A rescue plan is being devised for a dolphin which has taken up residence in Maryport marina in Cumbria.
The dolphin has been in Maryport marina for more than two weeks
The lone male bottlenose dolphin - nicknamed Marra by locals - has been in marina waters for more than two weeks.
Experts initially believed the dolphin could have been injured or ill, but a monitoring exercise seems to suggest it is probably disorientated.
They want to avoid what happened to a whale that died after it became stranded in the River Thames on Friday.
The use of special underwater speakers to coax the animal back out to sea have so far had no effect.
A team from the British Divers Marine Life Rescue group (BDMLR) have been brought in to advise local officials on the best course of action.
A spokesman for the group said: "The dolphin swam about 500 yards up the River Ellen and through the lock gates into the marina.
"Initially there was a lot of concern over the dolphin's condition, but it seems to be fit and healthy.
"Behaviour experts have been informed and we are awaiting assessment by them too.
"Large crowds of people flocked to the marina last weekend to watch the dolphin playing."
Bottlenose dolphins are protected under the Wildlife & Countryside Act and any harassment is illegal.
Onlookers were warned last week when some began hurling empty beer cans at the animal.
The BDMRL spokesman added: "A possibility is that the dolphin is unsure about swimming through the lock gates or its echolocation is hitting the bank opposite the lock gates and therefore does not realise that is the exit.
"Sometimes the hardest choice is to do nothing, but this can often be the best and most appropriate course of action.
"BDMLR directors and experienced medics are on standby in case they are needed to help with the rescue attempt.
"This may mean draining the marina at low tide and then catching Marra up and taking it back out to sea using pontoons."