American eel (Anguilla rostrata) recruitment has declined dramatically, in parallel with that of European eel (Anguilla anguilla). Since both species spawn in the Sargasso Sea and migrate as larvae to continental waters, the coincidence in recruitment failure implies an Atlantic‐wide cause, due perhaps to ocean climate. There is indirect evidence that the Gulf Stream has weakened in the 1980s. A slower Gulf Stream could interfere with larval transport and generate observed patterns of declining abundance of American eel only in northern North America and relatively uniform declines of European eel throughout Europe. While specific causes are still unclear, these data indicate a threat to both species and to their commercial fisheries.

No abstract

Measurements taken from a series of photographs of otoliths of 37 eels caught in a stretch of river of 150 m length were used to prepare a growth curve based on back-calculated measurements. Values of L , = 1045 and K = 0.046 were determined. Mean incremental growth calculated as 33 mm per year agreed closely with increments determined from growth observed up to 4 years after tagging eels from the same location. Inconsistencies in results of age determinations based on burned otoliths are described but it is concluded that the technique yields results of sufficient reliability to be used in practical management situations.

No abstract

The eel migrations in Burrishoole, Ireland, have been studied from 1959 to 1988. Numbers of eels in the catches have decreased. The mean length of male eels has increased by 16.5 yo and females by 27.6 yo. Total weight of catch has not been affected by the drop in numbers. A change in sex ratio from 94.5 yo males in 1962 to 37.5 yo in 1988 has also occurred. A decrease in elver recruitment into freshwater and a change in the environmental status of the system are discussed as being possible reasons for these changes.