Collected Evidence: Collected Evidence: Use acoustic devices at aquaculture systems Six studies evaluated the effects on marine and freshwater mammals of using acoustic devices at aquaculture systems. Four studies were in the North Atlantic Ocean (USA, UK), one was in the Reloncaví fjord (Chile) and one in the Mediterranean Sea (Italy). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (6 STUDIES) Human-wildlife conflict (6 studies): Four of six studies (including five before-and-after and/or site comparison studies and one controlled study) in the North Atlantic Ocean, the Reloncaví fjord and the Mediterranean Sea found that using acoustic devices at salmon farms reduced predation on caged salmon by grey seals, harbour seals and South American sea lions, or reduced the number of harbour seals approaching a fish cage. The two other studies found that using acoustic devices did not reduce harbour seal predation at salmon farms, or reduce the presence, approach distances, groups sizes or time spent around fin-fish farms by common bottlenose dolphins. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2775https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2775Thu, 04 Feb 2021 15:29:04 +0000Collected Evidence: Collected Evidence: Translocate mammals away from aquaculture systems to reduce human-wildlife conflict Two studies evaluated the effects of translocating mammals away from aquaculture systems to reduce human-wildlife conflict. Both studies were in the Tasman Sea and one was also in the Southern Ocean (Tasmania). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES)       OTHER (2 STUDIES) Human-wildlife conflict (2 studies): Two studies (including one site comparison study) in the Tasman Sea (one also in the Southern Ocean) found that more than half or nearly all of Australian and New Zealand fur seals translocated away from salmon farms returned. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2776https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2776Thu, 04 Feb 2021 15:43:44 +0000Collected Evidence: Collected Evidence: Set and enforce vessel speed limits Two studies evaluated the effects on marine and freshwater mammals of setting and enforcing vessel speed limits. One study was in the Indian River estuarine system (USA) and the other in the North Atlantic Ocean (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One before-and-after study in the Indian River estuarine system found similar numbers of manatee deaths before and after vessel speed limits were set in ‘zones’, but fewer deaths were recorded after speed limits were set and enforced in all areas. One before-and-after study in the North Atlantic Ocean found that setting vessel speed limits during specific periods in key habitats resulted in fewer North Atlantic right whale deaths caused by collisions. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2777https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2777Thu, 04 Feb 2021 15:48:43 +0000Collected Evidence: Collected Evidence: Prohibit or restrict hunting of marine and freshwater mammal species Five studies evaluated the effects of prohibiting hunting of marine mammal species. One study was in each of the Kattegat and Skagerrak seas (Denmark and Sweden), the North Atlantic Ocean, North Pacific Ocean and the Southern Hemisphere, the South Pacific Ocean (Australia), the North Atlantic Ocean (Greenland) and the Southern Ocean (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Abundance (5 studies): Four of five studies (including three before-and-after studies) in the Kattegat and Skagerrak Seas, the South Pacific Ocean, the North Atlantic Ocean and the Southern Ocean found that after hunting was prohibited, the abundance of harbour seals and humpback whales increased over 7–30 years. The other study found that numbers of mature male sperm whales did not differ significantly before or 31 years after hunting was prohibited. One review in the North Atlantic Ocean, North Pacific Ocean and the Southern Hemisphere found significant increase rates for 10 of 12 baleen whale populations during 7–21 years after legislation to prohibit hunting was introduced. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2780https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2780Thu, 04 Feb 2021 16:09:52 +0000Collected Evidence: Collected Evidence: Increase visual detectability of fishing gear for mammals Two studies evaluated the effects on marine mammals of increasing the visual detectability of fishing gear for mammals. One study was in the Gulf of St. Lawrence (Canada) and one was in Cape Cod Bay (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (2 STUDIES) Behaviour change (2 studies): One study in the Gulf of St. Lawrence found that minke whales approached white ropes more slowly and changed their bearing more when approaching black ropes compared to ropes of other colours. One study in Cape Cod Bay found that simulated ropes painted red or orange were detected by North Atlantic right whales at greater distances than green but not black ropes, and more whales collided with green ropes than the other three rope colours. