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1.
PLoS One ; 19(5): e0291886, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38768157

RESUMO

Duoculture has been reported to increase growth rates of some fishes when reared in combination, due to "shading" effects between the species. Two experiments, one involving outdoor cage-rearing in a reservoir, and the other, indoor tank-rearing, were conducted within each of three temperatures ranges (means of ~18.0°C, ~22.0°C and ~26.5°C), to determine whether duoculture of bluegill (BG) Lepomis macrochirus and yellow perch (YP) Perca flavescens would lead to improved growth relative to when the two species were reared separately. Juvenile bluegill and yellow perch were reared in triplicated groups each involving monoculture sets of 100% BG and 100% YP, and a duoculture set of 50% BG + 50% YP. Experiments in cages (Exp. 1) ran for 150 days while those in tanks ran for 126 days (Exp. 2). In Experiment 1, bluegill exhibited significantly greater (P<0.05) mean weight (P<0.05) in duoculture than in monoculture, under the high summer-like range of temperature (~26.5°C) over most of the experiment, whereas yellow perch showed no significant difference in mean weight in duoculture versus monoculture. By the end of a 150-d experiment, bluegill in duoculture outweighed those in monoculture by 62.5%. In Experiment 2, yellow perch in duoculture grew significantly larger than in monoculture (P<0.05) under the warm thermal regime (mean of ~22°C), while no significant differences were detected in mean weight of bluegill in monoculture versus duoculture. Yellow perch in duoculture outweighed those in monoculture by 33.1% at the end of the experiment. Yellow perch performed better in duoculture than in monoculture under the low thermal regime (mean of ~18°C) in both experiments. A significantly greater reduction of CVwt was observed for both bluegill and yellow perch in duoculture than in monoculture in Experiment 1, while no differences in CVwt reduction were detected for bluegill in Experiment 2. Feed conversion ratios (FCR) of bluegill and yellow perch reared in duoculture were significantly lower than for both fishes reared in monoculture in Experiment 1, while there were no significant differences in FCR among the three groups throughout most of Experiment 2. Findings indicate that duoculture of yellow perch and bluegill holds good potential to improve growth and FCR, and to reduce size variation by diminishing social interaction costs.


Assuntos
Percas , Temperatura , Animais , Percas/crescimento & desenvolvimento , Percas/fisiologia , Peixes/crescimento & desenvolvimento , Peixes/fisiologia , Perciformes/crescimento & desenvolvimento , Perciformes/fisiologia , Comportamento Social
2.
Proc Biol Sci ; 291(2023): 20232207, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38772423

RESUMO

Population and species persistence in a rapidly warming world will be determined by an organism's ability to acclimate to warmer conditions, especially across generations. There is potential for transgenerational acclimation but the importance of ontogenetic timing in the transmission of environmentally induced parental effects remains mostly unknown. We aimed to disentangle the effects of two critical ontogenetic stages (juvenile development and reproduction) to the new-generation acclimation potential, by exposing the spiny chromis damselfish Acanthochromis polyacanthus to simulated ocean warming across two generations. By using hepatic transcriptomics, we discovered that the post-hatching developmental environment of the offspring themselves had little effect on their acclimation potential at 2.5 months of life. Instead, the developmental experience of parents increased regulatory RNA production and protein synthesis, which could improve the offspring's response to warming. Conversely, parental reproduction and offspring embryogenesis in warmer water elicited stress response mechanisms in the offspring, with suppression of translation and mitochondrial respiration. Mismatches between parental developmental and reproductive temperatures deeply affected offspring gene expression profiles, and detrimental effects were evident when warming occurred both during parents' development and reproduction. This study reveals that the previous generation's developmental temperature contributes substantially to thermal acclimation potential during early life; however, exposure at reproduction as well as prolonged heat stress will likely have adverse effects on the species' persistence.


