INDICATOR DEFINITION Count of all adult females, fully weaned pups and dead pups hauled out on, or close to, the day of maximum cow numbers, set for October 15. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Elephant seals from Macquarie Island are long distance foragers who can utilise the Southern Ocean both west as far as Heard Island and east as far as the Ross Sea. Thus their populations reflect foraging conditions across a vast area. The slow decline in their numbers (-2.3% annually from 1988-1993) suggests that their ocean foraging has been more difficult in recent decades. Furthermore, interactions with humans are negligible due to the absence of significant overlap in their diet with commercial fisheries. This suggests that changes in 'natural' ocean conditions may have altered aspects of prey availability. It is clear that seal numbers are changing in response to ocean conditions but at the moment these conditions cannot be specified. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: Five beaches on Macquarie Island (lat54 degrees 37' 59.9' S, long 158 degrees 52' 59.9' E): North Head to Aurora Point; Aurora Point to Caroline Cove; Garden Cove to Sandy Bay; Sandy Bay to Waterfall Bay; Waterfall Bay to Hurd Point. Frequency: Annual census on 15th October Measurement Technique: Monitoring the Southern Elephant Seal population on Macquarie island requires a one day whole island adult female census on October 15 and a daily count of cow numbers, fully weaned pups and dead pups on the west and east isthmus beaches throughout October. Daily cow counts during October, along the isthmus beaches close to the Station, provide data to identify exactly the day of maximum numbers. The isthmus counts are recorded under the long-established (since 1950) harem names. Daily counts allow adjustment to the census totals if the day of maximum numbers of cows ashore happens to fall on either side of October 15. Personnel need to be dispersed around the island by October 15 so that all beaches are counted for seals on that day. This has been achieved successfully for the last 15 years. On the day of maximum haul out (around 15th October) the only Elephant seals present are cows, their young pups and adult males. The three classes can be readily distinguished and counted accurately. Lactating pups are not counted, their numbers are provided by the cow count on a 1:1 proportion. The combined count of cows, fully weaned pups and dead pups provides an index of pup production. The count of any group is made until there is agreement between counts to better than +/- 5%. Thus there is always a double count as a minimum; the number of counts can reach double figures when a large group is enumerated. The largest single group on Macquarie Island is that at West Razorback with greater than 1,000 cows; Multiple counts are always required there. RESEARCH ISSUES Much research has been done already to acquire demographic data so that population models can be produced. Thus there will be predicted population sizes for elephant seals on Macquarie Island in 2002 onwards and the annual censuses will allow these predictions to be tested against the actual numbers. The censuses are also a check on the population status of this endangered species. LINKS TO OTHER INDICATORS

A variety of different chemical restraints, or anaesthetics, were trialed on Southern Elephant Seals at Heard Island and Macquarie Island. The trials were performed on female and juvenile seals, in their pre-moult stages. Further information can be found in the papers listed in the reference section below. The chemicals used in this study include: doxapram ketamine xylazine midazolam pethidine thiopentone cyclohexamine based compounds diazepam tiletamine zolazepam 4-aminopyridine Sarmazenil Yohimbine The fields in this dataset are: Anaesthetic Antagonist Dose Mass Time Heart Rate Respiratory Rate Side Effects pH PvO2 PvCO2 HCO3 Total CO2

Twenty three juvenile (8-14 months of age) southern elephant seals (Mirounga leonina L.) from Macquarie Island were tracked during 1993 and 1995. Migratory tracks and ocean areas with concentrated activity, presumed to be foraging grounds, were established from location data gathered by attached geolocation time depth recorders. The seals ranged widely (811-3258 km) and foraging activity centred on oceanographic frontal systems, especially the Antarctic Polar Front and bathymetric features such as the Campbell Plateau region. The seals spent 58.6% of their sea time within managed fishery areas while the remainder was spent on the high seas, an area of unregulated fishing. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.4.1, 88.2 and especially 88.1 were important and distant foraging areas for these juvenile elephant seals. From fisheries records, diet and the foraging ecology studies of the seals there appears to be little, if any, overlap or conflict between the seals and commercial fishing operations within the regulated commercial areas. However, attention is drawn to the possibility of future interactions if Southern Ocean fisheries expand or new ones commence. Furthermore... The dive duration of 16 underyearling (6-12 months old) southern elephant seals Mirounga leonina during their second trip to sea was investigated using geolocating time depth recorders. Underyearling seals had a lesser diving ability, with respect to duration and depth, than adult southern elephant seals. Individual underyearlings dived for average durations of up to 20.3 minutes and depths up to 416m compared to durations and depths of 36.9 minutes and 589m, respectively for adults. Dive duration was positively related to their body mass at departure, indicating that smaller seals were limited to shorter dive durations, perhaps as a result of their lesser aerobic capacity. All seals often exceeded their theoretical aerobic dive limit (average of 22.1 plus/minus 18.1%). The number of dives exceeding the theoretical aerobic dive limit was not related to mass, suggesting that factors other than mass, such as foraging location or prey availability, may have been responsible for the differences in diving effort. Foraging ability, indicated by the ability of the seals to follow vertically moving prey, was positively related to seal mass, indicating that small mass restricted foraging ability. The shorter dive durations of the smaller seals inferred that they had shallower dive depths in which to search for prey, thus restricting foraging ability. Although foraging ability was restricted by size, foraging success was found to be inversely related to mass, the smaller seals gaining a higher proportion of blubber than larger seals during their foraging trips. Thus, despite smaller seals being restricted to shallower depths and shorter durations, their foraging success was not affected. The fields in this dataset are: Area Perimeter ID Latitude Longitude Time Percent CCAMLR EEZ Season Seal Sex Age (months) Days at Sea Range (km) Bearing (degrees) Sea Surface Temperatures (degrees C) Foraging Areas Departure Mass (kg) At sea mass gain (kg) Rate of mass gain (kg) Survival estimates Length (m) Girth (m) Dives Divers per hour Total Time Diving % trip diving Dive Duration Surface Time Theoretical Aerobic Dive Limit Drift