Habitat Use and Movement Activity of Neolissochilus soroides and Channa lucius during Post Inundation of Tembat Reservoir, Hulu Terengganu

Abstract

The drastic changes in hydroelectric reservoir development created a completely new ecosystem that affects the river, particularly in the inundated area. In this study, five Neolissochilus soroides and Channa lucius were surgically implanted with a unique coded acoustic transmitter to observe the habitat utilisation and movement activity in Tembat Reservoir after the inundation process. All of the individuals were released into the transition zone of the reservoir and observed using passive and active acoustic tracking devices from April to December 2018. Kruskal-Walis test showed no significant difference between the average size of core area for N. soroides and C. lucius, x2(1) = 1.320, p = 0.251. The home range also showed a similar result for N. soroides and C. lucius where there was an insignificant difference, x2(1) = 0.273, p = 0.602. However, duration wise, N. soroides spend more time in the transition zone, R1 (M = 2.71 hrs, SE = 0.38), and C. lucius in the riverine zone, R5 (M = 7.14 hrs, SE = 6.13) and R6 (M = 3.85 hours, SE = 6.36). From the active tracking survey, PCA identified three (62.32%) and four (71.19%) components with eigenvalues greater than 1 for N. soroides and C. lucius, respectively. Three most important habitat parameters for N. soroides were the size of river (r = 0.97), existence of canopy cover (r = 0.77), and substrate type (r = 0.79).While, for C. lucius were mesohabitat type (r = 0.79), distance to riffle (r = 0.97), existence of canopy cover (r = 0.90), and elevation (r = 0.90). A 24-hour movement frequency analysis for both species revealed two active hours of movement at dusk and dawn for both species. From the study, it is known that N. soroides and C. lucius respond differently towards the inundation of the reservoir. The findings in this study can be implemented for effective aquatic management and conservation plan to ensure sustainable dam development.