RSPCA officers are “monitoring” a seal which is stranded on the bank of the River Welland in Spalding.
The seal was first spotted on Wednesday when animal rescue crews from fire stations at Lincoln, Grantham and Corby Glen attempted to get it back into the water.
However the next day the seal was back on the bank.
Several readers have contacted the Lincolnshire Free Press, concerned about the animal, including one man who claimed he had seen people throwing rocks at it.
Nicola Walker, of the RSPCA, said: “We went down to rescue the seal last week but it was still fairly active and it went back into the water.
“Our officers have been down there several times since to monitor it but it’s almost impossible for us to catch the seal.
“We’ve not had any reports of people mistreating it and we will continue to keep an eye on it.”