Research of biological and ecological characteristics of invasive species Magallana gigas in Adriatic sea

Pacifička kamenica Magallana gigas (Thunberg, 1793) unesena je 1960-ih godina u Europu za potrebe akvakulture. U Jadranu je prvi put opisana 1970-ih godina u Limskom zaljevu, ali nije nikad uzgajana u Hrvatskoj. Do danas je zabilježeno jako malo dostupnih podataka o ovoj invazivnoj vrsti u Jadranu. Cilj ovog diplomskog rada bio je opisati reproduktivni ciklus te brojnost i strukturu populacije pacifičke kamenice u Limskom zaljevu. Istraživanje je provedeno u periodu od veljače 2017. do listopada 2018. godine tijekom kojeg se pratio reproduktivni ciklus pacifičke kamenice putem histološke analize gonadnog tkiva. Nadalje, na četiri lokacije unutar Limskog zaljeva provela se analiza brojnosti te duţinske strukture ove vrste. Rezultati su pokazali da su uvjeti u Limskom zaljevu pogodni za razmnoţavanje vrste M. gigas te se ona mrijesti uglavnom u ljetnom periodu. Muţjaci i ţenke imali su sinkroni reproduktivni ciklus s malim razlikama u procesu gametogeneze. Brojnost ove vrste u Limskom zaljevu bila je jako visoka te se kretala od 33 do 248 jedinki/m2. Raspon veličina kretao se od 21 do 89 mm. Navedeni podatci predstavljaju prve kvantitativne podatke za ovu vrstu u Jadranu te zajedno s rezultatima reproduktivnog ciklusa potvrĎuju da je pacifička kamenica u Limskom zaljevu uspostavila samoodrţive divlje populacije.Pacific cupped oyster Magallana gigas (Thunberg, 1793) was introduced to Europe in the 1960s for aquaculture purposes. It was first described in the Adriatic Sea in the 1970s, in the Lim Bay, though this species has never been cultivated in Croatia. There are still very limited available information about this invasive species in the Adriatic. The aim of this thesis was to describe the reproductive cycle, size and structure of population of the Pacific cupped oyster in the Lim Bay. The research was carried out in the period from February 2017 to October 2018 during which the reproductive cycle of the Pacific cupped oyster was followed through the histological analysis of the gonadal tissue. Furthermore, on four locations along the Lim Bay analysis of the size of the length structure of this species was conducted. The results showed that the conditions in the Lim Bay are suitable for reproduction of this type of M. gigas and that it spawns mainly in the summer period. Male and female oysters had a synchronous reproductive cycle with minor differences in the process of gametogenesis. Population of this oyster species in the Lim Channel was very high and ranged from 33 to 248 individuals/m2. The range in size varied from 21 to 89 mm. The given data represents the first quantiative figures for this species in the Adriatic Sea and prove, together with the reproductive cycle results, that the Pacific cupped oyster in the Lim Bay has developed self-sustaining wild populations