Features of the Spatial Distribution of Different Ecological Groups of Ichthyoplankton in the Northern Part of the Centr
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ures of the Spatial Distribution of Different Ecological Groups of Ichthyoplankton in the Northern Part of the Central East Atlantic A. G. Arkhipova, * and R. A. Paka aAtlantic
Branch, Federal State Budget Scientific Institution “Russian Federal Research Institute of Fisheries and Oceanography”, Kaliningrad, Russia *e-mail: [email protected] Received August 15, 2019; revised October 14, 2019; accepted October 30, 2019
Abstract—The distribution of fishes at early development stages in a 0–100 m water layer (0–bottom) in the northern part of the Central East Atlantic (northern and southern parts of Morocco and Mauritania) is considered using multivariate analysis methods. The distribution of different ecological fish groups at their early development stages can be analyzed using data on the number of eggs and larvae of fish with certain localization patterns. Two independent ecological groups are often differentiated in the study areas: mesopelagic group (far from the coast), which includes representatives of the families Myctophidae and Gonostomatidae, and neritic (coastal) group, which includes representatives of the families Clupeidae and Sparidae. The methodology used for analyzing the material makes it possible to objectively assess the similarity and difference in the species structure and distribution features of mass fishes in their early ontogenesis. Keywords: ichthyoplankton, eggs, larvae, ecological groups, multivariate analysis methods, northern and southern parts of Morocco, Mauritania DOI: 10.1134/S0032945220040013
The waters adjacent to the northern part of the Central East Atlantic (CEA) are usually formed by subtropical and tropical water masses in the surface layer (up to 150–200 m). The Atlantic coast of Morocco (32°–21° N) is washed by waters of the Canary Current flowing southwestwards. The coastal waters of Mauritania (21°–16° N) are influenced by the northern branch of the Equatorial Counter Current in the northern direction. Quasistationary circulations are formed in areas located near the capes. Upwellings are observed on the shelf for most of the year (Domanevskii, 1998; Bernikov et al., 2002). Schooling neritic and mesopelagic fishes intensively spawn and their juveniles actively grow in this water area. Over 170 species of pelagic fish eggs and larvae are recorded in the upper 100-m layer above the shelf (Blache et al., 1970; Kalinina, 1981; Domanevskii, 1998; Bernikov et al., 2002; Arkhipov, 2015a). Areas with the largest aggregations of ichthyoplankton off the northwestern coast of Africa are linked to the dynamic processes of surface waters (vergence zones) in this region and relatively fixed (Arkhipov, 2006, 2015a). The mass representatives of the Central East Atlantic (CEA) ichthyocenosis are commercial species, such as European pilchard Sardina pilchardus, Atlantic horse mackerel Trachurus trachurus, Cunene horse mackerel T. trecae, Atlantic chub mackerel Scomber colias, and round sardinella Sardinella aurita. There are also some other commercial fish species that
are common h
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