Quantitative Distribution of the Flying Fish (Exocoetidae), Marine Mammals, Birds, and Sea Turtles in the Northern Part of the Central Atlantic Ocean (Results Obtained in the Research Cruises nos. 43–45 of the R/V “Akademik Nikolaj Strakhov”)

Abstract

The results of visual assessments of the flying fish (Exocoetidae), marine mammals, birds, and sea turtles, carried out mainly in the northern part of the Central Atlantic Ocean both during the ship was under way and at stations, are presented. Schematic maps of the quantitative distribution of the detected animals and of the specific biomass of the flying fish are provided. In terms of abundance and biomass of the flying fish, the studied region of the Atlantic south of 30° N is one of the most productive in the World Ocean, no signs of decreasing productivity have been found when compared with data obtained earlier. Tremendous abundance of gulfweed (Sargassum) in the study area is expected to have a positive effect on the abundance of birds and four-winged flying fish (subfamily Cypselurinae); at the same time, it apparently had a negative impact on the abundance of two–winged flying fish (genus Exocoetus). As a result, four-winged flying fish began to significantly predominate in the study area replacing the two-winged flying fish that dominated by abundance for almost a century. The relationships between the abundance of the flying fish and birds and some environmental parameters have been studied. An attempt has been made to assess the influence of various environmental factors on the quantitative distribution of the flying fish and birds using mathematical models.