University of Zagreb. Faculty of Science. Department of Biology.
Abstract
Oštrulja (Aulopyge huegelii, Heckel, 1843) pripada porodici Cyprinidae (šaranke) te je jedini predstavnik roda Aulopyge. Oštrulja je endem jadranskog slijeva, a u Hrvatskoj se može pronaći u rijekama Cetini, Krki i Čikoli. Cilj ovog rada je kombinacijom morfometrijskih i histomorfometrijskih mjerenja te gonadosomatskog indeksa, dobiti dosad nepoznate informacije o osnovnim reproduktivnim karakteristikama ove ugrožene vrste. Jedinke su prikupljene u rijekama Krki i Čikoli, a ukupno je analizirano 29 jedinki muškog i 57 jedinki ženskog spola. Ženke dosežu veće duljine tijela od mužjaka (prosječna standardna duljina tijela mužjaka bila je 103,93 mm, a ženki 112,71 mm). Najveća izmjerena masa tijela za mužjaka je 47,60 g, a za ženku 53,74 g. Izračunat je gonadosomatski indeks (GSI), čije vrijednosti dosežu vrhunac u travnju te postupno opadaju do srpnja. Histomorfometrijska mjerenja trajnih preparata testisa pokazuju da su svi analizirani mužjaci spolno zreli. Izmjerena je veličina jaja u jajnicima i određen broj zrelih jaja, odnosno izračunat je fekunditet jednog mrijesta (BF), koji je iznosio od 68 do 1154 zrelih jaja. Zrela jaja pronađena su samo kod ženki ulovljenih od travnja do srpnja. Rezultati pokazuju da reproduktivni ciklus oštrulje počinje u travnju (pri temperaturama od oko 12 °C) i traje do kraja srpnja. Rezultati ovog rada mogu biti primjenjivi u planiranju znanstveno utemeljene zaštite za ovu vrstu u regionalnim krškim rijekama i jezerima.The Dalmatian barbelgudgeon (Aulopyge huegelii, Heckel, 1843) belongs to the family Cyprinidae and is the only member of the genus Aulopyge. This species is endemic to the Adriatic Basin, and can be found in the Croatian rivers Cetina, Krka and Čikola. The aim of this study was to obtain previously unknown information on reproduction of this endangered species, using a combination of morphometric and histomorphometric measurements and gonadosomatic index. The specimens were collected in the rivers Krka and Čikola, a total of 29 male and 57 female individuals. Females reach greater body length than males (average standard body lenght for males was 103,93 mm, and 112,71 mm for females). The highest measured body weight for males was 47,60 g and 53,74 g for females. Gonadosomatic index was calculated and its values reach maximum in April, then gradually decline to July. Histomorphometric analysis of testes showed that all analysed males were sexually mature. Size of the eggs in the ovaries was measured and the number of mature eggs was determined. Fecundity of one spawning ("batch fecundity") was calculated and it was in range from 68 to 1154 mature eggs. Mature eggs were only found in females captured from April to July. The results show that the reproductive cycle of this species begins in April (at temperatures of about 12 ° C) and lasts until the end of July. The results of this study can be used in the planning of science-based protection of this species in regional karst rivers and lakes
