Cirolana harfordi

Cirolana harfordi has an oval, dorsoventrally compressed body, and a pair of antennae, which it uses for finding food and mates.^[4] Its body is generally white with fine brown spots, and it can reach up to 2 cm in length.^[5]

Cirolana harfordi can be described as both a scavenger and a predator, feeding on crustaceans and polychaetes, particularly Syllis fasciata.^[6] The food from one meal can fill the isopod's elastic digestive system and can nutritionally sustain this organism for three weeks.^[6]

Female Cirolana harfordi will give birth one or two times during their two-year lifespan.^[5] Like all members of the superorder Peracarida, they lay their eggs directly into a special pouch called the marsupium, located between the 3rd and 6th walking legs.^[7] The young are brooded here for 3 to 4 months while they undergo several molts, after which they emerge as mancae, or juveniles that closely resemble the adult form.^[2][6] Each brood contains 18 to 68 young.^[6]

When Cirolana harfordi group into large aggregations, they can become a concern for humans and fisheries.^[5] The isopods can attack living fish, especially those cultured in nets or caught in traps, and kill them.^[8] There is also at least one report of a C. harfordi swarm biting and hospitalizing a teenager in Melbourne, Australia.^[9] The species does not usually reach aggregation densities great enough to pose a concern, but in Australia, C. harfordi is an invasive species and lacks natural predators to limit its population growth.^[5]