External morphometrics were quantified and compared with body size for adults of an Oahu (Hawaii) population of the Bluespine Unicornfish (Naso unicornis). Specimens were obtained by monthly fishery-dependent collections during the period from April 2011 to July 2012. Three apparently size-related, sexually dimorphic traits were measured (cephalic horn length, to the nearest mm; several measures of peduncular keel/spine development, 0.1 mm; caudal fin filament length, mm) using dial calipers and related to fork length (FL, mm) for individuals of each sex. Histological slides of sub-adult and adult gonads were examined microscopically, and sexual identity and gonadal development and maturation were scored using standard criteria. Each of the metrics examined was sexually dimorphic and positively related to FL using simple linear regression. Logistic regression was used to evaluate the relative ability of each metric, or some combination thereof, to predict the sex of an individual fish. Although combinations of two or all three metrics accurately predicted sex, a single metric (peduncle width across the posterior keel) provided the most efficient and accurate (80% [75–84%, 95% CI] successful) predictor of an individual's sexual identity. Thus a single measure can be used to sex fish in the field. The implications of this finding relative to studies of the movement ecology and life history of this ecologically and economically important species are discussed.
Skip Nav Destination
Article navigation
Articles|
June 14 2016
Sexual Dimorphisms in the Bluespine Unicornfish, Naso unicornis (Acanthuridae): External Metrics for Movement Ecology and Life History
Edward E. DeMartini
Edward E. DeMartini
1NOAA Fisheries, Inouye Regional Center, Fisheries Research and Monitoring Division, 1845 Wasp Boulevard, Building 176, Honolulu, Hawaii 96818; and Hawaii Institute of Marine Biology, University of Hawaii, School of Earth Science and Technology, Kaneohe, Hawaii 96744; Email: edward.demartini@noaa.gov.
Search for other works by this author on:
Copeia (2016) 104 (2): 498–505.
Citation
Edward E. DeMartini; Sexual Dimorphisms in the Bluespine Unicornfish, Naso unicornis (Acanthuridae): External Metrics for Movement Ecology and Life History. Copeia 1 July 2016; 104 (2): 498–505. doi: https://doi.org/10.1643/CE-15-270
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionCiting articles via
Temperature and Development Drive Variation in Oral Morphology among Tailed Frog (Ascaphus spp.) Populations
A. S. Cicchino, C. M. Martinez, W. C. Funk, B. R. Forester
A New Genus and Two New Species of Tetras (Characiformes: Characidae), with a Redescription and Generic Reassignment of Axelrodia lindeae Géry
André L. H. Esguícero, Marina B. Mendonça
Demographics, Reproductive Characteristics, and Genetic Connectivity of Blue Suckers (Cycleptus elongatus) in a Large Tributary
Dakota S. Radford, Anthony P. Porreca, Cassi J. Moody-Carpenter, Kathryn A. Muller, Devon B. Keeney, Robert E. Colombo
Genomic Data Do Not Support the Species Status of the San Luis Valley Short-Horned Lizard (Phrynosoma diminutum)
Julianna Hoza, Hayden R. Davis, Adam D. Leaché