Northern Coast Of Brazil Research Articles

Effects of the middle Holocene high sea‐level stand and climate on Amazonian mangroves

ABSTRACTThe high sea‐level stand during the mid‐Holocene is a benchmark in mangrove dynamics along the north‐east/south‐east coast of Brazil and provides a reference point for landward and seaward mangrove migrations corresponding to changes in relative sea level (RSL). However, evidence of the impacts associated with RSL fall on the northern Brazilian coast is scarce. Multi‐proxy data from the highest tidal flats of the Bragança Peninsula in northern Brazil revealed modern herbaceous areas were occupied by mangroves Rhizophora and Avicennia from ~6250 to ~5850 cal a bp, and only Avicennia between ~5850 and ~5000 cal a bp. The same tidal flats were vegetation‐free between ~5000 and ~4300 cal a bp. A combination of a high sea‐level stand (0.6 ± 0.1 m) at ~5000 cal a bp and a dry early–middle Holocene in the Amazon probably caused an increase in porewater salinity of tidal flats, which resulted in a mangrove succession from Rhizophora to Avicennia dominance. RSL fall accentuated this process, contributing to mangrove degradation between ~5000 and ~4300 cal a bp. RSL fall, and a wetter period over the past ~4300 cal a bp caused a mangrove migration from highest to lowest flats, followed by expansion of herbaceous vegetation on the highest flats.

Ectoparasites infecting Mugil curema (Mugiliformes: Mugilidae) in Amapá state estuary, in the northern Brazilian coast region.

In fish, one of the most important interactions is that occur between parasite species and environment. Wild fish interactions with parasites of different taxa can result in diseases for fish and consequently damages to the fishing industry. This study investigated the ectoparasite fauna in Mugil curema (Valenciennes, 1836), in Amapá state estuary, in Brazilian coast region. The parasite prevalence was 51.4%, and a total of 282 parasites were collected among Ligophorus brasiliensis (Abdallah, Azevedo & Luque 2009), Excorallana longicornis (Lemos de Castro, 1960), larvae of Gnathia sp. and Ergasilus atafonensis (Amado & Rocha, 1995), but L. brasiliensis was the dominant parasite. The parasites presented highly aggregated dispersion, except for Gnathia sp. that had a random dispersion. There was a predominance of hosts non-parasitized and parasitized by one species. The relative condition factor did not differ between parasitized and non-parasitized fish. The body size of hosts did not influence the parasite abundance. The community of ectoparasites consisted of low species richness with low infection levels. This is the first study on parasites of fish from the coast of the State of Amapá and is the first report of Gnathia sp. for M. curema.

Near-Surface Atmospheric Turbulence in the Presence of a Squall Line above a Forested and Deforested Region in the Central Amazon

Squall lines (SLs) are convective systems that cause heavy precipitation and consequently modify the atmospheric thermodynamic structure near the surface. SLs generated along the northern coast of Brazil and their effect upon atmospheric structure during their westward displacement into the Amazon are studied. Satellite imagery was employed to identify an SL above two experimental sites in the central Amazon and to characterize differences in the near-surface turbulent and ozone exchange during the passage of the SLs. The two sites, which are separated by about 100 km, feature contrasting vegetation. One site is tall canopy rainforest and the other is deforested. From our case study, it is noted that: equivalent potential temperature significantly drops, principally in the forested region; the average near-surface wind speed increases 5 fold; the skewness of vertical wind velocity becomes considerably negative; significant increases in turbulence intensity are observed. These changes suggest the presence of strong downdrafts generated by the SL. Shear production and dissipation rate of turbulent kinetic energy are considerably larger during the SL when compared to periods with absence of SL. In this study, we show that SLs are capable of modifying the vertical organization of the turbulence over forested and deforested areas, leading to changes in certain chemical processes that occur near the surface. To the best of our knowledge, this study represents a first in demonstrating that near-surface turbulent flow in the Amazon region is modified by the presence of SLs.

