What do catches and surveys tell us?

Are changes in the observations telling us that fish abundance has changed, or that the fish are being encountered differently?

An abundance index is a series used to track changes in the quantity of fish. Interpreting one requires understanding where, when and how the observations were collected.

What the papers show

The submitted papers examine catches, fishery catch rates, acoustic surveys and biological sampling. Some abundance signals differ. One paper reports an increasing standardised index in 2026, while another describes a marked early-year decline. These author-reported results call for a comparison on a consistent basis before drawing stock-status conclusions. Sources: JM10, JM15.

Why it matters for management

A catch rate can change because abundance changes, but also because fishing location, fleet behaviour, technology or fish availability changes. Acoustic surveys provide another view, with their own coverage and interpretation issues. Reliable advice depends on understanding these differences before choosing the information used in the assessment.

What has been agreed?

The annotated agenda asks SC14 to review suitable assessment inputs and their uncertainties. The current sources describe the inputs proposed for review; the agreed meeting record is needed to establish the Committee’s choices. Source: Doc02, item 5b.

What needs resolving?

Compare the same periods, fleets and areas before interpreting different trends. One of the submitted catch-rate series ends in the first half of 2025, so it cannot be treated as a 2026 update. Explanations involving the environment or availability of fish remain hypotheses where unresolved. Sources: JM15, JM19.