Publication Date

Fall 2017

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Moss Landing Marine Laboratories

Advisor

Scott Hamilton

Keywords

Deep sea, Fisheries, Indian Ocean, Life History, Shark, Taxonomy

Subject Areas

Ecology; Biology; Environmental science

Abstract

During the last quarter of a century, the conservation and management of chondrichthyans (collectively, sharks, rays, and chimaeras) has received considerable focus. This is especially true for deep-sea chondrichthyans. As technologically advanced fisheries expand into deeper waters of the high seas, new chondrichthyan species are being discovered and described at an increasing rate. The objectives of this study were to investigate the deep-sea chondricthyan fauna in a remote region of the Southwestern Indian Ocean Offshore and provide descriptions of three species of Chimaeridae previously unknown to science, and collect and analyze biological parameters relating to the life histories of all shark species encountered. Specimens were collected as bycatch in deep-sea fisheries from 46 sites along deepwater seamounts of the Southwest Indian Ocean Ridge and the Madagascar Ridge. Among the species encountered were three relatively large chimaeroids which, upon closer examination, were determined to be distinct from all other known members of the family. A description these three new species is presented. A total of 4009 specimens were examined and sex ratios, size range, smallest mature, largest immature, and length at 50% maturity (LT50) calculated. Detailed information is presented on the reproductive biology, life history, and distribution of 31 species representing 14 genera

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