To evaluate the contraction and extension behavior of sea 

 pens an experiment was conducted in 1986 using the submersible 

 Delta. Four lm^ quadrats were deployed from the surface ship in 

 an area of relatively high sea pen density on Jeffreys Bank and 

 in situ observations were made on the sea pens inside and immedi- 

 ately outside the quadrats. During a 24 hour period 17 sea pens 

 were monitored in a series of five dives. The presence of sea 

 pens, or absence after the first dive, was noted relative to 

 their position in the quadrats as well as their degree of 

 contraction into the substrate. In other words, individual sea 

 pen behavior was monitored over one 24 hour period. 



In addition to the behavior experiment, sea pens were col- 

 lected for laboratory observation. Animals were scooped up from 

 the bottom with the submersible ' s manipulator arm, placed in a 

 collecting bag along with their substrate and brought to the 

 surface where they were transferred to a tank of cooled seawater. 

 In the laboratory they were re-established in burrows, made in 

 the substrate collected at the sampling site, and maintained in a 

 refrigerated seawater system. The tanks themselves were darkened 

 and the water renewed every other day. 



RESULTS 



The National Marine Fisheries Service macrobenthic survey 

 sampled 62 stations in the Gulf of Maine region where sea pens of 

 the genus Pennatula were present. Material collected at eleven 

 of these stations were examined in more detail and the species of 

 pennatulid was identified as P. aculeata by Dr. F.M. Bayer. 

 These data are shown in Figure 1. (In the figure the specific 

 level of identification is indicated by an x). Observations on 

 sea pen distribution from submersibles and remotely operated 

 vehicles are shown in Figure 2. In this case, sea pens were 

 simply identified to the generic level, Pennatula , based on 

 photographs, video or direct observations. (The x in this figure 

 denotes the location of the site for behavior studies). 



Comparing both plots of sea pen distribution, which cover a 

 time span of 30 years, it is clear that this species has a more 

 or less ubiquitous distribution throughout the Gulf of Maine. A 

 notable absence is in Wilkinson and Murray Basins which are the 

 largest basins in the western Gulf. Neither database includes 

 observations of sea pens in this region, although two stations 

 where only four sea pens were collected fall within the 200 m 

 isobath that includes both Wilkinson and Murray Basins as well as 

 three other smaller basins in the western Gulf. In fact, one 

 submersible dive in 1985 was conducted in the deepest part of 

 Wilkinson Basin (42°45.21'N 69°49.48'W) specifically searching 

 for sea pens. A two and one half hour transect produced no 

 sitings. In 1987, remotely operated vehicle operations on the 

 western side of Wilkinson Basin also resulted in no sea pen 

 sitings, although these dives were not specifically searching for 

 Pennatula . 



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