Peter D. Shaughnessy

VARIATION IN FORAGING AND PARENTAL BEHAVIOR OF KING CORMORANTS

Abstract We studied sexual and individual differences in foraging and parental behavior of King Cormorants (Phalacrocorax albiventer) during the brood-rearing period at Macquarie Island. King Cormorants exhibit sexual dimorphism in size, with males being 16% heavier than females. Females foraged mainly in the morning and males in the afternoon. Five females were shallow divers (1.9 to 6.8 m), and seven females were deep divers (19.6 to 28.0 m); males dived deeper (15.6 to 44.2 m) than both groups of females. The amount of time spent on the bottom (“bottom time”) relative to the dive cycle was higher for shallow-diving females (x̄ = 40 ± SD of 13%) than for males (x̄ = 26 ± 4%) and deep-diving females (x̄ = 27 ± 3%). Total daily dive time and bottom time per day did not differ significantly among groups because shallow-diving females dived more often (x̄ = 211 ± 81 dives per day) than males (x̄ = 68 ± 21) and deep-diving females (x̄ = 70 ± 7). Provisioning rate, trip duration, and proportion of time at sea did not differ significantly for males, deep-diving females, and shallow-diving females. Females, especially shallow divers, compensated for their shallow and short dives with more frequent dives. Consequently, male and female King Cormorants provisioned their chicks at similar rates despite large individual variation in foraging behavior.

Continued population recovery by Australian fur seals

Australian fur seals (Arctocephalus pusillus doriferus) are conspicuous, top-level predators in coastal waters of south-eastern Australia that were over-harvested during the 1800s and have had a delayed recovery. A previous species-wide estimate of live pups in 2002 recorded a near-doubling of annual pup production and a 5% annual growth rate since the 1980s. To determine if pup production increased after 2002, we estimated live pup numbers in 2007. Pups were recorded at 20 locations: 10 previously known colonies, three newly recognised colonies and seven haul-out sites where pups are occasionally born. Two colonies adjacent to the Victorian coast accounted for 51% of live pups estimated: Seal Rocks (5660 pups, 25.9%) and Lady Julia Percy Island (5574 pups, 25.5%). Although some colonies were up and some were down in pup numbers, the 2007 total of 21 882 ± 187 (s.e.) live pups did not differ significantly from a recalculated estimate of 21 545 ± 184 in 2002, suggesting little change to overall population size. However, the colonisation of three new sites between 2002 and 2007 indicates population recovery has continued.

Cranial ontogeny of otariid seals

Abstract Over 2000 otariid skulls were measured for a morphometric study of cranial ontogeny in fur seals and sea lions. Few interspecific differences in cranial ontogeny were observed in the Otariidae, with only minor differences in rates of growth. Sexual dimorphism was significant in all otariids but was more apparent in the larger species. Female otariids of each species showed monophasic development in all characteristics, whereas males expressed monophasic growth for some characters and biphasic growth for others. Biphasic development in skulls of male otariids occurred well after physical maturity had been reached, usually at a suture index of 27. The rate of development varied between skull characters; components relating to the nervous system completed growth well before the rest of the skull, whereas those related to feeding, respiration and vocalisation developed in synchrony with the overall growth of total skull length. Sutures of the calvaria, or braincase, were the first to show partial closure and those uniting the facial bones were usually the last to fuse. As with the calvaria, the orbits and otic capsules developed quickly, suggesting a need for good hearing and vision early in independent postnatal life. Development of the rostral and palatal regions required significantly longer to complete growth.

Status of Australian sea lions, Neophoca cinerea, and New Zealand fur seals, Arctocephalus forsteri, on Eyre Peninsula and the far west coast of South Australia

Two seal species breed on the west coast of South Australia, the Australian sea lion, Neophoca cinerea, and the New Zealand fur seal, Arctocephalus forsteri. Aerial surveys were conducted at intervals of ~3 months between April 1995 and June 1997 to determine the breeding status of sea lions and timing of pupping seasons. Ground surveys between October 1994 and April 2004 aimed at counting sea lions and fur seals, particularly pups. In all, 27 sites were examined. Six new sea lion breeding colonies were documented, at Four Hummocks, Price, North Rocky, Dorothee, West Waldegrave and Nicolas Baudin Islands. All were found or confirmed by ground survey. Pup numbers were equivalent to 12% of the total number of pups estimated in surveys conducted from 1987 to 1992, but primarily in 1990. The sighting of brown pups on aerial surveys of Ward Island, Middle and Western Nuyts Reef supports earlier indications, based on dead pups, that they are breeding colonies. The timing of pupping seasons is not synchronous; estimates are presented for colonies between 1995 and early in 2004, with predictions to the end of 2005. The abundance estimates of sea lion pups highlight the importance of visiting a colony early in the pupping season to determine when pupping begins and ~5 months later when the maximum number of pups is expected. For the New Zealand fur seal, small numbers of pups were recorded at Dorothee, West Waldegrave and Nicolas Baudin Islands, and at Nuyts Reef. These and the previously unknown sea lion breeding colonies on the west coast of South Australia suggest that further colonies may remain to be documented. Because planning for aquaculture ventures is active in South Australia, it is important that the localities and status of sea lion and fur seal colonies be established unequivocally to ensure that the need for Prohibited Area status for islands with breeding colonies and for Marine Protected Areas around them is noted.

