Te Papa has an internationally important fish collection, notably because of its capacity to hold large numbers of large specimens, and also because some of these fishes were collected over 100 years ago.
Fish experts Andrew Stewart and Carl Struthers explain how these ‘time capsules of data’ are central to a current University of Otago research project.
A truly significant fish collection
As part of the National Science Challenges Sustainable Seas project, PhD student Leo Durante from the Marine Science Department at Otago University, visited Te Papa to sample preserved commercial fishes housed in the National Fish Collection (NFC) at Tory Street, Wellington.
Te Papa has the only New Zealand collection of fishes with enough specimens, species, area coverage, time coverage, and size ranges, to allow analyses at both the community level and the oceanic basin scale along the South Island East Coast, using specimens of commercial size.
These old specimens are time capsules providing unique data that cannot be accessed elsewhere.
Current research
Leo’s focus was on resolving changes in the trophic position (where they sit in the food chain) of marine fishes, which are managed under the Quota Management System (QMS), how they are connected along the east coast of New Zealand, and how these connections may change across different habitats.
This project is the first attempt to discover the connectivity of QMS fish species along large-scale seascapes.
Leo was also hoping to see how these connections may have changed over the last 100 years. The oldest specimens he sampled in the NFC are a leatherjacket and stargazer, both collected almost 100 years ago in 1919!
Research methods
To answer these research questions, Leo examined isotopes ratios in tissue samples taken from selected specimens over different historic time periods, and will compare these to recently collected samples.
Food eaten by these fishes contains naturally occurring isotopes (notably carbon and nitrogen), which are retained in the muscles. The different ratios are an indication of where the fishes have been feeding within the food chain.
Leo took tissue samples from a total of 245 specimens covering 17 commercial species, including ling, hapuku, hoki, and orange roughy. The largest fish sampled was nearly a metre long, and most were over 500 mm. Due to their large size, value, and difficulties of sampling, commercial species in these numbers are not usually kept by other museums.
Leo’s research is a perfect example of how historical natural history collections can be re-examined, using new scientific techniques as they develop, in order to answer important modern day questions about our natural resources.