An experimental study of the use of arm regeneration in estimating rates of sublethal injury on brittle-stars

Abstract

The ophiuroids Ophiomyxa flaccida (Say), Ophionereis reticulata (Say), Ophiocoma wendtii Müller & Troschel, O. echinata (Lamarck), O. pumila Lütken, Ophioderma appressum (Say), O. cinereum Müller & Troschel, and Ophiolepis impressa (Lütken) in back-reef populations in Jamaica were found to differ significantly in the number of arms regenerating. The proportion of arms regenerating varied from 74.4% for Ophionereis reticulata to 28.3% for Ophiolepis impressa. Regeneration rates, hitherto unknown except for Ophiocoma pumila, were determined for all the species for a single arm over a 3-month period. O. wendtii had the highest rate, regenerating 55% of its mean maximum arm length in 3 months, and O. impressa the slowest, regenerating only 23% of its mean maximum arm length in the same time. Injury rates, i.e., the number of arms broken and the total percent loss estimated to have occurred in the month prior to collection, were determined by dating wounds with reference to regeneration rates over 1 month. The species differed significantly in injury rates. O. pumila and O. reticulata suffered the highest levels of injury and O. impressa the least. Injury rates were not simply related to either the palatability to predators or the behaviour of the brittle-stars.