sea, Tasman Sea, Atlantic Ocean, Caribbean Sea, Coral Sea and the Pacific Ocean, found that marine protected areas that had prohibited all fishing for between one to more than 25 years, had higher fish species/richness compared to fished areas. Six studies found similar fish species/richness between one and 20 years after all fishing was banned in protected areas, compared to fished areas. One systematic review in the Atlantic and Pacific Oceans found no difference in species richness between unfished protected areas and fished areas. One replicated, site comparison study in the Indian Ocean found that the effects of prohibiting all fishing on fish species richness/diversity after 15 years varied with the sampling method used. POPULATION RESPONSE (66 STUDIES) Abundance (64 studies): Thirty of 54 site comparison studies (18 replicated, eight replicated and paired, two before-and-after, one paired and before-and-after, and one replicated and before-and-after) in the Indian Ocean, Atlantic Ocean, Mediterranean Sea, Pacific Ocean, Tasman Sea, Coral Sea, Philippine Sea, Caribbean Sea, Gulf of Mexico, and the Sulu Sea, found that marine protected areas that had been prohibiting all fishing for up to 25 years or more, had higher abundances (density and/or biomass) of all fish (total fish biomass, total fish density), fishery targeted fish species, non-fishery targeted fish species and all or most of the individual fish species/groups monitored, except fish densities (all or most) and non-fishery targeted species, compared to unprotected fished areas and/or partly-fished protected areas. The studies also found that in some cases where the total fish biomass or densities were higher in no-fished areas, the effect varied between individual groups of fish based on species family and/or position in the food chain, commercial target and non-target species, fish sizes, depth and habitat types. Eight studies found that inside protected areas prohibiting all fishing there were similar abundances of all fish, and all or most of the individual fish species/groups monitored, compared to fished areas between one and 20 years after implementation. The other sixteen studies found that the effect of prohibiting fishing in protected areas for three to 20 years on fish abundance varied between fish species or groups and on their fished status (fishery target or non-target) and/or position in the food chain. One also found that the effect varied with size or age of the protected areas. Five of six reviews (three systematic) across the world, in the Pacific and/or Atlantic Oceans and in unreported regions found that non-fished marine reserves with one to 27 years of protection had higher abundances of all fish, all fish and invertebrates combined and blue cod compared to fished areas, but there were differences between species/groups and fishing intensity outside reserves. The other review found that fish abundance varied between species in no-take marine reserves between one and 25 years old, and was affected by food chain position, level of exploitation and duration of protection. One replicated study in the Pacific Ocean found a long-term decline in the abundance/presence of eight of 12 shark and ray species inside an established (>15 years) no-fishing protected area, however enforcement was poor. One before-and after, site comparison study in the Pacific Ocean, found no differences in overall fish abundance between a marine reserve closed permanently to fishing for five years and a closed area that was harvested for two years during the same period. One site comparison study in the Coral Sea found that in a no-take zone of an area protected for at least 10 years, fish abundance of four of six fish groups were similar to no-entry and fished zones, but two had lower abundance than the no-entry zone. One replicated, paired, site comparison study in the Tasman Sea found that in a non-fished marine park zone abundance of commercially targeted fish was higher than partly fished zones but lower than unprotected areas after four to eight years. Reproductive success (1 study): One site comparison study in the Mediterranean Sea found more eggs of four commercially targeted fish species inside a non-fished marine reserve enforced for three years than in fished areas outside the reserve. Survival (1 study): One site comparison study in the Atlantic Ocean found that prohibiting all fishing in a marine protected area for three years resulted in similar survival of red hind grouper, compared to fished areas. Condition (20 studies): Two global review studies (one systematic) and two systematic reviews in the Pacific Ocean and the Atlantic and Pacific Oceans found that prohibiting all fishing in marine protected areas for one to 27 years resulted in larger fish overall and larger blue cod compared to fished areas, but there were differences between individual fish families or species. Eight of 11 site comparison studies (four replicated, one before-and-after, one paired, and one replicated and paired) in the Tasman Sea, Pacific Ocean, Indian Ocean, Mediterranean Sea, Atlantic Ocean, Java Sea and the Philippine Sea, found that non-fished protected areas had larger fish overall and larger individuals of all or most of the fish species/groups monitored, compared to fished areas, after one to 22 years. The other three studies found similar fish sizes of all or all but one species, compared to fished areas one to 16 years after all fishing was prohibited. Three site comparison studies (one replicated) in the Coral Sea, Caribbean Sea and the Atlantic Ocean found that fish size in protected areas that had not been fished for six to more than 20 years, varied between fish species or food chain groups. One site comparison study in the Atlantic Ocean found that red hind grouper were larger, but had similar growth, in an area protected from fishing for three years compared to fished areas. One site comparison study in the Atlantic Ocean found that young lemon sharks in areas protected from fishing for 20 years had similar growth rates, but lower condition, than sharks in unprotected fished areas. BEHAVIOUR (2 STUDIES)  Behaviour change (2 studies): One replicated, site comparison study in the Pacific and Indian Oceans found that surgeonfish and parrotfish inside established protected areas where fishing was prohibited, showed a similar avoidance response to fishing gears as in fished areas, and this increased with increasing fishing intensity outside the protected areas. One replicated, site comparison study in the Indian Ocean found that in non-fished areas protected for one and 24 years, fish grazing rates were higher compared to fished areas.  OTHER (15 STUDIES) Use (7 studies): Four of six site comparison studies in the Pacific Ocean, Atlantic Ocean and the Tasman Sea found that marine protected areas where all fishing had been prohibited for at least five to 15 years, were used for a large proportion of time by shark and ray species and commercially important reef fish species, compared to fished areas, thus were provided protection from fishing. Two other studies found that time spent inside areas closed to all fishing for 20 years and over 30 years, varied between species and with size for three shark species and with size for giant trevally. One replicated study in the Indian Ocean found that most individuals of five fish species remained inside a marine reserve zone closed to fishing over a nine-year period. Catch abundance (2 studies): One of two site comparison studies in the Mediterranean Sea and Pacific Ocean found that commercial fish catch rates in small-scale traditional fisheries were highest closest to a marine reserve closed to all fishing for 22 years, and decreased with increasing distance from the reserve. The other study found that there was no increase in fish catch rates in commercially landed catch in the five years after a no-fishing zone was implemented in a co-managed protected area. Stock biomass (1 study): One replicated, site comparison study in the Indian Ocean found that the stock biomass (the harvested portion of the population) of reef fish species was highest in enforced protected areas closed to all fishing, compared to various other area management regimes.  Fishing mortality (2 studies): Two site comparison studies in the North Sea and Pacific Ocean found that prohibiting fishing in protected areas resulted in reduced commercial fishing mortality of corkwing wrasse tagged inside non-fished marine reserves compared to fished areas, and that the overall fishing mortality of grey reef sharks tagged inside protected areas was low.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2682https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2682Sat, 28 Nov 2020 14:35:06 +0000Collected Evidence: Collected Evidence: Attach an electropositive deterrent to fishing gear Nine studies examined the effect of attaching an electropositive deterrent to fishing gear on marine fish populations. Three studies were in the Atlantic Ocean (USA, Canada, Bahamas). One study was in each of the Gulf of Alaska (USA), the South Pacific Ocean (Australia) and the Tasman Sea (Australia). One study was a global systematic review and two studies were in laboratory facilities (USA).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (4 STUDIES) Behaviour change (4 studies): Three of four replicated studies (one paired and controlled, one randomized and controlled, one randomized, and one controlled) in the Atlantic Ocean, Tasman Sea, and in laboratory conditions, found that the presence of potentially deterrent materials attached near the bait reduced the frequency of feeding attempts and bait consumption of spiny dogfish, great hammerhead and draughtboard sharks compared to the absence of deterrent materials. The other study found that a potentially deterrent material did not reduce bait consumption by bonnethead and young lemon sharks compared to non-deterrents. One of the studies also found that the bait consumption behaviour of commercially valuable Pacific halibut was unaffected by deterrent materials. OTHER (5 STUDIES) Reduction of unwanted catch (5 studies): Two of four replicated, controlled studies (one randomized) in the Gulf of Alaska, the Pacific Ocean and the Atlantic Ocean found that fishing gear (longlines and traps) fitted with electropositive deterrent materials caught fewer unwanted spiny dogfish, longnose skate, sharks and rays, and fewer undersized halibut, compared to standard fishing gear or gears with non-deterrent materials. The other two studies, and a global systematic review found that electropositive deterrents on fishing gear resulted in similar catches of unwanted spiny dogfish, sharks (total catch), blue shark and sharks and rays (total catch), compared to gear with no deterrents. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2696https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2696Thu, 03 Dec 2020 12:05:21 +0000Collected Evidence: Collected Evidence: Use a larger mesh size Forty-two studies examined the effects of using a larger mesh size of fishing net on marine fish populations. Ten studies, and one review, were in the Atlantic Ocean (UK, Portugal, USA). Eight studies were in the Aegean Sea (Greece, Turkey). Five studies were in the North Sea (UK, Netherlands, France, North Europe) and three were in the Tasman Sea (Australia). Two studies were in each of the Mediterranean Sea (Italy, Turkey), the Pacific Ocean (USA, Chile), the Skagerrak and Kattegat (Northern Europe) and the Gulf of Mexico (Mexico). One study was in each of the English Channel (UK), the Bering Sea (USA), the Baltic Sea (Finland), the Caribbean Sea (Barbados), the Persian Gulf (Kuwait), the Bristol Channel (UK), the Barents Sea (Norway) and the Arabian Sea (India).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Survival (3 studies): One of three controlled studies (one replicated and paired, and one replicated) in the Atlantic Ocean, Baltic Sea and Bristol Channel found that larger mesh sizes improved the post-capture survival of skates and rays compared to smaller meshes. The other two found similar post-capture survival in haddock, whiting and small herring between trawl nets with larger mesh and nets of smaller mesh size. Condition (1 study): One replicated, paired, controlled study in the Bristol Channel reported that the condition of skates and rays at capture was better with a larger trawl codend mesh size compared to a smaller mesh. BEHAVIOUR (0 STUDIES) OTHER (41 STUDIES) Reduction of unwanted catch (21 studies): Fifteen of 20 replicated studies (five controlled, two paired, eight paired and controlled, one randomized and one randomized and controlled) in the North Sea, Skagerrak/Kattegat, Aegean Sea, Caribbean Sea, Mediterranean Sea, Atlantic Ocean, Tasman Sea, Gulf of Mexico, Pacific Ocean, Bering Sea and the Bristol Channel found that using a larger mesh size in a fishing net (various trawls, gillnets, seines and trammel nets) reduced the catches of unwanted (small/undersized, non-commercial, discarded) fish or fish and invertebrates combined, compared to nets with standard/smaller mesh sizes. One study found that amounts of unwanted fish were reduced with larger mesh at smaller catch sizes but were similar between large and small meshes at larger catch sizes, and one found that increasing a trawl codend mesh size reduced