Physical Sciences and Mathematics Commons^™

What’S The Catch? Patterns Of Cetacean Bycatch And Depredation In Hawaii-Based Pelagic Longline Fisheries, Karin A. Forney, Donald R. Kobayashi, David W. Johnston, Jamie A. Marchetti, Michael G. Marsik

United States Department of Commerce: Staff Publications

U.S. Pacific pelagic longline fisheries operating in the central North Pacific have been subject to a series of regulations to reduce bycatch of protected species, including seabirds and sea turtles. Cetaceans are also occasionally caught, and the bycatch of false killer whales, Pseudorca crassidens, in the Hawaii-based deep-set longline fishery currently exceeds allowable levels under the Marine Mammal Protection Act (MMPA). In this study, we examined longline observer data collected between 1994 and 2009, with emphasis on 2003–2009, to identify patterns of cetacean bycatch and depredation in relation to area, time, vessel, habitat variables, fishing gear, and set characteristics. …

Small-Scale Fisheries Of Peru: A Major Sink For Marine Turtles In The Pacific, Joanna Alfaro-Shigueto, Jeffrey C. Mangel, Francisco Bernedo, Peter H. Dutton, Jeffrey A. Seminoff, Brendan J. Godley

United States Department of Commerce: Staff Publications

1. Over the last few decades, evidence of marine vertebrate bycatch has been collected for a range of industrial fisheries. It has recently been acknowledged that large impacts may also result from similar interactions with small-scale fisheries (SSF) due largely to their diffuse effort and large number of vessels in operation. Marine mammals, seabirds, turtles as well as some shark species have been reported as being impacted by SSF worldwide.

2. From 2000 to 2007, we used both shore-based and onboard observer programmes from three SSF ports in Peru to assess the impact on marine turtles of small-scale longline, bottom …

Field Experiments Show That Acoustic Pingers Reduce Marine Mammal Bycatch In The California Drift Gill Net Fishery, Jay Barlow, Grant A. Cameron

United States Department of Commerce: Staff Publications

A controlled experiment was carried out in 19961997 to determine whether acoustic deterrent devices (pingers) reduce marine mammal bycatch in the California drift gill net fishery for swordfish and sharks. Using Fisher’s exact test, bycatch rates with pingers were significantly less for all cetacean species combined (P < 0.001) and for all pinniped species combined (P = 0.003). For species tested separately with this test, bycatch reduction was statistically significant for shortbeaked common dolphins (P = 0.001) and California sea lions (P = 0.02). Bycatch reduction is not statistically significant for the other species tested separately, but sample sizes and statistical power were low, and bycatch rates were lower in pingered nets for six of the eight other cetacean and pinniped species. A log-linear model relating the mean rate of entanglement to the number of pingers deployed was fit to the data for three groups: short-beaked common dolphins, other cetaceans, and pinnipeds. For a net with 40 pingers, the models predict approximately a 12- fold decrease in entanglement for short-beaked common dolphins, a 4-fold decrease for other cetaceans, and a 3-fold decrease for pinnipeds. No other variables were found that could explain this effect. The pinger experiment ended when regulations were enacted to make pingers mandatory in this fishery.