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In distinct contrast to the restricted movements of coastal stocks of lobsters (Homarus americanus), those inhabiting the outer continental shelf undertake extensive seasonal migrations. Of 5710 tagged lobsters released on the outer continental shelf off New England from April 1968 to June 1969, 400 had been recaptured by April 1970. The distribution of the recoveries demonstrated shoalward migration in spring and summer and a return to the edge of the shelf in fall and winter. Deep-sea lobsters have a faster rate of growth than coastal lobsters; growth increments at molting and the frequency of molting are greater.

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Sea pens, particularly Pennatula aculeata Danielssen, are major components of the megafauna in the Gulf of Maine, USA. A review of three separate collections (National Marine Fisheries Service, Woods Hole; University of Maine; Smithsonian Institution), as well as recent submersible and remotely operated vehicle survey work, have shown that this single species is fairly ubiquitous. It is, however, more prevalent in the eastern part of the Gulf and is almost absent from Wilkinson Basin in the west. The spatial distribution of sea pens was photographically documented on four submersible dive transects in the eastern and central Gulf of Maine in 1983. The degree of contagion of sea pen populations was evaluated using the variance-to-mean ratio and Morisita's index of dispersion. In all cases these indices were > 1, suggesting a contagious distribution. Both Poisson and negative binomial probability distributions were fitted to the data. The negative binomial was the best descriptor of the distributions on three transects. On one transect, neither distributional model had a significant fit at the 5% level. The effect of quadrat size on these distributions was assessed for three quadrat sizes (7, 3, and 1.24m2). The pattern for the smallest quadrat size showed a significant fit to both Poisson and negative binomial distributions, while the Poisson distribution did not fit the data for the larger quadrats. The density of sea pens in individual photographs varied from 0 to 8 m-2 in Georges Basin, but density estimates were slightly confounded by the ability of sea pens to withdraw into their burrows, completely below the sediment surface. Behavioral observations in situ on Jeffreys Bank in 1986 were made using a manned submersible to observe the withdrawal and extension of specified sea pens. Seventeen sea pens were monitored on five dives over 24 h; two specimens withdrew completely, and another individual extended from a fully withdrawn position. During the observation period, 88% of the sea pens remained fully extended.

SynopsisDuring 22 daylight submersible dives in August 1979 numerous juvenile and adult tilefish, Lopholatilus chamaeleonticeps, were observed in and around vertical burrows in the clay substrate of portions of Hudson submarine canyon in depths from 1 lo-230 m. The size and shape of the burrows varied considerably with the smallest juveniles occupying simple vertical shafts in the substrate. Larger fish were found in much larger burrows (up to &5 m in diameter and at least 2-3 m deep) that were funnel shaped in cross-section with the upper conical portions containing numerous smaller burrows of associated crabs. The range of burrow sizes observed suggests a regular sequence of burrow construction by tiletisih and the associated crabs. Both juvenile and adult tilefish swam into the burrows head first and exited tail first. This behavior, which would preclude the possibility of ambushing prey, and evidence of predation by sharks and other tiletish, suggests that the burrow is a refuge from predators.