Witteveen et al : Effect of prey removal by Megaptera novaeangliae on fisti abundance 



1-" 1 nil w 



I 



I 



A 



Muniiot Bity 

 Cbiniak Bav 



2 



Woody Island 



Long Island 



iKilomelers 



Figure 1 



Map of Kodiak Island study area. Study area is shown as shaded area and subareas (1-4) are outlined and 

 numbered. In detail is the nearshore subarea between Woody Island and Long Island. 



last), walleye pollock {Theragra chalcogramma). Atka 

 mackerel iPleurogrammus monopterygius), cod (Gadus 

 spp.). sardines {Sardinops spp. ), and sandlance (Ammo- 

 dytes spp.) (Nemoto, 1957, 1959; Mitchell, 1973; Payne 

 et al., 1990). The variety, as well as the amount, of 

 prey removed from Kodiak waters may therefore be 

 significant. Resource removal from Kodiak waters is of 

 particular importance when considering the high value 

 of Kodiak Island commercial fisheries, which totaled 

 63.3 million dollars in exvessel (wholesale) value in 

 2002 (NMFS2). 



Modeling consumption by humpback whales as they 

 recover from severe population declines could shed light 

 on patterns of change seen in prey and sympatric con- 

 sumer populations, such as marine birds and pinnipeds 

 (Merrick, 1997; Anderson and Piatt, 1999). Commercial 

 whaling in the 1900s significantly reduced the number 

 of humpback whales, both within coastal Kodiak waters 

 and throughout the North Pacific (Rice, 1978). Following 



the protection of humpback whales in 1965, however, 

 their numbers in the central North Pacific increased, 

 possibly by as much as 10%, between the early 1980s 

 and early 1990s for some North Pacific stocks (Baker 

 and Herman, 1987; Calambokidis et al.'^). Removal and 

 subsequent recovery of a marine predator of this magni- 

 tude may cause large variations in the biomass removal 

 of prey in the ecosystem, as has been hypothesized in 

 other studies (Laws, 1985; Springer et al., 2003). How- 

 ever, no empirical evidence exists to demonstrate such 

 trophic interactions in the Gulf of Alaska. In this article, 



2 NMFS (National Marine Fisheries Service). 2002. Unpubl. 

 data. Website: http://www.st.nmfs.gov/pls/webpls/MF_ 

 LPORT.YEARD. RESULTS (Accessed on 31 May 2003.1 



3 Calambokidis, J., G. H. Steiger, J. M. Straley, T. Quinn, L. 

 M. Herman, S. Cerchio, D. R. Salden, M. Yamaguchi, F. Sato, 

 J. R. Urban, J. Jacobson, O. von Ziegesar, K. C. Balcomb, 

 C. M. Gabriele, M. E. Dalheim, N. Higashi, S. Uchida, J. 

 K. B. Ford, Y. Miyamura, P. Ladron de Guevara, S. A. Miz- 

 roch, L. Schlender, and K. Rasmussen. 1997. Abundance 

 and population structure of humpback whales in the North 

 Pacific basin. Cascadia Research Cooperative Final Con- 

 tract Report 50ABNF500113 to Southwest Fisheries Science 

 Center, La Jolla, CA 92038, 72 p. Website: http://www. 

 cascadiaresearch.org/reports/rep-NPAC.pdf. [Accessed on 

 19 April 1999.] 



