| Abstract | Tijekom ovog istraživanja u istočnom je Jadranu ulovljeno 1375 jedinki škrpuna, Scorpaena
porcus (Linnaeus, 1758), raspona ukupne dužine tijela od 2,0 do 28,1 cm (15,30 ± 3,47 cm) i
mase od 0,20 do 493,30 g (81,98 ± 55,75 g). Omjer ženki i mužjaka je iznosio 1:0,65, a pri
ukupnim su dužinama tijela većim od 24,0 cm u potpunosti dominirale ženke. Dužinsko –
maseni rast škrpuna je negativno alometrijski (b = 2,984), a vrijednost indeksa kondicije je
relativno visoka (IK = 2,062). Zabilježene su statistički značajne razlike u srednjim
vrijednostima sedam morfometrijskih odnosa između ženki i mužjaka. Intenzitet hranjenja
škrpuna je bio najveći tijekom ljeta, a neophodni plijen su deseteronožni rakovi i ribe. Starost
škrpuna je određena očitavanjem otolita na kojima su se opaki prstenovi stvarali ljeti. Rast
škrpuna je opisan von Bertalanffyevim modelom rasta (L∞ = 30,45 cm; K = 0,12; t0 = -2,60; R2
= 0,790), a u populaciji su najbrojnije bile jedinke starosti 4 i 5 godina. Najstarija je ženka škrpuna
imala 12 godina, a najstariji mužjak 10, pa je rast između spolova i statistički značajan. Starost
škrpuna se može najbolje procijeniti iz dužine otolita. Fekunditet ženki je relativno nizak, a ova
se vrsta u Jadranu mrijesti od svibnja do rujna, dok su najveće srednje vrijednosti
gonadosomatskog indeksa zabilježene u srpnju. Kod mužjaka je zabilježeno veće prisustvo
vakuola u hepatocitima, a koncentracije većine biokemijskih parametara u krvi škrpuna su
porasle tijekom toplijih mjeseci. Vrijednosti ribolovne smrtnosti škrpuna (0,553) su dosta veće
od vrijednosti prirodne smrtnosti (0,128). Škrpun je novi domaćin za 4 vrste vanjskih nametnika
u istočnom Jadranu. U razdoblju od 1993. do 2009. godine, uočen je pozitivan trend u brojčanom
i masenom ulovu škrpuna po mreži poponici, ali i smanjenje ukupne dužine i mase tijela ove
vrste u istočnom Jadranu. |
| Abstract (english) | In the present study, a total of 1375 specimens of the black scorpionfish, Scorpaena porcus (Linnaeus, 1758), ranging from 2.0 to 28.1 cm (15.30 ± 3.47 cm) in total length and from 0.20 to 493.30 g (81.98 ± 55.75 g) in weight were collected in the eastern Adriatic. Female-to-male ratio was 1:0.65 and for lengths of over 24.0 cm, only females were caught. The length-weight relationship showed a negative allometric growth (b = 2.984) and estimated condition factor was relatively high (CF = 2.062). The differences between the seven mean values of the measured morphometric characteristics in females and males were statistically significant. The highest feeding intensity of the black scorpionfish was recorded during summer and the dominant food component were decapods and fish. Age of the fish was determined by otolith reading and the opaque zones were formed in summer. The growth of the black scorpionfish was described using the von Bertalanffy growth model (L∞ = 30.45 cm; K = 0.12; t0 = -2.60; R2 = 0.790) and the samples were dominated by 4 and 5 year old specimens. Maximum ages for females and males were 12 and 10 years, respectively, so growth of females and males was significantly different. The most precise age estimations were obtained from the otolith length. The fecundity of females was relatively low, while spawning takes place between May and September, with a peak in July. Hepatocyte vacuoles were more numerous in males, while concentrations of the most measured biochemistry parameters in blood were higher during warmer months of the year. Fishing mortality (0.553) was much higher than observed natural mortality (0.128). The black
scorpionfish is a new host record of four ectoparasite species. Between 1993 and 2009, positive trends for abundance and biomass catch per trammel net and a decline in total length and mass of the black scorpionfish were observed in the eastern Adriatic. |
