Short- and long-term fluctuations in the size and condition of harp seal (Phoca groenlandica

• Main Authors: D. Chabot, G. B. Stenson, N. G. Cadigan
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Key words; Biological characterstics; body condition; body size; growth; harp seals; Arctic; Newfoundland; Harp Seal; Phoca groenlandica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.530.3941; http://archive.nafo.int/open/studies/s26/chabot.pdf

A total of 8 164 harp seals (Phoca groenlandica) were sampled off Labrador and northeast Newfoundland between November and May of most years between 1979 and 1994, a period during which the seal population increased in size. Data from an additional 640 seals were acquired from other authors (1976–79, 1988–92). By April, males grew to an average of 169.9 cm and 103.3 kg, about 4.7 cm and 4.7 kg more than females. Mass, sculp mass, core mass, girth, blubber thickness and even body length fluctuated significantly between November and May, with maximum and minimum values encountered in February and May, respectively. All seals older than 1 year displayed similar fluctuations. Juvenile males and females (<5 year) behaved similarly, but in seals of age ≥5 years, the females came back from Arctic waters in better condition than males. The drop in mass seen during the whelping period coincided with a drop in core mass, whereas sculp mass changed little or not at all. Using data for April to remove seasonal variability, young females (<5 years) were found to grow more slowly in both length and mass in the period 1990–94 than in previous observations in the same period in 1976–79, 1980–84 and 1985–89. Young males did not differ in growth rate between periods, but had lower length and mass at a given age in 1990–94 than seals from previous periods. Older seals of both sexes were in worse