Life‐history traits of the long‐nosed skate Dipturus oxyrinchus

This work investigates life‐history traits of the long‐nosed skate Dipturus oxyrinchus, which is a common by‐catch in Sardinian waters. The reproductive variables were analysed from 979 specimens sampled during scientific and commercial hauls. Females (10·4–117·5 cm total length, LT) attained larger...

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Bibliographic Details
Published in:Journal of fish biology 2017-03, Vol.90 (3), p.867-888
Main Authors: Bellodi, A., Porcu, C., Cannas, R., Cau, Al, Marongiu, M. F., Mulas, A., Vittori, S., Follesa, M. C.
Format: Article
Language:English
Subjects:
age
Age Determination by Skeleton
Animal Distribution
Animal Migration
Animals
Body Size
Female
Fertility
growth
Italy
Life History Traits
Male
maturity
Mediterranean Sea
Models, Biological
Reproduction
reproductive cycle
Sexual Maturation
skate
Skates (Fish) - growth & development
Spine - growth & development
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Summary:This work investigates life‐history traits of the long‐nosed skate Dipturus oxyrinchus, which is a common by‐catch in Sardinian waters. The reproductive variables were analysed from 979 specimens sampled during scientific and commercial hauls. Females (10·4–117·5 cm total length, LT) attained larger sizes than males (14·5–99·5 cm LT). To evaluate age and growth, a sub‐sample of 130 individuals (76 females and 54 males) were used. The age was estimated by annuli counts of sectioned vertebral centra. Four models were used for the length‐at‐age data: the von Bertalanffy, the exponential, the Gompertz and the logistic functions. According to the Akaike's information criterion, the Gompertz model seemed to provide the best fitting curve (L∞ mean ± s.e.: 127·55 ± 4·90 cm, k: 0·14 ± 0·09, IP: 3·97 ± 0·90 years). The oldest female and male were aged 17 (115·5 cm LT) and 15 years (96·0 cm LT), respectively. Lengths at maturity were 103·5 cm for females and 91·0 cm for males, corresponding to 90% of the maximum observed length in both sexes. The monthly distribution of maturity stages highlighted an extended reproductive cycle, with spawning females and active males being present almost throughout the year, as confirmed by the gonado‐somatic index. Ovarian fecundity reached a maximum of 26 yolked follicles with a mean ± s.e. size of 19·7 ± 6·5 mm.
ISSN:0022-1112
1095-8649
DOI:10.1111/jfb.13205