Reproductive biology of female striped marlin Kajikia audax in the western Pacific Ocean
Journal
Journal of Fish Biology
Journal Volume
92
Journal Issue
1
Pages
105
Date Issued
2018-01-01
Author(s)
Abstract
© 2017 The Fisheries Society of the British Isles. Length and mass data for 1260 (536 females, 683 males, 41 sex unknown) striped marlin Kajikia audax were collected at the fish markets of Tungkang, Singkang and Nanfangao from July 2004 to September 2010. Of these samples, 534 gonads (236 females and 298 males) ranging from 95 to 206 cm in eye-to-fork length (L EF ) and 8 to 88 kg in round mass (M R ), were collected. Chi-square tests indicated sex ratios were homogeneous among months in 2004 and 2006–2008, but not in 2005, 2009 and 2010; and there were significant differences in sex ratio by size. The overall sex ratio (R S ) differed significantly from the expected 0·5. Kajikia audax are sexually dimorphic and the proportions of females increased with size between 140 and 210 cm L EF . Reproductive activity was assessed using a gonado-somatic index (I G ), external appearance of the gonads and histological examination and results indicated that the spawning season occurred from April to August with a peak in June to July. Based on histological observations and the distribution of oocyte diameters, K. audax are multiple spawners and their oocytes develop asynchronously. The estimated length-at-50% maturity (L EF50 ) was c. 181 cm (c. 4·8 years of age) for females. The proportion of reproductively active females in the spawning season with ovaries containing postovulatory follicles (0·27) indicated that they spawned every 3·7 days on average. The hydrated oocyte method estimated mean±S.D. batch fecundity (F B ) to be 4·4±2·02 million eggs; average relative fecundity was 53·6±13·9 oocytes g −1 M R ; and the average annual fecundity was 181·3±48·3million eggs. The parameters estimated in this study are key information for stock assessments of K. audax in the north-western and central Pacific and will contribute to the conservation, management and sustainable yield of this species.
Subjects
Billfish | Fecundity | Sex ratio | Sexual maturity | Size-at-50% maturity | Spawning season
Billfish; Fecundity; Sex ratio; Sexual maturity; Size-at-50% maturity; Spawning season
Other Subjects
anatomy and histology; animal; environmental protection; female; fertility; gonad; male; oocyte; ovary; Pacific Ocean; Perciformes; physiology; reproduction; season; sex ratio; sexual behavior; Animals; Conservation of Natural Resources; Female; Fertility; Gonads; Male; Oocytes; Ovary; Pacific Ocean; Perciformes; Reproduction; Seasons; Sex Ratio; Sexual Behavior, Animal
Publisher
WILEY
Type
journal article