IMG_0799

IMG_0799

Observation - IMG_0799 - UK and Ireland. Description: A piece of rope was hanging in the River Nene from my boat and on removing it I found this what looks like an egg sac attached to end, it is about the size of a large goose egg. Any ideas what it is please.

A piece of rope was hanging in the River Nene from my boat and on removing it I found this what looks like an egg sac attached to end, it is about the size of a large goose egg. Any ideas what it is please.