Concern as Canty smelt crisis mirrored across globe

Anglers fear a tiny, cucumberscented fish could be teetering on the verge of extinction after a survey of its American counterpart yielded disastrous results.

Stokell’s smelt is native to the east coast of the South Island – usually found from North Canterbury’s Waiau River to the Waitaki River – and is officially classified as ‘‘at risk’’.

New Zealand Federation of Freshwater Anglers president Peter Trolove, who is a fish vet, said recreational fishers had noticed a drastic decline in the once-common species.

He was particularly concerned after learning the California Department of Fish and Wildlife was unable to find any of the fish’s northern hemisphere cousins – the delta smelt – during its 2020 Fall Midwater Trawl Survey.

‘‘[The] delta smelt is an indicator species that reveals the overall health of the San Francisco Bay-Delta Estuary.

‘‘Once the most abundant fish in the entire estuary, numbering in the millions, it is on the verge of extinction in the wild.’’

Trolove said Stokell’s smelt was in a similar endangered position.

‘‘The species is an important element in the food chain web that involves native seabirds, native fish and sea-run trout ... if the Stokell’s smelt go extinct, the species that feed on the smelt have the potential to go extinct as well.

‘‘It’s like a red light – you have to stop or there will be a crash.’’

The fish only live up to two years, so Trolove said a single failed breeding season could spell disaster.

He felt the Department of Conservation (DOC) was not taking anglers’ observations about the low number of smelt seriously enough, and said the results were already starting to show.

Earlier this month, Rangitata Huts residents reported large numbers of dead endangered black-billed gull chicks by the river, sparking fears there was a lack of food, including smelt.

Trolove said they were concerned low water levels in Canterbury’s braided rivers, caused by the water take for irrigation, was behind the population drop.

‘‘It would be most accurate to state that the trends in the abundance of Stokell’s is not presently known . . . although anecdotal angler reports from locals show alarm and despair at the dramatic decline . . .’’

In November, Environment Canterbury (ECan), DOC, iwi and Fish & Game teamed up to survey fish species in the Rangitata, Ashburton and Rakaia rivers.

ECan science director Tim Davie said they caught smelt in all three, but were still waiting on gene testing results to confirm whether they were common smelt, or Stokell’s smelt.

He said their findings would be finalised in the next few weeks, and they would then be able to see whether numbers had dropped since the 1980s.

Researchers will return to the sampling sites about the same time this year for another survey.