Performance of Eunicid Polychaetes Commonly Exploited by Artisanal Fishers Under Different Culture and Diet Regimes Between 2015 and 2017 (Marphysa Mossambica)
Abstract:
Eunicid polychaetes are harvested and exploited as fishing bait in various regions around the world [1]. Unregulated harvesting into the intertidal flats of Southeast Queensland, Australia has destroyed the habitat for many biodiversity and loss of the polychaete [2]. Culture of the worm could provide an alternative supply of polychaetes as baits for f ishing and also as feeds in mariculture. Thus reduce time spent during digging for the bait worms, and pressure on use of Rastronobela argentia and sardine which are used as human food. Therefore, this study aimed at investigat ing the performance of cultured Eunicid polychaete under different regimes. Several species of Eunicid worms have been successfully cultured in laboratory settings for research, aquaculture and bait recreational fishing. This study cultured polychaetes in 2 culture set up regimes (semi intensive cages in situ, and aerated and recirculation lab inten sive cage) on known stocking densities. The diet regime comprised of spinach, manure and a mixture of both manure and spinach diets on known quantities. The performance was monitored on growth rate, survival rate, reproduction, and burrowing behavior. The results obtained indicated mean survival rates were highest in the semi intensive cage at 75.31% compared to the aerated and recirculation system at 45.11%. Similarly the highest mean growth rates recorded was in the semi intensive cage in situ at 0.057- 0.102 mm/day against the aerated and recirculation lab intensive cages at 0.015 – 0.021 mm/day. On the other hand in the diet regime where spinach was used as a control. The survival and growth rate was highest on the cow dung manure diet followed by spinach diet and lowest in the 1:1 mixture of manure and spinach. It can be concluded that, the semi intensive cage in situ and cow dung manure diet could offer the best culture technique that can be adopted for the artificial rearing of the Eunicid polychaete. This can be compared to the survival rate obtained for the Marphysa sanguinea spp recorded of up to 90% (e.g., Xu et al., 2015) and a mean growth rate of 0.19-0.25 mm/day Xu et al. (2015) grown under laboratory conditions. Another study by Naylor et al. (2011) reported growth rates of 0.16-0.44 mm/day for Marphysa sanguinea collected from estuarine mudflats in the UK.
