Morphobiological features of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner) (Scorpaeniformes, Cottidae) from Sakhalin

Data on the flathead sculpin Megalocottus platycephalus taeniopterus from different regions of Sakhalin are provided. Based on analysis of the morphological material, the estimates of taxonomically significant characters of the northern and southern subspecies are clarified. They include the relative length of the lower jaw, the extent of development of postorbital and occipital tubers, the coloration of pectoral fins, the shape of free ends of ventral fin rays, and their relative length and coloration in females. The habitats of M. platycephalus taeniopterus are considerably attributed to the desalinated sites of coastal waters. In the areas of eastern Sakhalin, its individuals stay in brackish water lakes and lagoons for a considerable part of their life; some individuals migrate to coastal waters for feeding in summer. Considerable differences are observed between populations in the life span, rate of growth, and the age of maturation of individuals. In the regions of eastern and western Sakhalin, the pattern of feeding of M. platycephalus taeniopterus differs considerably: in eastern regions, it is a clearly pronounced predator, and in western regions, it feeds mainly on invertebrates.