Rescued seals 'survive in the wild'
Injured seals looked after by animal welfare officers have as good a chance of surviving in the wild as their healthy peers, according to a study.
Six seals being sent back into the wild were fitted with tracking equipment so researchers could measure their breath capacity while diving.
The St Andrews University study said the common harbour seals returned to the wild without any adverse effects.
It said they could swim and dive as well as normal, healthy wild seals.
The research was carried out with staff at the RSPCA East Winch Wildlife Centre and scientists from the Sea Mammal Research Unit at St Andrews.
Alison Charles, manager at East Winch Wildlife Centre, said: "We have always done everything possible to return sick and injured seals back into the wild, and give them the best chance of survival once released, but until now we have never had the scientific evidence to back this work up."
The six seals tracked included Skippy, a juvenile harbour seal washed up at a Norfolk beach. She was underweight and had several infected wounds on her neck and hind flippers.
After 155 days of treatment, she was released and monitored using the satellite tracking devices developed by Dr Bernie McConnell at St Andrews University.
The satellite transmitter, glued to the fur on the back of the seals' necks, allowed experts to remotely monitor their health for the first time.
The transmitters are usually lost when the seals moult, but for about six months after their release data was collected by scientists monitoring trends in their diving ability.
The data was then compared to the dive patterns of five wild adult harbour seals.
Ms Charles said: "Previous research had always shown that seals did survive after release, but it never gave an indication as to how well they were surviving and coping.
"Through this study we can clearly see that our rehabilitated seals could dive just as well as wild seals and this was a clear indicator of their health and strength when back in the open waters."
The study also found that the rehabilitated seal pups travelled significant distances once they were released.
Dr McConnell, a senior research fellow at St Andrews University, has been monitoring the movement and behaviour of marine mammals for more than 25 years.
He said: "The important finding here is that on release all rehabilitated animals immediately demonstrated diving capabilities that persisted during their tracking periods.
"This behaviour was similar to the diving capabilities of apparently healthy adult seals.
"While we assume that the debilitated seals were released in an apparently healthy condition, there could be concern that captivity per se could impair dive capability. However, we find that this is not the case.
"There was no statistically significant difference between the behaviour of rehabilitated seals and healthy adult seals, indicating no evidence that short-term survival was less in the rehabilitated group."