An integrative approach using DNA barcode and scanning electron microscopy for the effective identification of sympatric species of the genus Farfantepenaeus Burukovsky, 1997

Farfantepenaeus subtilis, F. isabelae, and F. brasiliensis occur in sympatry along the northern coast of Brazil, up to the state of Rio Grande do Norte. The species of Farfantepenaeus are highly similar and new approaches are needed to better distinguish them. Here, we combined molecular and morphological analysis including scanning electron microscopy for more efficient identification and differentiation of these three species. The molecular analysis confirmed the efficacy of the set of diagnostic characters currently available for the species. The morphological analyses led to the definition of a new dichotomous character between F. subtilis and F. isabelae and uncovered other differences, which furnished new data to the formulation of an updated diagnosis of the target species. Our results contribute to more effective identification of these species, serving as a baseline for the adequacy of fishing management practices throughout their area of occurrence and for future studies on systematics and ecology.

Effects of freshwater limitation on distribution patterns and habitat use of the West Indian manatee, Trichechus manatus, in the northern Brazilian coast

Abstract The West Indian manatee (Trichechus manatus) is a Vulnerable species threatened by habitat loss in the coast of north‐eastern Brazil. This study investigates how the distribution and habitat use of the West Indian manatee is influenced by resource availability in a scenario of freshwater limitation. Land‐based and boat surveys were conducted to record manatee sightings and habitat use, in a total of 206 hours of observation. Manatee abundance was significantly influenced by freshwater availability, with greater abundances occurring close to freshwater sources. Food availability and the variation in freshwater availability between seasons were also important to determine their distribution. For the 47 manatees sighted, 39 were recorded during the rainy season and eight during the dry season. Habitat use was influenced by freshwater sources and manatees spent more time (average coefficient of area use = 24.96%) in areas with greater availability of fresh water. Under conditions of freshwater limitation, manatees were more abundant and spent more time closer to fresh water than to food sources; as a result, animals' distribution varied between seasons. The results found here can help to determine conservation strategies for the region with the highest population density and genetic variability of West Indian manatees in Brazil.

Sobre a carcinofauna acompanhante na pesca industrial do camarão-rosa na plataforma continental Amazônica

Este trabalho foi realizado com objetivo de quantificar a carcinofauna acompanhante por estação do ano, período do dia e faixa de profundidade na pesca industrial do camarão-rosa na Plataforma Continental Amazônica. O estudo foi realizado a partir de 152 registros de operações de pesca ou arrastos de fundo, sendo 72 na época de chuva (dezembro a maio) e 80 na época de seca (junho a novembro), com duração média de 3,5 ± 1,5 horas, totalizando 532 horas de arrasto, nos meses de julho e setembro de 2010 e março e abril de 2011, entre os estados do Pará e Amapá. Inicialmente a fauna acompanhante foi classificada em cinco grupos: peixes, camarão-rosa, crustáceos, moluscos e outros. Em seguida, foi realizada a triagem das comunidades de crustáceos: caranguejos, portunídeos, camarões, lagostas e estomatópodes, onde cada grupo foi quantificado em peso e número de exemplares. Das amostras coletadas no período do estudo, obteve-se uma relação camarão-rosa/fauna acompanhante na época de chuva de 1:3, e na época de seca de 1:30. A carcinofauna diferiu significativamente entre época do ano e entre faixa de profundidade, mas não entre o período do dia. A relação entre o volume (kg) de camarão-rosa capturado e carcinofauna oscilou muito, com o valor médio de 1:1. Nas pescarias industriais de camarão-rosa na costa norte do Brasil a relação camarão/carcinofauna acompanhante é influenciada pela estação do ano e faixa de profundidade, sendo menos danosa a essa biodiversidade no primeiro semestre de cada ano.

