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Timothy E. Targett - One of the best experts on this subject based on the ideXlab platform.
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Movement of juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus in relation to diel-cycling hypoxia in an estuarine tidal tributary
Marine Ecology Progress Series, 2013Co-Authors: Damian C. Brady, Timothy E. TargettAbstract:Fish movement and the spatial and temporal dynamics of hypoxia determine hypoxia exposure and the effect of poor water quality on nursery habitat function. Although water quality criteria for dissolved oxygen (DO) are well defined, hypoxia exposure of juvenile estuary-depen- dent fishes in situ is largely unknown. Thirty-one juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus were implanted with acoustic tags. Fish were acclimated for 5 d to either DO saturation or diel-cycling hypoxia (cycling between 11.0 and 2.0 mg O2 l �1 ). Fish were released during summer into Pepper Creek, Delaware, an estuarine tributary. A logistic generalized addi- tive model with generalized estimating equations was used to determine which environmental covariates significantly discriminated between movement types. Individual fish tracks were over- lain on spatiotemporal contour plots of DO that highlight behavioral avoidance thresholds deter- mined in the laboratory. Most models showed that DO, tide, and the spatial DO gradient were sig- nificant predictors of movement. Saturation-acclimated fish generally avoided DO
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movement of juvenile weakfish cynoscion regalis and spot Leiostomus Xanthurus in relation to diel cycling hypoxia in an estuarine tidal tributary
Marine Ecology Progress Series, 2013Co-Authors: Damian C. Brady, Timothy E. TargettAbstract:Fish movement and the spatial and temporal dynamics of hypoxia determine hypoxia exposure and the effect of poor water quality on nursery habitat function. Although water quality criteria for dissolved oxygen (DO) are well defined, hypoxia exposure of juvenile estuary-depen- dent fishes in situ is largely unknown. Thirty-one juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus were implanted with acoustic tags. Fish were acclimated for 5 d to either DO saturation or diel-cycling hypoxia (cycling between 11.0 and 2.0 mg O2 l �1 ). Fish were released during summer into Pepper Creek, Delaware, an estuarine tributary. A logistic generalized addi- tive model with generalized estimating equations was used to determine which environmental covariates significantly discriminated between movement types. Individual fish tracks were over- lain on spatiotemporal contour plots of DO that highlight behavioral avoidance thresholds deter- mined in the laboratory. Most models showed that DO, tide, and the spatial DO gradient were sig- nificant predictors of movement. Saturation-acclimated fish generally avoided DO <2.8 mg O2 l �1 by increasing swimming speed and using tidal flow to facilitate escape. An exception to tidally aided movement occurred when a flooding tide appeared to trap smaller fish in spatially extensive hypoxia. Diel-cycling hypoxia acclimated weakfish appeared to have a lower avoidance threshold of ~1.4 mg O2 l �1 . Downstream movements were far more frequent than upstream movements, possibly because late stage juveniles were moving out of the estuary. The relationship between tributary residency and the spatial extent of hypoxia suggests that there is a tradeoff between risk of hypoxic exposure and energetic benefits of remaining in productive areas.
Damian C. Brady - One of the best experts on this subject based on the ideXlab platform.
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Movement of juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus in relation to diel-cycling hypoxia in an estuarine tidal tributary
Marine Ecology Progress Series, 2013Co-Authors: Damian C. Brady, Timothy E. TargettAbstract:Fish movement and the spatial and temporal dynamics of hypoxia determine hypoxia exposure and the effect of poor water quality on nursery habitat function. Although water quality criteria for dissolved oxygen (DO) are well defined, hypoxia exposure of juvenile estuary-depen- dent fishes in situ is largely unknown. Thirty-one juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus were implanted with acoustic tags. Fish were acclimated for 5 d to either DO saturation or diel-cycling hypoxia (cycling between 11.0 and 2.0 mg O2 l �1 ). Fish were released during summer into Pepper Creek, Delaware, an estuarine tributary. A logistic generalized addi- tive model with generalized estimating equations was used to determine which environmental covariates significantly discriminated between movement types. Individual fish tracks were over- lain on spatiotemporal contour plots of DO that highlight behavioral avoidance thresholds deter- mined in the laboratory. Most models showed that DO, tide, and the spatial DO gradient were sig- nificant predictors of movement. Saturation-acclimated fish generally avoided DO
