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1.
PLoS One ; 17(7): e0271043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35877762

RESUMO

Video monitoring is a rapidly evolving tool in aquatic ecological research because of its non-destructive ability to assess fish assemblages. Nevertheless, methodological considerations of video monitoring techniques are often overlooked, especially in more complex sampling designs, causing inefficient data collection, processing, and interpretation. In this study, we discuss how video transect sampling designs could be assessed and how the inter-observer variability, design errors and sampling variability should be quantified and accounted for. The study took place in the coastal areas of the Galapagos archipelago and consisted of a hierarchical repeated-observations sampling design with multiple observers. Although observer bias was negligible for the assessment of fish assemblage structure, diversity and counts of individual species, sampling variability caused by simple counting/detection errors, observer effects and instantaneous fish displacement was often important. Especially for the counts of individual species, sampling variability most often exceeded the variability of the transects and sites. An extensive part of the variability in the fish assemblage structure was explained by the different transects (13%), suggesting that a sufficiently high number of transects is required to account for the within-location variability. Longer transect lengths allowed a better representation of the fish assemblages as sampling variability decreased by 33% if transect length was increased from 10 to 50 meters. However, to increase precision, including more repeats was typically more efficient than using longer transect lengths. The results confirm the suitability of the technique to study reef fish assemblages, but also highlight the importance of a sound methodological assessment since different biological responses and sampling designs are associated with different levels of sampling variability, precision and ecological relevance. Therefore, besides the direct usefulness of the results, the procedures to establish them may be just as valuable for researchers aiming to optimize their own sampling technique and design.


Assuntos
Biodiversidade , Peixes , Animais , Ecossistema , Peixes/fisiologia , Viés de Seleção
2.
PLoS One ; 17(7): e0265103, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35834446

RESUMO

Daphnia, an ecologically important zooplankton species in lakes, shows both genetic adaptation and phenotypic plasticity in response to temperature and fish predation, but little is known about the molecular basis of these responses and their potential interactions. We performed a factorial experiment exposing laboratory-propagated Daphnia pulicaria clones from two lakes in the Sierra Nevada mountains of California to normal or high temperature (15°C or 25°C) in the presence or absence of fish kairomones, then measured changes in life history and gene expression. Exposure to kairomones increased upper thermal tolerance limits for physiological activity in both clones. Cloned individuals matured at a younger age in response to higher temperature and kairomones, while size at maturity, fecundity and population intrinsic growth were only affected by temperature. At the molecular level, both clones expressed more genes differently in response to temperature than predation, but specific genes involved in metabolic, cellular, and genetic processes responded differently between the two clones. Although gene expression differed more between clones from different lakes than experimental treatments, similar phenotypic responses to predation risk and warming arose from these clone-specific patterns. Our results suggest that phenotypic plasticity responses to temperature and kairomones interact synergistically, with exposure to fish predators increasing the tolerance of Daphnia pulicaria to stressful temperatures, and that similar phenotypic responses to temperature and predator cues can be produced by divergent patterns of gene regulation.


Assuntos
Daphnia , Pulicaria , Animais , Daphnia/fisiologia , Peixes/fisiologia , Feromônios/farmacologia , Comportamento Predatório/fisiologia , Temperatura
3.
J Fish Biol ; 101(1): 3, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35852476
4.
Biol Psychol ; 172: 108382, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35777519

