VARIABILITY IN GROWTH-RATES OF FRESH-WATER EELS (ANGUILLA, SPP) IN NEW-ZEALAND

Both species of New Zealand freshwater eels (the shortfinned eel Angui lla australis and the longfinned eel A. dieffenbachii) are widespread and abundant, supporting Important commercial and recreational fisheri es. This article reviews growth studies from 35 widely distributed sit es throughout New Zealand and discusses factors that influence growth rates. Length at given age is characterized by high intra- and inter-p opulation variability; growth rates for eels >30 cm are typically slow (2-3 cm per gear) and linear, with females generally growing faster t han males. Water temperature affects the length of the growing season, although growth rates are not correlated with latitude. Other factors suggested as affecting growth rates are eel density, quantity and qua lity of food, and interactions between both eel species. Although grow th of some New Zealand eel populations is the slowest recorded for any species of Anguilla, growth in culture can be rapid, similar to that of other temperate eel species.