Age-based demographic and reproductive assessment of orangespine Naso lituratus and bluespine Naso unicornis unicornfishes

Taylor, B.M., Rhodes, K.L., Marshell, A., and McIlwain, J.L. (2014) Age-based demographic and reproductive assessment of orangespine Naso lituratus and bluespine Naso unicornis unicornfishes. Journal of Fish Biology, 85 (3). pp. 901-916.

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Bluespine unicornfish Naso unicornis and orangespine unicornfish Naso lituratus were sampled in Pohnpei and Guam, Micronesia, over 13 months to identify reproductive and age-based demographic features necessary for informed management. Age and reproductive information were derived from analysis of sagittal otoliths and gonads. Both species had moderate life spans [maximum ages of 23 (N. unicornis) and 14 years (N. lituratus)] compared with published estimates of conspecifics from other locations (>30 years) and of other Naso species. Length at maturation for N. unicornis was similar between Pohnpei and Guam while females consistently matured at a larger size [c. 30 cm fork length (LF)] than males (c. 27 cm LF). This sex-specific pattern was reversed in N. lituratus for which estimates of maturation length (females: 15 cm LF; males: 18 cm LF) were only obtained from Guam. Developmental patterns in female gonads of both species suggested that initiation of maturation occurs very early. Growth patterns of N. lituratus displayed rapid asymptotic growth compared with N. unicornis and other congeners as well as slight sex-specific patterns of length-at-age. Results highlight the considerable spatial variation that may occur in the population biology of these species across various scales. Additionally, proper management remains complicated without improved knowledge of fishery trends and reproductive behaviour in unicornfishes, species that are prime fishery targets in Micronesia and elsewhere.

Item ID: 35460
Item Type: Article (Research - C1)
ISSN: 1095-8649
Keywords: Acanthuridae, coral-reef fisheries, life history, Micronesia
Funders: U.S. Fish and Wildlife Service Sport Fish Restoration Programme (USFWS-WSFR), NOAA Coral Reef Conservation Program
Projects and Grants: USFWS-WSFR grant number F14-R1, NOAA NA09NMF4630108
Date Deposited: 29 Sep 2014 03:25
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050209 Natural Resource Management @ 30%
06 BIOLOGICAL SCIENCES > 0608 Zoology > 060809 Vertebrate Biology @ 70%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830299 Fisheries- Wild Caught not elsewhere classified @ 100%
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