Madison Young, from Wooler, is raising funds for a wildlife rescue centre which takes in and treats injured and sick seals.
She started her challenge at Berwick and Spittal on Monday and is working her way south to Holy Island, Bamburgh, Seahouses, Beadnell, Boulmer, Amble, Cresswell and Newbiggin over the course of a week.
Her mum, Lynn is a volunteer marine mammal medic for British Divers Marine Life Rescue, the UK's leading marine mammal rescue organisation.
She said: “Madison loves doing beach cleans so we do them quite often but this time she wanted to raise some money so we’re doing seven days in a row along the whole coast.
"Many of the seals which are taken in from Northumberland – and there have been quite a lot after the recent storms we’ve had – go to Hessilhead Wildlife Rescue rehabilitation centre in Aberdeenshire for treatment so she wanted to support them.”
Lynn added: “I’m a marine medic and Madison has often been with me on seal call-outs. She never gets near the seals but she helps out in getting members of the public with dogs to keep their distance and make sure they’re on leads.
"She also knows her stuff about seals so is happy to pass that on to people wondering what we are up to.”
On the first day of her challenge she picked up discarded fishing gear and nets, rope, food and drink containers, plastic wrappers, a tyre and even a steering wheel.
The Farne Islands are home to one of England’s largest grey seal colonies, with smaller numbers often spotted at Coquet Island and Holy Island.
Marine pollution, especially ghost fishing – what fishing gear does when it has been lost, dumped or abandoned – is a growing concern.
Madison said: “I love the ocean. I often help my mum rescue wildlife, seals in particular and it makes me sad when they are trapped, entangled and hurt in our litter and lost fishing gear.
“Hessilhead Wildlife Rescue have helped save the lives of so many seals and your donation will help them to make poorly seals better.”
She has already raised £660 of her £750 target.
To donate, visit https://www.justgiving.com/fundraising/Jane-Hardy19