Science Centres: Fisheries

Margaret McVeagh loads DNA into a gel

NIWA has been invited to participate in an international research network to DNA barcode 20 000 marine fishes by 2010.

Barcoding offers a simple means of unambiguously identifying different species. NIWA has a contract with Te Papa, funded by the Foundation for Research, Science & Technology, to use the barcoding method to identify so-called ‘problem fishes’, where it is hard to distinguish between species. For example, specimens of marine seaperch with a dark green back with black bands in Wellington Harbour are the same species as pale pink seaperch on the Chatham Rise. Recently, we established that there are seven species of pink maomao in the Pacific region, not three as previously thought.

Fisheries geneticists representing different regions of the world, including NIWA’s Dr Peter Smith, will meet in Toronto in June to establish the Global Fish Barcode Network. The project is sponsored by the Consortium for the Barcode of Life, which proposes to develop a universal DNA-based identification system for all animal species over the next 10–15 years. NIWA could be involved in barcoding about 1200 marine fish species.

The nasty bits

NIWA doesn’t just use DNA barcoding to identify whole specimens. We also use it to identify processed fish, eggs, larvae, and fish pieces – even ones that have been chewed, and stewed in stomach juice.

The Secretariat of the Pacific Community recently sent us frozen samples of partially digested gut contents from swordfish. In Peter Smith’s words, ‘we ended up with the nasty bits.’ We extracted the DNA from the delectable samples, then matched it against a database to identify precisely what those swordfish had for dinner. The menu turned out to be skipjack tuna, scad, and jack mackerel. This work was part of a Pacific-wide study of what large pelagic (open ocean) fish are eating.

We’ve also used DNA barcoding to support fisheries enforcement and consumer protection by testing whether fish species are correctly labelled.