51 research outputs found

    Biometrijske osobine šnjura pučinara, Trachurus mediterraneus, (Osteichthyes: Carangidae) u srednjem Jadranu

    Get PDF
    The relationship between morphometric measurements (15) and meristic characters (8) were examined in 237 specimens of Mediterranean horse mackerel (105 females, 101 males and 31 immature specimens) caught in the central Adriatic Sea. The goal of this paper was to investigate: whether there are morphological differences between males and females; the existence of homogenous or heterogeneous morphology stock; changes in morphometric characters with an increase in body length. Morphological differences between males and females were not marked. Modal values specific for Trachurus species morphologic characters, such as number of lateral line scales, maximum height of scales in anterior and posterior part of lateral line, point at which dorsal accessory lateral line is terminated and values of other biometric properties indicated a possible homogeneous morphology stock of T. mediterraneus in the central Adriatic Sea. Changes in some morphometric characters obtained in conjunction with an increase in body length showed that smaller specimens have longer head, anal and ventral fin than adult specimens. On the other hand, with an increase in total length, the fish have larger preorbital and postorbital distance, smaller eye and maximum height of scales in the lateral line than smaller fishes. The negative correlation recorded for the maximum and minimum body depth indicates that the body becomes progressively elongated. The meristic characters of Mediterranean horse mackerel from different Mediterranean and NE Atlantic areas are mostly in agreement with the data in our study.Na 237 primjeraka šnjura pučinara (105 ženki, 101 mužjak i 31 spolno nezrelih jedinki) ulovljenih u srednjem Jadranu analizirana su morfometrijska (15) i meristička obilježja (8). Cilj ove studije bio je istražiti morfološke razlike između mužjaka i ženki, postojanje morfološki homogenog ili heterogenog stoka i promjene morfometrijskih osobina tijekom rasta ribe. Morfološke razlike između mužjaka i ženki nisu izražene. Modalne vrijednosti specifičnih morfoloških obilježja, kao što su broj ljusaka u bočnoj pruzi, najveća visina ljusaka u prednjem i stražnjem dijelu bočne pruge i točka gdje završava dodatna leđna bočna pruga te vrijednosti ostalih biometrijskih osobina ukazuju da u Jadranu vjerojatno obitava morfološki homogena populacija ove vrste. Uočene su promjene morfometrijskih odnosa u vezi s porastom tjelesne dužine. Manji primjerci imaju veću dužinu glave, podrepnu i trbušne peraje nego veći primjerci. S druge strane veće ribe imaju veću predočnu i zaočnu udaljenost, manju veličinu oka i manju visinu ljusaka u bočnoj pruzi u odnosu na manje ribe. Negativna korelacija zabilježena kod najmanje i najveće visine tijela pokazuje da se tijelo ribe progresivno izdužuje. Merističke osobine šnjura pučinara s različitih područja Mediterana i sjeveroistočnog Atlantika uglavnom se podudaraju s podacima dobivenim u ovom radu

    Algunos parámetros biológicos de la señorita, Symphodus (Crenilabrus) tinca (L.1758) (Pisces: Labridae) del Adriático central oriental (costa croata)

    Get PDF
    Data on sex ratio, length-weight relationship, age, growth and survival rate were analysed for peacock wrasse, Symphodus (Crenilabrus) tinca L., (total = 1443; males = 848, females = 595) collected in the eastern middle Adriatic island area during the reproductive period (April and May) from 1995 to 1999. The total length of sampled specimens ranged from 8.9 to 42.5 cm and the weight from 7.9 to 764.2 g. The overall sex ratio was 1.43:1 in favour of males. All individuals larger than 28.9 cm were males as an effect of faster growth. The oldest females were 12 and the oldest males 13 years old. The von Bertalanffy growth formula was estimated for females (L∞ = 28.14; k = 0.294; t0 = - 0.775) and males (L∞ = 42.24; k = 0.214; t0 = - 0.628). The slopes (b values) of total length - weight regressions indicated allometric growth for males (b = 2.7205) and both sexes (b = 2.8147) and isometric growth for females (b = 2.9901). Survival rate of males (S = 0.80) was slightly greater than that for females (0.756).Datos sobre la proporción de sexos, relación talla-peso, edad, crecimiento y tasa de supervivencia se han analizado para la señorita, Symphodus (Crenilabrus) tinca L., (total = 1443; machos = 848, hembras = 595) capturados en la zona de islas del Adriático central oriental durante el periodo de reproducción (Abril y Mayo) entre 1995 y 1999. La talla total de los individuos muestreados osciló entre 8.9 y 42.5 cm y el peso entre 7.9 y 764.2 g. La proporción de sexos total fue 1.43:1 a favor de los machos. Todos los individuos mayores de 28.9 cm fueron machos, como efecto de un mayor crecimiento. Las hembras de más edad fueron de 12 años, y los machos de 13. La ecuación de crecimiento de von Bertalanffy fue estimada para hembras (L? = 28.14; k = 0.294; t0 = -0.775) y machos (L? = 42.24; k = 0.214; t0 = -0.628). Las pendientes (valores de b) de las regresiones longitud total - peso indicaron crecimiento alométrico para los machos (b = 2.7205) y para el conjunto de ambos sexos (b = 2.8147) y crecimiento isométrico para hembras (b = 2.9901). La tasa de supervivencia de los machos (S = 0.80) fue ligeramente mayor que la de las hembras (0.756)

    The roughtail stingray Dasyatis centroura

    No full text
    corecore