Reproductive biology and spatiotemporal patterns of spawning in striped marlin Kajikia audax |
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| Authors: | R K Kopf P S Davie D B Bromhead J W Young |
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| Institution: | 1. Institute for Land, Water and Society, Charles Sturt University, P. O. Box 789, Albury, NSW 2640, Australia;2. Institute of Veterinary Animal and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand;3. Oceanic Fisheries Program, Secretariat of the Pacific Community, B. P. D5, 98848 Noumea Cedex, New Caledonia;4. Wealth from Oceans Flagship, CSIRO Marine and Atmospheric Research, G. P. O. Box 1538, Hobart, Tas 7001, Australia |
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| Abstract: | This study presents the first histology‐based assessment of the reproductive dynamics of south‐west Pacific striped marlin Kajikia audax. Maturity and reproductive status were assessed from histological sections of ovaries (n = 234) and testes (n = 243) of fish caught in commercial longline and recreational fisheries between 2006 and 2009. Spawning peaked in the Coral Sea during November and December at sea surface temperatures between 24·8 and 28·3° C. Lower jaw fork length (LLJF) at 50% maturity (LLJF50), a key variable for stock assessment, was estimated to be 2100 ± 102 mm (mean + s.e .) for females and 1668 ± 18 mm for males. Unlike large pelagic tunas Thunnus spp., the proportion of females increased with length and spawning fish formed multiple large‐scale aggregations within a broad latitudinal band. This study provides a starting point for biological parameters needed for stock assessment and conservation of K. audax and introduces the multiple aggregation spawning concept as a reproductive mechanism to explain genetic heterogeneity observed in some highly migratory species. |
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| Keywords: | batch spawning billfish Coral Sea Marine Reserve fecundity histology reproductive strategy |
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