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1.
J Exp Biol ; 225(8)2022 Apr 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
2.
Bioinspir Biomim ; 17(4)2022 May 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
3.
J Exp Biol ; 225(8)2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35315489

RESUMO

Winter dormancy is a seasonal survival strategy common among temperate ectotherms, characterized by inactivity, fasting and low metabolic rates. Previous reports of metabolic rate depression (MRD) in winter-dormant ectotherms, including many fishes, may have resulted from confounding influences of temperature-dependent variation in activity on metabolic rate measurements. We hypothesize that, as demonstrated recently in the winter-dormant cunner (Tautogolabrus adspersus), inactivity and the passive physicochemical (Arrhenius) effect of cold on standard metabolic rate (SMR) are the common primary mechanisms underlying the low metabolic rates among winter-dormant fishes. Using automated video tracking, we investigated threshold temperatures for winter dormancy onset (major reductions in activity, increased sheltering and fasting) in four phylogenetically diverse teleost species reported to be winter dormant: cunner, pumpkinseed sunfish (Lepomis gibbosus), American eel (Anguilla rostrata) and mummichog (Fundulus heteroclitus). All species showed large activity and feeding reductions, but the magnitude of change and dormancy threshold temperature was species-specific. We propose that a continuum of overwintering responses exists among fishes from dormant to lethargic to active. The relationship between activity and metabolic rate was then measured using video-recorded automated respirometry during acute cooling and following cold acclimation in pumpkinseed, mummichog and eel. In all species, activity and metabolic rate were strongly correlated at all temperatures, and cooling caused reduced activity and metabolic rate. When variation in activity was controlled for across temperatures spanning the dormancy thresholds, the thermal sensitivity of metabolic rate including SMR indicated the predominance of passive physicochemical influences (mean Q10<3.5), rather than active MRD. Activity reductions and physicochemical slowing of metabolism owing to cold appear to be the primary energy-saving mechanisms in overwintering fishes.


Assuntos
Temperatura Baixa , Perciformes , Animais , Metabolismo Energético , Peixes/fisiologia , Perciformes/fisiologia , Estações do Ano , Temperatura
4.
J Exp Biol ; 225(Suppl_1)2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35258603

RESUMO

The gill is the primary site of ionoregulation and gas exchange in adult teleost fishes. However, those characteristics that benefit diffusive gas exchange (large, thin gills) may also enhance the passive equilibration of ions and water that threaten osmotic homeostasis. Our literature review revealed that gill surface area and thickness were similar in freshwater (FW) and seawater (SW) species; however, the diffusive oxygen (O2) conductance (Gd) of the gill was lower in FW species. While a lower Gd may reduce ion losses, it also limits O2 uptake capacity and possibly aerobic performance in situations of high O2 demand (e.g. exercise) or low O2 availability (e.g. environmental hypoxia). We also found that FW fishes had significantly higher haemoglobin (Hb)-O2 binding affinities than SW species, which will increase the O2 diffusion gradient across the gills. Therefore, we hypothesized that the higher Hb-O2 affinity of FW fishes compensates, in part, for their lower Gd. Using a combined literature review and modelling approach, our results show that a higher Hb-O2 affinity in FW fishes increases the flux of O2 across their low-Gd gills. In addition, FW and SW teleosts can achieve similar maximal rates of O2 consumption (MO2,max) and hypoxia tolerance (Pcrit) through different combinations of Hb-O2 affinity and Gd. Our combined data identified novel patterns in gill and Hb characteristics between FW and SW fishes and our modelling approach provides mechanistic insight into the relationship between aerobic performance and species distribution ranges, generating novel hypotheses at the intersection of cardiorespiratory and ionoregulatory fish physiology.