the unwanted catch of one of two fish species compared to a standard mesh. Three found that larger mesh sized fishing nets did not typically reduce the unwanted fish catch compared to nets of smaller mesh sizes. One study found that increasing both the mesh size and minimum size limit reduced catches of the youngest fish. Improved size-selectivity of fishing gear (23 studies): Nineteen of 21 replicated studies (eight controlled, four paired and controlled, three randomized and controlled, and one paired) and one review, in the North Sea, Aegean Sea, Baltic Sea, Pacific Ocean, Atlantic Ocean, Gulf of Mexico, Tasman Sea, Arabian Sea, Persian Gulf, Barents Sea and the Mediterranean Sea found that larger mesh sizes (both diamond and square) of the netting of various gear types improved the size-selectivity for all fish species assessed and in one, for two of three fish species, compared to smaller mesh sizes. One study found that size-selectivity for fish was not improved with larger mesh size in the netting of fish traps. The other found that increasing the codend mesh size of trawls fitted with size-sorting escape grids resulted in similar size-selectivity of the codend for fish compared to smaller codend mesh sizes. One controlled study in the English Channel found that a trawl net codend with a larger size of square mesh had similar size-selectivity for Atlantic mackerel as a smaller diamond mesh codend. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2697https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2697Thu, 03 Dec 2020 19:56:32 +0000Collected Evidence: Collected Evidence: Use a different hook type Twenty-five studies examined the effect of using a different hook type on marine fish populations. Nine studies were in the Atlantic Ocean (Portugal, South Africa, USA, Brazil, Portugal, Iceland), six studies were in Pacific Ocean (New Zealand, Japan, Costa Rica, Hawaii, Fiji) and two studies were in the Mediterranean Sea (Spain, Italy). One study was in each of the Barents Sea (Norway), the Denmark Strait (Greenland), the Coral Sea (Australia) and the Strait of Gibraltar (Spain/Morocco). Four studies were reviews (worldwide, Atlantic and Pacific Oceans). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (10 STUDIES) Survival (10 studies): Four of seven replicated, controlled studies in the Atlantic Ocean, Pacific Ocean and Coral Sea and two of three worldwide systematic reviews, found that using different hook types in longline or recreational fisheries, including sizes, styles and other modifications to hooks, reduced the incidence of fish hook injuries (associated with higher post-release mortality), and reduced the capture mortality of some species of unwanted sharks and rays and non-target billfish species, compared to conventional hooks or other hook types. The other four studies found that using a different hook type did not reduce the post-release mortality of young sea breams, or the capture mortality of sharks species and non-target fish species, but did reduce the incidence of deep-hooking in some cases. BEHAVIOUR (0 STUDIES) OTHER (23 STUDIES) Reduction of unwanted catch (20 studies): Eight of 16 replicated studies (13 controlled, one randomized) in the Atlantic Ocean, Pacific Ocean, Barents Sea, Mediterranean Sea, Denmark Strait and Coral Sea, found that using a different hook type, including different sizes, styles and hook modifications, reduced the unwanted catch in longline and recreational hook fisheries of non-commercially targeted and targeted fish species, small non-target fish species, overall fish catch, overall discarded bony fish catch but not sharks and rays, undersized haddock, two of three unwanted fish species, non-target sharks and rays and non-target rays and sailfish, compared to standard hooks or hooks of other types. Seven studies found that changing hook type did not reduce the unwanted catch of young or non-target fish species, unwanted sharks and rays, unwanted blue shark, unwanted roughhead grenadier or non-target pelagic stingray and silky shark, compared to standard or other hook types. The other study found that catch rates of young groupers, and non-target fish and shark species varied with hook design, and larger hooks caught fewer non-target fish species overall, but more undersized grouper and sharks compared to other hook types. Four global systematic reviews found that hook style did not affect the unwanted catch of billfish species, sharks and rays or sharks, compared to standard styles. Improved size-selectivity of fishing gear (3 studies): Two of three replicated studies in the Atlantic Ocean and Strait of Gibraltar, found that increasing hook sizes improved the size-selectivity (by increasing the average catch length) of hottentot and black spot seabream compared to smaller hook sizes. The other study found that a different hook size improved size selectivity for two of five commercially targeted fish species and was also affected by bait size. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2698https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2698Tue, 08 Dec 2020 15:46:56 +0000Collected Evidence: Collected Evidence: Use a different bait type Eleven studies examined the effects of using different bait on marine fish populations. Two studies were global systematic reviews. Three studies were in the North Atlantic Ocean (USA, Iceland).Two studies were in the South Pacific Ocean (New Zealand). One study was in each of the Norwegian/Barents Seas (Norway), the Barents Sea (Norway), the Denmark Strait (Greenland) and the Mediterranean Sea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One replicated study in the South Pacific Ocean and one global systematic review found that using different bait species did not reduce hooking injuries (associated with higher post-release mortality) of undersized snapper or sharks and rays, and did not increase survival of sharks and rays on gear retrieval. BEHAVIOUR (0 STUDIES) OTHER (10 STUDIES) Reduction of unwanted catch (10 studies): Six of eight replicated studies (three controlled and one randomized) in the Norwegian/Barents Seas, Barents Sea, Denmark Strait, North Atlantic Ocean, Mediterranean Sea and the South Pacific Ocean, found that using a different bait type (including size, species and manufacture method) reduced the unwanted catches of undersized haddock (although in one case in only two of six comparisons), Atlantic cod and other unwanted or non-target fish catch, but unwanted catches of torsk and ling were similar, compared to standard or other bait types. Two other studies found no reduction in unwanted catches of pelagic stingray and overall unwanted fish with different bait types. Two systematic global reviews found that using different bait types did not affect the number of unwanted sharks and rays caught. Improved size-selectivity of fishing gear (1 study): One replicated study in the Denmark Strait found that using a different bait species increased the size-selectivity of commercially targeted Greenland halibut. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2700https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2700Thu, 10 Dec 2020 14:26:24 +0000Collected Evidence: Collected Evidence: Modify fishing trap/pot configuration Twenty-three studies examined the effects of modifying fishing trap or pot configuration on marine fish populations. Five studies were in the Atlantic Ocean (USA, Brazil, Canary Islands, Canada). Three studies were in each of the Bothnian Sea (Sweden), the Baltic Sea (Poland, Sweden), the Tasman Sea (Australia) and the Indian Ocean (Kenya, South Africa). One study was in each of the Kattegat (Denmark), the Mediterranean Sea (Spain), the Adriatic Sea (Italy), the Southern Ocean (Australia), the Pacific Ocean (Canada) and the Barents Sea (Norway).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, controlled study in the Bothnian Sea found that survival of small herring escaped from a pontoon fish trap through a size-sorting grid was similar to trap-caught herring that did not pass through a grid. BEHAVIOUR (0 STUDIES) OTHER (22 STUDIES) Reduction of unwanted catch (20 studies): Sixteen of 20 replicated studies (11 controlled, one randomized, paired and controlled, one randomized and controlled, two paired and controlled and one randomized) and one before-and-after study in the Atlantic Ocean, Baltic Sea, Mediterranean Sea, Southern Ocean, Tasman Sea, Adriatic Sea, Bothnian Sea, Indian Ocean, Pacific Ocean, the Kattegat and the Barents Sea, found that modifications to trap configuration (various, including using a different trap type, increased mesh size and fitting an escape device) reduced the unwanted (undersized, discarded or non-commercial target) catches of fish (overall, or all of multiple study species), brown trout, black sea bass, herring, bluethroat wrasse and leatherjacket, cod, protected rockfishes, whitefish, black sea bass, American eel and winter flounder, sharks/rays and of salmon and rainbow trout in one of two cases, compared to unmodified conventional traps or traps of other designs. One of these also found that the number of unwanted species (fish and invertebrates) was lower in modified traps. Three other studies, found that trap modification or type had no effect on unwanted catches of white croaker, non-commercial fish or undersized Atlantic cod, and non-target haddock catches were increased. However, one of these also reported that traps (creels) did not catch high proportions of immature fish, unlike bottom trawls. Improved size-selectivity of fishing gear (4 studies): Three of four replicated studies (two controlled and one randomized, paired and controlled) in the Baltic Sea, Tasman Sea, Indian Ocean and Atlantic Ocean found that traps or pots modified with a square mesh escape window or larger mesh sizes improved the size-selectivity of Atlantic cod, black sea bass and most fish species compared to smaller mesh and/or standard gear. The other found that increasing mesh size of a trap escape panel had no effect on size-selectivity of panga. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2702https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2702Mon, 14 Dec 2020 10:32:58 +0000Collected Evidence: Collected Evidence: Modify the design or configuration of trawl gear (mixed measures) Nineteen studies examined the effects of modifying the design or configuration of trawl gear on marine fish populations. Seven studies were in the Clarence River estuary (Australia), three studies were in each of the Mediterranean Sea (Turkey) and North Sea (UK), two studies were in the North Pacific Ocean (USA), and one study was in each of the South Pacific Ocean, the Skagerrak and Baltic Sea (Denmark/Sweden), the Atlantic Ocean (USA) and the Coral Sea (Australia).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (19 STUDIES) Reduce unwanted catch (16 studies): Twelve of 16 replicated studies (seven paired and controlled, five controlled, and two paired) in the Clarence River estuary, South Pacific Ocean, North Pacific Ocean, Mediterranean Sea, Skagerrak and Baltic Sea, Atlantic Ocean, North Sea and the Coral Sea, found that various modifications to trawl gear, including changes to the trawl wires, number of nets, codend number, footrope configuration, front trawl body panels, codend netting layers, spreading mechanism, method of weaving, knot orientation or using a new overall trawl design, resulted in reduced unwanted catches of non-target and/or discarded fish species or sizes, and of all sizes of four of seven commercial species, compared to standard unmodified trawl gear or other trawl designs. One of these also found increased catch rate of one commercial species and for another two species the effect varied with fish size. Two studies found that modified trawl gear reduced the unwanted catch of only a small proportion of the number of individual fish species caught compared to other trawl configurations, and also that unwanted fish catches varied between day/night. One study found that different trawl configurations had mixed effects on the numbers and sizes of non-target fish catch. The other study found no reduction in catches of discarded finfish between a modified and standard trawl codend. Improved size-selectivity of fishing gear (5 studies): Five replicated, controlled studies in the North Sea and Mediterranean Sea found that various modifications to trawl gear, including changes to the length of the extension piece, the codend strengthening bag, the method of weaving, the number of codend layers and overall design improved the size-selectivity for unwanted (non-target/discarded) fish species or sizes, and annular seabream in one of two cases, compared to unmodified standard trawl gear or other design configurations. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2704https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2704Thu, 17 Dec 2020 11:29:15 +0000Collected Evidence: Collected Evidence: Decrease the circumference or diameter of the codend of a trawl net Thirteen studies examined the effects of decreasing the circumference or diameter of a trawl codend on marine fish populations. Four studies were in the Tasman Sea (Australia) and three studies were in the North Sea (UK, Norway). Two studies were in the Adriatic Sea (Italy) and two were in the Baltic Sea (Denmark/ Germany). One study and one review were in the Northeast Atlantic Ocean (Northern Europe).