Red Throated Diver Survey

Red throated diver survey: by-catch of birds in drift nets in the Thames 

The Red-throated diver (Gavia stellata) is a designated feature of the Outer Thames Estuary SPA. It is estimated the site supports over 18,000 overwintering individuals, representing 38% of the overwintering population in the UK. Individuals are usually grey-brown in colour but develop a red-throat during the breeding season. During the non-breeding season Red-throated divers remain on the water rafting and fishing throughout the Outer Thames Estuary.  

Static and drift net fisheries have been shown to be a hazard to diving seabirds globally with some studies reporting Red-throated divers amongst the casualties. In light of this best available evidence, entanglement in netting was identified by Natural England as a moderate risk to the designated Red-throated diver wintering population in the Outer Thames Estuary SPA.

Kent and Essex IFCA conducted surveys along with Natural England in winter 2011-2012 and 2012-2013 to gather data on the scale of netting by-catch of Red-throated divers in the Outer Thames Estuary SPA. KEIFCA Conservation Officers boarded fishing vessels undertaking netting activities in the SPA 40 times over the two winter survey periods. Netting activity was recorded along with the number of Red-throated divers caught as by-catch by set and drift netting and the effect of disturbance by fishing vessels and set nets on the birds.

No Red-throated divers were observed as by-catch in both winters and disturbance to the birds by small fishing vessels operating in the Outer Thames Estuary SPA was found to be negligible.