Frequently Asked Questions
What is a swim bladder?
A Spiny Pufferfish swim bladder found by P. Merrick on Avoca Beach, New South Wales, January 2005. Photo © P. Merrick. View larger image.
The images show a strange balloon-like object found by P. Merrick on Avoca Beach in January 2005. The object is the swim bladder from a Spiny Pufferfish (often called Porcupinefishes or Burrfishes).
The swim bladder is a flexible-walled, gas-filled sac located in the dorsal portion of body cavity. It controls the fish's buoyancy and in some species is important for hearing. Most of the swim bladder is not permeable to gases, because it is poorly vascularised (has few blood vessels) and is lined with sheets of guanine crystals.
Spiny Pufferfish swim bladders are not commonly encountered. Only a few examples of Spiny Pufferfish swim bladders have been brought to the Australian Museum for identification during the last twenty years.
Related links
- How often can Spiny Pufferfishes inflate?
- More information on how the swim bladder works
- View the Blue Mackerel dissection swim bladder page
- View the Spiny Pufferfishes list
Further reading
- Scott, T.D., Glover, C.J.M. & R.V. Southcott.1980. The marine and freshwater fishes of South Australia. Government Printer, Adelaide. Pp. 392.
