Distribution and Abundance of Japanese Anchovy Engraulis japonicus and Other Fishes in Asan Bay, Korea, estimated Hydroacoustic Survey

Abstract

The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, m 2 /mile 2 ) for 0.25 n•mile along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (△MVBS) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length−weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24.1−93.3 tons, and other fish at 40.6−88.4 tons from July to October 2012. The estimated anchovy biomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.

Small-Scale Spatiotemporal Pattern in the Spawning of Pacific Herring (Clupea pallasii) in the Jinhae Bay, Korea, Estimated Using Hydroacoustic Survey

“…Acoustic survey using 70 kHz frequency is mainly used for the detection of medium-size fish among general zooplankton such as Antarctic krill [29]. In data analysis, the MVBS technique was used to remove zooplankton echoes within the 38 kHz echoes [12], while fish echoes were removed from within the 120 kHz echoes [21]. The 70 kHz echoes obtained by the mooring system differed significantly from those of larval Pacific herring having swimbladders [23] and large copepods mainly distributed in Jinhae Bay [25], with the largest difference being more than 27 dB per single individual.…”

“…The data from the ship-based echosounder were analyzed for both 38 kHz and 120 kHz. Noise was removed from the SV data obtained while the ship was in motion, and the difference in mean volume backscattering strength (∆MVBS) was used to separate adult fish (2 dB < ∆MVBS 38-120 < 20 dB) from fish larvae and zooplankton (2 dB < ∆MVBS 120-38 < 20 dB) [12,21]. In addition, the data were extracted by converting into average NASC, in the same way as the results from the moored echosounder for each frequency.…”

“…Other countries perform hydroacoustic surveys of various migratory fishes such as the Alaskan cod, Bering Sea pollock, Peruvian anchoveta, and sardine on a regular basis. Korea has published limited research results on the distribution and current amounts of major fish species using acoustic equipment in Asan Bay in South Chungcheong Province (anchovies), Tongyeong in South Gyeongsang Province, Yeosu in South Jeolla Province, and the waters near Jeju and around artificial reefs installed in coastal areas [11][12][13]. In addition to spatial research using acoustic methods, the movement patterns of fishes and fluctuations in zooplankton have been studied through limited-time or long-term monitoring using moored acoustic equipment such as multi-beam image sonar, acoustic zooplankton fish profiler, and acoustic Doppler current profiler, owing to the advancement of technology [14][15][16].…”

Acoustic Characteristics of Largehead Hairtail (Trichiurus japonicus) Using Multi-Frequency Detection in the Southern Sea, South Korea

“…These include echosounder studies on the chub mackerel (Scomber japonicus) and jack mackerel (Trachurus japonicus) in the seas around Jeju Island, as well as studies on the Pacific anchovy (Engraulis japonicus) in the Southern Sea. Additionally, research has been conducted to investigate the distribution and changes in the distribution of pelagic fish in artificial reefs in regions such as Jeju Island, Asan Bay, and Gwangyang Bay [12][13][14][15].…”

Comparison of Echogram Analysis Methods for Evaluating the Sound-scattering Layer

“…, . (Hone and Jeck, 1999), 2 (Miyashita et al, 1997;Kang, 2002;Kloser et al, 2002;McKelvey and Wilson, 2006;Kim et al, 2013;Lee et al, 2014). , (Lee et al, 2012;Hwang et al, 2015).…”