RESUMO

Mammals show clear changes in heart rate linked to lung ventilation, characterized as respiratory sinus arrhythmia (RSA). These changes are controlled in part by variations in the level of inhibitory control exerted on the heart by the parasympathetic arm of the autonomic nervous system (PNS). This originates from preganglionic neurons in the nucleus ambiguous that supply phasic, respiration-related activity to the cardiac branch of the vagus nerve, via myelinated, efferent fibres with rapid conduction velocities. An elaboration of these central mechanisms, under the control of a 'vagal system' has been endowed by psychologists with multiple functions concerned with 'social engagement' in mammals and, in particular, humans. Long-term study of cardiorespiratory interactions (CRI) in other major groups of vertebrates has established that they all show both tonic and phasic control of heart rate, imposed by the PNS. This derives centrally from neurones located in variously distributed nuclei, supplying the heart via fast-conducting, myelinated, efferent fibres. Water-breathing vertebrates, which include fishes and larval amphibians, typically show direct, 1:1 CRI between heart beats and gill ventilation, controlled from the dorsal vagal motor nucleus. In air-breathing, ectothermic vertebrates, including reptiles, amphibians and lungfish, CRI mirroring RSA have been shown to improve oxygen uptake during phasic ventilation by changes in perfusion of their respiratory organs, due to shunting of blood over across their undivided hearts. This system may constitute the evolutionary basis of that generating RSA in mammals, which now lacks a major physiological role in respiratory gas exchange, due to their completely divided systemic and pulmonary circulations.


Assuntos
Sistema Nervoso Autônomo , Vertebrados , Animais , Arritmia Sinusal , Sistema Nervoso Autônomo/fisiologia , Peixes/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Mamíferos , Filogenia , Respiração , Nervo Vago/fisiologia , Vertebrados/fisiologia
5.
Elife ; 112022 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-35852826

RESUMO

Predation is one of the main evolutionary drivers of social grouping. While it is well appreciated that predation risk is likely not shared equally among individuals within groups, its detailed quantification has remained difficult due to the speed of attacks and the highly dynamic nature of collective prey response. Here, using high-resolution tracking of solitary predators (Northern pike) hunting schooling fish (golden shiners), we not only provide insights into predator decision-making, but show which key spatial and kinematic features of predator and prey predict the risk of individuals to be targeted and to survive attacks. We found that pike tended to stealthily approach the largest groups, and were often already inside the school when launching their attack, making prey in this frontal 'strike zone' the most vulnerable to be targeted. From the prey's perspective, those fish in central locations, but relatively far from, and less aligned with, neighbours, were most likely to be targeted. While the majority of attacks were successful (70%), targeted individuals that did manage to avoid being captured exhibited a higher maximum acceleration response just before the attack and were further away from the pike's head. Our results highlight the crucial interplay between predators' attack strategy and response of prey underlying the predation risk within mobile animal groups.


Assuntos
Peixes , Comportamento Predatório , Animais , Peixes/fisiologia , Comportamento Predatório/fisiologia
6.
Elife ; 112022 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-35880746

RESUMO

A crucial evolutionary change in vertebrate history was the Palaeozoic (Devonian 419-359 million years ago) water-to-land transition, allowed by key morphological and physiological modifications including the acquisition of lungs. Nonetheless, the origin and early evolution of vertebrate lungs remain highly controversial, particularly whether the ancestral state was paired or unpaired. Due to the rarity of fossil soft tissue preservation, lung evolution can only be traced based on the extant phylogenetic bracket. Here we investigate, for the first time, lung morphology in extensive developmental series of key living lunged osteichthyans using synchrotron x-ray microtomography and histology. Our results shed light on the primitive state of vertebrate lungs as unpaired, evolving to be truly paired in the lineage towards the tetrapods. The water-to-land transition confronted profound physiological challenges and paired lungs were decisive for increasing the surface area and the pulmonary compliance and volume, especially during the air-breathing on land.


All life on Earth started out under water. However, around 400 million years ago some vertebrates, such as fish, started developing limbs and other characteristics that allowed them to explore life on land. One of the most pivotal features to evolve was the lungs, which gave vertebrates the ability to breathe above water. Most land-living vertebrates, including humans, have two lungs which sit on either side of their chest. The lungs extract oxygen from the atmosphere and transfer it to the bloodstream in exchange for carbon dioxide which then gets exhaled out in to the atmosphere. How this important organ first evolved is a hotly debated topic. This is largely because lung tissue does not preserve well in fossils, making it difficult to trace how the lungs of vertebrates changed over the course of evolution. To overcome this barrier, Cupello et al. compared the lungs of living species which are crucial to understand the early stages of the water-to-land transition. This included four species of lunged bony fish which breathe air at the water surface, and a four-legged salamander that lives on land. Cupello et al. used a range of techniques to examine how the lungs of the bony fish and salamander changed shape during development. The results suggested that the lungs of vertebrates started out as a single organ, which became truly paired later in evolution once vertebrates started developing limbs. This anatomical shift increased the surface area available for exchanging oxygen and carbon dioxide so that vertebrates could breathe more easily on land. These findings provide new insights in to how the lung evolved into the paired structure found in most vertebrates alive today. It likely that this transition allowed vertebrates to fully adapt to breathing above water, which may explain why this event only happened once over the course of evolution.