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movement of juvenile weakfish cynoscion regalis and spot Leiostomus Xanthurus in relation to diel cycling hypoxia in an estuarine tidal tributary
Marine Ecology Progress Series, 2013Co-Authors: Damian C. Brady, Timothy E. TargettAbstract:Fish movement and the spatial and temporal dynamics of hypoxia determine hypoxia exposure and the effect of poor water quality on nursery habitat function. Although water quality criteria for dissolved oxygen (DO) are well defined, hypoxia exposure of juvenile estuary-depen- dent fishes in situ is largely unknown. Thirty-one juvenile weakfish Cynoscion regalis and spot Leiostomus Xanthurus were implanted with acoustic tags. Fish were acclimated for 5 d to either DO saturation or diel-cycling hypoxia (cycling between 11.0 and 2.0 mg O2 l �1 ). Fish were released during summer into Pepper Creek, Delaware, an estuarine tributary. A logistic generalized addi- tive model with generalized estimating equations was used to determine which environmental covariates significantly discriminated between movement types. Individual fish tracks were over- lain on spatiotemporal contour plots of DO that highlight behavioral avoidance thresholds deter- mined in the laboratory. Most models showed that DO, tide, and the spatial DO gradient were sig- nificant predictors of movement. Saturation-acclimated fish generally avoided DO <2.8 mg O2 l �1 by increasing swimming speed and using tidal flow to facilitate escape. An exception to tidally aided movement occurred when a flooding tide appeared to trap smaller fish in spatially extensive hypoxia. Diel-cycling hypoxia acclimated weakfish appeared to have a lower avoidance threshold of ~1.4 mg O2 l �1 . Downstream movements were far more frequent than upstream movements, possibly because late stage juveniles were moving out of the estuary. The relationship between tributary residency and the spatial extent of hypoxia suggests that there is a tradeoff between risk of hypoxic exposure and energetic benefits of remaining in productive areas.
Cynthia M Jones - One of the best experts on this subject based on the ideXlab platform.
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temperature and salinity effects on strontium incorporation in otoliths of larval spot Leiostomus Xanthurus
Canadian Journal of Fisheries and Aquatic Sciences, 2004Co-Authors: Gretchen Bath Martin, Simon R. Thorrold, Cynthia M JonesAbstract:Temperature dependence of strontium/calcium (Sr/Ca) ratios in foraminiferal calcite and coral aragonite is well established; however, factors controlling Sr/Ca ratios in fish otoliths remain obscure. To assess temperature dependence of Sr/Ca in marine fish otoliths, we reared spot (Leiostomus Xanthurus) larvae under controlled temperature (1726 °C) and salinity (15 and 25). We found a significant linear relationship between temperature and Sr/Ca ratios, with a sensitivity of approximately 5%·°C1. Otolith Sr/Ca values were also significantly higher at a salinity of 25 vs. 15, after accounting for differences in dissolved Sr/Ca ratios in the ambient water, with a sensitivity of approximately 1%/salinity (). These observations complicate the use of Sr/Ca ratios to determine temperature histories of spot larvae, because accurate temperature reconstructions are possible only with a priori knowledge of both ambient salinity and dissolved Sr/Ca ratios. Fully marine species residing in oceanic waters will ...
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Age, growth and the potential for growth overfishing of spot (Leiostomus Xanthurus) from the Chesapeake Bay, eastern USA
Marine and Freshwater Research, 2004Co-Authors: Kevin R. Piner, Cynthia M JonesAbstract:Spot (Leiostomus Xanthurus) are a popular commercial and sport fish in the Chesapeake Bay region (USA), but have not been managed with age-based models because of a lack of information on vital rates. This study determined that transversely sectioned otoliths were the most appropriate structure to age spot, and subsequently used those ages to estimate biological parameters and evaluate the potential for growth overfishing. Because spot are short-lived, this study explored estimating population parameters using both whole annulus counts and fractional ages. Although fractional ages may be more realistic, parameters estimated using fractions of a year should be interpreted with caution. Growth of spot was rapid (84% of length attained in the first year), the natural mortality rate was high (59% year−1), and the total mortality rate (natural + fishing) was very high (80–94% year−1). Spot maximised cohort biomass early in life (≈1 year) and were relatively impervious to growth overfishing. This study illustrates the difficulty in providing management advice for species that maximise cohort biomass about the same time as their first potential spawning event. This study also documents that high exploitation rates and size selective fishing gear probably affect estimates of population parameters.