Assuntos
Brânquias , Salinidade , Animais , Mineração de Dados , Peixes/fisiologia , Brânquias/metabolismo , Hipóxia/metabolismo , Oxigênio/metabolismo , Fenótipo , Água do Mar
5.
Proc Biol Sci ; 289(1971): 20212676, 2022 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-35317673

RESUMO

As climate warms, tropical species are expanding their distribution to temperate ecosystems where they are confronted with novel predators and habitats. Predation strongly regulates ecological communities, and range-extending species that adopt an effective antipredator strategy have a higher likelihood to persist in non-native environments. Here, we test this hypothesis by comparing various proxies of antipredator and other fitness-related behaviours between range-extending tropical fishes and native-temperate fishes at multiple sites across a 730 km latitudinal range. Although some behavioural proxies of risk aversion remained unaltered for individual tropical fish species, in general they became more risk-averse (increased sheltering and/or flight initiation distance), and their activity level decreased poleward. Nevertheless, they did not experience a decline in body condition or feeding rate in their temperate ranges. Temperate fishes did not show a consistently altered pattern in their behaviours across range locations, even though one species increased its flight initiation distance at the warm-temperate location and another one had lowest activity levels at the coldest range location. The maintenance of feeding and bite rate combined with a decreased activity level and increased sheltering may be behavioural strategies adopted by range-extending tropical fishes, to preserve energy and maintain fitness in their novel temperate ecosystems.


Assuntos
Antozoários , Ecossistema , Animais , Mudança Climática , Recifes de Corais , Peixes/fisiologia
6.
Cells ; 11(5)2022 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-35269447

RESUMO

Groupers are widely distributed in tropical and subtropical areas worldwide, are key species to coastal ecosystems, and valuable fishery targets. To facilitate artificial seed production technology for grouper aquaculture, the mechanisms of reproduction and gonad development are being elucidated for these important species. In addition, since groupers are sexually dimorphic fish with female-first maturity (protogynous hermaphrodite fish), research is being conducted to clarify the ecological mechanism of sex change and their reproductive physiology, focusing on the endocrine system. In recent years, research on groupers has also been conducted to understand changes in the coastal environment caused by ocean warming and man-made chemicals. However, due to difficulties associated with conducting research using wild populations for breeding experiments, knowledge of the physiology and ecology of these fish is lacking, especially their reproductive physiology. In this review, we present information on the reproductive physiology and endocrinology of groupers obtained to date, together with the characteristics of their life history.


Assuntos
Ecossistema , Processos de Determinação Sexual , Animais , Feminino , Peixes/fisiologia , Gônadas , Humanos , Reprodução/fisiologia , Diferenciação Sexual
7.
Artigo em Inglês | MEDLINE | ID: mdl-35331911

RESUMO

The evolutionary and ontogenetic changes from water- to air-breathing result in major changes in the cardiorespiratory systems. However, the potential changes in hemoglobin's (Hb) oxygen binding properties during ontogenetic transitions to air-breathing remain poorly understood. Here we investigated Hb multiplicity and O2 binding in hemolysates and Hb components from juveniles and adults of the obligate air-breathing pirarucu (Arapaima gigas) that starts life as water-breathing hatchlings. Contrasting with previous electrophoresis studies that report one or two isoHbs in adults, isoelectric focusing (IEF) resolved the hemolysates from both stages into four major bands, which exhibited identical O2 binding properties (i.e. O2 affinities, cooperativity coefficients, and sensitivities to pH and the major organic phosphate effectors), also as compared to the cofactor-free hemolysates. Of note, the multiplicity pattern recurred upon reanalyses of the most-abundant fractions isolated from the juvenile and the adult stages, suggesting possible stabilization of different quaternary states with different isoelectric points during the purification procedure. The study demonstrates unchanged Hb-O2 binding properties during development, despite the pronounced differences in O2 availability between the two media, which harmonizes with findings based on a broader spectrum of interspecific comparisons. Taken together, these results disclose that obligate air-breathing in Arapaima is not contingent upon changes in Hb multiplicity and O2 binding characteristics.


Assuntos
Brânquias , Oxigênio , Animais , Peixes/fisiologia , Brânquias/metabolismo , Hemoglobinas/metabolismo , Oxigênio/metabolismo , Água/metabolismo
8.
PLoS One ; 17(3): e0265218, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35294467

