We analysed growth of the Antarctic bryozoan Melicerita obliqua (Thornely, 1924) by x-ray photography and stable isotope analysis. M. obliqua colonies form one segment per year, thus attaining maximum length of about 200 mm within 50 years. In the Weddell and Lazarev Seas, annual production/biomass ratio of M. obliqua is 0.1 yr-1, which is in the range of other Antarctic benthic invertebrate populations. Production amounts to 3.34 mg C(org) m-2 yr-1 and 90.6 mg ash m-2 yr-1 on the shelf (100 to 600 m water depth), and to 0.13 mg C(org) m-2 yr-1 and 36.8 mg ash m-2 yr-1 on the slope (600 to 1250 m water depth).