PHYSICO-CHEMICAL PARAMETERS AND FISH SPECIES DIVERSITY OF DADIN-KOWA RESERVOIR, GOMBE STATE, NIGERIA
PHYSICO-CHEMICAL PARAMETERS AND FISH SPECIES DIVERSITY OF DADIN-KOWA RESERVOIR, GOMBE STATE, NIGERIA
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Date
2017-03
Authors
YERIMA, RASHIDA
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Abstract
The study was conducted to determine the monthly variation in some physico-chemical parameters, fish species composition and diversity, and condition factor of the resident fish species in Dadin-Kowa reservoir. The water electrical conductivity and total dissolved solids, and pH were measured by Hanna conductivity meter model EC 215 and pH meter model H198107. Other parameters which include: water temperature, waterdepth, transparency, dissolved oxygen (DO), biochemical oxygen demand (BOD), carbon dioxide and water hardness were measured using standard methods. The fish samples were identified using standard descriptions keys. The Shannon Weiner diversity index was used to determine the diversity of fish species in the reservoir. One-Way Analysis of Variance (ANOVA) was used to test for significant differences in species diversity among stations and Duncan’s Multiple Range Test (DMRT) was used to separate the means where significant differences exist. Student’s T – test was used to compare the variation in physico-chemical parameters and fish diversity in dry and wet seasons. There was high significant (P ≤ 0.05) variation in the physico-chemical parameters with months in the reservoir except for water depth, carbon dioxide and hardness. There was high positive association between BOD and DO (r =1.00) and between carbon dioxide with EC and TDS (r = 0.80). Temperatures showed moderate significant positive relationship with carbon dioxide, BOD and DO. A positive and significant association was observed between TDS and EC. Water depth was found to significant negative association with temperature, EC, BOD, TDS, DO and carbon dioxide. Of the total 690 fish sampled, thirty (30) fish species representing eleven (11) families were identified. The family Mormyridae had the highest number of species (6) followed by the family Mochokidae (5) then the families Alestidae, Cyprinidae,Clariidae and Claroteidae while the families Malapteruridae, Polypteridae and Schilbeidae had the least number of species each. The highest percentage was in the family Mormyridae with 20.0% fish followed by
Mochokidae with 16.7%. The family Malapteruridae, Polypteridae and Schilbeidae with 3.3% had the least catch. Of the total of 690 fish sampled, the highest percentage of 18.99% fish belongs to the genus Petrocephalus, followed by Heterobranchus with 16.23%. The least catch was in the genus Malapterurus with 0.72% fish. Out of total fish species sampled Mormyropsanguilloides, Clariasanguillarisand Schilbemystus had 14.5%, 8.7% and 8.6% respectively of the fish composition. Labeosenegalensis and Synodontisbudgettihad 6.9% and 5.8% respectively. While the remaining fish species had percentage occurrence of less than 5%. There was significant variation (P ≤ 0.05) in the number of fish species sampled monthly in the reservoir. The highest diversity index of 2.056 was in the family Cyprinidae. The least index value of 1.32 was obtained in the family Claroteidae. The degree of evenness of the families was lowest (0.8296) in Alestidae and highest (0.976) in Cyprinidae. The family Malapteruridae with the least individuals had the least dominance while the family Cichlidae had the highest value of 0.188. The genera Hyperopisus, Mormyropsand Malapterurushad the lowest indices while Petrocephalus, Clarias, Barbusand Oreochromishad the highest number of fish species. Highest condition factors of 1.1 and 1.09 were observed in Brycinusmacrolepidotusand Malapterurusminjiriya respectively. Lower values of 0.31 and 0.30 were obtained in Chrysischthysnigrodigitatusand Momyropsanguilloides respectively. This indicates that the fish species in this study showed good physiological state and health condition.The study revealed marked monthly variation in the physicochemical factors, rich fish composition with important economic species and variation in condition factor of highly diversified fish community structure in the reservoir. It is hereby recommended that regular monitoring of the physicochemical parameters of water and sustainable management of the fisheries resources of the reservoir be encouraged.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA,
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF MASTER OF SCIENCE (M.SC.) DEGREE IN FISHERIES
DEPARTMENT OF BIOLOGY,
FACULTY OF LIFE SCIENCES,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
PHYSICO-CHEMICAL PARAMETERS,, FISH SPECIES DIVERSITY,, DADIN-KOWA RESERVOIR,, GOMBE STATE,, NIGERIA