Effect of abiotic factors on culture of Hypnea cornuta (Rhodophyta) in Fiji under a climate change perspective

The impacts of global climate change and anthropogenic activities have resulted in warmer oceans, sea level rise and changes in oceanic chemistry. These changes in the marine environment is affecting the sustainability of... [ view full abstract ]

The impacts of global climate change and anthropogenic activities have resulted in warmer oceans, sea level rise and changes in oceanic chemistry. These changes in the marine environment is affecting the sustainability of marine species for instance aquatic plants and animals and conserving these species is becoming a major concern. One of such species is Hypnea cornuta which is native to Fiji. H. cornuta is widely used by coastal communities as a source of food and for income generation but abundance and availability of it is becoming an issue. Hence, this study investigates the effects of temperature, salinity and nutrient concentration on the growth of H. cornuta. In this study an orthogonal experimental design was used for the aquaculture of H. cornuta at different temperatures (24°C and 30°C), salinity (25 ppt and 40 ppt) and nutrient concentrations (0.1 mg/l and 0.5 mg/l nitrogen). It was found that H. cornuta showed negative specific growth rate across all the culture treatments. The highest biomass loss was observed in high temperature than low temperature treatments and high salinity than low salinity treatments. Nutrient concentrations showed limited effects. Therefore, an increase in ocean temperature and salinity (the consequences of climate change) will further affect the abundance and availability of H. cornuta in Fiji as it was not able to grow well in culture conditions. The coastal communities will face the issue of food insecurity and income generating problem hence it is really important to conserve this species from an inevitable impacts of climate change.