Assuntos
Aclimatação , Recifes de Corais , Animais , Reprodução , Aquecimento Global , Perciformes/fisiologia , Transcriptoma , Oceanos e Mares , Peixes/fisiologia , Temperatura
3.
PLoS One ; 19(5): e0301456, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38718023

RESUMO

The round goby (Neogobius melanostomus) is an invasive benthic fish first introduced to the Laurentian Great Lakes in 1990 that has negatively impacted native fishes through increased competition for food and habitat, aggressive interactions, and egg predation. While complete eradication of the round goby is currently not possible, intensive trapping in designated areas during spawning seasons could potentially protect critical native fish spawning habitats. Baited minnow traps were spaced 10 meters apart in shallow water along a 100-meter stretch of shoreline within the Duluth-Superior Harbor during the round goby breeding period (June to October) with captured round gobies removed from interior traps (N = 10) every 48 hours. These traps were bracketed by two pairs of reference traps deployed weekly for 48 hours, from which round gobies were also tagged and released. The number of round gobies captured in the interior traps declined by 67% compared to reference traps over the course of the study, with extended periods of no captures. The tagged round gobies showed high site affinity, with 82.8% of tagged fish recaptured at the previous release site. The results indicate that even at open water sites, which allow natural migration of round gobies into the area, extensive trapping could reduce local population numbers.


Assuntos
Espécies Introduzidas , Animais , Ecossistema , Densidade Demográfica , Perciformes/fisiologia , Peixes/fisiologia , Lagos
4.
Glob Chang Biol ; 30(5): e17273, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38727723

RESUMO

Rapid warming at high latitudes triggers poleward shifts of species' distributions that impact marine biodiversity. In the open sea, the documented redistributions of fish lead to a borealization of Arctic fauna. A climate-driven borealization and increased species diversity at high latitudes are also expected in coastal fish communities, but they have not been previously documented on a large, biogeographic scale. Here, we investigate the impact of temperature change over the last 25 years on fish communities along the coast of Norway. The study area, spanning different ecoclimatic zones between 62° and 71° N, harbors over 200 species of boreal and Arctic fish. Several of these fish species are harvested by coastal and indigenous communities, influencing settlement geography and livelihood. The long-term data on coastal water temperatures and fish species were obtained from monitoring stations and scientific surveys. Water temperature measured at three fixed sampling stations distributed along the coast show increased temperatures during the study period. The fish species distribution and abundance data were obtained from the annually standardized scientific bottom trawl survey program. Fish species richness, which was highest in the south, increased with warming first in the south and then, gradually, further north, eventually affecting biodiversity in the whole study area. Fish community composition showed a distinct latitudinal pattern early in the study, with Arctic fish species confined to the north and boreal species dominating the south. The poleward shifts eventually eroded this zoogeographic pattern, resulting in more boreal fish species in the north and an increased homogenization of species composition along the Norwegian coast. The climate-driven reorganization of fish communities affects coastal ecosystems that are exposed to fisheries, aquaculture, and other rapidly expanding human activities, stressing the urgent need for a climate adaptation of integrated coastal management.


Assuntos
Biodiversidade , Mudança Climática , Peixes , Temperatura , Animais , Peixes/fisiologia , Noruega , Regiões Árticas
5.
PLoS One ; 19(5): e0302738, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38709717

RESUMO

Thousands of offshore oil and gas platforms have been installed throughout the world's oceans and more structures are being installed as part of the transition to renewable energy. These structures increase the availability of ecological niches by providing hard substrate in midwater and complex 3D habitat on the seafloor. This can lead to 'hotspots' of biodiversity, or increased densities of flora and fauna, which potentially spill over into the local area. However, the distances over which these higher densities extend (the 'range of influence') can be highly variable. Fish aggregate at such structures, but the range of influence and any implications for wider fish populations, are unclear. We investigated the relationship between fish and platform areal densities using high resolution fisheries acoustic data. Data were collected in the waters surrounding the vessel exclusions zones around 16 oil and gas platforms in the North Sea, and throughout the wider area. We estimated densities of schooling fish using echo-integration, and densities of non-schooling fish using echo-counting. At 10 platforms, non-schooling fish densities were elevated near the platform relative to background levels in the equivalent wider area. The range of influence, defined here as the range to which fish densities were elevated above background, varied from 0.8 to 23 km. In areas of high platform density, fish schools were encountered more often, and non-schooling fish densities were higher, when controlling for other sources of environmental variation. This is the first time such long-range effects have been identified; previously, ranges of influence have been reported in the order of just 10s-100s of metres. These findings suggest that the environmental impact of these structures may extend further than previously thought, which may be relevant in the context of upcoming management decisions around the decommissioning of these structures.