RESUMO

Using a system optimized for propagating human keratinocytes, culture of skin samples from white and green sturgeons generated epithelial cells capable of making cross-linked protein envelopes. Two distinct forms of TGM1-like mRNA were molecularly cloned from the cells of white sturgeon and detected in green sturgeon cells, accounting for their cellular envelope forming ability. The protein translated from each displayed a cluster of cysteine residues resembling the membrane anchorage region expressed in epidermal cells of teleosts and tetrapods. One of the two mRNA forms (called A) was present at considerably higher levels than the other (called B) in both species. Continuous lines of white sturgeon epidermal cells were established and characterized. Size measurements indicated that a substantial fraction of the cells became enlarged, appearing similar to squames in human epidermal keratinocyte cultures. The cultures also expressed CYP1A, a cytochrome P450 enzyme inducible by activation of aryl hydrocarbon receptor 2 in fish. The cells gradually improved in growth rate over a dozen passages while retaining envelope forming ability, TGM1 expression and CYP1A inducibility. These cell lines are thus potential models for studying evolution of fish epidermis leading to terrestrial adaptation and for testing sturgeon sensitivity to environmental stresses such as pollution.


Assuntos
Peixes , Transglutaminases , Animais , Células Epidérmicas , Peixes/fisiologia , RNA Mensageiro/metabolismo , Transglutaminases/genética , Transglutaminases/metabolismo
9.
J Fish Biol ; 100(4): 958-969, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35229303

RESUMO

Anisakidae nematode larvae is one of the most common parasites in wild anadromous Coilia nasus. This study aims to explore the mechanism of the C. nasus immune response to the parasitism of Anisakid nematode larvae. Results found that Anisakid nematode larvae parasitism caused liver injury as evidenced by histomorphology results as well as high levels of aminotransferase and aspertate aminotransferase. Furthermore, Anisakid nematode larvae parasitism induced an immune response in the host, which was characterized by the elevated populations of macrophages and neutrophils in the liver and head-kidney in the Anisakidae-infected group compared to the noninfected group. The expression of immunoglobulin IgM and IgD in the liver and head-kidney was also increased in the Anisakidae-infected group. The Anisakidae-infected group showed higher activity of antioxidant enzymes catalase and superoxide dismutase, which indicates severe oxidative stress, and increased production of pro-inflammatory cytokines, TNF-α, IL-6 as well as MCP-1 in the liver compared with the noninfected group. As a result of inflammation, livers of hosts in the Anisakidae-infected group showed fibrosis, and elevated expression of associated proteins including α-smooth muscle actin, fibronectin, collagen type I and type III compared with the noninfected group. We demonstrated that Anisakid nematode larvae parasitism results in injury and fibrosis in the liver, and triggers immune cell infiltration and inflammation in the liver and head-kidney of C. nasus. Altogether, the results provide a foundation for building an interaction between parasite and host, and will contribute to C. nasus population and fishery resource protection.


Assuntos
Proteínas de Peixes , Peixes , Animais , Fibrose , Proteínas de Peixes/metabolismo , Peixes/fisiologia , Imunidade , Inflamação/metabolismo , Larva/metabolismo , Fígado/metabolismo , Cirrose Hepática/metabolismo , Transaminases/metabolismo
10.
J Acoust Soc Am ; 151(1): 205, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35105040

RESUMO

There are substantial knowledge gaps regarding both the bioacoustics and the responses of animals to sounds associated with pre-construction, construction, and operations of offshore wind (OSW) energy development. A workgroup of the 2020 State of the Science Workshop on Wildlife and Offshore Wind Energy identified studies for the next five years to help stakeholders better understand potential cumulative biological impacts of sound and vibration to fishes and aquatic invertebrates as the OSW industry develops. The workgroup identified seven short-term priorities that include a mix of primary research and coordination efforts. Key research needs include the examination of animal displacement and other behavioral responses to sound, as well as hearing sensitivity studies related to particle motion, substrate vibration, and sound pressure. Other needs include: identification of priority taxa on which to focus research; standardization of methods; development of a long-term highly instrumented field site; and examination of sound mitigation options for fishes and aquatic invertebrates. Effective assessment of potential cumulative impacts of sound and vibration on fishes and aquatic invertebrates is currently precluded by these and other knowledge gaps. However, filling critical gaps in knowledge will improve our understanding of possible sound-related impacts of OSW energy development to populations and ecosystems.


