Size of maturity of the common whelk, Buccinum undatum: Is the minimum landing size in England too low?

Abstract

The common whelk Buccinum undatum is widely distributed around the coast of the United Kingdom, and supports valuable fisheries in many areas around the English coast. A minimum landing size (MLS) of 45mm currently applies in England and is generally viewed as a useful management measure to help support a sustainable whelk fishery. However, there is limited knowledge about regional variation in the size of sexual maturity (SOM) in English whelk populations. Whelks were collected at 12 different sites around the English coast and SOM estimates were compared to the current MLS. The national SOM was above MLS, and the proportion of mature whelks at the MLS was extremely low or zero at most sites. Significant differences were found in SOM between sites and between sexes within some sites. The current MLS may therefore provide little or no protection to the English spawning stock, and whelk populations may thus be vulnerable to recruitment overfishing. Site-specific values of SOM suggest that discrete populations may occur at each sampled location, despite some being geographically close to one another. We recommend that regional rather than national management measures are necessary to protect English whelk fisheries, and further research is needed to determine the appropriate MLS for each region.