Body size at sexual maturity in the eteline snappers Etelis carbunculus and Pristipomoides sieboldii: subregional comparisons between the main and north-western Hawaiian Islands

摘要

New estimates of median body length at sexual maturity (L-50) are presented for females of ehu (Etelis carbunculus) and kalekale (Pristipomoides sieboldii) in the main Hawaiian Islands (MHI); these are compared with published estimates for females of each species in the north-western Hawaiian Islands (NWHI). This case study illustrates the general importance of identifying regional and subregional variations in species' life histories when estimating parameters for input to stock assessments. L-50 values differed somewhat between the two species, but greatly between the MHI and NWHI for each species. Size-standardised ovary weights were greater in the NWHI v. MHI for all-sized fish of both species and nominally greater at larger body sizes among the mature females of both species in the MHI compared with the NWHI. L-50 was smaller in the MHI compared with NWHI for females of both species. The mean (+/- s.e.m.) L-50 for female ehu was 23.4 +/- 0.3-v. 27.2 +/- 1.0-cm fork length (FL) in the MHI v. NWHI respectively. For female kalekale, the respective estimates were 23.8 +/- 0.3 and 28.6 +/- 0.7 cm FL. Possible determinants of these subregional geographic variations in L-50, including latitude, productivity and history of extraction by Hawaiian bottomfish fisheries, are discussed.