The life‐history ofCheilodactylus rubrolabiatusfrom south‐western Australia and comparison of biological characteristics of the Cheilodactylidae and Latridae: support for an amalgamation of families

Abstract

Cheilodactylus rubrolabiatus collected from the south and lower west coasts of Western Australia were used to investigate the influence of habitat and environmental conditions on the biology of this species. A lack of difference in the growth C. rubrolabiatus from cool south coast and warmer lower west coast waters in Western Australia and the greater maximum ages attained by fish on the latter coast, both run contrary to premises of the metabolic theory of ecology (MTE). Although the greater size (L50) and age (A50) at maturity of C. rubrolabiatus on the south coast is consistent with MTE, this may reflect higher densities of fish on discontinuous shoreline rocky reefs on this coast and thus the need for fish, particularly males, to attain a larger size to successfully defend habitat and mates during spawning. Members of the closely related Cheiodactylidae and Latridae vary in maximum fork length (LFmax 280–950 mm) and age (19–97 years) and display a range of growth patterns. While the L50 of cheilodactylid and latrid species increased with increasing asymptotic lengths (L∞), their maximum ages did not necessary reflect the A50 (i.e., mature early, but live long). The M (natural mortality): k (von Bertalanffy growth parameter) ratios indicate that Cheilodactylus and Nemadactylus species exhibit a type II life‐history strategy, typified by initial rapid growth, L50 close to their L∞ and little or no growth during an extended adult phase. A lack of distinct difference in the biological characteristics of the Cheilodactylidae and latrids may assist in resolving uncertainty regarding the taxonomy of these families.

The life history characteristics of Neosebastes pandus and the relationship between sexually dimorphic growth and reproductive strategy among Scorpaeniformes

“…It is therefore proposed that it is not until after the second winter of life that the first discrete opaque zone becomes visible in the otoliths of N. pandus when the fish are ~12–15 months old. The formation of the first opaque zone in the second winter of life by N. pandus parallels that for other fish species in south‐western Australia, such as Arripis georgianus (Valenciennes 1831), Achoerodus gouldii (Richardson 1843), Nemadactylus valenciennesi (Whitley 1937), Scorpis aequipinnis Richardson 1848 and Cheilodactylus rubrolabiatus Allen & Heemstra 1976, who all exhibit spawning periods between early autumn and late winter (Coulson, 2019; Coulson et al ., 2009, 2010, 2012; Fairclough et al ., 2000a, 2000b).…”

“…The short, 3‐month, late autumn to mid‐winter spawning period exhibited by N. pandus is identical to that for Scorpis aequipinnis in southern Western Australia and overlaps with other fish species from this region such as Sillaginodes punctatus (Cuvier 1829), A. gouldii , N. valenciennesi , C. rubrolabiatus , A. georgianus and C. gerrardi (Günther 1887) (Coulson, 2019; Coulson et al ., 2009, 2010, 2012, 2019; Fairclough et al ., 2000a; Hyndes et al ., 1998). Gonadal recrudescence in N. pandus , as in S. aequipinnis and A. georgiana , is initiated when day length is declining and water temperature starts to decline (see Figure 1 in Coulson et al ., 2012).…”

“…The otoliths of all three fish (185–213 mm) caught in September (early spring) with two opaque zones also possessed an opaque margin. As the spawning period for N. pandus is from May (late autumn) to July (mid‐winter), when opaque zones are typically starting to form, or have formed, respectively, in the otoliths of fish species in south‐western Australia ( e.g ., Coulson, 2019; Coulson et al ., 2010), it is presumed that the first opaque zone in the otoliths of N. pandus does not form until the second winter of life when the fish are ~12–15 months of age. It would thus follow that the smallest fish caught in January, May and June with a single opaque zone in their otoliths are ~21, 25 and 26 months old and those with two opaque zones caught in May, June and September are ~36, 37 and 42 months old.…”

“…The log‐likelihood, λ , for each curve, ignoring constants, was calculated as λ = (− n /2) ln( ss / n ), where n is sample size, ss refers to the sum of the squared residuals between the observed and expected L T values at age and ln represents the natural logarithm. When comparing the vBGCs, the percentage difference between the L T values at age, as determined by those curves, was also used as an indication of whether any significant difference was of significant biological difference, with a difference between L T values at age of <5% being considered of limited biological significance (Coulson, 2019; Coulson et al ., 2010).…”

“…The sex of all N. pandus were identified macroscopically, except for one fish from the west coast whose gonads were removed during filleting. As the reproductive data for N. pandus from neither the west nor south coasts encompass all months of the year, and the differences between the spawning periods of fish species on the lower west coast and south coasts exhibit little, if any, differences ( e.g ., Coulson, 2019; Coulson et al ., 2010), the data from both coasts were combined to determine the spawning period, and lengths and ages at maturity of females and males.…”