Cetaceans 



Most of the cetaceans discussed here range along the Maine coast from about 

 late April through October or early November. During the course of the year 

 many of them show a clear north-south migration pattern. The harbor porpoise 

 is an exception, exhibiting an onshore-offshore migration pattern. The major 

 abiotic factors that influence cetacean distribution are temperature, 

 currents, and physiography, but little detailed information is available. The 

 finback whale is the most common of the large whales to frequent coastal Maine 

 and presently the most abundant large whale in New England waters. The harbor 

 porpoise is the numerically dominant cetacean in the Gulf of Maine. A summary 

 of recorded sightings of marine mammals within the last few decades in the 

 characterization area is given in table 13-3. 



During early spring or winter, sightings of cetaceans are common in the 

 southern portion of the Gulf of Maine, Massachusetts Bay, and Cape Cod Bay. 

 Apparently, the animals migrate up the coast in spring and early summer, 

 remaining along the Maine and Fundy coasts until late autumn. This 

 distribution trend correlates well with the distribution of herring and other 

 schooling fishes, squid, and zooplankton (copepods and euphausiids) . During 

 this period species generally aggregate in productive areas, such as fishing 

 banks, river mouths, or estuaries. Large whales, such as the right whale and 

 humpback whale, sometimes approach the coast; however, most of the species 

 will be found in water between 20 and 50 fathoms (37 and 91 m) deep. Harbor 

 porpoises tend to be found in relatively shallow water (20 to 50 fathoms or 

 less). The 50-fathom contour appears to be an important demarcation of 

 feeding areas, as does the 100-fathom (183-m) contour farther offshore (Katona 

 1977). 



Over the past several years inshore movements of several species, including 

 humpback whales, appear to be on the increase in North Atlantic waters but it 

 is difficult to distinguish how much of the observed increase is due to an 

 increase in interested observers. The apparent movement inshore seems to be 

 in part due to the collapse of the capelin stocks on the Grand Banks as a 

 result of overfishing (Lien and Merdsoy 1979). The whales are probably moving 

 inshore in search of alternative food supplies. Gaskin and coworkers (l r 79) 

 conclude that the presence of humpbacks in the herring-rich area of the 

 approaches to Cobscook Bay and Passamaquoddy Bay is likely to be a regular and 

 annual event. Unfortunately, the increasing occurrence of humpbacks close to 

 shore increases the likelihood of their entanglement with fishing gear and 

 collisions with boats. 



It is important to remember that the large whales, at least, can easily travel 

 the entire Maine coast in a day or two if they choose to; consequently, their 

 feeding ranges may be the whole of the Gulf of Maine. Despite their mobility, 

 however, many individuals may remain in local areas for weeks or sometimes 

 months. Data gathered during the period 1973 to 1976 show that humpback 

 whales and finback whales regularly use the Mt. Desert Rock (region 5) region 

 for feeding from June through September. Humpback whales (with calves) spent 

 extended periods in the Campobello Island (region 6) region during July to 

 September, 1979 (Gaskin et al. 1979). 



13-6 



