scholarly journals Use of food resources by the fish fauna of a small reservoir (rio Jordão, Brazil) before and shortly after its filling

2006 ◽  
Vol 4 (3) ◽  
pp. 357-362 ◽  
Author(s):  
Valdirene E. Loureiro-Crippa ◽  
Norma S. Hahn
Keyword(s):  
Food Supply ◽  
Fish Fauna ◽  
Stomach Contents ◽  
Detrended Correspondence Analysis ◽  
Food Resources ◽  
Limiting Factor ◽  
Trophic Groups ◽  
Small Reservoir ◽  
Risk Of Extinction ◽  
Before And After

The construction of dams brings about changes in the course of a river, which directly or indirectly affect the fish fauna. Alterations in the food resources available to the fish favor some species and deter others. In addition to the implications originating from damming, Jordão Reservoir has a characteristically large number of endemic species that, because of the impacts they have undergone, run the risk of extinction. In this study, we investigate the feeding flexibility of the fishes faced with alterations in the food supply through the assessment of the diet and trophic organization of the fish fauna (before and after the damming). Diet was determined analyzing 1,861 stomach contents from 27 fish species. Eight of this species were not caught after the damming. Detrended Correspondence Analysis (DCA) discriminated seven trophic groups. Omnivorous, insectivorous and invertivorous species had more temporal alterations in their diets. These changes altered the composition (in abundance and biomass) of the trophic groups, mainly after the damming. The detritivorous and piscivorous species maintained their diets during all study period. Analyses showed that about 75% of the species quickly changed their diets according to alterations in food supply. This implies that food is not a limiting factor (at first) for the maintenance of fish fauna of this reservoir, at least for the species that persisted after the filling.

scholarly journals Diet of a catfish before and after damming of the salto caxias reservoir, iguaçu river

2007 ◽  
Vol 50 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Rosilene Luciana Delariva ◽  
Norma Segatti Hahn ◽  
Luiz Carlos Gomes
Keyword(s):  
Significant Interaction ◽  
Life Stage ◽  
Stomach Contents ◽  
Detrended Correspondence Analysis ◽  
Diet Shift ◽  
Ontogenetic Diet Shift ◽  
Species Analysis ◽  
Before And After ◽  
High Degree ◽  
Iguaçu River

This study evaluated the diet of Pimelodus sp., before and after damming of Salto Caxias, (waterfall in the Iguaçu river), as well spatial and ontogenetic diet shift. Surveys were carried out from March 1997 to February 1998 (before damming) and from April 1999 to January 2000 (after damming) inside the reservoir and adjacent tributaries. Stomach contents analysis of 682 specimens revealed omnivory with high degree of trophic opportunism to this species. Analysis of variance (three way ANOVA) for scores produced from Detrended Correspondence Analysis (DCA) yielded a significant interaction between the damming phases and size of the individuals (juveniles and adults) (F = 4.68; P = 0.04). After damming, adults exploited mainly fish, whereas the juveniles fed mostly on plants, dipterans larvae and scales at different sites. From significant differences in the ordination among the factors considered, it could be inferred that the diet of Pimelodus sp. was influenced by the formation of the reservoir and this depended on the life stage considered. Position of the sites (feeding grounds) did not lead to significant alterations in diet.

scholarly journals Food resources sustaining the fish fauna in a section of the upper São Francisco River in Três Marias, MG, Brazil

2004 ◽  
Vol 64 (2) ◽  
pp. 195-202 ◽  
Author(s):  
M. C. C. Alvim ◽  
A. C. Peret
Keyword(s):  
Aquatic Invertebrates ◽  
Fish Fauna ◽  
Stomach Contents ◽  
Food Resources ◽  
Trophic Guilds ◽  
Terrestrial Invertebrates ◽  
Sao Francisco River ◽  
Seasonal Flooding ◽  
São Francisco River

