Resource Ecology & Ecosystem Modeling (REEM) Program

Seabird Interactions

In the 2003 Biological Opinion on the total allowable catch setting process for short-tailed albatross, Phoebastria albatrus, NMFS was required to “…work on a safe and reliable means of assessing short-tailed albatross interactions/collisions with trawl vessel gear to 1) document whether take occurs, and if so, 2) estimate the rate of such take…” To date, no observers have reported collisions between short-tailed albatross and trawl gear. Observers do not, however, directly monitor trawl gear during the towing process.

We initiated several collaborative studies to look at the possibility of these interactions through fishery characterization, risk assessments, and decision analysis. One such study was recently completed by Stephanie Zador, Andre Punt, and Julia Parrish of the University of Washington. They conducted a decision analysis that explores the effects of trawl-related fisheries mortality on achieving the population recovery goals for the short-tailed albatross. In their study, “Bayesian inference was used to assign probabilities to alternative plausible rates of fishing mortality and to conduct population projections with different levels of trawl mortality to determine their effects on achieving the population recovery goals.

The analyses of the impact of trawl mortality on the Torishima short-tailed albatross population suggests that exceeding the current expected incidental take in the Alaska groundfish trawl fishery, two in any five year period, by as much as a factor of 10 would have little impact on when the proposed recovery goals for the species are achieved.” An example of their findings is noted in Table 1 (below) excerpted from their paper.

By Shannon Fitzgerald