OneNOAA Science Seminar Series: Quantifying the Overlap of Trawl Fisheries With Deep-Sea Corals and Sponges in the Aleutians Islands, Alaska

Speaker: John Olson - NOAA Fisheries Alaska Regional Office

Event Type: Webinars and Virtual Events

When: 16 April 2020

Where: Online: 11:00 - 11:30 am AKDT, 3:00 - 3:30 pm EDT

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Deep-sea coral and sponge communities in the Aleutian Islands are important habitat features for many life stages of commercially important fish targets, including Atka mackerel, Pacific cod, and rockfish. The effects of commercial fishing activities on deep-sea corals and sponges has been difficult to quantify due to a lack of spatially-explicit fishery data, bottom contact by different gear types, undetermined location of corals and sponges, and the susceptibility and recovery dynamics these structure-forming invertebrates (SFI). To address these challenges, a fishing effects model was developed in the North Pacific to integrate spatially explicit VMS data with target-specific gear configurations for over 40,000 bottom trawls since 2003. Fishery observer coverage for Aleutian Island trawl fisheries is nearly 100 percent and records catch species composition. Species distribution models provide presence data for coral, sponge, Primnoidae, and Stylasteridae. A simple spatial overlap analysis of the trawl footprint indicates trawl fisheries are extremely aggregated and spatially distinct for three main targets – mackerel, cod, and rockfish. Across the Aleutian Islands, trawl fisheries affect less than 10% of areas of the highest probability of presence for SFIs. Patterns in spatial variation exist longitudinally, from about 5% in the eastern, 10% in the central, and 20% in the western Aleutians. This footprint analysis depicts maximum overlap, as it does not account for bottom contact, estimated at between 20 and 100% for AI fisheries, or susceptibility or recovery of SFIs. However, this analysis does provide valuable information for fishery managers evaluating impacts on SFIs.

Sponsor: NOAA Deep Sea Coral Research and Technology Program

Point of Contact: heather.coleman [at] (301-427-8650)

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For audio: Participants can use their computer speakers or call 415-655-0060 followed by passcode 654-149-455.

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Link to OneNOAA Science Seminars