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Incorporation of strontium, cadmium, and barium in juvenile spot (Leiostomus Xanthurus) scales reflects water chemistry
Canadian Journal of Fisheries and Aquatic Sciences, 2000Co-Authors: Brian K. Wells, Simon R. Thorrold, Gretchen E. Bath, Cynthia M JonesAbstract:We investigated the hypothesis that strontium:calcium (Sr:Ca), cadmium:calcium (Cd:Ca), and barium:calcium (Ba:Ca) composition in scales reflects that of the ambient seawater in which fish were reared under controlled experimental conditions. Juvenile spot (Leiostomus Xanthurus) were held in replicate tanks containing four different concentrations of Sr, Cd, and Ba maintained at either 20 or 25°C for a total of 42 days. The elemental composition of scales from these fish was analyzed at the termination of the experiment, using isotope dilution inductively coupled plasma mass spectrometry (ICP-MS). Sr, Cd, and Ba levels in the scales, expressed as ratios to Ca, were linearly related to environmental concentrations, indicating that the elements were incorporated in constant proportions to levels in the ambient water. Temperature had no measurable effect on the uptake of Sr, Cd, or Ba into the scales. Finally, Sr:Ca and Ba:Ca ratios in scales were highly correlated with levels in the otoliths from the same t...
Jay R. Stauffer - One of the best experts on this subject based on the ideXlab platform.
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avoidance behavior of morone americana Leiostomus Xanthurus and brevoortia tyrannus to strobe light as a method of impingement mitigation
Environmental Science & Policy, 2000Co-Authors: David R Sager, Charles H Hocutt, Jay R. StaufferAbstract:Abstract The use of strobe lights and strobe light-bubble curtain combinations were evaluated as behavioral guidance systems to reduce impingement via avoidance behavior by estuarine fish. White perch (Morone americana), spot (Leiostomus Xanthurus) and menhaden (Brevoortia tyrannus) were tested in an experimental flume for avoidance to strobe lights, bubble curtains and strobe light-bubble curtain combinations at different water velocities, strobe flash rates and light acclimation (light and dark). The possible accommodation of fish to strobe light was also tested using a microcomputer and on-line biomonitoring chamber examining alterations in breathing rates over time. Avoidance of strobe light ranged from 8–36% for white perch, 8–100% for spot and 8–68% for menhaden depending on the conditions tested. Statistical analyses indicated significant avoidance by white perch at most flash rates with a 0.2 ms−1 flow rate and at 120 and 300 flashes min−1 with 0.3 and 0.5 ms−1 flows. Spot had significant avoidance under most conditions. Menhaden had significant avoidance for all flash rates at 0.2 ms−1 flows and for 300 and 600 flashes min−1 at flows of 0.3 and 0.5 ms−1. All species exhibited little avoidance of bubble curtains alone. Strobe light-bubble curtain combinations had avoidance results of 3–58% for white perch, 21–85% for spot and 9–81% for menhaden. Spot and menhaden exhibited significant avoidance for most conditions at 0.2 and 0.5 ms−1 flows. White perch had significant avoidance for most conditions at 0.2 ms−1 flows, but no avoidance at 0.5 ms−1. The biomonitoring system indicated that little, if any, accommodation took place during 24 h. Strobe light and strobe-bubble curtain combinations elicited the highest avoidance results at flash rates ≥300 min−1 and low water velocities. Strobe light systems may reduce impingement rates but must be evaluated on site specific needs and conditions.
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Base and stressed ventilation rates for Leiostomus Xanthurus Lacépède and Morone americana (Gmelin) exposed to strobe lights
Journal of Applied Ichthyology, 2000Co-Authors: David R Sager, C. H. Hocutt, Jay R. StaufferAbstract:Summary A biomonitoring system interfaced with a microcomputer was used to monitor ventilation rates for white perch (Morone americana) and spot (Leiostomus Xanthurus) under baseline and stressed conditions caused by strobe lights. Tests were conducted on light- and dark-acclimated specimens. These two estuarine species have been found to exhibit avoidance behavior to strobe lights. Potential accommodation to the strobe light stimulus was explored over a 24 h period. The biomonitoring system successfully recorded ventilation rates under baseline and stressed conditions. Baseline mean ventilation rates for 0.5 h intervals ranged from 1 count per minute (cpm) to 97 cpm for light-acclimated white perch with an overall mean for 24 h (x) of 41 cpm. Mean stressed rates ranged from 1 to 100 cpm with an overall mean of 44 cpm. Baseline rates for dark-acclimated white perch ranged from 1 to 79 cpm (x = 35 cpm), with stressed rates from 2 to 83 cpm (x = 30 cpm). Light-acclimated spot had baseline ventilation rates ranging from 3 to 146 cpm (x = 42 cpm), while stressed rates ranged from 2 to 134 cpm (x = 36 cpm). Mean baseline rates for dark-acclimated spot ranged from 1 to 94 cpm (x = 40 cpm), and stressed rates ranged from 1 to 72 cpm (x = 25 cpm). The difference in ventilation rates between base and stressed conditions (as absolute values) for light-acclimated white perch over the 24 h experiments ranged from 0 to 43 cpm (x = 11.01 cpm). Dark-acclimated white perch had differences ranging from 0 to 78 cpm (x = 11.13 cpm). Light-acclimated spot had differences ranging from 0 to 101 cpm (x = 14.68 cpm). Dark-acclimated spot had differences ranging from 0 to 70 cpm (x = 20.56 cpm). Ventilation rates varied between species and among individuals within a species. Ventilation rates were generally lower for dark-acclimated specimens. For both species under all conditions, the base and stressed rates were significantly (P < 0.05) different during the 24 h period. However, dark-acclimated specimens exhibited a more distinct difference than light-acclimated specimens. The lack of accommodation to strobe light and a stronger reaction under dark conditions indicate that strobe lights continue to offer potential as behavioral guidance systems for these species.
