Comparison of Seaweed Growth, Fish Abundance and Diversity in Deep Water Floating Raft with Tubular Nets and Shallow Water Off-bottom lines Seaweed Farms

Abstract

This study compared the growth performance of Eucheuma denticulatum, fish abundance anddiversity between deep water (using tubular nets) versus shallow water (off-bottom) seaweedfarming methods. For each farming method, three plots were set and fish abundance, diversity andseaweed growth rates were measured at intervals of 15 days. Belt transects measuring 10 m x 4 meach, were established on seaweed farms for fish observations. Fish were identified to the lowestpossible taxonomic level by underwater census. The results showed that the growth rate of E.denticulatum in deep water farms was slightly higher at an average daily growth rate (DGR) of3.42 ± 0.18% day−1 compared with 3.01 ± 0.27% day−1 for shallow water farms but with nosignificant differences (p = 0.079) likely due to higher herbivory in the deep water farms. Fishabundance and diversity were higher in deep water farms but insignificant (t (34) = 0.69, p = 0.49and t (34) = 0.424, p = 0.67, respectively). Habitat complexity and seaweed growth rate were almostsimilar for both farming methods hence attracting comparable numbers of fish. Further studies arerecommended on fish community structures, differences between the two farming methods andeffects of herbivory. Keywords: E. denticulatum; seaweed farming methods; growth; fish diversity and abundance