Original publication: May 2016
Authors: Clara Ulrich, Lars O. Mortensen, Alexander Kempf, Prellezo Raúl, Santurtún Marina, Andonegi Eider, Louzao Maite, Garcia Dorleta, Iriondo Ane, Sarah B. M. KRAAK, Christian VON DORRIEN, Uwe KRUMME, Lena VON NORDHEIM, Rainer OEBERST, Harry V. STREHLOW and Christopher ZIMMERMANN
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Introduction

The three reports, on the North Sea, the Baltic Sea, and the Atlantic Ocean (Bay of Biscay), have commonalities as well as differences, both in terms of the topics covered and in terms of the findings and conclusions. In this document we will highlight these differences and commonalities.

 

First of all, the North Sea report provides helpful background information on the concept of MSY, its history, novel extensions of the MSY concept (e.g. MMSY) and their problems. Likewise, the Baltic Sea report provides a general section on implementation error and on how the behavioural sciences may be of help to reduce this. This general information is applicable to all three reports.

The reports on the North Sea and the Bay of Biscay, but not the report on the Baltic Sea, include extensive discussion of modelling studies and results. The authors of the Baltic Sea report had agreed with the client on forehand that they would not include such modelling studies; their arguments for this decision are at the bottom of page 12 of their report.

The reports on the North Sea and the Bay of Biscay, but not the report on the Baltic Sea, provide extensive discussion of mixed-fisheries and choke-species aspects (and related concepts of pretty good yield (PGY) and F-MSY ranges). The authors of the Baltic Sea report did not include these aspects because a report devoted to these matters, commissioned by the European Parliament, was already prepared in the summer of 2015.

The report on the Baltic Sea, but not the reports on the North Sea and the Bay of Biscay, includes sections on recreational fisheries and other anthropogenic factors. In the case of the Bay of Biscay, although, as mentioned in the report, the impact of recreational fishery is increasing for some particular stocks, it still cannot be considered as a major factor on the ecosystem future evolution. In the North Sea, recreational fisheries and other anthropogenic factors are likely important mainly for the English Channel and coastal areas rather than the main North Sea.

It can also be noted that there is considerable scientific activity related to the Marine Strategy Framework Directive and Good Environmental Status, so information on the topic of anthropogenic factors is available elsewhere. Furthermore this was not an explicit  request in the given TORs.

Most of the statements in the North Sea report on biological interactions are also valid for the Baltic Sea. Nevertheless, it should be noted that the food web is much simpler in the Baltic Sea compared to the North Sea.

On the topic of the impact of reduced discards, the statement that the main threat is from increased predation by scavenger seabirds on other seabird species (in the North Sea report) is probably not transferable to the Baltic Sea, because the main scavenging seabirds in the Baltic are herring gulls, which also feed on dumping sites and are not as big as greater blackbacked gulls or skuas in the North sea. It should also be noted that the amount of discards falling under LO is much lower in the Baltic compared with the situation in North Sea.

Conclusion

All three groups of authors, of the North Sea, Baltic Sea, and Bay of Biscay reports, agree that the landings obligation (LO) and catch quotas should provide incentives for change in the fisheries, including adaptation through taking up selective gears and spatiotemporal effort reallocation, but also quota redistribution within and between member states (swapping). However, these incentives will only manifests if the LO and catch quotas are fully enforced. If they are not fully enforced, there will be an incentive to continue discarding. Because it is not known to what extent the LO and catch quotas will be enforced it is not known whether the
incentives for change will manifest, and therefore the future behaviour of the fisheries cannot be predicted. However, bio-economic models need an assumption on future fishery behaviour. Without any evidence of change, the most obvious choice for such an assumption so far is the assumption of no change in fishing patterns. Therefore, many models were based on the assumption that catchability in the future would be the same as in the recent past. This assumption has led to the situation that if one species chokes the fishery the fishing opportunities for other species are underutilised. Whether this will in actual fact happen is not known. Two other possible outcomes could be the continuation of over quota discarding, or adaptive change in fishing patterns leading to a better balance between quotas and catches. However, predictions of these outcomes cannot be quantified because no justifiable assumption on fisher behaviour can be made.

The Baltic Sea report contains a chapter on important aspects regarding governance and drivers of (non-) compliance. This part is largely generic and the considerations given can apply to most fisheries.

[…]

Link to the full study: http://bit.ly/573-440

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