# Boat noise alters individual behaviors but not communication between partners in a fish-shrimp mutualism

## TL;DR

Boat noise affects individual behaviors of fish and shrimp in a mutualistic relationship but does not disrupt their communication.

## Contribution

The study reveals species-specific responses to different boat engine noises in a natural mutualistic partnership.

## Key findings

- Gobies increased burrow use during 4-stroke boat noise exposure.
- Shrimp responded more strongly to 2-stroke engine noise.
- Tactile communication between partners remained unaffected by noise.

## Abstract

Persistent noise pollution produced by boat traffic is reshaping marine soundscapes globally. Despite growing ecological concern, most studies to date have focused on individual-level effects under laboratory conditions, leaving major gaps in our understanding of how boat noise shapes species interactions in the wild. Using field-based behavioral assays, we investigate how boat noise from different engine types (4-stroke and 2-stroke) affects the mutualistic partnership between Steinitz's goby (Amblyeleotris steinitzi) and snapping shrimp (Alpheus spp.). Across 123 partnerships, we recorded behavioral responses before, during, and after noise exposure. Gobies increased burrow use during 4-stroke boat noise exposure, while shrimp responded stronger to 2-stroke noise—reflecting taxon-specific sensitivities to different noise spectra. Despite these shifts, tactile partner communication was not affected by boat noise. These findings highlight divergent vulnerabilities between species tied to different engine acoustics and emphasize the need for targeted research to inform strategies for mitigating marine noise pollution.

Boat noise disrupts how gobies and shrimp share their burrows, with each species responding differently depending on engine type. While gobies perceived the noise from 4-stroke powered boats as a greater threat, shrimp responded stronger to 2-stroke noise. Despite these shifts, their tactile communication—key to their mutualism—was robust to noise exposure. Our study highlights that engine choice can shape species-specific responses, informing better management of marine noise pollution.