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1.
Environ Monit Assess ; 192(11): 698, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33044609

RESUMO

Environmental monitoring guides conservation and is particularly important for aquatic habitats which are heavily impacted by human activities. Underwater cameras and uncrewed devices monitor aquatic wildlife, but manual processing of footage is a significant bottleneck to rapid data processing and dissemination of results. Deep learning has emerged as a solution, but its ability to accurately detect animals across habitat types and locations is largely untested for coastal environments. Here, we produce five deep learning models using an object detection framework to detect an ecologically important fish, luderick (Girella tricuspidata). We trained two models on footage from single habitats (seagrass or reef) and three on footage from both habitats. All models were subjected to tests from both habitat types. Models performed well on test data from the same habitat type (object detection measure: mAP50: 91.7 and 86.9% performance for seagrass and reef, respectively) but poorly on test sets from a different habitat type (73.3 and 58.4%, respectively). The model trained on a combination of both habitats produced the highest object detection results for both tests (an average of 92.4 and 87.8%, respectively). The ability of the combination trained models to correctly estimate the ecological abundance metric, MaxN, showed similar patterns. The findings demonstrate that deep learning models extract ecologically useful information from video footage accurately and consistently and can perform across habitat types when trained on footage from the variety of habitat types.


Assuntos
Aprendizado Profundo , Monitoramento Ambiental , Animais , Ecossistema , Meio Ambiente , Peixes , Humanos
2.
Zootaxa ; 4775(1): zootaxa.4775.1.1, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33055597

RESUMO

This is an annotated checklist of the marine fish species of Lebanon (Levant coast, eastern Mediterranean). It comprises a total of 367 fish species distributed in 159 families and 27 orders, out of which 70 species are non-indigenous and 28 are recorded for the first time from Lebanon. The checklist includes all names and citations of species found in the literature, as well as references to specimens available in museum collections. It also includes an updated zoogeographic distribution and conservation status for each species. Threats were estimated based on surveys and observations made over the last two decades; broadly categorized conservation actions were also suggested.


Assuntos
Peixes , Animais , Líbano , Museus
3.
Zootaxa ; 4816(2): zootaxa.4816.2.5, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-33055705

RESUMO

Acanthemblemaria aceroi new species is described from the upwelling region of the Caribbean coasts of Venezuela and Colombia. It differs from its closest relative, Acanthemblemaria rivasi Stephens, 1970, known from Panama and Costa Rica, in the posterior extent of the infraorbitals, details of head spination, and unique COI sequences. The description of Acanthemblemaria johnsonsi Almany Baldwin, 1996, heretofore known only from Tobago, is expanded based on specimens from islands offshore of eastern Venezuela.


Assuntos
Peixes , Animais , Região do Caribe , América do Sul
4.
Zootaxa ; 4834(1): zootaxa.4834.1.8, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-33056136

RESUMO

Corcyrogobius pulcher sp. nov. is described from off Île de Ngor, Dakar, Senegal. Corcyrogobius pulcher is distinguished from its two congeners by having the rear edge of the jaws ending posteriorly below mideye, second dorsal fin I/9, pectoral fin rays 17, pelvic fins oval or truncated posteriorly, scales in lateral series 26-27, anterior oculoscapular head canal with pore ß, suborbital row b of sensory papillae anteriorly beginning below vertical of posterior edge of eye, dark vertical caudal bar, branchiostegal membrane without intense dark spot, cheek with two oblique whitish stripes, the first going from the eye downwards and forward to the posterior jaws, the second on the preopercular, alternating with brown oblique stripe going from behind the eye downwards and forward across the cheek. Furthermore, mitochondrial COI-barcoding data unambiguously support the species-level distinctiveness of the three Corcyrogobius species. A key to the species of Corcyrogobius is provided.


