NURP Project Summary


	The Ecology of Deep Water Octocorals off the Northeast Coast of the United States (Year 3 of 3) Project Number: NAGL-02-06C Principle Investigators: Watling, L. E., P. J. Auster, and K. J. Eckelbarger Region(s): Georges Bank Submarine Canyons, Western Georges Basin

To most people, the concept of a deep water coral is an oxymoron. In fact, until the wide publicity about recent legislation banning trawling in deep coral beds off the coast of Norway, the existence of these species was known only to a handful of scientists and a large number of fishermen. In North America there is little knowledge of their existence in the minds of the general public as well as the broader scientific community. Along the American east coast deep water corals have been known since at least 1862 when scientific surveys noted the presence of Primnoa species on Georges Bank. Several other deep water coral species from depths greater than 200 fathoms off the coasts of New England and Nova Scotia were also documented during the latter part of the 19th century. Aging studies of corals such as Primnoa (and others from the octocoral group) have shown that colonies can be centuries old. As recently as the late 1960s, long-lived corals were described as common components of the gravel fauna of the Gulf of Maine. Submersible dives over the last fifteen years in many of the areas previously described as coral habitats has demonstrated their rarity. Given that the existence of these remarkable, and often beautiful, species has been known for more than a century, it is striking that we know almost nothing about their biology and the role they may play as habitat for vagile deep water fauna, including those species targeted in recent exploratory fisheries. This proposal has as its major objective the characterization of deep-water octocoral communities in the Gulf of Maine and the outer continental shelf of the northeastern United States. These coral areas have been known to generations of fishermen, principally as a result of gear damage or by-catch, first with long-liners and gill netters, and then with draggers. Because of the difficulty associated with studying these animals, scientists have only recently begun to understand their potential importance to benthic ecosystems, their rarity in the underwater landscape, and their sensitivity to human caused disturbances. For this project, an ROV will be used to determine if the gorgonian species of the nearshore Gulf of Maine are con-specific with the gorgonians from the outer continental shelf off Georges Bank, if gorgonian diversity is the same nearshore and offshore, if inshore gorgonians represent pseudopopulations of the offshore gorgonian populations, if size class distributions of inshore and offshore gorgonian populations are similar, and if gorgonian associates in both inshore and offshore areas are representative of the regional benthic fauna. The results of this work will form the basis for future protection of rare and potentially valuable corals that serve as habitat for a variety of other taxa and are seriously threatened by human activities (e.g., fishing gear, hydrocarbon extraction). Further, the collapse of demersal fish populations has focused attention on deep coral communities as critical habitat for some economically important species such as those of the genus Sebastes, as well as taxa that are of interest in deepwater exploratory fisheries (e.g., slimeheads - known as orange roughy from the species targeted off New Zealand and Australia). The results of this research will qualify, and begin to quantify the services that deep octocoral assemblages may provide to various life stages of economically (and potentially) important species of fish and invertebrates. Further, this study will characterize the habitats in which corals occur on the northeast continental shelf and slope. Such knowledge, combined with studies from other areas, will allow us to develop a plan to assess coral distribution and abundance on the outer continental shelf and upper slope within the U.S. EEZ.

An offshoot of this project was implemented during 2001 as a joint project with NOAA’s Ocean Exploration Office (DeepEast Project). The field component utilized the DSV ALVIN and focused on the deep regions of 3 canyons and two seamounts. However, due to Hurricane Emily, only two canyons were visited with ALVIN but a multibeam map of the summit of Bear Seamount was produced. The original scope of the NURC project was not implemented until 2002.

In 2002, the cruise was focused on the northern Gulf of Maine. Due to technical problems with the ROV, caused by fouling in fishing gear, only 2 days of diving were completed. Unused operational funds from this cruise were carried over for use in 2003. A proposal was submitted to the National Geographic Society’s Committee for Research and Exploration for additional funding in order to conduct 8 operations days at this site. The planned 2004 cruise will go to the Georges Bank submarine canyons, the northern slope of Georges Bank and other deep water areas of the Gulf of Maine. Operations will be conducted from the NOAA ship Ron Brown that was granted to NURC-NA&GL and the ROV’s Kraken and Hela will be on board for diving operations.