Research on large whales off California, Oregon, and Washington: Annual report for 2003

Publications >> Research on large whales off California, Oregon, and Washington: Annual report for 2003

Citation

Calambokidis, J., T. Chandler, E. Falcone, and A. Douglas. 2004. Research on large whales off California, Oregon, and Washington: Annual report for 2003.  Final report to Southwest Fisheries Science Center, La Jolla, CA.  Cascadia Research, 218½ W Fourth Ave., Olympia, WA 98501.  48pp

Executive summary

This report summarizes fieldwork conducted by Cascadia Research and collaborators in 2003 on humpback, blue, fin and gray whales off California, Oregon, and Washington and also summarizes work conducted under NMFS permit #540-1502-00 in 2003. Principal support for this research was from Southwest Fisheries Science Center to assess population size and trends (Contract # 50ABNF100065) with additional support from Office of Naval Research, Office of Naval Operations, National Marine Mammal Laboratory, and the Olympic Coast National Marine Sanctuary.  

Identification photographs in 2003 came from a number of sources and survey types including 65 days of dedicated research surveys under Permit 540-1502-00 conducted by Cascadia Research off California, Oregon, and Washington. Photographic identification was also conducted on either an opportunistic basis by others who provided photographs to Cascadia or as part of collaborative research under other permits.   
A total of 542 humpback whale identifications were obtained in all effort off California, Oregon, and Washington in 2003 representing 398 unique individuals. Of the 398 identified whales, 98 were seen two or more times during the year. Rates of interchange of animals were highest among adjacent years and decreased progressively with distance to the north or south. Abundance estimates of humpback whales from mark-recapture revealed a surprising jump to 1,391, about 400 animals higher than any previous estimate. Estimates of humpback abundance along the west coast from our previous work had revealed a steady increase in abundance of about 8% per year through 1998, after which there was a dramatic drop in abundance. The current high estimates appear to be the result of an influx of whales into the region that had not been seen in previous years.

Blue whale identifications were made from southern California to British Columbia in 2003 with 534 identifications of 292 unique individuals in 2003. Movements of blue whales within 2003 were fairly extensive; animals were resighted all along the California coast in 2003. A single blue whale identified off the southwest end of the Queen Charlotte Islands, British Columbia on 7 August 2003 was an animal that had been seen eight times from 1988 to 2001 off California. This is the second animal identified off British Columbia with both matching identifications off California. The only previous whale identified off British Columbia was ID# 1110, seen on 12 June 1997 and then resighted on 1 and 14 July in the Santa Barbara Channel. While 2003 data did not directly contribute to a new estimate of blue whale abundance, we were able to update our most recent estimate from mark recapture to 1,781 blue whales for 2000 to 2002.   

Tagging in 2003 consisted of 41 deployments of four instrument packages on blue, fin, and humpback whales. The vast majority of the tag deployments in 2003 were of the Burgess acoustic tag. Deployments in Monterey Bay were conducted in collaboration with Scripps Institute of Oceanography, Moss Landing Marine Labs, and UC Santa Cruz and yielded dive data in conjunction with hydro-acoustic mapping of prey fields. Combined dive, pitch, and roll data from the Burgess tags have provided insights into the diving dynamics of blue whales. These tags have also contributed insights into the vocal behavior of blue whales including indications that it is only the males that produce the long loud repeated calls generally described for blue whales but that both sexes produce the shorter more variable D-type call. Satellite tag data for the five humpback and two blue whales provided movement data on both species over only about a 2-week period.   

A total of 97 skin samples were collected off California, Oregon, and Washington in 2003 under our permit. Of these, 71 were from biopsies and 26 were small pieces of skin collected from the suction-cups and other parts of the tagging apparatus. Skin samples were collected from 40 fin whales, 28 blue whales, 21 humpback whales, and 8 gray whales.   

Reaction of whales to the various research activities was generally mild. Most animals that were approached for photographic identification did not exhibit any detectable behavioral reaction to the boat. A total of 51 whales were approached to attach tags and these close approaches for tagging generally resulted in some reaction from the whales, which appeared to be from the close approach of the boat. The most typical response was a suspension of the surface series (where the animal would resurface after a slightly longer surface interval) or a termination of the surface series. There were 103 approaches of animals to obtain a biopsy; a clear reaction to either the approach or the biopsy was seen in slightly less than half of these instances. Reactions were most common to biopsy hits than to misses and humpback whales showed observable reactions at a much higher rate than blue or fin whales. 

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