Zebra mussels for water quality improvement

Curonian Lagoon, Lithuania

The 1,584 km² Curonian Lagoon, is a popular destination for rural tourism. It also plays a critically important role for the Lithuanian commercial fishery. The water of one of the Curonian lagoon channels is used for most of Klaipeda's water supply.

However, the Curonian Lagoon is also very affected by anthropogenically-induced eutrophication. Over the past two decades, increases in nutrient concentrations and phytoplankton abundance have continuously been reported. According to the EU Water Framework Directive, all surface waters should reach a good ecological status by 2015. Reaching this objective will require multiple efforts, as the water quality of the Lagoon cannot be sufficiently improved through river basin management alone.

Several studies to date have addressed the potential for using zebra mussels in water quality remediation, given their filter-feeding capabilities. Zebra mussels have been an established population in the Lagoon for at least 200 years. They are abundant in the upper littoral to 3-4 meters depth and their estimated biomass is about 140,000 tonnes.

The idea for this regional activity is to assess the potential to contribute to surface water pollution reduction through zebra mussel cultivation. For this, CORPI will more specifically:

• Analyse the environmental conditions in the Lagoon with regards to ecological and economic threats and benefits of zebra mussel aquaculture development. This, among other things, evaluating the possible effects on hydrochemical paramaters in the Lagoon, the impacts of zebra mussel filtration and oxygen consumption on the ecosystem, and the biodeposition of suspended matter.
• Analyse the socio-economic perspectives of zebra mussel cultivation based on their growth rates, the accumulation of hazardous substances in their tissues and the level of infestation by parasites.
• Analyse cultivation technology, including modelling the optimal zebra mussel farm capacity and location, identifying stakeholders and selecting an appropriate site for construction.