THE BREEDING BIOLOGY OF CLARIAS-ALBOPUNCTATUS NICHOLS AND LAMONTE, 1953 IN SEMI-INTENSIVELY MANAGED PONDS IN THE FLOODPLAIN OF THE RIVER ANAMBRA, NIGERIA

In ponds in the floodplain of the River Anambra, Nigeria, Clarias albo punctatus matured after the first year when they were 101-150 mm in to tal length. Gonad development was more rapid in males than in females. The breeding season lasted from March to September, and recruitment o f the clariids into the artisanal fishery began from the latter month. The number of oocytes in both ovaries ranged from 1974 to 9310. Fecun dity-weight relationship was linear and positively correlated: Y = 145 1.64 + 77.19x, r(2) = 0.82. Spawnable oocytes, which constituted over 91% of gonad weight, ranged from 1.05 to 1.75 mm in diameter. A minor and major communal spawning involving Clarias macromystax, C. agboyien sis and C. albopunctatus took place in the inundated grassy areas of t he floodplain. Migration of 4-month-old juveniles towards the main riv er or floodplain ponds, which appeared to be triggered by current spee d in the spawning ground, occurred during the night and in groups.