A Preston man who has been missing in Ravenglass, Cumbria since Monday was on a holiday with his family.
John Allen, 76, from Fulwood, was last seen in the Ravenglass Estuary at 9am on Monday.
It is thought the keen walker may have been trying to help his dog out of the water.
A number of searches involving the coastguard, mountain rescue teams, police officers have taken place, with more than 100 people involved in the efforts.
Today his wife of 52 years Diana and the rest of Mr Allen’s family released a statement thanking people for their help in the search and the support they have received as this “most difficult time.”
They said: “13 members of the Allen family from Preston enjoyed a memorable few days last weekend in the beautiful Eskdale valley.
“John, a keen, capable, mountain walker, and the most senior Allen, took his dog for its usual morning walk on Monday morning - something he loved to do.
“It appears that for some unknown reason John got into difficulties whilst walking near the River Esk Estuary around Ravenglass and subsequently never returned from his walk.
“The search continues throughout the area and the family wish to express their deep gratitude to wider family, friends, the local community and numerous emergency organisations, in particular Cumbria Police and Coastguards, for their unrelenting, ongoing support at this most difficult time.”
Earlier this week Insp Mark Wear from Cumbria Police said it was “very out of character” for Mr Allen to be away for so long.
He added: “I would urge anyone who may have seen someone matching his description to get in touch as soon as possible.”
Mr Allen is 5ft 8”, of slim build and is bald.
He was wearing a green fleece, green suede trousers and walking boots.
On Wednesday police searching for Mr Allen received a hoax phone call reporting a body at Beach Road in St Bees.
The area was searched but officers now believe the call was a hoax.
A female officer fell on rocks on the beach and broken bones in her hand whilst searching.
A number of agencies have been involved in the search, including Cumbria Police, Coastguard, Cumbria Fire and Rescue, CNC, National Police Air Service, and mountain rescue teams.
Anyone who may have seen someone matching Mr Allen’s description is asked to call Cumbria Police on 101 and ask for the duty sergeant at Whitehaven Police Station quoting log number 59 of April 28.