Biology of the harlequin fish Othos dentex (Serranidae), with particular emphasis on sexual pattern and other reproductive characteristics. Issue 1 (January 2014)

• Record Type: Journal Article
• Authors: French, B.; Potter, I. C.; Hesp, S. A.; Coulson, P. G.; Hall, N. G.
• Is Part Of: Journal of fish biology. Volume 84:Issue 1(2014)
• Page Start: 106
• Page End: 132
• Publication Date: 2014-01
• Subjects: Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.12258
• Languages: English
• ISSNs: 0022-1112

Abstract

<abstract abstract-type="main" id="jfb12258-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="jfb12258-para-0001">Key biological characteristics of the harlequin fish <italic>Othos dentex</italic>, a representative of a monospecific genus of the Anthiinae (Serranidae), were determined from samples collected around reefs on the south coast of Western Australia. The females of this relatively long‐lived species (maximum recorded age in this study = 37 years) attained only a slightly greater maximum total length and age than males and neither the length nor the age‐frequency distributions showed a conspicuous sex‐based bimodality. Furthermore, gonads from a wide size and age range of <italic>O. dentex</italic> were shown by histology, at several locations along their length, to always comprise exclusively either ovarian or testicular tissues. Thus, <italic>O. dentex</italic> is a gonochorist, a sexual pattern only previously recorded definitively for one other anthiine serranid, <italic>i.e. Epinephelides armatus</italic>, which also occurs in south‐western Australia. Similar to <italic>E. armatus</italic>, <italic>O. dentex</italic> possesses 'solid' testes with a central sperm duct, thereby differing in structure from those typically found in serranids, in which there is a central membrane‐bound 'ovarian' lumen and peripherally located sperm sinuses. The gonadal characteristics and sexual pattern of these two gonochoristic anthiines are not consistent with a recent proposal for the trends exhibited by the evolution of gonochorism and protogyny within the Serranidae. <italic>Othos dentex</italic> has indeterminate fecundity and a protracted spawning period (7 months) and, on the basis of underwater observations and a low gonado‐somatic index (<italic>I</italic><sub>G</sub>) for males, is a pair spawner, which is unusual for a gonochorist of a serranid or member of a related family. While the large spots on the lower half of the body of <italic>O. dentex</italic> are shown quantitatively to be similarly yellow in juveniles and adult females, they then become blue in males at maturity and this intensifies during the spawning period, when they presumably play an important role in agonistic interactions among males and courtship with females. The attainment of maturity and rapid growth by <italic>O. dentex</italic> early in life may reflect selection pressures to reduce predation mortality during that period. Total mortality in the population is moderately low during later life, implying that the current fishing pressure on <italic>O. dentex</italic> is relatively light.</p> </abstract>