CROATIAN FAUNA 2009 - VISOVAC GOBY

Visovac Goby - Latin Knipowitschia mrakovcici Miller, 1990. (nomen nudum) Foreign names: Visovac Goby (English); Visovac Grundel (German) The Visovac Goby occurs only in Croatia, in Visovac Lake on the Krka river. This fish was named after a Croatian ichthyologist, Professor Milorad Mrakovčić, Ph.D., who discovered and recognised it as a new species in 1989. The Visovac Goby has the elongated body and laterally flattened to the tail. There are few scales, only on the sides and the tail. Males are slightly bigger and heavier than females on average and have more than 10 transversal stripes on the sides. Dimorphism is very visible during the spawning season, when the males have darker heads and fins. The Visovac Goby can reach 45 mm in length. The information about the biology of this species is very sparse. The spawning season ranges from early spring to September, and the reproductively mature population spawns several times during that period. The male makes a nest in which it stays during spawning and after spawning it protects it aggressively, defending the ova until hatching of the fry. The Visovac Goby feeds on nutrients found on the bottom, mostly small water invertebrates. Its life span is short. The Visovac Goby is a demersal, freshwater fish inhabiting the silty, sandy and gravel bottom of Visovac Lake on the Krka river. It has a small movement range. Due to its exceptionally limited habitat, the Visovac Goby belongs to the category of endangered species, sensitive to eutrofication, i.e. the quantity of nutrients in the water, pollution and all other changes in its habitat. According to the IUCN Red List, this species is Endangered (EN) in Croatia. Pursuant to the existing protection based on the law, the Visovac Goby is a strictly protected species.