Assuntos
Peixes , Campos de Petróleo e Gás , Animais , Peixes/fisiologia , Densidade Demográfica , Ecossistema , Indústria de Petróleo e Gás , Mar do Norte
6.
PLoS One ; 19(5): e0301689, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38728315

RESUMO

Acoustic methods are often used for fisheries resource surveys to investigate fish stocks in a wide area. Commercial fisheries echo sounders, which are installed on most small fishing vessels, are used to record a large amount of data during fishing trips. Therefore, it can be used to collect the basic information necessary for stock assessment for a wide area and frequently. To carry out the quantification for the fisheries echo sounder, we devised a simple method using the backscattering strength of the seabed to perform calibration periodically and easily. In this study, seabed secondary reflections were used instead of primary reflection because the fisheries echo sounders were not equipped with a time-varied gain (TVG) function, and the primary backscattering strength of the seabed was saturated. It was also necessary to use standard values of seabed backscattering strength averaged over a certain area for calibration to eliminate some of the effects of differences in seabed sediment and vessel motions. By using standard values of the seabed secondary reflections, the fisheries echo sounder was calibrated accurately. Our study can provide a reliable framework to calibrate commercial fisheries echo sounders, to improve the estimation and management of fishery resources.


Assuntos
Pesqueiros , Calibragem , Animais , Acústica/instrumentação , Peixes/fisiologia , Conservação dos Recursos Naturais/métodos
7.
Sci Adv ; 10(19): eadi6580, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38728390

RESUMO

The impact of dams on global migratory fish stocks is a major challenge and remains seriously underestimated. China has initiated a dozen fish rescue programs for the dams on the Yangtze River, focusing on five flagship species-Chinese sturgeon, Chinese paddlefish, Yangtze sturgeon, Chinese sucker, and Coreius guichenoti. Despite 40 years of effort, these five fishes are on the verge of extinction. Here, we propose an analytical tool that includes a framework of fish migration taxonomy and six life cycle models, the concepts of invalid stock and the dam impact coefficient, and a simplified population model. We then clarify the migration patterns and life cycles of these fishes and show that the Yangtze dams have severely disrupted the life cycle integrity of these species, causing seven types of invalid stocks and their exponential population declines. Last, we discuss six scientific misjudgments underpinning the fish rescue programs and recommend reforms to China's fish rescue strategy.


Assuntos
Migração Animal , Conservação dos Recursos Naturais , Peixes , Dinâmica Populacional , Animais , Peixes/fisiologia , Migração Animal/fisiologia , China , Rios
8.
Glob Chang Biol ; 30(5): e17318, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38771091

RESUMO

Amphibians and fishes play a central role in shaping the structure and function of freshwater environments. These organisms have a limited capacity to disperse across different habitats and the thermal buffer offered by freshwater systems is small. Understanding determinants and patterns of their physiological sensitivity across life history is, therefore, imperative to predicting the impacts of climate change in freshwater systems. Based on a systematic literature review including 345 experiments with 998 estimates on 96 amphibian (Anura/Caudata) and 93 freshwater fish species (Teleostei), we conducted a quantitative synthesis to explore phylogenetic, ontogenetic, and biogeographic (thermal adaptation) patterns in upper thermal tolerance (CTmax) and thermal acclimation capacity (acclimation response ratio, ARR) as well as the influence of the methodology used to assess these thermal traits using a conditional inference tree analysis. We found globally consistent patterns in CTmax and ARR, with phylogeny (taxa/order), experimental methodology, climatic origin, and life stage as significant determinants of thermal traits. The analysis demonstrated that CTmax does not primarily depend on the climatic origin but on experimental acclimation temperature and duration, and life stage. Higher acclimation temperatures and longer acclimation times led to higher CTmax values, whereby Anuran larvae revealed a higher CTmax than older life stages. The ARR of freshwater fishes was more than twice that of amphibians. Differences in ARR between life stages were not significant. In addition to phylogenetic differences, we found that ARR also depended on acclimation duration, ramping rate, and adaptation to local temperature variability. However, the amount of data on early life stages is too small, methodologically inconsistent, and phylogenetically unbalanced to identify potential life cycle bottlenecks in thermal traits. We, therefore, propose methods to improve the robustness and comparability of CTmax/ARR data across species and life stages, which is crucial for the conservation of freshwater biodiversity under climate change.


