Age, growth, reproduction and feeding of the spurdog (Squalus acanthias Linnaeus, 1758) in the South-Eastern Black Sea


Avsar D.

ESTUARINE COASTAL AND SHELF SCIENCE, cilt.52, ss.269-278, 2001 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 52 Konu: 2
  • Basım Tarihi: 2001
  • Doi Numarası: 10.1006/ecss.2000.0749
  • Dergi Adı: ESTUARINE COASTAL AND SHELF SCIENCE
  • Sayfa Sayısı: ss.269-278

Özet

Life-history parameters and diet of spurdog (Squalus acanthias) sampled from the SE Black Sea were studied. Spurdog from age classes I to XIV were identified, with a dominance of age class VIII for both sexes. The length-weight relationship was W=0.0040*L-2.95 and the mean annual growth rates in length and weight were 7.2 cm and 540.1 g, respectively. The estimated von Bertalanffy growth parameters were: W-infinity = 12021 (g), L-infinity = 157 (cm), K = 0.12 (year(-1)) and t(0) = -1.30 (year). The size at first maturity was 82 cm for males and 88 cm for females. Mean biennial fecundity was also found to be 8 pups/female. The relationships between fecundity-length, fecundity-weight and fecundity-age were found to be: F = -17.0842 + 0.2369*L (R = 0.93), F = 0.3780 + 0.0018*W (R = 0.89) and F = - 0.7859 + 1.1609*A (R = 0.94) respectively. The spurdog can be considered an opportunistic feeder. Their natural diet was composed mainly of teleost fishes, followed by Crustaceans, Nematodes and Actinarians (= sea anemones). Whiting (Merlangius merlangus euxinus) was the predominant prey item among their fish prey. Demersal teleosts formed the majority of the diet, and there was no difference (P > 0.05) among the food items of immature, maturing and mature individuals of both sexes. (C) 2001 Academic Press.