The Spatial Variation of &lt;em&gt;Mugil cephalus&lt;/em&gt; in the Negombo Estuary in Relation to Physico-chemical Parameters

B R C Mendis,H M P Kithsiri,M M M Najim,Lahiru Udayangana

doi:10.4038/cjmr.v5i1-2.54

Abstract

Analysis of physico - chemical parameters gives an insight to the spatial distribution of Mugil cephalus in Negombo estuary. The present study was carried out to the spatial distribution of Mugil cephalus that is governed by the physico - chemical parameters in bottom overlying surface water in Negombo estuary, Sri Lanka. Samplings at selected sites were done during one year study period from January 2017 to December 2017. During this study, fish (Mugil cephalus) and water samples were collected at Sea mouth, Duwa, Pitipana, Munnakkaraya, Dungalpitya, Dandugam Oya and Katunayake sites. Physico - chemical parameters such as the water temperature, salinity, pH, DO, electrical conductivity, BOD, COD and nutrients levels in the bottom overlying water were measured and analyzed using employing standards methods. The results revealed that salinity, pH, EC, BOD and nutrient levels were below the maximum permissible limits of the discharge industrial wastewater quality standards of the Central Environmental Authority (CEA), Sri Lanka. The COD levels were higher than the permissible threshold limits. The seasonality in the physico - chemical levels of water were observed with a peak period from May/June and October/November, which apparently coincided with the inter monsoonal periods of the island.

Highlights

Estuaries are transitional environments between rivers and the sea, and are characterized by widely varying, localized and often unpredictable adverse hydrological and physico - chemical environmental conditions (Day et al 1989)
The results of the physico - chemical parameters of the bottom overlying surface water, at seven sampling sites during the study period are tabulated in Table 2, along with the statistical analysis of variance (One - way ANOVA) of each parameter
Increasing human populations and economic development have contributed to the worsening in water quality, including periodic accumulation of metals from brackish water estuary (Zhang et al, 2015)

Summary

Introduction

Estuaries are transitional environments between rivers and the sea, and are characterized by widely varying, localized and often unpredictable adverse hydrological and physico - chemical environmental conditions (Day et al 1989). Water pollution is a serious environmental problem in the Negombo estuary. It is the degradation of the quality of water that renders water unsuitable for its intended purposes. Coastal habitats are highly vulnerable to degradation These destructed habitats have directly or indirectly negative impact on the marine biodiversity and threat to the well-being of human. The present study, was carried out with a view to investigate how the spatial distribution of gray mullet in a tropical estuary in Sri Lanka is governed by localized physico chemical variations within the estuary. This study aimed at to identify the key physico - chemical parameters that govern the spatial variation of this economically valuable fish in the estuary

Objectives

Methods

Results

Conclusion