Assuntos
Aclimatação , Anfíbios , Peixes , Água Doce , Aquecimento Global , Animais , Aclimatação/fisiologia , Peixes/fisiologia , Anfíbios/fisiologia , Anfíbios/crescimento & desenvolvimento , Filogenia , Mudança Climática , Temperatura
9.
PLoS One ; 19(5): e0303538, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38781230

RESUMO

In real-world situations, marine fish farms accommodate multiple fish species and cohorts within the farm, leading to diverse farm layouts influenced by cage dimensions, configurations, and intricate arrangements. These cage management practices are essential to meet production demands, however, farm-level complexities can impact model predictions of waste deposition and benthic impact near fish cages. This is of particular importance when the cages are used for integrated multi-trophic aquaculture (IMTA) with benthic feeders, where this waste not only affects environmental conditions but also provides a potential food source. The Cage Aquaculture Particulate Output and Transport (CAPOT) model incorporated multiple species, cohorts, and cage arrangements to estimate waste distribution from a commercial fish farm in the Mediterranean between October 2018 and July 2019. This spreadsheet model estimated dispersion for individual fish cages using a grid resolution of 5 m x 5 m. The study categorized discrete production periods for each fish cage every month, aligning with intermittent changes in biomass and food inputs due to different cage management practices throughout production. This approach facilitated the use of detailed input data and enhanced model representativeness by considering variations in cage biomass, food types, settling velocities, and configurations. Model outputs, represented in contour plots, indicated higher deposition directly below fish cages that varied monthly throughout fish production cycles. Deposition footprints reflected changes in cage biomass, food inputs, and farm-level practices reflecting this real-world scenario where aquaculture does not follow a production continuum. Moreover, cohort dynamics and cage movements associated with the cage management practices of the fish farm influenced the quantity and fate of wastes distributed around fish cages, revealing variability in deposition footprints. Clearly, these findings have important implications for the design of benthic IMTA systems, with species such as sea cucumber and polychaetes. Variability in waste deposition creates challenges in identifying where the benthic organisms should be placed to allow optimal uptake of waste to meet their food requirements and increase survivability. Evidently, models have an important role to play and this study emphasizes the need for representative input data to describe actual food inputs, cage biomass changes, and management practices for more representative farm-scale modelling and essentially to improve particulate waste management. To effectively mitigate benthic impacts through IMTA, models must quantify and resolve particulate waste distribution and impact around fish farms to maintain a balanced system with net removal of wastes. Resolving farm-level complexities provides vital information about the variability of food availability and quality for extractive organisms that helps improve recycling of organic wastes in integrated systems, demanding a more representative modelling approach.


Assuntos
Aquicultura , Peixes , Aquicultura/métodos , Animais , Peixes/fisiologia , Modelos Teóricos , Biomassa , Pesqueiros
10.
Bioinspir Biomim ; 19(4)2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38722377

