PHYSICO–CHEMICAL PARAMETERS AND BENTHIC MACRO-INVERTEBRATE COMMUNITIES OF CALABAR RIVER, NIGERIA

Abstract

A study was conducted to assess the influence of physicochemical parameters on the abundance and distribution of benthic macro–invertebrates in Calabar River (latitude 04⁰ 55’ 55” to 05⁰ 02’ 50”N; longitude 008⁰ 16’ 35” to 008⁰ 18’ 13.8” E). Five sampling stations labeled stations 1, 2, 3, 4 and 5 respectively, were chosen along the river course. Physicochemical parameters were measured using their respective meters while macro–invertebrates were collected using a Van Veen grab and identified under microscope. Diversity indices; Margaleaf’s (d), Shannon’s (H) and Pielou’s (E) were calculated using their respective formulae. All physico–chemical parameters differed significantly across sampling stations with the exception of temperature and pH. Temperature was lowest (27.52⁰C) at station one and highest (30.30⁰C) at station five while the lowest and the highest average pH were 6.0 at station one, and 6.40 at station three respectively. The lowest DO value (3.10 mg/l) was recorded at station five while stations three and four had the highest value (3.95 mg/l). Lowest and highest BOD were 1.05 mg/l at station one and 2.05 mg/l at station three respectively. TSS was lowest (10.60 mg/l) at station four, and highest (29.05 mg/l) station five while TDS was lowest (19.70 mg/l) in station one and highest (40.80 mg/l) at station five. 5866 macro–invertebrates belonging to different taxa were identified.  Species abundance and diversity indices were generally low, indicating stress in the environment