Contraceptive treatment on wild Monkeys in Hong Kong

[Guest guest]

Dear members,

 

For those interested in humane methods to reduce monkey populations, here

is some info about the contraceptive treatment of wild monkeys in Hong

Kong, kindly provided by Mr C.L. Wong, Agriculture, Fisheries and

Conservation Department, Hong Kong Government. The results seem

encouraging. Although the catching part is hard, birth control appears to

be an effective method to control monkey populations and to reduce

human-wildlife conflict, especially in large Asian cities.

 

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From Mr C.L. Wong, Hong Kong Government:

 

We introduced the 1st phase of the contraception programme to wild

monkeys in early 2002 as a field trial where 20 female monkeys were

captured and treated with SpayVac. The main purposes are to check the

effectiveness of the contraceptive vaccine and to monitor the behaviour and

sociobiology of the treated macaques. A monitoring programme was started

immediately after the contraceptive treatment on macaques in the field. In

addition to the 20 females treated with contraceptive vaccine, some male

macaques were also captured and treated with chemical vasectomy (blocking

of the vas deferens by chemical).

 

Without the agreement of the contraceptive vaccine supplier, I am

not able to provide you a detail account on the results of the programme as

we have signed a contract with the supplier, the ImmunoVaccine Technologies

Inc. Canada. However I could provide you a very brief summary of our

results after the 1st year monitoring:

 

a. Ten treated female monkeys and four treated male monkeys were

seen again in field visits.

b. None of the treated female monkeys were seen pregnant in the

birth season.

c. Normal sexual characteristics (e.g. swelling and reddening of the

genitalia in mating season) of the treated monkeys were observed.

d. Mating activities for both treated male and female monkeys were

observed to be normal as compared to other monkeys.

e. No obvious change of social status of the treated male monkeys in

its group was detected.

f. Coherency of treated monkeys to other monkeys in its group was

still high and group splitting/dropouts of treated monkeys was not observed.

 

 

With the encouraging results from the first phase, we decided to

extend the field trial to the 2nd phase in late 2003. The aim of the

extended field trial of contraceptive treatment on wild monkeys is to treat

about 30 - 55% fertile female monkeys in the target groups so that

effective data in population dynamics of the monkey groups can be obtained

for developing of a long-term plan on population control of wild monkeys.

We planned to focus this field trial to 3 groups of wild monkeys of about

330 individuals.

 

The problem we have now is to catch the monkeys. They are so

clever that they are likely to avoid traps after some of their companions

got trapped. That is why we are only about half-way done for the time

being. The situation in Hong Kong also cannot allow us to use some

effective traps as built-up/ residential areas surround the so call " Monkey

Hill " .