scholarly journals Ecological ramifications of adaptation to size-selective mortality

2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Charlotte Evangelista ◽  
Julia Dupeu ◽  
Joakim Sandkjenn ◽  
Beatriz Diaz Pauli ◽  
Anders Herland ◽  
...  
Keyword(s):  
Somatic Growth ◽  
Benthic Algae ◽  
Diet Breadth ◽  
Fish Density ◽  
Ecosystem Functions ◽  
Selective Mortality ◽  
Fish Introduction ◽  
Early Maturity ◽  
Algae Biomass ◽  
Evolutionary Response

Size-selective mortality due to harvesting is a threat to numerous exploited species, but how it affects the ecosystem remains largely unexplored. Here, we used a pond mesocosm experiment to assess how evolutionary responses to opposite size-selective mortality interacted with the environment (fish density and light intensity used as a proxy of resource availability) to modulate fish populations, prey community composition and ecosystem functions. We used medaka ( Oryzias latipes ) previously selected over 10 generations for small size (harvest-like selection; small-breeder line) or large size (large-breeder line), which displayed slow somatic growth and early maturity or fast somatic growth and late maturity, respectively. Large-breeder medaka produced more juveniles, which seemed to grow faster than small-breeder ones but only under high fish density. Additionally, large-breeder medaka had an increased impact on some benthic prey, suggesting expanded diet breadth and/or enhanced foraging abilities. As a consequence, increased light stimulated benthic algae biomass only in presence of large-breeder medaka, which were presumably better at controlling benthic grazers. Aggregated effect sizes at the community and ecosystem levels revealed that the ecological effects of medaka evolution were of similar magnitude to those induced by the environment and fish introduction. These findings indicate the important environmental dependency of evolutionary response to opposite size-selective mortality on higher levels of biological organizations.

scholarly journals Winter wren populations show adaptation to local climate

2016 ◽  
Vol 3 (6) ◽  
pp. 160250 ◽  
Author(s):  
Catriona A. Morrison ◽  
Robert A. Robinson ◽  
James W. Pearce-Higgins
Keyword(s):  
Climate Change ◽  
Body Size ◽  
Local Adaptation ◽  
Time Lag ◽  
Climate Change Impacts ◽  
Extreme Weather Events ◽  
Evolutionary Adaptation ◽  
Selective Mortality ◽  
Local Climate ◽  
Evolutionary Response

Most studies of evolutionary responses to climate change have focused on phenological responses to warming, and provide only weak evidence for evolutionary adaptation. This could be because phenological changes are more weakly linked to fitness than more direct mechanisms of climate change impacts, such as selective mortality during extreme weather events which have immediate fitness consequences for the individuals involved. Studies examining these other mechanisms may be more likely to show evidence for evolutionary adaptation. To test this, we quantify regional population responses of a small resident passerine (winter wren Troglodytes troglodytes ) to a measure of winter severity (number of frost days). Annual population growth rate was consistently negatively correlated with this measure, but the point at which different populations achieved stability ( λ  = 1) varied across regions and was closely correlated with the historic average number of frost days, providing strong evidence for local adaptation. Despite this, regional variation in abundance remained negatively related to the regional mean number of winter frost days, potentially as a result of a time-lag in the rate of evolutionary response to climate change. As expected from Bergmann's rule, individual wrens were heavier in colder regions, suggesting that local adaptation may be mediated through body size. However, there was no evidence for selective mortality of small individuals in cold years, with annual variation in mean body size uncorrelated with the number of winter frost days, so the extent to which local adaptation occurs through changes in body size, or another mechanism remains uncertain.

scholarly journals Evolutionary response to size-selective mortality in an exploited fish population

2007 ◽  
Vol 274 (1613) ◽  
pp. 1015-1022 ◽  
Author(s):  
Douglas P Swain ◽  
Alan F Sinclair ◽  
J Mark Hanson
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Population ◽  
Fish Populations ◽  
Selective Mortality ◽  
Genetic Changes ◽  
Evolutionary Response ◽  
In The Wild ◽  
Size At Age ◽  
Change In Mean