With the purpose of determining the principal food resources responsible for maintaining the fishery yield in a section of the São Francisco River, 6 sampling of the fish fauna were made downstream from the Três Marias Dam, from September 1996 to July 1997. A total of 1,127 individuals of 35 species were captured, using gillnets with mesh sizes varying from 3 to 16 cm. The stomach contents of 33 species were examined in order to determine their diets. Five trophic guilds were established, in the following order of importance: ilyophagous, herbivorous, piscivorous, terrestrial invertebrates feeders, and aquatic invertebrates feeders. The resources sustaining the fish fauna were mainly of allochthonous origin. The ichthyonenosis appears to be mainly dependent on the detritus chain. The ciliary forest and seasonal flooding pulses are the main suppliers of food for the fish fauna.

scholarly journals Diet and trophic structure of the fish fauna in a subtropical ecosystem: impoundment effects

2013 ◽  
Vol 11 (4) ◽  
pp. 891-904 ◽  
Author(s):  
Rosilene Luciana Delariva ◽  
Norma Segatti Hahn ◽  
Elaine Antoniassi Luiz Kashiwaqui
Keyword(s):  
Trophic Structure ◽  
Feeding Habits ◽  
Spatial Scales ◽  
Fish Fauna ◽  
Stomach Contents ◽  
Trophic Guilds ◽  
Before And After ◽  
Temporal And Spatial ◽  
Nmds Analysis ◽  
Iguaçu River

This study examined the diet and trophic structure of the fish fauna, over temporal and spatial scales, as affected by the impoundment of the Iguaçu River in the region of Salto Caxias, Paraná State, Brazil. Sampling was conducted before (March 1997 - February 1998) and after the impoundment (March 1999 - February 2000), at four sampling sites. The stomach contents were analyzed by the volumetric method. The species could be organized in 10 trophic guilds: algivores, carcinophages, detritivores, herbivores, aquatic insectivores, terrestrial insectivores, invertivores, omnivores, piscivores, and planktivores; the first and last guilds were represented only in the post-impoundment period. Similarity patterns and feeding changes were summarized by a non-metric Multi-dimensional Scaling (nMDS) analysis and statistically tested by a Permutational multivariate analysis of variance (PERMANOVA). Most species showed feeding changes, except for the piscivores and detritivores. These changes were related to the temporal factor (impoundment phases), such as reduced intake of benthic organisms and allochthonous food, which were usually replaced by resources from the reservoir itself (algae, microcrustaceans, and fish), simplifying the food spectrum of the fish fauna. A different indicator of food resources (IndVal) corroborated these changes in the feeding of the species. The proportions of the trophic guilds evaluated based on the catch per unit of effort (CPUE) and tested by ANOSIM were significantly different before and after the impoundment. Herbivores and piscivores were the guilds that contributed (SIMPER) to these differences, especially the high increase in biomass of the piscivore guild after the impoundment. Variations in the abundance of trophic guilds were more directly related to changes in the feeding habits of the fish fauna than to increases in the number and biomass of the species that constitute these guilds.

scholarly journals Food spectrum and trophic structure of the ichthyofauna of Corumbá reservoir, Paraná river Basin, Brazil

2006 ◽  
Vol 4 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Karla D. G. Luz-Agostinho ◽  
Luis M. Bini ◽  
Rosemara Fugi ◽  
Angelo A. Agostinho ◽  
Horácio F. Júlio Jr.
Keyword(s):  
Fish Species ◽  
Trophic Structure ◽  
Environmental Changes ◽  
Stomach Contents ◽  
Trophic Groups ◽  
Trophic Plasticity ◽  
Before And After ◽  
Ordination Method ◽  
Temporal And Spatial ◽  
Terrestrial Insects

In this paper we evaluate plasticity of fish concerning diet. We expect that sampling over a large temporal and spatial scale, including environmental changes such as impoundments, will allow us to cover most of the diet plasticity. We also evaluate the efficacy of ordination method in discriminating trophic groups based on fish species diet. Data were obtained from 17 sampling stations sampled monthly from March/96 to February/99 in the Corumbá river drainage, before and after the formation of the Corumba reservoir. Diet was determined analysing 9,177 stomach contents from 64 fish species. Trophic categories were discriminated by a non-hierarchic grouping analysis named k-means, applied to diet data. Most of the species presented great trophic plasticity, eating a great variety of food items. Resources availability, estimated from all fish stomach contents, was similar among environments, except in creeks, where it varied more with a large importance of terrestrial insects. K-means present satisfactory results, identifying nine trophic groups (detritivores, herbivore-piscivores, insectivore-herbivores, omnivores, invertivores, aquatic insectivores, piscivore-insectivores, piscivores and herbivores).

