Addition of mussel shells enhance marine benthic biodiversity in two degraded coastal soft sediment ecosystems.

The decline in coastal shellfish populations, attributed to anthropogenic stressors such as harvesting via dredging, can deplete the seabed of vital biogenic habitat. This removal of shellfish significantly reduces habitat complexity, biodiversity, and the hard substrate required for the natural recovery of some key species. A common method for oyster restoration involves deploying oyster shell material to provide habitat and substrate for settling larval oysters.

Relative macrofaunal biomass reduced under an enriched salmon farm, Pelorus Sound, Aotearoa-New Zealand.

We compared changes in the benthos associated with discharges from a salmon farm at a low-flow location in Pelorus Sound, Aotearoa-New Zealand to the Pearson and Rosenberg model (PRM). As predicted by PRM, benthic enrichment resulted in significant increases in abundance of small, opportunistic macrofauna beneath salmon farm cages. In contrast, at reference sites we found fewer but larger, rare species.