scholarly journals Otolith-based growth reconstructions in young-of-year Atlantic silversides Menidia menidia and their implications for sex-selective survival

2019 ◽  
Vol 632 ◽  
pp. 193-204 ◽  
Author(s):  
JW Pringle ◽  
H Baumann
Keyword(s):  
Menidia Menidia ◽  
Selective Survival

scholarly journals You Better Repeat It: Complex CO2 × Temperature Effects in Atlantic Silverside Offspring Revealed by Serial Experimentation

Diversity ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 69 ◽  
Author(s):  
Christopher Murray ◽  
Hannes Baumann
Keyword(s):  
Early Life ◽  
Larval Growth ◽  
Menidia Menidia ◽  
Embryo Survival ◽  
Single Experiment ◽  
Growth And Survival ◽  
Atlantic Silverside ◽  
Co2 Effects ◽  
Experimental Approaches ◽  
Temperature Interactions

Concurrent ocean warming and acidification demand experimental approaches that assess biological sensitivities to combined effects of these potential stressors. Here, we summarize five CO2 × temperature experiments on wild Atlantic silverside, Menidia menidia, offspring that were reared under factorial combinations of CO2 (nominal: 400, 2200, 4000, and 6000 µatm) and temperature (17, 20, 24, and 28 °C) to quantify the temperature-dependence of CO2 effects in early life growth and survival. Across experiments and temperature treatments, we found few significant CO2 effects on response traits. Survival effects were limited to a single experiment, where elevated CO2 exposure reduced embryo survival at 17 and 24 °C. Hatch length displayed CO2 × temperature interactions due largely to reduced hatch size at 24 °C in one experiment but increased length at 28 °C in another. We found no overall influence of CO2 on larval growth or survival to 9, 10, 15 and 13–22 days post-hatch, at 28, 24, 20, and 17 °C, respectively. Importantly, exposure to cooler (17 °C) and warmer (28 °C) than optimal rearing temperatures (24 °C) in this species did not appear to increase CO2 sensitivity. Repeated experimentation documented substantial inter- and intra-experiment variability, highlighting the need for experimental replication to more robustly constrain inherently variable responses. Taken together, these results demonstrate that the early life stages of this ecologically important forage fish appear largely tolerate to even extreme levels of CO2 across a broad thermal regime.

Darwinian fishery science: lessons from the Atlantic silverside (Menidia menidia)

2005 ◽  
Vol 62 (4) ◽  
pp. 730-737 ◽  
Author(s):  
David O Conover ◽  
Stephen A Arnott ◽  
Matthew R Walsh ◽  
Stephan B Munch
Keyword(s):  
Life History ◽  
Theory And Practice ◽  
Winter Mortality ◽  
Menidia Menidia ◽  
Adaptive Genetic Variation ◽  
Atlantic Silverside ◽  
Fishery Science ◽  
Evolutionary Changes ◽  
In The Wild ◽  
Contrary Evidence

The potential of fishing mortality to cause rapid evolutionary changes in life history has received relatively little attention. By focusing only on ecological responses, standard fisheries theory and practice implicitly assume either that genetic influences on life history in the wild are negligible or that natural selection and adaptation is a slow process that can be effectively ignored. Lack of contrary evidence has allowed these assumptions to persist. Drawing upon >25 years of research on the Atlantic silverside (Menidia menidia), we show that adaptive genetic variation in many traits is finely tuned to natural variation in climate. Much of this variation is caused by a gradient in size-selective winter mortality and involves two- to threefold changes in physiological traits that influence population productivity. Many other species are now known to display similar patterns. Harvest experiments show that these traits can evolve rapidly in response to size-selective fishing. Hence, the pool of genotypes that code for life history traits is a highly dynamic property of populations. We argue that the lessons from Menidia are applicable to many exploited species where similar observations would be difficult to obtain and advocate greater use of species models to address fundamental questions in fishery science.

scholarly journals Detecting the Effects of Early-Life Exposures: Why Fecundity Matters

2019 ◽  
Author(s):  
Jenna Nobles ◽  
Amar Hamoudi
Keyword(s):  
Infant Health ◽  
Statistical Significance ◽  
Absolute Magnitude ◽  
Later Life ◽  
Contrast Effects ◽  
Fetal Origins ◽  
Health Trajectories ◽  
Maternal And Infant Health ◽  
Selective Survival ◽  
Early Life Exposures

Prenatal exposures have meaningful effects on health across the lifecourse. Innovations in causal inference have shed new light on these effects. Here, we motivate the importance of innovation in the characterization of fecundity, and prenatal selection in particular. We argue that such innovation is crucial for expanding knowledge of the fetal origins of later life health. Pregnancy loss is common, responsive to environmental factors, and closely related to maternal and fetal health outcomes. As a result, selection into live birth is driven by many of the same exposures that shape the health trajectories of survivors. Lifecourse effects that are inferred without accounting for these dynamics may be significantly distorted by survival bias. We use a set of Monte Carlo simulations with realistic parameters to examine the implications of prenatal survival bias. We find that even in conservatively specified scenarios, true fetal origin effects can be underestimated by 50% or more. In contrast, effects of exposures that reduce the probability of prenatal survival but improve the health of survivors will be overestimated. The absolute magnitude of survival bias can even exceed small effect sizes, resulting in inferences that beneficial exposures are harmful or vice-versa. We also find reason for concern that moderately sized true effects, underestimated due to failure to account for selective survival, are missing from scientific knowledge because they do not clear statistical significance filters. This bias has potential real-world costs; policy decisions about interventions to improve maternal and infant health will be affected by underestimated program impact.

