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Biological characteristics of three co-occurring species of armorhead from different genera vary markedly from previous results for the Pentacerotidae

Coulson, P.G., Hall, N.G. and Potter, I.C. (2016) Biological characteristics of three co-occurring species of armorhead from different genera vary markedly from previous results for the Pentacerotidae. Journal of Fish Biology, 89 (2). pp. 1393-1418.

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Biological characteristics of Pentaceropsis recurvirostris, Paristiopterus gallipavo and Parazanclistius hutchinsi were determined from commercial gillnet samples from temperate south-western Australian coastal waters. Growth zones in otoliths, with more than a few such zones, were readily detectable only after the otoliths had been sectioned. Visual analyses and modelling of the trends in marginal increments on sectioned otoliths demonstrate that these opaque zones are formed annually. Maximum ages of 55, 36 and 49 years, derived for P. recurvirostris, P. gallipavo and P. hutchinsi, respectively, reflect relatively low mortalities. These longevities greatly exceed those estimated, using otoliths, for Pentaceros wheeleri and Pentaceros richardsoni, which belong to the other pentacerotid subfamily. These differences may be due to the counts of ‘daily’ growth zones in sectioned otoliths of P. wheeleri not representing the complete age range of that species and the zones detected in whole otoliths of P. richardsoni not constituting the complete range of annually-formed zones. Pentaceropsis recurvirostris, P. gallipavo and P. hutchinsi recruited into the fishery in the sampling area as 2–3 year-old fishes. Pentaceropsis recurvirostris and P. hutchinsi exhibited little or no subsequent growth throughout the remainder of their protracted life, whereas, P. gallipavo continued to grow for c. 5 years and then underwent little further growth. Spawning of P. recurvirostris and P. hutchinsi peaked in the austral winter and autumn, respectively, but in the austral spring and summer with P. gallipavo, which is more typical of temperate species. Although the females of P. gallipavo and P. hutchinsi were mature, this did not apply to a few P. recurvirostris, some of which were >20 years old, implying that any given female of this species does not always spawn every year. Ovarian mass greatly exceeded testis mass, indicative of pair spawning, which is consistent with field observations. In contrast to P. recurvirostris and P. hutchinsi, the sex ratio was heavily biased towards males and the spawning period longer in P. gallipavo, suggesting that selection pressures for spawning success were greater for this latter species.

Item Type: Journal Article
Murdoch Affiliation(s): Centre for Fish and Fisheries Research
School of Veterinary and Life Sciences
Publisher: Blackwell Publishing Inc
Copyright: © 2016 The Fisheries Society of the British Isles
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