Research @ Otago - Rebecca McMullin

Rebecca’s research focuses on tracking the flow and fate of waste materials from salmon farms through food webs in the Marlborough Sounds.

Salmon aquaculture involves the input of large quantities of feed into sea farms, which in turn results in the production of organic and nutrient wastes that have the effect of increasing the ecological footprints of the farm. This may have consequences for the connectivity of food webs within the farm's ecological footprint.
 

Bagging and labelling samples

With help from a team of researchers in the Department of Marine Science, Rebecca has collected key species of fish, macroinvertebrates and benthic infauna (small invertebrates that live in the sediment) from around salmon farms in the Marlborough Sounds. These samples are now being processed and analysed to determine the proportion of organic matter each organism sources from farm waste relative to the proportion they source from natural marine sources such as macroalgae and phytoplankton.

Collecting samples from a salmon farm in the Marlborough Sounds

Rebecca has also set up mesocosms (like miniature ecosystems) at Portobello Marine Laboratory that will allow us to measure parameters that are useful for modelling the real-world system in the Marlborough Sounds.

Mesocosm set up at the Portobello Marine Laboratory

Ultimately this research will be useful in minimising negative impacts of aquaculture on natural ecosystems.