Establish handling and release protocols for mammals captured by fisheries
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Establishing best practice protocols for handling and releasing marine and freshwater mammals entangled or captured in fishing gear may reduce the risk of injury and improve post-release survival. This may involve releasing mammals without delay, using appropriate techniques to remove fishing gear from entangled or hooked mammals, and using appropriate procedures to release mammals encircled in nets. See also Provide training and tools for safe release of mammals captured by fisheries.
For an intervention related to releasing mammals from derelict fishing gear, see Remove derelict fishing gear from mammals found entangled.
Supporting evidence from individual studies
A before-and-after study in 2004–2006 of a pelagic area in the Great Australian Bight, Australia (Hamer et al. 2008) found that introducing a code of practice for releasing dolphins trapped in fishing nets, along with avoiding dolphins during fishing, resulted in fewer deaths of short-beaked common dolphins Delphinus delphis. The study did not distinguish between the effects of releasing and avoiding dolphins. Mortality rates of dolphins in purse-seine nets were lower after the code of conduct was put in place (0.01 dolphins killed/net) than before (0.4 dolphins killed/net). The code of practice was introduced to a sardine Sardinops sagax fishery in September 2005. At least one crew member/vessel was required to observe for dolphins. Fishing was delayed or relocated if dolphins were present. Release procedures for encircled dolphins included opening the net or a dolphin gate within the net, using weights to submerge the float line, physical removal of dolphins or stopping fishing. An independent observer recorded dolphin encirclements and deaths during 49 fishing events by eight vessels in November–June 2004/2005 (before the code of conduct) and 89 fishing events by 12 vessels in November–June 2005/2006 (after).Study and other actions tested