Maturity ogives for South Pacific albacore tuna (Thunnus alalunga) that account for spatial and seasonal variation in the distributions of mature and immature fish

Farley, Jessica H., Hoyle, Simon D., Eveson, J. Paige, Williams, Ashley J., Davies, Campbell R., and Nicol, Simon J. (2014) Maturity ogives for South Pacific albacore tuna (Thunnus alalunga) that account for spatial and seasonal variation in the distributions of mature and immature fish. PLoS ONE, 9 (1). e83017. pp. 1-14.

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Abstract

Length and age at maturity are important life history parameters for estimating spawning stock biomass and reproductive potential of fish stocks. Bias in estimates of size and age at maturity can arise when disparate distributions of mature and immature fish within a population are not accounted for in the analysis. Here we investigate the spatial and temporal variability in observed size and age at maturity of female albacore tuna, Thunnus alalunga, using samples collected across the South Pacific. Maturity status was identified using consistent histological criteria that were precise enough to allow for mature but regenerating females to be distinguished from immature females during the non-spawning season, permitting year-round sampling for maturity estimation in albacore. Using generalised linear mixed models, we found that the proportion of mature females at length varied significantly with latitude and time of year. Specifically, females at northern latitudes (~10–20°S, where spawning occurs) were mature at significantly smaller lengths and ages than females at southern latitudes (~20–40°S), particularly during the spawning season (October–March). This variation was due to different geographic distributions of mature and immature fish during the year. We present a method for estimating an unbiased maturity ogive that takes into account the latitudinal variation in proportion mature at length during a given season (spawning or non-spawning). Applying this method to albacore samples from the western region of the South Pacific gave a predicted length at 50% mature of ~87 cm fork length (4.5 years).

Item ID: 31948
Item Type: Article (Research - C1)
ISSN: 1932-6203
Additional Information:

© 2014 Farley et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funders: CSIRO Wealth from Oceans Flagship, Australian Fisheries Research and Development Corporation (FRDC), 9th European Union Development Fund, Western and Central Pacific Fisheries Commission
Projects and Grants: FRDC Project #2009/012, 9th European Union Development Fund SCIFISH project
Date Deposited: 04 Jul 2014 04:59
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 100%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830207 Wild Caught Tuna @ 100%
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