Section 10 Assessment of Gulf of Alaska Atka Mackerel (partial Chapter)

Relative to the November 1999 SAFE report, the following substantive changes have been made in the current draft of the Atka mackerel chapter: Changes in the Input Data Catch data are updated. Changes in the Assessment Methodology There are no changes in the assessment methodology Changes in Assessment Results There are no changes in assessment results Response to SSC comments There were no SSC comments pertaining to the Atka mackerel assessment from the December 1999 SSC minutes. In this assessment the following issues are highlighted: • Rationale for maintaining separate Bering Sea/Aleutian Islands and Gulf of Alaska Atka mackerel assessments is provided. • There is no reliable estimate of current biomass from the Gulf of Alaska bottom trawl survey. Using Tier 6 criteria, overfishing level is set equal to the average catch from 1978-95, which equals 6,200 mt. • Given that: a) there is no reliable estimate of current biomass, b) Leslie estimates of local population sizes suggest that abundance has declined significantly in localized areas from 1992-94, and c) the species has exhibited vulnerability to fishing pressure in the past, it is recommended that the ABC for Atka mackerel in the GOA be 600 mt, enough to satisfy only the anticipated bycatch needs of other trawl fisheries, principally those for Pacific cod, rockfish and pollock.