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Snapper DNA to shed light on fishing-induced evolution

Snapper. Photo from Meredith Lowe and Crispin Middleton, NIWA

Posted: Thu, 3 Nov 2016

Marsden funding has been awarded to Dr Peter Ritchie from Victoria University of Wellington’s School of Biological Sciences and Dr Bastiaan Star from the University of Oslo, Norway, who lead one of several research projects in the rapidly growing field of ancient-DNA technology.

Dr Ritchie and Dr Star’s project will use DNA extracted from snapper bones in ancient Māori middens (dating back to the 15th century) to show how the genetic diversity of these fish populations has changed over time.

Snapper is New Zealand’s most important fisheries species and has been exploited since Māori first arrived around 700 years ago. Industrialisation of fishing during the last century nearly caused snapper stocks to collapse in the 1980s, until controls were introduced to halt their decline. Today, snapper continues to be caught in large numbers by both recreational and commercial fishers.

Fishing typically targets larger individuals, which may increase the reproductive success of small fish that mature early. Indeed, many studies have reported a decrease in the average size of fish, the age at which they mature, and significant loss of genetic variation. However, it is not known whether these changes are an evolutionary adaptation or a direct response to over-fishing.

By comparing DNA from ancient snapper bones with DNA samples from heavily-fished modern stocks, Dr Ritchie will establish whether there is a link between over-fishing and genetic selection. They will also test whether genetic diversity has been depleted in current populations, and compare their findings to studies in Atlantic cod, another fish that has suffered from commercial over-fishing.

This research will make a significant contribution to our understanding of human impacts on the environment, and could help preserve the long-term future of fish stocks.


Total Funding: $830,000 (excl. GST) over 3 years

Researchers: Dr Peter Ritchie, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140