The inshore King Scallop fishery of the Saint-Brieuc Bay is probably represented by the highest density levels in European scale. For the period 1962-2018, landings usually oscillated in a range of 4000-6000 t with some extreme values as 12500 t (season 1972/73) and 1300 t (season 1989/90). In recent years, the exploitation has been undertaken by 220-230 vessels (99% dredgers, 1% divers) whereas the maximum numbers of vessels was reached in the mid-70's (466). Many historical stages throughout more than a half century of exploitation (from the early 60's onwards) show the vanguard position of this stock for the scallop French fisheries.

The adult biomass includes all age groups 2 and +, it provides an index of the potential fecundity of the stock. The exploitable biomass corresponds to individuals larger than 102 mm (MLS in VIIe French waters), thus it is a fraction of the adult one. Those indices show cyclical pattern with a downwards trend in the period 2006-2013 (respectively -53% and -57% for adult and exploitable biomass). Afterward, an increasing phase is obvious. In 2018, the historically highest level (respectively +59% et +35% for adult and exploitable biomass compared to 2017) is reached. Comparing year 2019 vs. maximum level for 2000's (year 2006) gives +6% for the adult biomass, although -6% for the exploitable one estimated in September 2019  but +5% for the same index in the middle of the current fishing season (2019/20) under assumption for average level of individual growth parameters for King scallops: many indicators provided owing to the biological sampling at auction during the first half of the current season suggest that the actual individual growth performances should be higher than the average expected ones.

The required annual survey COSB aims to four main goals:

1. Observation of fluctuation of natural resources and implication in terms of management.
2. Bio-economic analysis and scenarios of exploitation.
3. Relationships King scallop and Americal slipper limpet.
4. Relationships recruitment/environment.