scholarly journals Habitat partitioning, habits and convergence among coastal nektonic fish species from the São Sebastião Channel, southeastern Brazil

2010 ◽  
Vol 8 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Fernando Zaniolo Gibran
Keyword(s):  
Habitat Use ◽  
Fish Species ◽  
Body Shape ◽  
Scientific Literature ◽  
Morphological Diversity ◽  
The Body ◽  
Divergent Evolution ◽  
Southeastern Brazil ◽  
Ecological Performance ◽  
Intimate Link

Based on a fish survey and preliminary underwater observations, 17 "morphotypes" were identified that characterize the morphological diversity found within 27 nektonic fish species sampled at São Sebastião Channel. Such "morphotypes" were studied using an ecomorphological approach, with the intention to investigate similarities and differences in shape and habits. Underwater field observations were also performed, to verify if the lifestyle of these species, such as vertical occupation of the water column and the habitat use, are in accordance with their distribution in the morphospace. The results, complemented with data from scientific literature on the taxonomy and phylogenies of these species, allowed discussing some of the typical cases of convergent and divergent evolution. Some of the ecomorphological clusters had no phylogenetic support although this is probably due to the environmental conditions in which theirs members have evolved. The body shape and fins positions of a fish clearly influence its ecological performance and habitat use, corroborating the ecomorphological hypothesis on the intimate link between phenotype and ecology.

scholarly journals Functional modularity in lake-dwelling characin fishes of Mexico

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3851 ◽  
Author(s):  
Claudia Patricia Ornelas-García ◽  
Amando Bautista ◽  
Fabian Herder ◽  
Ignacio Doadrio
Keyword(s):  
Body Shape ◽  
Evolutionary Change ◽  
The Body ◽  
Divergent Evolution ◽  
X Rays ◽  
Skull Shape ◽  
Sex Effects ◽  
Modular Evolution ◽  
Variation Patterns ◽  
Independent Variation

Modular evolution promotes evolutionary change, allowing independent variation across morphological units. Recent studies have shown that under contrasting ecological pressures, patterns of modularity could be related to divergent evolution. The main goal of the present study was to evaluate the presence of modular evolution in two sister lacustrine species,Astyanax aeneusandA. caballeroi, which are differentiated by their trophic habits. Two different datasets were analyzed: (1) skull X-rays from 73 specimens (35A. aeneusand 38A. caballeroi) to characterize skull variation patterns, considering both species and sex effects. For this dataset, three different modularity hypotheses were tested, previously supported in other lacustrine divergent species; (2) a complete body shape dataset was also tested for four modularity hypotheses, which included a total of 196 individuals (110Astyanax aeneusand 86A. caballeroi). Skull shape showed significant differences among species and sex (P < 0.001), whereAstyanax caballeroispecies showed an upwardly projected mandible and larger preorbital region. For the skull dataset, the modularity hypothesis ranked first included three partitioning modules. While for the complete body dataset the best ranked hypothesis included two modules (head vs the rest of the body), being significant only forA. caballeroi.

scholarly journals Relationship between Body Shape and Food Habits of Fish from Three Reservoirs of Sri Lanka

2007 ◽  
Vol 20 (3) ◽  
Author(s):  
W.S. WELIANGE ◽  
U.S. AMARASINGHE
Keyword(s):  
Fish Species ◽  
Food Habits ◽  
Body Shape ◽  
Feeding Habits ◽  
The Body ◽  
Trophic Levels ◽  
Maximum Height ◽  
Body Proportions ◽  
Shape Indices ◽  
Logarithmic Relationship

