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Oysters to return to the River Hamble

Work takes place on the Solent

Foundations for the largest restoration reef in the Solent have been laid, as part of the multi-million pound Solent Seascape Project to restore marine habitats across the region.

Ocean conservation charity Blue Marine Foundation laid a thin veneer of shingle mixed with cockleshells, known as ‘cultch,’ covering 2,500 metres square onto the seabed.

In a few weeks, 30,000 oysters sourced from south Wales will be transferred to the site to seed the area at the Swanwick bend in the River Hamble in a few weeks, after passing through a strict biosecurity process where they are cleaned, measured and checked.

The Solent was once the largest and most important oyster fishery in Europe, but over the last decade oysters have significantly dwindled in numbers as a result of poor water quality, competition from invasive species, disease and fishing pressure.  The loss of the native European oyster removes the many ecosystem services that a healthy oyster population provides.  Adult oysters can filter as much as 200 litres of seawater each day, improving water clarity and removing excess nutrients.  Oysters also stabilise marine sediments and dramatically increase biodiversity, including commercially important fish species.

Scientists from Blue Marine, University of Portsmouth and University of Southampton will measure oyster survivorship and biodiversity gains and compare them to another part of the river where no restoration activity is to take place.

Louise MacCallum, Solent Project Manager for Blue Marine said:

“This will be our second restored oyster reef in the Solent, the first having been built in Langstone Harbour at the end of 2021.  The Langstone reef has already attracted a wealth of marine fauna including cuttlefish, catsharks and even seahorses.  It is exciting to see what kinds of marine creatures our new reef will attract in the River Hamble.”

Joanne Preston, Reader in Marine Ecology and Evolution at the University of Portsmouth said:

“We hope this reef creates a tipping point; kick-starting a population of native oysters that builds over several generations and provides offspring that will spill over and populate other areas.”

The Endangered Landscapes Project has funded the five-year partnership.

Photo: Blue Marine Foundation