Analysis on fish kill along University of Lagos Lagoon beach, Southwestern, Nigeria
Abstract
Investigation on the mass mortality of fishes (Sarotherodon melanotheron) along the University of Lagos Beach Off Lagos Lagoon was carried out for six months (February to July 2016). Monthly collection of water and fish samples were done, Physio-chemical analysis of the water samples and biological analysis (mycological inclusive) of the collected fish samples were also carried out. The highest number of fish kills was recorded in February (35) and the lowest number (3) was recorded in July. The mean values for the physico-chemical characteristics in the three stations included: air temperature 24.7±0.55⁰C; water temperature 27.1±0.3⁰C; salinity 24.7±1.3‰; pH 6.7±0.1; dissolved oxygen 5.2±0.3mg/L; and hardness 10296±3962mg/L. The changes in water temperature (25.50C – 290C), D.O (2 – 6.6mg/L), salinity (19 ‰ – 29 ‰) and hardness (148 – 25000mg/L) affected the number of fish mortality in Lagos Lagoon. It was noted that the number of fish mortalities increased with increasing water temperature, salinity, and hardness. Mycological examination of infected fishes revealed the presence and loads of two fungal species namely: Saprolegnia sp. and Pythium insidiosum. The parasitic examination revealed the presence of the protozoan (Trichodina sp. and Myxobolus sp.) and platyhelminths parasites (Diphyllobothrium latum). Diphyllobothrium latum had the highest prevalence (0.9). It was concluded that there’s need for further studies to elaborate these findings.
