On the life history of the lesser gurnard (Scorpaeniformes: Triglidae) inhabiting the Agulhas Bank, South Africa

Abstract

Growth analysis based on sectioned sagittal otoliths revealed the lesser gurnard Chelidonichthys queketti on the Agulhas Bank to be relatively fast growing and long lived, with ages of up to 7 years being recorded. Total length at age (mm) was described best by the specialized von Bertalanffy growth model as L =306·1 (1 - e ). First approximations of total, natural and fishing mortality rates were determined at 0·73, 0·38 and 0·35 year respectively. The adult population was male dominated with a sex ratio of 1 female: 1·2 males with the mean size of males and females being similar. The lesser gurnard is an iteroparous species with females maturing by the end of the first year of life (195 mm L ), thereafter spawning throughout the year with reproductive activity peaking over spring and late summer. The lesser gurnard appears to exhibit similar life-history patterns to other triglid species in that it can be classified as a generalist. Generalistic life-history characteristics such as a fast growth rate, early sexual maturity at a relatively large size, a non-seasonal spawning pattern, feeding on a variety of prey organisms and the ability to inhabit various substrata could all contribute to it maintaining a high biomass on the Agulhas Bank.

Effect of habitat selection on the dietary patterns of two triglid species

“…Aspects of the biology of triglids suggest that they have a generalistic and opportunistic life-history character. Limited available studies regarding habitat preferences report that they are found over a variety of soft sedirnents such as mud, sand and low-profile reef with interspersed mud and sand depressions (Ross 1977, Papaconstantinou 1983, Booth 1997). The few studies on feeding bi.ology in the family suggest that the species studied are opportunistic, feeding on a wide range of available epibenthic and infaunal invertebrates (Ross 1977, Caragitsou & Papaconstantinou 1990, Meyer & Smale 1991, Colloca et al 1994.…”

Life history of the <i>Pomadasys incisus</i> (Osteichthyes: Haemulidae) of the Canarian Archipelago

“…Typical life history characteristics include large body size, delayed age at sexual maturity, a long life and a low natural mortality (Booth, 1997). In contrast, a generalist has a life history strategy that tends towards the oportunistic use of the resources.…”

“…In contrast, a generalist has a life history strategy that tends towards the oportunistic use of the resources. Therefore, generalists exhibit early maturity, fast growth rate, small body size, and high natural rnortality (Booth, 1997). To understand where f) incisus fits into this life history classification continuurn, vanous life history parameters such as maximum length, maximum age, growth rate, size and age at maturity rnust be analysd together.…”

Age estimation and growth pattern of the island grouper, <em>Mycteroperca fusca</em> (Serranidae) in an island population on the northwest coast of Africa

“…the three models of growth explain over 97% of the growth pattern, as shown by the determination coefficients for each curve. the use of the von Bertalanffy model has been criticised on various accounts (Booth, 1997), such as the use of parameters of scarce biological significance (schnute, 1981), or the absence of parameters which bear in mind seasonal variations in the growth rate (Pauly, 1980;Moreau, 1987). nevertheless, von Bertalanffy's model was chosen for a more exhaustive study of the growth of the grouper, since it affords a simple model with a smaller number of parameters than other models, but allows comparison between species and groups of species.…”