Willem Dekker, Brian Knights and Christopher Moriarty
At the Eighth Session of the EIFAC Working Party on Eel, Olsztyn, Poland, 24–29 May 1993, an impressive weight of evidence was presented on recruitment failure of the European eel. First noted by the Working Party in the early 1980s, a low level of capture of glass eel and of inward migration of elvers had persisted. Such prolonged failure was considered likely to have serious consequences for the fisheries for eel at all life stages and in all regions of its habitat throughout Europe. Moreover, the possible endangerment of the species itself was discussed. However, in this context it was decided, that - in contrast to the situation in the American eel in which the only data available point to a continuing decline - there was not enough hard evidence to conclude that the European eel is at present an endangered species.
Concern in 1993 arises from the fact that the recruitment failure has now lasted for a time period equivalent to the average life span of a mature eel in the northern part of its range. This implies that the drop in stock levels caused by recruitment failure might generate an increased downward trend in future recruitment because of the diminishing numbers of mature eels returning to the spawning places.
It was clearly understood that enhancement of the fisheries together with conservation of the species could be seen as a conflict of interests. However, noting that the primary concern of EIFAC is the management of fisheries, the Working Party decided to concentrate on proposals likely to have a positive effect on the status of the stocks. With appropriate management, this would lead to enhancement of spawning escapement throughout the entire habitat of the European eel.
In the past, the responsibility for the management of eel fisheries has been de facto at the national level in the absence of proven stock-wide problems over the entire range of the species. The subsidiarity principle has been observed. Although the recruitment failure had occurred at all monitoring stations, there was not - even at the end of the 1980s - enough evidence of stock-wide decline which was likely to continue to justify consideration of stock wide management.
The situation in 1993 must be seen as a watershed because it marks the persistence of recruitment failure throughout a period equal to the average life cycle of a northern European eel - and therefore over more than one life cycle of eels in southern Europe. The Working Party therefore decided that the time had come to reconsider the needs and opportunities for stock wide management actions.
It is of the greatest importance to note that, while this discussion on the future of eel fisheries was stimulated by grave concern for the very existence of the fisheries and the welfare of the fishermen, the prospects for enhancement of stocks and development of the fishery throughout Europe are excellent. The management actions required, however, must be taken on an international scale since the eel is unique in European inland fisheries in depending on a single breeding stock in a region outside the jurisdiction of European nations.
Research results stimulated by and reported to the Working Party on Eel confirm that major steps in management leading to enhanced fisheries have yet to be taken on a Europe-wide basis.
The Working Party has identified the following measures as being of proven efficacy and capable of being implemented without delay:
Purchase of glass eels for distribution to regions known to be deficient in stocks of growing eel.
Facilitation of natural ascent of elvers to under-utilised habitats, including former habitats which have been rendered inaccessible by the construction of dams and other obstacles.
Implementation of measures to prevent the destruction of silver eels in hydro dams and pumping stations in order to preserve the eels both for exploitation and for breeding escapement.
The adoption of such measures should in all cases be accompanied by a major scientific monitoring programme, as outlined in Annex F, so that their efficacy may be fully quantified in the interests firstly of ensuring that the best possible use is made of a finite resource and secondly in the expectation that improvements may be made in the techniques employed.
The scientific programme will include:
The compilation of a status report on the eel.
Planning and execution of internationally co-operative research on the causes of the decline in recruitment with a view to discovering the means of redressing the current situation.
The investigation of suspected cases of over-fishing and formulation of measures to ensure that the fishermen obtain greater benefits through more rational exploitation.
Determination of the effects of contamination, parasites and diseases on eel stocks and breeding prospects.
Enhanced monitoring of recruitment at all stages, including oceanic breeding and migration.
Investigation of the efficacy of steps taken to enhance stocks with a view to maximising the cost/benefit of all artificial inputs.
