Abstract
Age and growth of the black scorpionfish, Scorpaena porcus , were estimated for different populations inhabiting natural reefs and artificial structures (artificial reefs and offshore gas platforms) in the northwestern Adriatic Sea. Annual growth increment counts were carried out on sagittal otoliths of 415 specimens ranging from 80 to 280 mm TL. The accuracy of age estimates was assessed by testing the annual deposition of annuli and the location of the first annulus by marginal increment analysis and daily growth increment counts, respectively. As commonly observed in other scorpaenids, annuli consisted of an alternating pattern of opaque and translucent zones. Marginal increment analysis confirmed that annuli are formed once a year, with opaque zones laid down in spring-summer and translucent zones laid down in autumn-winter. The precision of age estimates was tested by applying both the average percent error (APE) and the mean coefficient of variation (CV). The maximum age estimated for the whole sampled populations was 8 years. The von Bertalanffy growth curves were separately fitted for natural and artificial reef populations of S. porcus . The likelihood ratio test indicated that the overall von Bertalanffy growth curves differed significantly between the two populations. The instantaneous growth rate ( k , year -1 ) and asymptotic length (L ∞ , cm) were 0.23 and 22.30 and 0.53 and 20.13 for natural and artificial reef populations, respectively. Compared with natural reef population, populations of S. porcus inhabiting artificial reefs and, particularly, offshore platforms, were characterized by larger and older fish. However, young-of-the-year were completely absent from the platform habitats. The effects of artificial structures on S. porcus populations in the study area are discussed in the light of previous results on scorpionfish living in other areas.
Highlights
In the Mediterranean Sea, the genus Scorpaena is the most speciose group of scorpionfish, including six species, such as Scorpaena elongata Cadenat, 1943, Scorpaena loppei Cadenat, 1943, Scorpaena maderensis Valenciennes, 1833, Scorpaena notata Rafinesque, 1810, Scorpaena porcus Linnaeus, 1758, and Scorpaena scrofa Linnaeus, 1758 (Hureau and Litvinenko, 1986; Quignard and Tomasini, 2000)
In this study we report the age composition and growth rate of S. porcus estimated by otolith reading, applying indirect methods to evaluate the reliability and reproducibility of age estimates
134 specimens of 110-221 mm total length (TL) were caught at the natural reefs (NR), 210 specimens of 80-270 mm TL were caught at the artificial reefs (AR) and 71 specimens of 135-280 mm TL were caught at the PL
Summary
In the Mediterranean Sea, the genus Scorpaena is the most speciose group of scorpionfish, including six species, such as Scorpaena elongata Cadenat, 1943, Scorpaena loppei Cadenat, 1943, Scorpaena maderensis Valenciennes, 1833, Scorpaena notata Rafinesque, 1810, Scorpaena porcus Linnaeus, 1758, and Scorpaena scrofa Linnaeus, 1758 (Hureau and Litvinenko, 1986; Quignard and Tomasini, 2000). Sedentary littoral species of medium size (up to 25 cm), commonly found in inshore waters among rocks and seagrass beds (Hureau and Litvinenko, 1986) It is more active and spatially dispersed in search of food by night (Pashkov et al, 1999), feeding mainly on benthic preys such as small fishes (gobies and blennies), crustaceans and other invertebrates (Bradai and Bouain, 1990; Pallaoro and Jardas, 1991; Carpentieri et al, 2001; Morte et al, 2001; Relini et al, 2002; Silvestri et al, 2002; Follesa et al, 2004). S. porcus is typically a sit-and-wait ambusher, feeding almost exclusively on motile prey (Harmelin-Vivien et al, 1989)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
