Rearing trials of Halla parthenopeia under laboratory conditions (Polychaeta: Oenonidae)

Abstract

Abstract A small scale attempt to maintain and rear the worm Halla parthenopeia in laboratory conditions was conducted. Five bivalve species ( Paphia undulata , Cerastoderma glaucum , Venerupis pullastra , Ruditapes decussata , and Gafrarium pectinatum ) were used to investigate preferred food item, feeding rate and growth of the worm. H alla parthenopeia are capable of using different types of clams, although they grew better with Paphia undulata and C. glaucum as food items. The highest average daily predation rates in case of P. undulata as a prey were 1.73, 2.13 and 2.57 individuals per predator per day for small, medium and large groups of H. parthenopeia , respectively. The daily predation rate on C. glaucum was low with an average: 0.50, 0.63 and 0.73 individuals per predator per day for the small, medium and large worm groups, respectively. The daily growth rate of H. parthenopiea increased when it was fed P. undulata (average: 0.083, 0.071 and 0.038 g/day for small, medium and large worm groups respectively), compared to an average of 0.044, 0.034 and 0.020 g/day for small, medium and large worm groups, respectively, when worms were fed with C. glaucum . The biochemical composition of three different sizes of the worm was also determined. Protein was the highest biochemical constituent with an average of 51% of the dry weight, followed by lipids with an average of 25.88% of the dry weight; meanwhile carbohydrate was present at an average of 20.72%. Our findings indicate that growth of H. parthenopeia can be improved when fed with a suitable prey item and suggest that it is feasible to successfully culture this protein-rich worm in captivity.