The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
David O Conover - One of the best experts on this subject based on the ideXlab platform.
-
Full mitochondrial genome sequences reveal new insights about post-glacial expansion and regional phylogeographic structure in the Atlantic silverside (Menidia Menidia)
Marine Biology, 2018Co-Authors: Nicholas K. Fletcher, David O Conover, Aryn P. Wilder, Nina O. Therkildsen, Jeremy B. SearleAbstract:One of the biggest challenges in population genetics of marine species is to uncover subtle phylogeographic patterns masked by large effective population sizes and/or high gene flow. In this paper, we use 189 full mitochondrial genome sequences from the Atlantic silverside ( Menidia Menidia ), obtained during whole nuclear genome re-sequencing, to address this challenge. With this approach, we were able to provide a high-resolution analysis of the demographic history and current genetic structure of the species. We clearly defined a regional genetic structure that is stronger than previously thought. This structure groups the species into three regional subdivisions: (1) south of Cape Cod; (2) Gulf of Maine; and (3) Gulf of St. Lawrence. Among the regional subdivisions, our data reveal that the two northern groups show the greatest divergence despite their adjacency along the latitudinal gradient, while genetic homogeneity within the southern subdivision suggests connectivity throughout its broad geographical distribution. Furthermore, using approximate Bayesian computation (ABC) methods, we inferred that both northern populations are the result of independent colonization events from the south after the Last Glacial Maximum (LGM). Our analyses indicate that at least one of the northern populations has received two waves of colonization, one timed immediately after the LGM and the other timed after the end of the Younger Dryas glacial re-advance. Finally, we found one locus potentially under positive selection in the mitochondrial genome. The results of this study illustrate the power of full mitochondrial genome sequencing in phylogeographic research, and because the Atlantic silverside is known for its clinal phenotypic variation throughout its range, our findings have important implications for the study of local adaptation.
-
mercury bioaccumulation increases with latitude in a coastal marine fish atlantic silverside Menidia Menidia
Canadian Journal of Fisheries and Aquatic Sciences, 2017Co-Authors: Zofia Baumann, David O Conover, Celia Y Chen, Kate L Buckman, Nicholas S Fisher, Robert P Mason, Prentiss H Balcom, Hannes BaumannAbstract: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 partic...
-
pattern and scale of geographic variation in environmental sex determination in the atlantic silverside Menidia Menidia
Evolution, 2015Co-Authors: Lyndie A Hice, Tara A. Duffy, David O ConoverAbstract:The Atlantic silverside, Menidia Menidia (Pisces: Atherinidae), exhibits an exceptionally high level of clinal variation in sex determination across its geographic range. Previous work suggested linear changes in the level of temperature-dependent sex determination (TSD) with increasing latitude. Based on comparisons at 31 sites encompassing the entire species' range, we find that the change in level of TSD with latitude is instead highly nonlinear. The level of TSD is uniformly high in the south (Florida to New Jersey), then declines rapidly into the northern Gulf of Maine where genotypic sex determination (GSD) predominates and then rebounds to moderate levels of TSD in the northern-most populations of the Gulf of St. Lawrence. Major latitudinal breakpoints occur in central New Jersey (40(o)N) and the northern Gulf of Maine (44(o)N). No populations display pure TSD or GSD. Length of the growing season is the likely agent of selection driving variation in TSD with a threshold at 210 days. Because gene flow among populations is high, such distinct patterns of geographic variation in TSD/GSD are likely maintained by contemporary selection thereby demonstrating the adaptive fine tuning of sex determining mechanisms.