Assuntos
Ecossistema , Vento , Animais , Peixes/fisiologia , Invertebrados , Pesquisa , Som , Vibração
11.
Fish Physiol Biochem ; 48(2): 419-436, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35184249

RESUMO

In 1996, kiss was reported to regulate feeding in mammals, but studies are limited in fish. Our study aimed to explore the possible role of kiss in the regulation of feeding in Siberian sturgeon (Acipenser baerii). kiss1 and kiss2 were cloned, and the expression patterns were analyzed in Siberian sturgeon. The complete coding regions of kiss1 and kiss2 genes were 393 and 471 bp. Both kiss1 and kiss2 showed the highest expression level in the hypothalamus. During the periprandial and fasting experiments, the expression of kiss1 and kiss2 highly significantly increased in the hypothalamus after feeding (P < 0.01). Compared with the feeding group, in hypothalamus, kiss1 expression in the fasting group highly significantly decreased (P < 0.01). In contrast, kiss2 expression had no significant difference on days 1 and 7 (P > 0.05) but highly significantly increased on day 14 (P < 0.01). Subsequently, the feeding function was verified by intraperitoneal (i.p.) injection of Kp1(10) and Kp1(10) into fish. The results showed that i.p. injection of 1 µg/g BW Kp1(10) or 0.01 µg/g BW Kp2(10) could significantly reduce 0-1 h food intake (P < 0.05) and affected the expression levels of apelin, ghrelin, leptin, nmu, etc. in the hypothalamus. These results suggested that kiss1 plays an anorexic role in both short- and long-term feeding regulation, while kiss2 plays a short-term anorexic and long-term orexigenic role. This study described kiss as a novel regulator of appetite in fish and laid the groundwork for further studies focused on physiological function. HIGHLIGHTS: • The kiss1 and kiss2 of Siberian sturgeon were cloned. • The expression levels of kiss1 and kiss2 mRNA were the highest in the hypothalamus. • Postprandial hypothalamic kiss1 and kiss2 expression levels increased in the periprandial experiment. • In the fasting test, the expression of hypothalamic kiss1 decreased after fasting, while the expression of kiss2 increased after fasting on the 14th day. • Siberian sturgeon food intake was reduced, and appetite factors expression levels in the hypothalamus were altered after intraperitoneal injection of Kp1(10) and Kp2(10).


Assuntos
Peixes , Kisspeptinas , Animais , Apetite/fisiologia , Clonagem Molecular , Peixes/fisiologia , Kisspeptinas/genética , Kisspeptinas/metabolismo , Mamíferos/genética , Mamíferos/metabolismo , RNA Mensageiro/metabolismo
12.
PLoS Biol ; 20(2): e3001529, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35176032

RESUMO

An animal that tries to remove a mark from its body that is only visible when looking into a mirror displays the capacity for mirror self-recognition (MSR), which has been interpreted as evidence for self-awareness. Conservative interpretations of existing data conclude that convincing evidence for MSR is currently restricted to great apes. Here, we address proposed shortcomings of a previous study on MSR in the cleaner wrasse Labroides dimidiatus, by varying preexposure to mirrors and by marking individuals with different colors. We found that (1) 14/14 new individuals scraped their throat when a brown mark had been provisioned, but only in the presence of a mirror; (2) blue and green color marks did not elicit scraping; (3) intentionally injecting the mark deeper beneath the skin reliably elicited spontaneous scraping in the absence of a mirror; (4) mirror-naive individuals injected with a brown mark scraped their throat with lower probability and/or lower frequency compared to mirror-experienced individuals; (5) in contrast to the mirror images, seeing another fish with the same marking did not induce throat scraping; and (6) moving the mirror to another location did not elicit renewed aggression in mirror-experienced individuals. Taken together, these results increase our confidence that cleaner fish indeed pass the mark test, although only if it is presented in ecologically relevant contexts. Therefore, we reiterate the conclusion of the previous study that either self-awareness in animals or the validity of the mirror test needs to be revised.


