Energetic consequences and implications for food consumption models when feeding on various sizes of cod in harp seals (Phoca groenlandica) (original) (raw)

The effect of feeding on the metabolic rate in harbour seals (Phoca vitulina)

Journal of Comparative Physiology B, 1994

The heat increment of feeding was estimated in harbour seals (Phoca vitulina). Seals were given different amounts of herring, ranging from 0.8 to 2.65 kg. The caloric content of the herring ranged from 6575 to 12560 kJ.kg 1 depending on time of year. Metabolic rate increased within 30 min after feeding, and the magnitude and duration of heat increment of feeding depended on the size of the meal and the caloric content of the herring. Measured heat increment of feeding was up to 14.9% of gross energy intake and metabolic rate increased as much as 46% above resting, postabsorptive metabolic rate for 15 h duration in a harbour seal with a body weight of approximately 40 kg.

Seasonal Changes in Food Intake of Harp Seals (Phoca Groenlandica) at 69°N

Marine Mammal Science, 1994

Food intake (PI), body mass (BM), and compartmental growth were recorded for 12 mo in four captive 2–4‐yr‐old male harp seals (Phoca groenlandica), exposed to an artificial light regime that closely resembled natural day length at 69°. In early May before molting, both FZ and BM decreased in all four animals. Total body fat (TBF) declined from 51% of BM in March (n = 4) to 30% in August (n = 2), while total body water (TBW) concomitantly increased from 37% to 51% and total body protein (TBP) from 11% to 17%. In July FI started to increase, while BM started to increase in August. TBF increased while TBW and TBP decreased from August, all three parameters reaching a stable level in October at 47%, 39%, and 12%, respectively. Thereafter, body composition was maintained rather constant until May. Between October and March/April FI fluctuated for all animals, while BM showed a fairly steady increase. Average daily amount of capelin consumed was 2.67 kg·d−1, equivalent to 25,600 kJ·d−1, o...

Sources of error in estimating food requirements of seals

Polar Record, 1988

Grey seals Halichoerus grypus are common along some parts of the coasts of the North Atlantic Ocean, and many believe they compete with man for common food resources. This also applies to other species of pinnipeds. Sergeant (1973) suggested an estimate of annual weight of food items eaten by the northwest Atlantic population of harp seals Phoca groenlandica, and later food uptake and growth have been studied both in captive ringed seals Phoca hispida (Parsons 1977), harp seals (Keiver and others 1984), grey seals (Ronald and others 1984), and harbor seals Phoca vitulina (Boulva and McLaren 1979). In these studies, however, the animals were either not fed as much as they desired, photoperiod was either not controlled or did not parallel natural changes, and/or the studies lasted only for a short period of time. In the present study we have recorded daily energy intake and growth in a captive grey seal over a period of 3 years under semi-natural light conditions, and exposed important potential sources of error in experimentally estimating energy requirements of northern pinnipeds.