Salinity shock as a biosecurity control: short-term exposure to freshwater as a treatment for fouling marine invasive species.

Description

Marine invasive alien species (IAS) can have profound economic and environmental impacts in introduced regions. The need to develop novel management methods for control of marine IAS has seen research into a number of treatment options that exploit the natural physiological tolerance limits common to marine species. However, as IAS have been shown to be better able to recover following environmental stress than similar natives, consideration of community tolerance and dynamics post-treatment is important. Salinity shock with freshwater has been shown to be an effective treatment option for a number of IAS, but there have been few studies which consider response of the biofouling community as a whole. An experiment was designed to test response and recovery of IAS and their associated communities following short-term exposure to lower salinity conditions. The experiments used biofouling communities grown on settlement panels suspended from floating pontoons in four Scottish marinas with environmental salinity conditions varying from high freshwater inflow to fully saline. Eight-week-old communities were subjected to low salinity conditions for one to four hours, then photographed and returned to the pontoons, and recovery monitored over an eight week period. Results showed significant variation in the biofouling communities between sites with different natural salinity conditions. The largest changes in biofouling community assemblages were seen in the marina with the most stable natural fully saline conditions, while little effect of treatment was observed in the marina with high freshwater inflow. Response varied between different IAS, with some species controlled by freshwater treatment and others increasing in abundance, possibly as a result of reduced competition. These findings highlight the importance of considering post-treatment processes and local community dynamics when planning control of fouling marine species using freshwater.

Period	17 Oct 2018
Event title	ICMB-X: 10th International Conference on Marine Bioinvasions
Event type	Conference
Conference number	X
Location	Puerto Madryn, ArgentinaShow on map
Degree of Recognition	International