Assuntos
Comportamento Animal/fisiologia , Cognição/fisiologia , Peixes/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Visual/fisiologia , Animais , Percepção de Cores/fisiologia , Feminino , Comportamento Social
13.
PLoS Biol ; 20(2): e3001511, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35113875

RESUMO

Ocean acidification-decreasing oceanic pH resulting from the uptake of excess atmospheric CO2-has the potential to affect marine life in the future. Among the possible consequences, a series of studies on coral reef fish suggested that the direct effects of acidification on fish behavior may be extreme and have broad ecological ramifications. Recent studies documenting a lack of effect of experimental ocean acidification on fish behavior, however, call this prediction into question. Indeed, the phenomenon of decreasing effect sizes over time is not uncommon and is typically referred to as the "decline effect." Here, we explore the consistency and robustness of scientific evidence over the past decade regarding direct effects of ocean acidification on fish behavior. Using a systematic review and meta-analysis of 91 studies empirically testing effects of ocean acidification on fish behavior, we provide quantitative evidence that the research to date on this topic is characterized by a decline effect, where large effects in initial studies have all but disappeared in subsequent studies over a decade. The decline effect in this field cannot be explained by 3 likely biological explanations, including increasing proportions of studies examining (1) cold-water species; (2) nonolfactory-associated behaviors; and (3) nonlarval life stages. Furthermore, the vast majority of studies with large effect sizes in this field tend to be characterized by low sample sizes, yet are published in high-impact journals and have a disproportionate influence on the field in terms of citations. We contend that ocean acidification has a negligible direct impact on fish behavior, and we advocate for improved approaches to minimize the potential for a decline effect in future avenues of research.


Assuntos
Comportamento Animal/efeitos dos fármacos , Peixes/fisiologia , Concentração de Íons de Hidrogênio , Água do Mar/química , Animais , Viés , Recifes de Corais , Oceanos e Mares
14.
Sci Rep ; 12(1): 3164, 2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35210443

RESUMO

Longitudinal movement plays fundamental role in habitat colonization and population establishment of many riverine fish species. Movement patterns of amphidromous fish species at fine-scales that would allow characterizing the direction of movement and factors associated with the establishment of specific life-history strategies (resident or amphidromous) in rivers are still poorly understood. We assess fine-scale longitudinal movement variability patterns of facultative amphidromous fish species Galaxias maculatus in order to unfold its life-history variation and associated recruitment habitats. Specifically, we analyzed multi-elemental composition along core to edge transects in ear-bones (otoliths) of each fish using recursive partitions that divides the transect along signal discontinuities. Fine-scale movement assessment in five free-flowing river systems allowed us to identify movement direction and potential recruitment habitats. As such, resident recruitment of G. maculatus in freshwater (71%) and estuarine (24%) habitats was more frequent than amphidromous recruitment (5%), and was linked to availability of slow-flowing lotic or lentic habitats that produce or retain small-bodied prey consumed by their larvae. We postulate that life-history variation and successful recruitment of facultative amphidromous fish such as G. maculatus in river systems is driven by availability of suitable recruitment habitats and natural hydrologic connectivity that allows fish movement to these habitats.


Assuntos
Migração Animal , Comportamento Animal , Peixes/fisiologia , Osmeriformes/fisiologia , Animais , Ecossistema , Água Doce , Rios
15.
Vet Parasitol ; 303: 109667, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35124292

RESUMO

Trichodinids are problematic ectoparasites for intensive arapaima fish farming, which can make their breeding costly and unprofitable. The search for effective and safe therapeutic molecules is constant, and chloramine-T has stood out as an effective biocide to treat various pathogens in aquaculture. Here we investigated the acute toxicity (LC50-4h) of chloramine-T and its behavioural, morphological, histological, physiological, and antiparasitic effects on the control of trichodinids in arapaima juveniles. Initially arapaima were exposed to chloramine-T (0, 10, 20, 40, 50, 60, 80, 100 mg L-1) for 4 h. During this period, behavioural, morphological, and mortality changes were recorded. Immediately after a toxicity test, gills were collected for the histological analysis. The LC50-4h was calculated at 23.8 mg L-1 of chloramine-T. Behavioural changes like erratic swimming, loss of balance, gasping at the water surface, excessive mucus, jumping at the water surface, lethargy and gill hyperventilation, and morphological changes like loss of scales, ocular opacity, and skin darkening, were considered mild in arapaima exposed to 10 and 20 mg L-1 of chloramine-T for 4 h. The arapaima gills exposed to 10, 20 and, 40 mg L-1 of chloramine-T presented epithelial hyperplasia, dilated venous sinus and eosinophilic infiltrate, but they were reversible and of a low pathological degree. Based on the acute toxicity test (LC50-4h) results, concentrations were defined for the in vivo efficacy test, during which arapaima were exposed to 0, 10, 15, and 20 mg L-1 of chloramine-T for 1 h. After a therapeutic bath, physiological and parasitological analyses were performed. The use of 20 mg L-1 of chloramine-T significantly reduced (p < 0.05) parasitism by Trichodina sp. with an efficacy of 50.27 % and 53.23 % in gills and on the body surface, respectively. Chloramine-T did not change haematological parameters (erythrogram and thrombogram) or the biochemical parameters of arapaima after 1 h of exposure. However, monocytosis and neutrophilia were noted at slightly higher concentrations (15 and 20 mg L-1), but changes in fish homeostasis were not characterised. Thus, we demonstrate that the application of a therapeutic bath with 20 mg L-1 of chloramine-T for 1 h reduces parasitism by trichodinids and does not affect general arapaima juvenile health.


