Chromosomal Aberration In Fish Inhabiting Polluted Aquatic System: A Review
Anyaele UKA Ph D
Department of Fisheries and Aquatic Resources Management, College of Natural Resources and Environmental Management. Michael Okpara University of Agriculture, Umudike.
Keywords: Aneuploidy, Conservation, Cytotoxicity, Environment, Karyology
Abstract
Occurrence of chromosomal aberration in fish as incidence of aquatic pollution was reviewed. Changes in chromosome number and structure as evidence of aberration consequent upon exposure to contaminated water were documented. Methods reported on karyotyping to examine fish chromosome for aberration included in-vivo tissue culture, in-vitro squashing techniques and suspension of tissue cells undergoing mitosis. Agricultural and industrial effluents were common contaminants implicated in aquatic pollution. Short time exposure of fish to agricultural effluent such as butachlor (acetamide, C17H26ClNO2) can interfere with cellular activities in fish at genetic level concomitant to damage on chromosome. The damage on fish chromosome depends on duration of exposure to the contaminant. Requisite of assessing chromosomal aberration in planning fish conservation and aquatic system preservation was elucidated. The report recognized cytogenetic study as a useful tool in providing information on evolutionary and taxonomic studies. It is also relevant in genetic improvement of commercial fish stocks. The study posits the need for a standardized mechanism to monitor changes in the genetic diversity of fish populations and supported the call that taxonomic grouping of fishes by external and internal morphology should be authenticated with cytogenetic examination. This is necessary for accurate definition of genetic improvement in fish species and for application of appropriate research methodologies in fish conservation programme.