A total of 791 elephant fish, Mormyrus rume specimens of various sizes were sampled from River Ose, southwestern N ger a. Length-weight relationship and condition factor of the M rume specimens were studied. Their standard lengths ranged from 15.0 to 45.0 cm. Mean standard length for males, females and combined sex were 27.86 cm, 30 08 cm and 28.97 cm, respect vely. The body weight ranged from 75.5 to 610.0 g Mean body weight for males, females and combined sex were 167.57 g 237.38 g and 202.48 g respect vely. Leng h-weight relat onship for males, emales and combined sex were 1.699, 2.134 and 1 990, respectively. The f sh exhibited al ometr c growth in the river. The predictive equation was log W = -0.636 + 1 99 log L. The mean condition factor varied between seasons. The mean condition for males, females and combined sex were 0.787, 0.859 and 0.823, respect vely. The cond tion factor decreased with increase in nd vidual sizes.

Qualitative and quantitative assays were conducted to determine the occurrence and distribution of digestive enzymes in different gut regions of juvenile and adult elephant snout fish, Mormyrus rume. Amylase, maltase, lactase, sucrase, chitinase, pepsin, trypsin and lipase were present in the oesophagus, stomach, pyloric caeca, duodenum, ileum and rectum at varying quantities and activities. The wide distribution of enzymes in both juvenile and adult M. rume confirms its ability to digest carbohydrate, protein and lipid portions of its diet.

No abstract

Fecundity study is important in order to evaluate the reproductive potentials of fish species. Thus, fecundity and food habits of Hippopotamyrus ansorgii (H. ansorgii) from Ogbese river were investigated. Total of 32 specimens of H. ansorgii were used. The major fishing method employed for collecting the specimens were cast and gill netting. Fecundity and food habits the fish were studied. The total lengths ranged from 14.6 cm to 22.1cm while the body weights ranged from 30.0 to 91.0 g. The food items found in the examined stomachs were rotifer, algae, insects, crustacean, detritus and plant parts but the major food items based on the ranking index were insects and crustaceans. The sex ratio of H. ansorgii was 1.13: 1 for males: females. The gonadosomatic index showed that H. ansorgii in Ogbese river uses an average of 11.69% of its body weight in egg production. Fecundity ranged from 600 to 7200 eggs with an average of 3231 eggs per female. In conclusion, H. ansorgii in Ogbese river was an omnivore and highly fecund fish.

No abstract