Botulism Outbreak in Waterbirds at Seven-Mile Lagoon in South-East Queensland.

Abstract

Two outbreaks of botulism in waterbirds were investigated at Seven-mile Lagoon in south-east Queensland in June 1978 and April 1981. Both involved many hundreds of birds and coincided with reports of botulism from other localities in south-east Queensland. Deaths of 12 species (six anatids) were recorded, those most severely affected were dabbling ducks. Both outbreaks were associated with a rapid rise in water level after periods of low levels, resulting in the flooding and decomposition of much plant material. Air temperatures were not particularly high (mean maximum: 20.8ÚC for June 1978; 27.5ÚC for April 1981). Botulism may be a more important mortality factor for Australian waterbirds than previously realised.