Many collapsed fish populations have failed to recover after a decade or more with little fishing. This may reflect evolutionary change in response to the highly selective mortality imposed by fisheries. Recent experimental work has demonstrated a rapid genetic change in growth rate in response to size-selective harvesting of laboratory fish populations. Here, we use a 30-year time-series of back-calculated lengths-at-age to test for a genetic response to size-selective mortality in the wild in a heavily exploited population of Atlantic cod ( Gadus morhua ). Controlling for the effects of density- and temperature-dependent growth, the change in mean length of 4-year-old cod between offspring and their parental cohorts was positively correlated with the estimated selection differential experienced by the parental cohorts between this age and spawning. This result supports the hypothesis that there have been genetic changes in growth in this population in response to size-selective fishing. Such changes may account for the continued small size-at-age in this population despite good conditions for growth and little fishing for over a decade. This study highlights the need for management regimes that take into account the evolutionary consequences of fishing.

scholarly journals Alien Fish Species in the Mbô Floodplain Rivers in Cameroon

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Claudine Tekounegning Tiogué ◽  
David Nguenga ◽  
Minette Eyango Tomedi-Tabi ◽  
Joseph Tekwombuo ◽  
Guegang Tekou ◽  
...  
Keyword(s):  
Fish Species ◽  
Clarias Gariepinus ◽  
Somatic Growth ◽  
Seasonal Fluctuation ◽  
Fish Introduction ◽  
Alien Fish ◽  
Traditional Fishing ◽  
Number Of Individuals ◽  
Floodplain Rivers ◽  
Alien Fish Species

The aim of this study was to identify different alien fish species introduced in the Mbô Floodplain (MF) Rivers in Cameroon and to study their life-history traits. For this purpose, a total number of 237 fishes with a total length (TL) of 24.50 ± 5.97 cm and total weight of 199.50 ± 106.78 g collected by traditional fishing gears were used for taxonomic identification. Four species grouped into three families were identified: Clariidae (Clarias gariepinus), Cichlidae (Oreochromis niloticus and Tilapia cameronensis), and Channidae (Parachanna obscura). There are two types of fish introduction: accidental introduction and intentional transfer. All fish species collected and examined were of large sizes (TL > 25 cm). The regression coefficient b of the length-weight relationship ranged from 3.00 (C. gariepinus) to 3.37 (T. cameronensis) (3.18 ± 0.17). Fish species showed a monthly and seasonal fluctuation in abundance in number of individuals. Alien fish species in the Mbô Floodplain showed two types of somatic growth: isometric and positive allometric. 75% of overall alien fish species were established and they recorded a mean K factor of 0.70 ± 0.40. Only 25.00% of the sampled species had more females than males.

scholarly journals Why Do We Need to Document and Conserve Foundation Species in Freshwater Wetlands?

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 265 ◽  
Author(s):  
Luca Marazzi ◽  
Evelyn Gaiser ◽  
Maarten Eppinga ◽  
Jay Sah ◽  
Lu Zhai ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Benthic Algae ◽  
Freshwater Wetlands ◽  
Foundation Species ◽  
Ecosystem Functions ◽  
Wetland Ecosystems ◽  
Bald Cypress ◽  
Primary Producer

Foundation species provide habitat to other organisms and enhance ecosystem functions, such as nutrient cycling, carbon storage and sequestration, and erosion control. We focus on freshwater wetlands because these ecosystems are often characterized by foundation species; eutrophication and other environmental changes may cause the loss of some of these species, thus severely damaging wetland ecosystems. To better understand how wetland primary producer foundation species support other species and ecosystem functions across environmental gradients, we reviewed ~150 studies in subtropical, boreal, and temperate freshwater wetlands. We look at how the relative dominance of conspicuous and well-documented species (i.e., sawgrass, benthic diatoms and cyanobacteria, Sphagnum mosses, and bald cypress) and the foundational roles they play interact with hydrology, nutrient availability, and exposure to fire and salinity in representative wetlands. Based on the evidence analyzed, we argue that the foundation species concept should be more broadly applied to include organisms that regulate ecosystems at different spatial scales, notably the microscopic benthic algae that critically support associated communities and mediate freshwater wetlands’ ecosystem functioning. We give recommendations on how further research efforts can be prioritized to best inform the conservation of foundation species and of the freshwater wetlands they support.

