Tolerance levels of redbreast tilapia, Tilapia rendalli (Boulenger, 1896) to natural suspended silt

摘要: Tilapia rendalli was exposed to various siltconcentrationsfor different exposure periods determine LC50 andsublethalconcentration ranges. The extent of damaging effects, if any,ofsuspended silt on the fish, were investigated by meansofscanning electron microscopy. values rangedbetween21 24 g l™1 and 42–48 for juveniles andadultsrespectively. concentrations tolerated testfisheswere above those found in most natural waters. resultstherefore support hypothesis that suspended is lethaltofish at higher than naturally observed insurface water. mortalities can be attributed tothecombined physical effects high andassociated reduction dissolved oxygen levels. To preventfishmortalities other impacts biota, anthropogenicactivitiesthat affect variation siltconcentrationsin surface water should carefully monitored and, wherepossible,be restricted.