Whelks and Mussels......

.....form an important part of the local economy, as Lauren Parkhouse of the Devon and Severn IFCA told Coastwise members - see the talk on the YouTube link below.

The Inland Fisheries Conservation Authority is part of an overall marine and inland waters management process starting at DEFRA, through the Marine Managment Organisation, with the Environment Agency, Natural England and the IFCAs carrying out their own functions.

The whelk fisheries have suffered a decline in populations, so extensive work was done on size and age at sexual maturity, particularly the SOM (Size of Maturity at which over 50% are sexually mature), and the seasonality of breeding. The results showed that the minimum size allowance of catches is far too small to allow effective breeding, and that ideally it should be increased from 45mm to over 75mm, with some variations dependant upon location on the N or S coast.

In addition the peak breeding season is in the last 3 months of the year, when the value of catches is highest.

However, it was judged that the effect on the idustry would be too severe if big changes to minimum take size, and close seasons were introduced immediately, so a progressive approach to changes through Fisheries Research and Management Plans has been adopted.

For mussels, the position is slightly different. There was a big decline in 2021/3, but a gradual recovery since, after catch limits were imposed.

Significant research based on intertidal and subtidal surveys has been undertaken to establish stock levels. Above low tide level, a 'Dutch Stick' is used to sample mud and mussel content, then calculations on area coverage, density and tonnage, taking account of bird feeding, are made. The subtidal equivalents are undertakne by sidescan sonar scanning and interpretation, backed up by grab samples to prove the results.

Overall, there's a cautiously optimistic picture emerging, and it's good to see that the IFCA is adopting a strongly scientific approach to its work, leading to carefully-judged protection measures, based on the local economic conditions.

You can watch the whole talk here......


Copyright Coastwise