Naslov
Intra-annual oscillation of the European anchovy, Engraulis encrasicolus (Linnaeus, 1758) batch fecundity and spawning frequency in the Eastern Adriatic Sea

Autori
Radonić, Ivana ; Zorica, Barbara ; Čikeš Keč, Vanja ; Vuletin, Vedran ; Ezgeta Balić, Daria

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

Izvornik
3rd International Congress AGE OF NEW ECONOMY AND NEW JOBS - BLUE ECONOMY AND BLUE INNOVATION Book of Abstracts / - , 2021, 65-65

Skup
3rd International Congress AGE OF NEW ECONOMY AND NEW JOBS - BLUE ECONOMY AND BLUE INNOVATION

Mjesto i datum
Split, Hrvatska, 10.10.2021. - 12.10.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
European anchovy, batch fecundity, spawning frequency, POF

Sažetak
The European anchovy Engraulis encrasicolus (Linnaeus, 1758) is one of the most important commercial pelagic fish species in the Adriatic Sea, characterised by a short life span, high growth rate, early sexual maturation, long spawning period (peaking from May to July) and high fecundity. Anchovy biomass has exhibited considerable fluctuations over the last few decades in the Adriatic and worldwide. To better understand those biomass fluctuations, we examined the inter-annual oscillation of two reproductive parameters (batch fecundity and spawning frequency) in the context of their environment within the investigated period (2017-2020). To estimate batch fecundity and spawning frequency matured ovaries of anchovies were sampled during the last four scientific surveys (those surveys were done under the umbrella of MEDITS and ESAmar projects ; surveys took place once per year, during June-July to be more precise). Collected ovaries were examined histologically to determine the presence of females with postovulatory follicles (POFs) and hydrated oocytes. The POFs were classified as day-0, day-1 or day-2 and the spawning fraction was determined as a proportion of day-1 spawning females. To avoid biases, when estimating batch fecundity (number of oocytes released per spawning) only ovaries with hydrated oocytes and without POFs were used. During each survey, the sea surface temperature and salinity were measured at sampling stations. Correlations between biotic and abiotic factors were studied and analysed throughout the investigated period (2017-2020). Results reported here contribute to the knowledge about this species and they will be useful for the implementation of the Daily Egg Production Method which should ensure more reliable values of the spawning stock biomass of anchovies in the Croatian side of the Adriatic Sea.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Biotehnologija

POVEZANOST RADA