RESUMO

State-of-the-art morphing materials are either very compliant to achieve large shape changes (flexible metamaterials, compliant mechanisms, hydrogels), or very stiff but with infinitesimal changes in shape that require large actuation forces (metallic or composite panels with piezoelectric actuation). Morphing efficiency and structural stiffness are therefore mutually exclusive properties in current engineering morphing materials, which limits the range of their applicability. Interestingly, natural fish fins do not contain muscles, yet they can morph to large amplitudes with minimal muscular actuation forces from the base while producing large hydrodynamic forces without collapsing. This sophisticated mechanical response has already inspired several synthetic fin rays with various applications. However, most 'synthetic' fin rays have only considered uniform properties and structures along the rays while in natural fin rays, gradients of properties are prominent. In this study, we designed, modeled, fabricated and tested synthetic fin rays with bioinspired gradients of properties. The rays were composed of two hemitrichs made of a stiff polymer, joined by a much softer core region made of elastomeric ligaments. Using combinations of experiments and nonlinear mechanical models, we found that gradients in both the core region and hemitrichs can increase the morphing and stiffening response of individual rays. Introducing a positive gradient of ligament density in the core region (the density of ligament increases towards the tip of the ray) decreased the actuation force required for morphing and increased overall flexural stiffness. Introducing a gradient of property in the hemitrichs, by tapering them, produced morphing deformations that were distributed over long distances along the length of the ray. These new insights on the interplay between material architecture and properties in nonlinear regimes of deformation can improve the designs of morphing structures that combine high morphing efficiency and high stiffness from external forces, with potential applications in aerospace or robotics.


Assuntos
Nadadeiras de Animais , Materiais Biomiméticos , Animais , Nadadeiras de Animais/fisiologia , Nadadeiras de Animais/anatomia & histologia , Fenômenos Biomecânicos , Biomimética/métodos , Peixes/fisiologia , Peixes/anatomia & histologia
11.
Sci Data ; 11(1): 521, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778024

RESUMO

Fish spawning locations are a crucial input into fisheries management and conservation plans, and many stocks are especially sensitive to the environmental conditions within these localized zones. Globally collated data on spawning locations across many species has been unavailable, hindering global stock assessments and analyses of sustainable development and global environmental change. To address this, we created a geocoded fish spawning dataset using qualitative spawning information from FishBase and Science and Conservation of Fish Aggregations (SCRFA). We cleaned and geocoded the spawning locations of 1,045 marine fish species into 2,931 regions. Each spawning region is defined by one or more polygons, and most spawning regions are associated with spawning months. The resulting dataset covers oceans globally. This dataset will be useful to scientists studying marine fish population dynamics and their interactions with the physical environment on regional to large scales.


Assuntos
Ecossistema , Peixes , Reprodução , Animais , Peixes/fisiologia , Pesqueiros , Dinâmica Populacional , Conservação dos Recursos Naturais , Oceanos e Mares
12.
Nat Commun ; 15(1): 3979, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38729972

RESUMO

A primary response of many marine ectotherms to warming is a reduction in body size, to lower the metabolic costs associated with higher temperatures. The impact of such changes on ecosystem dynamics and stability will depend on the resulting changes to community size-structure, but few studies have investigated how temperature affects the relative size of predators and their prey in natural systems. We utilise >3700 prey size measurements from ten Southern Ocean lanternfish species sampled across >10° of latitude to investigate how temperature influences predator-prey size relationships and size-selective feeding. As temperature increased, we show that predators became closer in size to their prey, which was primarily associated with a decline in predator size and an increase in the relative abundance of intermediate-sized prey. The potential implications of these changes include reduced top-down control of prey populations and a reduction in the diversity of predator-prey interactions. Both of these factors could reduce the stability of community dynamics and ecosystem resistance to perturbations under ocean warming.


Assuntos
Tamanho Corporal , Peixes , Oceanos e Mares , Comportamento Predatório , Temperatura , Animais , Comportamento Predatório/fisiologia , Tamanho Corporal/fisiologia , Peixes/fisiologia , Cadeia Alimentar , Ecossistema , Dinâmica Populacional
13.
Reprod Domest Anim ; 59(5): e14575, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38715442