Parathyroid gland before and after cisplatin treatment

1987 ◽  
Vol 45 ◽  
pp. 860-861
Author(s):  
S.K. Aggarwal ◽  
J.M. Fadool
Keyword(s):  
Parathyroid Gland ◽  
Wistar Rats ◽  
Antitumor Agent ◽  
The Body ◽  
Cross Linking ◽  
Limiting Factor ◽  
Hormonal Changes ◽  
Primary Mechanism ◽  
Before And After ◽  
Dna Strands

Cisplatin (CDDP) a potent antitumor agent suffers from severe toxic side effects with nephrotoxicity being the major dose-limiting factor, The primary mechanism of its action has been proposed to be through its cross-linking DNA strands. It has also been shown to inactivate various transport enzymes and induce hypocalcemia and hypomagnesemia that may be the underlying cause for some of its toxicities. The present is an effort to study its influence on the parathyroid gland for any hormonal changes that control calcium levels in the body.Male Swiss Wistar rats (Crl: (WI) BR) weighing 200-300 g and of 60 days in age were injected (ip) with cisplatin (7mg/kg in normal saline). The controls received saline injections only. The animals were injected (iv) with calcium (0.5 ml of 10% calcium gluconate/day) and were killed by decapitation on day 1 through 5. Trunk blood was collected in heparinized tubes.

scholarly journals Diet seasonality and food overlap of the fish assemblage in a pantanal pond

2008 ◽  
Vol 6 (4) ◽  
pp. 567-576 ◽  
Author(s):  
Gisele Caroline Novakowski ◽  
Norma Segatti Hahn ◽  
Rosemara Fugi
Keyword(s):  
Fish Assemblage ◽  
Food Resource ◽  
Fish Fauna ◽  
Diet Breadth ◽  
Food Resources ◽  
Dry Season ◽  
Trophic Guilds ◽  
Trophic Specialization ◽  
Mato Grosso ◽  
Mean Values

We assessed the trophic structure of the fish fauna in Sinhá Mariana pond, Mato Grosso State, from March 2000 to February 2001. The aim was to determine the feeding patterns of the fish species during the rainy and dry seasons. The diets of 26 species (1,294 stomach contents) were determined by the volumetric method. Insects and fish were the most important food resources: insects were the dominant food of 23% and 27% of the species, respectively, in the rainy and dry season, and fish was the dominant item for 31% of the species in both seasons. Cluster analysis (Euclidean Distance) identified seven trophic guilds in the rainy season (detritivores, herbivores, insectivores, lepidophages, omnivores, piscivores and planktivores), and five trophic guilds in the dry season (detritivores, insectivores, lepidophages, omnivores and piscivores). The smallest mean values of diet breadth were observed for the specialist guilds (detritivores, lepidophages and piscivores), in both seasons. The widest means for diet breadth were observed for the omnivores, regardless of the season. In general, there was no seasonal variation in feeding overlap among the species studied. At the community level, diet overlap values between species were low (< 0.4) for 80% of the pairs in each season, suggesting wide partitioning of the food resource. The fish assemblage showed a tendency toward trophic specialization, regardless of the season, although several species changed their diets. We might consider two non-excludent hypothesis: that there is no pattern on the use of seasonal food resources and/or probably there are several patterns, because each one is based on characteristics of the studied site and the taxonomic composition of the resident species.

scholarly journals EVALUACIÓN DE LOS RIESGOS DE AFECTACIÓN POR EL ESTABLECIMIENTO DE GRANJAS ATUNERAS EN RELACIÓN CON LA DISTRIBUCIÓN ESPACIAL DE CETÁCEOS EN EL GOLFO DULCE, COSTA RICA

2011 ◽  
Vol 1 ◽  
pp. 159 ◽  
Author(s):  
Lenin E. Oviedo Correa ◽  
Juan Diego Pacheco ◽  
David Herra Miranda
Keyword(s):  
Fish Fauna ◽  
Humpback Whales ◽  
Marine Biodiversity ◽  
Limiting Factor ◽  
Predator Population ◽  
Incidental Capture ◽  
Top Predators ◽  
Habitat Niche ◽  
Pass Through ◽  
Definition Of

