More than 105,000 tonnes of exploitable biomass in the Bay of Seine, 63,000 tonnes in the Bay of Saint-Brieuc says Ifremer fisheries scientists
According to the latest Ifremer scientific assessments carried out this summer, scallop populations in the Bay of Seine and the Bay of Saint-Brieuc have once again beaten previous abundance records, confirming the favourable trend of recent years.
All the indicators of good condition for the scallop population in these two areas are green for the fishing season which officially starts this month, October.
In the area from Barfleur (50) to Cap d’Antifer (76), the situation in 2022 in the Seine Bay deposit continues to be exceptional. The total exploitable biomass over the entire season is estimated at more than 105,000 t (including 85,000 t in the Bay of Seine alone, sensu stricto). The arrival of a new generation of juveniles is again very good. And the presence of a record remainder of shells 3 years old and over, after a full year of operation, confirms the good health of the population.
Only downside: the shells are smaller due to stunted growth. At the start of the season, the entire population will not yet have reached the minimum regulatory size of 110 mm to be marketed. It can be estimated that only 61% (i.e. 64,425 tonnes) will be immediately exploitable. The rest of the biomass will gradually reach this minimum size during the season. The production of phytoplankton on which the shells feed seems to have been lower this summer, due to the lack of fresh water supply and the particularly strong heat. This finding, which is identical in the bay of Saint-Brieuc, could be one of the reasons for the growth retardation observed at the two sites.
In the bay of Saint-Brieuc, the total immediately exploitable biomass (of 102 mm or more) announced today is 46,000 t, i.e., 5% more compared to the already exceptional year 2021.
But it could reach 63,100 t at the end of the year (middle of the fishing season) depending on the growth of the shells throughout the season (which would represent an increase of +13% compared to last year). The total biomass of all ages combined exceeds 87,700 t this year, an increase of 19% compared to 2021, which was nevertheless the record year for 61 years. The spawning stock biomass increased by more than 16% compared to last year.
These figures confirm for the moment the favourable trend observed since the beginning of the 2010s, in connection with the management put in place by French fisheries. We can cite in particular the overall reduction in the fishing effort by setting up fishing dates and times, the improvement in the selectivity of gear with the use of larger dredge rings, or even the establishment in the bay of the Seine of a fallow zone which changes each year.