Defining a Unit of Assessment (UoA)

In an MSC assessment, a Unit of Assessment (UoA) is defined by the target stock, fishing method, vessel type or gear and fishing fleet.

The MSC defines the target stock as the species and stock that will be certified against Principle 1 and which may subsequently enter the supply chain as MSC certified, and ultimately carry the MSC logo. The sustainability of all fishing on the target stock must be assessed under Principle 1 (i.e. the impact of the assessed fishery and all other fisheries and additional mortality). All other species caught within the UoA must be assessed against the MSC Principle 2.

Currently, fisheries seeking certification may define their UoA in any way so long as it is specific and in line with these requirements. This allows for parts of a fishery to enter certification, rather than requiring all fishers on a single stock to be certified at once.

This has resulted in situations where a particular fleet may, within a single trip, fish for the same target species on both certified and non-certified units of certification. If there is a risk of mixing of certified and uncertified fish, the MSC requires that segregation and traceability is maintained such that a fish eligible to carry the MSC logo is capable of being traced back to the certified stock.

Where this cannot be easily assured from the practices on board a vessel, the MSC requires that the Conformity Assessment Body (CAB) consider whether the at-sea activity of the fishery should be subject to MSC Chain of Custody (CoC) certification.

In early 2017, the MSC initiated a review of its UoA requirements in response to concerns that the current rule allows a vessel to catch fish from the same stock using both certified and uncertified fishing gear or catch methods on a single trip.