Age, growth, reproduction and mortality of the striped seabream, Lithognathus mormyrus (Pisces, Sparidae), off the Canary Islands (Central-east Atlantic)

Abstract

Striped seabream, Lithognathus mormyrus L. (n=731) caught off the Canary Islands from January 1999 to June 2000 were studied. Fish ranged in size from 113 to 372 mm total length, weighing from 21.1 to 748.2 g total weight. Weight increased allometrically with size (b=2.9071). Fish age was 0–10‐years‐old. Growth was relatively slow (k=0.88 years−1), with females growing at a slightly faster rate than males. The species displayed protandric hermaphroditism. Male : female ratio was unbalanced in favour of males (1 : 0.85). Males predominated in smaller sizes, females in larger sizes, and intersexual individuals were in intermediate sizes. The reproductive season extended from June to December, with a peak in spawning activity in August–September. Males reached maturity at 207 mm (2 years) and females at 246 mm (3 years). The real value of instantaneous rate of natural mortality was between 0.30 and 0.45 years−1.

Age, growth, mortality, reproduction and feeding habits of the striped seabream, <i>Lithognathus mormyrus</i> (Pisces: Sparidae) in the coastal waters of the Thracian Sea, Greece

“…The differences are even more remarkable when one compares the results from the present study with those reported by Kraljevich et al (1995Kraljevich et al ( , 1996 for L. mormyrus from the northern Adriatic Sea and by Lorenzo et al (2002) from the centraleast Atlantic (Canary Islands). The population of L. mormyrus in the Thracian Sea reaches the same age as other populations of the Mediterranean Sea (Kraljevich et al, 1996) and of the central-east Atlantic (Lorenzo et al, 2002) but obtains a smaller size-atage. The asymptotic length (L∞) is found to be smaller than those estimated by Suau (1970), Kraljevich et al (1995Kraljevich et al ( -1996 and Lorenzo et al (2002).…”

“…The population of L. mormyrus in the Thracian Sea reaches the same age as other populations of the Mediterranean Sea (Kraljevich et al, 1996) and of the central-east Atlantic (Lorenzo et al, 2002) but obtains a smaller size-atage. The asymptotic length (L∞) is found to be smaller than those estimated by Suau (1970), Kraljevich et al (1995Kraljevich et al ( -1996 and Lorenzo et al (2002). The growth rate (k) of the species in the Thracian Sea is relatively slow, which is in agreement with the results of the other authors (Table 8).…”

“…The total mortality rate (Z = 0.79 year -1 ) of L. mormyrus caught with trammel nets gave a relatively high natural mortality rate (M = 0.61 years -1 ) compared with that of Kraljevich et al (1996) from the northern Adriatic Sea (M = 0.42) and Lorenzo et al (2002) from the central-east Atlantic (M between 0.3 and 0.45 years -1 ). The low fishing mortality rate (F = 0.18 years -1 ) suggests that the trammel net fishery may be sustainable.…”

“…These results agree with those of Kraljevic et al (1995Kraljevic et al ( , 1996 from the northern Adriatic Sea and Suau (1970) from the Castellón coast (eastern Spain) for fish ranging between 100 and 200 mm in TL. However, they contrast with those of Kraljevic et al (1995) in the middle Adriatic Sea (negative allometric growth), Suau (1970) for fish ranging between 210 and 290 mm TL (positive allometric growth), Lorenzo et al (2002) from the Canary Islands (negative allometric growth and difference between sexes) and Gonçalves et al (1997) from the southwest coast of Portugal (negative allometric growth). The length-weight relationship may be influenced by sex, maturity, geographical location and environmental condition (Balon, 1984;Bagenal and Tesch, 1978).…”

“…mormyrus is a protandric hermaphrodite fish (Bessau, 1990). Aspects of its reproduction, age and growth have been studied in the northern and middle Adriatic Sea (Kraljevic et al, 1995;Kraljevic et al, 1996), in eastern Spanish coastal waters (Suau, 1955(Suau, , 1970 and in the central-east Atlantic (Lorenzo et al, 2002;Pajuelo et al, 2002). Its diet has been investigated in eastern Spanish coastal waters (Suau, 1970), in the western Adriatic Sea (Froglia, 1977) and in the northwestern coastal waters of Sicily (Badalamenti et al, 1992).…”