Species-specific drivers explain fish feeding and individual niche variation

Area of Science:

• Ecology
• Ichthyology
• Environmental Science

Background:

• Trophic ecology is influenced by complex environmental and biological interactions.
• Limited studies explore trophic ecology across multiple fish species with diverse environmental variables.

Purpose of the Study:

• To analyze diet and niche variation in fish communities across five protected areas in the northern Iberian Peninsula.
• To examine fish community responses to environmental and biological gradients.
• To identify drivers of fish feeding behavior and individual specialisation.

Main Methods:

• Multiple regression analyses were used to assess diet and niche variation.
• Fish communities were studied across five protected areas in the northern Iberian Peninsula.
• Environmental and biological gradients were analyzed in relation to fish feeding strategies.

Main Results:

• Both environmental and biological drivers significantly influence fish feeding behaviour and individual specialisation, with species-specific effects.
• Benthic macroinvertebrate density and fish density were key factors shaping feeding strategies.
• Benthic macroinvertebrate density positively affected niche specialisation in brown trout and Pyrenean stone loach, but negatively impacted Pyrenean minnow.

Conclusions:

• Intrinsic factors (feeding behaviour, ontogeny) and extrinsic factors (macroinvertebrate density, fish density) determine fish feeding strategies.
• Conservation efforts should focus on increasing habitat heterogeneity and promoting benthic macroinvertebrate production.
• Findings provide insights into species-specific habitat needs and fish feeding requirements for conservation and restoration.