Composition and diversity of ichthyoplankton in the Boka Kotorska Bay (South Adriatic Sea)

Abstract

Variation in the diversity of ichthyoplankton was analyzed from samples collected during threeyear cycle in Boka Kotorska Bay. Samples were collected using Calvet (modified PairOVET) plankton net at 18 stations, from July 2006 through January 2009. Families with most numerous species were Engraulidae, Sparidae and Labridae. Investigation shows dominance of anchovy (Engraulis encrasicolus), Mediterranean rainbow wrasse (Coris julis) and annular sea bream (Diplodus annularis) during the summer. During the winter, dominant species were sardine (Sardina pilchardus) and Atlantic mackerel (Scomber scombrus), while during the spring dominant species were anchovy, annular sea bream and white sea bream (Diplodus sargus). Spawning of most pelagic fish species in Adriatic Sea starts in spring, and progress during spring and summer months. Therefore, the highest number of species was found in these months, while the lowest number of species was during autumn and winter surveys. Eggs and larval stages of 35 species was determined, while the diversity analysis showed a significant degree of diversity in certain stations where the sea currents were probably the strongest. Diversity of ichthyoplankton communities was analyzed applying two diversity indices: Shannon index (H') and Simpson index (D). Diversity analysis was performed for each of the 18 investigated stations during the tree-year research, while influence of environmental factors on presence of some ichthyoplankton species by seasons was tested with Canonical Correspondence Analyses (CCA).