RESUMO

Cryopreservation is a valuable technique used to assist in the genetic improvement of cultured stocks and provide a continuous supply of good-quality semen for artificial insemination. Conserving semen by cryopreservation serves several purposes (e.g. artificial reproductive technologies and species conservation) and is also used in the clinical treatment of human infertility. However, the lifespan of cryopreserved semen is influenced by a range of factors, including storage temperature, cooling rate, chemical composition of the extender, the concentration of cryoprotectant, reactive oxygen species, seminal plasma composition and hygienic control. The choice of cryoprotectant is a vital factor underlying the success of animal semen cryopreservation. In this regard, extensive research has been carried out on various cryoprotectants, such as egg yolk, dimethyl sulfoxide, methanol, ethylene glycol and dimethylacetamide. Recent studies have also described the use of a range of new cryoprotectants for cryopreservation, including compounds of plant origin (soy), amino acids, antifreeze proteins, carbohydrates and cyclodextrins. Moreover, semen cryopreservation and storage require the use of liquid nitrogen or ultralow refrigeration methods for both long- and short-term storage. This review summarizes the general methods used for freezing semen and discusses the use of traditional and newly emerging cryoprotectants (permeable and non-permeable) for the cryopreservation of semen in selected fish and mammalian species.


Assuntos
Criopreservação , Crioprotetores , Peixes , Mamíferos , Preservação do Sêmen , Crioprotetores/farmacologia , Criopreservação/veterinária , Criopreservação/métodos , Animais , Preservação do Sêmen/veterinária , Preservação do Sêmen/métodos , Masculino , Peixes/fisiologia , Sêmen
14.
J Environ Manage ; 359: 121053, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38723501

RESUMO

Biodiversity preservation is a primary challenge of the 21st century, focusing on restoring unobstructed river flows and mitigating the effects of barriers, supported by European biodiversity strategies up to 2030. Maintaining ecological continuity, such as unblocking fishways clogged by floating debris disrupting natural fish migration paths, remains a challenge despite conventional protective methods. This study, taking a vertical slot fish pass in Wroclaw on the Odra River as a case study and based on research on bridge piers, suggests modifying pier shapes from rectangular to rounded in order to reduce debris accumulation. Field studies, utilizing an OTT MF Pro flow meter, were conducted to validate the numerical model. The measured flow rate in the field was 3.15 [m³·s-1], while the numerical modeling yielded a flow of 3.19 [m³·s-1]. Focusing on optimizing the shape of cross-wall piers to enhance fish migration conditions, the study examined six different pier configurations, analyzing flow speed in the main slot, crucial for migration. Using 2D hydraulic modeling with Iber, it assessed the migratory potential of different pier designs by analyzing hydraulic conditions and comparing them with the swimming capabilities of fish species native to the Odra River. Results indicate that rounding the pier edges positively affects flow speeds in the main slot, enhancing fish migration possibilities, contributing to fish pass functionality improvement and supporting broader biodiversity and ecosystem health goals.


Assuntos
Migração Animal , Biodiversidade , Peixes , Rios , Animais , Peixes/fisiologia , Conservação dos Recursos Naturais
15.
Commun Biol ; 7(1): 578, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755224

RESUMO

Path integration is a powerful navigational mechanism whereby individuals continuously update their distance and angular vector of movement to calculate their position in relation to their departure location, allowing them to return along the most direct route even across unfamiliar terrain. While path integration has been investigated in several terrestrial animals, it has never been demonstrated in aquatic vertebrates, where movement occurs through volumetric space and sensory cues available for navigation are likely to differ substantially from those in terrestrial environments. By performing displacement experiments with Lamprologus ocellatus, we show evidence consistent with fish using path integration to navigate alongside other mechanisms (allothetic place cues and route recapitulation). These results indicate that the use of path integration is likely to be deeply rooted within the vertebrate phylogeny irrespective of the environment, and suggests that fish may possess a spatial encoding system that parallels that of mammals.


