Collected Evidence: Collected Evidence: Set longlines at night to reduce seabird bycatch Six out of eight studies from fisheries around the world found lower rates of seabird bycatch on longlines set at night, compared with during the day, or with previously collected data. However, effects seemed to depend on the species caught. Two studies found higher rates of bycatch on night-set longlines, due to high numbers of white-chinned petrels Procellaria aequinoctialis or northern fulmars Fulmarus glacialis being caught at night.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F283https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F283Tue, 24 Jul 2012 13:04:04 +0100Collected Evidence: Collected Evidence: Use streamer lines to reduce seabird bycatch on longlines A total of eight studies and two literature reviews from coastal and pelagic fisheries across the world found strong evidence for reduced seabird bycatch on longlines when streamer lines were used. A replicated, controlled trial from the sub-Antarctic Indian Ocean found no reduction in bycatch rates when using streamer lines, whilst five studies were inconclusive, uncontrolled or had weak evidence for reductions. The effect of streamer lines appears to vary between seabird species: northern fulmars Fulmarus glacialis were consistently caught at lower rates when streamers were used but shearwaters Puffinus spp. and white-chinned petrels Procellaria aequinoctialis were caught at similar rates with and without streamers in one study each. The three studies that investigated the use of multiple streamer lines all found that fewer birds were caught when two streamer lines were used, compared to one, with even fewer caught when three were used.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F285https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F285Tue, 24 Jul 2012 14:37:19 +0100Collected Evidence: Collected Evidence: Set lines underwater to reduce seabird bycatch Four replicated and controlled studies and a literature review in Norway, South Africa and the North Pacific found reductions in northern fulmar Fulmarus glacialis, albatross and petrel bycatch rates when using an underwater setting funnel. Although one found a disproportionate number of albatross were caught during day line setting. A replicated and controlled study found that underwater setting increased attack rates of shearwaters Puffinus spp. on longlines and did not reduce bycatch.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F288https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F288Tue, 24 Jul 2012 16:38:44 +0100Collected Evidence: Collected Evidence: Use a line shooter to reduce seabird bycatch A randomised, replicated and controlled trial from a pelagic fishery in the North Pacific found significantly higher seabird bycatch when a line shooter was used to set longlines. A second randomised, replicated and controlled trial (from Norway), found no effect of a line shooter on bycatch rates.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F290https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F290Tue, 24 Jul 2012 16:47:45 +0100Collected Evidence: Collected Evidence: Weight baits or lines to reduce longline bycatch of seabirds Three replicated and controlled studies found evidence for reduced bycatch in some species when using weighted lines. One study found low bycatch rates, but was uncontrolled. In Hawaii and New Zealand, rates of bait loss and bycatch of albatrosses Phoebastria spp., white-chinned petrels Procellaria aequinoctialis and sooty shearwaters Puffinus griseus were much lower with weighted baits or integrated weight lines than with control lines. In the North Pacific, two trials found that bycatch rates of some species was reduced when using weights, but that shearwaters Puffinus spp. attacked weighted lines more often. A study off New Zealand found that attaching weights to lines had only localised effects on sink-rate.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F296https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F296Tue, 24 Jul 2012 17:07:29 +0100Collected Evidence: Collected Evidence: Use shark liver oil to reduce seabird bycatch Two replicated and controlled trials found reductions in the number of seabirds following boats, or diving for baits, when shark liver oil was dripped behind the boats. Other oils had no effect. A third replicated and controlled trial in found no differences in the number of seabirds following a bait-laying boat with shark liver oil.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F297https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F297Tue, 24 Jul 2012 17:16:47 +0100Collected Evidence: Collected Evidence: Reduce seabird bycatch by releasing offal overboard when setting longlinesTwo replicated and controlled studies in the South Atlantic and sub-Antarctic Indian Ocean found significant reductions in the number of albatross and petrels attacking baits and being caught when offal was released overboard during line setting.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F299https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F299Tue, 24 Jul 2012 17:39:55 +0100Collected Evidence: Collected Evidence: Fit one or more mesh escape panels/windows to trawl nets Seven studies examined the effects of adding one or more mesh escape panels/windows to trawl nets on subtidal benthic invertebrate populations. Six were in the North Sea (Belgium, Netherlands, UK), two in the Thames estuary (UK), one in the English Channel (UK), and one in the Gulf of Carpentaria (Australia).