Este estudio trata sobre la distribución espacial de depredadores marinos topes, particularmente cetáceos odontocetos y misticetos migratorios. Se describe el riesgo potencial de afectación por el establecimiento de instalaciones asociadas con operaciones locales de maricultura: jaulas de engorde para atún. Por medio de un enfoque teórico y empírico se establece cuantitativamente como la profundidad máxima, un factor limitante en la distribución y definición del nicho ecológico de cetáceos, se solaparía en valores con el área propuesta para el establecimiento de las jaulas, lo que induciría dos escenarios probables de afectación: el desplazamiento de las poblaciones de depredadores de un hábitat-nicho de alimentación potencial y la interacción progresiva entre los depredadores con la fauna acompañante alrededor de las instalaciones de la operación de cultivo, lo anterior implicaría un riesgo perenne de captura incidental de dichos depredadores. Adicionalmente, la presencia de ballenas jorobadas durante la temporada de lluvia en zonas aledañas a Punta Banco, se asociaría a una ruta migratoria desde las zonas de alimentación en Sudamérica-Antártica, que pasaría por el área proyectada para el establecimiento de la operación de maricultura. Los resultados ilustran la necesidad de seguir un principio precautorio y promover la reubicación de proyecto de maricultura en áreas de menor valor en términos de biodiversidad marina.This contribution deals with the spatial distribution of marine top predators, particularly odontocete and migratory misticete cetaceans. The study describes the potential risk of disturbances due to the establishment of mariculture operations and corresponding infrastructure: tuna feed lots. Through a mixed theoretical and empirical approach, this research corroborates how the maximum depth, a limiting factor in the definition of cetacean trophic niches off the study area, overlaps with the values for depths from an area proposed as the focal location of a tuna feed lot facility. The latter implies two particular scenarios: the translocation of the local predator population from a potential foraging habitat-niche, and the progressive negative interaction between predators and the accompanying fish fauna around of the cages, with a high probability of incidental capture of those predators by entanglement. Additionally, the occurrence of humpback whales during the rainy season associated with a migratory route from feeding grounds off Chile-Antarctica, that would pass through the area projected to harbor the mariculture operation. The results illustrate the need of considering a precautionary approach and relocate mariculture projects to areas of lesser value in terms of marine biodiversity.

scholarly journals Growth and mortality of black bass, Micropterus salmoides (Pisces, Centrachidae; Lacapède, 1802) in a reservoir in southern Brazil

2005 ◽  
Vol 65 (2) ◽  
pp. 363-369 ◽  
Author(s):  
U. H. Schulz ◽  
M. E. Leal
Keyword(s):  
Micropterus Salmoides ◽  
Scientific Information ◽  
Fish Fauna ◽  
Fish Diversity ◽  
First Year ◽  
Southern Brazil ◽  
Small Reservoir ◽  
Long Time ◽  
Black Bass ◽  
Aquaculture Facilities

The black bass, Micropterus salmoides, was introduced to Brazil from North America in 1922. Since then the species has been reared in aquaculture facilities intended to stock reservoirs as additions to native stocks available for angling. At present no scientific information on the biology of black bass in Brazilian waters is available. Since black bass dispersion may cause severe impacts on native Brazilian fish fauna, information on the basic biological parameters of this species is necessary. The objective of the present study is to provide information on the growth, age structure, and mortality of the species in a small reservoir in southern Brazil, where the species reproduces regularly. Based on scale readings, the von Bertalanffy growth curve was calculated and compared to the length-frequency distribution of the population. Both methods showed similar results. Maximum length was about 44 cm. The mean length at the end of the first year was 23.1 cm (s.d. = 13.88); at that of the second, 37.3 cm (s.d. = 12.52); and 41.4 cm (s.d. = 9.92) at the third. Oldest fish were three years old. The growth performance index ø' was 3.28 cm year-1. Mortality increased from 0.16 year-1 between the first and the second cohort, to 0.8 year-1 between the second and third. The results show that black bass in Brazil grows faster than in its area of origin, but longevity is shorter and body shape, stouter. The cause of high mortality at a relatively early age may be connected with the loss of genetic diversity due to inbreeding of the Brazilian stocks, which originated from few introduced individuals a long time ago. The fact that black bass reproduces in reservoirs and grows rapidly may be considered a threat to conserving fish diversity in Brazilian ecosystems.