Assuntos
Perciformes , Animais , Peixes , Cabeça , Senegal
5.
Zootaxa ; 4852(5): zootaxa.4852.5.2, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-33056394

RESUMO

A taxonomic review of the Scorpaena papillosa species complex, defined here as having 10 dorsal-fin soft rays, coronal spines, and two upwardly directed spines on the lacrimal bone, resulted in the recognition of two species and two subspecies, Scorpaena papillosa (Schneider Forster, 1801) including two subspecies, i.e., S. papillosa papillosa (New Zealand) and S. papillosa ergastulorum Richardson, 1842a (southeastern Australia), and S. vesperalis n. sp. (southwestern Australia). Scorpaena p. papillosa and S. p. ergastulorum, are redescribed, with designation of a neotype for S. p. papillosa. Scorpaena vesperalis n. sp., described from coastal waters off southwestern Western Australia on the basis of 57 specimens, is characterized as follows: pectoral-fin rays 14-16; longitudinal scale rows 37-41; body depth 32.3-39.5 % of SL; upper-jaw length 19.6-22.5 % of SL; maxilla depth 5.7-7.3 % of SL; postorbital length 18.2-21.3 % of SL; least distance between interorbital ridges 1.4-2.7 % of SL; 1st anal-fin spine length 7.2-10.0 % of SL; anterior lacrimal spine simple, without additional small spinous points on its posterior margin; a single united pore behind the lower jaw symphysial knob; relatively large supraocular tentacle; all fins of preserved specimens usually uniformly whitish to translucent; and small body size (maximum recorded length 67.6 mm SL). The new species is likely endemic to southwestern Australia. Morphological ontogenetic changes in the relative lengths of some body proportions in the three taxa are also discussed.


Assuntos
Perciformes , Animais , Austrália , Peixes
6.
Zootaxa ; 4852(2): zootaxa.4852.2.4, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33056424

RESUMO

Two new species of miniature silverside fishes are described from coastal habitats in the tropical Atlantic: Membras pygmaea sp. nov., from Brus Lagoon, Honduras, and M. procera sp. nov., from the Gulf of Urabá, Colombia. These new species belong to the martinica species-group within the genus Membras Bonaparte. The monophyletic martinica species-group (see below) contains four additional species, all coastal, marine that extend from the east coast of North America to São Paolo State, Brazil. Within the martinica species-group, all but M. martinica are miniature species, ranging from 41-60 mm SL. The smallest species, M. pygmaea sp. nov., is mature at 24 mm SL. A geometric morphometric analysis shows: (i) each species of the martinica species-group occupies its own portion of shape space; and (ii) none of the miniature species possess the shapes of small immature M. martinica. While some of the literature suggests that miniaturization may involve paedomorphosis, our results show that the miniatures accelerate to adult body forms.


Assuntos
Peixes , Animais , Oceano Atlântico
7.
Zootaxa ; 4852(1): zootaxa.4852.1.8, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-33056713

RESUMO

The checklist by Robertson et al. (2017) of fishes from the tropical eastern Pacific included information on three members of the family Triglidae: Bellator loxias (Jordan, 1897), Prionotus ruscarius and P. stephanophrys Lockington, 1881. Unfortunately, the identification of four specimens as P. ruscarius is incorrect, as they are Bellator gymnostethus. We thank Benjamin Victor for bringing these misidentifications to our notice through his work with mtDNA sequence data from the Barcode of Life Database (BOLD: http://www.boldsystems.org). The photographs of the four specimens on the BOLD website clearly depict a Bellator species rather than a Prionotus. However, the photograph in the 2017 paper (Figure 75, page 78), is correctly identified and labelled as P. ruscarius, and this species was collected on the cruise of the Miguel Oliver discussed in Robertson et al. (2017), see Benavides Moreno et al. (2019). This correction brings the number of triglids collected on that cruise to four species.


