ECOLOGY OF BUZZARDS BAY: An Estuanne Profile 75 



The osprey (Pandion haliaetus) is considered 

 a rare bird whose numbers diminished throughout 

 the United States during the 1 950"s and 1 960's as 

 a result of the widespread use of the pesticide DDT. 

 The pesticide primarily affected ospreys by causing 

 a thinning of the eggshell, rendering the eggs fragile 

 and susceptible to disturbance or predation. Ospreys 

 nest high above the ground, building large nests up 

 to 2.4 m in diameter usually in large dead trees near 

 the water, which provide them with easy access to 

 their primary diet offish. Human activities and de- 

 velopment along the coast have resulted in the dis- 

 appearance of many of these potential nesting plat- 

 forms. Efforts all around Buzzards Bay to erect poles 

 with nesting platforms have resulted in the return of 

 many ospreys to the bay shores (Poole 1 989). 



A nonavian endangered species under federal 

 protection is the Plymouth red-bellied turtle 

 (Pseudemys rubiventris bangsi), a subspecies of 

 the red-bellied turtle of mid- Atlantic coastal plains. 

 Only about 200 adults making up 1 2 populations 

 are currently known, all within Plymouth County, 

 which extends into the northeastern portion of the 

 bay's watershed. Primarily a herbivorous freshwa- 

 ter reptile inhabiting freshwater ponds, the Plymouth 

 red-bellied turtle requires a sandy substrate in the 

 surrounding upland for nesting in late June and early 

 July. Hatchlings emerge from late August through 

 October, and survivors reach maturity at 8 to 15 

 years, females possibly later than males. While many 

 factors have led to the decline of the Plymouth red- 

 bellied turtle, possibly the most significant has been 

 habitat losses both by direct destruction or indirect 

 alteration resulting from land-use practices that pre- 

 vent upland burning and decrease the availability of 

 suitable nesting sites (Massachusetts Natural Heri- 

 tage Program 1987). 



There are a few strictly marine threatened or 

 endangered species that use the bay; all are sea 

 turtles. Federally listed species that frequent Buz- 

 zards Bay waters are the loggerhead (Caretta 

 caretta, threatened), Kemp's ridley (Lepidochelys 



kempii, endangered), and leatherback 

 {Dermochelys coriacea, endangered). These sea 

 turtles visit the bay in summer after migrating from 

 overwintering regions in warmer southern waters. 

 Water temperature partially dictates their appear- 

 ance because they lack the ability to regulate body 

 temperature. Ridley and loggerhead turtles cannot 

 withstand temperatures below 23.2° C and 19.5° 

 C. respectively (O'Brien 1 990). while the leather- 

 back, which may have some thermoregulatory 

 mechanism, has been found in colder northern wa- 

 ters (D. Mignogno, personal communication). The 

 numbers of sea turtles frequenting Buzzards Bay 

 are difficult to ascertain since their subtidal distribu- 

 tion makes sightings rare; however, 14 leatherback 

 sea turtles were stranded around the bay from 1 984 

 to 1 987. Kemp's ridley sea turtle reports include 

 three standings in the early 1 900's and a large num- 

 ber of sitings and standings during a single event in 

 the 1 930's. Since the 1 930's there have been no 

 reports of further Kemp's ridley strandings (cf. 

 Payne et al. 1 994), although they have been occa- 

 sionally sighted (Prescott in Camp, Dresser, and 

 McKee, Inc. 1 990). Only a single loggerhead has 

 been found stranded in recent years ( 1 985) within 

 Buzzards Bay. 



Use of Buzzards Bay by sea turtles is likely 

 greater than suggested by the available sighting and 

 standing reports given the difficulty in seeing turtles 

 at sea and the restriction against net fishing within 

 the bay, which is a major source of sightings in other 

 regions (cf. Payne et al. 1 994). 



Buzzards Bay does not present a habitat for sig- 

 nificant utilization by either whales or dolphins. It 

 appears that the absence of topographic and 

 oceanographic features that concentrate prey spe- 

 cies (and possibly the bay's shallow waters) are the 

 underlying causes. A few individual sightings of ce- 

 taceans have been reported this century, though 

 they tend to be near the entrance to Buzzards Bay. 

 typically off Cuttyhunk. rather than within the bay 

 itself(Payneetal. 1994). 



