Ask Dr Dazza | Moreton Bay Bugs

Published 1:38pm 15 December 2021

ANOTHER of our favourite festive seafoods are bugs. Not the flying kind, but rather the Moreton Bay bug and the Balmain bug.

These animals are more commonly called slipper lobsters in other parts of the world. The Balmain bug tends to be broader and flatter than the Moreton Bay bug. Balmain bugs extend from about Bundaberg south to the NSW/Victoria border, while Moreton Bay bugs are abundant in offshore waters along the entire Queensland coast.

There are two species of Moreton Bay bug that are sold together – the “mud bug” and the “reef bug”. There is also more than one species of Balmain bug. Mud bugs are generally more abundant in waters between 10 and 30m deep while reef bugs are generally more abundant in depths between 40 and 50m.

Moreton Bay bugs are relatively short-lived, quick-growing and quick-maturing. The lifespan is up to four years for the mud bug and eight years for the reef bug. They mature after about one or two years. Females usually spawn twice during the summer, with about three months between spawning events.

After hatching, bugs have a type of larvae called a phyllosoma larvae and these larvae typically associate with jellyfish. They are thought to possibly use jellyfish for food, transport and protection.

Bugs are generally active at night, which is when they feed, and mostly stay buried in the sediment during the day. Burying is their main method of avoiding predators. They feed on a range of other seabed invertebrates including mollusc such as saucer scallops.

Unfortunately, Moreton Bay bugs are rarely encountered by anglers. The only effective way of catching them is through trawling. They do not readily enter any baited traps or pots. Despite their name, while they are caught in Moreton Bay, it is not an important production location for them. The waters off Townsville and Gladstone are two of the more important areas for their capture.

Given their high value for well over a decade, there has been substantial interest in farming them but farmed supply remains limited.