Several articles were published in the Journal of Wildlife Rehabilitation Fall 1999, Col. 22, No. 3:-
- Wilson, S.C. 1999. Overview of harbour seals, their behavior, and previous rehabilitation attempts. J. Wildlife Rehab. 22(3): 3-4.
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- Wilson, S.C. 1999. Radiotelemetry study of two rehabilitated harbor seal pups released close to the natural time of weaning in the wild. J. Wildlife Rehab. 5-11
Abstract - Two newborn harbor seal pups in County Down, Northern Ireland, were found abandoned in 1997. Both pups were reared in a captive environment on an artificial formula intended to simulate the constituents of natural seal mothers' milk, with the intention of releasing the pups as close as possible to the natural time of weaning in the wild.
The pups grew steadily, each achieving an 11 kg weight gain in approximately one month. In early August each pup was fitted with a head-mounted VHF radio-transmitter and released at Millin Bay, County Down. Subsequent radio-tracking revealed that both pups survived, and one of the pups was occasionally seen until the end of the following May. Both pups foraged over an area of about 15 km radius, within the usual range previously found for wild harbor seal pups tagged locally.
- Wilson, S.C., Corpe, H.M. & Kennedy, S. 1999. Radiotelemetry study of a harbor seal pup released after a brief postweaning rehabilitation period. J. Wildlife rehab. 22(3): 12-16
Abstract – A postweaning harbor seal pup was taken from a haul-out site at Minerstown in County Down, Northern Ireland, for rehabilitation, owing to her small size and emaciated appearance. She was fed a high-fat/high-protein liquid diet for three weeks and then fitted with a head-mounted VHF radio-transmitter and released, weighing 15.5 kg.
During the next six weeks, radio-tracking found her diving off the County Down coast, moving within the rangMinerste known to be used by wild weaned pups from Minerstown. Between four and six weeks after release she was sighted on three occasions at the Minerstown haul-out site in the company of other postweaning pups, and each time appeared to be in good health and approximately the same size as the other pups. Two weeks later, however, she stranded with a swollen shoulder and fore-flipper; despite veterinary treatment, she died three days later. Postmortem examination revealed a fracture of the left ulna and parasitic pneumonia. Observations during the week prior to her stranding suggest a gradual deterioration in her condition stemming from the trauma to her shoulder, which was most probably the result of collision with a boat.
- Wilson, S.C., Johnston, T. & Corpe, H.M. 1999. Radiotelemetry study of four rehabilitated harbor seal pups following their release in County Down, Northern Ireland. J. Wildlife Rehab. 22(3) 17-23.
Abstract – Four harbor seal pups stranded in County Down, Northern Ireland, in 1995 and 1998 were rehabilitated in a public aquarium facility. They were fed on liquidized and solid herring diet and gained approximately 0.05 kg/day for about the first 10 weeks and subsequently about 0.3 kg/day until their release at about four months of age.
The seal pups' progress after their release was followed by radio-telemetry for three months. Two pups survived this period, one died of unknown causes near the release site about a week after release, and one disappeared shortly after release and was not relocated. One of the surviving pups emigrated from the area within four days of her release and took up residence in a shallow commercial harbor for two months before eventually emigrating further south to Dublin Bay. The other returned only infrequently to the County Down coast, but was seen amongst a local haul-out group after 12 weeks, and was apparently healhty and well grown.
- Wilson, S.C. 1999. Postscript: Conclusions relating to harbor seal pup rehabilitation from the case studies. J. Wildlife Rehab. 22(3) 24-25.
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- Wilson, S.C. Rehabilitation of harbour seal pups by the 'fast-track' method.
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Abstract – Ten harbour seal pups stranded on the Co. Down coast between 1996 and 2002 were rehabilitated accccording to a new 'fast-track' method. The aim of developing this method was to enable the pups to gain sufficient weight during a 3-6 week period so that they could be released during the natural post-weaning period of pups in the wild. The rehabilitation pen contained a bath (in 1996-97) ans subsequently a pool (approximately 1x2m are and 1m deep) surrounded by a haul-out area and a large kennel. Eight of the pups (in four different years) were neonates and were kept in pairs in the pen. The two pups generally followed each other around the pen, played together in the bath or pool and slept together in the kennel. The other two pups were taken, in two separate years, at approximately six weeks of age and were therefore kept singly. All the pups were fed exclusively on a high fat liquid formula, to which digestive enzymes were added for all except the first pup. All pups were tube-fed and one pup also suckled from a baby's bottle. They were never fed on whole dead fish (so as not to interfere with the development of their natural foraging behaviour after release). The average weight at the start of rehabilitation was 8.1 kg (range 7.25-12.5 kg). The mean daily weight gain was 0.20 kg for the first pup and between 0.26 and 0.55 kg for the subsequent nine pups. The average weight of all 10 pups at release was 20.4 kg (range 15.5-23 kg), length nose to tail 91.7cm (range 85-103 cm), maximum girth 71.4 cm (range 61-77 cm) and girth/length ratio 0.77 (range 0.72-0.86). On the day of their release, all the pups were fitted with a head-mounted VHF tag and were dye-marked on the fur of the back. All ten pups were found to survive the transition to the wild. They were all observed or tracked when engaging in normal foraging dives. Seven of the 10 pups were observed to haul out and/or swim with other seals.
It was concluded that this 'fast track' method was successful in terms of the pups' post-release survival and development of natural behaviour. Therefore the usual rehabilitation practices of training pups to take solid dead fish and retaining them for 4-5 months for greater weight gain are thought to be unnecessary and probably counter-productive.