Diving pattern and stomach temperatures of foraging King Cormorants at Subantarctic Macquarie Island

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Australian fur seals at Seal Rocks, Victoria: pup abundance by mark-recapture estimation shows continued increase

The abundance of Australian fur seal pups was determined at Seal Rocks, Westernport, Victoria in late December 1997 using a mark–recapture procedure with repeated recapture sessions. Pups (n = 1291) were marked by clipping the black guard hair on the head to reveal lighter underfur. Recaptures from the whole colony were made on eight occasions 1–3 days later. In the recapture sessions, a mean of 32% of sighted pups had been marked. Estimates of pup numbers over the eight recapture sessions were calculated using the Petersen estimate and then combined by taking their arithmetic mean. The combined estimate was 4024 (95% confidence range 3908–4141). In 1991–92, a similar procedure led to an estimate of pup numbers of 2817 (95% confidence range 2703–2930). For both breeding seasons, estimates of pup numbers from each recapture session were also combined assuming a joint hypergeometric distribution; there was little difference in the results from the two procedures, although the confidence intervals for the hypergeometric mean were smaller than those for the arithmetic mean. From 1991–92 to 1997–98, pup numbers increased by 43%, at an exponential rate of 0.059 (95% confidence range 0.0526–0.0664), equivalent to 6.1% per annum (5.4–6.9%). This is greater than the rate of increase of pups at the colony between 1968–69 and 1991–92, which was 0.023 (95% confidence range 0.0198–0.0268), equivalent to 2.4% per annum (2.0–2.7%). Because of the rapid rate of increase of the Australian fur seal colony at Seal Rocks and the importance of the locality for tourism, we recommend that the abundance of pups there be determined every 3–5 years using a mark–recapture technique.

Age and reproductive maturity of New Zealand fur seals (Arctocephalus forsteri) in southern Australia

Abstract New Zealand fur seals (Arctocephalus forsteri) are common in the Australian-New Zealand region, but vital demographic data are lacking. Accurate determination of the age of individuals is critical to the study of age-specific life-history parameters. A cross-sectional sample of female and male New Zealand fur seals was caught and animals were individually marked on Kangaroo Island, South Australia, between 2000 and 2003. Seals were aged through examination of a postcanine tooth, which was removed from each animal. Annual formation of cementum layers was confirmed and accuracy in age estimation was determined by examination of teeth removed from individuals of known age. Indirect methods of assessing reproductive maturity based on characteristics of mammary teats indicated that females 1st gave birth between 4 and 8 years of age, with an average age at reproductive maturity (ARM) of 5 years. No females were observed to breed beyond 22 years. Age of 1st territory tenure in males ranged from 8 to 10 years. Variation in ARM between individuals appears to be related in part to body size and condition. Classification of mammary teat status in combination with techniques for aging live animals provided a means of assessing ARM in the absence of extensive longitudinal data.

Educational and Conservation Value of Whale Watching

Many people support whale watching on the basis that it enhances people’s appreciation and awareness of the whales they are viewing and can lead to the protection of the species and of the environment generally. Because whale watching can directly impact on whales’ behavior it is important that whale watching is beneficial for people’s understanding of whales and for the conservation of whales. This article examines the educational and conservation value of the whale-watching experiences currently offered in New South Wales, Australia. The current education provided lacks structure, there are no clear conservation objectives, and there is limited addition to knowledge and conservation behaviors of whale watchers in the long term. Through improvement of the education provided during whale-watching experiences, it is argued that the whale-watching industry can become a more sustainable form of wildlife tourism and provide conservation benefits for whales and other forms of biodiversity.

Do tour boats affect fur seals at Montague Island, New South Wales?

) and tour boats at Montague Island were investigated between November 1997 and November 1998. The fur seals were in four haul-out sites, which are referred to here as colonies. The study was instigated by the manage-ment requirement of the National Parks and Wildlife Service of New South Wales to determine effects of disturbance from tour boats on the fur seal colonies. At each of 84 inspections, distance between the boat and the colony was measured and seal behavior (or response) was recorded 11 times at 15-second intervals as the boat moved toward the seals. This period of 2.5 minutes was approximately the time tour boats stayed at a colony. Behavior of the fur seals ashore was recorded in four catego-ries of increasing disturbance from “Resting” to “Many moving.” From analyses using multinomial models, the probability of observing a given response by the fur seals and the pattern of the responses as a function of distance from the colony were both infl uenced by the colony under observation. In general, fur seals’ responses were signifi cantly correlated with distance between the study boat and the colony, and with the size of the colony (i.e., number of fur seals visible ashore). In all cases, the probability of the colony remaining in the “Resting” category decreased as the distance between the colony and the study boat decreased. Similarly the probability of the colony showing the maximum response (“Many moving”) increased as the distance decreased. The probability of New Zealand fur seals “Resting” was higher than for Australian fur seals. Tour boats approaching the colonies had a relatively small effect on the fur seals; few or none of them ran to the sea. Based on results from this study, we recommended that the minimum approach distance of tour boats to the fur seal colonies at Montague Island should be 40 m; other recommendations involved how tour boats approach the fur seal colonies. The former has been gazetted as a government regulation and the other recommendations have been incorporated into the license conditions for the tour boats operators.Key words: Fur seals; Tour boats; Wildlife tourism; Wildlife interactions

Subantarctic fur seals Arctocephalus tropicalis at Heard Island

Both the Antarctic fur seal Arctocephalus gazella and the Subantarctic fur seal A. tropicalis breed in the Southern Ocean (Fig. 1). The former species breeds on islands south of the Antarctic Convergence and immediately north of it, the latter on islands north of the Convergence (Bonner 1981). To date, sympatric breeding of the two species has been reported from three localities north of the Antarctic Convergence; Prince Edward Islands, Iles