Using bioacoustics and conventional netting methods to assess the initial effectiveness of a newly deployed artificial reef on fish assemblages in Xiangshan Bay near Ningbo, Zhejiang Province, China

Objectives of the study were ascertaining the temporal variation of fish density and biomass as well as the changes in fish species composition in a surveyed area before and after deployment of an artificial reef. The study was initiated within an area of 0.25 km2 in response to a strong demand for fisheries enhancement and resource conservation in Xiangshan Bay, Zhejiang Province, China. This survey data was collected through a SIMRAD EY60 system and bottom trinal nets pre- and post-construction of the artificial reefs, May 2011 to September 2012 in Xiangshan Bay. The raw data were analyzed using fisheries acoustic Echoview (Myriax) software combined with bottom trinal net data. The results showed that estimated fish density, represented by a nautical area scattering coefficient (NASC) at the artificial reef increased by 14.04, 31.10, 17.35% in May, July and September 2012 after construction of the artificial reef, and that the fish biomass increased by 8.92, 29.06, and 18.09% in these three months of 2012 in contrast to 2011. The numbers of fish species varied from 7 to 9 in May, from 10 to 14 in July and from 9 to 12 in September of 2012. These temporal changes in the fishery status were considered as being mainly due to deployment of the artificial reefs in early April 2012.