Collected Evidence: Collected Evidence: Use an alternative method to commercially harvest plankton One study examined the effect of using an alternative method to commercially harvest plankton on marine fish populations. The study was in the Norwegian Sea (Norway).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction of unwanted catch (1 study): One controlled study in the Norwegian Sea found that the amount of unwanted fish larvae and eggs in fine-mesh catches of zooplankton were reduced after deployment of a bubble-plume harvester, compared to without deployment. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2731https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2731Thu, 28 Jan 2021 11:41:59 +0000Collected Evidence: Collected Evidence: Replace or repair damaged anti-predator nets around aquaculture systems One study evaluated the effects on marine mammals of replacing anti-predator nets around aquaculture systems. The study was in the North Atlantic Ocean (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES)       OTHER (1 STUDY) Human-wildlife conflict (1 study): One site comparison study in the North Atlantic Ocean found that replacing anti-predator nets more frequently at salmon farms resulted in fewer salmon losses to harbour seal predation. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2774https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2774Thu, 04 Feb 2021 15:21:20 +0000Collected Evidence: Collected Evidence: Establish ‘move-on rules’ for fishing vessels if mammals are encountered One study evaluated the effects on marine mammals of establishing move-on rules for fishing vessels if mammals are encountered. The study was in the Great Australian Bight (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One before-and-after study in the Great Australian Bight found that introducing measures to delay or relocate fishing if dolphins were encountered, along with releasing trapped dolphins, resulted in fewer short-beaked common dolphins being encircled and killed. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2790https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2790Thu, 04 Feb 2021 16:29:13 +0000Collected Evidence: Collected Evidence: Deploy fishing gear at different depths One study evaluated the effects on marine mammals of deploying fishing gear at different depths. The study was in the Arafura Sea (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction in entanglements/unwanted catch (1 study): One controlled study in the Arafura Sea found that fishing nets deployed 4.5 m below the water surface had fewer entanglements of dolphins than surface nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2793https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2793Thu, 04 Feb 2021 16:33:47 +0000Collected Evidence: Collected Evidence: Use stiffened materials or increase tension of fishing gear One study evaluated the effects on marine mammals of using stiffened materials in fishing nets. The study was in the South Atlantic Ocean (Argentina). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction in entanglements/unwanted catch (1 study): One controlled study in the South Atlantic Ocean found that using stiffened fishing nets did not reduce the number of Franciscana dolphin entanglements. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2801https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2801Thu, 04 Feb 2021 17:10:46 +0000Collected Evidence: Collected Evidence: Play predator calls to deter mammals from fishing gear One study evaluated the effects of playing predator calls to deter mammals from fishing gear. The study was in the South Atlantic Ocean (Africa). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): One study in the South Atlantic Ocean found that playing killer whale vocalisations did not deter Cape fur seals from feeding on fish catches in a purse-seine net or trawl net. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2817https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2817Fri, 05 Feb 2021 15:08:39 +0000Collected Evidence: Collected Evidence: Use noise aversive conditioning to deter mammals from fishing gear One study evaluated the effects on marine mammals of using noise aversive conditioning to deter mammals from fishing gear. The study was in the North Pacific Ocean (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): One study in the North Pacific Ocean found that noise aversive conditioning did not reduce bait foraging behaviour by California sea lions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2819https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2819Fri, 05 Feb 2021 15:12:55 +0000Collected Evidence: Collected Evidence: Use acoustic decoys to divert mammals away from fishing gear One study evaluated the effects on marine mammals of using acoustic decoys to divert mammals away from fishing gear. The study was in the Gulf of Alaska (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Behaviour change (1 study): One study in the Gulf of Alaska found that increasing the distance between an acoustic decoy device and fishing lines resulted in fewer sperm whales at the lines, but sperm whale presence and time of arrival did not differ. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2820https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2820Fri, 05 Feb 2021 15:15:05 +0000Collected Evidence: Collected Evidence: Use ‘mammal-safe’ nets to capture and release mammals trapped in fishing structures One study evaluated the effects on marine mammals of using ‘mammal-safe’ nets to capture and release mammals trapped in fishing structures. The study was in the Bay of Fundy (Canada). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One controlled study in the Bay of Fundy found that using ‘marine mammal nets’ with a larger mesh size to release harbour porpoises from herring weirs resulted in lower porpoise mortality compared to using conventional herring nets. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2828https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2828Fri, 05 Feb 2021 16:00:21 +0000Collected Evidence: Collected Evidence: Establish handling and release protocols for mammals captured by fisheries One study evaluated the effects on marine mammals of establishing handling and release protocols for mammals captured by wild fisheries. The study was in the Great Australian Bight (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One before-and-after study in the Great Australian Bight found that introducing a code of conduct for releasing dolphins trapped in nets, along with avoiding dolphins during fishing, resulted in lower mortality of short-beaked common dolphins. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2829https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2829Fri, 05 Feb 2021 16:02:48 +0000Collected Evidence: Collected Evidence: Restore habitat for marine and freshwater mammals One study evaluated the effects of restoring habitat for marine mammals. The study was in the Kattegat sea (Denmark). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One before-and-after study in the Kattegat sea found that harbour porpoise activity increased at a stony reef after it was restored with boulders and fishing was prohibited. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2920https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2920Mon, 08 Feb 2021 16:36:03 +0000Collected Evidence: Collected Evidence: Set unwanted catch quotas One study evaluated the effects of setting unwanted catch quotas on reptile populations. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): 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%2F3549https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3549Wed, 08 Dec 2021 12:07:09 +0000Collected Evidence: Collected Evidence: Promote knowledge exchange between fishers to improve good practice One study evaluated the effects on reptile populations of promoting knowledge exchange between fishers to improve good practice. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One before-and-after study in the USA found that following the introduction of a tool to help facilitate knowledge exchange and the avoidance of loggerhead turtles, loggerhead turtle bycatch was similar compared to the two years before the tool was introduced. BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human behaviour change (1 study): One before-and-after study in the USA found that following the introduction of a tool to help facilitate avoidance of loggerhead turtles, fishers did not spend less time fishing in the areas recommended for avoidance by the tool.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3558https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3558Wed, 08 Dec 2021 14:13:04 +0000Collected Evidence: Collected Evidence: Use non-ringed hooks One study evaluated the effects of using non-ringed hooks on reptile populations. This study was in the Mediterranean. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Unwanted catch (1 study): One replicated, paired study in the Mediterranean found that when non-ringed circle hooks were used in a swordfish longline fishery fewer loggerhead turtles were caught compared to when ringed hooks were used. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3576https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3576Wed, 08 Dec 2021 15:18:56 +0000Collected Evidence: Collected Evidence: Modify number of hooks between floats on longlines One study evaluated the effects of modifying the number of hooks between floats on longlines on reptile populations. This study was in the Atlantic and North Pacific. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Unwanted catch (1 study): One replicated study in the Atlantic and North Pacific found that having fewer hooks between floats did not reduce turtle by-catch in the Pacific but had mixed effects in the Atlantic depending on the species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3580https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3580Wed, 08 Dec 2021 15:25:39 +0000Collected Evidence: Collected Evidence: Install exclusion devices on fishing gear: Snakes & lizards One study evaluated the effects of installing exclusion devices on fishing gear on snake and lizard populations. This study was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Unwanted catch (1 study): One replicated study off the coast of Western Australia found that exclusion grids did not prevent sea snakes from entering trawl nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3599https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3599Wed, 08 Dec 2021 16:47:50 +0000Collected Evidence: Collected Evidence: Install escape devices on fishing gear: Sea turtles One study evaluated the effects of installing escape devices on fishing gear on sea turtle populations. This study was in the Gulf of Carpentaria (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Unwanted catch (1 Study): One randomized, paired, controlled study in the Gulf of Carpentaria found that trawl nets with escape devices caught a similar number of sea turtles compared to unmodified nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3601https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3601Wed, 08 Dec 2021 17:09:33 +0000Collected Evidence: Collected Evidence: Limit the number of fishing days One study examined the effects of limiting the number of fishing days on marine fish populations. The study was in the Mediterranean Sea (Italy). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One before-and-after study in the Mediterranean Sea reported that in the 10 years following a decrease in overall number of days fished by a bottom trawl fleet, there was a higher biomass of thornback and brown rays. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3804https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3804Thu, 26 May 2022 14:24:22 +0100Collected Evidence: Collected Evidence: Limit fishing activity by vessel size and/or engine power One study examined the effects of limiting fishing activity by vessel size and/or engine power on marine fish populations. The study was in the North Sea (Northern Europe).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One before-and-after study in the North Sea found that after vessels with a higher engine power were excluded from an area for half of each year there was a higher abundance of commercially targeted fish, but no difference in the overall abundance of non-commercially targeted fish over five years. In addition, for all fish, abundance was higher for two of eight size-groups. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3809https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3809Thu, 26 May 2022 14:53:03 +0100Collected Evidence: Collected Evidence: Set catch shares by species One study examined the effects of setting catch shares by species on marine fish populations. The study was in the Pacific Ocean (Canada).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction of unwanted catch (1 study): One before-and-after study in the Pacific Ocean found that after a species-specific catch share was set (Individual Vessel Bycatch Quota) unwanted halibut catch in a multi-species fishery was reduced, whereas it was higher under a previous catch share system (Individual Transferable Quota) based on all species in the catch. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3814https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3814Fri, 27 May 2022 08:31:55 +0100Collected Evidence: Collected Evidence: Prohibit high grading in which only the most profitable individuals or species are landed One study examined the effects of prohibiting high grading in which only the most profitable individuals or species are landed on marine fish populations. The study was in the North Sea/North Atlantic Ocean (UK).   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Commercial catch abundance/landings (1 study): One replicated, before-and-after study in the North Sea/North Atlantic Ocean reported that a ban on high grading did not eliminate the discarding of legal-sized but unwanted common megrim Lepidorhombus whiffiagonis that were required to be landed. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3823https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3823Fri, 27 May 2022 08:55:44 +0100Collected Evidence: Collected Evidence: Use technology to communicate near real-time catch information to fishers to enable avoidance of unwanted catchicate near real-time catch information to fishers to enable avoidance of unwanted catch One study examined the effects of using technology to communicate near real-time catch information to fishers to enable avoidance of unwanted catch on marine fish populations. The study was in the North Pacific and North Atlantic Oceans.   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction of unwanted catch (1 study): A review in the North Pacific and North Atlantic Oceans reported that where technology was used to provide near real-time catch information to fishers there were reductions of unwanted catch or discards in two of three cases. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3826https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3826Fri, 27 May 2022 09:38:00 +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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