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (13 STUDIES) Reduction of unwanted catch (6 studies): Two of six replicated, controlled studies (three paired, and one randomized and paired) in the Tasman Sea, Adriatic Sea and Northeast Atlantic Ocean found that bottom trawl nets of smaller circumferences reduced discarded catch of fish in three of five cases and of total discarded catch (fish and invertebrates) in one of two areas, but not overall, compared to standard trawls. Two studies found that reduced circumference codends reduced non-target or discarded fish catch in three of 12 cases and for one of four species. The two other studies found that discarded fish catch was not reduced in smaller circumference codends. Improve size-selectivity of fishing gear (8 studies): Four of eight replicated, controlled studies (one paired) in the North Sea, Adriatic Sea and Baltic Sea, and one review in the Northeast Atlantic Ocean, found that decreasing the circumference or diameter of the codend of trawl gear (bottom trawls and seines) improved the size-selectivity of haddock, Atlantic cod, whiting and European hake and red mullet, compared to larger circumferences/diameters. One also found the effect was the same across two codend mesh sizes, and one also found the effect was greater in diamond mesh with the netting orientation turned by 90° compared to standard diamond mesh. Two studies found that a decrease in codend circumference/diameter improved size-selectivity of haddock and saithe in one of two cases, and of one of three fish species. The other study found that a smaller circumference codend reduced size-selectivity of the gear for one of three fish species and was similar for the other two. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2706https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2706Thu, 17 Dec 2020 14:51:11 +0000Collected Evidence: Collected Evidence: Use a square mesh instead of a diamond mesh codend in a trawl net Twenty-six studies examined the effects of using a square mesh instead of a diamond mesh codend in a trawl net on marine fish populations. Five studies were in the North Atlantic Ocean (Canada, Portugal, USA), four were in the Aegean Sea (Greece, Turkey), three were in the Mediterranean Sea (Spain) and the Tasman Sea (Australia), two studies were in each of the English Channel (UK), the Adriatic Sea (Italy) and the South Pacific Ocean (Australia, Chile), and one study was in each of the Greenland Sea (Iceland), the North Pacific Ocean (USA), the Bristol Channel (UK), the Kattegat and the Skagerrak (Denmark) and the Coral Sea (Australia).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One of two replicated, paired, controlled studies in the Aegean Sea and Bristol Channel found that the short-term survival of two of six fish species was higher after escaping through a square mesh compared to a diamond mesh codend. The other study reported that skate caught in a square mesh codend had a higher overall survival likelihood than those caught in a diamond mesh codend. BEHAVIOUR (0 STUDIES) OTHER (25 STUDIES) Reduction of unwanted catch (16 studies): Ten of 16 replicated, controlled studies (including five paired, three randomized and three randomized and paired) in the Greenland Sea, Aegean Sea, Atlantic Ocean, Tasman Sea, Pacific Ocean, Mediterranean Sea, English Channel, Bristol Channel and Coral Sea, found that square mesh codends reduced the unwanted (non-target or non-marketable/discarded) catches of all fish species monitored, young individuals of half or most commercially targeted fish, total unwanted catch (fish and invertebrates), and discarded fish in deeper but not shallower fishing areas, compared to diamond mesh codends; and two of those studies also found that there was a variable effect on unwanted catch between individual fish species/groups. Four studies found no reduction in catches of unwanted small rockfish and flatfish, three of four commercially important bottom fish species, total unwanted catch (fish and invertebrates), or the total number of unwanted species (fish and invertebrates), compared to diamond mesh codends. One study found that square mesh codends retained more fish overall than diamond mesh but varied for individual species by fish shape and size. One study found that unwanted fish catch depended on codend mesh size as well as configuration (square or diamond). Two of the studies, where square mesh codends had no or a varied effect, also found that size selectivity increased with increases in mesh size for both square and diamond mesh codends. Improved size-selectivity of fishing gear (14 studies): Six of 14 replicated, controlled studies (including three paired, one randomized and one randomized and paired) in the Atlantic Ocean, Mediterranean Sea, Adriatic Sea, Aegean Sea, English Channel, Pacific Ocean, Tasman Sea and the Kattegat and Skagerrak, found that using a square mesh codend in a trawl net (bottom and pelagic) improved size selectivity for silver hake, horse mackerel, European hake, axillary seabream, poor cod, greater forkbeard, blue whiting, discarded fish and three of four commercially targeted fish, compared to diamond mesh codends. Five studies found no difference in size selectivity between square and diamond mesh codends for Atlantic mackerel, long rough dab, yellowtail scad and striped seapike, rockfish and flatfish, and three of four commercially important bottom fish species. The other three studies found that the effect of square mesh instead of diamond mesh codends varied with fish body shape (round or flat), and for three of three and five of five roundfish species size selectivity was improved, but not for one flatfish. Two of the studies, where square mesh codends had either no or a varied effect, also found that size selectivity increased with increases in mesh size for both square and diamond mesh codends. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2714https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2714Fri, 01 Jan 2021 14:39:22 +0000Collected Evidence: Collected Evidence: Fit mesh escape panels/windows to a trawl net Thirty-eight studies examined the effects of fitting one or more mesh escape panels/windows to trawl nets on marine fish populations. Ten studies were in the North Sea (UK, Netherlands, Norway), four studies were in each of the Baltic Sea (Denmark, Sweden, Northern Europe), Kattegat and/or Skagerrak (Norway/Sweden/Denmark) and the Northeast Atlantic Ocean (Iceland, UK, Northern Europe). Two studies were in the Gulf of Carpentaria (Australia) and two were in the Bay of Biscay (France). One study was in each of the Irish Sea (UK), the Tasman Sea (Australia), the Bering Sea (USA), the Indian Ocean (Mozambique), the Norwegian Sea (Norway), the Pacific Ocean (Chile), the Mid-Atlantic Bight (USA), the Gulf of Maine (USA) and the Tyrrhenian Sea (Italy). Two studies were reviews (Northern Europe), and one study was in a laboratory (Japan).