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (7 STUDIES) Overall survival (1 study): One replicated, paired, controlled study in the English Channel and the North Sea found that fitting nets with either one of seven designs of square mesh escape panels (varying mesh size and twine type) led to higher survival rates of invertebrates that escaped the nets compared to unmodified nets. Unwanted catch overall abundance (7 studies): Three of seven replicated, paired, controlled studies in the North Sea, the Thames estuary, the English Channel and the Gulf of Carpentaria  found that trawl nets fitted with one or more mesh escape panels/windows/zones reduced the unwanted catch of invertebrates compared to unmodified nets. Two found mixed effects of fitting escape panels on the unwanted catch of invertebrates and fish depending on the panel design. Two found that trawl nets fitted with escape panels  caught similar amounts of unwanted invertebrates and fish compared to unmodified nets. OTHERS (7 STUDIES) Commercially targeted catch abundance (7 studies): Three of seven replicated, paired, controlled studies in the North Sea, the Thames estuary, the English Channel and the Gulf of Carpentaria, found that trawl nets fitted with one or more mesh escape panels/windows/zones caught similar amounts of all or most commercial species to unmodified nets. Three found mixed effects of fitting escape panels on the catch of all or most commercial species depending on the species and/or panel design. One found that trawl nets fitted with escape panels reduced the catch of commercial species compared to unmodified nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2132https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2132Tue, 22 Oct 2019 10:33:29 +0100Collected Evidence: Collected Evidence: Fit one or more soft, semi-rigid, or rigid grids or frames to trawl nets Two studies examined the effects of fitting one or more soft, semi-rigid, or rigid grids or frames to trawl nets on subtidal benthic invertebrate populations. The studies were in the Gulf of Carpentaria and Spencer Gulf (Australia).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Unwanted catch abundance (1 study): Two replicated, paired, controlled studies in the Gulf of Carpentaria and in Spencer Gulf found that nets fitted with a ‘downward’-oriented grid but not an ‘upward’-oriented grid reduced the weight of small unwanted catch and that both grid orientations caught fewer unwanted large sponges, and that nets fitted with two sizes of grids reduced the number and biomass of unwanted blue swimmer crabs and giant cuttlefish caught, compared to unmodified nets. OTHER (2 STUDIES) Commercial catch abundance (2 studies): Two replicated, paired, controlled studies in the Gulf of Carpentaria and Spencer Gulf found that nets fitted with a ‘downward’-oriented grid or a small grid reduced the catch of commercially targeted prawns, compared to unmodified nets, but those fitted with an ‘upward’-oriented grid or a large grid caught similar amounts to unmodified nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2133https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2133Tue, 22 Oct 2019 10:46:29 +0100Collected Evidence: Collected Evidence: Modify the position of traps Two studies examined the effects of modifying the position of traps on subtidal benthic invertebrate populations. One study was in the Varangerfjord (Norway), the other in the North Atlantic Ocean (Spain).   COMMUNITY RESPONSE (1 STUDY) Unwanted catch species richness/diversity (1 study): One replicated, controlled study in the North Atlantic found that semi-floating traps caught fewer unwanted catch species compared to standard bottom traps. POPULATION RESPONSE (2 STUDIES) Unwanted catch abundance (2 studies): Two replicated, controlled studies in the Varangerfjord and the North Atlantic found that floating or semi-floating traps caught fewer unwanted invertebrates compared to standard bottom traps. OTHER (2 STUDIES) Commercial catch abundance (2 studies): Two replicated, controlled studies in the Varangerfjord and the North Atlantic found that floating or semi-floating traps caught similar amounts (abundance and biomass) of commercially targeted species as standard bottom traps. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2144https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2144Tue, 22 Oct 2019 11:14:51 +0100Collected Evidence: Collected Evidence: Set catch limits or quotas for non-targeted commercial catch Two studies examined the effects of setting catch limits or quotas for non-targeted commercial fish species on marine fish populations. One review was in the North Atlantic and Pacific Oceans and one study was in the Pacific Ocean (Canada).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Reduction of unwanted catch (2 studies): One review in the Atlantic and Pacific Oceans found that setting catch limits or quotas for non-commercially targeted fish reduced unwanted catch in two of three cases. One before-and-after study in the Pacific Ocean found that catch limits for non-target commercial species reduced the amount of unwanted halibut, but a previous quota system based on the whole catch (individual transferrable quotas) did not. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2693https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2693Wed, 02 Dec 2020 16:15:52 +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: 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: Establish temporary fishery closures Three studies evaluated the effects of establishing temporary fishery closures on reptile populations. Two studies were in the USA and one was in Brazil. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (1 study): One site comparison study in Brazil found that areas where a fishing agreement was implemented that involved seasonal fishing restrictions along with a wider set of measures had more river turtles than areas that did not implement the agreement.  Survival (2 studies): One replicated, before-and-after study in the USA found that during seasonal closures of shrimp trawling there were fewer lethal strandings of loggerhead and Kemp’s ridley turtles. One study in the USA found that following the re-opening of a swordfish long-line fishery with turtle catch limits in place, loggerhead turtle bycatch reached the annual catch limit in two of three years, and when the limit was reached the fishery was closed for the rest of the year. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3545https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3545Tue, 07 Dec 2021 17:27:09 +0000Collected Evidence: Collected Evidence: Deploy fishing gear at different depths Three studies evaluated the effects of deploying fishing gear at different depths on reptile populations. One study was in each of Canada, off the coast of Mexico and the Atlantic. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, randomized, paired study in Canada found that no turtles died in floated nets, but some died in submerged nets. Condition (1 study): One replicated, randomized, paired study in Canada found that turtles caught in floated nets were less at risk of drowning than those caught in submerged nets. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Unwanted catch (3 studies): Two of three studies (including two replicated studies) in Canada, Mexico and the Atlantic found that bottom-set fishing nets with fewer buoys caught fewer sea turtles than standard nets or that fewer loggerhead turtles were caught when longline hooks were set below 22 m deep, but the number of leatherback turtles caught was unaffected by hook depth. The other study found that floated and submerged nets caught a similar number of turtle species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3547https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3547Wed, 08 Dec 2021 09:29:51 +0000Collected Evidence: Collected Evidence: Add lights to fishing gear Five studies evaluated the effects of adding lights to fishing gear on reptile populations. Two studies were in the Baja California peninsula (Mexico) and one was in each of Sechura Bay (Peru), the Atlantic and North Pacific and the Adriatic Sea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One randomized, controlled, paired study in the Adriatic Sea found that no loggerhead turtles were caught and died in in gillnets with UV lights whereas some did in nets without lights. BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Unwanted catch (5 studies): Four controlled studies (including three replicated and two paired studies) in the Baja California peninsula, Sechura Bay and the Adriatic Sea found that gillnets with LED lights, light sticks or UV lights caught fewer green turtles and loggerhead turtles than nets without lights. One replicated study in the Atlantic and North Pacific found mixed effects of increasing the number of light sticks on longlines on the chance of catching loggerhead and leatherback turtles. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3554https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3554Wed, 08 Dec 2021 13:59:36 +0000Collected Evidence: Collected Evidence: Use circle hooks instead of J-hooks Eleven studies evaluated the effects of using circle hooks instead of J-hooks on reptile populations. Five studies were in the Atlantic, three were in the Pacific and one study was in each of the Mediterranean, the Atlantic and North Pacific and the western North Atlantic, Azores, Gulf of Mexico and Ecuador. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Survival (3 studies): Two studies (including one replicated, controlled, paired study) off the coast of Hawaii and in the north-east Atlantic Ocean found that survival of loggerhead and leatherback turtles and leatherback and hard-shell sea turtles caught by circle hooks or J-hooks was similar. One review of studies in five pelagic longline fisheries found that fewer sea turtles died when circle hooks were used compared to J-hooks in four of five fisheries. Condition (3 studies): Two replicated, controlled studies in the Mediterranean Sea and south-western Atlantic Ocean found that fewer immature loggerhead turtles and loggerhead turtles swallowed circle hooks compared to J-hooks. One before-and-after study off the coast of Hawaii found that a lower percentage of loggerhead and leatherback turtles