-
circulating levels of plasma igf i during recovery from size selective harvesting in Menidia Menidia
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2013Co-Authors: Tara A. Duffy, Matthew E. Picha, Russell J. Borski, David O ConoverAbstract:Abstract Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia Menidia were selected for size at age over multiple generations to mimic fisheries-induced selection. This selection regime produced three populations with significant differences in intrinsic growth rate. These growth differences partially rebounded, but persisted even after selection was relaxed, resulting in fast, intermediate, and slow-growing lines. Plasma IGF-1 was measured in these populations as a potential target of selection on growth. IGF-1 was significantly correlated with current length and mass, and was positively correlated with growth rate (g d −1 ) in two lines, indicating it may be an appropriate indicator of growth capacity. The slow-growing line exhibited higher overall IGF-1 levels relative to the depressed IGF-1 seen in the fast-growing line, contrary to our prediction. We offer possible explanations for this unusual pattern and argue that somatic growth is likely to be under control of mechanism(s) downstream to IGF-1. IGF-1 provides an interesting basis for understanding endocrine control of growth in response to artificial selection and recovery.
-
circulating levels of plasma igf i during recovery from size selective harvesting in Menidia Menidia part a molecular integrative physiology
Comparative Biochemistry and Physiology, 2013Co-Authors: Tara A. Duffy, Matthew E. Picha, Russell J. Borski, David O ConoverAbstract:Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia Menidia were selected for size at age over multiple generations to mimic fisheries-induced selection. This selection regime produced three populations with significant differences in intrinsic growth rate. These growth differences partially rebounded, but persisted even after selection was relaxed, resulting in fast, intermediate, and slow-growing lines. Plasma IGF-1 was measured in these populations as a potential target of selection on growth. IGF-1 was significantly correlated with current length and mass, and was positively correlated with growth rate (g d−1) in two lines, indicating it may be an appropriate indicator of growth capacity. The slow-growing line exhibited higher overall IGF-1 levels relative to the depressed IGF-1 seen in the fast-growing line, contrary to our prediction. We offer possible explanations for this unusual pattern and argue that somatic growth is likely to be under control of mechanism(s) downstream to IGF-1. IGF-1 provides an interesting basis for understanding endocrine control of growth in response to artificial selection and recovery.
Stephan B Munch - One of the best experts on this subject based on the ideXlab platform.
-
does reproductive investment decrease telomere length in Menidia Menidia
PLOS ONE, 2015Co-Authors: Jin Gao, Stephan B MunchAbstract:Given finite resources, intense investment in one life history trait is expected to reduce investment in others. Although telomere length appears to be strongly tied to age in many taxa, telomere maintenance requires energy. We therefore hypothesize that telomere maintenance may trade off against other life history characters. We used natural variation in laboratory populations of Atlantic silversides (Menidia Menidia) to study the relationship between growth, fecundity, life expectancy, and relative telomere length. In keeping with several other studies on fishes, we found no clear dependence of telomere length on age. However, we did find that more fecund fish tended to have both reduced life expectancy and shorter telomeres. This result is consistent with the hypothesis that there is a trade-off between telomere maintenance and reproductive output.
-
genetic and maternal variation in early growth in the atlantic silverside Menidia Menidia
Marine Ecology Progress Series, 2013Co-Authors: Jin Gao, Stephan B MunchAbstract:In the early life histories of many fish species, larger individuals have lower mortality rates and, as a consequence, growth is thought to be a primary determinant of recruitment. Although much is known about environmental influences on growth in the early life history, far less is known about genetic and maternal contributions. As the relative contributions of maternal, genetic, and environmental effects determine how populations respond to selective harvest, evaluating their magnitudes is an important step in constructing evolutionarily sustainable harvest strategies. Using Atlantic silversides Menidia Menidia as a model organism, we conducted a fullfactorial breeding study to measure maternal and genetic contributions to size at age through the first 2 wk of life. A total of 418 fulland half-sib families were raised in a common environment, and body lengths were recorded at 1, 5, 10, and 15 d post-hatch. Maximum likelihood was used to estimate the genetic and maternal variance components. Heritability for size at age was between 0.10 and 0.25, and increased with age. At hatch, non-genetic maternal contributions were ~7 times greater than the genetic contributions to size, but decreased with age. These significant genetic and maternal contributions to size at age indicate substantial potential to respond to selection, with subsequent population dynamic consequences.
