Declines in recruitment of temperate anguillid eels have occurred in the past 30 years in many areas of their species ranges. The cumulative effects of anthropogenic changes to their freshwater growth habitats are likely contributors to reductions inpopulation sizes, but changes in ocean-atmospheric conditions in the ocean also appear to be contributing to the declines. This papet reviews how changes in the ocean may contribute to tecruitment declines by affecting the spawning location of silver eels, larval feeding success, or the transport of their leptocephalus larvae by ocean currents. Recruitment of European eels Anguilla anguillla has shown correlations with the North Atlantic Oscillation and specific changes in ocean conditions in the Sargasso Sea where spawning and development occurs. The American eel A. rostrata spawns in an area that overlaps with the European eel and so could also be affected by these types of changes. Recruitment of Japanese eels A. japonica appears to be correlated tothe El Nino Southern Oscillation index and latitudinal changes in salinity fronts in the western North Pacific. The general spawning and recruitment patterns of the temperate Australasian shortfin eels A. australis and New Zealand longfin eels A dieffenbachii in the western South Pacific are similar to those of the northern temperate anguillids and also may be affected by El Nino-related factots. The changes in ocean conditions associated with atmospheric forcing or a warming of the ocean could alter the biological characteristics of the surface layer where leptocephali feed, due to changes in productivity or community structure, in addition to having possible effects on larval transport and location of the spawning areas by silver eels. Changes in ocean-atmospheric conditions could result in lower feeding success and survival of leptocephali, or increased retention in offshore areas due to changes in the location of spawning areas, resulting in reductions in recruitment.
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