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Results
Overall

Lobsters were found at 8 of the 18 study sites (Figure 2). The size of rocks under which lobsters were found averaged 40 by 29 by 16 cm (Table 2), roughly 1.5 by 1.0 by 0.5 feet. The depth of standing water under these rocks ranged from 0 to 20 cm (Table 2).

Table 2. Dimensions of rocks sheltering lobsters and depth of standing water under the rocks at The Lobster Conservancy's intertidal study sites, Penobscot Bay Lobster Collaborative, 1998 and 1999 (n = 228).
Measurement
Mean
(cm)
Std. Dev.
(cm)
Minimum
(cm)
Maximum
(cm)
Rock length
40.2
17.85
7.6
121.9
Rock width
28.7
12.77
2.5
91.4
Rock height
15.8
8.06
2.5
50.8
Pool depth
5.8
3.82
0.0
20.0

Carapace length (CL) of lobsters ranged from 6 to 90 mm, with a mean of 38.5 ± 12.3 mm (n = 335; Figure 3). Two modal size class distributions were found (Figure 3). The smaller size class, measuring between 6 and 15 mm CL, represents young-of-the year (Cowan 1999a).

Sex ratio was skewed heavily toward males, with a sex ratio of nearly 2:1 male:female (chi-square test p <0.001; Figure 4). The incidence of injury was measured as claw loss; one-quarter of lobsters were missing one or both claws (Figure 5).

Molting is a continual process, which consists of preparing for, undergoing and recovering from ecdysis (the shedding of the shell). Lobsters that are just about to shed have dark-red flesh and limb buds, and very dark shells. Lobsters that have recently gone through ecdysis have soft shells, which then become brittle before hardening completely. In this study, the majority of lobsters had hard shells, indicating that molting had not occurred recently. Recently molted lobsters, i.e., with soft or brittle shells, were first detected in June (Figure 6). The peak molting period occurred in August, then decreased gradually (Figure 6).