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The sampling of fish from the artisanal fleet operating with surface lines off north‐eastern Brazil was carried out between 1998 and 2000. Generalized linear models (GLMs) were used to standardize mean abundance indices using catch and... more
The sampling of fish from the artisanal fleet operating with surface lines off north‐eastern Brazil was carried out between 1998 and 2000. Generalized linear models (GLMs) were used to standardize mean abundance indices using catch and fishing effort data on dolphinfish Coryphaena hippurus and to identify abundance trends in time and space, using 1215 surface line deployments. A standard relative abundance index (catch per unit effort, CPUE) was estimated for the most frequent vessels used in the sets, employing factors and coefficients generated in the GLMs. According to the models, C. hippurus catches are affected by the operating characteristics and power of different fishing vessels. These differences highlight the need for standardization of catch and effort data for artisanal fisheries. The highest mean abundance values for C. hippurus were off the state of Rio Grande do Norte, with an increasing tendency in areas with greater depths and more distant from the coast, reaching m...
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Census of fishing data about the landings carried out along the São Paulo coast during 2011 was used to evaluate and compare the survey sampling for fisheries monitoring, expecting reliable results along with an important cost reduction.... more
Census of fishing data about the landings carried out along the São Paulo coast during 2011 was used to evaluate and compare the survey sampling for fisheries monitoring, expecting reliable results along with an important cost reduction. Estimates of total catch for the São Paulo State as a whole and by municipality were relatively accurate (high precision and low bias). Estimated catch by month, by fish categories and both (factors not considered in the sampling design) demonstrated that, as the level of required detail increased, the catch estimates became more biased and less precise. However, when comparing to the 2011 true catches, the order of importance of fish categories based on estimated catches changed slightly in some positions after the fifth place. There was a minor cost reduction due to the sampling in comparison with the census methodology currently in use (15.4% at most). The results demonstrated that fisheries monitoring costs are directly proportional to the requi...
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As top predators in marine environments, seabirds frequently respond to the presence of their main prey, and both predators and prey are usually associated with specific environmental features. We investigated the variability in the... more
As top predators in marine environments, seabirds frequently respond to the presence of their main prey, and both predators and prey are usually associated with specific environmental features. We investigated the variability in the presence and density of flying seabirds (mostly Procellariiformes and Charadriiformes) and Magellanic penguinsSpheniscus magellanicusalong the southwestern (SW) Atlantic continental shelf. Five acoustic assessment surveys were conducted to determine the biomass of the Argentine anchovyEngraulis anchoita, and seabird counts and the collection of oceanographic data were conducted simultaneously with the surveys between June and October 2010. Generalized linear mixed models (GLMMs) were fitted to test the effect of anchovy density and environmental variables on seabird density. Sea surface temperature was significant for the presence of flying seabirds. Bottom water temperature and anchovy density were key variables affecting the presence and density of penguins, while bottom water salinity was also important for penguin presence. Based on Akaike’s information criterion, the most important factor explaining the density of flying seabirds was the difference between surface and bottom salinity (ΔS), while for penguin density, the most important factor was anchovy density. These results highlight that the subtropical shelf front in the SW Atlantic Ocean is a key feature influencing the aggregation of flying seabirds and confirm the close association of penguins and anchovies. Bottom water intrusion, originating from the sub-Antarctic shelf water, is an important factor explaining the presence of penguins, which tend to aggregate in areas with high anchovy densities on the SW Atlantic continental shelf.