Zooplankton at the Northern Brazilian Coast: Evaluation and Gaps

Leite, A.A.C.; Queiroz, A.F.S.; Morais, L.M.S.; Azevedo, C.C., and Martinelli Filho, J.E., 2020. Zooplankton at the Northern Brazilian Coast: Evaluation and gaps. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 12–17. Coconut Creek (Florida), ISSN 0749-0208.Research on planktonic communities in the Brazilian Northern coast started since the XIX century by foreigners, most of it being taxonomical surveys. The only literature reviews for the area are a technical report and a book chapter published in Portuguese by 2005. This article aimed to analyze the existing literature about zooplanktonic communities at the Northern coast of Brazil from a decade after the last review (2005 to 2015), to update and elucidate possible knowledge patterns and identify existing gaps. The bibliographic review considered the three states of the Brazilian North coast (Maranhão, Pará and Amapá), in the libraries of educational and research institutions, indexing platforms and databases on the internet (Web of Knowledge, Scopus, Scielo and Google Scholar). The most important parameters extracted from the publications were: year and language of publication, zooplankton density, dominant species, sampling mesh size, study area (by state), type of publication, coordinates, and research subject. A total of 222 publications were found, 45 (20.3%) referred to white publications (national and international scientific articles) and 177 (79.7%) referred to gray literature (do not published by peer review system). The Pará state showed a higher number of publications than Amapá and Maranhão sates together. The publications were mostly about zooplanktonic community description, copepod ecology and taxonomy or experimental approaches, and sampling took place mostly on estuarine environments (87.5%). Richness varied from 4 to 68 taxa, while density varied from 0.01 to 962,400 org.m-3. Despite the numerous research in the period, there are important knowledge gaps, mainly in relation to collection sites, target organisms, and research subjects. Future research should focus primarily on oceanic areas (outer shelf) and on themes such as experimental ecology, biogeochemistry and long temporal scale surveys, so that a more comprehensive knowledge about zooplankton on the Brazilian Northern coast can be achieved.

Morphological description of six species of Suberitida (Porifera: Demospongiae) from the unexplored north-eastern coast of Brazil, with emphasis on two new species

AbstractThe Order Suberitida is defined as a group of marine sponges without an obvious cortex, a skeleton devoid of microscleres, and with a deletion of a small loop of 15 base pairs in the secondary structure of the 28S rDNA as a molecular synapomorphy. Suberitida comprises three families and 26 genera distributed worldwide, but mostly in temperate and polar waters. Twenty species were reported along the entire Brazilian coast, and although the north-eastern coast of Brazil seems to harbour a rich sponge fauna, our current knowledge is concentrated along the south-eastern Atlantic coast. A survey was implemented along the northern coast of Brazil, and the collection allowed the identification of six species belonging to the Order Suberitida. Two of them are considered new to science:Suberites purpurasp. nov.,Hymeniacidon upaonassusp. nov., and four,Halichondria(Halichondria)marianaeSantos, Nascimento & Pinheiro, 2018,Halichondria(H.)melanadociade Laubenfels, 1936,Suberites aurantiacus(Duchassaing & Michelotti, 1864), andTerpios fugaxDuchassaing & Michelotti, 1864, are re-described. Taxonomic comparisons are made for Tropical Western Atlantic species and type species of the four genera. Finally, an identification key for the Western AtlanticSuberitesspecies is provided.

Biology, ecology and behavior of the acoupa weakfish Cynoscion acoupa (Lacepède, 1801) according to the local knowledge of fishermen in the northern coast of Brazil