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2805https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2805Thu, 04 Feb 2021 17:16:45 +0000Collected Evidence: Collected Evidence: Attach acoustically reflective objects to fishing gear Two studies evaluated the effects on marine mammals of attaching acoustically reflective objects to fishing gear. One study was in the Timor Sea and Arafura Sea (Australia) and one was in the Gulf of Alaska (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Reduction in entanglements/unwanted catch (1 study): One controlled study in the Timor Sea and Arafura Sea found that attaching metallic bead chains to fishing nets did not reduce the number of dolphin entanglements. Human-wildlife conflict (1 study): One controlled study in the Gulf of Alaska found that attaching acrylic beads next to fishing hooks did not reduce predation on fish catches by sperm whales. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2806https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2806Thu, 04 Feb 2021 17:20:11 +0000Collected Evidence: Collected Evidence: Use acoustically reflective fishing gear materials Five studies evaluated the effects on marine mammals of using acoustically reflective fishing gear materials. Two studies were in the Bay of Fundy (Canada) and one study was in each of the Fortune Channel (Canada), the North Sea (Denmark) and the South Atlantic Ocean (Argentina). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (2 STUDIES) Behaviour change (2 studies): One controlled study in the Fortune Channel found that harbour porpoises approached nets made from acoustically reflective material (barium sulfate) and conventional nets to similar distances and for similar durations, but porpoises used fewer echolocation clicks at barium sulfate nets. One controlled study in the Bay of Fundy found that harbour porpoise echolocation activity was similar at barium sulfate and conventional nets. OTHER (3 STUDIES) Reduction in entanglements/unwanted catch (3 studies): Two of three controlled studies (including two replicated studies) in the North Sea, the Bay of Fundy and the South Atlantic Ocean found that fishing nets made from acoustically reflective materials (iron-oxide or barium sulfate) had fewer entanglements of harbour porpoises than conventional fishing nets. The other study found that nets made from barium sulfate did not reduce the number of dolphin entanglements. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2807https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2807Thu, 04 Feb 2021 17:31:28 +0000Collected Evidence: Collected Evidence: Use acoustic devices on fishing gear Thirty-three studies evaluated the effects on marine mammals of using acoustic devices on fishing gear. Eight studies were in the North Atlantic Ocean (Canada, USA, UK), four studies were in each of the North Pacific Ocean (USA) and the North Sea (Germany, Denmark, UK), three studies were in the Mediterranean Sea (Spain, Italy), two studies were in each of the Fortune Channel (Canada), the South Atlantic Ocean (Argentina, Brazil) and the Baltic Sea (Denmark, Germany, Sweden), and one study was in each of Moreton Bay (Australia), the Black Sea (Turkey), the Celtic Sea (UK), the South Pacific Ocean (Peru), the Rainbow Channel (Australia), the UK (water body not stated), the Great Belt (Denmark), Omura Bay (Japan), and the Indian Ocean (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (16 STUDIES) Behaviour change (16 studies): Twelve of 16 controlled studies (including three replicated studies) in the North Atlantic Ocean, the Fortune Channel, the South Atlantic Ocean, Moreton Bay, the Mediterranean Sea, the Celtic Sea, the Rainbow Channel, a coastal site in the UK, the Great Belt, the North Sea, Omura Bay and the Indian Ocean found that using acoustic devices on fishing nets, float lines or simulated fishing nets resulted in harbour porpoises, common bottlenose dolphins, tuxuci dolphins, finless porpoises and seals approaching nets or lines less closely, having fewer encounters or interactions with nets, or activity and sightings were reduced in the surrounding area. The other four studies found that using acoustic devices on trawl nets, float lines or simulated fishing nets did not have a significant effect on the behaviour of common bottlenose dolphins, harbour porpoises, Indo-Pacific humpback dolphins or dugongs. OTHER (19 STUDIES) Reduction in entanglements/unwanted catch (14 studies): Nine studies (including seven controlled studies and two before-and after studies) in the North Atlantic Ocean, the North Sea, the South Atlantic Ocean, the North Pacific Ocean, the Black Sea, and the South Pacific Ocean found that using acoustic devices