التأثيرات البيئية على تجمع الأسماك في نهر الكرمة باستخدام برنامج Canoca

Abstract EN

The effects of ecological parameters on fish assemblage of Garmat Ali River, north of Basrah, Iraq were studied using Canoca program during November 2007 - October 2008.

A total 4913 fishes belonging to 26 species and١3 families were caught using gill net, cast net, electro-fisher, hook and lines.

Water temperature varied from 14.3oC in January to 32.5 oC in July.

Salinity ranged between 1.2 in November to 3.2 %o in July.

Transparency fluctuated from 38 cm in July to 75cm in November and pH from 7.74 in November to 8.17 in July.

Associations between fish assemblage and environmental variables were quantized by using canonical correspondence analysis (CCA).

The results revealed that the species composition can be divided into two groups, the first, consisted from eight species, were significantly correlated with both water temperature and salinity, and the second group consisted from 18 species were correlated with pH and to less extent with light penetration.

The fish fauna consisted of ten species, seven seasonal and nine occasional.

The diversity index ranged form 1.843 in September to 2.787 in Jun.

Richness index varied from 2.56 in December to 3.26 in July.

The evenness index fluctuated from 0.62 in August to 0.855 in Jun.