An investigation of the spawning behaviour of the chokka squid Loligoreynaudii and the potential effects of temperature using acoustic telemetry

Publication Type:Journal Article
Year of Publication:2010
Authors:N. J. Downey, Roberts, M. J., Baird, D.
Journal:Ices Journal of Marine Science
Volume:67
Pagination:231-243
Date Published:Mar
Type of Article:Article
ISBN Number:1054-3139
Accession Number:ISI:000274341200004
Keywords:acoustic telemetry, Africa, Behaviour, CAPE, Cephalopoda, DORBIGNY, environment, grounds, loliginidae, Loligo reynaudii, Myopsida, SOUTH-EAST COAST, spawning, squid, temperature, VULGARIS-REYNAUDII
Abstract:

Spawning aggregations of chokka squid are influenced by environmental conditions. Acoustic telemetry was used to monitor the behaviour of spawning squid in relation to environmental variability. During the November squid-fishery closed seasons of 2003 2006, hexagonal VR2 receiver arrays were moored on and around active spawning aggregations in Kromme Bay, South Africa. In all, 45 squid were tagged (V9P-6L-S256 transmitters) and released within these arrays. Three presence-absence behaviours were identified: (i) arrival on the spawning site at dawn and departure after dusk, (ii) continuous presence for a number of days, and (iii) presence interrupted by frequent but short periods of absence. Movement between spawning sites was both diurnal and nocturnal. Squid presence at the monitored sites increased after dawn and decreased towards and after dusk. Occasionally, a core aggregation of squid remained on the spawning sites at night. Temperature data at the sites indicated occasional upwelling, and although the role of temperature in the spawning process is not well understood, data suggest that it is linked to the continuation and or interruption of spawning after an aggregation has formed. The initial formation of spawning aggregations appears to be triggered by upwelling events.

Alternate Journal:ICES J. Mar. Sci.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith