Diversity Of Fish Communities In The Adjacent Waters Of The Yellow River Delta

The Yellow River Delta is located in the south of the Bohai Sea and the north of the Shandong Peninsula.Its adjacent waters include the Yellow River estuary and the western waters of Laizhou Bay.The rich nutrients in the estuary waters have formed a natural environment suitable for the growth,development,and reproduction of marine organisms.Under the influence of diversion of the Yellow River,deterioration of the ecological environment,and human production activities,the marine biological communities in the Yellow River Delta and its adjacent waters have been seriously affected,resulting in varying degrees of damage to marine biodiversity.Therefore,the protection of marine biodiversity in the coastal waters of the Yellow River Delta is even more urgent,and the protection of fish biodiversity is also an important component.This paper takes the 21 stations selected from the Yellow River Delta and its adjacent waters(119°05′-120°00′E、37°12′-37°40′N)as the study area.Through field sampling and historical survey data collection,the species composition list of fish in the adjacent waters of Yellow River Delta from 2012 to 2021 was systematically sorted out,and the species ecological composition,taxonomic diversity index and their annual changes were calculated and analyzed.The similarity and stability of fish communities were analyzed and studied,and the integrity of fish in the adjacent waters of the Yellow River Delta was evaluated using correlation analysis.(1)According to the research statistics,there were 49 species of fishes in the adjacent waters of Yellow River Delta from 2012 to 2021,all of which were teleost fishes,including 10 orders,27 families and 46 genera.Compared with the historical data,the ecological types of fish communities have not changed significantly in the past10 years.Warm temperate fish,continental shelf migratory fish and bottom fish are still the main fish types in the adjacent waters of Yellow River Delta.During the past 10years,the annual biomass of upper and warm temperate fish,mainly Konosirus punctatus,fluctuated significantly,which is the main reason for the changes in fish resources.Warm temperate fishes have a short life cycle,low trophic level,great environmental impact on resource dynamics,and strong resource recovery ability.The wide distribution of suitable habitat areas in the waters near the Yellow River estuary is the main reason for their large biomass since the 1950s,and also the reason for the dominant position of warm temperate fishes in the waters near the Yellow River Delta.(2)The taxonomic diversity index of fish in the Yellow River Delta and its adjacent waters has shown a slight downward trend in the past decadeΔ~+Value and fish calculated from the historical Yellow River Delta fish listΔ~+The survey value is outside the 95%confidence curve.The value(59.23)is smaller than other areas of Shandong offshore in the same period,while theλ~+value(113.69)is larger than other sea areas,indicating that compared with other sea areas in Shandong,the genetic relationship between common fish communities in the Yellow River Delta and its adjacent sea areas is the closest,but the classification status relationship between fish communities is the lowest.(3)The Shannon Wiener diversity index of fish in the adjacent waters of Yellow River Delta showed a downward trend from 2014 to 2016.After 2016,the Shannon Wiener diversity index increased.In recent years,the fish biodiversity has a trend of improvement.From the ABC curve,it can be seen that in individual years(2014),the community was highly disturbed,with significant fluctuations in biomass,while in other years,the community was less disturbed.From the perspective of species similarity coefficient and community stability,most of the similarity coefficients in recent 10 years are medium or very similar.The fish species in Yellow River Delta have not changed much,and the community tends to dynamic balance.(4)The Shannon Wiener diversity index of fish in the adjacent waters of Yellow River Delta showed a downward trend from 2014 to 2016.After 2016,the Shannon Wiener diversity index increased.In recent years,the fish biodiversity has a trend of improvement.From the ABC curve,it can be seen that in individual years(2014),the community was highly disturbed,with significant fluctuations in biomass,while in other years,the community was less disturbed.From the perspective of species similarity coefficient and community stability,most of the similarity coefficients in recent 10 years are medium or very similar.The fish species in Yellow River Delta have not changed much,and the community tends to dynamic balance.