Assuntos
Perciformes , Animais , DNA Mitocondrial , Peixes
8.
Zootaxa ; 4762(1): zootaxa.4762.1.1, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33056890

RESUMO

Eelpout species of the genus Lycenchelys Gill, 1884 recorded from Japanese waters are taxonomically revised. This study recognizes the following 11 species from Japanese waters as valid: Lycenchelys albomaculata Toyoshima, 1983, Lycenchelys aurantiaca Shinohara Matsuura, 1998, Lycenchelys hippopotamus Schmidt, 1950, Lycenchelys maculata Toyoshima, 1985, Lycenchelys makushok Fedorov Andriashev, 1993, Lycenchelys melanostomias Toyoshima, 1983, Lycenchelys rassi Andriashev, 1955, Lycenchelys remissaria Fedorov, 1995, Lycenchelys ryukyuensis Shinohara Anderson, 2007, Lycenchelys squamosa Toyoshima, 1983 and Lycenchelys tohokuensis Anderson Imamura, 2002. We redescribe species in detail based on type specimens as well as additional specimens in many cases. The synonymy of Lycenchelys brevimaxillaris Toyoshima, 1985 with L. melanostomias is supported in this study. Sexual dimorphism and changes with growth are revealed in L. albomaculata, L. aurantiaca, L. hippopotamus, L. makushok, L. melanostomias and L. rassi, all based on 10 or more specimens, for relative head length, head width, and upper and lower jaw lengths. In addition, we also found that the sizes at which sexual dimorphism can be recognized, and the tendencies for change with growth, differ among species. Furthermore, the dimorphism in head length is influenced by the snout length, eye diameter and/or postorbital length in L. albomaculata and L. aurantiaca.


Assuntos
Perciformes , Animais , Peixes , Japão , Mandíbula , Caracteres Sexuais
9.
Sci Total Environ ; 741: 140527, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32886999

RESUMO

Pollution with microplastics has become an environmental concern worldwide. Yet, little information is available on the distribution of microplastics in lakes. Lake Ziway is one of the largest lakes in Ethiopia and is known for its fishing and drinking water supply. This study aims to examine the distribution of plastic particles, of all sizes (micro- and small macro-plastics) in four of the major fish species of the lake and in its shoreline sediment. The gastrointestinal tracts analysis showed that 35% of the sampled fishes ingested plastic particles. The median number of particles per fish was 4 (range 1-26). Benthic (Clarias gariepinus) and benthopelagic (Cyprinus carpio and Carassius carassius) fish species were found to contain a significantly higher number of plastic particles in comparison to the planktivorous fish species (Oreochromis niloticus). More fishes ingested plastic particles in the wet compared to the dry season. The maximum plastic size (40 mm fibre) was found in C. carpio. Estimated median mass of plastic particles in fish was 0.07 (0.0002-385.2) mg/kg_ww. Fish and sediment samples close to known potential sources of plastic particles had a higher plastic ingestion frequency (52% of the fish) and higher plastic concentration compared to the other parts of the lake. The median count and mass of plastic particles measured in sediment of the lake were 30,000 (400-124,000) particles/m3 and 764 (0.05-36,233) mg/kg_dw, respectively, the upper limits of which exceed known effect thresholds. Attenuated total reflection (ATR) - Fourier-transform infrared (FTIR) spectroscopy showed that polypropylene, polyethylene and alkyd-varnish were the dominant polymers in fishes and in sediment. The plastic particles size distributions were Log-linear and were identical for plastic particles found in fish and in sediment, suggesting strong benthic-pelagic coupling of plastic particles transfer.


Assuntos
Carpas , Poluentes Químicos da Água/análise , Animais , Monitoramento Ambiental , Etiópia , Peixes , Lagos , Microplásticos , Plásticos
10.
Mar Pollut Bull ; 159: 111450, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892911

RESUMO

Marine noise pollution (MNP) can cause a multitude of impacts on many organisms, but information is often scattered and general outcomes difficult to assess. We have reviewed the literature on MNP impacts on Mediterranean fish and invertebrates. Both chronic and acute MNP produced by various human activities - e.g. maritime traffic, pile driving, air guns - were found to cause detectable effects on intra-specific communication, vital processes, physiology, behavioral patterns, health status and survival. These effects on individuals can extend to inducing population- and ecosystem-wide alterations, especially when MNP impacts functionally important species, such as keystone predators and habitat forming species. Curbing the threats of MNP in the Mediterranean Sea is a challenging task, but a variety of measures could be adopted to mitigate MNP impacts. Successful measures will require more accurate information on impacts and that effective management of MNP really becomes a priority in the policy makers' agenda.