In the present paper, an attempt is made to investigate whether the body shape indices can be used to predict food habits of fish species in three reservoir fish communities of Sri Lanka. The present analysis is based on the studies on food and feeding habits of fish species and their body shape indices in three Sri Lankan reservoirs, namely Minneriya, Udawalawe and Victoria. Body proportions of individual fish species were determined as P1 (= Maximum height of the body/ Maximum width of the body) and P2 (= Total length/ Maximum height of the body), which were found to be negative curvilinearly related. Trophic indices (Ti) of individual fish species were determined on the basis of trophic level of each food item and the fractions of all food items consumed by fish species, which ranged from 1 for exclusively herbivorous species to 3 for carnivorous species. A negative logarithmic relationship between P1 and Ti indicates that laterally compressed fish species with deep bodies feed on lower trophic levels in the food web. On the other hand, dorso-ventrally flattened species with low P1 have higher trophic indices than those with high P1. The positive logarithmic relationship between P2 and Ti also indicates that short, deep-bodied fish species representing low P2 values feed on lower trophic levels whereas slender, long-bodied species with high P2 values feed on higher trophic levels. The body shapes, measured as simple body proportions of the definitions of P1 and P2, can therefore be used to predict feeding habits of fish.

scholarly journals The effect of locomotion mode on body shape evolution in teleost fishes

2021 ◽  
Author(s):  
Sarah T Friedman ◽  
Samantha A Price ◽  
Peter C Wainwright
Keyword(s):  
Body Shape ◽  
Morphological Diversity ◽  
The Body ◽  
Surprising Result ◽  
Teleost Fishes ◽  
Trade Offs ◽  
Straight Line ◽  
Swimming Mode ◽  
Body Shapes ◽  
The Impact

Abstract Teleost fishes vary in their reliance on median and paired fins (MPF) or undulation of the body (BCF) to generate thrust during straight-line, steady swimming. Previous work indicates that swimming mode is associated with different body shapes, though this has never been empirically demonstrated across the diversity of fishes. As the body does not play as active a mechanical role in steady swimming by MPF swimmers, this may relax constraints and spur higher rates of body shape diversification. We test these predictions by measuring the impact of the dominant steady swimming mode on the evolution of body shape across 2,295 marine teleost fishes. Aligning with historical expectations, BCF swimmers exhibit a more elongate, slender body shape, while MPF propulsion is associated with deeper and wider body shapes. However, in contrast to expectations, we find that BCF propulsion is associated with higher morphological diversity and greater variance around trait optima. This surprising result is consistent with the interpretation that stronger functional trade-offs stimulate phenotypic evolution, rather than constrain it.

scholarly journals Ecomorphology and use of food resources: inter- and intraspecific relationships of fish fauna associated with macrophyte stands

2016 ◽  
Vol 14 (4) ◽  
Author(s):  
Aline V. R. Prado ◽  
◽  
Erivelto Goulart ◽  
João P. A. Pagotto ◽  
◽  
...  
Keyword(s):  
Fish Species ◽  
Body Shape ◽  
Niche Breadth ◽  
Fish Fauna ◽  
Morphological Characteristics ◽  
Morphological Diversity ◽  
Food Resources ◽  
Trophic Niche ◽  
Eichhornia Azurea ◽  
The Relationship

ABSTRACT Based on the form-function interaction and its consequence to niche exploitation by fish species, the study aimed to identify ecomorphological patterns and to investigate the possibility of explaining the trophic niche breadth using the pattern of intraspecific ecomorphological diversity. We tested the following hypotheses: i) the morphology explains variations in diet among fish species; ii) the intraspecific ecomorphological diversity is related to the breadth of the trophic niche explored by the species, so that species that feed on a wider range of resources have greater variation in body shape compared to those specialized in resource consumption. Fish were collected in stands of the aquatic macrophytes Eichhornia azurea and Eichhornia crassipes in lentic environments of the Upper Paraná River floodplain, Brazil. Two major trends were observed in the morphological space: fish with body shapes adapted to explore the substrate and others with a design that facilitates the capture of food items in more structured habitats. The relationship of diet with body shape was confirmed by significant relationships between matrices of trophic and morphological distances, providing evidence that morphology is related to interspecific variations in the use of trophic resources. However, the ranges of morphological and intraspecific trophic variations were not significantly related, rejecting the second hypothesis about the relationship between intraspecific ecomorphological diversity and trophic niche breadth. The morphological characteristics often have multiple ecological roles, which could result in trade-off among these functions. Thus, fish with highly specialized morphology may show specialist feeding or even generalist habit, because in this case some resources may be difficult to exploit, even by a specialist. Species with low and high morphological diversity demonstrated narrow trophic niche and the availability of resources may have been essential for consumption. Therefore, species morphology is related to the use of food resources and ecomorphology can be considered an important tool for the prediction of the exploited niche space by species in assemblages. However it is not possible to predict if species with greater intraspecific morphological diversification indeed have wider niche, since the abundance or scarcity of the available food resources may interfere with trophic niche breadth.