-
high connectivity among locally adapted populations of a marine fish Menidia Menidia
Ecology, 2010Co-Authors: Lora M Clarke, Stephan B Munch, Simon R Thorrold, David O ConoverAbstract:Patterns of connectivity are important in understanding the geographic scale of local adaptation in marine populations. While natural selection can lead to local adaptation, high connectivity can diminish the potential for such adaptation to occur. Connectivity, defined as the exchange of individuals among subpopulations, is presumed to be significant in most marine species due to life histories that include widely dispersive stages. However, evidence of local adaptation in marine species, such the Atlantic silverside, Menidia Menidia, raises questions concerning the degree of connectivity. We examined geochemical signatures in the otoliths, or ear bones, of adult Atlantic silversides collected in 11 locations along the northeastern coast of the United States from New Jersey to Maine in 2004 and eight locations in 2005 using laser ablation inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratio monitoring mass spectrometry (irm-MS). These signatures were then compared to baseline signatures of juvenile fish of known origin to determine natal origin of these adult fish. We then estimated migration distances and the degree of mixing from these data. In both years, fish generally had the highest probability of originating from the same location in which they were captured (0.01-0.80), but evidence of mixing throughout the sample area was present. Furthermore, adult M. Menidia exhibit highly dispersive behavior with some fish migrating over 700 km. The probability of adult fish returning to natal areas differed between years, with the probability being, on average, 0.2 higher in the second year. These findings demonstrate that marine species with largely open populations are capable of local adaptation despite apparently high gene flow.
-
chemical signatures in the otoliths of a coastal marine fish Menidia Menidia from the northeastern united states spatial and temporal differences
Marine Ecology Progress Series, 2009Co-Authors: Stephan B Munch, Lora M Clarke, Benjamin D Walther, Simon R Thorrold, David O ConoverAbstract:Knowledge of population structure in marine systems is fundamental to effective management and conservation. The geochemical signature of otoliths may provide a promising natural tag for quantifying population structure in marine fishes. However, the spatial scale at which chemical signatures differ among species from different environments and with different life histories is not yet clear. We examined chemical signatures in the otoliths of juvenile Menidia Menidia, a ubiquitous nearshore marine species found along the east coast of North America that undergoes offshore winter migration. Specimens were collected from 16 locations in 2003 and from 9 locations in 2004 between New Jersey and Maine. Otolith geochemistry was analyzed using laser ablation inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry. Juvenile fish showed significant site-specific differences and were assigned to natal sites with 70% (2003) and 77% (2004) average cross-validated classification accuracies based on elemental (Mg, Mn, Sr, Ba, Cu, and Pb relative to Ca) and isotope (δ13C, δ18O) ratios using quadratic discriminant function analysis. Geochemical signatures showed significant interannual variation, suggesting natural tags are year-class specific. Results suggest enough heterogeneity exists in marine chemical signatures to track movements and determine whether M. Menidia return to their natal, nearshore location upon return from winter migration. Because M. Menidia show evidence of local adaptation, knowledge of this winter migration will have evolutionary and ecological implications. Geochemical signatures of otoliths will likely serve as a useful tool in species with similar life histories.
-
darwinian fishery science lessons from the atlantic silverside Menidia Menidia
Canadian Journal of Fisheries and Aquatic Sciences, 2005Co-Authors: David O Conover, Stephen A Arnott, Matthew R Walsh, Stephan B MunchAbstract: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 pro- cess 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 funda- mental questions in fishery science. Resume :On s'est peu interesse a la possibilite que la mortalite due a la peche puisse entrainer de rapides changements evolutifs dans le cycle biologique. En se concentrant seulement sur les effets ecologiques, la theorie et la pratique cou- rantes des peches presument implicitement ou bien que les influences genetiques sur le cycle biologique en nature sont negligeables ou alors que la selection naturelle et l'adaptation sont des processus lents qui peuvent en pratique etre ignores. Ces presuppositions ont pu se maintenir en l'absence de preuves contraires. En nous basant sur >25 ans de re- cherche sur la capucette, Menidia Menidia, nous demontrons que la variation genetique adaptative de plusieurs caracte- ristiques est finement ajustee a la variation naturelle du climat. Une partie importante de cette variation est causee par un gradient de mortalite hivernale reliee a la taille et implique des changements de l'ordre de deux ou trois fois dans les caracteristiques physiologiques qui influencent la productivite de la population. Il est maintenant connu que plu- sieurs autres especes possedent des patterns semblables. Des recoltes experimentales montrent que ces caracteristiques peuvent evoluer rapidement en reaction a la peche selective en fonction de la taille. Le pool des genotypes qui sont responsables des caracteristiques du cycle biologique forme donc une propriete tres dynamique des populations. Nous croyons que les lecons apprises chez Menidia s'appliquent a de nombreuses especes exploitees chez lesquelles des ob- servations similaires seraient difficiles a faire et nous suggerons une utilisation plus grande en sciences halieutiques des modeles de population qui s'interessent aux questions fondamentales. (Traduit par la Redaction) Conover et al. 737
Tara A. Duffy - One of the best experts on this subject based on the ideXlab platform.
