Reducing impacts of trawling on protected sea snakes: by-catch reduction devices improve escapement and survival

Published source details Milton D.A., Fry G.C. & Dell Q. (2009) Reducing impacts of trawling on protected sea snakes: by-catch reduction devices improve escapement and survival. Marine and Freshwater Research, 60, 824-832.
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This study is summarised as evidence for the following.

	Action	Category
	Install escape devices on fishing gear: Snakes & lizards Action Link

Install escape devices on fishing gear: Snakes & lizards

A replicated, paired, controlled study in 2004–2006 in benthic waters in the Gulf of Carpentaria, Australia (Milton et al. 2009) found that adding escape hole devices (‘bycatch reduction device’) ≤70 meshes from the codend of trawl nets in reduced unwanted catch of sea snakes compared to unmodified nets in a prawn fishery. Nets modified with escape hole devices located 30–70 meshes from the codend caught fewer sea snakes (82–168 snakes/trawl) compared to unmodified nets (99–350). Nets modified with devices located 120 meshes from the codend caught similar numbers of sea snakes (148–418 snakes/trawl) to unmodified nets (155–430). Unwanted catch of sea snakes was similar between three different escape hole devices (see paper for individual device details). Catch of commercially targeted prawns Penaeus spp. was similar between modified and unmodified nets, regardless of the location of the escape hole (see paper for details). In August–November 2004–2006, nets on commercial trawlers (10–15 trawlers/year) were modified with an oval framed ‘fish eye’ (930 trawls), a square-mesh panel (435 trawls), or a square opening with metal funnel below a rigid frame (‘popeye’ Fishbox design, 54 trawls) located 30–120 meshes from the codend. Trawlers fished pairs of modified and unmodified nets, one on either side of the boat (the modified net was switched sides approximately fortnightly). Turtle excluder devices (frames in front of the codend with escape holes) were mandatory and used on all nets. Crew and independent scientific observers identified sea snakes landed with catch.

(Summarised by: Katie Sainsbury)