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Bottom trawling, a method of fishing in which nets are dragged across the ocean floor, leads to the death of an estimated 4.2 million tons per year of non-target species worldwide (1), decreases revenue by disrupting the growth of... more
Bottom trawling, a method of fishing in which nets are dragged across the ocean floor, leads to the death of an estimated 4.2 million tons per year of non-target species worldwide (1), decreases revenue by disrupting the growth of juvenile fishes (2, 3), threatens ocean ecosystems worldwide (4), and increases aqueous CO 2 emissions by disturbing the seafloor (5). The coastal shallow waters of the Rio Grande do Sul state in southern Brazil, an ecological hotspot for megafauna and fish feeding, spawning, and nursing, have deteriorated due to extensive fishing. To protect and reconstruct their former fishery productivity, scientific evidence should be valued over the industry’s immediate interests, and bottom trawling should not be allowed in this ecosystem. Extreme overfishing (6, 7) and the chronic inefficiency of federal fisheries management pushed local fishers in Rio Grande do Sul to lead the push for the 2018 approval of the Sustainable Fisheries State Policy Act (Rio Grande do Sul State Law 15,223/2018), which banned all motor-powered bottom trawling up to 12 miles from the state’s 570 km of marine coast. Decades of scientific evidence indicated that the ban would have sustainable Edited by Jennifer Sills ecosystem benefits and ensure continued revenues for small-scale and industrial fisheries (6–8). For the same reasons, trawling bans have been established in other countries (9). However, the law was questioned in Brazil’s Federal Supreme Court in 2019 after the neighboring state Santa Catarina’s industrial fishing sector claimed economic losses. The dean minister maintained the law (10), but in December 2020, his successor suspended it (11). Efficient and effective fisheries management is essential to the food security of the more than one million people along the 8000-km Brazilian coastline for whom fishing is a way of life and primary source of income (12). The new minister’s decision led to uncertainty about the state’s right to legislate on this issue, which could be an enormous setback in ecological and fisheries restoration. We urge the Supreme Court to formally recognize rights of states in Brazil to legislate in their coastal waters. Only then will local and other coastal fisheries be able to choose a sustainable path forward. Luís Gustavo Cardoso*, Manuel Haimovici, Patrízia Raggi Abdallah, Eduardo Resende Secchi, Paul Gerhard Kinas Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, RS, Brazil. Instituto de Economia, Universidade Federal do Rio Grande, Rio Grande, RS, Brazil. Instituto de Matemática, Estatística e Física, Universidade Federal do Rio Grande, Rio Grande, RS, Brazil. *Corresponding author. Email: cardosolg15@gmail.com REFERENCES AND NOTES
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Four distinct Franciscana Management Areas (FMAs) have been proposed based on several lines of evidence including genotype, phenotype, population response and distribution. To determine if differences in external morphology fit this... more
Four distinct Franciscana Management Areas (FMAs) have been proposed based on several lines of evidence including genotype, phenotype, population response and distribution. To determine if differences in external morphology fit this division, a canonical variate analysis was carried out for males and/or females from FMAs I to IV using up to 14 characters. A total of 78 adult specimens were analysed. More than 90% of the differences between groups were summarized by three canonical variates. Females were larger than males in all areas. Females from FMA IV were of intermediate length between those from FMA I and FMA III and individuals from FMA II were smaller than those from all other areas. Position of dorsal fin and morphology of the anterior body region, differentiate individuals from FMA I and FMA III. Morphological differences found in this study give additional support for the proposed FMAs. Since habitat characteristics and franciscana feeding ecology vary regionally, it is possible that observed morphological differences are due to ecological divergence for niche occupation. The indication of a discontinuous distribution, consistency between genetic and morphological evidence, and a short time genetic divergence, might indicate that franciscanas inhabiting FMA I represent a distinct subspecies.
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Abundance estimates are presented for the humpback whales wintering off Brazil which ‘visit’ a surveyed area off Abrolhos Bank and display fluke-exposing behaviour. The study is based on photo-identification data collected between 1996... more
Abundance estimates are presented for the humpback whales wintering off Brazil which ‘visit’ a surveyed area off Abrolhos Bank and display fluke-exposing behaviour. The study is based on photo-identification data collected between 1996 and 2000. Chapman-corrected Petersen estimates for all pairs of data result in estimates from 1,948 individuals up to 3,001 with coefficients of variation around 0.25. A more elaborate closed population multiple-recapture maximum-likelihood estimate is 2,393 with 95% profile-likelihood confidence interval (CI=1,924, 3,060). Replacing the closed-population assumption with a population allowed to grow (or decrease) according to some constant rate over the study period, the maximum-likelihood estimate of population size for the year 2000 becomes 3,871 (CI=2,795, 5,542) associated to an estimated annual growth rate of 31% over the study period and in the surveyed area. Although the inclusion of the growth rate results in a less restrictive assumption abou...
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A anestesia geral de pequenos animais para cirurgia experimental e uma das dificuldades encontradas pelos pesquisadores. Este trabalho tem o objetivo de demonstrar aqueles que utilizam coelhos em cirurgia experimental e nao estao... more
A anestesia geral de pequenos animais para cirurgia experimental e uma das dificuldades encontradas pelos pesquisadores. Este trabalho tem o objetivo de demonstrar aqueles que utilizam coelhos em cirurgia experimental e nao estao habituados com tecnicas anestesicas, ou nao possuem aparelhos de anestesia apropriados, um modelo de anestesia e analgesia intramuscular, simples e facil de executar, mas com a seguranca necessaria para a realizacao dos procedimentos operatorios e com duracao media suficiente, mostrando-se altamente eficaz.
