Simultaneous paired fishing comparison of modified codend against conventional codend was done with shrimp beam trawl in nearshore sea off Lagos, Nigeria. The modified codend was designed to reduce by-catch and was made by incorporating square mesh panel at anterior bunt. The result showed that the square mesh codend significantly reduced the by-catch of juvenile fishes up to 39.35% (T-test, P < 0.05; 0.01) with no significant loss (2.9%) in the quantity of the target shrimps Nematopalaemon hastatus (P < 0 .05; 0.01). Commercially important by-catch species having a total length range of 11 to 30cm were retained by the square mesh codend, while those with total length of 4 – 10cm were highly reduced eg; Pseudotolithus elongatus (43.96%, P < 0.05, 0.01), P. senegalensis (49.03%, P < 0.05; 0.01), P. typus (36.29%, P< 0.05; 0.01), Ilisha africana (39.09%, P< 0.05; 0.01), Pentanemus quinquarius (41.02%, P