-
pattern and scale of geographic variation in environmental sex determination in the atlantic silverside Menidia Menidia
Evolution, 2015Co-Authors: Lyndie A Hice, Tara A. Duffy, David O ConoverAbstract:The Atlantic silverside, Menidia Menidia (Pisces: Atherinidae), exhibits an exceptionally high level of clinal variation in sex determination across its geographic range. Previous work suggested linear changes in the level of temperature-dependent sex determination (TSD) with increasing latitude. Based on comparisons at 31 sites encompassing the entire species' range, we find that the change in level of TSD with latitude is instead highly nonlinear. The level of TSD is uniformly high in the south (Florida to New Jersey), then declines rapidly into the northern Gulf of Maine where genotypic sex determination (GSD) predominates and then rebounds to moderate levels of TSD in the northern-most populations of the Gulf of St. Lawrence. Major latitudinal breakpoints occur in central New Jersey (40(o)N) and the northern Gulf of Maine (44(o)N). No populations display pure TSD or GSD. Length of the growing season is the likely agent of selection driving variation in TSD with a threshold at 210 days. Because gene flow among populations is high, such distinct patterns of geographic variation in TSD/GSD are likely maintained by contemporary selection thereby demonstrating the adaptive fine tuning of sex determining mechanisms.
-
circulating levels of plasma igf i during recovery from size selective harvesting in Menidia Menidia
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2013Co-Authors: Tara A. Duffy, Matthew E. Picha, Russell J. Borski, David O ConoverAbstract:Abstract Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia Menidia were selected for size at age over multiple generations to mimic fisheries-induced selection. This selection regime produced three populations with significant differences in intrinsic growth rate. These growth differences partially rebounded, but persisted even after selection was relaxed, resulting in fast, intermediate, and slow-growing lines. Plasma IGF-1 was measured in these populations as a potential target of selection on growth. IGF-1 was significantly correlated with current length and mass, and was positively correlated with growth rate (g d −1 ) in two lines, indicating it may be an appropriate indicator of growth capacity. The slow-growing line exhibited higher overall IGF-1 levels relative to the depressed IGF-1 seen in the fast-growing line, contrary to our prediction. We offer possible explanations for this unusual pattern and argue that somatic growth is likely to be under control of mechanism(s) downstream to IGF-1. IGF-1 provides an interesting basis for understanding endocrine control of growth in response to artificial selection and recovery.
-
circulating levels of plasma igf i during recovery from size selective harvesting in Menidia Menidia part a molecular integrative physiology
Comparative Biochemistry and Physiology, 2013Co-Authors: Tara A. Duffy, Matthew E. Picha, Russell J. Borski, David O ConoverAbstract:Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia Menidia were selected for size at age over multiple generations to mimic fisheries-induced selection. This selection regime produced three populations with significant differences in intrinsic growth rate. These growth differences partially rebounded, but persisted even after selection was relaxed, resulting in fast, intermediate, and slow-growing lines. Plasma IGF-1 was measured in these populations as a potential target of selection on growth. IGF-1 was significantly correlated with current length and mass, and was positively correlated with growth rate (g d−1) in two lines, indicating it may be an appropriate indicator of growth capacity. The slow-growing line exhibited higher overall IGF-1 levels relative to the depressed IGF-1 seen in the fast-growing line, contrary to our prediction. We offer possible explanations for this unusual pattern and argue that somatic growth is likely to be under control of mechanism(s) downstream to IGF-1. IGF-1 provides an interesting basis for understanding endocrine control of growth in response to artificial selection and recovery.
