ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on February 24, 2009
ICES Journal of Marine Science: Journal du Conseil 2009 66(6):1007-1014; doi:10.1093/icesjms/fsp016
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This article appears in the following ICES Journal of Marine Science issue: The Ecosystem Approach with Fisheries Acoustics and Complementary Technologies [View the issue table of contents]
Localization of individual mulloway (Argyrosomus japonicus) within a spawning aggregation and their behaviour throughout a diel spawning period
1 Centre for Marine Science and Technology, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
2 Department of Fisheries, Government of Western Australia, PO Box 20, North Beach, WA 6020, Australia
Correspondence to M. J. Parsons: tel: +61 8 9266 7225; fax: +61 8 9266 4799; e-mail: m.parsons{at}cmst.curtin.edu.au
Parsons, M. J., McCauley, R. D., Mackie, M. C., Siwabessy, P., and Duncan, A. J. 2009. Localization of individual mulloway (Argyrosomus japonicus) within a spawning aggregation and their behaviour throughout a diel spawning period. – ICES Journal of Marine Science, 66: 1007–1014.Mulloway (Argyrosomus japonicus) are a soniferous member of the Sciaenidae. During summer in the Swan River of Western Australia, individuals form spawning aggregations in turbid waters around high tide, during late afternoon and early evening. Mulloway produce pulsed vocalizations that are characteristic of the species and to an extent of individuals. Crepuscular passive acoustic recordings of vocalizing mulloway were collected from a four-hydrophone array during March 2008. Arrival-time differences proved the most robust technique for localization. Corroboration of fish position was observed in relative energy levels of calls, surface-reflected path differences, and relative range of successive calls by individuals. Discrete vocal characteristics of the tone-burst frequency and sound-pressure levels assisted the determination of caller identification. Calibration signals were located within a mean distance of 3.4 m. Three-dimensional locations, together with error estimates, were produced for 213 calls during a sample 4-min period in which 495 calls were audible. Examples are given of the movement and related errors for several fish successfully tracked from their vocalizations. Localization confirmed variations in calling rates by individuals, calling altitudes, and the propensity to vary call structure significantly over short periods, hitherto unreported in this species.
Keywords: fish sounds, localization, passive acoustics, spawning
Received 31 July 2008; accepted 9 November 2008; advance access publication 24 February 2009.