Shrnutí

Popis

In 1991, NMML initiated cetacean studies with vessel coverage throughout inland waters of Southeast Alaska. Between 1991 and 1993, line-transect methodology was used to: 1) obtain population estimates of both harbor porpoise and Dalls porpoise, 2) establish a baseline for detecting trends in porpoise abundance, and 3) define porpoise distributional patterns and seasonality. Three line-transect surveys were carried out each year spanning spring, summer, and fall. To update abundance and trends for both harbor porpoise and Dalls porpoise, NMML once again initiated line-transect surveys in 2006 (spring and summer), 2007 (spring, summer and fall), 2010 (summer and fall), 2011 (summer and fall), and 2012 (summer) using methods comparable to those used in the early 1990s.