The algal assemblage discovered at Ammen Rock Pinnacle is 

 one of the deepest in the world for a cold water habitat and 

 contains undescribed species. So far the research of Vadas and 

 Steneck indicate that primary production at great depth may be 

 higher than previously expected, and thus, offshore ledges may be 

 a trophic oasis in a relative nutrient desert. Manipulative 

 experiments (initiated in 1985) in which algae was transplanted 

 along a depth gradient, are beginning to yield the first 

 information of recruitment, survivorship, growth and primary 

 production in this type of habitat. Steneck and Vadas are now 

 focussing their attention on the processes of algal, settlement 

 and recruitment. Ian Davison and coworkers used reciprocal 

 transplants and laboratory studies in 1987 to demonstrate that 

 there are specific and possibly genetically fixed adaptations to 

 living in deep water. 



Witman and Sebens have quantified patterns of distribution 

 and abundance of benthic invertebrates along a depth gradient on 

 the same transect studied by Steneck and Vadas. Rates of 

 secondary, and tertiary (predators of sessile invertebrates) 

 production are being assessed by studying multiyear experiments. 

 Those experiments were designed to determine rates of 

 recruitment, growth, predation and survivorship along a depth 

 gradient from 30 to 75 m. Some of the abundant and commercially 

 important cod, pollock, cusk, haddock, and wolffish were observed 

 feeding on the bottom. Feeding rates and food selection of those 

 fishes have been studied using time- lapse movies and 

 manipulative studies. Aspects of fish predation are being 

 studied collaboratively with the team of Vadas and Steneck. A 

 new area of research initiated by Witman and Sebens in 1986 was 

 to examine the flow characteristics of water overlying their 

 study sites as potential mechanism for food transport for a 

 variety of sessile benthic invertebrates. 



The result of the combined studies of Vadas and Steneck and 

 Witman and Sebens is to determine the distribution and abundance 

 of rock dwelling organisms on offshore ledges and to establish 

 the nature of local food webs, energy flux, and carrying capacity 

 of these ecosystems as important components of the Gulf of 

 Maine. During the course of the project described above, 

 several significant discoveries were made. Some species such as 

 sea urchins, which are abundant in coastal habitats, are absent 

 at this site. Their absence and the rarity of decapods (crabs 

 and lobsters) may be due to predation on them by large, 

 commercially-important fishes. Other organisms such as certain 

 encrusting algae, crinoids and Metridium anemones are more 

 abundant than previously reported for coastal habitats in the 

 western North Atlantic. Possibly the most significant finds are 

 the kelp, sponge, and limpet species which have never-before been 

 reported for North America. Studies of chloroplast DNA indicate 

 that the kelp is an undescribed species. It is possible that 

 we have discovered a species assemblage unique to the central 

 Gulf of Maine. This is the only region in the Gulf where cold 

 "Maine Intermediate Water" contacts hard substrata within the 



