Periodicity in foraging areas of leopard seals in the region south of Macquarie Island

• Format: Dataset
• Language: unknown
• Published: Australian Ocean Data Network
• Subjects: biota; oceans; EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES; ANIMALS/VERTEBRATES > MAMMALS; BIOSPHERE > ECOLOGICAL DYNAMICS > SPECIES/POPULATION INTERACTIONS > SPECIES COMPETITION; MIGRATORY RATES/ROUTES; USE/FEEDING HABITATS; RANGE CHANGES; POPULATION DYNAMICS; ACW; DATE; CONDITION; HAUL-OUT; HYDRURGA LEPTONYX; LATITUDE; LENGTH; LEOPARD SEAL; LOCATION; LONGITUDE; NUMBER OF SEALS; PACK-ICE EDGE; MACQUARIE ISLAND; PERIODICITY; SEAL; SEX; Hydrurga; Hydrurga leptonyx; Leopard Seal; Leopard Seals; Macquarie Island
• Online Access: https://researchdata.edu.au/periodicity-foraging-areas-macquarie-island/2816253

Progress Code: completed Statement: The data quality is variable between years, some years had dedicated data collectors and others did not - hence data were collected only sporadically in those years, if at all. The detail of information recorded on the sightings also varied between year to year, as did the format of the recordings. The format and the physical condition of the records resulted in some information on the sightings being omitted from this dataset due to illegibility and unreadability. The affect of this on the overall quality of the data would be minimal. Data collection began in earnest in 1948, but there are some sporadic records earlier than this dating back to 1900. For further information on the quality of the data, refer to the references below. --- Public Summary from Project --- Leopard seals are usually seen in the pack-ice where they pup on the ice and where they must first face life at sea. However at Macquarie Island, well to the north of the ice, for 50 years now there has been the odd phenomenon of 'Leopard seal years'. At seemingly semi-regular periods (~3-4 years) considerable numbers (can be greater than 100) of leopard seals arrive at the island; and then virtually none are seen for some more years. The periodicity of these arrivals has been striking. Thus it seems that young leopard seals (which is the group arriving in poor condition on Macquarie Island) suffer acute food shortages in the pack-ice zone every 3-4 years. This project will continue to record these events and tag and weigh the seals which come ashore. This will allow the long-term dataset to continue and give some more information about the seals which arrive. It is also planned to glue some satellite recorders to the seals so that their journeys after M.I. can be known. Data are collected when seals are seen on beach. Since the 1980s few seals have been seen so data are sparse but significant. Currently the dataset contains the number of leopard seals sighted at Macquarie Island each year and a record of ...