AUTHOR=Zuo Tao , Wang Di , Li Yongtao , Niu Mingxiang , Cheng Zhaolong , Wang Jun 

TITLE=Occurrence of the calanoid copepod Acartia (Odontacartia) ohtsukai in Laizhou Bay, the Bohai Sea, China, and its relationship with environmental factors

JOURNAL=Frontiers in Marine Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1378085

DOI=10.3389/fmars.2024.1378085

ISSN=2296-7745

ABSTRACT=<p>In this study, we examined the short-term variation in the abundance of copepod <italic>Acartia</italic> specimens, identified previously as <italic>Acartia pacifica</italic>, in Laizhou Bay, an estuarine bay in the southern Bohai Sea in northern China. Monthly samples were collected from May 2011 to April 2012, excluding December 2011 and January to February 2012 due to ice. Based on its morphological characteristics, <italic>Acartia ohtsukai</italic> was distinguishable from <italic>A. pacifica</italic> for the first time in Laizhou Bay. <italic>A. ohtsukai</italic> was sporadically present from summer to autumn, with the highest abundance and occurrence in September. It appeared in June when the water temperature was above 20°C, and disappeared in November when the water temperature decreased to less than 10°C. During the surveyed months, <italic>A. ohtsukai</italic> was more commonly found inshore with salinity less than 28 than offshore in the bay. Correlation analysis revealed that temperature and chlorophyll a concentration significantly influenced the monthly variations in <italic>A. ohtsukai</italic> abundance. We also compared the occurrence of <italic>A. ohtsukai</italic> with that of three species from the genus <italic>Tortanus</italic> (<italic>Tortanus derjugini</italic>, <italic>Tortanus forcipatus</italic>, and <italic>Tortanus spinicaudatus</italic>) in Laizhou Bay. The coexistence of <italic>A. ohtsukai</italic> and <italic>T. derjugini</italic> in the bay suggests that their ecological habitats are similar to those of brackish-water species.</p>