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, controlled study in the Baltic Sea found that there was no difference in survival between cod escaping from diamond mesh codends with or without square mesh escape windows. BEHAVIOUR (1 STUDY) Use (1 study): One replicated study in a laboratory found that small immature masu salmon were able to actively swim (escape) through the meshes of square mesh panels under simulated trawl conditions. OTHER (36 studies) Reduce unwanted catch (30 studies): One before-and-after study in the Baltic Sea and fourteen of 19 replicated studies (including one paired, four controlled, 10 paired and controlled, and one randomized, paired and controlled) in the North Sea, Kattegat and Skagerrak, Irish Sea, Tasman Sea, Bering Sea, Gulf of Carpentaria, Mid-Atlantic Bight, Indian Ocean, Baltic Sea, Northeast Atlantic Ocean, Bay of Biscay, Tyrrhenian Sea and the Pacific Ocean, found that square mesh escape panels/windows of varying designs and number fitted to diamond mesh trawl nets (bottom and pelagic), reduced the unwanted catches (non-target or non-marketable species/sizes) of all fish species monitored, all but one and one of four fish species, the main unwanted fish species but only two of nine other finfish, and the total unwanted/discarded catch (fish and invertebrates combined), compared to standard diamond mesh trawl nets, and the effect varied with panel/window design, position in the net and/or fish body type, as well as catch size. The other five studies and a review study of mesh escape panel/window use in the Kattegat and Skagerrak, found that square mesh panels/windows did not reduce the unwanted catches of fish, Atlantic cod and three of three commercial bottom fish species, compared to diamond mesh nets without panels/windows. Four of five replicated, controlled studies (including three paired) in the North Sea, Northeast Atlantic Ocean and Gulf of Maine, found that large diamond mesh escape panels in diamond mesh trawl nets (beam and bottom) reduced unwanted catches of cod, whiting and haddock, and discarded catch (fish and invertebrates), but not of whiting in one study, compared to nets without large diamond mesh panels, and the effect varied with panel design and vessel size. The other study found that the unwanted catches of only one of seven species/groups of non-target fish was reduced by a large diamond mesh panel. Two replicated, paired, controlled studies in the North Sea and Baltic Sea found that new or different configurations of square mesh panels/windows in diamond mesh trawl nets reduced unwanted fish and cod catches, compared to existing/standard panels or windows. One replicated, paired, controlled study in the Gulf of Carpentaria found that diamond mesh trawl nets with either a top square mesh escape panel or a large supported opening ('Bigeye') reduced unwanted shark, but not ray and sawfish catches compared to standard trawl nets. One before-and-after study in the Bay of Biscay found that supplementing a top square mesh escape window in a prawn trawl net with either a bottom window, a flexible escape grid or an increased mesh size diamond codend, did not reduce the unwanted hake catch Improved size selectivity of fishing gear (9 studies): One review study of mesh escape panel/window use in the Kattegat and Skagerrak and four of six replicated, controlled studies (including four paired) in the Baltic Sea, North Sea, northeast Atlantic Ocean, found that square mesh escape panels/windows in diamond mesh trawl nets improved the size selectivity of trawl nets for Atlantic cod and haddock, compared to trawl nets without panels/windows, and there was no difference compared to standard trawl nets with reduced mesh circumferences, and the effect varied with panel position and design. The other two studies found no effect on the size selectivity of undersized fish, haddock, saithe or Atlantic cod, compared to standard trawl nets. One review study of gear size selectivity in the northeast Atlantic Ocean found that the effect of fitting square mesh panels to trawl nets on haddock selectivity varied with panel mesh size, position, and time of year. One replicated, controlled study in the Norwegian Sea found no difference in the size selectivity of cod and haddock between diamond mesh trawl nets fitted with either square mesh escape windows, rigid size-sorting escape grids or a large diamond mesh codend. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2716https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2716Sat, 02 Jan 2021 12:18:36 +0000Collected Evidence: Collected Evidence: Modify the configuration of a mesh escape panel/window in a trawl net Ten studies examined the effects of modifying the configuration (position/size and increased mesh size) of a mesh escape panel/window in a trawl net on marine fish populations. Four studies were in the Baltic Sea (Sweden/Poland). Two studies were in each of the North Sea (UK), the Irish Sea (UK) and the Kattegat and Skagerrak (Northern Europe). One study was in the Atlantic Ocean (Portugal).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, controlled study in the Baltic Sea found that modifying the position of a mesh escape panel in a trawl net had no effect on the survival rate of cod. BEHAVIOUR (0 STUDIES) OTHER (9 STUDIES) Reduction of unwanted catch (5 studies): Three of five replicated, paired studies (one controlled) in the Irish Sea, Atlantic Ocean and Kattegat-Skagerrak found that modifying the position or mesh size of a mesh escape panel/window in a trawl net reduced the unwanted catches of whiting in one of two cases, haddock and whiting, and boarfish, but caught similar amounts of horse mackerel and blue whiting. The other studies found that catches of unwanted cod or other fish were not reduced. Improved size-selectivity of fishing gear (4 studies): Two of four replicated, controlled studies in the North Sea and Baltic Sea found that modifying the position and/or size of a mesh escape panel in a trawl net improved size-selectivity of haddock and whiting. One of these studies also found that increasing the mesh size of the panel had no effect on size-selectivity for haddock. The other two studies found that size-selectivity was similar for cod compared to standard trawls. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2717https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2717Tue, 05 Jan 2021 14:46:39 +0000Collected Evidence: Collected Evidence: Fit a size-sorting escape grid (rigid or flexible) to a fish trawl net Eighteen studies examined the effects of fitting size-sorting escape grids to a fish trawl net on marine fish populations. Six studies were in the North Sea (France, Norway, Scotland), three were in the North Atlantic Ocean (Portugal, USA), and two were in the Norwegian Sea (Norway). One study was in each of the Barents Sea (Norway), the South Atlantic Ocean (Namibia), the Mediterranean Sea (Spain), the Adriatic Sea (Italy), the Gulf of Maine (USA), and the Baltic Sea (northern Europe). One study was in a laboratory (Japan).  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. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2720https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2720Fri, 08 Jan 2021 16:54:19 +0000Collected Evidence: Collected Evidence: Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net Thirty studies examined the effects of fitting size-sorting escape grids to prawn/shrimp trawl nets on marine fish populations. Five studies were in the North Sea (Scotland/Norway, Belgium/Netherlands, UK, Scotland), four were in the Coral Sea (Australia) and two were in each of the Gulf of Carpentaria (Australia), the Indian Ocean (Australia, Mozambique), the North Atlantic Ocean (Portugal, USA), the Pacific Ocean (Chile, USA), the Skagerrak and Kattegat (northern Europe) and the South Atlantic Ocean (Brazil). One study was in each of the Tasman Sea (Australia), the Greenland Sea (Svalbard), the Bay of Biscay (France), the Gulf of Maine (USA), the Gulf of Thailand (Vietnam), the Tyrrhenian Sea (Italy), the Gulf of St Vincent (Australia), the Persian Gulf (Iran) and the Northeast Atlantic Ocean (Norway). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (30 STUDIES) Reduction of unwanted catch (30 studies): Seven of seven replicated studies (including one controlled) in the northeast Atlantic Ocean, North Sea, North Atlantic Ocean, Greenland Sea, Gulf of Thailand, Tyrrhenian Sea and the Skagerrak and Kattegat found that fitting rigid or flexible size-sorting escape grids, of various types and configurations, to prawn/shrimp trawl nets reduced unwanted fish catches (non-commercial species and discarded commercial species/sizes) by allowing the escape of unwanted sharks and the other fish species monitored. Two of two before-and-after studies in the Gulf of Maine and Pacific Ocean found that after the introduction of size-sorting escape grids to trawl nets in fisheries for shrimp, the capture of non-target and unwanted fish was reduced compared to before grids were used. Eleven of 20 replicated studies (including one controlled and 19 paired and controlled) in the Tasman Sea, Coral Sea, Gulf of Carpentaria, North Sea, Indian Ocean, Bay of Biscay, Skagerrak and Kattegat, Pacific Ocean, South Atlantic Ocean, Gulf of St Vincent and Persian Gulf found that prawn/shrimp trawls with size-sorting escape grids, of various types and configurations, had lower catches of all or all but one undersized or otherwise unwanted fish and shark/ray species monitored, and unwanted total catch (fish and invertebrates), compared to trawl nets without escape grids. Two found that escape grids reduced non-target catches of most sizes of whiting and plaice and larger sizes of total fish, but increased the retention of small cod and haddock. Three studies found a variable effect of fitting escape grids to shrimp/prawn trawl nets on unwanted fish catch compared to nets with no grids, and the effect varied with year, site and grid type. Three found that grids had no effect on the reduction of unwanted fish and catches were similar for all or most of the unwanted non-commercial and commercial fish species/groups and for the total unwanted catch (fish and invertebrates). The other study found that fewer unwanted fish of 10 of 11 species/groups were retained in a shrimp/prawn trawl net with an escape grid used in combination with a diamond mesh codend with the mesh orientation turned by 90°, compared to a conventional diamond mesh net with no grid. One replicated, randomized study in the North Atlantic Ocean found that the reduction in catch of unwanted sharks depended on the type of escape grid and shrimp/prawn trawl net used. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2721https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2721Mon, 18 Jan 2021 16:42:48 +0000Collected Evidence: Collected Evidence: Fit large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets Eight studies examined the effects of fitting large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets on marine fish populations. Three studies were in the northwest Atlantic Ocean (USA) and three were in the Gulf of Carpentaria (Australia). One study was in the north Pacific Ocean (USA) and one was in the Coral Sea (Australia).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (8 STUDIES) Reduction of unwanted catch (8 studies): Six of seven replicated studies (five paired and controlled, and one randomized, paired and controlled) in the Atlantic Ocean, Gulf of Carpentaria, Pacific Ocean and the Coral Sea found that fitting large, supported escape openings (various designs including Fisheyes, Bigeyes and radial escape sections) to trawl nets reduced the overall catches of unwanted fish, immature red snapper and total unwanted catch (fish and invertebrates combined) compared to standard nets. The other study found that there were fewer unwanted Chinook salmon in catches with two of two designs of escape openings, but only one of the designs caught fewer widow rockfish. One replicated, paired and controlled study in the Gulf of Carpentaria found that trawl nets fitted with either large escape openings or a square mesh escape panel reduced unwanted shark catch but not unwanted ray or sawfish catches, compared to standard nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2723https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2723Wed, 20 Jan 2021 16:58:00 +0000Collected Evidence: Collected Evidence: Use a different design or configuration of size-sorting escape grid/system in trawl fishing gear (bottom and mid-water) Twenty-three studies examined the effects of using a different design or configuration of size-sorting escape grid/system in trawl fishing gear on marine fish populations. Ten studies were in the Atlantic Ocean (Canada, USA, Brazil, Spain, Norway). Five studies were in the Barents and/or Norwegian Sea (Norway). Two studies were in the Kattegat and Skagerrak (Denmark/Sweden). One study was in each of the Arafura Sea (Australia), the Greenland Sea (Norway), the North Sea (Norway), the North Pacific Ocean (USA) and the Indian Ocean (Australia). One study was in a laboratory (Japan).