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1.
C. G. Bookhout R. J. Monroe R. B. Forward Jr. J. D. Costlow Jr. 《Water, air, and soil pollution》1984,21(1-4):199-216
Survival of Rhithropanopeus harrisii larvae from hatching to first crab stage occurred in Na2CrO4 concentrations from 1.1 to 29.1 ppm. Estimated LC50 for complete zoeal development was 17.8 ppm Na2CrO4 and it was 13.7 ppm for development to first crab stage. A concentration of 1.1 ppm Na2CrO4 was nontoxic, while Na2CrO4 concentrations of 7.2 and 14.5 ppm were sublethal and concentrations of 29.1 to 58.1 ppm were acutely toxic. Low concentrations of Na2Cr04 caused an increase in swimming speed and high concentrations caused a decline. Survival of Callinectes sapidus larvae occurred in Na2CrO4 concentrations from 1.1 to 4.7 ppm. The LC50 for complete zoeal development was estimated to be 2.9 ppm Na2CrO4 and the LC50 for development to first crab stage was estimated to be 1.0 ppm Na2CrO4 The total Cr in sodium chromate is 32% by weight (Tacey,1981), hence, the total Cr concentrations tested were 32% of the Cr salts given above. Statistical analyses of the data on survival, duration and mortality of larvae are presented. 相似文献
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Field-caught larvae of the estuarine crab Rhithropanopeus harrisii have a tidal rhythm of vertical migration when maintained in constant conditions. Laboratory-reared larvae do not show this rhythm. Endogenous tidal vertical migrations aid the retention of these planktonic larvae in estuaries near the parent populations. 相似文献
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A three-dimensional circulation model was used in conjunction with larval fish vertical behaviour models to study the interaction between larval vertical distribution, advection and the outcome of larval transport along the central portion of the east coast of the United States. The circulation model was forced by tides, a northern boundary inflow, and winds. Vertical behaviour models were developed for Atlantic menhaden ( Brevoortia tyrannus ) and spot ( Leiostomus xanthurus ). The purpose of this modelling effort was to investigate the transport pathways of Atlantic menhaden and spot larvae from offshore spawning grounds to estuarine nursery habitats. The coupled circulation and behavioural model demonstrated the importance of along-shelf transport in what is generally thought to be a 'cross-shelf' problem. Cross-shelf transport was associated with bathymetric features, such as shoals. Both physical (e.g. wind) and biological (e.g. changes in larval behaviour) events were responsible for many of the observed patterns in larval transport. Overall, larval transport was determined by circulation but was modified by larval vertical distributions. 相似文献
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Cessation of movement (stop response) is used as a criterion for light reception by the dinoflagellate Gyrodinium dorsum Kofoid. Brief irradiation (2 seconds at 470 nanometers) elicits a stop response in cells any time during the 6-minute interval after removal from growth lights. This stop response is inactivated by exposure for 4 minutes to 470-nanometer light prior to stimulation. Red light (620 nanometers) reactivates this stop response, and far-red light (700 nanometers) reverses this reactivation. This red-far-red photo reversibility is taken as evidence for phytochrome involvement. 相似文献
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Transport of fish larvae through a tidal inlet 总被引：3，自引：0，他引：3
Forward Jr Reinsel Peters Tankersley Churchill Crowder Hettler Warlen & Green 《Fisheries Oceanography》1999,8(S2):153-172
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Rémy Haché Benjamin S. Forward Fabrice Pernet 《Journal of the World Aquaculture Society》2017,48(1):57-69
High‐density (HD) rotifer culture systems have been recently commercialized, but are not commonly used by the aquaculture industry. The aim of this study was to determine if HD systems could be used in cod hatcheries. An enrichment strategy using the commercial products, ArteMac and Protein Selco Plus (Com), was compared with the manufacturer's suggested enrichment, using Pavlova‐DHA (Pav). The Pav enrichment increased the eicosapentaenoic acid (EPA) levels in rotifers, but reduced the docosahexaenoic acid (DHA) and 22:5n‐6 (n‐6DPA, docosapentaenoic acid) levels. Larvae EPA levels in both polar and neutral lipids were relatively stable in the larvae fed with Com‐rotifers; while they were higher in early stages, they were progressively reduced through ontogeny in the Pav‐rotifers fed‐larvae. DHA levels in polar lipids decreased in larvae, particularly when fed with HD‐Pav rotifers. In all larvae, arachidonic acid (ARA) levels increased in the polar and neutral lipids, regardless of treatments. In both lipid fractions, the levels of ARA were quite stable in time, but still higher in larvae fed with Com‐rotifers. Bacterial load was lower in larvae fed with Pav‐rotifers. Denaturing gradient gel electrophoresis (DGGE) bacterial profiles of larvae and rotifers were all similar. This study shows the potential of using HD systems to produce rotifers, but highlights the necessity of adjusting the nutritional composition of rotifers prior to being fed to larvae. 相似文献
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We investigated the effect of stratification on the proteinase activity involved in mobilization of the major soluble approximately 45 kDa storage protein during germination of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seeds. Complete hydrolysis of the approximately 45 kDa protein was observed approximately 7 days after exposure of stratified seeds to germination conditions. Coincident with the onset of mobilization, proteinase activity was detected primarily in microsomal extracts from stratified seeds. Microsomal-associated proteinase activity was most active at pH 8.0 and had a molecular mass > 175 kDa as determined by gelatin SDS-PAGE gels. In vitro digestion of soluble protein extracts indicated that, following stratification, there was a significant increase in proteinase activity and hydrolysis of the approximately 45 kDa storage protein. Whether this increase was a result of activation of preexisting proteinase(s) or de novo synthesis remains unknown. In vitro digestion of soluble protein extracts in the presence of various proteinase inhibitors showed that digestion of the approximately 45 kDa storage protein is mediated primarily by a metalloproteinase and to a lesser degree by a serine proteinase. The accumulation of approximately 25 kDa protein products following in vitro digestion suggests that mobilization of the approximately 45 kDa soluble storage protein is mediated by a multi-step process involving the action of different classes of proteinases. 相似文献
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C. G. Bookhout R. J. Monroe R. B. Forward Jr. J. D. Costlow Jr. 《Water, air, and soil pollution》1984,21(1-4):183-197
The mud aqueous fraction (MAF) and suspended particulate phase (SPP) of low-density lignosulfonate type mud with úerrochrome added were nontoxic to larvae during the complete larval development of Rhithropanopeus harrisii. Five percent (5000 ppm, 0.5 % v/v mud in water) MAF and SPP were not toxic to Callinectes sapidus. Survival of C. sapidus larvae decreased as concentrations of MAF and SPP increased from 5 % (5000 ppm, 0.5 v/v mud in water) to 50% (50000 ppm, 5 % v/v mud in water). No larvae reached the 1st crab stage in 100% (100000 ppm, 10% v/v mud in water) MAF and SPP. Statistical analysis of the data on survival, mortality, and behavior are presented. Blue crab larval behavior is affected by exposure to MAF and SPP with the general effect being a decline in swimming speed. A significant reduction was only observed in 100% MAF but was noticed in 5, 25, 50, and 100% SPP. 相似文献
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