Journal of the Marine Biological Association of the UK



Research Article

Distributional and Biological Aspects of Copepods at Hydrothermal Vents on the Juan de Fuca Ridge, north-east Pacific ocean


Maia  Tsurumi a1c1, Ramona C.  de Graaf a2a3 and Verena  Tunnicliffe a4
a1 Institute of Ocean Sciences, PO Box 6000, Sidney, BC, V8L 4B2, Canada
a2 University of British Columbia, 6270 University Blvd., Vancouver, BC, V6T 1Z4 Canada
a3 The Bamfield Marine Sciences Centre, Bamfield, BC, V0R 1B0, Canada
a4 University of Victoria, PO Box 3020, Victoria, BC, V8W 3N5, Canada

Abstract

The abundance patterns of copepods on the Juan de Fuca Ridge was examined. One species was studied in detail. Twelve non-parasitic species are recorded from the Juan de Fuca, but only three dirivultid species and some unidentified harpacticoids are abundant in collections. Densities are estimated at 0·5 copepod cm−2 on vestimentiferan tubes to over 8 cm−2 on chimney surfaces. Aphotopontius forcipatus is most abundant at new vents and Benthoxynus spiculifer is most abundant at mature vents. Vents with reduced or undetectable fluid flow have higher diversity of copepod fauna. The life cycle of the siphonostome Stygiopontius quadrispinosus begins with a centrolecithal egg brooded singly or doubly on the female. Hatching and naupliar stages are unknown in benthic samples. The preadult stage (copepodite V) recruits to the vent habitat. Pre-adult males attach to pre-adult females and fertilize at the final copepodite VI moult. As the sex ratio is highly skewed in favour of females, males probably inseminate many females and there may be mate competition in populations where males are rare. Reproduction is probably continuous or semi-continuous. Abundance is greatest on sulphide edifices near the points of hot water egress. This copepod co-occurs with the alvinellid polychaete Paralvinella sulfincola.

(Received April 12 2002)
(Accepted March 10 2003)


Correspondence:
c1 e-mail: tsurumim@pac.dfo-mpo.gc.ca