Preliminary study of the effect of nutrient enrichment, released by marine floating cages, on the coral disease outbreak in Karimunjawa, Indonesia

Abstract

Coral disease is a significant factor causing the degradation of Karimunjawa coral reefs. The objective of this study was to determine the possible effects of nutrient enrichment, released by floating cages used for fish culture, on the coral disease outbreak in Karimunjawa National Park, Java Sea. The islands of Genting, Sambangan, and Seruni were selected as study sites as they represent islands with human habitation and a high intensity of mariculture activity, no human habitation and a high intensity of mariculture activity, and no human habitation or mariculture activity, respectively. The results show that the prevalence of coral diseases in Genting, Sambangan, and Seruni were significantly different (p < 0.01). However, there was no significant correlation between the nutrient concentrations (N and P) and coral disease prevalence (R ; p = 0.07 for nitrate and R ; p = 0.058 for phosphate). The nutrients on the islands affected by marine fish cages tended to increase. We suggest that the continuation of orderly ecosystem monitoring, with increasing sample sizes, in Karimunjawa is urgently needed.