By JONATHON HOWARD
CANE TOAD BREEDING
They breed in still or slow-flowing water often tangling the spawn around rocks or water plants. The appearance of cane toad spawn is unique in Australia and consists of long gelatinous strings with double rows of black eggs. Females lay 8,000 to 35,000 eggs at a time and usually breed twice a year and the eggs hatch in 48-72 hours into tadpoles. They develop into toad-lets in between 17 days to six months. Cane toads need between six and 18 months to reach sexual maturity and have a lifespan of about five years.
ENVIRONMENTAL IMPACTS
According to the CSIRO cane toads are not officially recognised as a threatening process in Australia, because not all states consider toads to be a problem. Only animals that are of national significance are officially recognised as pests. Although no extensive environmental monitoring studies have been undertaken, there is evidence of the environmental impacts of cane toads. A decline in quoll numbers and native frogs in areas where large numbers of cane toads are found has been recorded. Cane toads eat mainly insects, but will eat any small creature that fits in their mouth. They also eat honey bees and are likely to compete for food with native animals. In addition they may carry diseases that could be transmitted to native frogs and fishes.
CURRENT CONTROL ACTIVITIES
There is currently no effective control method that can be applied to the vast area where cane toads have spread. In some areas, bounty systems have been established with community involvement. Such systems carry with them the danger of incorrect identification; at times two-thirds of animals brought in turn out to be harmless native frogs. CSIRO scientists are working with gene technology to find a biological control method. Scientists at the University of Adelaide are trying to find a sex pheromone in cane toads that may be used to disrupt their breeding cycle.
Source: CSIRO
