Atlantic Croaker Micropogonias undulatus, Black Drum Pogonias cromis, Spot Leiostomus xanthurus, and Weakfish Cynoscion regalis have shown species‐specific, varying trends in abundance despite general declines in commercial landings throughout the Delaware River estuary. Identifying how environmental factors and climatic processes affect fishes at multiple life stages is needed to enhance the precision of regulatory actions for managed species. Species‐, area‐, and age‐specific indices were compared with depth, salinity, temperature, the Atlantic Multidecadal Oscillation (AMO), and the North Atlantic Oscillation (NAO) to explore potential relationships as well as temporal and spatial parameters. Our results demonstrate that station (15 indices), salinity (14 indices), the AMO and NAO (13 indices each), and depth and temperature (12 indices each) served as important components for models of abundance for 17 species‐, age‐, and area‐specific combinations from 1991 to 2016. Significant time series trends were detected in six of the modeled indices of abundance, including baywide indices of age‐1 Weakfish (decline) and age‐0 Atlantic Croaker (increase); age‐0 Atlantic Croaker (increase) and Weakfish (decline) in Delaware; and age‐1 Spot (decline) and Weakfish (increase) in Delaware. Our results demonstrate how multiple fixed‐station surveys can be combined to quantitatively assess environmental and climatic effects correlated with species‐, age‐, and area‐specific levels of abundance, suggesting that climatic signals are affecting smaller‐scale environmental variables that in turn affect relative abundance.

ECONOMICconsiderations lead to the use of powdered derris or cube, or extracts made from them, as insecticides instead of the highly active principles, rotenone and its relatives, which have been isolated from these plants. Although in the earlier studies of the action of derris it was believed that rotenone was the essential constituent, recent work (S, 5) has strengthened the view that the roots of derris and cube possess more insecticidal activity than can be accounted for by their rotenone content. Experiments reported in the preceding paper (4) indicate that rotenone may under certain circumstances be distinctly toxic to warm-blooded animals and must, therefore, be considered as potentially toxic to man.The present report is a similar study of the toxicity of derris and certain extracts made from it for warm-blooded animals, with an attempt at correlation of the findings with the rotenone content as determined chemically, and with the toxicity for insects as determined on house flies.

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