were deeply hooked by circle hooks compared to J-hooks. BEHAVIOUR (0 STUDIES) OTHER (11 STUDIES) Unwanted catch (11 studies): Seven of 10 studies (including six replicated, controlled studies) in the Pacific, Atlantic, Atlantic and North Pacific and Mediterranean and one review of studies in five pelagic longline fisheries found that circle hooks or circle hooks and tuna hooks caught fewer sea turtles than J-hooks, or that non-offset G-style circle hooks caught fewer leatherback and hard-shell sea turtles that offset J-Hooks. One of these studies also found that circle hooks caught slightly larger loggerhead turtles than J-hooks, and one also found that offset Gt-style circle hooks caught a similar number of leatherback and hard-shell sea turtles compared to offset J-hooks. One study found that circle hooks caught a similar number of leatherback, green and olive ridley turtles compared to J-hooks. One study found that fish-baited circle hooks caught fewer loggerhead and leatherback turtles than squid-baited J-hooks. The review found mixed effects of using circle hooks compared to J-hooks on unwanted catch of sea turtles depending on the fishery. The other study found mixed effects of using circle hooks or J-hooks in combination with squid or fish bait on the number of loggerhead and leatherback turtles that were caught. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3559https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3559Wed, 08 Dec 2021 14:21:43 +0000Collected Evidence: Collected Evidence: Install exclusion devices on fishing gear: Sea turtles Three studies evaluated the effects of installing exclusion devices on fishing gear on sea turtle populations. One study was in the Gulf of Mexico (USA), one was in the Mid-Atlantic (USA) and one was off the coast of Western Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, before-and-after study in the Gulf of Mexico found that when exclusion grids with escape holes were used in a shrimp trawl fishery there were fewer lethal strandings of loggerhead turtles compared to when grids were not used. BEHAVIOUR (1 STUDY) Use (1 study): One controlled study in the Mid-Atlantic found that when exclusion devices were used on scallop dredges there were fewer interactions with sea turtles than when no devices were used. OTHER (1 STUDY) Unwanted catch (1 study): One replicated study off the coast of Western Australia found that exclusion grids with escape hatches prevented sea turtles entering trawl nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3584https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3584Wed, 08 Dec 2021 15:30:20 +0000Collected Evidence: Collected Evidence: Install exclusion devices on fishing gear: Tortoises, terrapins, side-necked & softshell turtles Thirteen studies evaluated the effects of installing exclusion devices on fishing gear on tortoise, terrapin, side-necked & softshell turtle populations. Ten studies were in the USA, two were in Canada and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, randomized, paired, controlled study in the USA found that fewer turtles died in hoop nets with an exclusion device than in unmodified traps. BEHAVIOUR (1 STUDY) Use (1 study): One randomized, controlled trial in the USA found mixed effects of crab pot exclusion devices on use of pots by diamondback terrapins depending on the device design. OTHER (13 STUDIES) Unwanted catch (13 studies): Eight of 13 controlled studies (including seven replicated, paired studies) in the USA, Australia and Canada found that crab pots, fyke nets, hoop nets and eel traps with exclusion devices caught fewer turtles, diamond back terrapins and short-necked turtles than unmodified gear. Two studies also found that modified gear caught smaller short-necked turtles and diamondback terrapins than unmodified gear. Three studies found mixed effects of exclusion devices on unwanted catch of turtles and diamondback terrapins depending on the device design. The other two studies found that that crab pots with wire exclusion devices or magnetized exclusion devices caught a similar number of diamondback terrapins compared to unmodified pots. One study also found that crab pots with wire exclusion devices caught larger diamondback terrapins than pots with plastic exclusion devices. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3590https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3590Wed, 08 Dec 2021 16:11:04 +0000Collected Evidence: Collected Evidence: Install escape devices on fishing gear: Snakes & lizards Three studies evaluated the effects of installing escape devices on fishing gear on snake and lizard populations. All three studies were in the Gulf of Carpentaria (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Unwanted catch (3 Studies): One of two paired, controlled studies (including one randomized and one replicated study) in the Gulf of Carpentaria found that trawl nets with escape devices caught a similar number of sea snakes compared to unmodified nets. The other study found that trawl nets with an escape device caught fewer sea snakes compared to unmodified nets. One replicated, paired, controlled study in the Gulf of Carpentaria found that the placement of escape devices trawl nets affected the number of sea snakes caught compared to unmodified nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3603https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3603Thu, 09 Dec 2021 10:08:51 +0000Collected Evidence: Collected Evidence: Install exclusion and escape devices on fishing gear Six studies evaluated the effects of installing exclusion and escape devices on fishing gear on reptile populations. Two studies each were off the coast of Australia, in the Gulf of Carpentaria (Australia) and in the Adriatic Sea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (2 STUDIES) Use (2 studies): Two replicated studies (including one controlled study) in the Adriatic Sea found that one or two loggerhead turtles were able to escape from a trawl net with an exclusion and escape device. OTHER (5 STUDIES) Unwanted catch (5 studies): Four studies (including two replicated, paired, controlled studies) off the coast of Australia and in the Gulf of Carpentaria (Australia) found that that trawl nets with an exclusion and escape device caught fewer loggerhead turtles or sea turtles and sea snakes compared to unmodified nets. One replicated study in the Adriatic Sea found that no loggerhead turtles were caught by a trawl net with an exclusion and escape device. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3605https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3605Thu, 09 Dec 2021 10:22:38 +0000Collected Evidence: Collected Evidence: Use a different bait type: Sea turtles Nine studies evaluated the effects of using a different bait type on sea turtle populations. Three studies were in each of the Atlantic and Pacific, and one was in each of the Atlantic and north Pacific, the Gulf of Garbes (Tunisia) and Italy. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): Two studies (including one replicated, controlled study) off the coast of Hawaii and in the Southern Atlantic found that the percentage of loggerhead and leatherback turtles that survived being caught by fish-baited or squid-baited hooks or fish-baited circle hooks and squid-baited J-hooks was similar. Condition (1 study): One before-and-after study off the coast of Hawaii found that fish-baited circle hooks deeply hooked fewer leatherback and hard-shell turtles compared to squid-baited J-hooks. BEHAVIOUR (1 STUDY) Use (1 study): One controlled study in Italy found that loggerhead turtles in a captive setting were less likely to bite at fish bait than squid bait. The study also found that smaller turtles were more likely to bite at mackerel bait and larger turtles at squid bait. OTHER (8 STUDIES) Unwanted catch (8 studies): Four of five studies (including one replicated, paired, controlled study) in the North Pacific, Eastern Pacific, Atlantic and Atlantic and North Pacific found that fish-baited hooks caught fewer sea turtles or were swallowed by fewer olive ridley turtles than squid baited hooks. One study also found that fish bait in combination with larger circle hooks lead to the highest percentage of external hookings. The other study found mixed effects of using fish or squid-baited hooks on the unwanted catch of hard-shell and leatherback turtles. One replicated, controlled study in the north-western Atlantic Ocean found that fish-baited J-hooks caught fewer sea turtles compared to squid-baited hooks. The study also found that unwanted catch was more similar for fish-baited and squid-baited circle hooks. One before-and-after study off the coast of Hawaii found that fish-baited circle hooks caught fewer loggerhead and leatherback turtles compared to compared to squid-baited J-hooks. One replicated study in the Gulf of Garbes found that hooks baited with stingray caught fewer loggerhead turtles compared to fish-baited hooks. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3612https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3612Thu, 09 Dec 2021 12:02:07 +0000Collected Evidence: Collected Evidence: Release accidentally caught (‘bycatch’) reptiles Three studies evaluated the effects on reptile populations of releasing accidentally caught reptiles. One study was in each of the Caribbean Sea, Costa Rica and the Republic of Korea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One replicated study in the Caribbean Sea found that from a released group of green turtles that included some accidentally caught and some head-started individuals, some survived for at least several months in the wild. One replicated study in the Republic of Korea found that green turtles caught in pound nets all survived for at least two weeks to a year after release. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One controlled study off the Pacific coast of Costa Rica found that the behaviour of longline-caught sea turtles following release was broadly similar to free-swimming turtles. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624Thu, 09 Dec 2021 13:37:44 +0000
What Works 2021 cover

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.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust
For a full list of, and information about, our champions:
All Evidence Champions
About our champions, why and how to become one:
Become an Evidence Champion

This website uses Cookies

We use limited Cookies to run the site and to analyse our traffic (none for site vendors). By using this site, you will be providing your consent to our use of Cookies.

Accept & continue