Abyssal scavenging demersal fauna at two areas of contrasting productivity on the Subantarctic Crozet Plateau, southern Indian Ocean

N. J. Cousins, T. Horton*, B. D. Wigham, P. M. Bagley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The Crozet Plateau is situated below typical high-nutrient, low-chlorophyll (HNLC) waters of the southern Indian Ocean. The area to the east of the Crozet Islands experiences high levels of surface productivity during the austral summer due to natural iron enrichment from terrestrial sources and favourable light conditions. The demersal scavenging fauna at two areas of contrasting productivity, to the east and south of the islands, were investigated using two landers equipped with baited cameras and traps. Five species of scavenging fish were observed along with five groups of invertebrates during a single deployment of the RObust BIOdiversity (ROBIO) lander. Further deployments of the Fish RESPirometry (FRESP) video lander yielded no additional scavenging fish species. A modelled arrival and departure curve for the abyssal grenadier Coryphaenoides armatus suggests a region of low food availability compared to other regions worldwide. The ROBIO-derived abundance estimate for C. armatus of 187 ind. km(-2) is comparable with published trawl-derived estimates. Significantly more amphipods were collected to the south of the islands, which was subject to lower organic matter supply. Reasons for this are unknown but may be due to differing current direction/velocities, or increased fish predation at the enriched site. The numerically dominant amphipod species present was Paralicella caperesca, followed by Eurythenes gryllus and Orchomenella gerulicorbis. A further five species were observed in low numbers, some occurring only once. One, Paracallisoma sp. nov, was a new species.

Original languageEnglish
Pages (from-to)299-306
Number of pages8
JournalAfrican Journal of Marine Science
Volume35
Issue number2
DOIs
Publication statusPublished - 12 Aug 2013

Bibliographical note

We would like to thank the officers, crew and shipboard party of the benthic Crozet cruise (D300), RRS Discovery, for assisting with gear deployment. The benthic Crozet cruise (NER/S/A/2003/00573) and NJC (NER/S/A/2003/11190) were funded by the UK Natural Environment Research Council (NERC). Thanks are due to Prof. IG Priede and Dr AJ Jamieson of Oceanlab, University of Aberdeen, and two anonymous reviewers for their comments on earlier versions of the manuscript.

Keywords

  • amphipods
  • Crozet Islands
  • deep water
  • marine fish
  • scavengers
  • deep-sea fish
  • Arabian Sea
  • in-situ
  • necrophagous amphipods
  • coryphaenoides-armatus
  • baited landers
  • Atlantic-Ocean
  • North Pacific
  • assemblages
  • consumption

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