-
regional differentiation and post glacial expansion of the atlantic silverside Menidia Menidia an annual fish with high dispersal potential
Marine Biology, 2011Co-Authors: Megan E Mach, David O Conover, Tara A. Duffy, Lyndie A Hice, Elizabeth J Sbrocco, Paul H BarberAbstract:The coastal marine environment of the Northwest Atlantic contains strong environmental gradients that create distinct marine biogeographic provinces by limiting dispersal, recruitment, and survival. This region has also been subjected to numerous Pleistocene glacial cycles, resulting in repeated extirpations and recolonizations in northern populations of marine organisms. In this study, we examined patterns of genetic structure and historical demography in the Atlantic silverside, Menidia Menidia, an annual marine fish with high dispersal potential but with well-documented patterns of clinal phenotypic adaptation along the environmental gradients of the Northwest Atlantic. Contrary to previous studies indicating genetic homogeneity that should preclude regional adaptation, results demonstrate subtle but significant (FST = 0.07; P < 0.0001) genetic structure among three phylogeographic regions that partially correspond with biogeographic provinces, suggesting regional limits to gene flow. Tests for non-equilibrium population dynamics and latitudinal patterns in genetic diversity indicate northward population expansion from a single southern refugium following the last glacial maximum, suggesting that phylogeographic and phenotypic patterns have relatively recent origins. The recovery of phylogeographic structure and the partial correspondence of these regions to recognized biogeographic provinces suggest that the environmental gradients that shape biogeographic patterns in the Northwest Atlantic may also limit gene flow in M. Menidia, creating phylogeographic structure and contributing to the creation of latitudinal phenotypic clines in this species.
-
Ontogenesis of gonadal aromatase gene expression in atlantic silverside (Menidia Menidia) populations with genetic and temperature-dependent sex determination.
Journal of experimental zoology. Part A Ecological genetics and physiology, 2010Co-Authors: Tara A. Duffy, Matthew E. Picha, Eugene T. Won, Russell J. Borski, Anne E. Mcelroy, David O ConoverAbstract:Cytochrome P450 aromatase (P450arom), an enzyme that converts testosterone to 17b-estradiol, is an important mediator of sex determination in teleosts with genetic sex determination (GSD) and temperature-dependent sex determination (TSD). We compared the ontogenetic expression of P450arom in two populations of Atlantic silversides, Menidia Menidia, which exhibit TSD (South Carolina) or GSD (Nova Scotia, Canada) using quantitative, real-time polymerase chain reaction (qRT-PCR). Embryos and newly hatched larvae were reared at an intermediate sex ratio-producing temperature (211C), and older larvae and juveniles were reared at temperatures that feminize (151C) and masculinize (281C) to assess the temperature response of P450arom during development. Before sex determination, embryos and newly-hatched larvae displayed negligible P450arom expression, indicating minimal upregulation of this gene before sex determination. Gene expression increased in both populations during sex differentiation. Nova Scotia fish with GSD exhibited presumptive male- and female-like expression levels during early sex differentiation that were not influenced by temperature. South Carolina fish displayed low levels of expression at 28 o C with significantly heightened expression in some individuals at 151C, indicating that P450arom is temperature sensitive in the population with TSD. Populations also differed in the timing and maximal levels of P450arom expression, with fish from Nova Scotia exhibiting both the highest and earliest increase in expression in presumptive females. Our results support the hypothesis that P450arom is involved in female sex differentiation in this species, but is only responsive to temperature in M. Menidia populations that exhibit TSD. J. Exp. Zool. 313A:421–431, 2010. & 2010 Wiley-Liss, Inc. How to cite this article: Duffy TA, Picha ME, Won ET, Borski RJ, McElroy AE, Conover DO. 2010. Ontogenesis of gonadal aromatase gene expression in Atlantic silverside (Menidia Menidia) populations with genetic and temperature-dependent sex determination. J. Exp. Zool. 313A:421–431.
