Mussel Beard

Amphisbetia bispinosa

Amphisbetia bispinosa, commonly known as the Mussel beard, is a species belonging to the family Sertulariidae. This hydroid can be identified by its colonial structure, which consists of upright, branching stems that can resemble a beard. It typically inhabits benthic environments in the temperate waters of the Southwest Pacific, particularly around New Zealand. The Mussel beard is often found at various depths, with a significant number of recorded occurrences at depths shallower than 40 meters, and most found below 120 meters. This species feeds primarily through filter feeding, capturing plankton and other small particles from the water. Reproduction occurs through a complex life cycle where the zygote develops into a planula, then into a polyp, and later into a free-swimming medusa stage. This life cycle allows for a wide dispersal of the species, contributing to its presence across multiple dive sites. Encounters with the Mussel beard during dives can be intriguing, as divers may observe its unique colonial formations clinging to substrates in the underwater landscape. While the species has not been evaluated for conservation status by the IUCN, it is essential for divers to be mindful of their impact on such delicate ecosystems.