Abstract
Acoustic surveys were used to locate coastal Pacific herring (Clupea pallasii) spawning grounds, and the spatial and temporal patterns of their spawning in Jinhae Bay, Korea were examined. We deployed mooring with a newly designed autonomous echosounder for ~70 days during the Pacific herring spawning season in Jinhae Bay, from January to April 2018. At the same time, ship-based acoustic surveys were conducted to identify the spatial distribution twice, at 38 and 120 kHz, onboard the fishing vessel in January and April 2018 in the bay. Fish school signals, including those from adult Pacific herring, are often detected through ship-based acoustic surveys in January, from outside the bay. In the spring, weak scattering signals from fish larvae and zooplankton were continuously detected inside the bay. Backscatter at the mooring in the center of Jinhae Bay was low from mid-January to early March, gradually increasing to higher levels until the end of March. The backscatter observed from the mooring correlated well with ship-based acoustic surveys in the center of the bay. This study proposes that the mooring type acoustic echosounder is a valuable tool for temporal abundance information and other aspects of fish behavior.
Highlights
IntroductionIntroduction published maps and institutional affilA species of the herring family (belonging to the order Clupeiformes), Pacific herring (Clupea pallasii) is a cold-water fish that spawns and grows in the coastal waters of Korea, mostly during the winter season, and moves to the high-latitude Bering Sea as the water temperature rises due to seasonal changes [1]
Introduction published maps and institutional affilA species of the herring family, Pacific herring (Clupea pallasii) is a cold-water fish that spawns and grows in the coastal waters of Korea, mostly during the winter season, and moves to the high-latitude Bering Sea as the water temperature rises due to seasonal changes [1]
As a result of the survey of stationary net fishing performed twice in order to compare the data obtained from the echosounders in Jinhae Bay, 291 Pacific herring with a total weight of 42.18 kg were caught
Summary
Introduction published maps and institutional affilA species of the herring family (belonging to the order Clupeiformes), Pacific herring (Clupea pallasii) is a cold-water fish that spawns and grows in the coastal waters of Korea, mostly during the winter season, and moves to the high-latitude Bering Sea as the water temperature rises due to seasonal changes [1]. While Korea recorded high catches of the Pacific herring until the 1970s, the amount of fishery resources plummeted due to overfishing and environmental pollution. Since the early 2000s, catches of the Pacific herring have increased every year due to the improved management of fisheries resources [2,3]. These herring catches are related to climate change. The water temperature dropped from 5 ◦ C to 1–2 ◦ C at a depth of 200 m in 1992–1993 in the same area [4] This may have led to an increase in the amount iations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
