Spatial ecology and conservation of deep-sea fishes and corals off Newfoundland and Labrador, Canada

Baker, Krista D. (2013) Spatial ecology and conservation of deep-sea fishes and corals off Newfoundland and Labrador, Canada. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Ongoing deep-sea fisheries off Newfoundland and Labrador, Canada since the late 1960s have resulted in large population declines of both targeted and non-targeted species. The lack of in situ observations from deep waters in this region limit our understanding of the factors influencing distributions of vulnerable taxa such as corals and fish, and the links between them. I analyzed data from a research cruise that used a remotely operated vehicle to explore 105 km of seafloor, spanning a depth range of 351 - 2245 m, in three canyons off Newfoundland and Labrador in 2007. I observed over 160,000 coral colonies, comprising 28 species, and over 18,000 individual fishes, comprising at least 74 species. Distinct assemblages of deep-sea corals and fishes were found based on habitat type (or bottom type) and depth. Keratoisis grayi was more likely to be broken, dead or partially dead, and less abundant in trawled areas. Multiple factors predicted grenadier abundance and/or presence, but these varied in importance with sampling resolution. Using life table analyses, I predict prolonged recovery rates for two deep-sea fishes: Coryphaenoides rupestris and Macrourus berg/ax. These findings illustrate that deep-sea corals influence the distribution and abundance of fishes, that trawling negatively affects long-lived deep-sea corals in this region, that deep-sea fishes will recover slowly (if at all) from documented declines, and that many unknowns remain regarding the sustainability of this ecosystem. Nonetheless, these findings can help to support deep-sea conservation efforts off Newfoundland and Labrador.

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