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Spatial and temporal distribution of the yellowtail snapper Ocyurus chrysurus (Bloch, 1791) (Teleostei, Lutjanidae) caught by the artisanal fleet in northeastern Brazil. Fish sampling activities were carried out between 1998 and 2000,... more
Spatial and temporal distribution of the yellowtail snapper Ocyurus chrysurus (Bloch, 1791) (Teleostei, Lutjanidae) caught by the artisanal fleet in northeastern Brazil. Fish sampling activities were carried out between 1998 and 2000, accompanying the landings of bottom-line operations of the artisanal fleet in northeastern Brazil. In order to standardize mean abundance indexes based on catch and effort data regarding Ocyurus chrysurus and identify mean abundance tendencies in time and space, generalized linear models (GLMs) were used on 1556 fisheries recorded during the study period. A standard relative abundance index (CPUE) for the most frequent vessel in catches was estimated, using factors and coefficients generated in the GLMs. Mean abundance indexes indicate that the species has a greater yield in the state of Bahia, with a tendency toward lower values at lower latitudes in the study area. The highest mean CPUE values were estimated between depths of 25 and 50 m. Non-linear ...
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Franciscana dolphin Pontoporia blainvillei bycatch has been high for near six decades in western South Atlantic, with large regional variation. In 2012, the Brazilian Government‐regulated gillnet fisheries in south and southeast Brazil by... more
Franciscana dolphin Pontoporia blainvillei bycatch has been high for near six decades in western South Atlantic, with large regional variation. In 2012, the Brazilian Government‐regulated gillnet fisheries in south and southeast Brazil by reducing fishing effort and establishing no‐fishing zones. However, there is evidence that the magnitude of franciscana bycatch remains high and unsustainable. The aims of this study were to identify hotspot areas of franciscana bycatch associated with two main gillnet fisheries and to propose no‐fishing zones combined with limited total allowable fishing effort (i.e. total net length per season) in order to meet management objectives in southern Brazil. A hierarchical Bayesian model using integrated nested Laplace approximation (INLA) was employed based on 1427 reported settings from 1999 to 2003 and 2006 to 2009. Hotspot zones were detected and are proposed as no‐fishing zone during the white croaker Micropogonias furnieri and striped weakfish Cy...
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At the breeding grounds of most baleen whales the patchiness and gaps in spatial distribution results from interactions between behavior patterns and environmental conditions. We evaluated the influence of environmental factors... more
At the breeding grounds of most baleen whales the patchiness and gaps in spatial distribution results from interactions between behavior patterns and environmental conditions. We evaluated the influence of environmental factors (bathymetry and distance from shore with quadratic terms, and wind speed), effort, and spatial autocorrelation effects to predict humpback whale group density in the Southwest Atlantic Ocean. Count data of groups by grid cells were fitted with conditional autoregressive models (CAR). Bayesian inference was performed via integrated nested Laplace approximation. The best‐fit model contained distance from shore and its quadratic term, bathymetry, and the autoregressive component. Occupancy probability was high for the Abrolhos Bank, some cells from the northeast continental shelf and southeast margin, but gaps in occurrence were identified. High densities were estimated in the east continental margin, with the highest density in the Abrolhos Bank, in some cells ...
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We estimated the abundance of Antillean manatees (Trichechus manatus manatus) through a large-scale project conducted in 2010 in north-eastern Brazil and evaluated the efficacy of an aerial survey for conservation purposes. Two observers... more
We estimated the abundance of Antillean manatees (Trichechus manatus manatus) through a large-scale project conducted in 2010 in north-eastern Brazil and evaluated the efficacy of an aerial survey for conservation purposes. Two observers conducted the survey via flights that maintained an altitude of 150 m and an air speed of 140 km h−1, covering over 2590.2 km2of the coastline. Strip transects were flown in a zigzag pattern. A total of 67 manatees (on- and off-effort) were recorded in 55 sightings. Historical published records of occurrence were formally incorporated using a Bayesian approach. We estimated the manatee population for north-eastern Brazil in the form of a posterior distribution with a mean of 1104 individuals and a 95% posterior probability interval ranging from 485 to 2221 individuals, which indicates high uncertainty. More large-scale studies in the region are warranted to understand temporal trends, in addition to further studies in hotspot areas, with smaller spa...