Change in the rocky reef fish fauna of the iconic Poor Knights Islands Marine Reserve in north-eastern New Zealand over 4 decades

2018 ◽  
Vol 69 (10) ◽  
pp. 1496
Author(s):  
David R. Schiel ◽  
Tony Ayling ◽  
Michael J. Kingsford ◽  
Christopher N. Battershill ◽  
J. Howard Choat ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Species ◽  
Marine Reserve ◽  
Fish Fauna ◽  
Rocky Reef ◽  
Long Term Effects ◽  
Before And After ◽  
Negative Effect ◽  
Reef Fish Species

Marine reserves exhibit increases in targeted fish species, but long-term effects on biodiversity are poorly understood. Factors other than reserve status may affect decadal changes, including environmental change. We examined the fish fauna at the iconic Poor Knights Islands over 4 decades (1974–2016) before and after implementation of a no-take marine reserve in 1998. We document a substantial increase in commercially and recreationally targeted Chrysophrys auratus, which was virtually absent before 1994 but by 2016 had reached up to 11 fish per 500m2 (220 per hectare). There were also large changes to the fish community, including the decline of subtropical and coastal wrasses, some species with no change and others that increased significantly. Many declines occurred >20 years before the arrival of abundant C. auratus, suggesting the changes do not represent a trophic cascade. Furthermore, this normally benthic-feeding fish has adopted a mid-water foraging behaviour targeting planktivorous fish. The increase in C. auratus appears to be linked both to reserve status and catch regulations in the wider region. Overall, the data point to long-term environmental fluctuations from the late 1970s having a negative effect on the abundance of more than half the reef fish species at these islands.

scholarly journals Aquatic insects as the main food resource of fish the community in a Neotropical reservoir

2009 ◽  
Vol 7 (4) ◽  
pp. 701-708 ◽  
Author(s):  
Ana Paula Vidotto-Magnoni ◽  
Edmir Daniel Carvalho
Keyword(s):  
Aquatic Insects ◽  
Food Resource ◽  
Gravimetric Method ◽  
Stomach Contents ◽  
Food Resources ◽  
Food Category ◽  
Main Food ◽  
Tietê River ◽  
Two Samples ◽  
Terrestrial Insects

We evaluated the feeding of fish species of the Nova Avanhandava Reservoir, low Tietê River, São Paulo State, Brazil. Fishes were collected in two stretches of the reservoir: Santa Bárbara (14 samples) and Bonito (two samples) between September 2002 and March 2004, using gill and seining nets. The results of stomach contents analysis were expressed with the frequency of occurrence and gravimetric method, combined in the Alimentary Index (AI). The 20 species studied consumed 52 food items, grouped in 10 food categories: aquatic insects, terrestrial insects, crustaceans, fish, macroinvertebrates, microcrustaceans, algae, vegetal matter, detritus/sediment and scales. The aquatic insects (mainly Chironomidae, Odonata and Ephemeroptera) were the most common food resources, consumed by 18 species. The diet composition of the community (species grouped) indicated that the dominant food category in the diet of fishes was aquatic insects (AI = 77.6%), followed by crustaceans (AI = 7.1%). Four trophic guilds were identified according a cluster analysis (Pearson distance): insectivorous (10 species), omnivorous (4 species), detritivorous (3 species) and piscivorous/carcinophagous (3 species). Despite the highest number of species, the insectivorous guild was responsible for more than 80% in captures in number and biomass (CPUEn and CPUEb). The low values of niche breadth presented by all species, along with the low values of diet overlap between species pairs indicate a high degree of food resources partitioning among species. The aquatic insects, despite being the main food resource of insectivorous fishes, also complemented the diet of other species, which demonstrate the importance of this food resource for the fish community, sustaining a high diversity, abundance and biomass of fishes.

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