Discard issue key to any review of Common Fisheries Policy

The discard problem becomes acute when individual quota allocations are mismatched between these species, for example when the quota for cod is exhausted but the quotas for haddock and whiting remain unused.

Published scientific work has shown that beam and otter trawlers in the Celtic Sea area (south and west of Ireland) have respectively discarded 71 per cent and 64 per cent of their catch by numbers, and 42 per cent and 36 per cent by weight.

It is important to note that discards may have beneficial effects for other animals. Various scientific studies have shown that discards have become an important food source for populations of some seabird species and also for bottom-living scavengers.

There are many interrelated factors that cause discarding. The main reasons are linked to economic/market considerations or to comply with regulations. Lack of marketing opportunities, quality considerations or large price differentials between or within fish species can all induce discarding. The main drivers and their contribution varies considerably in different fisheries, but fisheries that are managed extensively by landings control regulations are often characterised by high discard rates.

(It is important to note that in Europe although annual fishing opportunities are derived from total allowance catches, in fact it is total landings, not catch, that are controlled.)

The stock status can be a big factor in discarding. For example, the haddock stocks are prone to very successful spawning and, in years where juvenile haddock are abundant, significant discarding of small fish may occur.

EU regulations that set limits to the catch composition on board a vessel may compel fishers to discard excess catches of specific species. Fishers are aware that this type of “regulatory discarding” of marketable dead fish serves no conservation purpose.

This undermines their faith in the management system and can lead to non-compliance with the regulations, as happened in Kilmore Quay this week.

Inappropriate fishing gear is also a major problem in some fisheries. For example, many beam trawl fisheries target sole with 80mm mesh which is compatible with the minimum landing size for sole but also results in high catches of small plaice for which there is no market. Discard rates for plaice are very high as a consequence.

Internationally, it is well-recognised that managing discards is complex. Each sea area has a different mix of fish species and a different mix of adult and juvenile fish. Therefore, they are likely to require a specific suite of measures to minimise discards.

For example, in overexploited fisheries, reducing the amount of days that vessels can fish (effort reduction) is likely to be one approach to decreasing discards. Effort reduction may not be necessary if “discard reduction devices” take a central role, for example introducing devices into the trawl that allow small fish escape.