Influence of Local Habitat and Climatic Factors on the Distribution of Fish Species in the Tonle Sap Lake

Bunyeth Chan,Sovan Lek,Zeb Hogan,Sébastien Brosse,Peng Ngor

doi:10.3390/w12030786

Abstract

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the lake remain poorly understood. Using commercial fishing lot catch data from 1994/1995 to 1999/2000, fishing seasons and environmental data (land cover and bioclimatic variables), we describe spatial distribution of the eight most commercially important fish species, and investigate the effects of environmental factors on their distributions in the TSL. We found a strong variability in fish biomass across areas and between species. Specifically, Channa micropeltes was most abundant in the southern and northern sections of the TSL. Channa striata and Trichopodus microlepis were more common in the northern part of the TSL. Cyclocheilos enoplos, Barbonymus gonionotus, Pangasianodon hypophthalmus, and Gymnostomus spp. were abundant in the southern areas of the TSL while Phalacronotus spp. were abundant in few areas in both the north and the south. Flooded forest positively explained the variation in the biomass of P. hypophthalmus, C. striata, C. enopolos, and Phalacronotus spp. Likewise, the lake’s open water positively affects the biomass of P. hypophthalmus, C. enopolos, and Phalacronotus spp., while the agricultural field negatively impacts Gymnostomus spp. biomass distribution. We also found that some areas consistently hosted high fish biomass (e.g., lot 2, Kampong Thom; lot 6, Pursat; lot 2, Battambang, etc.). We, therefore, suggest that fisheries management and conservation planning focus on those areas, considering those areas significance as core fish habitat and important for catching fish.

Highlights

The Mekong River is the largest river in Southeast Asia and covers a drainage area of 795,000 km2 [1].It lies within the Indo-Burma biodiversity hotspot [2] and is the second most diverse river system in the world, after the Amazon River [3,4]
C. enoplos, B. gonionotus, P. hypophthalmus, and Gymnostomus spp. had their high biomass levels distributed from the central to the most southern section of the lake
Determining the spatial distribution of fish species and drivers affecting their distribution patterns are of crucial importance for fisheries management and conservation actions

Summary

Introduction

The Mekong River is the largest river in Southeast Asia and covers a drainage area of 795,000 km2 [1].It lies within the Indo-Burma biodiversity hotspot [2] and is the second most diverse river system in the world, after the Amazon River [3,4]. The Mekong River is the largest river in Southeast Asia and covers a drainage area of 795,000 km2 [1]. A substantial part of the Mekong fishery yields come from the Tonle Sap. Lake (TSL), the largest natural inland lake in Southeast Asia [1]. Lake (TSL), the largest natural inland lake in Southeast Asia [1] This lake is the world’s fourth most productive inland fishery [4] and its fisheries resources represent approximately 60% of Cambodia’s total annual production of inland capture fisheries of 767,000 metric tons [7]. The TSL, plays a crucial role in supplying fish products and protein to nearly two million people living in and around the TSL that rely on the fisheries as their primary food and economic resources [8]. The TSL fisheries account for 60% of the total protein intake of approximately 15 million Cambodian people [8,9]

Methods

Results

Discussion

Conclusion