St Helena Island: The 1986 decision that left a Moreton Bay island teeming with deformed wallabies

Wildlife rangers are in midst of a mass-execution of hundreds of wallabies riddled with diseases like Q fever, Barham Forest and Ross River viruses on an island that was once a maximum-security prison.

Wildlife officers are nearing the end of a mass-execution of hundreds of wallabies on a Queensland island, where more than 1000 animals will soon be culled.

National Park rangers have already destroyed hundreds of wallabies marked as pests on St Helena Island in Moreton Bay, using high-powered rifles and precision night-vision scope equipment.

The Courier-Mail was told the out of control population, which had surged to plague-proportions in recent years, was attributed to a decision from the Queensland Parks and Wildlife Service (QPWS) to release six red-necked wallabies to the island in 1986.

But with no natural predators in sight, the tiny protected population soared to teem the island with more than 1000 inbred creatures, riddled with diseases and featuring gross deformities.

Rangers have already killed hundreds of red-necked wallabies on the island. Picture: Greg Miller

A spokeswoman from the Department of Environment, Science and Innovation (DESI) said a 2017 report revealed significant health problems among the population, including blindness and other irregularities.

“Red-necked wallabies are also known hosts of diseases such as Q fever, Barham Forest and Ross River virus,” the spokeswoman said.

“Due to the number of annual visitors to the island each year, the potential transfer of disease was an unacceptable risk.”

Historical photo of former colonial prison St Helena Island, in Moreton Bay. Picture: John Oxley Library

In 2019, rangers began terminating the population on St Helena Island, wiping out hundreds of the wallabies as part of the “pest management strategy” and burying them in large pits.

But about 200 remain under surveillance, with QPWS considering the use of thermal drones to accurately count numbers before launching a final assault to totally cleanse the island of the creatures.

A department spokeswoman said the public will be restricted from the area when the remaining wallabies are killed as a safety precaution, with the use of thermal imaging for the night-time operations.

St Helena Island was at one time Queensland's foremost maximum security prison and part of Brisbane's 'Ghost Trail'. Picture: Tourism Queensland.

“The wallabies are not considered native to St Helena Island, which is a key RAMSAR site for migratory sea birds,” the department said.

“As the population expanded, they damaged the island’s natural and cultural values by eating native vegetation and killing trees, and caused erosion of stone walls at their footings by trampling and licking salt from the stone.

“Tour operators provided advice that the population was impacting on visitors.”

The QPWS management program is crucial for protecting natural and cultural elements on the Moreton Bay Island, the department said.

Cells in colonial prison on St Helena Island. John Oxley Library

“The wallabies were humanely euthanised by experienced rangers trained and accredited in the use of firearms, and buried on the island,” the spokeswoman said.

“The control program was conducted following consultation with the Quandamooka Yoolooburrabee Aboriginal Corporation, and the RSPCA.”

According to St Helena Island’s website, it served as a high-security colonial prison from 1867 due to overcrowding in Brisbane’s jails.