Simon R. Thorrold - One of the best experts on this subject based on the ideXlab platform.
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temperature and salinity effects on magnesium manganese and barium incorporation in otoliths of larval and early juvenile spot Leiostomus Xanthurus
Marine Ecology Progress Series, 2005Co-Authors: Gretchen Bath Martin, Simon R. ThorroldAbstract:The use of otolith chemistry to delineate fish populations and trace migration pathways is premised on a significant correlation between the elemental composition of otoliths and physico- chemical properties of the ambient environment. However, few experiments have been rigorously designed to address the effects of temperature and salinity on the elemental composition of otoliths. We examined the effects of temperature and salinity on the incorporation of magnesium (Mg), man- ganese (Mn), and barium (Ba) in the otoliths of larval and early juvenile spot Leiostomus Xanthurus by rearing fish in the laboratory under controlled environmental conditions. L. Xanthurus are an estu- arine dependent species that traverse varying temperature and salinity regimes throughout their life histories. It is important, therefore, to understand the influence of physicochemical properties of dif- ferent water masses before attempting to reconstruct important life history transitions based on vari- ations in otolith chemistry. Both (Mg/Ca)otolith and the Mg partition coefficient, DMg, were not signifi- cantly affected by either temperature or salinity, but were correlated with otolith precipitation and somatic growth rates. Temperature and salinity had significant interaction effects on DMn, but not on (Mn/Ca)otolith. Finally, DBa was influenced by salinity but not temperature. These results highlight the complex nature of elemental deposition in otoliths, and suggest that both environmental and physio- logical effects likely influence elemental ratios in fish otoliths.
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temperature and salinity effects on strontium incorporation in otoliths of larval spot Leiostomus Xanthurus
Canadian Journal of Fisheries and Aquatic Sciences, 2004Co-Authors: Gretchen Bath Martin, Simon R. Thorrold, Cynthia M JonesAbstract:Temperature dependence of strontium/calcium (Sr/Ca) ratios in foraminiferal calcite and coral aragonite is well established; however, factors controlling Sr/Ca ratios in fish otoliths remain obscure. To assess temperature dependence of Sr/Ca in marine fish otoliths, we reared spot (Leiostomus Xanthurus) larvae under controlled temperature (1726 °C) and salinity (15 and 25). We found a significant linear relationship between temperature and Sr/Ca ratios, with a sensitivity of approximately 5%·°C1. Otolith Sr/Ca values were also significantly higher at a salinity of 25 vs. 15, after accounting for differences in dissolved Sr/Ca ratios in the ambient water, with a sensitivity of approximately 1%/salinity (). These observations complicate the use of Sr/Ca ratios to determine temperature histories of spot larvae, because accurate temperature reconstructions are possible only with a priori knowledge of both ambient salinity and dissolved Sr/Ca ratios. Fully marine species residing in oceanic waters will ...
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Incorporation of strontium, cadmium, and barium in juvenile spot (Leiostomus Xanthurus) scales reflects water chemistry
Canadian Journal of Fisheries and Aquatic Sciences, 2000Co-Authors: Brian K. Wells, Simon R. Thorrold, Gretchen E. Bath, Cynthia M JonesAbstract:We investigated the hypothesis that strontium:calcium (Sr:Ca), cadmium:calcium (Cd:Ca), and barium:calcium (Ba:Ca) composition in scales reflects that of the ambient seawater in which fish were reared under controlled experimental conditions. Juvenile spot (Leiostomus Xanthurus) were held in replicate tanks containing four different concentrations of Sr, Cd, and Ba maintained at either 20 or 25°C for a total of 42 days. The elemental composition of scales from these fish was analyzed at the termination of the experiment, using isotope dilution inductively coupled plasma mass spectrometry (ICP-MS). Sr, Cd, and Ba levels in the scales, expressed as ratios to Ca, were linearly related to environmental concentrations, indicating that the elements were incorporated in constant proportions to levels in the ambient water. Temperature had no measurable effect on the uptake of Sr, Cd, or Ba into the scales. Finally, Sr:Ca and Ba:Ca ratios in scales were highly correlated with levels in the otoliths from the same t...