on cod traps or fishing nets resulted in fewer collisions of humpback whales or entanglements of harbour porpoises, Franciscana dolphins, beaked whales and small cetaceans. Three studies (including two controlled studies and one before-and-after study) in the North Pacific Ocean found that using acoustic devices on fishing nets resulted in fewer entanglements of some species but not others. One controlled study in the North Atlantic Ocean found that fishing nets with a ‘complete’ set of acoustic devices had fewer entanglements of harbour porpoises, but those with an ‘incomplete’ set did not. One replicated, controlled study in the North Sea and Baltic Sea found that using acoustic devices on fishing nets reduced harbour porpoise entanglements in one fishing area but not the other. Human-wildlife conflict (6 studies): Five of six studies (including six controlled studies, one of which was replicated) in the Baltic Sea, the Mediterranean Sea, the North Pacific Ocean, a coastal site in the UK and the North Sea found that using acoustic devices reduced damage to fish catches and/or fishing nets caused by common bottlenose dolphins and seals. The other study found that acoustic devices did not reduce damage to swordfish catches by California sea lions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2808https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2808Thu, 04 Feb 2021 17:56:14 +0000Collected Evidence: Collected Evidence: Use acoustic devices on fishing vessels Five studies evaluated the effects on marine mammals of using acoustic devices on vessels. One study was in each of the Shannon Estuary (Ireland), the Rainbow Channel (Australia), Keppel Bay (Australia), the North Atlantic Ocean (Azores) and the Indian Ocean (Crozet Islands). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (4 STUDIES) Behaviour change (4 studies): One controlled study in the Shannon Estuary found that common bottlenose dolphins avoided a boat more frequently when acoustic devices of two types were deployed alongside it. One controlled study in the Indian Ocean found that killer whales were recorded further from a fishing vessel when an acoustic device was used during hauls, but distances decreased after the first exposure to the device. Two before-and-after studies in the Rainbow Channel and Keppel Bay found that an acoustic device deployed alongside a vessel reduced surfacing and echolocation rates and time spent foraging or socializing of Indo-Pacific humpback dolphins and Australian snubfin dolphins but there was no effect on 8–10 other types of behaviour (e.g. vocalizing, diving, travelling etc.). OTHER (1 STUDY) Human-wildlife conflict (1 study): One randomized, controlled study in the North Atlantic Ocean found that using acoustic devices of two types did not reduce predation of squid catches by Risso’s dolphins. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2815https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2815Fri, 05 Feb 2021 14:45:12 +0000Collected Evidence: Collected Evidence: Use acoustic devices on moorings Eight studies evaluated the effects on marine and freshwater mammals of using acoustic devices on moorings. Two studies were in the South Pacific Ocean and one study was in each of the Puntledge River (Canada), the Bay of Fundy (Canada), the Shannon Estuary (Ireland), the Rivers Conon and Esk (UK), the Kyle of Sutherland estuary (UK) and the North Atlantic Ocean (UK). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (7 STUDIES) Behaviour change (7 studies): Two of four controlled studies in the South Pacific Ocean, the Kyle of Sutherland estuary and the North Atlantic Ocean found that deploying acoustic devices on moorings reduced numbers of grey and harbour seals, and the activity of harbour porpoises, short-beaked common dolphins and common bottlenose dolphins. The two other studies found that using an acoustic device on a mooring did not have a significant effect on the number, direction of movement, speed, or dive durations of migrating humpback whales. One controlled study in the Bay of Fundy found that using an acoustic device on a mooring reduced harbour porpoise echolocation activity, but the probability of porpoises approaching within 125 m of the device increased over 10–11 days. One controlled study in the Shannon Estuary found that one of two types of acoustic device reduced the activity of common bottlenose dolphins. One replicated, controlled study in the Rivers Conon and Esk found that using acoustic devices reduced the number of grey and harbour seals upstream of the device but did not reduce seal numbers overall. OTHER (1 STUDY) Human-wildlife conflict (1 study): One randomized controlled study in the Puntledge River found that deploying an acoustic device on a mooring reduced the number of harbour seals feeding on migrating juvenile salmon. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2816https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2816Fri, 05 Feb 2021 15:00:49 +0000Collected Evidence: Collected Evidence: Use catch and hook protection devices on fishing gear Five studies evaluated the effects on marine mammals of using catch and hook protection devices on fishing gear. Two studies were in the South Pacific Ocean (Chile, Australia and Fiji), two were in the Indian Ocean (Seychelles, Madagascar) and one was in the Southwest Atlantic Ocean. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Reduction in entanglements/unwanted catch (1 study): One study in the South Pacific Ocean found that using cage or chain devices on fishing hooks resulted in fewer unwanted catches of toothed whales. Human-wildlife conflict (5 studies): Two of four studies (including three controlled and one before-and-after study) in the South Pacific Ocean, the Southwest Atlantic Ocean and the Indian Ocean found that net sleeves or cage and chain devices on fishing hooks reduced damage to fish catches by sperm whales, killer whales and toothed whales. The two other studies found that attaching ‘umbrella’ or ‘spider’ devices on fishing hooks did not reduce predation and/or damage to fish catches by sperm whales or toothed whales. One controlled study in the Indian Ocean found that attaching catch protection devices made from streamers to fishing lines reduced Indo-Pacific bottlenose and spinner dolphin predation on fish bait, but only during the first two trials. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2821https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2821Fri, 05 Feb 2021 15:18:24 +0000Collected Evidence: Collected Evidence: Modify fishing pots and traps to exclude mammals Six studies evaluated the effects on marine mammals of modifying fishing pots and traps to exclude mammals. Two studies were in the North Sea (UK, Sweden) and one study was in each of the Indian River Lagoon (USA), the Gulf of Finland (Finland), the Bothnian Sea (Finland), the Indian Ocean (Australia) and the Baltic Sea (Sweden). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (6 STUDIES) Reduction in entanglements/unwanted catch (2 studies): Two controlled studies (including one replicated study) in the Indian Ocean, and the Baltic Sea and North Sea found that installing steel rods on lobster pots or metal frames on fishing pots reduced the number of Australian sea lion pups or grey seals and harbour seals that entered or became trapped in pots. Human wildlife conflict (4 studies): Two controlled studies (including one replicated study) in the Bothnian Sea and the North Sea found that installing wire grids or steel bars on fishing trap-nets or bag-nets, along with strengthened netting or other modifications to prevent seal access, reduced damage to salmon catches by seals. One controlled study in the Indian River Lagoon found that one of two methods of securing crab pot doors with a bungee cord reduced the number of common bottlenose dolphin interactions. One controlled study in the Gulf of Finland found that installing wire grids on trap-nets, along with strengthened netting, resulted in higher catches of undamaged salmon but not whitefish, likely due to reduced seal predation. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2822https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2822Fri, 05 Feb 2021 15:35:30 +0000Collected Evidence: Collected Evidence: Install exclusion and/or escape devices for mammals on fishing nets Seven studies evaluated the effects on marine mammals of installing exclusion and/or escape devices on fishing nets. Four studies were in the Indian Ocean (Australia, Tasmania) and/or Tasman Sea (Tasmania) and three studies were in the South Atlantic Ocean (South Georgia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One study in the Indian Ocean found that less than one third of common bottlenose dolphins exited escape hatches on trawl nets alive. One replicated study in the Tasman Sea and Indian Ocean found that fewer fur seals died in exclusion devices with large escape openings than in those with small openings. BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Reduction in entanglements/unwanted catch (5 studies): Three studies (including two controlled studies) in the South Atlantic Ocean and Indian Ocean found that installing exclusion and/or escape devices on trawl nets reduced the number of trapped or entangled Antarctic fur seals and common bottlenose dolphins. One before-and-after study in the Indian Ocean found that installing exclusion and escape devices on trawl nets reduced common bottlenose dolphin entanglements for three of four fishing vessels. One study in the South Atlantic Ocean found that modifying an exclusion and escape device by enlarging and relocating the escape panel resulted in fewer Antarctic fur seal entanglements. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2823https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2823Fri, 05 Feb 2021 15:39:04 +0000Collected Evidence: Collected Evidence: Introduce and enforce regulations for marine and freshwater mammal watching tours Four studies evaluated the effects of introducing regulations for marine and freshwater mammal watching tours on marine mammals. One study was in each of the North Atlantic Ocean (the Azores), the Cananéia estuary (Brazil), the South Pacific Ocean (Australia) and the Bass Strait (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (4 STUDIES) Behaviour change (4 studies): Two controlled studies in the North Atlantic Ocean and South Pacific Ocean found that when whale-watching vessels followed approach regulations, fewer sperm whales and humpback whale pods changed their behaviours (e.g. swimming speed, aerial displays) or avoided the vessels compared to when regulations were not followed, but direction of movement and diving patterns or diving behaviours did not differ. One replicated, controlled study in the Cananéia estuary found that when tour boats followed approach regulations, fewer Guiana dolphins displayed negative behaviours (e.g. moving away, diving, groups separating). One study in the Bass Strait found that when boats approached a seal colony to 75 m, more seals remained on shore than when boats approached to 25 m. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2838https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2838Fri, 05 Feb 2021 16:16:26 +0000Collected Evidence: Collected Evidence: Use baited lines instead of nets for shark control Two studies evaluated the effects on marine mammals of using baited lines instead of nets for shark control. One study was in the Indian Ocean (South Africa) and one in the South Pacific Ocean (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One site comparison study in the South Pacific Ocean found that using baited lines instead of nets increased the survival of entangled common and bottlenose dolphins. BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Reduction in entanglements/unwanted catch (2 studies): Two site comparison studies in the Indian Ocean and South Pacific Ocean found that baited lines used for shark control had fewer entanglements of dolphins, whales and dugongs than nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2856https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2856Mon, 08 Feb 2021 11:13:28 +0000Collected Evidence: Collected Evidence: Use drugs to treat parasites Two studies evaluated the effects on marine mammals of using drugs to treat parasites. Both studies were in the North Pacific Ocean (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One of two controlled studies (including one before-and-after study) in the North Pacific Ocean found that treating northern fur seal pups with an anti-parasitic drug (ivermectin) reduced mortality rates. The other study found that Hawaiian monk seal pups treated with an anti-parasitic drug (praziquantel) had similar survival rates to untreated pups. Condition (2 studies): One of two controlled studies (including one before-and-after study) in the North Pacific Ocean found that northern fur seal pups treated with an anti-parasitic drug (ivermectin) had reduced hookworm infections and greater growth rates than untreated pups. The other study found that Hawaiian monk seal pups treated with an anti-parasitic drug (praziquantel) had similar parasite loads to untreated pups. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2861https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2861Mon, 08 Feb 2021 11:21:49 +0000Collected Evidence: Collected Evidence: Use acoustic devices to deter marine and freshwater mammals from an area to reduce noise exposure Four studies evaluated the effects of using acoustic devices to deter marine and freshwater mammals from an area to reduce noise exposure. Two studies were in the North Sea (Germany), one study was in the Great Belt (Denmark) and one was in Faxaflói Bay (Iceland). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (4 STUDIES) Behaviour change (4 studies): Three studies (including two controlled and one before-and-after study) in the North Sea and the Great Belt found that using acoustic devices to deter mammals from an area at a wind farm construction site or pelagic sites reduced the activity and sightings of harbour porpoises at distances of 1–18 km from the devices. One before-and-after study in Faxaflói Bay found that when an acoustic device was deployed from a boat, minke whales swam away from the device, increased their swimming speed, and swam more directly. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2896https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2896Mon, 08 Feb 2021 12:04:42 +0000Collected Evidence: Collected Evidence: Use ‘soft start’ procedures to deter marine and freshwater mammals to reduce noise exposure Three studies evaluated the effects of using ‘soft start’ procedures to deter marine and freshwater mammals to reduce noise exposure. One study was in each of the South Atlantic Ocean (Gabon), the South Pacific Ocean (Australia) and various water bodies (UK). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): One study in various water bodies around the UK found that a greater proportion of cetaceans (including whales, dolphins and porpoise) avoided or moved away from vessels during ‘soft start’ procedures with seismic airguns compared to when airguns were not firing. One study in the South Atlantic Ocean found that during ‘soft start’ procedures using seismic airguns, a pod of short-finned whales initially moved away but remained within 900 m of the vessel as it passed by. One study in the South Pacific Ocean found that during ‘soft-start’ procedures with a small experimental airgun array, migrating humpback whales slowed their speed towards the vessel but did not significantly alter their course. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2897https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2897Mon, 08 Feb 2021 12:12:04 +0000Collected Evidence: Collected Evidence: Legally protect habitat for marine and freshwater mammals Four studies evaluated the effects of legally protecting habitat for marine and freshwater mammals. One study was in each of the North Atlantic Ocean (Portugal), the South Pacific Ocean (New Zealand), the North Sea (UK) and the Port River estuary (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (4 STUDIES) Abundance (2 studies): One before-and-after study in the North Atlantic Ocean found that a population of Mediterranean monk seals increased during eight years after the islands they inhabited were legally protected. One before-and-after study in the North Sea found that a population of bottlenose dolphins was estimated to be a similar size before and after part of its range was protected. Survival (2 studies): One before-and-after study in the South Pacific Ocean found that the survival rate of Hector’s dolphins was higher after a coastal area was legally protected than before. One before-and-after study in the Port River estuary found that after the area became legally protected a similar number of Indo-Pacific bottlenose dolphin strandings were recorded compared to before protection, but the number of strandings caused by humans decreased. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2915https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2915Mon, 08 Feb 2021 16:29:11 +0000Collected Evidence: Collected Evidence: Rescue and release stranded or trapped marine and freshwater mammals Eleven studies evaluated the effects of rescuing and releasing stranded or trapped marine and freshwater mammals. Five studies were in the North Atlantic Ocean (USA), two studies were in the Indian Ocean (Tasmania, South Africa), and one study was in each of the South Atlantic Ocean (Brazil), the Cachoeira River estuary (Brazil), the North Pacific Ocean (USA) and the Shannon Estuary (Ireland). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (11 STUDIES) Reproductive success (2 studies): One review in the North Pacific Ocean found that after rescuing and releasing stranded or trapped Hawaiian monk seals, along with at least seven other interventions to enhance survival, more than a quarter of the seals reproduced. One study in the Shannon Estuary found that a stranded common bottlenose dolphin that was rescued and released was observed with a calf a year later. Survival (11 studies): Seven studies (including one review) in the North Atlantic Ocean, Indian Ocean and the Shannon Estuary found that 17–100% of rescued and released Atlantic white-sided dolphins, short-beaked common dolphins, common bottlenose dolphins, long-finned pilot whales, short-finned pilot whales, and Cape fur seals survived during post-release monitoring periods, which ranged in length from three weeks to three years. Three studies in the South Atlantic Ocean, the Cachoeira estuary and the Indian Ocean found that a trapped rough-toothed dolphin, two stranded tucuxi dolphins and seven stranded sperm whales were successfully rescued and released, although long-term survival was not reported. One review in the North Pacific Ocean found that rescuing and releasing stranded or trapped Hawaiian monk seals, along with at least seven other interventions to enhance survival, resulted in more than a quarter of the seals surviving. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2924https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2924Mon, 08 Feb 2021 16:51:49 +0000Collected Evidence: Collected Evidence: Rehabilitate and release injured, sick or weak marine and freshwater mammals Twenty-seven studies evaluated the effects of rehabilitating and releasing injured, sick or weak marine and freshwater mammals. Nine studies were in the North Atlantic Ocean (USA, UK, France), six studies were in the North Pacific Ocean (USA), four studies were in the Gulf of Mexico (USA), two studies were in each of the North Sea (the Netherlands) and the Gulf of Maine (USA), and one study was in each of the Indian River Lagoon (USA), Bohai Bay (China), The Wash estuary (UK), water bodies in Florida (USA), El Dorado Lake (Peru), and the Gulf of California (Mexico). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (26 STUDIES) Reproductive success (1 study): One replicated study in the North Pacific Ocean found that more than a quarter of rehabilitated and released Hawaiian monk seals reproduced. Survival (26 studies): Twenty-one studies (including two controlled studies, four replicated studies and one review) in the North Atlantic Ocean, the Gulf of Maine, the Gulf of Mexico, the North Pacific Ocean, the Indian River Lagoon, The Wash estuary, water bodies in Florida, El Dorado Lake, and the Gulf of California found that 10–100% of dolphins, porpoises, whales, seals, sea lions and manatees released after rehabilitation in captivity survived during post-release monitoring periods, which ranged in length from three days to five years. Five studies (including one replicated study) in the North Sea, the North Atlantic Ocean, Bohai Bay and the North Pacific Ocean found that two of three harbour porpoises, 152 of 188 grey seal pups, a common seal, a west Pacific finless porpoise and 14 of 35 California sea lions were successfully rehabilitated and released but survival after release was not reported. One controlled study in the North Pacific Ocean found that at least a quarter of California sea lions treated for toxic algae poisoning and released back into the wild died or had to be euthanized. BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): Two of three controlled studies in the North Atlantic Ocean, the North Pacific Ocean and The Wash estuary found that a harbour porpoise and six harbour seals that were rehabilitated and released had similar movements and/or behaviours to wild mammals. The other study found that California sea lions treated for toxic algae poisoning and released travelled further from the shore, spent less time diving or hauled out and made shorter, shallower dives than wild sea lions without poisoning. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2925https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2925Mon, 08 Feb 2021 16:57:11 +0000Collected Evidence: Collected Evidence: Hand-rear orphaned or abandoned marine and freshwater mammal young Twelve studies evaluated the effects of hand-rearing orphaned or abandoned marine and freshwater mammal young. Four studies were in the North Pacific Ocean (USA), two studies were in captive facilities (USA), and one study was in each of the North Atlantic Ocean (USA), the Indian River Lagoon (USA), the Salish Sea (USA), the Guerrero Lagoon (USA), the South Atlantic Ocean (Brazil) and water bodies in Florida (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (11 STUDIES) Reproductive success (1 study): One replicated study in the South Atlantic Ocean found that most captive-reared Antillean manatees released back into the wild reproduced. Survival (11 studies): Three studies (including one replicated and controlled study) in the North Pacific Ocean, and the Indian River Lagoon found that a gray whale calf, three Steller sea lion pups, and a common bottlenose dolphin calf that were released after being reared in captivity survived during post-release monitoring periods of between three days to three months. Two replicated studies in the South Atlantic Ocean and water bodies in Florida found that approximately three-quarters of Antillean manatees and two-thirds of Florida manatees that were captive-reared and released were known to survive for at least one year, and some survived for more than seven years. Three studies in the North Atlantic Ocean, the North Pacific Ocean and the Guerrero Lagoon found that three West Indian manatee calves, seven Hawaiian monk seal pups and one Antillean manatee calf that were captive-reared either died before or after release, had to be returned to captivity after release, or survived in the wild only with supplemental feeding. Two studies at captive facilities found that a captive-reared grey whale calf and five pygmy and dwarf sperm whale calves increased in body weight but were either not released or died in captivity. One controlled study in the North Pacific Ocean found that captive-reared, released Pacific harbour seal pups had similar survival estimates to wild pups. BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): Two controlled studies (including one replicated study) in the North Pacific Ocean found that captive-reared and released Pacific harbour seal pups and Steller sea lion pups had similar diving behaviour to wild pups. One controlled study in the Salish Sea found that captive-reared and released harbour seal pups travelled greater distances and further from the release site than wild pups born at the same site and in the same season. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2926https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2926Tue, 09 Feb 2021 10:51:31 +0000Collected Evidence: Collected Evidence: Translocate marine and freshwater mammals to re-establish or boost native populations Four studies evaluated the effects of translocating marine mammals to re-establish or boost native populations. The four studies were in the North Pacific Ocean (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (4 STUDIES) Reproductive success (2 studies): One replicated study and one review in the North Pacific Ocean found that after translocating Hawaiian monk seals, along with rehabilitation or at least seven other interventions to enhance survival, more than a quarter of the seals reproduced. Survival (4 studies): Two studies (including one replicated and one controlled study) in the North Pacific Ocean found that 50–83% of translocated, and 52% of rehabilitated and translocated, Hawaiian monk seal pups survived for at least one year. One of the studies and one review in the North Pacific Ocean found that translocated seal pups had similar survival rates to non-translocated pups born at release sites or greater survival rates than non-translocated pups remaining at the original site. One review in the North Pacific Ocean found that translocating Hawaiian monk seals, along with at least seven other interventions to enhance survival, resulted in more than a quarter of the seals surviving. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One review in the North Pacific Ocean found that translocated Hawaiian monk seal pups had similar dispersal times to non-translocated seal pups born at release sites. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2930https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2930Tue, 09 Feb 2021 11:11:40 +0000Collected Evidence: Collected Evidence: Breed marine and freshwater mammals in captivity Six studies evaluated the effects of breeding marine and freshwater mammals in captivity. Three studies were in the USA, one study was also in China, Indonesia and Venezuela, and one study was in each of South Africa, Hong Kong and China. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (6 STUDIES) Reproductive success (2 studies): One study in Hong Kong found that four of six female Indo-Pacific dolphins successfully conceived during a controlled captive breeding programme and gave birth to a total of nine calves. One study in China found that wild-caught Yangtze finless porpoises successfully reproduced in semi-captive conditions. Survival (4 studies): Two studies in South Africa and the USA found that a captive-born common bottlenose dolphin, and a captive-born and hand-reared common bottlenose dolphin, survived in captivity for at least two and a half years and four years respectively. One review in the USA found that 80% of common bottlenose dolphins born in captivity over two decades survived, and survival increased with improved husbandry techniques. One review in the USA, China, Indonesia and Venezuela found that most captive-born Amazon river dolphins, narrow-ridged finless porpoises and Irrawaddy dolphins did not survive in captivity. Condition (1 study): One study in China found that a population of Yangtze finless porpoises breeding in semi-captive conditions had low genetic diversity. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One study in the USA found that a captive-born and hand-reared common bottlenose dolphin displayed normal behaviour for the species and joined a dolphin social group in captivity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2932https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2932Tue, 09 Feb 2021 11:30:25 +0000Collected Evidence: Collected Evidence: Educate the public to improve behaviour towards marine and freshwater mammals Three studies evaluated the effects of educating the public to improve behaviour towards marine and freshwater mammals. One study was in each of the North Atlantic Ocean (USA), the Sundarbans mangroves (Bangladesh) and the South Pacific Ocean (Peru). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (3 STUDIES) Change in human behaviour (3 studies): Three before-and-after studies in the North Atlantic Ocean, the Sundarbans mangroves and the South Pacific Ocean found that after educational whale-watching tours or an educational exhibition, participants were more willing to change their behaviour to support marine conservation, to donate money to marine conservation, or to cut their fishing nets to save entangled dolphins. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2935https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2935Tue, 09 Feb 2021 11:41:45 +0000
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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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