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) OTHER (23 STUDIES) Reduction of unwanted catch (17 studies): Six of 16 replicated studies (eight paired and controlled, three controlled, one randomized and controlled, and one paired) in the Atlantic Ocean, a laboratory, Arafura Sea, Barents Sea, Kattegat and Skagerrak, Greenland Sea, North Sea, Pacific Ocean and the Indian Ocean, and one controlled study in the Barents Sea found that using a different design or configuration of size-sorting escape grid/system in trawl nets reduced the unwanted (undersized, non-target, discarded) catches of all or most of the fish species assessed, compared to standard or other grid designs/configurations. Four studies found that the effect of using different escape grids on the reduction of unwanted catch varied with fish species, light conditions, and the type of trawl net used. The other six found that, overall, using a different escape grid did not reduce unwanted fish catch. Improve size-selectivity of fishing gear (7 studies): Three of seven replicated studies (three controlled, one paired and controlled) in the Barents/Norwegian Sea, the Atlantic Ocean and the Greenland Sea found that different types or configurations of size-sorting escape grid systems in trawl nets resulted in better size-selectivity for unwanted redfish and Greenland halibut and of commercial target hake compared to other designs or configurations. Three studies found that the effect of using a different design or configuration of size-sorting escape grid/system on improving the size-selectivity of trawls varied between fish species compared to standard or other escape grid designs. The other study found that a new design of grid system did not improve the size-selectivity of unwanted redfish compared to an existing system. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2728https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2728Mon, 25 Jan 2021 16:30:19 +0000Collected Evidence: Collected Evidence: Use an alternative commercial fishing method Nine studies examined the effects of using an alternative commercial fishing method on marine fish populations. One study was in each of the Arafura Sea (Australia), the Greenland and Norwegian Seas (Norway), the Norwegian Sea (Norway), the Atlantic Ocean (Portugal), the Mediterranean Sea (Italy), the Gulf of Maine (USA), the Coral Sea (Australia), the Tyrrhenian Sea (Italy) and the Kattegat and Skagerrak (Sweden).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (9 STUDIES) Reduction of unwanted catch (9 studies): Seven of nine replicated studies (two controlled, one randomized, controlled, one paired, controlled) in the Arafura Sea, Greenland/Norwegian Sea, Norwegian Sea, Atlantic Ocean, Mediterranean Sea, Gulf of Maine, Coral Sea, Tyrrhenian Sea and Kattegat and Skagerrak found that using an alternative method of fishing caught fewer discarded fish species and reduced the catches of unwanted (discarded or non-commercial species) fish overall, and of immature halibut, haddock, Atlantic cod, bluefin tuna and over half of the individual fish species. One study found that an alternative fishing method caught larger (and more likely to be mature) unwanted hammerhead sharks. The other study found that sizes of striped sea bream, annular sea bream and red mullet were similar in catches between gear types. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2730https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2730Wed, 27 Jan 2021 17:06:17 +0000Collected Evidence: Collected Evidence: Introduce an overall catch limit (quota cap or total allowable catch) by fishery or fleet Nine studies examined the effects of introducing overall catch limits by fishery or fleet on marine fish populations. Three studies were worldwide, two studies were in the South Atlantic Ocean (Namibia/South Africa), two studies were in the North Sea (Northern Europe), and one study was in each of the North Sea and Atlantic Ocean (Scotland) and the North Atlantic Ocean (Canada).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (6 STUDIES) Abundance (5 studies): Four before-and-after studies (two replicated) in the South Atlantic Ocean, the North Atlantic Ocean and the North Sea reported that following the introduction of overall catch limits for fish there was a higher abundance or biomass of hakes, Atlantic herring and Atlantic halibut, compared to before. One replicated, controlled study of fish stocks worldwide found that overfished stocks of tunas and billfishes had faster increases of biomass when managed using overall catch limits, compared to stocks with other types of control or no management. Reproductive success (1 study): A global review reported that after overall catch limits and minimum landing size were introduced there was strong recruitment of broadbill swordfish for one key stock, while recruitment for four other stocks could not be assessed due to limited data. Survival (2 studies): One before-and-after study and one replicated, controlled study in the North Atlantic Ocean and worldwide found that for fish species with overall catch limits there was a decrease or lower fishing mortality, compared either to before implementation or to stocks without catch limits and those with other controls. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Reduction of unwanted catch (1 study): One replicated, before-and-after study in the North Sea and North Atlantic Ocean found that overall catch limits did not reduce unwanted megrim catch despite a reduction in discards, however this was due to retention of more small but legal-sized megrim, previously discarded. Reduction of fishing effort (1 study): One replicated, before-and-after study in the North Sea found that when annual total allowable catch limits were changed (increased or decreased), half of the otter trawl fleet had corresponding changes in fishing effort (increased or decreased), but there were no changes for the beam trawl fleet. Stock status (1 study): One global systematic review found that in terms of reaching biomass-based management targets fisheries with fleet-wide catch quotas were no different to fisheries managed either by catch shares or effort controls. However, along with catch share fisheries, fewer catch quota stocks were over-exploited than those with effort controls. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3811https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3811Thu, 26 May 2022 15:07:14 +0100
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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