The aggressive behavior of Nile tilapia introduced into novel environments with variation in enrichment

Many studies show environmental enrichment is correlated with benefits to captive animals; however, one should not always assume this positive relationship given that enrichment increases the amount of resources that a territorial animal must defend and possibly affects its aggressive dynamics. In this study, we tested if environmental enrichment affects aggressive interactions in the aggressive fish Nile tilapia (Oreochromis niloticus). We compared fights staged between pairs of male tilapia of similar size (= matched in resource holding potential) in a novel arena that was either barren or enriched, to examine whether enrichment enhances territory value in line with theoretical predictions, with the potential for compromised welfare. We evaluated time elapsed until the first attack (latency), frequency of aggressive interactions and fight duration. We detected fight dynamic differences at the pair level. Higher resource value generated increased aggression but had no effect on fight duration or latency. This conclusion is in line with game theory predictions concerning resource value and contradicts the theory that enrichment of the environment will serve welfare purposes. (C) 2010 Elsevier GmbH. All rights reserved.

Influence of artificial reefs on fish assemblage of the Barra Bonita Reservoir (São Paulo, Brazil)

This paper deals with the effects of introduced artificial reefs on the diversity of freshwater fish communities in lentic and lotic zones of a very impacted river in southeastern Brazil. To accomplish this goal, artificial reefs were introduced, in December 1997, in the Barra Bonita reservoir and in the lotic zone immediately below the dam. Fish diversity was always higher in the lotic zone than in the reservoir. Accordingly, fish diversity near the artificial reefs was consistently higher than in the control areas. We propose that the higher environmental complexity in the lotic zone, as compared to the reservoir, is incremented in areas where artificial reefs were introduced; also, we present that, in both areas, diversity is mainly affected by the introduction of artificial reefs.

Structural enrichment reduces aggression in Tilapia rendalli

Environmental enrichment seeks to improve the behavior of captive animals. Few studies have developed enrichment strategies for fish, particularly for use in aquaculture. Environmental enrichment for territorial and aggressive animals has the potential to increase both the amount of defensible resources and the value of a disputed territory which can increase the level of aggression. This study evaluated this hypothesis for the redbreast tilapia, Tilapia rendaIli. We used a short-term approach for evaluation of fish aggressive behavior by recording it for 30 min after introduction of a pair of fish into each experimental aquarium. Our main finding was that the latency to start a fight was lower in an enriched environment, but the frequency of attacks was higher in a non-enriched environment (control). Furthermore, we observed clear hierarchical behavior (submissive dark stripes on the body and dominant light-colored bodies without stripes) only in the non-enriched environment. Structural enrichment of the environment for redbreast tilapia leads to decreased aggression and cohabitation without hierarchical dominance. © 2013 Copyright Taylor and Francis Group, LLC.

Análise geoambiental da baixada santista da Ponta de Itaipu ao Maciço de Itatins (SP)

Pós-graduação em Geociências e Meio Ambiente - IGCE

Validação de bioindicadores de recuperação de áreas degradadas por minerações de bauxita em Poços de Caldas, MG

Pós-graduação em Geociências e Meio Ambiente - IGCE

Preferência alimentar por insetos aquáticos em espécies de peixes de riacho tropical

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da dinâmica climática e sua influência na qualidade da água de reservatórios urbanos

The present study sought to develop a methodology to analyze the water quality based on concepts and methods of climate and climatology respectively. In this way, it was tried to relate techniques and methodologies hydro and limno-meteorological with a rhythmic analysis technique developed within the Brazilian geographical climatology to assess and analyze the blooms of cyanobacteria, the main index of water quality found in reservoirs of “Alto Tietê” Basin and consequently the Metropolitan Region of São Paulo, an area of high environmental complexity due to its high degree of development and high population density. The meteorological data used to develop the study were collected from the meteorological station of the IAG / USP and the limnological data were collected from the Hydrological Monitoring System implemented by SABESP in Billings and Guarapiranga reservoirs as well as data laboratory of the same entity. The results obtained by the rhythmic and integrated analyze showed that the process of blooms of cyanobacteria is dependent not only on one specific factor, but a combination of meteorological factors that may disrupt the stability of reservoir and which can, during the stabilization process, provides the necessary conditions to the development of cyanobacteria. It was also shown by the results that the pace of Atlantic Polar Front Entrance during the winter in São Paulo, is a limiting factor to the growth of cyanobacteria due to their high frequency, keeping the reservoir balance throughout the period. Furthermore, another importance of this study is the possibility of prevention and forecasting periods which are inappropriate for the use of these reservoirs mainly for recreational activities

The climatic rhythm and blooms of cyanobacteria in a tropical reservoir in São Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complexidade do ambiente e assimetria no andar de idosos com doença de Parkinson

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estrutura da comunidade parasitária de duas espécies de peixes autóctones da RPPN Foz do rio Aguapeí, Alto rio Paraná

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Environmental enrichment reduces aggression of pearl cichlid, Geophagus brasiliensis, during resident-intruder interactions

Em lutas entre peixes residentes e intrusos, residentes geralmente vencem, provavelmente porque valorizam o território mais do que os intrusos. Nós aventamos a hipótese de que ambientes enriquecidos aumentam o valor da área em disputa, levando os residentes a defenderem mais violentamente ambientes enriquecidos de recursos do que ambientes empobrecidos, pois possuiriam mais motivação para mantê-lo. No entanto, no presente estudo, ao testarmos as interações entre intrusos e residentes em acarás, Geophagus brasiliensis, observamos que o enriquecimento ambiental reduz a agressividade e pode levar a cohabitação entre os peixes, sem luta. Adicionalmente, em nossos experimentos, o efeito da residência prévia ocorreu independente da condição de enriquecimento. A diminuição das interações entre os peixes e, consequentemente, a diminuição do nível de agressividade é aqui atribuída aos efeitos da diminuição da visibilidade entre os peixes devido ao aumento de complexidade do ambiente.

Dependence of anuran diversity on environmental descriptors in farmland ponds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Logistic regression to estimate the welfare of broiler breeders in relation to environmental and behavioral variables

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The reliability of experts' opinions in constructing a composite environmental index: The case of ESI 2005

The complexity of the environment demands a well-constructed composite environmental index (CEI) to provide a useful tool to draw attention to environmental conditions and trends for policy purposes. Among the common difficulties in constructing a proper CEI are uncertainties due to the selection of the most representative underlying variables or indicators. A degree of uncertainty accompanies experts' judgments, and to deal with vague, subjective or inconsistent information, logic other than classic is required. This study analyzes a procedure that uses different experts' opinions in constructing a CEI. with the use of paraconsistent annotated logic. For this, a sensitivity analysis of the Environmental Sustainability Index (ESI 2005) was used as an example to assess the reliability of experts' opinions. The uncertainty due to the disagreement in experts' opinions clearly indicates that the forms we presently use to measure and monitor the actual environment are insufficient, that is, there is a lack of a "science of sustainability". (C) 2009 Elsevier Ltd. All rights reserved.

A bi-objective genetic approach for the selection of sugarcane varieties to comply with environmental and economic requirements

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)