The precautionary approach and the management of the European eel (Anguilla anguilla) – critical remarks

Recruitment and commercial catches of European eel have been in decline since the late 1970s. So far, the reasons are not well understood. A range of potential natural and anthropogenic reasons have been discussed, but the relative importance of the factors is unknown. As a consequence of the decline in recruitment an urgent need for protective management measures was concluded. The main approach is to restrict the fishery on eel, in particular with reference to the precautionary approach. However, in view of the lack of knowledge on the factors responsible for the recruitment decline and by considering that many yellow and silver eel stocks in freshwaters depend on restocking by the fishery, such simplified conclusions are critically discussed. A concept for the sustainable management of eel has to include 1) research on the factors determining the population dynamics, in particular during the oceanic stages, 2) a stronger consideration of socio-economic aspects, and 3) intensified research on artificial reproduction and rearing of eel.

Recovery of the stocks of the European eel (Anguilla anguilla) by spawner enhancement

The production of healthy high quality female European eel in recycle systems is proposed as a means to secure sufficient numbers of silver eel for spawning migration in order to meet the requirements of the European Commission’s proposal for a Regulation for the recovery of the stock of the European eel. Main advantages besides checks for parasites and viral diseases and avoidance of elevated levels of specific pollutants are the easily controllable numbers of spawners to be released and a reduction of labour and costs that will occur when acting along the lines of the Commission’s proposal.

The family of chironomids or midges - Chironomidae. Keys to larvae and pupae [Translation from: Guide to the freshwater invertebrates of the European area of the USSR (Plankton and benthos) (ed. L. A. Kutikova and Ya. I. Starobogatov), p.371-431. Leningrad, Gidrometeoizdat, 1977]

The translation of this section of the larger publication ”Opredelitel' presnovodnykh bespozvonochnykh evropeiskoi chasti SSSR. (Plankton i bentos)” provides identification keys to the larvae and pupae of chironomids that occur in the Soviet Union. The morphology of the larvae of Chironomidae is described in the introductory part.

Review of investigation on the feeding of the European grayling [Translation from: Flora Slodkowodna Polski. Tom 2. Cyanophyta, Glaucophyta (ed. K. Starmach) p350-352. Warsaw, Polska Academia Nauk, 1966]

The composition of the food of the European grayling and the character of its feeding has been studied fully enough, but this knowledge is scattered in the literature and often contradictory. rare exceptions, analysis of the results of different investigations. Therefore the proposed short outline of the history of the study of the problem with a description of the basic data on the feeding of the grayling in different geographical areas is presented as expedient and opportune, primarily in relation to the determination of immediate problems and the trend of research.

The ecology and management of the European grayling Thymallus thymallus (Linnaeus). Interim report

The European grayling, Thymallus thymallus, is a highly under-rated freshwater fish, particularly in the United Kingdom. As such, little scientific research has been conducted on its biology, ecology or specific management plans, in comparison to the related species, salmon, Salmo salar L. and brown trout, Salm.o trutta trutta L. or the nearest relative to T. thymallus, the Arctic grayling, Thymallus arcticus (Walbaum), whose life history has been well documented in view of its high ranking by anglers, as a game fish. However, the importance of sound scientific research cannot be over stressed for this species, which can potentially provide an excellent fishery and source of income in salmonid depauparate rivers. The aim of this report therefore, is to review all available information on the biology, ecology and management of the European grayling, T. thymallus, incorporating findings for T. arcticus to bridge subjects where the literature is scarce, and propose management strategies for T. thymallus in the United Kingdom, bridge subjects where the literature is scarce, and propose management strategies for T. thymallus in the UK.

Bycatch of billfishes by the European tuna purse-seine fishery in the Atlantic Ocean

Billfishes are a component of offshore ecosystems; thus it is important to quantify the impact of the tuna fishery on these species in the world’s ocean. The aim of this study was to assess the bycatch of billfishes generated by the tropical tuna purse-seine fishery in the eastern Atlantic Ocean. Information on bycatch was collected by observers at sea during the European Union Bigeye Program. With a total of 62 observers’ trips, conducted on Spanish and French vessels between June 1997 and May 1999, this project is the biggest observer program ever carried out in the European tuna purse-seine fishery. This study showed that billfish bycatch by the purse seiners is very low (less than 0.021% of the total tuna catches and less than 10% of the total billfish catches currently reported). A Monte Carlo simulation was performed to account for some uncertainties in the fishing strategies of purse seiners operating in this ocean. One of the findings of this study indicated that the temporary moratorium on fishing with FADs (fish aggregating devices), adopted by the European purse-seine fishery in the eastern Atlantic Ocean, produced a decrease in incidental catches of marlins from 600–700 metric tons (t) to less than 300 t. In contrast, this trend was reversed for sailfishes, for which the bycatch increased from 25 t to 45 t. The difficulty of defining indices that express the conservation status in marine fishes and that gauge key ecosystem parameters and the need to promote an ecosystem approach for large-pelagic-resource management which takes into account biologic and socioeconomic criteria are briefly discussed.