NIWA calls on citizen scientists for grey mullet survey

New Zealand’s leading freshwater and estuarine research body is harnessing the national curiosity about ecology to find out more about grey mullet.

Launching a survey on the abundance and location of the popular eating fish, the National Institute of Water and Atmospheric research (NIWA) calls on ecologically minded New Zealanders to get involved by providing their observations of this fish in its natural habitats.

Survey information

Project leader Mark Morrison says survey information will be welcome from all users of New Zealand’s outdoors – fishers, boaties, hunters, farmers, foresters, trampers, dive club members, Fish and Game members, rangers, and others. “This is a national survey, which extends well beyond grey mullet’s well known northern New Zealand estuary strongholds,” he says.

“Fish observations, and even information on where fish are not seen, will contribute to a robust survey. Historical accounts of fishing or unusual records of grey mullet are valuable too,” he says. “These could be things like personal natural history diaries, photographic records, or fishing logs. Photographs would be especially useful,” he says.

Grey mullet (Mugil cephalus) is a cosmopolitan species found around the world.

The grey mullet

Genetic data suggests that 14 ‘cryptic’ (only revealed through genetics) species exist globally, and in New Zealand, grey mullet support important commercial, recreational and customary fisheries with about 800 tonnes of grey mullet landed commercially each year, mainly in the upper North Island.

However, grey mullet are found around the entire North Island, and as far south as the Nelson/Blenheim region, with occasional reports from places even further south such as the Waimakariri River north of Christchurch.

Current evidence suggests that all juveniles start off in estuarine nursery habitats. With size and age they disperse widely across estuaries, freshwater systems such as lakes and rivers, off exposed surf beaches, and around coastal bays and islands, including many sheltered shallow-water reefs.

To contribute to an ongoing research programme about the abundance of grey mullet and where they are found, especially outside of their northern New Zealand estuary strongholds, NIWA is distributing a questionnaire and survey form inviting anyone spending time in New Zealand’s freshwater, estuarine or coastal environments to report their sightings and numbers of grey mullet.

More information

The Grey Mullet Survey will run until the end of September. Download the grey mullet survey form.

Grey mullet survey form (PDF 500 KB)