Assuntos
Evolução Biológica , Água , Animais , Peixes/fisiologia , Fósseis , Pulmão , Filogenia , Vertebrados
7.
Proc Natl Acad Sci U S A ; 119(31): e2119828119, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35881791

RESUMO

Diversity of feeding mechanisms is a hallmark of reef fishes, but the history of this variation is not fully understood. Here, we explore the emergence and proliferation of a biting mode of feeding, which enables fishes to feed on attached benthic prey. We find that feeding modes other than suction, including biting, ram biting, and an intermediate group that uses both biting and suction, were nearly absent among the lineages of teleost fishes inhabiting reefs prior to the end-Cretaceous mass extinction, but benthic biting has rapidly increased in frequency since then, accounting for about 40% of reef species today. Further, we measured the impact of feeding mode on body shape diversification in reef fishes. We fit a model of multivariate character evolution to a dataset comprising three-dimensional body shape of 1,530 species of teleost reef fishes across 111 families. Dedicated biters have accumulated over half of the body shape variation that suction feeders have in just 18% of the evolutionary time by evolving body shape ∼1.7 times faster than suction feeders. As a possible response to the ecological and functional diversity of attached prey, biters have dynamically evolved both into shapes that resemble suction feeders as well as novel body forms characterized by lateral compression and small jaws. The ascendance of species that use biting mechanisms to feed on attached prey reshaped modern reef fish assemblages and has been a major contributor to their ecological and phenotypic diversification.


Assuntos
Peixes , Somatotipos , Animais , Recifes de Corais , Extinção Biológica , Peixes/fisiologia , Masculino , Ovinos
8.
Front Neural Circuits ; 16: 895381, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35874430

RESUMO

The ability to navigate in the world is crucial to many species. One of the most fundamental unresolved issues in understanding animal navigation is how the brain represents spatial information. Although navigation has been studied extensively in many taxa, the key efforts to determine the neural basis of navigation have focused on mammals, usually in lab experiments, where the allocated space is typically very small; e.g., up to one order of magnitude the size of the animal, is limited by artificial walls, and contains only a few objects. This type of setting is vastly different from the habitat of animals in the wild, which is open in many cases and is virtually limitless in size compared to its inhabitants. Thus, a fundamental open question in animal navigation is whether small-scale, spatially confined, and artificially crafted lab experiments indeed reveal how navigation is enacted in the real world. This question is difficult to study given the technical problems associated with in vivo electrophysiology in natural settings. Here, we argue that these difficulties can be overcome by implementing state of the art technology when studying the rivulated rabbitfish, Siganus rivulatus as the model animal. As a first step toward this goal, using acoustic tracking of the reef, we demonstrate that individual S. rivulatus have a defined home range of about 200 m in length, from which they seldom venture. They repeatedly visit the same areas and return to the same sleeping grounds, thus providing evidence for their ability to navigate in the reef environment. Using a clustering algorithm to analyze segments of daily trajectories, we found evidence of specific repeating patterns in behavior within the home range of individual fish. Thus, S. rivulatus appears to have the ability to carry out its daily routines and revisit places of interest by employing sophisticated means of navigation while exploring its surroundings. In the future, using novel technologies for wireless recording from single cells of fish brains, S. rivulatus can emerge as an ideal system to study the neural basis of navigation in natural settings and lead to "electrophysiology in the wild."


