This paper was conducted to identify fish species, to see distribution of fish commecial fishing and to determine species composition between January 2006 and December 2006 in lake Ulua-bat (Apolyont). Totally 21 fish species belong to 9 families were identified. These species were Cyprinus carpio (Linnaeus, 1758); Carassius gibelio (Bloch, 1782); Vimba vimba (Linnaeus, 1758); Alburnus alburnus (Linnaeus, 1758); Blicca björkna (Linnaeus, 1758); Scardinius erythrophthalmus (L., 1758); Rutilus rutilus (L., 1758); Barbus plebejus Bonaparte, 1832; Tin-ca tinca (Linnaeus, 1758); Chalcalburnus chalcoides (Güldenstaedt, 1772); Siluris glanis Lin-naeus, 1758; Esox lucius L., 1758; Alosa maeotica (Grimm, 1901); Mugil cephalus L., 1758; Sygnathus sp. L., 1758; Anguilla anguilla (Linnaeus, 1758), Knipowitschia sp. (Iljin,1927); Rhodeus sericeus (Jordan & Thompson 1914); Pseudorasbora parva (Temminck&Schlegel, 1846); Gobius fluviatilis Pallas, 1811 and Cobitis sp. L., 1758. In addition Astacus leptodacty-lus Esch. 1823 from the crustacea was identified in this lake. The relative abundance of B.björkna (7.97) was higher than the other species. This species was followed by C. gibelio (.54), R.rutilus (.77) ve E.lucius (.40). The relative abundance of highly economic species were found to be %2.83, %0.13 and %0.07 for C.carpio, M.cephalus and S.glanis, re-spectively. In addition, it was determined that a total of 642 500 kg fish were caught in Lake Uluabat in 2006.