Tuesday, February 22, 2011

The Eyes Don't Have It

Its a long tale on how this grant and research came to be. But as usual its best to start at the beginning. In 2007 I completed my PhD, which investigated nocturnal fish and asked the broader question 'how do fish survive and function in darkness where the use of vision is limited'? This question has always interested me as I have always had a fascination with the deep-sea and those fish that live in extreme environments.

After my PhD I moved to Rhode Island and began a one year postdoc where I looked at the nocturnal feeding behaviour of a Lake Malawi Cichlid. During this time I became aware of the many alien fish species in the United States, and the large impact they are having on the local freshwater ecosystems. The most notable examples are Carp, the Ruffe and the Round Goby. Because my background was in sensory ecology I noticed that all these species were non-visual sensory specialists. Or to put it more simply - they can feed and function without using vision. Thus, habitats that were extremely murky would be no problem to survive in for these fish. Which leads me to the next link in the chain. I also became aware that most invasions by alien fish occurred within these very murky habitats, and it was here that the idea was born. Do turbid or murky ecosystems provide an invasion pathway for exotic non-visual fish? 

In 2010 I was lucky enough to be awarded a grant by the Foundation for Research in Science and Technology (NZ) to investigate this very question. At this time I was already working in Canada at the Memorial University of Newfoundland under the guidance of Professor Mark Abrahams. However, at this stage I was investigating predator-prey interactions between two marine fish. But with a quick change of focus I found myself returning home to New Zealand to begin the first phase of my research. My goal for the summer was to look at biodiversity in turbid and clear freshwater rivers and see if in fact non-visual species increased in the murky sites. 

Setting up any fieldwork is not without it's problems and my research was not going to be exempt from this rule. Our initial problem was site selection and getting sites that were close enough that other factors couldn't account for any differences in fish biodiversity. For example propagule pressure presented a problem because we needed to make sure that one site didn't have more exotic fish simply because they were been released there more often. After looking through historical data, and talking to many people in the know, we found three sites that seemed appropriate for what we wanted to do. The sites included a highly turbid river emptying into the relatively clear Waikato River. The Waikato River is New Zealand's largest river and the hub of exotic fish invasions. The demarcation line between the two rivers is very strong with one side been turbid, the other clear. We would simply need to sample on either side of the demarcation line with fyke nets and minnow traps and look for differences in fish populations.


To Be Continued.........

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