Forney et al.: Abundance of cetaceans in California waters: aerial surveys 



25 



on its size and was not sighted during this survey. It 

 is likely that the categorization of "small beaked 

 whales" will be necessary on future aerial surveys. 

 The survey grid used here was not designed for 

 species which are restricted to a narrow coastal re- 

 gion. Harbor porpoise are found primarily in waters 

 inshore of the 50-fathom (92-m) isobath (Barlow, 

 1988). Two distinct populations of bottlenose dolphins 

 are found in California; the inshore form is found only 

 within about 1 km of shore (Hansen, 1990; NMFS 8 ). 

 All of the bottlenose dolphins seen during this aerial 

 survey were at least several miles from the main- 

 land; therefore our estimate is assumed to represent 

 the population of offshore animals. Precise estimates 

 of abundance for harbor porpoise and inshore bottle- 

 nose dolphins will require dedicated aerial surveys 

 designed for those species. Work is currently in 

 progress on both of these projects. 8 



Acknowledgments 



Funding for this project was provided by the Office 

 of Protected Species, U.S. Department of Commerce. 

 The aircraft was provided by the NOAA Aircraft 

 Operations Center. We express special thanks to the 

 pilots: T O'Mara, J. Vance, P. Wehling, and M. White. 

 We are grateful to the meteorological staff of the 

 National Weather Service for their valuable assis- 

 tance in planning flights. Observers were D. Ever- 

 hart, S. Kruse, C. LeDuc, R. LeDuc, and M. Lycan 

 (also J. B., J. V. O, and K. A. F). Survey design was 

 improved by comments from D. Ainley, H. Braham, 

 S. Buckland, K. P. Burnham, D. DeMaster, D. 

 Goodman, T Gerrodette, L. Hansen, W Hoggard, D. 

 Palka, and T Polacheck. Data recording software was 

 developed by J. Cubbage (and J. B.). An earlier draft 

 of this manuscript was reviewed by the participants 

 of the Status of California Cetacean Stocks Work- 

 shop in March- April 1993; we thank all for their ef- 

 forts and reviews. The submitted manuscript was 

 reviewed by J. Calambokidis, R. Hobbs, and an 

 anonymous reviewer. Surveys were conducted under 

 Marine Mammal Protection Act permit 748 and per- 

 mits GFNMS-01-92 and CINMS-01-92 from the Na- 

 tional Marine Sanctuary Program. 



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