Abstract.— significant changes 

 in the hiomass of sandlanee Amrno- 

 (Ij/tea spp. and in the abundance of 

 the copepod Calanus finniarchicus 

 in the southern Gulf of Maine co-oc- 

 curred with a shift in the occurrence 

 and abundance of four species of ba- 

 leen whales in the region. During the 

 years 1982-88 the abundance of 

 sandlanee was negatively correlated 

 to the abundance of C finniarchicus 

 (r, = -0.883, F<0.05). Peak years 

 of abundance for C. finmarchicus 

 during 1982-88 in the study area 

 were the lowest years of abundance 

 for sandlanee. The abundance of C. 

 finmarchicus and sandlanee was at 

 a regional maximum during 1986 

 and 1988, respectively. 



The abuniiance of humpljaek and 

 fin whales were marginally corre- 

 lated to each other (r, = 0.3338, P< 

 0.08). The abundance of humpbacks 

 was negatively correlated with right 

 whales (r, = -0.7753, P<0.001) and 

 sei whales (r,= -0.5507, P<0.01). 

 The patterns of occurrence for right 

 and sei whales were significantly re- 

 lated to each other (r, = 0.6842i P< 

 0.001). Right and sei whales were 

 common in the region only during 

 1986, when copepod abundance 

 reached a regional maximum and 

 sandlanee abundance a regional 

 minimum. These patterns of whale 

 occurrence reflect known prey pref- 

 erences, and are therefore expected 

 between the piseiverous humpback 

 and fin whales and the highly plank- 

 tiverous right and sei whales. 



We hypothesize that the spatial 

 distribution and abundance of baleen 

 whales in the Gulf of Maine can be 

 characterized as a series of ecological 

 responses to human-induced changes 

 in the abundance of planktiverous 

 finfish. 



Recent Fluctuations in the Abundance 

 of Baleen Whales in the Southern 

 Gulf of Maine in Relation to 

 Changes in Selected Prey 



p. Michael Payne 



Marine Mammal and Seabird Studies, Manomet Bird Observatory 

 Box 936. Manomet, Massachusetts 02345 



David l\i. Wiley 

 Sharon B. Young 



Plymouth Marine Mammal Research Center 

 P O Box 3313, Plymouth, Massachusetts 02361 



Sharon Pittman 

 Phillip J. Clapham 



Cetacean Research Program, Center for Coastal Studies 

 PO Box 1036, Provincetown, Massachusetts 02657 



Jack W. Jossi 



Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA 

 South Ferry Road, Narragansett, Rhode Island 02882 



During the mid-1970s, a dramatic in- 

 crease in the abundance of sandlanee 

 Amm-odytes spp.* precipitated a sig- 

 nificant change in the abundance and 

 composition of the ichthyofauna in 

 the shelf waters of the northeastern 

 United States (Smith et al. 1978, 

 1980; Morse 1982). The population 

 explosion of sandlanee coincided with 

 a 50% reduction in total finfish bio- 

 mass in the same region between 

 1968 and 1975 (Clark and Brown 

 1977). This decrease was primarily 

 due to the commercial depletion of 

 stocks of herring Clupea harengus 

 and mackerel Scomber scomhrus (An- 

 thony and Waring 1980, Grosslein et 

 al. 1980). A concurrent increase in 

 sandlanee abundance following the 

 depletion of North Sea herring and 

 mackerel stocks led Sherman et al. 

 (1981) to suggest that sandlanee had 

 taken over ecological niches previous- 



Manuscript accepted 3(1 May I'.tOO. 

 Fishery Bulletin. U.S. 88:687-696. 



• Two species of this genus, A. americanux and 

 .4. duhiii^, occur in the shelf waters of the 

 northeastern United States (Richards et al. 

 1963, Reay 1970. Richards and Kendall 1973, 

 Meyer et al. 1979, Richards 1982). 



ly occupied by these species in many 

 areas of the Northwest Atlantic. 



Since the mid-1970s sandlanee 

 have become increasingly important 

 in the Gulf of Maine as prey for com- 

 mercial fish (Bowman et al. 1984), 

 seabirds (Powers and Backus 1987), 

 pinnipeds (Payne and Selzer 1989). 

 and baleen whales (Overholtz and 

 Nicolas 1979, Hain et al. 1982, Payne 

 et al. 1986). Sandlanee were the only 

 confirmed prey of the humpback 

 whale Megaptera novaeangliae be- 

 tween 1975 and 1979 (Hain et al. 

 1982, Mayo 1982) and the only prey 

 significantly correlated with the dis- 

 tribution of humpbacks in the Gulf 

 of Maine between 1978 and 1982 

 (Payne et al. 1986). Also, fin whales 

 Biiliienoptera physalus, sympatric 

 with humpbacks in this region, have 

 frequently been observed exploiting 

 sandlanee (Overholtz and Nicolas 

 1979). 



Two other species of large baleen 

 whales, the northern right whale 

 Eubalaena glacialis and the sei whale 

 Balaenopfcro horealis. also occur in 



687 



