Predicting habitat for two species of deep-water coral on the Canadian Atlantic continental shelf and slope

Abstract

Documentation of hundreds of locations for Canadian deep-water corals has been obtained through scientific initiatives and local fishermen’s knowledge. Using these locations, as well as relevant oceanographic data, this study determined areas of suitable habitat for Paragorgia arborea and Primnoa resedaeformis along the Canadian Atlantic continental shelf and shelf break using predictive models. The study area included a band approximately 800 km long x 200 km wide from Cape Breton to the Gulf of Maine, and was chosen based on density of coral sites. Several environmental factors including slope, temperature, chlorophyll a, current speed and substrate may be important in determining suitable coral habitat and were included in the analysis. There are many different techniques used to model habitats, but frequently they are limited by the type of data available. Comparatively, few techniques using presence-only data are available. We utilized BioMapper, a program which uses Ecological Niche Factor Analysis (ENFA), to generate habitat suitability maps by relating data on species presence with background environmental data to determine the species’ niche. We found that habitat requirements differed between the two species of coral. For Paragorgia arborea, the niche was highly specialized, and characterized by steeply sloped environments and rocky substrate. In contrast, for Primnoa resedaeformis, suitable habitat was more broadly distributed in the study area, and located in areas with high current speed, rocky substrates and an approximate temperature range between 5 and 10°C. This is the first study to use predictive modelling to identify suitable habitat for deep-water coral, which may prove an important tool for the conservation of these organisms.