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Neste artigo implementa-se o programa capture para inferir o numero total de taxis na cidade do rio grande, brasil, utilizando dados de marcacao e recaptura. A estimacao refere-se a uma populacao fechada para a qual o tamanho populacional... more
Neste artigo implementa-se o programa capture para inferir o numero total de taxis na cidade do rio grande, brasil, utilizando dados de marcacao e recaptura. A estimacao refere-se a uma populacao fechada para a qual o tamanho populacional verdadeiro de 240 taxis e conhecido. As informacoes de marcacao e recaptura foram coletadas ao longo de sete ocasioes amostrais. A analise efetuada em capture seleciona o modelo M como o mais apropriado aos dados. A estimativa de maxima verossimilhana de 225 taxis subestima o valor real. Esta subestimativa esta de acordo com estudos simulados em que o modelo M e selecionado quando o modelo gerador dos dados e M, o qual acreditamos ser o modelo conceitualmente mais adequado no presente caso. No entanto, a subestimativa e suficientemente pequena para que se confunda com o erro amostral, uma vez que o intervalo de 95% de confianca [213, 246] cobre o verdadeiro valor. A metodologia aqui proposta tem baixo custo, sendo de facil implementacao. E uma possivel fonte para dados reais e pode ser um recurso didatico para o estudo de modelos de marcacao e recaptura. Palavras-Chave: programa capture, abundância, modelos de marcacao e recaptura
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Cobia (Rachycentron canadum) is an emerging species in aquaculture worldwide scenario. Currently in Brazil, cobia culture has attracted the interest of research institutions and the private sector. Despite the success of its culture in... more
Cobia (Rachycentron canadum) is an emerging species in aquaculture worldwide scenario. Currently in Brazil, cobia culture has attracted the interest of research institutions and the private sector. Despite the success of its culture in other countries, it is important that be undertaken studies to assess the preliminary technical and economic feasibility of cobia production on Brazilian coast. In order to better understand the cobia´s performance in Brazil, a feed trial of this specie was held at the Jaconema Beach located in the Bay of Ilha Grande (Angra dos Reis, RJ, Brazil). Three diets were tested (1) commercial feed; (2) trash-fish and (3) mix of commercial feed, but this data were analyzed in a different way. Three models were made to better represent the best diet according to specific growth rate, feed conversion and weight gain, using a free software R, with Bugs model fit using OpenBUGS, that 1 chains, each with 25.000 iterations where the first 10.000 were discarded.
ABSTRACT Age and growth estimates of shortfin mako sharks Isurus oxyrinchus from the western South Atlantic Ocean were obtained through the analysis of vertebral sections of 245 specimens (126 females, 116 males and 3 with undetermined... more
ABSTRACT Age and growth estimates of shortfin mako sharks Isurus oxyrinchus from the western South Atlantic Ocean were obtained through the analysis of vertebral sections of 245 specimens (126 females, 116 males and 3 with undetermined sex), ranging in size from 78 to 330 cm fork length (FL), using a flexible growth model (Schnute model) and a Bayesian approach. A significant linear relationship was found between FL and vertebral radius for sexes combined. Marginal increment analyses were inconclusive about periodicity of growth band deposition and an annual periodicity was assumed to make age estimations. Specimens were estimated to be between 0 and 28 years of age. The Schnute model provided a good description of the individual growth for both sexes up to 15 years of age. Shortfin mako growth during the first year of life was 33.9 cm (ICr95% = 19.9-40.8) for females and 30.5 cm (ICr95% = 25.6-35.4) for males. Until approximately 15 years of age, both sexes showed similar growth and reached ~217 cm FL. Sigmoid shaped growth curves obtained for both sexes indicated a change in the growth pattern close to 7 years of age. Inconclusive results about periodicity of growth band deposition in the study area make necessary the application of more robust validation techniques in the future. Meanwhile, a precautionary approach that assumes an annual deposition pattern in the western South Atlantic can be used for the assessment and management of stocks of this species, characterized by low fecundity and late maturity.
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Abstract Concern has increased regarding the stock exploitation status of the mullet, Mugil liza, fishery resource, because industrial catches currently exceed artisanal catches. A growing trend in mullet catches involves the... more
Abstract Concern has increased regarding the stock exploitation status of the mullet, Mugil liza, fishery resource, because industrial catches currently exceed artisanal catches. A growing trend in mullet catches involves the overexploitation of other resources and the commercialization of mullet roes. This study complements existing information about the mullet's life cycle by providing estimates on growth and mortality rates for the stock. The mullet, M. liza, has a relatively low growth rate, κ, at approximately 0.17 year−1, a 10.5 year longevity, and an asymptotic length of 662 mm. Based on age–length structure, mullet caught at sea, in both coastal areas and continental shelves, are significantly larger and older than mullet caught at the Patos Lagoon Estuary by artisanal fishermen. The total mortality rate, Z, was estimated to be approximately 0.77 year−1, and the exploitation rate was higher than 0.5 in 3 different scenarios tested with different natural mortality rates calculated in this work.
