Research undertaken by the New Zealand Sea Lion Trust began in 1995 as part of an MSc thesis.
At present it involves monthly surveys of areas regularly frequented by several sea lions in an effort to cover most of the mainland population. Photographic identification of natural scars allows us to recognise many of the sea lions on the beaches which can then be studied over several years.
New...! Summary of NZ Sea Lion research undertaken on
mainland New Zealand, including updated publication list
[ 63 page MS Word document ]
Excerpts from our April 2005 Newsletter.
Impact of tourists (Jenna-Lyn Zaino and Joanna Ory)
Student projects conducted at the end of 2004 found sea lions to be very tolerant of people and the greatest effect came from more extreme human actions such as clapping or throwing things at the sea lions, causing them to wake up and aggressively roar at people. Sea lion behaviours were also found to change with time of day, weather conditions and the presence of other sea lions. Sea lions were found to be least active during the middle of the day which is unfortunately when most people go to see them. It is therefore most important to prevent people deliberately disturbing sea lions in order to get photos, when they are resting.
Bleaching sea lions (Shannon Williams)
The main focus of this study was to document the annual breeding migration of adult male sea lions, resident in Otago, to the Auckland Island breeding colonies - a distance of approximately 600 km. This involved bleach marking letters and numbers into the hair of adult male sea lions which allowed a DoC team led by Dr Louise Chilvers to record the presence and breeding behaviour of these males in the Auckland Island colonies. Of the 34 adult males bleached, 21 were positively identified in the Auckland Islands and 5 of these were observed holding breeding territories. The quickest recorded migration was 4 days! Photos showed a dramatic degree of weight loss, and often multiple scars from fighting, in many of the migratory males. My study has revealed a high rate of migration by adult males from Otago to the Auckland Islands in the breeding season. These sea lions are involved in breeding and thus provide genetic input to the population as a whole. The study has also reinforced how easily disease could be spread throughout the entire population.
Breeding behaviour (Jojo Jackson)
This study focused on the breeding behaviour of New Zealand sea lions at Otago Peninsula. Timing and location of births were recorded as accurately as possible for the 2003/04 and 2004/05 breeding seasons. Birth dates at Otago were similar to peak pupping dates at the main breeding colonies. Foraging cycles and attendance patterns of mothers were determined through 10 consecutive days of observation each month from March-June. Otago females were found to have, on average, shorter duration cycles than females at the Auckland Island breeding colonies. This may suggest a better foraging environment at Otago. In an effort to understand the dynamics involved in the formation of breeding colonies, interactions between females ashore were recorded to investigate the gregarious behaviour of New Zealand sea lions. At the Auckland Islands females gather for pupping and then disperse, compared with Otago where they disperse prior to pupping and converge later.
If you would like to join the trust and receive a copy of our newsletter 3 times a year, go to our Sea lions and you page to see how.
If you would like to report a sighting of a tagged or branded sea lion please go to the Sea lions and you page. Photos showing the shape, colour and number of the tag or the number of the brand would be useful.
New Zealand Sea Lion Trust
19 Irvine Road, The Cove,
Dunedin, New Zealand
Email: sealiontrust@clear.net.nz