Hannes Baumann - One of the best experts on this subject based on the ideXlab platform.
-
a comprehensive non redundant reference transcriptome for the atlantic silverside Menidia Menidia
Marine Genomics, 2020Co-Authors: Nina Overgaard Therkildsen, Hannes BaumannAbstract:The Atlantic silverside (Menidia Menidia) has been the focus of extensive research efforts in ecology, evolutionary biology, and physiology over the past three decades, but lack of genomic resources has so far hindered examination of the molecular basis underlying the remarkable patterns of phenotypic variation described in this species. We here present the first reference transcriptome for M. Menidia. We sought to capture a single representative sequence from as many genes as possible by first using a combination of Trinity and the CLC Genomics Workbench to de novo assemble contigs based on RNA-seq data from multiple individuals, tissue types, and life stages. To reduce redundancy, we passed the combined raw assemblies through a stringent filtering pipeline based both on sequence similarity to related species and computational predictions of transcript quality, condensing an initial set of >480,000 contigs to a final set of 20,998 representative contigs, amounting to a total length of 53.3 Mb. In this final assembly, 91% of the contigs were functionally annotated with putative gene function and gene ontology (GO) terms and/or InterProScan identifiers. The assembly contains complete or nearly complete copies of >95% of 248 highly conserved core genes present in low copy number across higher eukaryotes, and partial copies of another 3.8%, suggesting that our assembly provides relatively comprehensive coverage of the M. Menidia transcriptome. The assembly provided here will be an important resource for future research.
-
acidification and hypoxia interactively affect metabolism in embryos but not larvae of the coastal forage fish Menidia Menidia
The Journal of Experimental Biology, 2020Co-Authors: T G Schwemmer, Hannes Baumann, Christopher S Murray, A I Molina, Janet A NyeAbstract:Ocean acidification is occurring in conjunction with warming and deoxygenation as a result of anthropogenic greenhouse gas emissions. Multistressor experiments are critically needed to better understand the sensitivity of marine organisms to these concurrent changes. Growth and survival responses to acidification have been documented for many marine species, but studies that explore underlying physiological mechanisms of carbon dioxide (CO2) sensitivity are less common. We investigated oxygen consumption rates as proxies for metabolic responses in embryos and newly hatched larvae of an estuarine forage fish (Atlantic silverside, Menidia Menidia) to factorial combinations of CO2×temperature or CO2×oxygen. Metabolic rates of embryos and larvae significantly increased with temperature, but partial pressure of CO2 (PCO2) alone did not affect metabolic rates in any experiment. However, there was a significant interaction between PCO2 and partial pressure of oxygen (PO2) in embryos, because metabolic rates were unaffected by PO2 level at ambient PCO2, but decreased with declining PO2 under elevated PCO2. For larvae, however, PCO2 and PO2 had no significant effect on metabolic rates. Our findings suggest high individual variability in metabolic responses to high PCO2, perhaps due to parental effects and time of spawning. We conclude that early life metabolism is largely resilient to elevated PCO2 in this species, but that acidification likely influences energetic responses and thus vulnerability to hypoxia.
