Life-history traits of the long-nosed skate Dipturus oxyrinchus, from the central western Mediterranean Sea

Abstract

Event Abstract Back to Event Life-history traits of the long-nosed skate Dipturus oxyrinchus, from the central western Mediterranean Sea Andrea Bellodi1, Cristina Porcu1*, Martina F. Marongiu1, Antonello Mulas1, Stefania Vittori1 and Maria C. Follesa1 1 Università degli Studi di Cagliari, Life and Environmental Sciences, Italy Skates are often considered vulnerable to overfishing because of their peculiar life cycle characteristics rendering them susceptible to overexploitation. In this regard, life-history traits of a by-catch species, the long-nosed skate Dipturus oxyrinchus (Linnaeus, 1758) from Sardinian waters, were investigated. The age, growth and reproduction were studied using 706 specimens sampled during experimental and commercial hauls (depths 76-671 metres). Females (10.4-117.5 cm in total length, TL) attained larger sizes than males (14.5-99.5 cm TL). To evaluate the growth, a subsample of 130 individuals (76 females and 54 males) was employed. The age was estimated through the annuli counts on sectioned vertebral centra. A high ageing reproducibility and precision was obtained (Index of Average Percent Error=6.56; %CV=8.9). Four models were applied on length at age data: the von Bertalanffy (VBGF), the Exponential, the Gompertz and the Logistic functions. According to the Akaike’s Information Criterion, the Gompertz model (L∞=127.5±4.9 cm; k=0.14±0.009; inflection point=3.97 y-1±0.9) provided the best fitting curve, showing a higher growth rate and a lower L∞ than what obtained with the VBGF (L∞=144.4±11.5 cm; k=0.08±0.001; t0=-1.09±0.23). The oldest female and male were 17 (115.5 cm TL) and 15 years (96 cm TL), respectively. Lengths at maturity were 103.5 cm (14 years) for females and 91 cm (12.1 years) for males corresponding to 88 and 91.5% of the maximum observed length, respectively. The monthly evolution of maturity stages highlighted an extended reproductive cycle with spawning females and active males almost over the year, as confirmed by the Gonado-somatic Index. Ovarian fecundity reached a maximum of 26 yolked follicles. Given the relative abundance in Sardinian seas, we hope that these results will prove useful for the implementation of basic management measures in order to ensure the sustainability of catches of this species, particularly sensitive to fishing pressure, in the Mediterranean Sea. Keywords: Dipturus oxyrinchus, age, Growth, Reproduction, Mediterranean Sea Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Life Cycles, Migration and Connectivity Citation: Bellodi A, Porcu C, Marongiu MF, Mulas A, Vittori S and Follesa MC (2015). Life-history traits of the long-nosed skate Dipturus oxyrinchus, from the central western Mediterranean Sea. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.FMARS.2015.03.00193 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Nov 2015; Published Online: 02 Dec 2015. * Correspondence: Dr. Cristina Porcu, Università degli Studi di Cagliari, Life and Environmental Sciences, Cagliari, 09126, Italy, cporcu@unica.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Andrea Bellodi Cristina Porcu Martina F Marongiu Antonello Mulas Stefania Vittori Maria C Follesa Google Andrea Bellodi Cristina Porcu Martina F Marongiu Antonello Mulas Stefania Vittori Maria C Follesa Google Scholar Andrea Bellodi Cristina Porcu Martina F Marongiu Antonello Mulas Stefania Vittori Maria C Follesa PubMed Andrea Bellodi Cristina Porcu Martina F Marongiu Antonello Mulas Stefania Vittori Maria C Follesa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.