Alicia Catlin

Environmental Monitoring Scientist

You can tell the health of a stream by the bugs that live in it.

I monitor about 150 stream and river sites in our region every summer. The most important thing we collect is an invertebrate sample. We send them to an external agency and they process and identify all the macroinvertebrates. Bugs are good indicators of stream health. Each is given a tolerance score of 1 to 10. A 1 is very tolerant to pollution, and a 10 is very intolerant – they need clean water and are found at more pristine sites.

We measure and collect a whole range of parameters. We look at things such as instream habitats, substrate (the sandy, cobbly stuff at the bottom of the stream), macrophytes (aquatic plants) and periphyton (algae). We measure the width and depth of a stream, and look at canopy cover, erosion, sedimentation, fencing, land use … a whole bunch of stuff.

Every council is required to monitor their waterways, but each council can design their own monitoring network. We have quite a complex monitoring system – it’s the second biggest in terms of the number of sampling sites, behind Canterbury.

Our network is made up of reference sites, what we compare other waterways to and long term and random sites. Random sites are more to see what the main pressures are, to see what is having the biggest effect on our waterways so we can try and address that at other sites.

We have 25 pristine sites that have no interference in any way by humans – there’s nothing there but native bush. Fifty are long-term sites that we follow over time to see the trends every year, and there are 180 random sites that we rotate to look at the state of our region.

Our streams are a mixture of deep to shallow, very swift to no flow, full of algae to none, with various plant life.

There are range of things that are affecting our waterways. It’s hard to pinpoint one thing. It’s a combination of habitat loss, increasing sedimentation, exotic pest species competing with our native species, increase in agriculture, dairying and urbanisation as well.

I love my job. It probably goes back to spending every summer since I can remember at Lake Taupō. We would camp for at least three to four weeks over the school holidays. We would go trout fishing, and Dad would take us spotlighting for koura, and set up traps for bullies. I grew up on a farm so I was always outside getting my hands dirty. I didn’t want to be in the office all the time.

I am very passionate about our freshwater environment and where we will focus management in the future.