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Strandings of several species of marine mammals have been monitored over the years off the south coast of Rio Grande do Sul State, southern Brazil. A long time series of records implies extensive databases on strandings. In the region,... more
Strandings of several species of marine mammals have been monitored over the years off the south coast of Rio Grande do Sul State, southern Brazil. A long time series of records implies extensive databases on strandings. In the region, these databases are maintained by two institutions: (i) Núcleo de Educação e Monitoramento Ambiental (NEMA) [Environmental Education and Monitoring Nucleus] and (ii) Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA) [Ecology and Conservation of Marine Mefagauna Laboratory] at the Federal University of Rio Grande – FURG. In order to make the time series as complete as possible and to make it a reliable source for research related to a particular species and region, the present work proposes a methodology for unifying both databases for franciscana (Pontoporia blainvillei) for the period 2000 - 2020 (NEMA, n = 3,029; FURG, n = 4,629). To build the unified database, specific metrics were outlined for the species and region, in order to...
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Abstract. Bayesian statistical analysis has become an important tool in modern fisheries sciences. We assert that this success is due to the ease in which uncertainty can be explicitly incorporated in inference and decision making. To... more
Abstract. Bayesian statistical analysis has become an important tool in modern fisheries sciences. We assert that this success is due to the ease in which uncertainty can be explicitly incorporated in inference and decision making. To appreciate the profound conceptual change implied by the switch from frequentist to Bayesian views, it is necessary to understand probability as a wider, more powerful concept: quantification of inductive logic. The advantages resulting for fisheries sciences are examined and illustrated with examples. Some alleged weaknesses of the Bayesian approach are questioned. The important ability and still under-explored potential of Bayesian decision analysis to keep facts and values apart, is also highlighted. Key words: Uncertainty, plausible reasoning, posterior probability, decision analysis, Pacific cod. Resumo. Estatística Bayesiana em avaliação e manejo de estoques pesqueiros: uma síntese. A análise estatística Bayesiana tornou-se ferramenta importante ...
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PanamJAS is a non-profit Journal supported by researchers from several scientific institutions. PanamJAS is currently indexed in Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
PanamJAS is a non-profit Journal supported by researchers from several scientific institutions. PanamJAS is currently indexed in
We propose a novel Bayesian hierarchical structure of state-space surplus production models that accommodate multiple catch per unit effort (CPUE) data of various fisheries exploiting the same stock. The advantage of this approach in... more
We propose a novel Bayesian hierarchical structure of state-space surplus production models that accommodate multiple catch per unit effort (CPUE) data of various fisheries exploiting the same stock. The advantage of this approach in data-limited stock assessment is the possibility of borrowing strength among different data sources to estimate reference points useful for management decisions. The model is applied to thirteen years of data from seven fisheries of the lebranche mullet (Mugil liza) southern population, distributed along the southern and southeastern shelf regions of Brazil. The results indicate that this modelling strategy is useful and has room for extensions. There are reasons for concern about the sustainability of the mullet stock, although the wide posterior credibility intervals for key reference points preclude conclusive statistical evidence at this time
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The franciscana dolphin, Pontoporia blainvillei, is endemic to the western South Atlantic Ocean. Its distribution is restricted to waters up to 30 m depth, making it vulnerable to human influence. In southern Brazil the artisanal gillnet... more
The franciscana dolphin, Pontoporia blainvillei, is endemic to the western South Atlantic Ocean. Its distribution is restricted to waters up to 30 m depth, making it vulnerable to human influence. In southern Brazil the artisanal gillnet fisheries have increased since the early 1980s, and entanglement mortality of franciscanas has become a source for concern. Strandings have been documented for about 20 yrs, but the impact of incidental captures has remained unknown. In the 1990s numbers of franciscanas incidentally killed by the artisanal gillnet fleet, population size, and the intrinsic growth rate were estimated. I integrated all available information into a population model in order to quantify the impact of incidental kills. The statistical analysis was conducted within a Bayesian framework to maintain coherence while current biological knowledge was weighted with observational data. My analysis indicated a 99% probability that the population is decreasing. For analysis of futu...