Limpus, 2008:

"The introduced fox, Vulpes vulpes, has been the most significant predator of C. caretta eggs in eastern Australia in recent decades. This was one of the reasons that fox predation was listed Nationally as a key threatening process. However, this fox predation of C. caretta eggs has been restricted to the mainland rookeries and there has been no equivalent predation loss on the GBR coral cay rookeries. In addition, fox predation of these eggs has increased from being non-existent or trivial in the mid 1900s through modest but significant predation levels in the 1960s-early 1970s to a major level by the late 1970s (Table 6). In the years that followed there were gradual management changes that resulted in significant reductions in this predation.

The discovery of temperature dependent sex determination for marine turtles (Yntema and Mrosovsky, 1980; Miller and Limpus, 1981) led to a change in emphasis for the conservation of C. caretta in Queensland. During the 1960s – 1970s there was a perception that marine turtle conservation could be achieved via the protection of individual rookeries (Bustard, 1972), rather than through the management of groups of rookeries for the stock as a whole. As a consequence, prior to 1980 in Queensland, the emphasis had been to protect a few island rookeries, which supported about 60% of the C. caretta nesting, as National Parks. This was relatively easy because these island rookeries of the southern Great Barrier Reef had no major predation problems and the land was owned already by the Government.

Because Mon Repos had been chosen as a long term study site for C. caretta, foxes were discouraged from being on the nesting habitat from 1970 onwards. The Mon Repos nesting habitat was at that time almost devoid of trees and shrubs, which made it easy for foxes to be regularly harassed by the research team and local residents. There was some shooting and baiting of the foxes. Fox predation of C. caretta eggs reached a peak intensity (~10% of clutches lost per season) at Mon Repos in the late 1960s. Predation levels declined during the early 1970s and have been relatively trivial since the about 1975 (Table 6).

At Wreck Rock, fox predation of C. caretta clutches continued to increase from the modest level when monitoring commenced in 1968-1969 to 90-95% predation levels in the mid 1970s. This very intense predation rate continued until the mid 1980s (Table 6).

In the early 1980s it was realised that the warm beaches of the mainland C. caretta rookeries were the primary female hatchling producing beaches for eastern Australia (Limpus et al. 1983, 1985). In response, actions were initiated to increase protection to the nesting habitat and to reduce or eliminate predation of turtle eggs by foxes along the mainland beaches of south Queensland. Mon Repos was declared an Environmental Park in 1982 and was later Gazetted as a Conservation Park.

With the introduction of systematic fox baiting on the Wreck Rock and some adjacent beaches in 1987, fox predation of C. caretta eggs has been substantially reduced. It has been at an almost trivial level during most years since the mid 1990s for those years that the baiting project has been maintained (Table 6). Fox control measures have yet to be applied systematically to the approximately 60km of sand beaches that support low density C. caretta nesting between the Woongarra Coast and the Wreck Rock beach, viz: Moore Park, Littlabella, Winfield and Rules Beaches (Table 6) and the other low density rookeries to the north of Wreck Rock beach.

In summary, there have been high levels of fox predation of C. caretta clutches on the female hatchling producing rookeries of south Queensland since the late 1960s until the mid 1980s. Since that time there have been variable but generally low levels of continuing loss of clutches from fox predation. Additional losses of clutches from dingo/dog and varanids on these same beaches have been minor in comparison to the losses from fox predation."

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Citation and/or URL

Limpus, C.J. 2008, A Biological review of Australian marine turtles, i. Loggerhead Turtle, Caretta Caretta (Linnaeus).  Environmental Protection Agency, Brisbane.  

Spatial Coverage

Queensland 

Temporal Coverage

1940s - 2004

Update Frequency

Other Information

None