Occurrence of an acipenser sp. (actinopterygii, acipenseriformes, acipenseridae) specimen from lemnos island, northeast aegean sea, Greece. How many sturgeon species are actually known?

Abstract

Sturgeons are ancient and though that they were a major component of the inland fisheries globally, they are not well studied, and they face various threats like overharvesting, habitat degradation, anthropogenic interventions and others. Noteworthy, is that all European sturgeon species are threatened. Scientific community is not actually convinced on how many species, subspecies, or varieties are in fact living globally, clearly separated to each other. This controversy demonstrates at least important overlaps on their geographical distribution, maybe of genetic basis. The finding of the current study is quite unique since exhibits strong morphometric and meristic characters of two different sturgeon species Acipenser sturio and A. stellatus. The present specimen in view had 18 gill rakes (18-25 in A. sturio and 30-36 in A. stellatus) and 36 lateral scutes (24-39 in A. sturio and 30-36 in A. stellatus). Furthermore, the ratio of Snout Length / Head Length was 60.22% (≤ 60% in A. sturio, ≥ 60% in A. stellatus). Also, the present study signifies the urgent need of unified protection and conservation measures before it is too late to act.