Invasive Species Compendium

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Abstract

Comparison of functional responses between exotic species Lepisosteus oculatus and native species Channa maculata.

Abstract

In order to evaluate the predation efficiency of exotic fish gars on local fish resources and the difference in food consumption with local carnivorous fishes, the predation of carp (Cirrhinus molitorella), Guangdong bream (Megalobrama terminalis) and grass carp (Lepisosteus oculatus) was studied . The functional response of Ctenopharyngodon idellus (Ctenopharyngodon idellus) was studied experimentally, and compared with that of the similar carnivorous fish Channa maculata (Ctenopharyngodon idellus) . The study analyzed the types of functional response of gar and snakehead, established a functional response curve, estimated the parameters related to resource consumption rate, and combined the functional response model and food conversion efficiency to simulate the population growth trend of the two species of fish. The results showed that the functional response types of gar and snakehead were Type-II; there was no significant difference in the attack rate (P =0.383) and food processing time (P =0.663) of the two predators, indicating that the two predators There is no significant difference in the unit resource consumption rate; the relative growth efficiency of the gar is significantly higher than that of the Channa (P <0.05), but the food conversion efficiency is not significantly different (P = 0.132); the population of the gar grows faster than Channa snakes have a higher stable population density. The research provides a basis for systematically assessing the ecological impact of exotic fish gar, and the method of quantifying functional response adopted can provide reference and reference for the assessment of the ecological impact of other exotic fishes.