The Results of Zmiinyi Island (Black Sea) Coastal Waters Ichtiofauna Monitoring in 2016-2017

Abstract

Purpose. To study the state of ichthyofauna in the Zmiinyi Island coastal waters in 2016-2017. Methods. Standard methods of ichthyofauna sampling, determination, abundance and biomass estimation. Results. During the period of studies, 68 species of marine, brackish-water and freshwater fish were found in the Zmiinyi Island area belonging to 18 orders, 41 families and 55 genera. The biggest number of taxa belongs to Perciformes order. The representatives of this order make one-half of all the species found near the island. Indicators of ichthyofauna species diversity in the Zmiinyi Island area were gradually decreasing in the period from 2003 to 2009. In 2015-2016 all those indicators grew significantly. Biodiversity level (Shannon index values calculated coming out of number) in 2016 varied from 0.86 to 3.06 making in the average 2.06; in 2017 – from 2.40 to 2.54 making in the average 2.47. Minimal values of biodiversity indicators were registered in the end of autumn and in winter, maximal – in May-June. In the Zmiinyi Island coastal waters 30.9% of all the fishes registered in the Black Sea were found. The fishes caught near the island belonged to 5 ecological groups. The basis of ichthyofauna in the area was formed by marine fish species – 52 species (76.5 % of the total number of species). Most of species (54 species or 89.4%) were bottom-dwelling or near-bottom. Pelagophylic and protecting species prevailed and their numbers were almost equal (24 species or 35.3% and 23 species or 33.8% respectively). On the type of feeding, predatory (37%) and benthos-eating (33%) species prevailed. Out of 68 species found in the island area, 16 species are included into the Red Book of Ukraine, 22 species – into the Black Sea Red Data Book, 7 species – into the IUCN Red List. More than one-half of the species registered in the area (36 species or 52% of all the species) have a protected status. Сonclusions. Results of analysis of biodiversity, structural characteristics and taxonomic composition of ichthyofauna in the Zmiinyi Island coastal waters have been presented. Seasonal dynamics of its number and biomass has been studied. The results of the analysis of some aspects of ecology and biology of the main mass species of fish are presented. Recommendations are given to improve monitoring of the ichthyofauna of coastal waters. Quality of bottom communities monitoring in the Zmiinyi Island coastal waters can be increased significantly by development and implementation of non-contact low-budget video-monitoring methods to solve the problem of fish stock and biodiversity studying in inaccessible areas. It is anticipated that the method developed will help high precision assess of fish stock in inaccessible shelf areas where application of other methods is connected with technical difficulties, high cost and can lead to unreliable results. Elaboration of the method aimed at development of video materials received computer processing algorithms will significantly simplify the analysis of the data collected.