scholarly journals Does anthropogenic introduction of guppy fish (Poecilia reticulata) impact faunal species diversity and abundance in natural aquatic habitats? A systematic review protocol

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Misaki Sasanami ◽  
John Hustedt ◽  
Neal Alexander ◽  
Olaf Horstick ◽  
Leigh Bowman ◽  
...  
Keyword(s):  
Species Diversity ◽  
Poecilia Reticulata ◽  
Tropical Fish ◽  
Food Sources ◽  
Ecosystem Functions ◽  
Sufficient Evidence ◽  
Aquatic Habitats ◽  
Fish Introduction ◽  
Scientific Review ◽  
Guppy Fish

Abstract Background The guppy fish (Poecilia reticulata) is a tropical fish ancestrally linked to northern South America and the Caribbean. It is known to be very tolerant of and adaptable to new environments, and able to consume multiple food sources, including mosquito larvae. Consequently, guppies have been frequently introduced to non-native ecosystems to control mosquito populations, resulting in near-global distribution. Indeed, due to the increasing need for mosquito-borne disease control, guppy releases will likely continue, however there are concerns about potential adverse impacts on other species, biodiversity, and certain ecosystem functions. The most significant of these is local species extinction, and by extension, reduced biodiversity. Yet, the extent of these impacts has not been evaluated by scientific review. Accordingly, this study will examine and evaluate whether anthropogenic introduction of guppy fish (Poecilia reticulata) has impacts on faunal species diversity and abundance in natural aquatic habitats. The results of this review may have implications for environmental management and policy and inform ecosystem-based integrated vector management and public health policy. Methods Relevant scientific articles will be identified by searching electronic databases. Articles will be included if they report changes or differences, associated with guppy fish introduction, in at least one of these population parameters: (1) abundance of individuals in any species, (2) total abundance of individuals in all species present, (3) species richness, (4) species diversity, and (5) community evenness. Each article will be assessed by at least two independent reviewers against pre-defined inclusion/exclusion criteria. Snowballing reference lists of included articles will be conducted. At least two reviewers will critically appraise all included studies using the Collaboration for Environmental Evidence Critical Appraisal Tool (CEECAT) and any discrepancies will be resolved by discussion between the two or adjudication by a third author if agreement is not reached. Each study will also be subjected to data extraction against pre-defined qualitative and quantitative outcomes and results will be tabulated/presented in figures where appropriate. A meta-analysis will be carried out on outcome parameters with sufficient evidence.

scholarly journals Empirical evidence of plasticity in life-history characteristics across climatic and fish density gradients

2017 ◽  
Vol 74 (4) ◽  
pp. 464-474 ◽  
Author(s):  
Hillary G.M. Ward ◽  
John R. Post ◽  
Nigel P. Lester ◽  
Paul J. Askey ◽  
Theresa Godin
Keyword(s):  
Life History ◽  
Empirical Evidence ◽  
Growth Rates ◽  
Life History Theory ◽  
Resource Competition ◽  
Somatic Growth ◽  
Life History Strategies ◽  
Fish Density ◽  
Density Gradients ◽  
Life History Characteristics

Understanding how environmental productivity and resource competition influence somatic growth rates and plasticity in life-history traits is a critical component of population ecology. However, evolutionary effects often confound the relationship between plasticity in life-history characteristics and environmental productivity. We used a unique set of experimentally stocked populations of rainbow trout (Oncorhynchus mykiss) to empirically test predictions from life-history theory relating to patterns in immature growth rates, age- and size-at-maturity, and the energy allocated into reproduction across climatic and fish density gradients. Our results support theoretical predictions that plasticity in life-history characteristics is a function of environmental variables. In particular, we demonstrate that immature growth rates are best explained by climatic and density-dependent competition effects and that age-at-maturity and the energy allocated to reproduction depends on juvenile growth conditions. Empirical evidence of these relationships helps to improve our understanding of optimal life-history strategies of fish populations.

Review of Somatic Growth of the Child.

1967 ◽  
Vol 12 (7) ◽  
pp. 382-383
Author(s):  
HOWARD V. MEREDITH
Keyword(s):  
Somatic Growth

Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

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