Life-history traits of the spiny dogfish Squalus acanthias in the Adriatic Sea

Abstract

Pivotal life history traits concerning age structure and reproduction of the spiny dogfish (Squalus acanthias, Linnaeus 1758) were investigated in the Adriatic Sea from mid February 2012 to mid July 2013 and in 2016. The whole sample consisted of 176 females and 150 males, ranging between 217–1025 mm and 219–875 mm, respectively. The individual age, which was estimated using a cross-sectioning technique of the second dorsal-fin spine, ranged from 0 to 13+ years for females and from 0 to 9+ years for males. Based on the length-at-age estimates, the Gompertz growth parameters were L∞ = 1130 mm, k = 0.18 and L∞ = 920 mm, k = 0.24 for females and males, respectively. The size at sexual maturity (L50) was 659 mm for females and 575 mm for males, corresponding to 7.5 and 5.5 years of age (A50), respectively. Mean biennial fecundity was approximately 11 embryos/female and 12 ripe oocytes/female. Mature males occurred during much of the sampling period, while mature females with nearly full-term embryos were exclusively recorded in May 2013 and July 2016. Monitoring of catches conducted in a sample port of the north Adriatic (Chioggia) over the past 20 years has shown fluctuating trends in landings, with peaks during the summer reproductive season.

Growth and maturity of the lesser‐spotted dogfish Scyliorhinus canicula (Linnaeus, 1758) in the southern Portuguese continental coast

“…This was were reported in the North Atlantic Ocean (Ellis & Shackley, 1997;Henderson & Casey, 2001;Ivory et al, 2005). Differences in lifehistory traits across different latitudes are common in fish, particularly the increase in the size of a species towards higher latitudes, and has been reported in several elasmobranch species, such as the spiny dogfish Squalus acanthias and the angular angel shark Squatina guggenheim (Bargione et al, 2019;Colonello et al, 2007). Also, differences in lifehistory traits may reflect demographic differences among populations.…”

Consumer appreciation of a shark-free eco-label for small pelagics

“…Their sensitive biological characteristics limit the ability of these species to recover from heavy fishing pressure (Gallagher and Hammerschlag, 2011;Bargione et al, 2019). Spiny dogfish (Squalus acanthias) is one of the most valuable commercial sharks and is globally listed as vulnerable by the IUCN classification and as endangered in the Mediterranean Sea (Bargione et al, 2019). Common smooth-hound (Mustelus mustelus) is classified as vulnerable in the Mediterranean Sea (Farrell and Dulvy, 2016).…”

Estimating selectivity of experimental diamond (T0) and turned mesh (T90) codends in multi-species Mediterranean bottom trawl

“…The study was carried out in FAO Geographical Sub-Area 17 (North-western Adriatic Sea). This area, which is characterized by a wide and shallow continental shelf mainly consisting of sandy-muddy sediments, is intensively exploited by bottom trawlers (Colloca et al, 2017;Bargione et al, 2019). The trials were conducted 7-10 nm off the coast of Senigallia (central Italy; Fig.…”