TECHNICAL FISHERY INTERACTIONS IN SOUTHERN BRAZIL

Technical interactions arise through the incidental catch of non-target species (by-catch) in targeted fisheries and by the co-existence of fleets exploiting the same resource. This study revises the fishery, gears and species captured in southern Brazil and also identifies the technical interactions between the fleets and the species involved (through mixed catch and by-catch), especially of the bluefish, Pomatomus saltatrix, and the striped weakfish, Cynoscion guatucupa. Data was taken from published material about the southern Brazilian continental shelf fishery, catch records from coastal landing sites, interviews with skippers and managers and data collected by the IBAMA (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis). The demersal teleosts are the most exploited resources, notably the Sciaenids Micropogonias furnieri, C. guatucupa, Umbrina canosai and Macrodon ancylodon (55% in weight). The higher proportion of by-catch of the targeted P. saltatrix by gill netting is due to Brevoortia pectinata and Parona signata. The targeted C. guatucupa by gill netting is more species-diverse. M. furnieri gill netting is very species-selective as only 4% on average of the total catch is regarded as incidental. Trawlers may catch up to 20 species and there is no specific target species. Purse seine is a species-specific gear as, for most of the targeted species, the by-catch is less than 1% by weight. The size range of the exploited P. saltatrix and C. guatucupa differs amongst gears.   RESUMO Interações técnicas na atividade pesqueira do sul do Brasil Interações técnicas estão relacionadas com a captura incidental de espécies não alvo (fauna acompanhante) em pescarias direcionadas e, pela co-existência de frotas explorando o mesmo recurso. Este estudo revisa a pesca, artes de pesca e espécies capturadas no sul do Brasil e também identifica as interações técnicas entre frotas e espécies (através da captura mista ou fauna acompanhante), especialmente para a anchova, Pomatomus saltatrix, e pescada olhuda, Cynoscion guatucupa. Os dados foram obtidos através de material publicado sobre a pesca da plataforma continetal do sul do Brasil, registros de pesca dos pontos de desembarque da pesca costeira, entrevista com mestres e armadores de barcos e dados coletados pelo IBAMA. Teleósteos demersais são os recursos mais explorados, principalmente os Sciaenídeos Micropogonias furnieri, C. guatucupa, Umbrina canosai e Macrodon ancylodon (55% em peso). A maior proporção da fauna acompanhante da pescaria de rede de emalhe direcionada para o P. saltatrix são das espécies Brevoortia pectinata e Parona signata. A pesca de emalhe direcionada para C. guatucupa é mais diversificada. A pesca de emalhe direcionada para M. furnieri é muito seletiva em termos de número de espécies uma vez que apenas 4% em media da captura total é incidental. Arrasteiros podem capturar até 20 diferentes espécies e não há uma espécie-alvo específica. Rede de cerco é uma arte específica uma vez que, para a maioria das espécies-alvo, a fauna acompanhante é menor que 1% em peso. A faixa de comprimento do P. saltatrix and C. guatucupa explorado difere entre as artes de pesca. Palavras chave: pesca, sul do Brasil, interações técnicas.

Fish bycatch of the laulao catfish Brachyplatystoma vaillantii (Valenciennes, 1840) trawl fishery in the Amazon Estuary

This study aimed to analyse the composition and seasonal variation in the fish bycatch of the Brachyplatystoma vaillantii trawl fishery in the Amazon Estuary in 2009 by monitoring the trips of 48 vessels. The bycatch represented 29% of the catches, totalling 22,228 specimens and 52 taxa, distributed in 22 families (the principal families were Ariidae, Pimelodidae, and Sciaenidae). Brachyplatystoma rousseauxii, Plagioscion squamosissimus, and Sciades herzbergii together contributed 69% of the bycatch and were considered consistent bycatch species. Although a higher proportion of bycatch was captured during the rainy season, the seasonal difference was not significant. A multidimensional scaling (MDS) ordination analysis and an analysis of similarity (ANOSIM) indicated that the species composition of the bycatch was similar across the seasons. However, larger numbers of B. rousseauxii and P. squamosissimus were captured during the rainy season, whereas S. herzbergii predominated during the dry season. The marine migrants and estuarine species guilds showed the greatest richness, whereas freshwater migrants were the most numerous. Among the feeding guilds, the zoobenthivores were the most diverse, whereas the piscivores were the most abundant. The results indicate that fishing pressure primarily affects small- (20-30 cm) and medium-sized (30-50 cm) individuals, although the catch of P. squamosissimus was composed primarily of adults. However, the catches of both B. rousseauxii and B. vaillantii were composed primarily of juveniles.Este estudo objetivou analisar a composição e variação sazonal da ictiofauna acompanhante da pesca de arrasto de Brachyplatystoma vaillantii no estuário amazônico, em 2009, através do monitoramento de viagens de 48 embarcações. A ictiofauna acompanhante representou 29% das capturas, totalizando 22.228 indivíduos e 52 táxons pertencentes a 22 famílias, sendo estas as principais: Ariidae, Pimelodidae e Sciaenidae. Brachyplatystoma rousseauxii, Plagioscion squamosissimus e Sciades herzbergii representaram juntas 69% da captura e foram consideradas constantes. Embora o maior percentual de captura tenha ocorrido no período chuvoso, as diferenças sazonais não foram significativas. Análises de ordenação (MDS) e de similaridade (ANOSIM) mostraram que a composição da captura entre os períodos é semelhante; entretanto, maiores capturas de B. rousseauxii e P. squamosissimus foram observadas no período chuvoso, enquanto S. herzbergii foi dominante no período seco. As guildas migrantes marinhas e espécies estuarinas apresentaram maior riqueza, enquanto as migrantes dulcícolas predominaram em percentual de indivíduos. Considerando as guildas alimentares, as zoobentívoras apresentaram a maior riqueza, enquanto as piscívoras predominaram em abundância relativa. Os resultados indicam que a pressão pesqueira atua sensivelmente sobre os indivíduos de pequeno (20-30 cm) e médio (30-50 cm) porte, embora a captura de P. squamosissimus seja composta predominantemente por adultos. A captura de B. rousseauxii e B. vaillantii, entretanto, foi composta predominantemente por juvenis