-
starvation rates in larval and juvenile atlantic silversides Menidia Menidia are unaffected by high co2 conditions
Marine Biology, 2018Co-Authors: Hannes Baumann, Elle M Parks, Christopher S MurrayAbstract:Over the past decade, laboratory experiments on fish early life stages have found many traits that are evidently sensitive to elevated CO2 levels. With respect to larval growth, high CO2 environments are commonly assumed to increase acid–base regulation and other plastic responses, thus incurring additional metabolic costs that reduce the scope for growth. This assumption is not well supported by empirical evidence. One reason might be that experiments often provide unrestricted feeding conditions, which could allow larvae to compensate for higher costs by increased food intake. To remove potentially confounding effects of larval feeding, we conducted a series of starvation trials on offspring of the Atlantic silverside (Menidia Menidia), predicting faster starvation at high compared to ambient CO2 treatments. We compiled observations from five separate experiments spanning different years, laboratories, temperatures (17–26 °C), life stages (newly hatched larvae, previously fed larvae, early juveniles), and CO2 levels (300–6500 µatm). Contrary to expectation, we found that starvation rates were largely independent of the CO2 environment in this fish species. The one exception occurred at the lowest temperature and most extreme CO2 treatment, which resulted in slower not faster starvation in newly hatched larvae at high compared to ambient CO2 treatments. The apparent failure of starvation rate as a proxy for CO2 effects on larval fish metabolism may have several reasons, including potential CO2 tolerance of offspring, observed large stochasticity in early life survival masking small metabolic costs of high CO2, and the general depression and reconfiguration of fish metabolism in response to food deprivation.
-
potential for maternal effects on offspring co2 sensitivities in the atlantic silverside Menidia Menidia
Journal of Experimental Marine Biology and Ecology, 2018Co-Authors: Jacob T Snyder, Christopher S Murray, Hannes BaumannAbstract:Abstract For marine fish, the influence of maternal provisioning on offspring sensitivity to high carbon dioxide (CO2) conditions remains unknown. We separately reared offspring obtained from five wild-caught Atlantic silverside ( Menidia Menidia ) females from fertilization to 16 days post hatch under contrasting CO2 conditions (ambient: ~ 400 μatm, acidified: ~ 2,300 μatm), testing whether average survival during the embryo and larval stage, hatch length, final length, and growth rates were affected by CO2, female identity, or their interaction. Average trait responses did not significantly differ between treatments (CO2 or female identity), however, significant CO2 × female identity interactions indicated that females produced offspring with different average CO2 sensitivities. We then examined whether differential egg provisioning with fatty acids (FA) may partially explain the observed differences in offspring CO2 sensitivities. Concentrations of 27 FAs in the unfertilized eggs of each female were measured. Cumulative absolute FA levels were negatively related to hatch length and to the log-transformed CO2 response ratio of hatch length. Eggs with lower concentrations of 20:1n9 and 22:5n3 resulted in offspring where embryo survival was negatively impacted by high CO2. Eggs with higher concentrations of 18:3n3, 18:4n3, and 22:6n3 produced shorter offspring at hatching under high CO2 conditions. These results indicate that maternal provisioning might be an additional determinant of CO2 sensitivity in fish early life stages. Acidification experiments should therefore utilize large numbers of parents from different natural conditions and, where possible, track heritage.
-
mercury bioaccumulation increases with latitude in a coastal marine fish atlantic silverside Menidia Menidia
Canadian Journal of Fisheries and Aquatic Sciences, 2017Co-Authors: Zofia Baumann, David O Conover, Celia Y Chen, Kate L Buckman, Nicholas S Fisher, Robert P Mason, Prentiss H Balcom, Hannes BaumannAbstract: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 partic...
Gilberto Contrerasrivero - One of the best experts on this subject based on the ideXlab platform.
-
crecimiento y mortalidad del charal Menidia jordani en el estanque guillermo lagunes gl estado de mexico
Revista Chapingo Serie Ciencias Forestales Y Del Ambiente, 2011Co-Authors: N A Navarretesalgado, Gilberto ContrerasriveroAbstract:Resumen es: En este estudio se evaluo el crecimiento con el modelo de Von Bertalanffy y la mortalidad del charal Menidia jordani, en el estanque de cultivo Guillermo...
-
situacion de Menidia jordani pisces atherinopsidae en el embalse la goleta estado de mexico
Revista Chapingo Serie Ciencias Forestales Y Del Ambiente, 2010Co-Authors: N A Navarretesalgado, Gilberto Contrerasrivero, D L JacoboseguraAbstract:Resumen es: En este estudio se analiza la situacion del charal Menidia jordani (Pisces, Atherinopsidae) en el embalse La Goleta, Estado de Mexico y las variaciones p...