| Summary: | Satellite tags were attached to 10 sperm whales Physeter macrocephalus (1 whale was tagged in 2 different years) to determine the movements of sperm whales involved in removal of sablefish from longline fishing gear in the Gulf of Alaska (GOA). Tags transmitted from 3 to 34 d (median = 22) in 2007 and 7 to 158 d (median = 45) in 2009. Seven whales stayed in the GOA; all were associating with fishing vessels along the slope. Two whales headed south in June shortly after being tagged; one reached the inner third of the Sea of Cortez; the other’s last location was offshore Mexico at 14°N. A third whale stayed in the GOA until October and then headed south, reaching central Baja, Mexico, 158 d after tagging. The whales that travelled to lower latitudes followed no pattern in timing of departure, and at least 2 had different destinations. All whales passed through the California Current without stopping and did not travel to Hawaii; both are areas with known concentrations of sperm whales. Whales travelled faster when south of 56°N than when foraging in the GOA (median rate of median horizontal movement = 5.4 [range: 4.1 to 5.5] and 1.3 [range: 0.6 to 2.5] km h−1, respectively). Tagged sperm whales primarily travelled over the slope, but one spent considerable time over the ocean basin. Information on the timing and movement patterns of sperm whales may provide a means for fishermen to avoid fishing at whale hot spots, potentially reducing interactions between whales and fishermen. Acknowledgements. The authors thank Jennifer Cedarleaf, Lauren Wild, Delphine Mathias, Nellie Warner, Kendall Folkert and the crew of the F/V Cobra, and the crews of the F/V Ocean Prowler and Alaskan Leader for their assistance, and Sarah Mesnick for sharing results of ongoing genetic studies. Funding was provided by North Pacific Research Board, NOAA Fisheries TSMRI Auke Bay Lab sablefish assessment program, and NOAA grants to the Alaska Fisheries Science Center and Alaska Sea Life Center. Katy Echave created the wonderful maps of the ...
|
|---|