International eel symposium, 2003 - Quebec August 11, 2003
Oral Presentation

The Status of Freshwater Eels in New Zealand

Jellyman, D.* National Institute of Water & Atmospheric Research Ltd., P. O. Box 8602, Christchurch, New Zealand

Presenter email address: d.jellyman AT niwa.co.nz

Abstract Text: New Zealand has two species of freshwater eel that are subject to extensive commercial and customary fishing- the endemic longfin (Anguilla dieffenbachii), and the Australasian shortfin (A. australis). The shortfin, a lowland species, has been impacted by loss of habitat through wetland drainage and river channelisation. The longfin is more widely distributed, but upstream access has often been compromised by installation of dams. Typically, both species are slow-growing, and at spawning escapement, females are often in excess of 30 and 50 years old for shortfins and longfins respectively. This longevity means that both species are vulnerable to overfishing. While present indications are that the shortfin fishery is being maintained, there are concerns about the well-being of longfins arising from several studies:
1. Evidence of low recruitment in small streams;
2. Evidence of a marked reduction in size of eels in fished catchments;
3. Reduction in catch per unit effort in some regions;
4. Evidence that upper size limits (4 kg) are ineffectual;
5. A marked reduction in the proportion of females in some catchments.
Collectively, these features give concern about the ability of longfins to withstand present levels of exploitation.