Whitebait on the decline

Q. Whitebait season came to a close last week, with several regions reporting poor catches. Is the fishing practice sustainable? A. Unitec environment and animal sciences senior lecturer Stephane Boyer says no, it’s not: I don’t believe that whitebait fishing practices in New Zealand are sustainable.

One of the big issues is that we don’t know what species we catch.

Whitebait is composed of five different species of fish but, as babies, they all look very similar.

Among these five species, three are declining and one is recognised as a threatened species.

Yet we fish, sell and eat them all without distinction. It’s also been shown that poor water quality and the disappearance of their breeding habitat affects whitebait populations.

What the industry lacks is a dedicated stock-monitoring tool for whitebait.

But what is certain is that we are not getting any less effective at catching whitebait.

So a drop in the total catch in any season can reasonably be imputed to a drop in the population of juveniles.

I am leading a research project on the DNA identification of whitebait (with funding from the Royal Society of New Zealand). This tool could eventually be used to differentiate whitebait catch containing endangered species from those only including species of least conservation concern.

Eventually, it could also be used to map the distribution of the different species in rivers and to protect areas that are important for the endangered and declining species.

- Commentary gathered by Science Media Centre NZ

JOHN HAWKINS/FAIRFAX NZ A fisherman checking his whitebait net on the banks of the Waihopai River.

Whitebait, the Kiwi fritter favourite, is suffering declining numbers.