AFBI Hosts Eel Outreach Day at Castle Espie

The Agri-Food and Biosciences Institute recently held its second eel outreach day at the Wildlife and Wetlands Trust, Castle Espie.

Staff from the Fisheries and Aquatic Ecosystems Branch in AFBI have established a Glass Eel counting site at the main exit from the freshwater ponds at Castle Espie to Strangford Lough. With 5 years of data now collected, this site has been adopted for international reporting as one of a network of UK index sites for eel recruitment.

The event ran in parallel to the annual arrival and entry to freshwater of the transparent juvenile eels,  after their long  migration from the Sargasso Sea via the Gulf stream and North Atlantic Currents. As it turned out, the first catch came on the morning of the event, having been delayed by two months of near freezing freshwater temperature; the eels sensibly waiting in the sea for spring to warm up.

When glass eels first arrive they are totally transparent apart from their eyes – a good idea when everyone else in the ocean wants to eat you. Within a few months, the internal organs, bones and then the flesh darken and the eel takes on the normal yellow-brown colour of the freshwater phase. Their hypnotic swimming motion and communal resting behaviour, with many little heads poking out of a single resting place, make for a fascinating display of this creature’s early life.

There was considerable interest in the AFBI display with over a hundred visitors to the stand, and the usual range of obvious and not so obvious questions.

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