IMPACTS ON EAST COAST FISH STOCKS: LONG-TERM CLIMATE AND BENTHIC HABITAT CHANGES

Scientific interest in deep-sea coral recently expanded since it was discovered that they, like their shallow water counterparts, record the characteristics of their living environment. In some cases a yearly climate record for the lifetime of the coral, up to hundreds even thousands of years. However corals are restricted to certain environmental parameters and may not be representative of an entire region. More traditional proxies such as benthic foraminifera can be interpreted throughout sediment cores and used as lower resolution climate indicators. The discovery of deep sea coral on the Scotian Margin has renewed interest in a number of sediment cores within shelf basins where a thick, relatively high resolution Holocene sedimentary record is well preserved.

The present study provides detailed down core foraminiferal information for a number of Shelf basin cores. Interpreted paleoclimate events and trends throughout the Holocene will later be compared to the higher resolution deep-sea coral climate records. This will establish whether or not the corals are reflective of some long-term records that have been reported. The coral may also provide a strong chronology constraint for events that are coincident between the two records (foram and coral). This could result in the coral record being expanded much farther than its local occurrence.

As a result of examining foraminifera both on the coral and in the sediment, foraminiferal assemblages where Discanomalina semipunctata were found, have the potential of being a presence/absence indicator of deep sea coral on the Scotian Margin. This could also be applied down core using paleo-assemblages to note paleo-deep sea coral occurrences. It has become clear in recent Scotian Margin cruises that deep-sea coral provide fish habitat, and these foraminifera could also indicate paleo-fish habitat.

Results of this study will have important implications, strengthening our understanding of paleoclimate on the Scotian Margin, with the foraminiferal records supplying broader long-term trends and highly detailed deep-sea coral records detecting short-term variations such as the North Atlantic Oscillation over an extended period.