Assuntos
Recifes de Corais , Peixes , Animais , Peixes/fisiologia , Mamíferos
9.
Oecologia ; 199(3): 589-597, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35786776

RESUMO

Many laboratory experiments on aquatic vertebrates that inhabit closed water or coastal areas have highlighted negative effects of fast growth on swimming performance. Nonetheless, field studies on pelagic fishes have provided evidence of survival advantages of faster-growing individuals. To reconcile this contradiction, we examined the relationship between growth rate and swimming performance as a continuous function for juveniles of chub mackerel (Scomber japonicus) using 3D tracking analysis. For experiments, 20, 24, 27, and 30 days post-hatch individuals within the size range of 14.5-25.3 mm were used. We found that the growth-swimming (burst speed) relationship in chub mackerel was substantially positive and it was supported by morphological traits such as muscle area, which were also positively related with growth rate. This finding is consistent with field observations showing selective survival of fast-growing individuals of this species, reconciling the current contradiction between laboratory experiments and field observations. A dome-shaped quadratic curve described the relationship between growth rate and burst speed better than a linear or cubic function, suggesting that growth may trade-off with swimming performance, as reported in many previous studies, when it is extremely fast. These results, obtained from the rarely tested offshore species, strongly suggests the importance of experimental verification using animals that inhabit various types of habitats in understanding the principles underlying the evolution of growth-locomotor relationship.


Assuntos
Peixes , Perciformes , Animais , Ecossistema , Peixes/fisiologia , Perciformes/fisiologia , Natação/fisiologia
10.
Sci Rep ; 12(1): 9848, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35701513

RESUMO

Animals that continually live in deep sea habitats face unique challenges and require adaptive specializations solutions in order to locate and identify food, predators, and conspecifics. The Ampullae of Lorenzini are specialized electroreceptors used by chondrichthyans for important biological functions. Ampullary organs of the ghost shark Chimaera monstrosa, a deep-sea species commonly captured as by-catch in the bottom trawl fishery, are here described for the first time using macroscopic, ultrastructural and histological approaches. The number of ampullary pores in C. monstrosa is about 700, distributed into the whole cephalic section of C. monstrosa, and organized in12 pore clusters and they are arranged into different configurations and form a distinct morphological pattern for this species, showing some anatomical peculiarities never described before in others cartilaginous fishes and may constitute an evolutionary adaptation of this ancient chondrichthyan species to the extreme environmental conditions of its deep sea niche.


Assuntos
Peixes , Tubarões , Adaptação Fisiológica , Animais , Evolução Biológica , Ecossistema , Peixes/fisiologia , Tubarões/anatomia & histologia
11.
J Exp Zool A Ecol Integr Physiol ; 337(7): 715-723, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35652427

RESUMO

Caffeic acid is a phenolic metabolite known for its beneficial pharmaceutical effects and is suggested as a functional additive for aquaculture. In this study, the effects of caffeic acid on the growth performance, growth genes, digestive enzyme activity, and serum immune parameters of beluga (Huso huso) were investigated. For this purpose, 120 beluga juveniles (367.75 ± 21.32 g) were divided into 12 tanks and fed with caffeic acid at rates of 0 (T0, control), 1 (T1), 5 (T2), and 10 (T3) g/kg for 56 days. The final weight and weight gain of beluga were significantly higher in fish fed 5 (T2) and 10 (T3) g caffeic acid/kg than in the control group and 1 (T1) g caffeic acid/kg. The specific growth rate was significantly higher in beluga fed 10 g caffeic acid/kg than 0 and 1 g/kg. Compared with the control group, the amylase, lipase, and pepsin activities were significantly higher in T2 and T3. The relative expression of growth hormone and insulin-like growth factor significantly increased in T3 compared with the control group. The expression of lipoprotein lipase and nuclear factor interleukin 3 of beluga fed 5 and 10 g caffeic acid/kg was higher than the control group. The lysozyme activity, total immunoglobulin, and total protein in the serum of beluga significantly increased in fish fed with caffeic acid at different rates compared with the control group. Based on the finding, the results suggested that the inclusion of caffeic acid (5-10 g/kg) in the diets of beluga is recommended to enhance the growth performance, some digestive enzyme activity, and serum immune parameters.


