One of the main aims of the expedition is to collect specimens of fishes, invertebrates and plants for Auckland Museum’s collections, as well as for the other museums. Museum reference collections are a fantastic treasure trove, which biologists around the world come back to use time and time again.
When biologists discover a new species, for instance, they lodge a voucher specimen in an authorised collection – this is ‘the’ definitive example of that animal. A specimen of a new record provides proof that a fish really is the fish everyone says it is. And in future people can come back to specimens for genetic analysis or any other purpose, say comparing levels of pollution at different times.
There are many varied ways of collecting different kinds of critters, and I’ll tell you about some of them over the next few days. The fish team have been focusing on using rotenone to anaesthetise fish so they can catch them in scoop nets.
Rotenone comes from the root of a plant, and similar ground plant roots have been used for thousands of years by people around the world to help catch fish. First up, Tom and the fish team choose what kind of place they want to sample – a shallow sandy spot will have many different kinds of fish to a deep cliff face, for example. Then Tom and Ged make the first dive to put the rotenone at the first ‘station’.
Tom Trnski putting rotenone in the water to anaesthetise fish © Richie Robinson
As you can see in Richie’s great photograph of Tom in action, the effect is initially quite dramatic, but the rotenone very quickly disperses into the water, and within about an hour has become so diluted it is no longer having any effect. Teams of divers take turns at the station to gather up all the stunned fish and they’re taken back to the boat for sorting and cataloguing.
The thing with diving is that each diver can only safely spend so much time in the water at certain depths, so one of the key things about running a rotenone station is careful planning and good team work – and it’s working well. In the next blog I’ll share some of the first day’s exciting finds – they certainly kept the fish team happily working late last night!
