Postrelease dive ability in rehabilitated harbor seals

  • Published source details Morrison C., Sparling C., Sadler L., Charles A., Sharples R. & McConnell B. (2012) Postrelease dive ability in rehabilitated harbor seals. Marine Mammal Science, 28, E110-E123.


This study is summarised as evidence for the following.

Action Category

Rehabilitate and release injured, sick or weak marine and freshwater mammals

Action Link
Marine and Freshwater Mammal Conservation
  1. Rehabilitate and release injured, sick or weak marine and freshwater mammals

    A controlled study in 2003–2004 in an estuary, The Wash, Norfolk, UK (Morrison et al. 2012) found that six sick or injured harbour seal Phoca vitulina pups that were rehabilitated and released back into the wild survived for at least three months, were tracked for similar durations and had similar dive behaviour to wild seals. Six rehabilitated harbour seal pups were tracked for 100–175 days after release. On average, the six rehabilitated seals were tracked for similar durations (122 days) to five wild seals (150 days), indicating similar short-term survival. Average dive durations and percentage of time at-sea spent diving were also similar for rehabilitated seals (4.0 minutes; 81.6%) and wild seals (4.1 minutes; 81.5%). In September–October 2003, six juvenile seals (aged 2–3 months; four males, two females) were rescued with wounds and/or respiratory problems. After 134–169 days of rehabilitation, the six seals were satellite-tagged and released in an estuary in February 2004. Five wild adult harbour seals (one male, four females) were caught in the estuary and satellite-tagged in February 2004. Data were collected for each of the 11 seals during 100–170 days in February–August 2004. Average dive durations were adjusted according to body mass.

    (Summarised by: Anna Berthinussen)

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