Sea perch are widely distributed around most of New Zealand, but are rare on the Campbell Plateau. They inhabit waters ranging from the shoreline to depths of 1200m, but are most common between 150 and 500m. Until recently, it was believed that there were two species of sea perch, H. percoides and H. barathri in New Zealand waters. However, recent genetics research has determined that there is probably only one species of sea perch in New Zealand waters, H. percoides (Smith, 1998). Because of this confusion, there is limited information on sea perch biology. Trawl surveys from about 1990 show sea perch size to vary with depth and locality without an obvious pattern, possibly representing population differences as well as life history characteristics.
Sea perch are viviparous, extruding small larvae in floating jelly masses during an extended spawning season. Sex ratios observed in trawl survey samples show about 5 males for every 4 females.
Sea perch are opportunistic feeders and prey on a variety of animals, on or close to the seafloor.
Growth is relatively slow throughout life. After about age 5 years, males appear to grow faster than females (there is some uncertainty due to small sample sizes). Males mature at 19 to 25cm, about 5-7 years, whereas females mature at between 15 and 20cm, around 5 years (Paul & Francis, 2002). While not objectively proven it is thought that these fish live for about 40 years in the east coast South Island and Chatham Rise area. Maximum size for sea perch is about 56cm.