Effects of Turbidity and Habitat Complexity on the Foraging Behavior of the Black Bullhead (Ameiurus melas)

Abstract

The role of vertebrate scavengers in nutrient flow of aquatic ecosystems has recently been emphasized. Evidence is accumulating that scavenging is an alternative tactic for certain predatory fish, but their foraging choices between scavenging and predation under varying environmental conditions have not been studied. In this experiment, we presented black bullheads, Ameiurus melas (Rafinesque, 1820), with both live and carcass prey of tubenose gobies, Proterorhinus semilunaris (Heckel, 1837), in aquaria with varying levels of turbidity and habitat complexity. Our findings revealed that black bullheads exhibit higher consumption of carcass prey in complex habitat and clear water condition. We also provide evidence of the active predatory behavior displayed by black bullheads, as a greater consumption of live prey was observed in simple habitat and turbid water. We did not find any relationship between individual exploratory behavior and the choice between carcass and live prey in black bullheads. Our results suggest that the choice between scavenging versus predatory foraging strategy under varying environmental conditions is influenced by the behavior of both consumer and prey. The ability of black bullheads to adapt their foraging strategy in different environments may contribute to their widespread success as an invasive species.

Keywords:

• prey choice
• predation
• scavenging
• foraging strategy
• freshwater trophic interactions

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Funding

The research presented in the article was carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022 00008 project, co-funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA, NP2022-II3/2022), and the 243/1/2021/HF [Balatoni halfajok halegészségügyi monitoringja (Survey of health status of fishes of Lake Balaton)] project. IC was supported by the OTKA PD 138296 grant (National Research, Development and Innovation Office – NKFIH).

Ethical Statement

All procedures involving the handling and treatment of fish were in accordance with the permit for the delivery and use of aquatic animals for scientific purposes (permit reg. no.: VE-I-001/01890-3/2013, valid between 22 August 2013 and 21 August 2023, issued by the Food-Security and Animal Health Directorate, Governmental Office of Veszprém County, Hungary).

Contributions

BP and TE conceived the study. All authors designed the methodology. BP, AS, and IC carried out the experiment. AS and BP analyzed the data, created the figures, and wrote the initial draft of the manuscript. All authors contributed critically to the drafts.

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.