Local ecological knowledge (LEK) of fishers and other actors involved in the fishery can be provide information on the life cycle of fish species they harvest, help defining low-cost sampling projects, new biological hypotheses, management activities and policy measures. This study focuses on fishers’ LEK on diet, feeding, spawning grounds, reproductive size, exploited sizes and perceived changes in abundance over the years of the acoupa weakfish (Cynoscion acoupa), a commercially important marine species. Results from interviews with 240 actors (fishers, captains and boat owners) involved in C. acoupa fisheries in eight municipalities in the northern coast of Brazil indicated that: (a) C. acoupa feeds in areas with rocky bottoms down to the depth of 30 m, eating mainly fish, particularly another weakfish (Macrodon ancylodon) and sardines (Engraulidae); (b) this fish spawns in rocky and non-estuarine habitats; (c) the spawning period mentioned by fishers coincided with the harvest period, but was in disagreement with published scientific information; (d) the median minimum length of individuals of C. acoupa carrying eggs according to interviews was of 70 cm, which was smaller than the length reported in biological studies, possible due to the selectiveness of fishing; (e) there is an overall perception of a decrease in the abundance of C. acoupa among the interviewed fishers, which is compatible with studies on stock exploitation of this species. The current dearth of financial and human resources available for scientific research underlines the importance of making use of LEK to improve fishery policy and management.

Fortnightly variability of total suspended solids and bottom sediments in a macrotidal estuarine complex on the Brazilian northern coast

Macrotidal estuaries are highly dynamic and complex environments that need to be understood in many aspects. In this context, the study of sediments is an important tool in the understanding of the processes in estuarine environments. The aim of the present study was to characterize the temporal and spatial distribution of total suspended solids (TSS) and bottom sediments of the Arraial Bay Estuarine Complex and their dynamics under different tidal conditions during different periods. Nine stations were selected within Arraial Bay Estuarine Complex, in Maranhense Gulf, where water samples were collected at two depths in different periods and tide conditions. The following parameters were analyzed: temperature, salinity, turbidity, total suspended solids (TSS), and bottom sediments for grain size analysis, in addition to cross sections to calculate the estuarine flow rate. Temperature, and pH, was within the expected range for the region, with little spatial or temporal variation. The precipitation and the hydrodynamics caused by tidal movements in the region are important controllers of salinity, estuarine flow, TSS and turbidity, which showed spatial and temporal variations. There is a predominance of fine material, mainly composed of silt, which suggests that mangroves are important in the supply and imprisonment of these sediments within the estuarine complex. In addition, tides play an important role in the distribution of suspended and bottom sediments, and in the dynamics of the resuspended one, controlling TSS concentrations and distributions of bottom sediments along the estuarine complex.

Ontogeny of the skull of Sotalia guianensis (Cetartiodactyla: Delphinidae) on the Northern coast of Brazil

ABSTRACT This study aimed to investigate the ontogenetic development of the skull in the Guiana dolphin (Sotalia guianensis Van Bénéden, 1864 ) through the comparison of 29 morphological non-metrical characters together with the estimated age of 54 specimens derived from four areas on the northern coast of Brazil. The state of each character was associated with the age of each specimen to assess the formation of bone structures, and the degree of fusion of the sutures in each state of the character studied. Nineteen qualitative morphological characters presenting state ontogenetic variations have been analyzed statistically. The analysis depicted that the characters associated with the parietal-frontal suture, parietosupraoccipital, parietoexoccipital, supraoccipital-exoccipital and basioccipital-pterygoid varied according with the age. The results suggest that the physical maturity of the cranium was more premature in the specimens from the Northern Coast, suggesting a geographical adjustment of the species, or a biological response to an intense pressure of by-catch in fisheries over decades on the populations.

The deep sea teleost fish fauna of the Brazilian North Coast

Abstract Data on the deep sea fishes found off the northern Brazilian coast are restricted to the results of the surveys of the RV Oregon, a research vessel of the North American National Marine Fisheries Service, and the REVIZEE Program. The REVIZEE Score-Norte Program focused on commercial fish species and natural resources with potential for exploitation on the continental shelf and slope off the northern coast of Brazil. In this sense, the REVIZEE Score-Norte Program generated little information on species of no commercial value, did not catalog its inventory in zoological collections, and did not publish species lists. Given this considerable knowledge gap on the deep-sea fish found off the North coast of Brazil, we compiled all the available data on the deep-sea fish of this region and also retrieved photographic records from the REVIZEE Score-Norte Program, including the PRODEMERSAL and PROTUNA projects. Considering the published records, specimens deposited in zoological collections, and the interpretation of photographic records, we compiled a list of 63 species of deep-sea fish from the North coast of Brazil. An additional 30 species were found in the published records from the PRODEMERSAL and PROTUNA, but were considered to be doubtful or pending confirmation.