Assuntos
Peixes , Brânquias , Animais , Aquicultura , Cloraminas , Peixes/anatomia & histologia , Peixes/fisiologia , Brânquias/parasitologia , Compostos de Tosil
16.
Mar Environ Res ; 175: 105568, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35134639

RESUMO

High quality nursery grounds are important for species success and the long-term sustainability of fish stocks. However, even for important fisheries species, what constitutes nursery habitats is only coarsely defined, and details of specific requirements are often lacking. In this study we investigated upstream estuarine areas in central Queensland, Australia, to identify the environmental factors that constrain nursery ground utilization for important fisheries species. We used unbaited underwater video cameras to assess fish presence, and used a range of water quality sensors to record fluctuations in environmental conditions, likely to influence juveniles, over several months (e.g. tidal connection patterns, temperature, salinity and dissolved oxygen). We found that juveniles of three fisheries target species (Lutjanus argentimaculatus, Lutjanus russellii and Acanthopagrus australis) were common in the upstream sections of the estuaries. For each species, only a subset of the factors assessed were influential in determining nursery ground utilization, and their importance varied among species, even among the closely related L. argentimaculatus and L. russellii. Overall, tidal connectivity and the availability of complex structure, were the most influential factors. The reasons for the importance of connectivity are complex; as well as allowing access, tidal connectivity influences water levels, water temperature and dissolved oxygen - all important physiological requirements for successful occupation. The impact of variation in juvenile access to food and refuge in nursery habitat was not directly assessed. While crucial, these factors are likely to be subordinate to the suite of environmental characteristics necessary for the presence and persistence of juveniles in these locations. These results suggest that detailed environmental and biological knowledge is necessary to define the nuanced constraints of nursery ground value among species, and this detailed knowledge is vital for informed management of early life-history stages.


Assuntos
Ecossistema , Estuários , Animais , Austrália , Pesqueiros , Peixes/fisiologia
17.
Science ; 375(6581): 639-647, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35143298

RESUMO

Biohybrid systems have been developed to better understand the design principles and coordination mechanisms of biological systems. We consider whether two functional regulatory features of the heart-mechanoelectrical signaling and automaticity-could be transferred to a synthetic analog of another fluid transport system: a swimming fish. By leveraging cardiac mechanoelectrical signaling, we recreated reciprocal contraction and relaxation in a muscular bilayer construct where each contraction occurs automatically as a response to the stretching of an antagonistic muscle pair. Further, to entrain this closed-loop actuation cycle, we engineered an electrically autonomous pacing node, which enhanced spontaneous contraction. The biohybrid fish equipped with intrinsic control strategies demonstrated self-sustained body-caudal fin swimming, highlighting the role of feedback mechanisms in muscular pumps such as the heart and muscles.


