Showing papers by "Branko Glamuzina published in 2006"

Length–weight relationships for selected fish species from three eastern Adriatic estuarine systems (Croatia)

Abstract: Summary Length–weight relationships are presented for fish species from three eastern Adriatic estuarine systems (Croatian waters). The values of the parameter b mostly remained within the expected range of 2.5–3.5. No information regarding the length–weight relationship previously existed for 11 of the species.

Maturation, reproduction and recruitment of the sand smelt, Atherina boyeri Risso, 1810 (Pisces:Atherinidae) in the estuary of Mala Neretva River (southeastern Adriatic, Croatia)

Abstract: Characteristics of maturation and recruitment of the sand smelt, Atherina boyeri, from the Mala Neretva River estuary in the southeastern Adriatic, Croatia in 2001/2, are presented. The average gonadosomatic index (GSI) during a 12-month period was 1.59% for females and 2.1% for males. The highest value was in April, 5.4% for females and 4.7% for males. The smallest mature female was 5.2 cm total length. Fifty percent of the females were mature at 7.75 cm total length. New juveniles began to recruit in June and July and later appeared in fewer numbers. In general, the GSI was lower than in other sand smelt populations. The reasons are difficult to determine but might be partly explained by the high and unpredictable temperature and salinity variations in the researched area that have led to previously described disturbances of the sand smelt life cycle, as in feeding and a high incidence of spinal deformities.

Age, growth, and mortality of the karamote shrimp, Melicertus kerathurus (Forskal, 1775), in the east Ionian Sea (western Greece).

Abstract: [Age, growth, and mortality of the karamote shrimp, Melicertus kerathurus (Forskal, 1775) [formerly: Penaeus k.], were determined for the native population in Amvrakikos Gulf (Ionian Sea; western Greece). Sampling was carried out on a monthly basis between June 1999 and May 2001. Carapace length ranged between 22 and 62 mm. Based on the carapace length frequency distribution, the Gulf population is composed mainly of individuals belonging to the first age class (0 and 1), and only a few from the other two expected age classes. Length frequency distributions and weight-at-age data were used to estimate the parameters of the Von Bertalanffy growth equations. For females, these were: CL∞ = 69.704 mm, TL∞ = 309.14 mm, W∞ = 123.01 g, K = 1.062 year−1, t0 = 0.238 years. For males: CL∞ = 62.658 mm, TL∞ = 274.18 mm, W∞ = 115.979 g, K = 1.253 year−;1, t0 = 0 years. Von Bertalanffy parameters for pooled data were: CL∞ = 59.695 mm, t0 = 0 and K = 1.047 year−1 and TL∞ = 246.79 mm, t0 = 0.410 and K = 0.629 year−1 and W∞ = 92.88 g based on TL. The overall length-weight relationship was: log W = −1.767 + 2.037 log TL (r2 = 0.842, N = 5505). Total mortality Z and natural mortality M rates for combined sexes were 2.26 year−1 and 1.15 year−1, respectively. The exploitation ratio E was estimated to be 49%. L'âge, la croissance et la mortalite de la crevette caramote Melicertus kerathurus (Forskal, 1775) [precedemment : Penaeus k.] ont ete determines pour la population autochtone du golfe d'Amvrakikos (mer Ionienne, ouest de la Grece). Des echantillons ont ete effectues mensuellement entre Juin 1999 et Mai 2001. La longueur de la carapace etait comprise entre 22 et 62 mm. La frequence de distribution de la longueur de la carapace montre que la population du golfe est surtout composee d'individus de la 1ere classe d'âge (0 et 1) et seulement de peu des deux autres classes attendues. La frequence de distribution de la longueur et les donnees poids versus âge ont ete estimees a partir des parametres de la courbe de croissance de Von Bertalanffy. Pour les femelles, ces parametres sont: CL∞ = 69,704 mm, TL∞ = 309,14 mm, W∞ = 123,01 g, K = 1,062 ans− 1, t0 = 0,238 ans. Pour les mâles: CL∞ = 62,658 mm, TL∞ = 274,18 mm, W∞ = 115,979 g, K = 1,253 ans−1, t0 = 0 ans. Les parametres de Von Bertalanffy pour les donnees conjointes sont: CL∞ = 59,695 mm, t0 = 0 et K = 1,047 ans−1 et TL∞ = 246,79 mm, t0 = 0,410 et K = 0,629 ans−1 et W∞ = 92,88 g sur la base de TL. La relation generale longueur-poids est: log W = −1,767 + 2,037 log TL (r2 = 0,842, N = 5505). Les taux de mortalite totale Z et de mortalite naturelle M, combines pour les deux sexes, sont 2,26 ans−1 et 1,15 ans−1, respectivement. Le ratio d'exploitation a ete estime a 49%., Age, growth, and mortality of the karamote shrimp, Melicertus kerathurus (Forskal, 1775) [formerly: Penaeus k.], were determined for the native population in Amvrakikos Gulf (Ionian Sea; western Greece). Sampling was carried out on a monthly basis between June 1999 and May 2001. Carapace length ranged between 22 and 62 mm. Based on the carapace length frequency distribution, the Gulf population is composed mainly of individuals belonging to the first age class (0 and 1), and only a few from the other two expected age classes. Length frequency distributions and weight-at-age data were used to estimate the parameters of the Von Bertalanffy growth equations. For females, these were: CL∞ = 69.704 mm, TL∞ = 309.14 mm, W∞ = 123.01 g, K = 1.062 year−1, t0 = 0.238 years. For males: CL∞ = 62.658 mm, TL∞ = 274.18 mm, W∞ = 115.979 g, K = 1.253 year−;1, t0 = 0 years. Von Bertalanffy parameters for pooled data were: CL∞ = 59.695 mm, t0 = 0 and K = 1.047 year−1 and TL∞ = 246.79 mm, t0 = 0.410 and K = 0.629 year−1 and W∞ = 92.88 g based on TL. The overall length-weight relationship was: log W = −1.767 + 2.037 log TL (r2 = 0.842, N = 5505). Total mortality Z and natural mortality M rates for combined sexes were 2.26 year−1 and 1.15 year−1, respectively. The exploitation ratio E was estimated to be 49%. L'âge, la croissance et la mortalite de la crevette caramote Melicertus kerathurus (Forskal, 1775) [precedemment : Penaeus k.] ont ete determines pour la population autochtone du golfe d'Amvrakikos (mer Ionienne, ouest de la Grece). Des echantillons ont ete effectues mensuellement entre Juin 1999 et Mai 2001. La longueur de la carapace etait comprise entre 22 et 62 mm. La frequence de distribution de la longueur de la carapace montre que la population du golfe est surtout composee d'individus de la 1ere classe d'âge (0 et 1) et seulement de peu des deux autres classes attendues. La frequence de distribution de la longueur et les donnees poids versus âge ont ete estimees a partir des parametres de la courbe de croissance de Von Bertalanffy. Pour les femelles, ces parametres sont: CL∞ = 69,704 mm, TL∞ = 309,14 mm, W∞ = 123,01 g, K = 1,062 ans− 1, t0 = 0,238 ans. Pour les mâles: CL∞ = 62,658 mm, TL∞ = 274,18 mm, W∞ = 115,979 g, K = 1,253 ans−1, t0 = 0 ans. Les parametres de Von Bertalanffy pour les donnees conjointes sont: CL∞ = 59,695 mm, t0 = 0 et K = 1,047 ans−1 et TL∞ = 246,79 mm, t0 = 0,410 et K = 0,629 ans−1 et W∞ = 92,88 g sur la base de TL. La relation generale longueur-poids est: log W = −1,767 + 2,037 log TL (r2 = 0,842, N = 5505). Les taux de mortalite totale Z et de mortalite naturelle M, combines pour les deux sexes, sont 2,26 ans−1 et 1,15 ans−1, respectivement. Le ratio d'exploitation a ete estime a 49%.]

