Over the course of March, our field team was busy undertaking weekly surveys to identify the presence of a protected fish species known as smelt (Osmerus eperlanus) in the Thames Estuary on behalf of the Environment Agency. Weekly trawl surveys were undertaken in the vicinity of Cooling Marshes, Kent with the objective of providing further information regarding smelt migration in the Estuary.
Smelt are small, silvery fish which migrate from the sea into estuarine rivers to spawn. Upstream migration is thought to take place between February and March, and timing may be tied to water temperature. Smelt aggregate in this part of the estuary before progressing upriver to spawn. As such, our team monitored the presence of the fish in a series of mid-water trawls together with measurement of environmental conditions such as water temperature, salinity, pH and oxygen saturation within the area of interest. Though generally a little chilly, our team had an excellent opportunity to observe the behaviour of these small and rare fish in one of the busiest but most interesting estuaries in the country.
