Over-abundance of koalas at Cape Otway created a unique management situation, as over-browsing of their favourite food sources can lead to the death of those trees. This tree loss leads to insufficient food and as a consequence a decline in the health of the koala population.
The increase in koala numbers are also affected by the favourable climate, an absence of predators and a reluctance to leave the preferred food source of Manna gums. When koala populations become unsustainably high and their food source is damaged by over browsing, the result is often starvation and death.
Since 2015, DELWP has been working to manage the over-abundance of koalas to achieve a healthy habitat and a population of healthy koalas at Cape Otway.
The Cape Otway Koala Management Actions
In early 2015, DELWP established an independent panel of animal welfare and ecological experts on how to proactively manage the koala over-abundance at Cape Otway. This resulted in the development of the Cape Otway Koala Management Actions. The intent of this document is to improve the health of the Cape Otway koala population and their habitat.
Key management actions include health assessments, translocation, euthanizing any unhealthy koalas to prevent their suffering and fertility controlling healthy females.
One of the complementary actions is to enable orphaned back young koalas from Cape Otway to be rehomed into suitable wildlife parks and zoos.
What programs have been delivered at Cape Otway?
The 2016 Spring Koala Management Program
Cape Otway Koala timeline
Koala management programs summary
The first recommended action by the expert panel was to conduct a four day koala health assessment in May 2015. Results indicated a link between poor canopy cover and poor koala health.
A two-week operation to improve the welfare of koalas at Cape Otway involved capturing and assessing a total of 395 koalas.
A total of 341 healthy koalas were released back into the wild, 166 females were treated with fertility control hormone implants, and 37 koalas were radio-collared and translocated to an area in the Great Otway National Park as part of a trial. Unfortunately, 54 koalas were humanely euthanased due to health issues.
During the operation, 69 dependent back young were captured and released with their mothers. Four back young were rehomed to a Victorian wildlife park after their mothers were euthanased due to poor health.
Initial monitoring (30 days) of the trial translocation by Arthur Rylah Institute (ARI) showed positive results with the majority of koalas showing early signs of adapting to their new environment.
Our scientists with expertise in wildlife ecology and habitat modelling used habitat mapping to identify a suitable translocation site north of Lorne.
As part of the habitat mapping process, areas where planned burns were scheduled and areas close to main roads were excluded. Site visits were undertaken to estimate resident koala densities and verify the presence of koala food trees prior to finalisation of the translocation site.
This map highlights areas of modelled koala eucalyptus habitat.
Translocation of koalas from Cape Otway to the Great Otway National Park was undertaken to help manage the immediate welfare needs of the Cape Otway koalas and reduce over-browsing of their preferred habitat. Translocating koalas at this time of year enabled them to adapt to their new environment before any cold, wet weather.
Over four weeks, a total of 528 adult koalas and 119 dependent back young were captured and health checked by qualified vets. Some 213 females were fertility controlled, with 69 adult koalas and one dependent back young euthanased due to health related issues and to prevent further suffering. Twelve dependent back young were re-homed at approved wildlife parks and 85 koalas not suitable for translocation were released back at their site of capture at Cape Otway.
Monitoring the trial translocation koalas
Most koalas in the trial and in the control group at Cape Otway, were recaptured and assessed through the second comprehensive monitoring conducted by ARI in February 2016. The results were encouraging with the translocated animals doing better than those returned to their original home ranges at Cape Otway.
A two week fertility control and health check program focused on catching female koalas not previously caught on private properties with high koala densities.
A total of 259 koalas were captured and assessed at the vet station. Of those, 246 were female and 13 male, with 184 healthy females fertility controlled.
Unfortunately vets considered 10 koalas to be in poor health and these were humanely euthanased to prevent further suffering.
A total of 249 healthy koalas were released back to their site of capture at Cape Otway. No dependent back-young were encountered.
Results indicated an overall improvement in the health of the koala population with such a low percentage (4%) of koalas euthanased, significantly down from previous actions.
The Spring program to conduct fertility control, health check and translocation of koalas aimed to reduce koala population at areas of high densities and declining canopy cover to assist the Manna Gum woodland to recover.
A total of 344 koalas were captured and assessed. Of those checked, 100 healthy females were fertility controlled and 236 koalas were translocated to suitable habitat in the Great Otway National Park. All captured animals were in good condition. There were 29 koalas which our veterinarian determined to have significant health issues and genetic abnormalities. These animals were humanely euthanased to prevent further suffering. There were no orphaned back young during the delivery of the program.
All efforts were made to ensure female koalas were not translocated if they were pregnant, or carrying female pouch or back young under two kilograms. All translocated females and female back young over two kilograms were fertility controlled prior to translocation.
What further programs are planned for Cape Otway?
The koala management program at Cape Otway is informed by the results of the previous programs and relevant targeted research.
ARI have finalised a report on the carrying capacity and habitat health assessment of Manna Gum dominated areas of the region. This will assist the BSW region to plan koala management programs at Cape Otway and other forest areas in south west Victoria into the future.
Results from recent koala density surveys confirmed that further programs, as detailed in the Management Actions, need to be taken to manage the koala population at Cape Otway.