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In order to promote the management and protection of urban water bodies, a survey of large benthic invertebrate communities was carried out on 23 river sections in Suzhou. On this basis, the core indicators suitable for urban water ecological health assessment were selected by analyzing the distribution range, discrimination ability and correlation of the candidate indicators. The ratio method was used to calculate the core index values, and the macrobenthic invertebrate biological integrity index value (Benthic Macroinvertebrate Index of Biotic Integrity, BIBI value) were obtained by accumulating and summing. The results show that 22 species of macrobenthic invertebrates were found in the Suzhou urban water and reference points, belonging to 3 phyla, 6 classes, 9 orders and 14 families. After screening, the BIBI that was suitable for evaluation of Suzhou was composed of the following 6 indicators: the total number of taxons, the number of arthropod taxa, the Shannon-Wiener diversity index, the percentage of widespread species, the percentage of individuals in the class of insects, and the percentage of individuals in pollution-tolerant groups. The optimal expected value of the calculated BIBI value is 4.01, even the BIBI value ≥ 4.01 is healthy, 3.01-4.01 is good, 2.01-3.01 is fair, 1.01-2.01 is poor, and <1.01 is extremely poor(the interval range is left closed and right open, and BIBI value ≥ 0). According to the results of BIBI, the ecological health of the water in Suzhou was uneven. There were more fair and good sites than healthy ; the health status of each point in different seasons is different. The correlation analysis between BIBI and various water quality factors proves that BIBI can be used to evaluate the ecological health of urban water and has scientific guiding significance for the evaluation of urban water ecological health. [ABSTRACT FROM AUTHOR]

A previous survey reported that swimming crabs Portunus trituberculatus (Miers, 1976) in the East China Sea may have a low risk of sperm limitation under the current nonselective fishing practices. In this study, the possible mechanism of avoiding sperm limitation was investigated in a mating season (from July to November 2007) from a male perspective. Males reached 50% gonadal maturity at a carapace length of 99.4 mm and the reproductive measures (vas deferens weights, sperm number, and sperm concentration retained in the vasa deferentia) did not differ significantly throughout the mating season. As shown for other decapods, the quantity of seminal material in the vasa deferentia increased significantly with male size, without a concomitant change in sperm concentration. The proportion of stored sperm transferred at a single mating was calculated, and the results showed that males exhibited low sperm transfer at each mating, regardless of size. These findings indicate that the current fishery practices for P. trituberculatus may have little impact on the quantity of sperm stored by males throughout the mating season. This would guarantee that males of all sizes retain the capacity to mate throughout the breeding season, and, moreover, provide sufficient sperm to fertilize eggs spawned by their mates and reduce the risk of sperm limitation under the current fishing practices in the East China Sea. KEY WORDS: Portunus trituberculatus, sperm storage, nonselective fishery, East China Sea, sperm limitation, INTRODUCTION Sperm limitation occurs when the sperm supply of males is insufficient to fertilize the total number of potential eggs of females. Many studies on exploited wild decapods have revealed [...]