RESUMO

Alterations in mollusc shells have been proposed contamination biomarkers. We used geometric morphometrics analyses associated with analytical determinations of contaminants to select suitable biological models among species widely distributed on coastal zones. The study was carried out using Lottia subrugosa (herbivore limpet), Crassostrea brasiliana (filter-feeder bivalve), and Stramonita brasiliensis (carnivore gastropod) obtained along a marked contamination gradient at Santos Estuarine System (Brazil). L. subrugosa and S. brasiliensis presented distinct shapes along the gradient, while no significant differences in shell form were seen for C. brasiliana. Indeed, limpets and snails presented morphometric parameters consistent with measured contamination levels hazardous substances. Based on cross-validation models, the reliability of morphometric responses was over 75% for the herbivore and carnivore species. In addition, for S. brasiliensis, a 95.2% confidence was detected in most contaminated sites. Therefore, shell alterations on carnivorous gastropods should be further investigated, seeking to be effectively employed as pollution biomarkers.

Assuntos

RESUMO

Aquatic organisms that inhabit coastal areas are often exposed to several contaminants. It is known that the bioaccumulation of contaminants can be amplified according to the species feeding habits and contaminant properties. As a consequence, species can experience different effects to contaminant exposure even if they inhabit the same area. The present study aimed to investigate the activities of carbonic anhydrase (CA), Ca2+-ATPase, and Mg2+-ATPase in different tissues (soft tissue, mantle, and gill) of three mollusk species (Lottia subrugosa, Stramonita brasiliensis, and Crassostrea brasiliana) with different feeding habits (herbivore, carnivore, and filter-feeder, respectively) which were sampled within a known contamination gradient at Santos Estuarine System (Southeastern Brazil). From the three enzymes tested, only CA was affected by the presence of contaminants within the contamination gradient evaluated. In general, the CA activity from the three species were lower in contaminated sites when compared to the reference site. The contrasting CA activity response observed in S. brasiliensis compared to L. subrugosa and C. brasiliana could be related to the tissue-specificity of this enzyme activity and species feeding habits (filter-feeders can accumulate more contaminants than herbivores and even carnivores). Results indicated that C. brasiliana mantle is the most suitable tissue for the use of CA analysis as a biomarker.

Assuntos

RESUMO

Studies have shown that shell morphology and enzymatic activities in mollusks are affected by contaminants exposure. However, the correlation between enzymatic activities and the biomineralization process are not fully understood. The present study used a transplant bioassay and field sampling to evaluate shell measurements and the activities of carbonic anhydrase, Ca2+-ATPase, and Mg2+-ATPase in Lottia subrugosa sampled in Brazilian sites under different contamination levels. Results showed that, in general, shells from the reference site (Palmas) were more rounded than the ones from the contaminated site (Balsa). Effects in enzymatic activities in specimens from transplant bioassay were attributed to the known high contaminant levels present at Balsa. While the lack of enzymatic activity alterations during field sampling was attributed to physiological adaptation to contaminants exposure. Enzymatic activities were not correlated to shell biometric parameters in field sampling, indicating that these enzymes were not related to shell alterations detected in the present study.

Assuntos

RESUMO

Mollusk shells can provide important information regarding environmental parameters. It is known that shell morphology is affected by both natural and anthropogenic factors. However, few studies have investigated alterations in shell morphology over a historical perspective and considering chemical contamination and climate changes. The present study assessed shell form (shape and size) variations of limpet (Lottia subrugosa) shells sampled from 1950 to 1981 (past) in comparison with organisms obtained in 2018 (present). Differences between shells from the past and present (2018) were detected, being shell weight and height the two most important affected parameters. The differences observed were attributed to the possible increase in contamination over the years due to human population growth and to climate change. Additionally, when shells from the past were evaluated according to the decade they were sampled, results indicate that it was necessary an interval of 40 years to shell form be altered within populations.

Assuntos

RESUMO

This paper describes, based on semi-structured interviews (I = October 2003 to January 2004; II = October 2007 to July 2008), the socio-economic profile of the fishermen (casting nets and fishing rod) that fish in the Ponte dos Franceses Bridge and Patos Lagoon, RS, Brazil. The profile of the fishermen is quite similar to each other and composed by men, retirees, and residents of the neighborhoods near the bridge, with ages between 36 and 57 years. In relation to the target species, the caught organisms are chiefly mullets, shrimps and silversides for the casting net fishermen, and kingfish and white-mouth croaker for the rod fishing. Fishermen using rod fishing can be classified as recreational (hobby), and those using casting net as subsistence fishermen. However, because of the large amount of fish caught, there is the possibility of the latter to market part of its fishing product.

O presente trabalho descreve, com base em entrevistas semiestruturadas (I = outubro de 2003 a janeiro de 2004; II = outubro de 2007 a julho de 2008), o perfil socioeconômico dos pescadores de caniço com carretilha e tarrafa que atuam na Ponte dos Franceses, Lagoa dos Patos, Rio Grande, RS. O perfil destes pescadores é bastante semelhante entre si e pode ser caracterizado como sendo formado por indivíduos do sexo masculino, aposentados, residentes em bairros próximos à ponte e com idades entre 36 e 57 anos. Em relação às espécies-alvo, os organismos capturados são basicamente tainha, camarão e peixe-rei, para os pescadores de tarrafa, e papa-terra e corvina, para os de caniço. Os pescadores de caniço com carretilha podem ser classificados como amadores (passa-tempo), e os pescadores de tarrafa, como de subsistência. Contudo, devido à grande quantidade de pescado capturada, existe a possibilidade de estes últimos comercializarem parte do produto de sua pesca.

RESUMO

This paper describes, based on semi-structured interviews (I = October 2003 to January 2004; II = October 2007 to July 2008), the socio-economic profile of the fishermen (casting nets and fishing rod) that fish in the Ponte dos Franceses Bridge and Patos Lagoon, RS, Brazil. The profile of the fishermen is quite similar to each other and composed by men, retirees, and residents of the neighborhoods near the bridge, with ages between 36 and 57 years. In relation to the target species, the caught organisms are chiefly mullets, shrimps and silversides for the casting net fishermen, and kingfish and white-mouth croaker for the rod fishing. Fishermen using rod fishing can be classified as recreational (hobby), and those using casting net as subsistence fishermen. However, because of the large amount of fish caught, there is the possibility of the latter to market part of its fishing product.

O presente trabalho descreve, com base em entrevistas semiestruturadas (I = outubro de 2003 a janeiro de 2004; II = outubro de 2007 a julho de 2008), o perfil socioeconômico dos pescadores de caniço com carretilha e tarrafa que atuam na Ponte dos Franceses, Lagoa dos Patos, Rio Grande, RS. O perfil destes pescadores é bastante semelhante entre si e pode ser caracterizado como sendo formado por indivíduos do sexo masculino, aposentados, residentes em bairros próximos à ponte e com idades entre 36 e 57 anos. Em relação às espécies-alvo, os organismos capturados são basicamente tainha, camarão e peixe-rei, para os pescadores de tarrafa, e papa-terra e corvina, para os de caniço. Os pescadores de caniço com carretilha podem ser classificados como amadores (passa-tempo), e os pescadores de tarrafa, como de subsistência. Contudo, devido à grande quantidade de pescado capturada, existe a possibilidade de estes últimos comercializarem parte do produto de sua pesca.