Assuntos
Ecossistema , Ruído , Animais , Peixes , Humanos , Invertebrados , Mar Mediterrâneo
11.
Environ Monit Assess ; 192(9): 613, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32875407

RESUMO

Many environmental monitoring programs include an assessment of the health of fish populations using a sentinel species and include an indicator of reproductive potential. Knowledge of the reproductive strategy of the fish species is critical for data interpretation but is not always known. The reproductive strategy of a species can be determined from detailed histological analyses of ovaries throughout the reproductive cycle; however, these studies can be costly and can delay the implementation of a monitoring program. Three quick and cost-effective methods of predicting the reproductive strategy (annual single spawning or annual multiple spawning) are evaluated in this study using predicted probabilities from binary logistic regression models as a means of classifying the reproductive strategies of 18 different fish species in Atlantic Canada. The first method was based on the hypothesis that the variability in the ovary weight-body weight relationship in prespawning females is higher in multiple spawners. This method did not have a good classification rate due to some multiple spawners having low variability. The other two methods involved predictor variables representing the proportion of oocytes in different stages of development and predictor variables representing the distribution of oocyte sizes during the prespawning season for 111 fish (25 different samples for species). Predicted probabilities from these regression models could be used to correctly classify the reproductive strategies of all 25 samples (development stage model) and all but one sample (oocyte size distribution model). These models can be used to estimate the reproductive strategy of a species from a single sample of fish collected during the prespawning period to support species selection and data interpretation in environmental monitoring programs.


Assuntos
Monitoramento Ambiental , Reprodução , Animais , Canadá , Feminino , Peixes , Ovário
12.
Environ Monit Assess ; 192(10): 647, 2020 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-32948923

RESUMO

The energy transfer in the aquatic food chain is an important way for mercury (Hg) to enter other trophic levels. The objective of this work was to evaluate the Hg concentrations in plankton upstream and downstream of the Samuel Hydroelectric Reservoir, Rondônia, Brazil. Phytoplankton and zooplankton samples were collected with 20-µm and 68-µm nylon nets. An aliquot was removed for taxonomic analysis and another for total mercury determination, performed by cold vapor atomic absorption spectroscopy. Water physical-chemical parameters were also measured. The Hg concentrations in total plankton (phytoplankton and zooplankton samples) obtained at the three sampling upstream stations showed the same behavior, with the highest values registered in June 2005 (232 µg kg-1, 118 µg kg-1, 128 µg kg-1). The lowest values at stations J1 and M1 were recorded in November 2005 (4 µg kg-1 and 22 µg kg-1, respectively), while the lowest values at stations M4 and M8 were recorded in October 2005 (22 µg kg-1 and 5 µg kg-1, respectively). The Hg results found in the plankton in this study corroborate the results of other recent studies in the same region. The statistical analyses revealed that Hg concentrations in plankton do not explain the distribution of these organisms at the four sampling stations of Samuel Reservoir. Graphical Abstract.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Plâncton
13.
Sci Total Environ ; 740: 139902, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927533

RESUMO

Freshwater fish communities are impacted by multiple pressures, determining loss of functional diversity and redundancy. Our aim was to disentangle the roles and relevancies of different pressures in shaping fish communities in small streams of the Po plain (North Italy). Long term trend (1998-2018) of functional diversity of 31 fish communities was assessed and modeled in respect to three potential pressures: temperature increase, intensity of exotic fish invasion, and habitat quality degradation. Ecological traits mostly influenced by the pressures were also identified. Reduction of functional richness mostly due to local extinction or contraction of cold adapted predators, such as salmonids, was linked to increasing temperatures. Warming probably also led to a shift of generalist and dominant species, which became more abundant in streams hosting mixed communities of salmonids and cyprinids, and determined the increase of functional dispersion and uniqueness. Reduction of functional redundancy and increasing functional dispersion were both also related to the introduction of new ecological traits brought by expanding exotic species. Low functional overlap was found among native and exotic species, indicating that the invasion process was mainly controlled by competitive interactions and/or resource opportunism. Functional response to habitat quality was not clearly evident. In conclusion, the impact of temperature increase and exotic species on fish functional diversity was effective, idiosyncratic and mediated by the scale of analysis and by the intensity of pressures.