Assuntos
Suplementos Nutricionais , Peixes , Animais , Ácidos Cafeicos , Dieta , Peixes/fisiologia , Gelatina
12.
J R Soc Interface ; 19(191): 20210906, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35730177

RESUMO

The risk of predation presents a difficult challenge in environments that offer no physical shelter, such as the open waters of the world's seas. In the absence of hiding places, many marine fishes turn to two main anti-predator strategies: aggregation and camouflage, which, mostly, have been studied separately. Here, we consider both aspects together and examine the visual imprint of fish schools of different sizes and geometries, given that camouflage is attained by specular (mirror-like) skin texture. To do so, we developed ray-tracing simulations that model the passage of sunbeams as they go through an optically realistic aquatic environment and reflect off the skins of the fish. We find that due to frequent high-intensity specular reflections (light flashes), the marginal increase in detectability with increasing school size is significantly higher than previously estimated under the assumption of diffusive reflection. However, we also find that by increasing density and alignment the fish can mitigate the detectability of individuals, albeit at the expense of the detectability of the school as a whole. Our findings provide a new perspective on documented responses to threat by schooling pelagic fishes and underscore the importance of the optical signature of animals in structuring their behaviour.


Assuntos
Peixes , Comportamento Predatório , Animais , Peixes/fisiologia , Oceanos e Mares , Instituições Acadêmicas
13.
J Exp Biol ; 225(8)2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35502693

RESUMO

Amphibiousness in fishes spans the actinopterygian tree from the earliest to the most recently derived species. The land environment requires locomotor force production different from that in water, and a diversity of locomotor modes have evolved across the actinopterygian tree. To compare locomotor mode between species, we mapped biomechanical traits on an established amphibious fish phylogeny. Although the diversity of fish that can move over land is large, we noted several patterns, including the rarity of morphological and locomotor specialization, correlations between body shape and locomotor mode, and an overall tendency for amphibious fish to be small. We suggest two idealized empirical metrics to consider when gauging terrestrial 'success' in fishes and discuss patterns of terrestriality in fishes considering biomechanical scaling, physical consequences of shape, and tissue plasticity. Finally, we suggest four ways in which neural control could change in response to a novel environment, highlighting the importance and challenges of deciphering when these control mechanisms are used. We aim to provide an overview of the diversity of successful amphibious locomotion strategies and suggest several frameworks that can guide the study of amphibious fish and their locomotion.


Assuntos
Peixes , Locomoção , Animais , Fenômenos Biomecânicos , Peixes/fisiologia , Locomoção/fisiologia , Fenótipo , Filogenia
14.
Horm Behav ; 143: 105199, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35597053

RESUMO

Previous data suggested that activation of endocannabinoid receptor 1 (CB1) was necessary for the orexigenic effect of Ghrelin in rodents, but the information is limited in teleosts. To investigate the feeding regulation pathway of Ghrelin and CB1 in Siberian sturgeon (Acipenser baerii), this study first identified the Ghrelin (345 bp, complete coding sequence) and Ghrelin receptor (GHSR, 500 bp, partial coding sequence) sequences, and then detected their tissue distribution patterns, which showed that Ghrelin is mainly distribution in peripheral tissues, while GSHR is mainly in different brain divisions. Besides, the qPCR before and after feeding showed that the mRNA expressions of Ghrelin and GHSR were inhibited after feeding in telencephalon, diencephalon and mesencephalon. Subsequently, the food intake and appetite factor expressions were measured by i.c.v. co-injection of Ghrelin and GSHR antagonist. The results showed that Ghrelin promoted the food intake of Siberian sturgeon, which was reversed by its receptor antagonist. Besides, i.c.v. injection of Ghrelin decreased telencephalon CART expression while increased NPY expression in the three brain regions. In addition, to further explore the relationship of Ghrelin and CB1 signal regulating feeding, the co-injection of Ghrelin and CB1 antagonists was performed. The results showed that AM6545 (CB1 peripheral restricted antagonist) failed to affect the orexigenic effect of Ghrelin and the expression pattern of NPY mRNA in the telencephalon. While in the diencephalon, the increase of food intake and NPY mRNA expression induced by Ghrelin was completely reversed by Rimonabant (CB1 global antagonist). These results indicate Ghrelin-GSHR pathway promotes the food intake of Siberian sturgeon by inducing the expression of NPY in the diencephalon, and the stimulating effect will be reversed by cannabinoid receptor antagonism. This study provides a foundation for understanding the pathways Ghrelin and CB1 signals in appetite regulation of the teleost.


