Possum control

​Possum control

​Possums are a pest in New Zealand. They eat the native trees, birds and invertebrates, and destroy ecosystems.

They can also spread tuberculosis, which has a huge financial impact on the dairy and beef industries.

Methods of possum control​

Possums are currently controlled through trapping and poisoning (using mainly 1080). These methods are very costly and in the case of poisoning, not specific to possums.

​What is biological control?

Biological control, or biocontrol, is the use of a living organism, or the product of a living organism, to control the numbers of another organism, usually a pest.

​Methods of biocontrol

Scientists in New Zealand explored several biocontrol methods for reducing possum numbers. These included using toxins or vaccines against possum fertility.

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How do the vaccines work?

The vaccines act as a contraceptive. They make a possum’s immune system produce antibodies against its own reproductive proteins. The antibodies then destroy the proteins, so the reproductive system stops working and the possum cannot have any young.

​Are all possums affected?

The main target of the contraceptive vaccines is female possums, however some vaccines may also affect males. The reason females are targeted is because even if 90% of males were made infertile, the remaining 10% could still breed and maintain the same population level.

​Advantages of reducing possum fertility with a vaccine

• ​Vaccines are effective. In a trial vaccinating possums against the reproductive protein,70% of possums were infertile two years after receiving the vaccine

• Vaccines are humane. Contraceptive vaccines do not cause the possums’ pain or distress. The possums are perfectly healthy and live a normal lifespan.

• Vaccines do not affect other animals. The risk to non-target species is minimal because efforts are made to make the vaccines as specific as possible for possums.

• Vaccines are environmentally friendly. Vaccines are not toxic and will not pollute the environment.

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Disadvantages of reducing possum fertility with a vaccine

• Currently, vaccines only last for a few years at best. After initial vaccination, the antibodies in the possums’ bodies will gradually decrease. After two to three years, the possums will need to be vaccinated again, which will cost money.

• Vaccines are expensive and time-consuming to develop. However, any new possum control method would be expensive and time-consuming to develop.

• A genetically modified organism may be used as a carrier to take the vaccines to the possums. This may be unacceptable to some people.

Multiple Choice

Possums are common ______ in New Zealand

• pests

• pets

Multiple Choice

True or False? Possums are New Zealand native mammals.

• True

• False

Multiple Choice

True or False? Possums are found only in dense forests.

• True

• False

Multiple Choice

True or False? Possums eat and destroy our native trees.

• True

• False

Multiple Choice

Possums were introduced to NZ from Australia mainly for:

• their fur

• their meat

• their cuteness

• keeping as pets

Multiple Choice

The Department of Conservation (DOC) use 1080 to control possums. 1080 is a:

• vitamin

• poison

• food

• predator

Multiple Choice

Possums can be controlled by introducing another predator that can eat possums. This is called:

• Biocontrol

• Chemical control

• poison baits

Multiple Choice

Some people are against using poison baits to control possums because:

• Poison cannot kill all possums

• Poison can kill other animals as well.

• It is hard to make poi

Multiple Choice

Scientists in NZ develop a contraceptive vaccine to control possums. This is a:

• Biocontrol method

• Chemical control method.

• slow acting poison.

Multiple Choice

The contraceptive vaccines mainly affect the:

• Male possums

• Female possums.

Multiple Choice

The contraceptive vaccine makes the possums:

• more reproductive

• Less reproductive

• weaker and sick.

• healthier and stron

Multiple Choice

What method of possum control is more humane?

• Using 1080 poison

• Using contraceptive vaccines.

• Shooting at night

• Using traps

Open Ended

Discuss the advantages (good things) of using bio control methods like vaccine to control the possum numbers in NZ.

Open Ended

Discuss the disadvantages (bad things) of using vaccines to control the possum numbers in NZ.