Naslov
Oyster beds in the Northern Adriatic - current state and restoration potential

Autori
Ezgeta-Balić, Daria ; Oraić, Dražen ; Pavlinec, Željko ; Vujević, Ante ; Vrgoč, Nedo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
NORA 4 - Reconnecting across Europe / - , 2021, 59-59

Skup
Native Oyster Restoration Alliance Reconnecting across Europe (NORA 4 2021)

Mjesto i datum
Online, 23.11.2021. - 26.11.2021

Vrsta sudjelovanja
Poster

Vrsta recenzije
Recenziran

Ključne riječi
Adriatic Sea, oyster reproduction, parasites, beam trawl

Sažetak
European flat oyster Ostrea edulis is one of the most commercially important species harvested in the Croatian part of the Adriatic Sea. Although it is present all along the eastern Adriatic coast, the main fishing ground for this species is the Northern Adriatic Sea. In that area, oysters are harvested by beam trawlers. The part of the Northern Adriatic where oyster beds are present is a relatively shallow offshore area with a depth up to around 35 m. According to official statistics harvesting of this species considerably increased after Croatia became a member of the EU due to an expansion of the market. Maximal landing of this species was around 513 tonnes in 2015 while afterwards decreed and the landing in 2019 was just 44 tonnes. This was also confirmed by scientific studies wherein 2013 recorded biomass indices were around 780 kg/km2 while in 2017 biomass indices were lower than 100 kg/km2. Although exploitation can be the main cause of O. edulis population decrease, other environmental factors that can cause natural mortality or a low recruitment rate cannot be excluded (e.g. increasing temperature, disease). Therefore, the aim of our ongoing study was to describe the current state of the oyster bed in the Northern Adriatic by analysing its reproductive cycle and occurrence of the parasites. Our preliminary results bring us one good and one potentially bad news. The good news is that all analysed samples have negative PCR tests on parasites Bonamia ostreae, Bonamia exitiosa and Marteilia refringens. Potentially bad news was that a certain portion of adult specimens showed pre- spawning oocyte atresia that could affect reproductive cycle. However, this phenomenon needs to be further investigated and our research is currently focused in that direction. In conclusion, considering the great efforts that are invested in the restoration of O. edulis habitats across Europe detection, protection and restoration of the oyster beds in the northern Adriatic are necessary. Furthermore, the results of this study will serve as a scientific baseline for future spatial-temporal regulation of the fisheries in this area.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Veterinarska medicina

POVEZANOST RADA