Trawl disturbance on benthic communities: chronic effects and experimental predictions

Area of Science:

• Marine Ecology
• Fisheries Science
• Benthic Ecology

Background:

• Bottom trawling significantly impacts marine ecosystems, but long-term, chronic disturbance effects are understudied.
• Otter trawling for Norway lobster (Nephrops norvegicus) is a common practice in muddy habitats.

Purpose of the Study:

• To investigate the effects of chronic otter-trawl disturbance on benthic macrofauna in the northeastern Irish Sea.
• To assess the relationship between fishing intensity and impacts on infauna and epifauna.

Main Methods:

• Studied benthic macrofauna along a gradient of otter-trawl fishing intensity.
• Analyzed infauna and epifauna abundance, biomass, and species richness.
• Examined changes in community composition.

Main Results:

• Chronic otter trawling negatively affected infauna abundance, biomass, and species richness.
• Epifauna abundance and species richness were significantly reduced, but biomass was unaffected.
• Trawl disturbance caused significant shifts in benthic community composition.

Conclusions:

• Otter-trawl impacts are cumulative and can profoundly alter benthic communities and marine food webs.
• Short-term experimental data may not accurately predict ecosystem-level, long-term effects.
• Understanding chronic trawling effects is crucial for ecosystem-based fisheries management.