Assuntos
Grelina , Receptores de Grelina , Animais , Ingestão de Alimentos , Endocanabinoides/metabolismo , Endocanabinoides/farmacologia , Peixes/fisiologia , Grelina/metabolismo , Grelina/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Grelina/metabolismo
15.
Environ Toxicol Chem ; 41(8): 1967-1976, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35622057

RESUMO

The offshore oil industry in Atlantic Canada necessitates a greater understanding of the potential impacts of oil exposure and spill response measures on cold-water marine species. We used a standardized scoring index to characterize sublethal developmental impacts of physically and chemically dispersed crude oil in early life stages of Atlantic cod (Gadus morhua) and assessed intraspecific variation in the response among cod families. Cod (origin: Scotian Shelf, Canada) were laboratory-crossed to produce embryos from five specific families, which were subsequently exposed prehatch to gradient dilutions of a water-accommodated fraction (WAF) and a chemically enhanced WAF (CEWAF; prepared with Corexit 9500A) for 24 h. Postexposure, live embryos were transferred into filtered seawater and monitored to hatch; then, all live fish had sublethal endpoints assessed using the blue-sac disease (BSD) severity index. In both WAF and CEWAF groups, increasing exposure concentrations (measured as total petroleum hydrocarbons) resulted in an increased incidence of BSD symptoms (impaired swimming ability, increased degree of spinal curvature, yolk-sac edemas) in cod across all families. This positive concentration-dependent increase in BSD was similar between physically (WAF) versus chemically (CEWAF) dispersed oil exposures, indicating that dispersant addition does not exacerbate the effect of crude oil on BSD incidence in cod. Sensitivity varied between families, with some families having less BSD than others with increasing exposure concentrations. To our knowledge, our study is the first to demonstrate the occurrence in fishes of intraspecific variation among families in sublethal responses to oil and dispersant exposure. Our results suggest that sublethal effects of crude oil exposure will not be uniformly observed across cod populations and that sensitivity depends on genetic background. Environ Toxicol Chem 2022;41:1967-1976. © 2022 SETAC.


Assuntos
Gadus morhua , Poluição por Petróleo , Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Animais , Peixes/fisiologia , Lipídeos/química , Petróleo/análise , Petróleo/toxicidade , Poluição por Petróleo/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/análise , Água , Poluentes Químicos da Água/toxicidade
16.
Glob Chang Biol ; 28(17): 5104-5120, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35583053

RESUMO

Investigating the effects of climatic variability on biological diversity, productivity, and stability is key to understanding possible futures for ecosystems under accelerating climate change. A critical question for estuarine ecosystems is, how does climatic variability influence juvenile recruitment of different fish species and life histories that use estuaries as nurseries? Here we examined spatiotemporal abundance trends and environmental responses of 18 fish species that frequently spend the juvenile stage rearing in the San Francisco Estuary, CA, USA. First, we constructed multivariate autoregressive state-space models using age-0 fish abundance, freshwater flow (flow), and sea surface temperature data (SST) collected over four decades. Next, we calculated coefficients of variation (CV) to assess portfolio effects (1) within and among species, life histories (anadromous, marine opportunist, or estuarine dependent), and the whole community; and (2) within and among regions of the estuary. We found that species abundances varied over space and time (increasing, decreasing, or dynamically stable); and in 83% of cases, in response to environmental conditions (wet/dry, cool/warm periods). Anadromous species responded strongly to flow in the upper estuary, marine opportunist species responded to flow and/or SST in the lower estuary, and estuarine dependent species had diverse responses across the estuary. Overall, the whole community when considered across the entire estuary had the lowest CV, and life histories and species provided strong biological insurance to the portfolio (2.4- to 3.5-fold increases in stability, respectively). Spatial insurance also increased stability, although to a lesser extent (up to 1.6-fold increases). Our study advances the notion that fish recruitment stability in estuaries is controlled by biocomplexity-life history diversity and spatiotemporal variation in the environment. However, intensified drought and marine heatwaves may increase the risk of multiple consecutive recruitment failures by synchronizing species dynamics and trajectories via Moran effects, potentially diminishing estuarine nursery function.