scholarly journals Ecomorphological correlates of twenty dominant fish species of Amazonian floodplain lakes

2017 ◽  
Vol 77 (1) ◽  
pp. 199-206 ◽  
Author(s):  
F. K. Siqueira-Souza ◽  
C. Bayer ◽  
W. H. Caldas ◽  
D. C. Cardoso ◽  
K. C. Yamamoto ◽  
...  
Keyword(s):  
Habitat Use ◽  
Fish Species ◽  
Body Shape ◽  
Abundant Species ◽  
Floodplain Lakes ◽  
Swimming Ability ◽  
Dominant Fish ◽  
Solimões River

Abstract Fishes inhabiting Amazonian floodplain lakes exhibits a great variety of body shape, which was a key advantage to colonize the several habitats that compose these areas adjacent to the large Amazon rivers. In this paper, we did an ecomorphological analysis of twenty abundant species, sampled in May and August 2011, into two floodplain lakes of the lower stretch of the Solimões River. The analysis detected differences among species, which could be probably associated with swimming ability and habitat use preferences.

Modeling cetacean habitat use in an urban coastal area in southeastern Brazil

2020 ◽  
Vol 642 ◽  
pp. 227-240
Author(s):  
L Lodi ◽  
R Tardin ◽  
G Maricato
Keyword(s):  
Habitat Use ◽  
Protected Areas ◽  
Linear Models ◽  
Anthropogenic Activities ◽  
Buffer Zone ◽  
Humpback Whales ◽  
Southeastern Brazil ◽  
Major Influence ◽  
Cetacean Species ◽  
Few Data

Most studies of cetacean habitat use do not consider the influence of anthropogenic activities. We investigated the influence of environmental and anthropogenic variables on habitat use by humpback Megaptera novaeangliae and Bryde’s whales Balaenoptera brydei off the coast of the Brazilian city of Rio de Janeiro. Although there are 2 marine protected areas (MPAs) in this area, few data are available on cetacean habitat use or on the overlap of different cetacean species within these MPAs. Our aim was to evaluate the effectiveness of the MPAs and propose a buffer zone to better protect the biodiversity of the study area. We conducted systematic surveys and developed spatial eigenvector generalized linear models to characterize habitat use by the species in the study area. Habitat use by humpback whales was influenced only by depth, whereas for Bryde’s whales there was the additional influence of anthropogenic variables. For Bryde’s whales, which use the area for feeding, sea surface temperature and the distance to anchorages had a major influence on habitat use. We also showed that neither of the MPAs in the study area adequately protects the hotspots of either whale species. Most of the humpback whale grid cells with high sighting predictions were located within 2 km of the MPAs, while areas of high sighting prediction of Bryde’s whales were located up to 5 km from the MPAs, closer to beaches. Our findings provide important insights for the delimitation of protected areas and zoning of the MPAs.

CHARACTERISTICS OF FREE-RADICAL PROCESSES IN THE ORGANISMS OF SOME PREDATORY FISH SPECIES IN DIFFERENT SEASONS OF THE YEAR

2017 ◽  
pp. 117-123
Author(s):  
Nikolay Aleksandrovich Pudovkin ◽  
Peter Vladimirovich Smutnev
Keyword(s):  
Fish Species ◽  
Catalase Activity ◽  
Perca Fluviatilis ◽  
Selenium Concentration ◽  
The Body ◽  
Predatory Fish ◽  
Volga River ◽  
Silurus Glanis ◽  
Average Value ◽  
Pike Perch

