Research aims to restore mussel species
25 Mar, 2008
Source: Dominion Post, March 2008
Restoration Ecology Masters student Hannah Rainforth is examining the impact of sediment levels on freshwater mussels’ feeding behaviour.
Anecdotal evidence suggested the supply of freshwater mussels (kakahi) was diminishing in the Whanganui River, where once they were plentiful.
The mussels were measured for how much water they could pump through their systems (clearance rate) and how many particles of sediment were removed from the water (filtration rate).
One theory was that increased sediment could clog the mussels’ gills and stop them from feeding. This has happened overseas with different species.
“Filtration rates can change depending on factors such as flow, oxygen, food and sediment levels in the water,” Hannah says.
Green lipped mussels in New Zealand have been recorded filtering sediment in much higher concentrations than overseas mussel species, but it is still unclear why this is the case.
The New Zealand freshwater mussel’s filtering ability is possibly the best in the world Hannah adds.
“They’re a very long lived species, living for over 30 years, so any effects on their population are quite long term and slow to be noticed.
“For me, the driving factor is ultimately how to help these species and how to restore them to the river.”