Assuntos
Ecossistema , Água Doce , Animais , Mudança Climática , Estuários , Peixes/fisiologia
17.
Sci Total Environ ; 838(Pt 1): 155953, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-35588834

RESUMO

Predicting the impacts of species introductions long has attracted the attention of ecologists yet there still is limited insight into how impacts on native assemblages vary with the degree of shared evolutionary context. Here, we used data from 535 stream-fish surveys from 15 catchments in north-eastern Spain (99,700 km2) to explore whether the relative effects on native fishes differ between fish introductions from two different ecoregions (i.e., evolutionary contexts), namely, catchments within Iberian Peninsula (i.e., 'translocated species') and catchments beyond Iberian Peninsula (i.e., 'exotic fishes'). We used hierarchical Bayesian models to relate taxon richness, abundance, and the individual-size distributions (ISDs) of native fishes to the presence, abundance, and weighted trophic level (TL) of translocated and exotic fishes, conditional on geographic and habitat covariates. Environmental covariates dominated the percentage of explained variance (≥ 65%) for all responses. Translocated fishes accounted for more of the explained variance than did exotic fishes for ISDs and abundance, but not for native fish species richness. The presence of translocated fishes was associated with lower abundance and richness of native fishes, with individuals being smaller in the presence of translocated fishes of higher TL. The presence of exotic fishes was associated with a greater abundance and richness of native fishes, with individuals generally being larger in the presence of exotic fishes. Our study suggests that translocated fishes could be as problematic as exotic fishes when angling and water transfers among catchments to deal with climate change may increase the establishment of translocated fishes. We also discuss the difficulties of using fish body size as species-blind, transferable assemblage-level trait in fish monitoring.


Assuntos
Peixes , Rios , Animais , Teorema de Bayes , Biodiversidade , Evolução Biológica , Ecossistema , Peixes/fisiologia
18.
Fish Physiol Biochem ; 48(3): 693-705, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35501527

RESUMO

Insulin plays an important role in maintaining energy homeostasis and has the potential to be an indicator of energy homeostasis in the Yangtze sturgeon, Acipenser dabryanus. In this study, the Yangtze sturgeon insulin (Adinsulin) was cloned and characterized. To evaluate the possibility of insulin as an energy state assessment indicator, quantification real-time PCR (qRT-PCR) was used to evaluate expression changes in different tissues (the whole brain, esophagus, cardiac stomach, pyloric stomach, pyloric caeca, duodenum, valvula intestine, rectum, liver, pancreas, spleen, kidney, heart, muscle, gill and eye) from 6 fish (average weight 325.7 ± 22.3 g) and in three experiments including postprandial, fasting and re-feeding, and glucose tolerance treatment in which fish were divided into two groups including a group that administered a glucose solution (1 ul/g body weight) and another group that administered sterile water as control. In these three experiments, 6 fish were sampled, respectively, then been used to evaluate expression changes of insulin. All fish in feeding groups were fed in tanks (60.0 cm × 50.0 cm × 40.0 cm) with a commercial diet (crude protein ≥ 40%, crude fat ≥ 12%, coarse fiber ≤ 6%, crude ash ≤ 18%; TONGWEI CO., LTD, China) once a day at 16:00. The result showed that Adinsulin was highly expressed in the pancreas, which was the basis for the next experiment to use the pancreas as the test target. Adinsulin expression significantly increased 1 h after feeding and decreased rapidly after 3 h of feeding, but it was still significantly higher than that of the group without feeding (P < 0.01). Compared to the feeding group, the expression of Adinsulin was significantly reduced in the fasting group of 3 days (P < 0.01), 6 days (P < 0.01), 10 days (P < 0.05), 11 days (P < 0.05) and 13 days (P < 0.01) and was no significant difference in re-feeding for 1st day, 2nd day and 4th day, but there was difference between re-feeding group and fasting group. After glucose tolerance treatment, serum glucose levels increased significantly (P < 0.05), accompanied by a significant increase (P < 0.001) in insulin expression. This study result shows that insulin has the capacity to measure the energy homeostasis of Yangtze sturgeon. Further development of detection methods for sturgeon plasma or serum insulin will avoid slaughtering animals and is more practical in energy homeostasis assessment.


