Cockles and mussels, Alive, Alive-O

Living next to the Solent with a beach and foreshore recognised as of Special Scientific Interest is a positive aspect of life in Hill Head and Stubbington. But our Solent has a few problems and is in need of our care and attention, writes Bob Seymour. Allowing the many birds that feed at low tide a little bit more relief from our pet dogs scaring them when off a lead is one way.

It is the level of Nitrates in the Solent’s water though that needs our urgent attention. Fertilisers on Hampshire fields and domestic waste from the houses that fringe its shores have accumulated in the Solent causing a big rise in oxygen depleting algae growth. All life in the Solent suffers, and the water pollution makes it a more hazardous place to swim and sail.

Some actions have been taken, encouraging less reliance on nitrate fertilisers, a temporary stop to any large housing developments. Another might be to take better care of the shellfish that live here.

The Solent shellfish are known as bivalves – Cockles Clams and Oysters. They are nature’s filter feeders, their simple life cleans up after our polluting lifestyle. As a result they also become dangerous to our health if eaten!

Scientific studies recognise these little creatures as ‘keystone species’, performing the task of ‘ecosytem engineers’. Their filter feeding behaviour removes particles, both organic and inorganic from Solent’s water transferring the matter to the seabed to either be locked into the sediment or be food for even smaller organisms in the ecosystem. They are especially adept at removing bacteria such as e-Coli, which we are so good at putting into the water from our sewage treatment process.

Undisturbed, these little saviours cluster in large colonies where the impact of their cleaning process is really important for us. In fact they perform three key tasks for us – filtering the water, trapping carbon and they can help reduce shoreline erosion.

Across the Solent over-harvesting of shellfish has had many negative impacts. There are already several controls managed by the Southern Inshore Fisheries and Conservation Authority – a limit on both the size of shellfish that can be taken, a seasonal halt on taking cockles between February and May, for Oysters between March and November.

Picture from Southern IFCA

In 2018 a total ban on fishing was temporarily introduced as the full impact of over-fishing was identified. The Hill Head fishery, covering the foreshore and halfway across to the Isle of Wight has been declassified as a fishery because of the poor quality of the water.

In 2020 a leak from the Hook sewage treatment outfall resulted in a temporary total ban by Fareham’s food hygiene service on the taking of shellfish. On the positive side there are several initiatives to reintroduce Oysters into the Solent, an attempt to both improve their ability to clean our water and to revive a small fishing industry that has been around for several thousand years.

If we could just leave the shellfish alone in the sea and under the sands at low tide for a much longer period, perhaps a few years, their work would be even more effective for us.

We can play a small part here by encouraging a wider appreciation of the value of a shellfish in the water rather than in a stew. At the very least we can properly enforce existing controls to stop the large scale gathering of them on our shore by illegal gangs as we saw on one occasion last year. Again, you can play a role by letting the authority know if you see any sign of large scale gathering at low tides; report such harmful activity to Fareham’s food hygiene service on 01329 236100.

Let us know what you think of this local environmental issue.