Assuntos
Fenômenos Biomecânicos , Contração Muscular , Músculos/fisiologia , Miócitos Cardíacos/fisiologia , Nadadeiras de Animais/fisiologia , Animais , Biomimética , Biofísica , Peixes/fisiologia , Humanos , Robótica , Natação , Engenharia Tecidual
18.
PLoS One ; 17(2): e0264055, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35176093

RESUMO

Despite research and public scrutiny over recent decades, discarding continues to be an issue for trawl fisheries. Previous research demonstrates that environmental, biological, operational, legislative and socioeconomic drivers affect a fisher's decision to discard an organism. Therefore, the reduction of fishery discards requires a better understanding of fishery-specific drivers. Despite considerable research and mitigation, further work is required to reduce discarding to acceptable levels (currently ~ 50% in Australia). To better understand the drivers of discarding, this study used a modelling approach to determine environmental and operational factors that drive discarding in the New South Wales (NSW) ocean prawn trawl fishery (OPT). Further, the study investigated the relationship between the discarded number of individuals from all functional species groups (i.e. elasmobranchs, crustaceans and fish combined) and the retained catch weight. This model was also run on just fish partly due to their disproportionally high contribution to the discard assemblage (e.g. 76% of all species or higher taxon) and importance (e.g. to the ecosystem and fisheries). The results quantified relationships of environmental and operational drivers of discarding and the relationship of fish discarding and retained catch weight was found to be linear. However, the identified relationships appear complicated and, whilst an important first step, more work is required to identify all drivers influencing discarding practices. We, in combination with previous research, suggest implementation of effort quotas may be a suitable management initiative to reduce discarding and its impact; at least whilst more research is conducted to better understand this complex process. Furthering our understanding of discarding is urgent given its global impact and the rate of discarding in the OPT.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Pesqueiros/normas , Peixes/fisiologia , Modelos Estatísticos , Animais , Austrália , Dinâmica Populacional
19.
J Fish Biol ; 100(4): 979-987, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35076096

RESUMO

Cold water pollution (CWP) is caused by releases of unseasonably cold water from large, thermally stratified dams. Rapid and prolonged decreases in water temperature can have depressive effects on the metabolism, growth and swimming performance of fish. However, it is unknown if reducing the rate of temperature decrease could mitigate these negative effects by allowing thermal acclimation/acclimatization to occur. This study investigated the rate of temperature decrease as a potential CWP mitigation strategy in juvenile Murray cod Maccullochella peelii. M. peelii were exposed to a gradual, intermediate or rapid temperature decrease from 24 to 14°C. Energetic costs, locomotor performance, growth and survival were measured to determine if the initial thermal regime affected the thermal acclimation capacity of M. peelii. Cold exposure had significant acute and lasting depressive effects regardless of the rate of temperature decrease, although M. peelii showed varying degrees of thermal compensation in swimming performance and metabolism after 8 weeks of exposure to low temperatures. The short-term effects of CWP-like reductions in temperature are significant, but over time M. peelii can offset some of the depressive effects of CWP through thermal plasticity. This study highlights the importance of understanding physiological responses of fish to inform management and conservation. We conclude that rate of water temperature decline cannot be used to mitigate the sublethal effects of CWP on juvenile M. peelii but may still be useful for managing the negative effects in other native Australian fish species.


Assuntos
Peixes , Água , Aclimatação/fisiologia , Animais , Austrália , Temperatura Baixa , Peixes/fisiologia , Temperatura , Poluição da Água
20.
Artigo em Inglês | MEDLINE | ID: mdl-35031832

RESUMO

As the largest and most diverse vertebrate group on the planet, fishes have evolved an impressive array of sensory abilities to overcome the challenges associated with navigating the aquatic realm. Among these, the ability to detect Earth's magnetic field, or magnetoreception, is phylogenetically widespread and used by fish to guide movements over a wide range of spatial scales ranging from local movements to transoceanic migrations. A proliferation of recent studies, particularly in salmonids, has revealed that fish can exploit Earth's magnetic field not only as a source of directional information for maintaining consistent headings, but also as a kind of map for determining location at sea and for returning to natal areas. Despite significant advances, much about magnetoreception in fishes remains enigmatic. How fish detect magnetic fields remains unknown and our understanding of the evolutionary origins of vertebrate magnetoreception would benefit greatly from studies that include a wider array of fish taxa. The rich diversity of life-history characteristics that fishes exhibit, the wide variety of environments they inhabit, and their suitability for manipulative studies, make fishes promising subjects for magnetoreception studies.


Assuntos
Migração Animal , Peixes , Migração Animal/fisiologia , Animais , Peixes/fisiologia , Humanos , Campos Magnéticos , Magnetismo , Sensação
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