Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Journey Into Midnight: Faunal Composition and Vertical Distribution of Whalefishes and Their Allies in the Bathypelagic Gulf of Mexico

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Gulf of Mexico Oil Spill and Ecosystem Science Conference / Tampa Bay, Florida

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Despite comprising the largest biome on Earth, the bathypelagic zone and its inhabitants represent a “black hole” in our understanding of the deep ocean and its functioning. Physical and monetary limitations have resulted in large knowledge gaps regarding deep-pelagic ecosystems. The global bathypelagic realm is characterized by high pressure, low temperature, an absence of sunlight, and low food availability. These features create a limiting environment only inhabitable by specially adapted groups of fishes. Whalefishes (Cetomimidae, Barbourisiidae, and Rondeletiidae) are a taxonomically and systematically challenging group of deep-sea fishes that are considered solely bathypelagic; however, assemblage and vertical distribution data on these taxa are lacking, globally and in the Gulf of Mexico (GoM). The DEEPEND Consortium and ONSAP project have collected whalefish specimens from the GoM utilizing various net types, including a high-speed rope trawl and a multiple-opening-and-closing net system. The variance in gear type allowed for the collection of larger female specimens and smaller male, juvenile, and larval specimens. Project aims of this study are to (1) describe and (2) analyze the faunal composition (i.e., species diversity, sex, life-history stage) of the GoM assemblage, and (3) determine the vertical distribution of each species and life stage. We will present: percent frequency of occurrence for each species, comparisons between specimen standard length (SL) and gear type, length-weight regressions by species, sex ratios by species, difference in time of day catches per species, and comparisons of capture depth with species and SL. This study will significantly increase the fundamental knowledge of the taxon, as only 770 whalefish records exist worldwide. We have 520 specimens in our collection from the GoM.

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