Biometric relationships between body size and otolith size in 15 demersal marine fish species from the northern Brazilian coast

ABSTRACT The relationships between fish size and sagitta otolith measurements were calculated for the first time for 15 species belonging to six families from the northern Brazilian coast. A total of 220 fish were sampled from the bycatch landed by the bottom-trawl industrial shrimp-fishing fleet between August and September 2016. All species had strong relationships between otolith measurements and fish total length with the coefficient of determination (r 2) ranging between 0.71 and 0.99. The variable most strongly related to fish total length was found to be the sagittal otolith length (OL) with 98% of the variability. These relationships are a useful tool to estimate length and mass of preyed fish from otoliths found in stomach contents of marine predators.

The Tonkin weakfish, Cynoscion similis (Sciaenidae, Perciformes), an endemic species of the Amazonas-Orinoco Plume

ABSTRACT Despite its importance in biogeographical, ecological, and commercial terms, the fish fauna of the northern Brazilian coast is still poorly known, representing the least sampled portion of the Brazilian Exclusive Economic Zone. We collected Tonkin weakfish, Cynoscion similis specimens during extensive surveys of the northern Brazilian coast and concluded that C. similis is common in this region. While the species had not previously been reported for the northern Brazilian state of Pará, it may have been recorded in studies of industrial fisheries, being identified only as Cynoscion sp. or by the common name pescada negra. This reinforces the need for the reliable taxonomical identification of species, to guarantee the collection of accurate data on ecology and fisheries, and ultimately, support the development of effective conservation strategies. Here we provide additional morphological and molecular data to distinguish Cynoscion similis from the closely related Cynoscion jamaicensis, and other congeners.

Squall‐line initiation over the northern coast of Brazil in March: Observational features

AbstractThe daily cycle of atmospheric conditions related to squall‐line (SL) initiation over the northern coast of Brazil (NCB) was obtained for a specific month (March) over the course of a decade (2004–2013). March falls during the NCB's rainy season. A comparison of atmospheric conditions between two categories, the most intense SL events (SLC+) and the weakest coastal convection events (CC–), was carried out. For both categories, the daily cycle of convective cluster properties (i.e. number and area) over the NCB showed that the transition from shallow to deep convection occurred from 1200 to 1500 UTC, and the development of multicell storms occurred from 1500 to 1800 UTC. From 1800 to 2100 UTC for the SLC+ events, the number of clusters decreased sharply, and the area slightly expanded, which indicated upscaling via merging; for the CC– events, merging was a secondary mechanism, and the clusters did not experience upscaling. Atmospheric conditions were computed from the ERA‐Interim reanalysis data. By focusing on the significant differences between the categories, it was found that SL initiation was related to a higher moisture content at approximately 700 hPa for all analysis times (0600, 1200, 1800 and 0000 UTC) and to a stronger low‐level moisture convergence from 0600 to 1800 UTC, mid‐level upward motion from 1200 to 0000 UTC, low‐level convergence at 1200 UTC, and upper‐level divergence from 1800 to 0000 UTC.

