Fish Are Fast Learners

Fish Are Fast Learners

(16 July 2000)

New Zealand’s brown trout are becoming smarter and more difficult to catch, say researchers.

John Hayes and Roger Young at the Cawthron Institute, are looking at the effects of increasing numbers of anglers and how this affects the sustainability of our brown trout river fisheries.

“Anglers release most of the fish they catch in backcountry rivers. These fish often hide for several days and are not available to other anglers. They also appear to learn and become choosier over the artificial flies they will take,” say the researchers.

“In really remote rivers, where trout are naive, just a few anglers can catch a large proportion of the trout population. This could threaten the viability of trout stocks if catch-and-release is not practiced. The wariness of trout in more heavily fished rivers probably protects them to some extent.

“For expert anglers, a decrease in catchability of trout may increase the challenge and sense of achievement when one finally succeeds. However, a newcomer or less-skilful angler may give up the sport if they never catch a fish.”

The research is jointly funded by the Foundation for Research Science and Technology and Fish & Game New Zealand. The results will be used to help Fish & Game NZ, Department of Conservation, and the guided tourism industry with the management of trout fisheries.

“More and more overseas anglers are coming here each year while New Zealanders are increasingly lured to the backcountry in search of large trout swimming in crystal-clear water,” say the researchers.

“Anglers, guides and fisheries managers are concerned about the increasing number of anglers visiting these rivers but everyone has a slightly different view on the effects this is having on the fishery.”

“Social surveys of anglers have shown the likelihood of meeting another angler on some rivers is high enough to make them go elsewhere.”

The researchers believe their work will help to ensure a high- quality backcountry fishing experience is available to future generations of kiwi anglers and tourists.

For further information: Dr John Hayes, Freshwater Fisheries Scientist, Cawthron Institute Tel 03 548 2319 (Wk), Tel 03 545 0294 (Hm) E-mail: johnh@cawthron.org.nz http://www.cawthron.org.nz/profiles_freshwater_jhayes.htm

Madeleine Setchell, Foundation for Research, Science and Technology Tel 04 4987806, Mobile 025 40 60 40, Email
madelein@frst.govt.nz

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