Assuntos
Biodiversidade , Cyprinidae , Animais , Ecossistema , Peixes , Água Doce , Itália
14.
Sci Total Environ ; 740: 140140, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927548

RESUMO

This study proposed a framework (termed as "nanoHealthRisk" hereafter) for incorporating i) interaction of nanoparticles (NPs) with fishes, ii) availability of NPs to the human digestive system, and iii) estimation of health risk due to fish consumption and inadvertent ingestion of NP-contaminated surface water, for the first time as per the literature review. The framework was applied for estimating health risks due to hypothetical exposures of pristine ZnO, CuO, and TiO2 NPs (without any surface functionalization) from fish tissues. Values of bio- concentration factors (BCF) of ZnO, CuO, and TiO2 NPs in fish and model distributions of bio-assimilation factor of ZnO, CuO and TiO2 NPs in the human digestive system were incorporated explicitly in the risk assessment of NPs for the first time. ZnO NP was observed to be transferred more to the human digestive system from aqueous matrix than the other two NPs. Maximum allowable values of NP posing no risk were found to be 0.115 mg/L, 0.152 mg/L, and 1.77 × 107 mg/L for pristine ZnO, CuO and TiO2 NP, respectively. At the environmental concentration range, exposures of studied NPs from aquatic environment under the assumptions used did not pose any health risk under the conditions studied in this study. More work is required to (1) Estimate bio-concentration factors of a mixture of NPs with other constituents in fish tissues, (2) Estimate dissolution of NP from fish tissue in human digestive media, (3) Generate new data to develop reference dose of NP for human health risk assessment, and (4) Study effect of NP fate in the water on health risk through fish consumption pathway. Until all above-mentioned aspects are not explicitly incorporated in the risk assessment framework, risk estimates do not represent the risk from environment completely. Thus, continuous monitoring of these NPs in the environment is required to protect health due to chronic exposure of small concentrations of NPs from an aqueous matrix.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Óxido de Zinco , Animais , Cobre , Peixes , Humanos , Água
15.
Proc Biol Sci ; 287(1935): 20201752, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32993472

RESUMO

Group living is a common strategy used by fishes to improve their fitness. While sociality is associated with many benefits in natural environments, including predator avoidance, this behaviour may be maladaptive in the Anthropocene. Humans have become the dominant predator in many marine systems, with modern fishing gear developed to specifically target groups of schooling species. Therefore, ironically, behavioural strategies which evolved to avoid non-human predators may now actually make certain fish more vulnerable to predation by humans. Here, we use an individual-based model to explore the evolution of fish schooling behaviour in a range of environments, including natural and human-dominated predation conditions. In our model, individual fish may leave or join groups depending on their group-size preferences, but their experienced group size is also a function of the preferences of others in the population. Our model predicts that industrial fishing selects against individual-level behaviours that produce large groups. However, the relationship between fishing pressure and sociality is nonlinear, and we observe discontinuities and hysteresis as fishing pressure is increased or decreased. Our results suggest that industrial fishing practices could be altering fishes' tendency to school, and that social behaviour should be added to the list of traits subject to fishery-induced evolution.