Selective Survival, Aging, and Society

2020 ◽  
pp. 187-205
Author(s):  
Kyriakos S. Markides ◽  
Richard Machalek
Keyword(s):  
Selective Survival

scholarly journals Negative Effects of Diurnal Changes in Acidification and Hypoxia on Early-Life Stage Estuarine Fishes

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Brooke K. Morrell ◽  
Christopher J. Gobler
Keyword(s):  
Early Life ◽  
Fish Larvae ◽  
Life Stage ◽  
Early Life Stage ◽  
Low Ph ◽  
Sensitivity Threshold ◽  
Diurnal Changes ◽  
Menidia Menidia ◽  
Negative Effects ◽  
Low Do

Estuaries serve as important nursery habitats for various species of early-life stage fish, but can experience cooccurring acidification and hypoxia that can vary diurnally in intensity. This study examines the effects of acidification (pH 7.2–7.4) and hypoxia (dissolved oxygen (DO) ~ 2–4 mg L−1) as individual and combined stressors on four fitness metrics for three species of forage fish endemic to the U.S. East Coast: Menidia menidia, Menidia beryllina, and Cyprinodon variegatus. Additionally, the impacts of various durations of exposure to these two stressors was also assessed to explore the sensitivity threshold for larval fishes under environmentally-representative conditions. C. variegatus was resistant to chronic low pH, while M. menidia and M. beryllina experienced significantly reduced survival and hatch time, respectively. Exposure to hypoxia resulted in reduced hatch success of both Menidia species, as well as diminished survival of M. beryllina larvae. Diurnal exposure to low pH and low DO for 4 or 8 h did not alter survival of M. beryllina, although 8 or 12 h of daily exposure through the 10 days posthatch significantly depressed larval size. In contrast, M. menidia experienced significant declines in survival for all intervals of diel cycling hypoxia and acidification (4–12 h). Exposure to 12-h diurnal hypoxia generally elicited negative effects equal to, or of greater severity, than chronic exposure to low DO at the same levels despite significantly higher mean DO exposure concentrations. This evidences a substantial biological cost to adapting to changing DO levels, and implicates diurnal cycling of DO as a significant threat to fish larvae in estuaries. Larval responses to hypoxia, and to a lesser extent acidification, in this study on both continuous and diurnal timescales indicate that estuarine conditions throughout the spawning and postspawn periods could adversely affect stocks of these fish, with diverse implications for the remainder of the food web.

scholarly journals Mercury bioaccumulation increases with latitude in a coastal marine fish (Atlantic silverside, Menidia menidia)

2017 ◽  
Vol 74 (7) ◽  
pp. 1009-1015 ◽  
Author(s):  
Zofia Baumann ◽  
Robert P. Mason ◽  
David O. Conover ◽  
Prentiss Balcom ◽  
Celia Y. Chen ◽  
...  
Keyword(s):  
Marine Fish ◽  
Human Exposure ◽  
Large Scale ◽  
Assimilation Efficiency ◽  
Dry Weight ◽  
Primary Control ◽  
Menidia Menidia ◽  
Atlantic Silverside ◽  
Coastal Marine ◽  
Latitudinal Patterns

Human exposure to the neurotoxic methylmercury (MeHg) occurs primarily via the consumption of marine fish, but the processes underlying large-scale spatial variations in fish MeHg concentrations [MeHg], which influence human exposure, are not sufficiently understood. We used the Atlantic silverside (Menidia menidia), an extensively studied model species and important forage fish, to examine latitudinal patterns in total mercury (Hg) [Hg] and [MeHg]. Both [Hg] and [MeHg] significantly increased with latitude (0.014 and 0.048 μg MeHg·g dry weight−1 per degree of latitude in juveniles and adults, respectively). Four known latitudinal trends in silverside traits help explain these patterns: latitudinal increase in MeHg assimilation efficiency, latitudinal decrease in MeHg efflux, latitudinal increase in weight loss due to longer and more severe winters, and latitudinal increase in food consumption as an adaptation to decreasing length of the growing season. Given the absence of a latitudinal pattern in particulate MeHg, a diet proxy for zooplanktivorous fish, we conclude that large-scale spatial variation in growth is the primary control of Hg bioaccumulation in this and potentially other fish species.

The regulation of metabolic clearance rate of human FSH in mice by variation of the molecular structure of the hormone

1986 ◽  
Vol 112 (3) ◽  
pp. 336-344 ◽  
Author(s):  
Leif Wide
Keyword(s):  
Clearance Rate ◽  
Ovarian Function ◽  
Metabolic Clearance ◽  
Gradual Change ◽  
Metabolic Clearance Rate ◽  
Physiological Importance ◽  
Selective Survival ◽  
Veronal Buffer ◽  
Rapid Clearance ◽  
The Individual

Abstract. The relationship between charge on human FSH (hFSH) molecules and their metabolic clearance rate (MCR) was investigated. The median charge of the hFSH molecules was expressed as their median mobility at electrophoresis in 0.075 m sodium veronal buffer, pH 8.6. MCR was estimated after single iv injection in mice of unfractionated and fractionated extracts of human pituitaries. There was a highly significant (P < 0.001) correlation between charge and MCR both for forms of FSH present within the individual pituitary and for FSH in different pituitaries. After the iv injection there was a gradual change to a more negative median charge of hFSH in plasma. This was explained by the more rapid clearance of the less negatively charged forms of hFSH and thus selective survival of different forms in the circulation. This is a most likely explanation for the differences in median charge between FSH in pituitaries and in sera of men and women of corresponding age. The results suggest that MCR of human FSH is controlled by a gonadal-pituitary feed-back mechanism which involves changes in the structure of the FSH produced by the pituitary. It is suggested that charge is one factor involved in the regulation of the survival of FSH in the circulation and that this is of physiological importance for the control of the ovarian function during the menstrual cycle.

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