The ichthyoplankton assemblage along the eastern Adriatic Sea during two consecutive summers

Two ichthyoplankton surveys (June – July 2019 ; 2020) were conducted along the eastern side of the Adriatic Sea (Croatian fishing ground). Ichthyoplankton samples were obtained by standard vertical plankton tows using a WP2 sampler (mouth opening, 0.255 m2 ; mesh size, 0.200 mm) and preserved in 96% ethanol. In the laboratory, ichthyoplankton was isolated under the binocular and its taxonomy was determined using DNA barcoding with cytochrome c oxidase subunit I (COI). Overall, 1381 fish eggs and 407 larvae were collected and they belonged to 39 fish taxa. Quantitatively, the dominant taxa was Engraulis encrasicolus (L.). Biodiversity indices (Species richness (S), Simpson’s Index of Diversity (D), Shannon-Wiener Index (H), Evenness (E), Jaccard Index (J)) pointed out that samples obtained within two summers were quite similar (J=81.8%).