Assuntos
Pesqueiros , Peixes/fisiologia , Comportamento Social , Animais , Conservação dos Recursos Naturais , Seleção Genética
16.
Aquat Toxicol ; 227: 105615, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32932041

RESUMO

Chemical contaminants can be discharged by vessel hull cleaning processes, such as scraping, jet spraying, and painting, all of which produce readily transportable contaminants into the marine environment, where they are referred to as 'hotspots' of contamination in coastal areas. However, many countries have not yet established effective evaluation methods for disposal of waste mixtures or management guidelines for areas of hull cleaning. To define the toxic effects of wastewater from vessel hull cleaning in dry docks on resident non-target organisms, we investigated the chemical concentrations and developmental toxicity on embryonic flounder, which is an organism sensitive to chemical contamination. In this study, the dominant inorganic metal discharged was zinc when cleaning Ship A (300 tons) and copper for Ship B (5,000 tons). The wastewater from high-pressure water blasting (WHPB) of Ship A (300 tons) and Ship B (5,000 tons) produced a largely overlapping suite of developmental malformations including pericardial edema, spinal curvature, and tail fin defects. Forty-eight hours after exposure, the frequency percentage of malformation began to increase in embryos exposed to a 500-fold dilution of WHPB from Ships A and B. We performed transcriptome sequencing to characterize the toxicological developmental effects of WHPB exposure at the molecular level. The results of the analysis revealed significantly altered expression of genes associated with muscle cell differentiation, actin-mediated cell contraction, and nervous system development (cutoff P < 0.01) in embryonic flounder exposed to high-pressure cleaning effluent from Ship A. Genes associated with chromatin remodeling, cell cycling, and insulin receptor signaling pathways were significantly altered in embryonic flounder exposed to WHPB of Ship B (cutoff P < 0.01). These findings provide a greater understanding of the developmental toxicity and potential effects of WHPB effluent on coastal embryonic fish. Furthermore, our results could inform WHPB effluent management practices to reduce impacts on non-target coastal organisms.


Assuntos
Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/toxicidade , Animais , Incrustação Biológica , Peixes , Linguado , Metais , Navios , Águas Residuárias/química
17.
Aquat Toxicol ; 227: 105620, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32932042

RESUMO

The 20th Pollutant Responses in Marine Organisms (PRIMO 20) conference provided a forum for scientists from around the world to communicate novel toxicological research findings specifically focused on aquatic organisms, by combining applied and basic research at the intersection of environmental and mechanistic toxicology. The work highlighted in this special issue of Aquatic Toxicology, a special issue of Marine Environmental Research, and presented through posters and presentations, encompass important and emerging topics in freshwater and marine toxicology. This includes multiple types of emerging contaminants including microplastics and UV filtering chemicals. Other studies aimed to further our understanding of the effects of endocrine disrupting chemicals, pharmaceuticals, and personal care products. Further research presented in this virtual issue examined the interactive effects of chemicals and pathogens, while the final set of manuscripts demonstrates continuing efforts to combine traditional biomonitoring, data from -omic technologies, and modeling for use in risk assessment and management. An additional goal of PRIMO meetings is to address the link between environmental and human health. Several articles in this issue of Aquatic Toxicology describe the appropriateness of using aquatic organisms as models for human health, while the keynote speakers, as described in the editorial below, presented research that highlighted bioaccumulation of contaminants such as PFOS and mercury from fish to marine mammals and coastal human populations such as the Gullah/GeeChee near Charleston, South Carolina, USA.


Assuntos
Organismos Aquáticos/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/efeitos dos fármacos , Ecossistema , Disruptores Endócrinos , Monitoramento Ambiental , Poluentes Ambientais/farmacologia , Peixes , Água Doce , Humanos , Plásticos
18.
Proc Biol Sci ; 287(1935): 20201759, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32933439

RESUMO

Male-only parental care, while rare in most animals, is a widespread strategy within teleost fish. The costs and benefits to males of acting as sole carer are highly variable among fish species making it challenging to determine the selective pressures driving the evolution of male-only care to such a high prevalence. We conducted a phylogenetic meta-analysis to examine the costs and benefits of paternal care across fish species. We found no evidence that providing care negatively affects male condition. In contrast with other taxa, we also found limited evidence that male care has evolved as a strategy to improve offspring survival. Instead, we found that males already caring for a brood are preferred by females and that this preference is strongest in those species in which males work harder to care for larger broods. Thus, in fish, investment in offspring care does not constrain a male's mating success but rather augments it, suggesting that the relatively high prevalence of male-only care in fish may be in part explained by sexual selection through female preference for caring males.


