Zoology of Aquatic Vertebrates 

Fishes

Studies focusing on the ichthyology of the RLaC Site started at the beginning of the Long-Term Ecological Research Program, in 1999. After nearly 20 years of studies in the region of this Site, with the continuous addition of professional ichthyologists and students to the research team, about one hundred species of fishes are now recorded in the coastal lagoons of the Restinga de Jurubatiba National Park (RJNP) and in the Imboassica Lagoon, which is located in the urban portion of the city of Macaé (Di Dario et al., 2013; Petry et al., 2016).

The ichthyofauna inhabiting those coastal lagoons and their associated pools originates mostly from continental drainages associated with the Paraíba do Sul River Basin and the Feia Lagoon. Both systems are outside the RJNP boundaries, but they are hydrologically connected to the coastal lagoons through the Campos-Macaé artificial channel, and also through flooding events during heavy precipitation periods. An interesting part of the fish composition of the lagoons in the region also originates from the adjacent ocean. Non-native species have also been recorded in the lagoons, consisting of species directly introduced into the lagoons or that apparently dispersed from adjacent basins after introductions outside the lagoons where they are now recorded (Di Dario et al., 2013).

The environmental dynamics imposed on the species of fishes inhabiting lentic ecosystems of the RLaC Site result from phenomena in different timescales (continuous, annual and pluriannual). This is the basis on which the research currently conducted in the Site is justified. The three main phenomena in different timescales associated with RJNP environmental dynamics are:

- percolation of marine water throughout the sandbar located between each lagoon and the adjacent ocean, a condition that results in higher levels of salinity in waters of the lagoons close to the sandbar in relation to the region of the lagoon which is located in the opposite side (continuous event);

- direct intrusion of marine water over the sandbars, a condition that dramatically increases the salinity of small lagoons, generally occurring between May and September (annual event);

- drastic oscillations of rainfall regime due to “La Niña” and “El Niño” events, with decreasing or increasing of precipitation levels, respectively. In the northern portion of the Rio de Janeiro State, rainfall is usually concentrated during the hottest months of the year (between October and March) when those large-scale climatic phenomena are less pronounced (pluriannual event).

Prolonged droughts results in local extinctions of populations of different species of fishes, especially in shallow water lagoons, as is being recorded this year (2017). Long-lasting high precipitation averages, in turn, as recorded between 2007 and 2009, increase the hydrologic connectivity among the Paraíba do Sul River, the Feia Lagoon, and the lagoons of the RJNP and their associated pools. The waterways represented by the channels act as passage for fishes flowing out of important, perennial, regional main water bodies, such as the Paraíba do Sul River, Macabu River and the Feia Lagoon. Freshwater species that are able to disperse through those waterways can reorganize communities of perennial coastal lagoons and start new assemblages in temporary lagoons formed in the flooded coastal plain (Felice, 2014).

Floods and even recurrent intra-annual precipitation averages higher than historical records triggers a phenomenon that results in great changes in fish composition of some RLaC coastal lagoons, which is the sandbar breaching. Those events are caused by an increase in the pressure of the water mass upon the sandbar. When the sandbar breaches, freshwater fishes are carried out to the ocean, where they die, whereas juveniles of marine species with brackish water affinities, such as mullets, mojarras and some species of sole, invade the temporarily open lagoon. Sandbar breaching is a natural and sporadic phenomenon, but in the last years it has been frequently induced by anthropogenic interventions whenever the excess of freshwater in the lagoons pose a threat to the private patrimony of people living in their margins, or when water quality standards for human use are low due mostly to the artificial eutrophication caused by untreated sewage discharge. In the area covered by our studies, the Imboassica is the lagoon that is most frequently impacted by artificial sandbar openings.

Between 2017 and 2020, studies on the fish fauna of the RLaC Site aim to elucidate how the composition of communities is affected by extreme events, such as precipitation deficits expected for the region. We also expect to detect phenotypically plastic species that are able to cope with environmental changes in distinct timescales. Several studies conducted in the Site investigate the correlations among phenotipic plasticity and behavioral, reproductive and acquisition and partitioning of resources (e.g., Araújo et al., 2014; Ventura, 2015; Sommer-Trembo et al., 2017; López-Rodríguez, 2015). Biological invasions in the coastal lagoons are also being studied, aiming to evaluate possible predictors and estimate the vulnerability level of ecosystems. The information on invasive species will be presented as geospatial maps that will help to support the management of the RJNP. In addition, with the inclusion of the Feia Lagoon in the study area, we will be able to identify how much of the fish regional diversity previously identified in the coastal lagoons and temporary pools is also present in this water body, elucidating its possible relevance to the maintenance of the fish communities of the lagoons of the northern Rio de Janeiro State in general. Those actions combined will provide subsidies for the conservation and management of the lagoons and ecosystems of the Restinga de Jurubatiba National Park, an important environmental patrimony of the Rio de Janeiro State.

 

Zoology of Aquatic Vertebrates Team

 

Ana Cristina Petry (petryanacristina@gmail.com)

Lattes: http://lattes.cnpq.br/9840922547339289

 

Erica Pellegrine Caramaschi (erica.caramaschi@gmail.com)

Lattes: http://lattes.cnpq.br/5356106015121653

 

Fábio Di Dario (didario@gmail.com)

Lattes: http://lattes.cnpq.br/2261018203276484

 

Luciano Gomes Fischer (luciano.fischer@gmail.com)

Lattes: http://lattes.cnpq.br/7046655802943775

 

Michael Maia Mincarone (mincarone@gmail.com)

Lattes: http://lattes.cnpq.br/0194631586754988

 

Pedro Hollanda Carvalho (hollandacarvalho@gmail.com)

Lattes: http://lattes.cnpq.br/9551567862449740