Abstract
Every year, orphan harbor seal (Phoca vitulina) pups are admitted during the summer season at the Seal Rehabilitation and Research Centre (SRRC) in Pieterburen, The Netherlands. Severe weather conditions and human disturbances are often the main cause of stranding. Orphan pups are vulnerable since they are not able to fend for themselves. Due to their lactation physiology and duration,1 nutritional requirements,5,6 and often critical health status, rehabilitating these animals is a challenge. Since 1971, the SRRC has rehabilitated more than 2000 orphan pups, most of them still with the umbilical cord attached. Historically, the team has fed the seals with a herring-based formula, weaning the animals 14 days after arrival. This protocol and formula have always shown good results both in growth rates (54 g/day until weaning) and survival rate (84%). Recently, the SRRC has introduced a revolutionary salmon emulsion, produced initially for human consumption, as the base of the nutritional regime for the seals under rehabilitation. This salmon emulsion is per se considerably richer in caloric content (180–292 kcal/100 g) compared to the average of the herring-based formula (178 kcal/100 g). This led to a review of the nutritional protocol and a reduction in the amount of feedings and the advance of the weaning to day 13 after arrival. An evaluation of the growth and mortality rate data of harbor seal pups fed with this emulsion has shown an important increase of efficiency. Pups under this new feeding regime grow an average of 99 g/day and have a mortality rate of just 5%. Although this growth rate is still lower than the ones of wild-raised pups (400–700 g/day),1,3-5,7,8 the salmon emulsion and the feeding protocol followed by the SRRC has demonstrated to be more efficient than previous methods2,9. This information could be of help for other facilities that deal with orphan harbor seal pups.
Acknowledgements
The authors wish to thank Meat&Co for excellent technical assistance, and especially Patrick Koehorst. The authors thank the SRRC staff members, interns and volunteers for their work and support.
* Presenting author
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