When we think about the most exciting creatures Canada has to offer, your first thought does not immediately jump to the freshwater mussel. That’s what I thought too, until I started learning about them. My name is Kareina D’Souza and I have loved animals my entire life, which is why I pursued a degree in Zoology from the University of Guelph. I spent most of my time in Guelph fascinated by sharks, lions and other large vertebrates. The animals I have been historically been intrigued by are bigger and as I used to think, more exciting than freshwater mussels. However, these little animals play a huge part in our aquatic ecosystems. They use their siphons to filter bacteria, algae and other particles out of the water, and are able to filter up to 40 litres of water a day. Their ability to filter helps improve water quality and they also serve as an important food source for many groups including fish, reptile, birds and mammals. They collect toxins in their body, which makes them early indicators of environmental degradation. Unfortunately, this makes freshwater mussels sensitive to pollution and habitat destruction and they are currently the most endangered group of invertebrates in Canada. Out of the 41 species currently found in Ontario, 14 are listed as Species at Risk.
In order to help protect freshwater mussels, we must be able to catalog their diversity in water bodies and protect these areas. Currently, mussel surveying is time and resource intensive so new ways of assessing biodiversity are being tested. One new type of assessment is environmental DNA (eDNA) studies to detect the presence of species in an aquatic environment. This approach is effective when a large sampling effort is required to assess species diversity and morphological identification is difficult, as is the case with freshwater mussels. However, before we can use eDNA studies to track changes in endangered populations we must first establish a DNA barcode library.
This summer, BIO will be teaming up with several conservation authorities in order to complete the barcode reference library for freshwater mussels. This is no easy task, because freshwater mussels are in substantial decline and in many cases, unable to be collected as voucher specimens. In order to collect the barcodes, we will be using non-invasive sampling which will allow us to collect samples without harming the mussels. Our procedures involve sampling the mussels by collecting periostracum and visceral samples through the use of sterile culture swabs. This method allows us to obtain sufficient DNA without harming the mussels or removing them from their environment for more than a few minutes. In a small pilot project in 2014, BIO worked with Kari Jean and Hope Brock at the Ausable Bayfield Conservation Authority to optimize field and laboratory techniques. Our preliminary work on this project has generated barcodes for 50% of the freshwater mussel species in Ontario and we aim to complete the library by the end of the summer.
I’ll be lucky enough to spend my summer in various water bodies in Ontario learning about these amazing creatures and using non-invasive sampling to create a complete reference library for the Barcode of Life Database. Stay tuned for more stories about my adventures in the field!