No. 74: Mar-Apr 1991
Garter snakes are reknowned for their habit of congregating in large, writhing masses, but we never heard of "eel balls" until A. Gardiner mentioned them in a recent issue of the Fortean Times.
"These [eel balls] are recorded in Christopher Moriarty's excellent Eels: a Natural and Unnatural History (David and Charles, 1978). Moriarity cites Pliny as the earliest historical reference. According to him, Eel Balls occur in Lake Garda, Italy, when it has been storm-tossed by the effects of the October 'Autumn star'. Smitt in his Scandanavian Fishes (1895) says that eels knot themselves together in bunches 'up to a fathom in circumference' and are seen rolling along the stream beds, or, strangely, resting in this position. On 17 August 1935, fishery scientist J.C. Medcof observed, in the outflow of Lake Ainslie in Nova Scotia, 'three splendid clumps of Eels, half a metre in diameter, 30 to a clump, knotted tightly and remaining motionless in the rushes.' Medcof mentions that Eel Balls are sometimes free floating on the surface, which suggests formation with an air pocket or some communal control of air bladders. He says that this behavior occurs before eels 'silver' prior to the spawning migration. The record of Eel Balls in Nova Scotia proves that this behaviour is not confined to the European Eel."
(Gardiner, Alan; "Eel Oddities," Fortean Times, no. 56, p. 53, Winter 1990.)