Assuntos
Peixes , Comportamento Paterno , Comportamento Sexual Animal , Animais , Análise Custo-Benefício , Pai , Feminino , Masculino , Filogenia , Reprodução
19.
Proc Biol Sci ; 287(1935): 20192939, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32933441

RESUMO

Salamanders, frog tadpoles and diverse lizards have the remarkable ability to regenerate tails. Palaeontological data suggest that this capacity is plesiomorphic, yet when the developmental and genetic architecture of tail regeneration arose is poorly understood. Here, we show morphological and molecular hallmarks of tetrapod tail regeneration in the West African lungfish Protopterus annectens, a living representative of the sister group of tetrapods. As in salamanders, lungfish tail regeneration occurs via the formation of a proliferative blastema and restores original structures, including muscle, skeleton and spinal cord. In contrast with lizards and similar to salamanders and frogs, lungfish regenerate spinal cord neurons and reconstitute dorsoventral patterning of the tail. Similar to salamander and frog tadpoles, Shh is required for lungfish tail regeneration. Through RNA-seq analysis of uninjured and regenerating tail blastema, we show that the genetic programme deployed during lungfish tail regeneration maintains extensive overlap with that of tetrapods, with the upregulation of genes and signalling pathways previously implicated in amphibian and lizard tail regeneration. Furthermore, the lungfish tail blastema showed marked upregulation of genes encoding post-transcriptional RNA processing components and transposon-derived genes. Our results show that the developmental processes and genetic programme of tetrapod tail regeneration were present at least near the base of the sarcopterygian clade and establish the lungfish as a valuable research system for regenerative biology.


Assuntos
Peixes/fisiologia , Cauda/fisiologia , Animais , Extremidades/fisiologia , Filogenia , Regeneração/fisiologia
20.
Proc Biol Sci ; 287(1935): 20201456, 2020 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-32933449

RESUMO

To be effective, animal colour signals must attract attention-and therefore need to be conspicuous. To understand the signal function, it is useful to evaluate their conspicuousness to relevant viewers under various environmental conditions, including when visual scenes are cluttered by objects of varying colour. A widely used metric of colour difference (ΔS) is based on the receptor noise limited (RNL) model, which was originally proposed to determine when two similar colours appear different from one another, termed the discrimination threshold (or just noticeable difference). Estimates of the perceptual distances between colours that exceed this threshold-termed 'suprathreshold' colour differences-often assume that a colour's conspicuousness scales linearly with colour distance, and that this scale is independent of the direction in colour space. Currently, there is little behavioural evidence to support these assumptions. This study evaluated the relationship between ΔS and conspicuousness in suprathreshold colours using an Ishihara-style test with a coral reef fish, Rhinecanthus aculeatus. As our measure of conspicuousness, we tested whether fish, when presented with two colourful targets, preferred to peck at the one with a greater ΔS - from the average distractor colour. We found the relationship between ΔS and conspicuousness followed-- a sigmoidal function, with high ΔS colours perceived as equally conspicuous. We found that the relationship between ΔS and conspicuousness varied across colour space (i.e. for different hues). The sigmoidal detectability curve was little affected by colour variation in the background or when colour distance was calculated using a model that does not incorporate receptor noise. These results suggest that the RNL model may provide accurate estimates for perceptual distance for small suprathreshold distance colours, even in complex viewing environments, but must be used with caution with perceptual distances exceeding- -10 ΔS.


Assuntos
Escamas de Animais/fisiologia , Peixes/fisiologia , Animais , Percepção de Cores , Recifes de Corais , Pigmentação , Tetraodontiformes/fisiologia
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