Assuntos
Sinais (Psicologia) , Animais , Navegação Espacial/fisiologia , Peixes/fisiologia
16.
Sci Rep ; 14(1): 11203, 2024 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755235

RESUMO

Seagrass habitats play a major role in fisheries productivity through nursery functions and feeding grounds for diverse fish species. However, little is known about the seasonal distribution of fish larvae at large spatial scales in coastal East Africa. We investigated drivers of the seasonal fish larvae abundance and composition in seagrass habitats in Kenya and Tanzania. We found a high diversity of fish larvae (54 families) inhabiting seagrass habitats that differed between sites and seasons. Fish larvae abundance were highest in Kenya, particularly during the northeast monsoon season. Overall, total larval abundances per site were low, reaching less than 190 individuals/100 m3 in Kenya and less than 40 individuals/100 m3 in Tanzania, likely related to the low productivity and strong hydrodynamic processes in this region. Our data suggests that most of the fish spawn year-round in these tropical waters as we did not find strong seasonal patterns. All sites had a high relative abundance of larvae from demersal spawning fishes, indicating that many fish species move to coastal sites for spawning. Primary productivity and dissolved oxygen, driven by hydrodynamics conditions are positively related to fish larvae productivity both in Kenya and Tanzania. These findings indicate that the occurrence of both resident and transient fish larvae in seagrass meadows is driven by strong hydrodynamic and tidal processes that transport fish larvae across adjacent habitats.


Assuntos
Ecossistema , Peixes , Larva , Estações do Ano , Animais , Peixes/fisiologia , Peixes/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Quênia , Tanzânia , África Oriental , Biodiversidade
17.
Sci Rep ; 14(1): 11158, 2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750135

RESUMO

Examples of symbiotic relationships often include cleaning mutualisms, typically involving interactions between cleaner fish and other fish, called the clients. While these cleaners can cooperate by removing ectoparasites from their clients, they can also deceive by feeding on client mucus, a behavior usually referred to as "cheating behavior" that often leads to a discernible jolt from the client fish. Despite extensive studies of these interactions, most research has focused on the visual aspects of the communication. In this study, we aimed to explore the role of acoustic communication in the mutualistic relationship between cleaner fishes and nine holocentrid client species across four regions of the Indo-Pacific Ocean: French Polynesia, Guam, Seychelles, and the Philippines. Video cameras coupled with hydrophones were positioned at various locations on reefs housing Holocentridae fish to observe their acoustic behaviors during interactions. Our results indicate that all nine species of holocentrids can use acoustic signals to communicate to cleaner fish their refusal of the symbiotic interaction or their desire to terminate the cooperation. These sounds were predominantly observed during agonistic behavior and seem to support visual cues from the client. This study provides a novel example of acoustic communication during a symbiotic relationship in teleosts. Interestingly, these vocalizations often lacked a distinct pattern or structure. This contrasts with numerous other interspecific communication systems where clear and distinguishable signals are essential. This absence of a clear acoustic pattern may be because they are used in interspecific interactions to support visual behavior with no selective pressure for developing specific calls required in conspecific recognition. The different sound types produced could also be correlated with the severity of the client response. There is a need for further research into the effects of acoustic behaviors on the quality and dynamics of these mutualistic interactions.


Assuntos
Simbiose , Animais , Simbiose/fisiologia , Peixes/fisiologia , Som , Acústica , Vocalização Animal/fisiologia , Comunicação Animal , Recifes de Corais , Oceano Pacífico , Polinésia , Perciformes/fisiologia
18.
Sci Rep ; 14(1): 10177, 2024 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702432

RESUMO

The challenges of commercial species with the threats of climate change make it necessary to predict the changes in the distributional shifts and habitat preferences of the species under possible future scenarios. We aim to demonstrate how future climatic changes will affect the habitat suitability of three species of commercial fish using the predictive technique MaxEnt. The dataset used to extract geographical records included OBIS (54%), GBIF (1%), and literature (45%). The output of the model indicated accurate projections of MaxEnt (AUC above 0.9). Temperature was the main descriptor responsible for the main effects on the distribution of commercial fish. With increasing RCP from 2.5 to 8.5, the species would prefer saltier, higher temperatures and deeper waters in the future. We observed different percentages of suitable habitats between species during RCPs showing distinct sensitivity of each fish in facing climate changes. Negative effects from climate change on the distribution patterns of commercial fish were predicted to lead to varying degrees of reduction and changes of suitable habitats and movement of species towards higher latitudes. The finding emphasizes to implement adaptive management measures to preserve the stocks of these commercial fish considering that the intensification of the effects of climate change on subtropical areas and overexploited species is predicted.


