1143 / 2024-09-20 15:08:41

Research on the ecological and growth impacts of hybrid grouper (Epinephelus fuscogutatus♀ × E. lanceolatus♂) on coastal groupers based on interspecific ethology

invasive species

With the development of aquaculture, cultured fish that escape into the wild intentionally or unintentionally can interact extensively and diversely with wild fish, and these ecological and genetic interactions can be either positive or negative. To investigate whether the widely cultured marine fish, the hybrid grouper (Epinephelus fuscogutatus♀ × E. lanceolatus♂), exhibits significant interactions with commonly occurring coastal groupers after escaping into the wild environment, this study examines three aspects: territorial competition, feeding competition, and co-culture growth of the hybrid grouper.

The results indicated that: (1) In the study of territorial competitiveness between the hybrid grouper and E.awoara as well as E.akaara, the attack level of the hybrid grouper was significantly higher than that of E. awoara (P<0.01) and E. akaara (P<0.01). Additionally, there was no significant difference in the attack level of the hybrid grouper when acting as an intruder or an intruder-been. (2) Regarding individual feeding behavior among different species, individual hybrid grouper were able to quickly adapt to live prey within a short period (P<0.01). There is a highly significant difference in the maximum feeding capacity between the hybrid grouper and E. akaara (P<0.01). Furthermore, body weight as a covariate also significantly influenced the maximum feeding capacity. (3) In the study of feeding competition between the hybrid grouper and E. akaara, species and the number of repeated days had a highly significant impact on individual feeding intake during paired competition (P<0.01). Concurrently, the feeding efficiency of the hybrid grouper towards live prey was significantly higher than that of E. akaara (P<0.01). (4) In the mixed culture of the hybrid grouper and E. akaara, significant differences in growth were observed between the two species (P<0.01), with the hybrid grouper exhibiting a higher specific growth rate than E. akaara. Specifically, the specific growth rate of E. akaara in the mixed culture group was significantly lower than that in the control group, while no significant difference was observed in the specific growth rate of the hybrid grouper between the mixed culture and control groups. 

These findings further reinforce the hypothesis that the escape of the hybrid grouper into the wild can exert negative ecological and growth impacts on coastal groupers, thereby aiming to provide a certain degree of theoretical support for future research on biological invasions of marine fish species.