Diet of Spondyliosoma cantharus and Diplodus puntazzo (Sparidae) in the Eastern Central Adriatic

Abstract: The stomach contents of Spondyliosoma cantharus and Diplodus puntazzo were analysed using three simple methods (numeric, gravimetric and frequency of occurrence) and a composite index (IRI-Index of relative importance). To compare the species, the Schoener index was used. The diet of S, cantharus consisted mainly of amphipods followed by polychaetes, ophiuroids and hydrozoans, while macrophyta, bivalves, spongids, polychaetes and ophiuroids dominated in the case of D. puntazzo. There were som size-related differences in S. cantharus and D.puntazzo feeding. Diet overlap was high and significant between species. Polychaetes were the dminantprey group in all seasons for S. cantharus, partiularly from spring to autumn. Significant differences among seasons were found for polychaetes, amphipods, ophiuroids and decapods. mean weight and mean nuber of prey significantly increased to spring-summer period. Macrophyta and bivalves were the dominant prey groups in all seasons for D. puntazzo, particularly from spring to summer. Significant differences among seasons were found for macrophyta, bivalves, ophiuroids and hydrozoans. Mean weight and mean number of prey significantly increased to spring-summer period.

SOME CHARACTERISTICS OF THE ENDEMIC DENTEX TROUT, Salmo dentex (Heckel, 1851) FROM THE NERETVA RIVER, BOSNIA-HERZEGOVINA

Abstract: Summary The paper confirms the presence of endemic dentex trout, Salmo dentex population in the Neretva River, Bosnia–Herzegovina. All catches were limited to main flow of the Neretva River close to town of ^apljina and colder areas of Hutovo Blato wetlands. All caught specimens of dentex trout fed on smaller fish. But, without preference to particular fish species.