Assuntos
Mudança Climática , Ecossistema , Peixes , Animais , Peixes/fisiologia , Temperatura , Pesqueiros
19.
J Theor Biol ; 588: 111821, 2024 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-38649020

RESUMO

Fish schooling has the improvement in hydrodynamic propulsive efficiency through the interaction of flow field induced by fish bodies and tail beat. Such energy-saving behaviors due to flow interactions also occur with changes in the flow field caused by structures. We examined the differences between a live fish swimming around a streamlined hydrofoil model prepared to represent fish body and swimming alone in a flow tank. We observed that the fish can remain in the same place without tail beating. It called "drafting" behavior. The analysis of fish drafting showed that fish obtained thrust using a local pressure drop caused by the high velocity flow even in the vicinity of the hydrofoil model at an angle of attack α of 10° to 20°without flow separation, and fish balanced forces by using an α of fish body. This tendency was confirmed in the model experiment using a two-axis load cell, and the forces acting on the fish body was the smallest value when the fish model was placed in the same conditions as a live fish experiment. We also confirmed by simulation and found that the α of fish body generated lift force and counteract the suction force. Above results indicate that a fish can balance the anterior-posterior and lateral direction forces by using a local pressure drop around a hydrofoil model as suction force, and using angle of attack on its body, thereby realizing drafting.


Assuntos
Modelos Biológicos , Pressão , Natação , Animais , Natação/fisiologia , Fenômenos Biomecânicos , Peixes/fisiologia , Hidrodinâmica , Comportamento Animal/fisiologia
20.
Biomolecules ; 14(4)2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38672450

RESUMO

Motilin is a gastrointestinal hormone that is mainly produced in the duodenum of mammals, and it is responsible for regulating appetite. However, the role and expression of motilin are poorly understood during starvation and the weaning stage, which is of great importance in the seeding cultivation of fish. In this study, the sequences of Yangtze sturgeon (Acipenser dabryanus Motilin (AdMotilin)) motilin receptor (AdMotilinR) were cloned and characterized. The results of tissue expression showed that by contrast with mammals, AdMotilin mRNA was richly expressed in the brain, whereas AdMotilinR was highly expressed in the stomach, duodenum, and brain. Weaning from a natural diet of T. Limnodrilus to commercial feed significantly promoted the expression of AdMotilin in the brain during the period from day 1 to day 10, and after re-feeding with T. Limnodrilus the change in expression of AdMotilin was partially reversed. Similarly, it was revealed that fasting increased the expression of AdMotilin in the brain (3 h, 6 h) and duodenum (3 h), and the expression of AdMotilinR in the brain (1 h) in a time-dependent manner. Furthermore, it was observed that peripheral injection of motilin-NH2 increased food intake and the filling index of the digestive tract in the Yangtze sturgeon, which was accompanied by the changes of AdMotilinR and appetite factors expression in the brain (POMC, CART, AGRP, NPY and CCK) and stomach (CCK). These results indicate that motilin acts as an indicator of nutritional status, and also serves as a novel orexigenic factor that stimulates food intake in Acipenser dabryanus. This study lays a strong foundation for the application of motilin as a biomarker in the estimation of hunger in juvenile Acipenser dabryanu during the weaning phase, and enhances the understanding of the role of motilin as a novel regulator of feeding in fish.


Assuntos
Comportamento Alimentar , Peixes , Motilina , Animais , Encéfalo/metabolismo , Proteínas de Peixes/metabolismo , Peixes/metabolismo , Peixes/genética , Peixes/fisiologia , Motilina/genética , Motilina/metabolismo , Motilina/farmacologia , Receptores dos Hormônios Gastrointestinais/metabolismo , Receptores dos Hormônios Gastrointestinais/genética , Receptores de Neuropeptídeos/metabolismo , Receptores de Neuropeptídeos/genética
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