Of the birds, three are Caucasian endemics: Caucasian grouse (Tetrao mlokosiewiczi), Caucasian snowcock (Tetraogalus caspius) and Caucasian warbler (Phylloscopus lorenzi). Among these, around 600 (14 per cent of all species) are Caucasus endemics and 300 (9 per cent of all species) are endemic to Georgia. Until the mid-1970s, the Black Sea was characterized as a highly productive ecosystem at all trophic levels, but by the 1990s it had degraded to an ecosystem with a low biodiversity dominated by a “dead-end” gelatinous food web.