The authors of the article have studied the content of the elements of anti-oxidant system (malondialdehyde, catalase, selenium) in tissues of the internal organs (gills, intestine, muscles, liver, swimbladder, scales) in some species of predatory fish (pike Esox lucius (L., 1758), perch Perca fluviatilis (L., 1758), pike-perch Sander lucioperca (L., 1758), catfish Silurus glanis ) widespread in the basin of the Volga river in the Saratov region. The lowest concentration of malondialdehyde in organisms of the studied fish species is observed in fall and winter; the highest - in spring and summer. Catalase activity in gills tissue of a pike raised in 11.8%, cat-fish - 9.1%, pike-perch - 7.5%, perch - 7.8%. In fall (compared to winter) enzyme activity lowering in gonads of pike-perch makes 16.3%, in gonads of perch - 14.4%. In other tissues there were not observed any evident changes of catalase activity. Fish species under consideration are listed according to the average value of selenium concentration in organisms, µg/g: pike (0.208) > catfish (0.207) > pike-perch (0.196) > perch (0.178). According to the average value of the selenium accumulation in the body in different season all the studied species can be placed in the following order, µg/g: winter-pike (0.132) > pike-perch (0.136) > perch and catfish (0.142); spring - pike-perch (0.190) > perch (0.191) > pike (0.208) > catfish (0.209); summer - perch (0.186) > pike-perch (0.190) > catfish and pike (0.203); autumn - perch (0.193) > pike-perch (0.268) > > catfish (0.274) > pike (0.289).

Updating long-held assumptions about fat stigma: For women, body shape plays a critical role

2020 ◽  
Author(s):  
Jaimie Krems ◽  
Steven L. Neuberg
Keyword(s):  
Body Shape ◽  
Critical Role ◽  
The Body ◽  
Theoretical Assumption ◽  
Obesity Stigma ◽  
Obese Female ◽  
Three Samples ◽  
Female Bodies ◽  
Different Parts ◽  
Fat Stigma

Heavier bodies—particularly female bodies—are stigmatized. Such fat stigma is pervasive, painful to experience, and may even facilitate weight gain, thereby perpetuating the obesity-stigma cycle. Leveraging research on functionally distinct forms of fat (deposited on different parts of the body), we propose that body shape plays an important but largely underappreciated role in fat stigma, above and beyond fat amount. Across three samples varying in participant ethnicity (White and Black Americans) and nation (U.S., India), patterns of fat stigma reveal that, as hypothesized, participants differently stigmatized equally-overweight or -obese female targets as a function of target shape, sometimes even more strongly stigmatizing targets with less rather than more body mass. Such findings suggest value in updating our understanding of fat stigma to include body shape and in querying a predominating, but often implicit, theoretical assumption that people simply view all fat as bad (and more fat as worse).

Chaos in body–vortex interactions

2010 ◽  
Vol 466 (2119) ◽  
pp. 1871-1891 ◽  
Author(s):  
Johan Roenby ◽  
Hassan Aref
Keyword(s):  
Body Shape ◽  
Mass Density ◽  
Relative Equilibrium ◽  
Large Body ◽  
Point Vortex ◽  
Cylindrical Body ◽  
The Body ◽  
Body Motion ◽  
Single Vortex ◽  
Vortex Interactions

The model of body–vortex interactions, where the fluid flow is planar, ideal and unbounded, and the vortex is a point vortex, is studied. The body may have a constant circulation around it. The governing equations for the general case of a freely moving body of arbitrary shape and mass density and an arbitrary number of point vortices are presented. The case of a body and a single vortex is then investigated numerically in detail. In this paper, the body is a homogeneous, elliptical cylinder. For large body–vortex separations, the system behaves much like a vortex pair regardless of body shape. The case of a circle is integrable. As the body is made slightly elliptic, a chaotic region grows from an unstable relative equilibrium of the circle-vortex case. The case of a cylindrical body of any shape moving in fluid otherwise at rest is also integrable. A second transition to chaos arises from the limit between rocking and tumbling motion of the body known in this case. In both instances, the chaos may be detected both in the body motion and in the vortex motion. The effect of increasing body mass at a fixed body shape is to damp the chaos.

scholarly journals Sea stars generate downforce to stay attached to surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mark Hermes ◽  
Mitul Luhar
Keyword(s):  
Body Shape ◽  
Control Volume ◽  
Water Channel ◽  
Morphological Plasticity ◽  
The Body ◽  
Sea Star ◽  
Sea Stars ◽  
Hydrodynamic Loads ◽  
Spherical Dome ◽  
Star Models

AbstractIntertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.

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