Effects of Rearing Density on Growth of the Polychaete Rockworm Marphysa sanguinea

Abstract

Effects of rearing density on growth and survival of the polychaete rockworm Marphysa sanguinea have been investigated in order to develop rearing techniques for this species. This study was examined over a nine-month period in the Fisheries Science and Technology Center of Pukyong National University. Three rockworm densities, 500, 1,000 and 2,000 worms•m -2 with weight ranges of < 0.5 g, 0.6-1.5 g, and 1.6-2.5 g, and the no feed control treatment, were stocked in triplicate 0.10 m 2 boxes with sand bottoms. Growth rates were checked with 15 randomly sampled rockworms from each box at months 3, 6 and 9. Results showed that SGRs in all treatments were higher during the first period (0-3 months) than the second (3-6 months) and third periods (6-9 months) for all treatment densities, while SGRs decreased with increasing density. However, survival and growth of worms at high density was not better than low density, but daily biomass production in medium and high density groups was 6.28 g m -2 day -1 for the rockworms of 0.6-1.5 g with 2,000 inds•m -2 , and 12.6 g m -2 day -1 for group between 1.6-2.5 g with 2,000 inds•m -2, and 14.7 g m -2 day -1 for the group of individuals <0.5 g with 1,000 inds•m -2 . Results showed that M. sanguinea can be one of the most suitable species to commercially exploit in a farming system. In particular, specified densities permit elevated pure production.

Guess who? On the importance of using appropriate name: case study of Marphysa sanguinea (Montagu, 1813)

“…From the literature, we identified works on development regarding sex gonad (Yu et al 2005, specimens from Shandong Province, China), reproduction cycle (Yu et al 2005; Ouassas et al 2015, specimens from Saharan area, Morocco), metabolism and excretion (Yang et al 2015, specimens from Dalian, China). Several papers also study rearing of so-called M.sanguinea with effects of density on growth (Parandavar et al 2015, specimens from South Korea) or appropriate feeding for early juvenile stages (Kim et al 2017, specimens from South Korea). Besides Li et al (2016), several papers focus on genetic elements of this species, such as purification, characterisation and cDNA cloning of opine dehydrogenases (Endo et al 2007, specimens from fishing shops, Japan) or genetic diversity from different geographical populations (Zhao et al 2016, specimens from China).…”

Survival, growth and biomass of mud polychaete Marphysa iloiloensis (Annelida: Eunicidae) under different culture techniques

“…Polychaetes with FS in their diets (BF + FSS and FSS) attained significantly higher body weights than those in pure BF diets (BFS and BF + BFS). FS contained high level of protein (51%) which is closer to the protein contents of commercial fish food pellets 54%and shrimp feed (52%) used in feeding M. sanguinea (Kim et al, 2017;Parandavar et al, 2015). Moreover, commercial fish meals (protein-rich source) were fed daily (Santos et al, 2016) or three times per week ad libitum (Nesto, Simonini, Prevedelli, & Da Ros, 2012) with 20,000 culture units producing 1.2-1.5 tons/month supplying shrimp hatcheries in Thailand (Panakorn, 2015).…”

“…In the study of ThiThu et al (2019), adult M. sanguinea with an initial body weight of 2.005 ± 0.001 g had 60% survival after the 3-month culture period. Another study byParandavar et al (2015) showed that M. sanguinea with an initial weight of 0.44 ± 0.04 g had higher survival rate of 78 ± 4% at the end of the 9-month culture. Obviously, studies that initially used adult or large size polychaetes would yield a higher survival rate at the end of the culture period compared to those that initially used larval stage polychaetes.…”

Insight into aquaculture's potential of marine annelid worms and ecological concerns: a review

“…Salinities close to 15 or 40 psu seemed to be the lower and upper physiological limits, respectively, for this species. Parandavar et al (2015) evaluated three different densities of rockworm (500, 1000 and 2000 ind m À2 ) and showed that the M. sanguinea specific growth rates decreased with increasing densities. Nevertheless, daily biomass production in different density groups can vary between 6.28 g m À2 day À1 and 14.7 g m À2 day À1 , suggesting that this can be one of the most suitable species to be commercially exploited in a farming system.…”