Widespread microplastics distribution at an Amazon macrotidal sandy beach

Microplastics (MPs) are widespread and cause many impacts, yet their distribution and abundance are unknown for the Amazon coast. We estimated the abundance and distribution of microplastics at a sandy beach on the northern Brazilian coast during April 2014. Sand was collected and analyzed at three depth strata (0–20, 20–40 and 40–60 cm). MPs (250–500, 501–5000 μm) from each depth were sieved and retrieved by flotation when necessary. We found 492.5 ± 556.4 particles m−3, with fibers comprising up to 95%. The abundance decreased with depth (61.5, 25 and 13.5% from the surface to 40–60 cm) and the deposition zone showed higher densities compared to the erosion zone. Although present in low to moderate abundance, MPs were widespread on the beach. The Amazon coast is an important area for fisheries and traditional communities, and further studies of its potential as a source or sink of MPs are needed.

Record of the rare Caribbean mud eel, Pythonichthys sanguineus (Heterenchelyidae, Anguilliformes), in the region of the Amazon Reef

ABSTRACT As they spend most of their time buried in the substrate and are not a fishery resource, heterenchelyids are seldom seen. These eels are characterized by their greatly reduced eyes, which are covered by semi-transparent skin, the absence of a pectoral fin or lateral line, and no pores on the head or body. Pythonichthys sanguineus is a particularly poorly-known species, with only eight scientific records from Cuba, Puerto Rico, Colombia, Venezuela, Guyana, and Suriname. The present study is based on six adult specimens of P. sanguineus captured by vessels of the shrimp trawling fleet along the northern Brazilian coast, in the vicinity of the Amazon Reef. We provide meristic, morphometric and DNA barcoding data. These findings provide insights into the distribution of the species off the northern Brazilian coast and contribute to the discussion about the southern limit of the Greater Caribbean fauna.

A review of the records of Pachycheles rugimanus A. Milne-Edwards, 1880 (Crustacea: Decapoda: Anomura: Porcellanidae) from Brazil, with the description of a new species.

All previous records of Pachycheles rugimanus A. Milne-Edwards, 1880, from the Brazilian coast are reviewed and prove to represent a new species, P. coelhoi sp. nov. (from Amapá, northern Brazilian coast), and P. ackleianus A. Milne-Edwards, 1880, a species already known from Brazil (from Pará to Rio de Janeiro). The new species is described and illustrated, and compared to its most similar congeners: P. rugimanus and P. ackleianus from the western Atlantic, and P. velerae Haig, 1960, from the eastern Pacific (Galapagos Island and Cocos Island). Pachycheles coelhoi sp. nov. is distinguishable from the other three species by a suite of morphological characters, which include the ornamentation of the carapace and chelipeds, and the shape of the third thoracic sternite. All previous records of P. rugimanus from Brazil are considered invalid.

Marine Reservoir Corrections for the Brazilian Northern Coast Using Modern Corals

ABSTRACTThe Abrolhos bank, in southern Bahia State (BA), is the largest coral reef system in the southwestern Atlantic. It is highly influenced by the Brazil Current (BC), since it is located in the continental shelf. By contrast, Todos os Santos Bay (TSB), in Salvador, capital of Bahia State (BA) has an important coral biodiversity, located in a bay inlet with restricted water circulation. Coral cores were collected in those sites and were analyzed for density band counting and by Th/U dating to estimate growth rates and age. In this work, we present14C ages of some of these bands in order to evaluate the marine reservoir effect (MRE) to which the colonies were subjected during growth. It is the first study making use of coral skeleton samples for MRE determination for the Brazilian coast. ΔR was calculated to be –151±2314C yr, while that for the TSB was –107±5114C yr.

Range distribution and contributions to taxonomy of Elops smithi (ELOPIFORMES: ELOPIDAE).

This study presents the first record of Elops smithi for northern Brazil. The evidence suggests this species is being misidentified incorrectly as Elops saurus in estuaries of the Western Atlantic Ocean. Here, morphological, molecular, and cytogenetic evidence identified all ladyfish specimens from one estuary in the region as E. smithi. Thus, at least Elops smithi occurs in the northern coast of Brazil and it is recommended that specimens from this region identified as E. saurus be further investigated with genetic and cytogenetic tools in order to assure a correct species identification.