A cost effective approach to protecting deep-sea coral and sponge ecosystems with an application to Alaska’s Aleutian Islands region

Abstract

There is much debate about how to protect deep-sea coral and spongeecosystems using the data currently available. The Aleutian Islands inAlaska contain some of the most abundant, diverse, and pristine deep-seacoral and sponge ecosystems on Earth. From 1990 to 2002, U.S. federalfishery observer data indicates approximately 2,176,648 kg of coral andsponge bycatch occurred in the Aleutian Islands, equaling 52 % of allcoral and sponge bycatch in Alaska. Coral and sponge bycatch rates inthe Aleutians were over 12 times the rate in the Bering Sea or Gulf ofAlaska. The National Marine Fisheries Service (NMFS) estimates that 87% of coral bycatch and 91 % of sponge bycatch is caused by bottomtrawling in the Bering Sea/Aleutian Islands management areas. Theconservation organization Oceana developed an interdisciplinary fisherymanagement approach to mitigating adverse impacts of fishing on deep-seacoral and sponge ecosystems, which has been used by NMFS to formulate ahabitat protection alternative for the Aleutian Islands that is beingconsidered in an Environmental Impact Statement. The Oceana Approach isoffered as a cost effective model for reducing the adverse effects offishing on deep-sea coral and sponge ecosystems. The approach usesobserver data to identify areas of high coral and sponge bycatch ratesto develop a comprehensive management policy that allows bottom trawlingonly in specific designated areas with high fish harvest and low habitatimpacts. All areas not specified as open would be closed to bottomtrawling. To prevent effort displacement, bottom trawl effort is reducedby the amount that historically occurred in areas that would becomeclosed. The Oceana Approach also includes coral and sponge bycatchlimits and a plan for comprehensive seafloor research, mapping, andmonitoring. An enforcement strategy for these management measures isdeveloped based on agency capabilities, and includes increased observercoverage, vessel monitoring systems, and electronic logbooks. Thisapproach allows for continued catch of target species with minimaladverse impacts on coral and sponge habitat. Successful implementationof the Oceana Approach will protect areas of high known trawl impacts todeep-sea coral and sponge ecosystems and prevent trawl effort frommoving into new, unexplored areas. The methodology is recommended forapplication to other regions and should be adjusted based on theavailable fishery and biological data for each region.