Assuntos
Peixes , Insulinas , Animais , Biomarcadores/metabolismo , Peixes/fisiologia , Glucose/metabolismo , Homeostase , Insulinas/metabolismo
19.
Gen Comp Endocrinol ; 323-324: 114044, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35472317

RESUMO

Individuals within a population present behavioral responses that vary according to intrinsic and extrinsic factors such as ontogenetic phase, nutritional status, reproductive stage, and previous experiences. These differences can be explained by endogenous changes, such as hormone release, that can modulate reproductive behaviors, stress response, and cognitive processes. In order to investigate the relationship between behavior and hormonal levels in the fighting fish Betta splendens, the present study characterized nest building, aggressive behavior, learning of a task, and levels of cortisol and 11-ketotestosterone (11-KT) in 86 male Fighting fish. At the beginning of the experiment (days 1-4), fish were characterized as nest builders, intermediate builders, or non-builders. They were then sequentially tested for aggression (days 7-8), learning performance (days 11-21), and circulating hormone levels (day 23). Nest builders showed the lowest hormonal levels at the end of the experiment and low aggressiveness; Intermediate builders presented low cortisol, but high KT levels and best learned the task; Non-builders were the most aggressive animals with higher cortisol levels (at day 23). Our data suggest that in B. splendens, aggressive behavior and learning performance are related to the relative investment in reproduction and variation in circulating levels of corticosteroids and androgens.


Assuntos
Peixes , Hidrocortisona , Agressão , Androgênios/fisiologia , Animais , Peixes/fisiologia , Aprendizagem , Masculino
20.
Bioinspir Biomim ; 17(4)2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35487201

RESUMO

Many aquatic animals swim by undulatory body movements and understanding the diversity of these movements could unlock the potential for designing better underwater robots. Here, we analyzed the steady swimming kinematics of a diverse group of fish species to investigate whether their undulatory movements can be represented using a series of interconnected multi-segment models, and if so, to identify the key factors driving the segment configuration of the models. Our results show that the steady swimming kinematics of fishes can be described successfully using parsimonious models, 83% of which had fewer than five segments. In these models, the anterior segments were significantly longer than the posterior segments, and there was a direct link between segment configuration and swimming kinematics, body shape, and Reynolds number. The models representing eel-like fishes with elongated bodies and fishes swimming at high Reynolds numbers had more segments and less segment length variability along the body than the models representing other fishes. These fishes recruited their anterior bodies to a greater extent, initiating the undulatory wave more anteriorly. Two shape parameters, related to axial and overall body thickness, predicted segment configuration with moderate to high success rate. We found that head morphology was a good predictor of its segment length. While there was a large variation in head segments, the length of tail segments was similar across all models. Given that fishes exhibited variable caudal fin shapes, the consistency of tail segments could be a result of an evolutionary constraint tuned for high propulsive efficiency. The bio-inspired multi-segment models presented in this study highlight the key bending points along the body and can be used to decide on the placement of actuators in fish-inspired robots, to model hydrodynamic forces in theoretical and computational studies, or for predicting muscle activation patterns during swimming.


Assuntos
Peixes , Natação , Animais , Evolução Biológica , Fenômenos Biomecânicos/fisiologia , Peixes/fisiologia , Hidrodinâmica , Natação/fisiologia
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