APLICAÇÕES DE TÉCNICAS MORFOMÉTRICAS NO ESTUDO DA MORFOMETRIA DE PESCADA BRANCA, PLAGIOSCION SQUAMOSISSIMUS, HECKEL (1940), PERCIFORMES, SCIAENIDAE, DESEMBARCADA NA ILHA DE MOSQUEIRO-PA

Este trabalho teve por objetivo comparar dois métodos de análises de variações morfométricas para identificar dimorfismo, considerando a história de vida e o sexo, para a pescada branca, Plagioscion squamosissimus. Os métodos de estudo morfométrico utilizados foram: análise morfométrica tradicional proposta por Lima (1967) e análise morfométrica geométrica de treliça, proposta por Strauss & Bookstein (1982). As medições foram realizadas em 115 indivíduos, sendo 71 fêmeas e 44 machos. Observou-se que o método de morfometria geométrica foi ligeiramente mais eficiente para esta espécie, pois discriminou as fases maduras dos machos e fêmeas, não identificados no método tradicional. Estes métodos de análise podem ser eficientemente utilizados em trabalhos que visam à verificação de dimorfismo entre gêneros e também, considerando a mesma espécie, nos estudos de determinação de unidades de estoques.   Abstract   APPLICATION OF MORPHOMETRICS TECHNIQUES IN THE STUDY OF THE SOUTH AMERICAN WHITE CROAKER, PLAGIOSCION SQUAMOSISSIMUS, HECKEL(1940) , PERCIFORMES, SCIAENIDAE, LANDED IN MOSQUEIRO-PA   This work aimed to compare two methods of morphometric analysis in order to discriminate life histories and sexes of the South American White Croaker, Plagioscion squamosissimus: the traditional method proposed by Lima (1967) and the geometric truss method by Strauss & Bookstein (1982). This work was based on 115 individuals, 71 females and 44 males. The geometric truss was slightly more efficient for this species as it was able to discriminate mature males from mature female phases, when traditional method was unable to discriminate these individuals. These protocols were found efficient for the identification of sexual dimorphism and also for the stock unit identification.   Key words: South American White Croaker, Morphometry, Sexual Dimorphism

Hábitos alimenticios y aspectos poblacionales del salmonete manchado, Pseudupeneus maculatus (Perciformes: Mullidae) sobre la plataforma continental del noreste de Brasil

This study provides information about the feeding habits, population aspects and spatial distribution of the spot­ted goatfish, Pseudupeneus maculatus, along the coast of the tropical Brazilian continental shelf. Distribution patterns are described using length frequencies and catch rates. Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N), along with stomach contents, were analysed to determine the diet of the spotted goatfish. Multivariate analysis and numerical indicators of the diet, such as numerical frequency, frequency of occurrence and weight percentage, were computed to evaluate the diet composition. The mean trophic position was defined using both stable isotope ratios and stomach content analysis. The length at first maturity for the species was determined as 13.7 cm. A slight pattern in size distribution was observed, with mean size increasing with depth along the shelf. The diet was mainly composed of crustaceans, teleosts and Polychaeta. No clear dietary difference was found between habitat types, water depth or latitude. Both trophic positions estimated by stable isotopes and stomach contents analysis ranged between levels 3 and 4. P. Maculatus was found to be feeding on many rare and infrequent prey items, classifying it as a generalist zoobenthivorous predator, probably due to its efficient search strategy.En este estudio se analizaron los hábitos alimenticios y aspectos biológicos del salmonete manchado (Pseudu­peneus maculatus) frente a la costa brasileña. Para describir los patrones de distribución se analizó la estructura de tallas y las tasas de captura. El nivel trófico y la dieta alimenticia se determinaron mediante análisis isotópicos de carbono (δ13C) y nitrógeno (δ15N), además del contenido estomacal. La composición de la dieta fue determinada con análisis multivariados e indicadores numéricos, como la frecuencia numérica, frecuencia de ocurrencia y el porcentaje del peso. Los resultados indicaron que la talla de primera madurez se encuentra en 13.7 cm. Se observó que la talla media incrementó en relación con el fondo. Por otro lado, la dieta estuvo compuesta por crustáceos, teleósteos y poliquetos, asimismo no se evidenciaron diferencias significativas por tipo de hábitats, profundidad y grado de latitud. Los niveles tróficos estimados oscilaron entre 3 y 4, determinándose que P. Maculatus se alimentó de diversas presas, probablemente debido a su eficiente estrategia de búsqueda, clasificándose como depredador zoobentívoro generalista

Ciclo de vida y dinámica poblacional de la enigmática tanaide Chondrochelia dubia (Tanaidacea: Leptocheliidae) en un lecho de algas tropicales

The present study describes the population dynamics and life history parameters of the enigmatic tanaid Chondrochelia dubia collected in Paiva Beach, tropical coast of Brazil. The region was impacted by a large, unexpected oil spill from August to October 2019. Samples were taken monthly between July 2019 and July 2020 in beds of the red seaweed Jania capillacea. The abundance of individuals was negatively correlated with monthly rainfall, with higher abundances in drier months. There was an unexpected significant drop in abundance in September, possibly caused by contact with the crude oil, but the population recovered fully within two months. The parameters of the von Bertallanfy growth equation, calculated for the first time for the species, were Linf=5.26 mm; k=3.36 year–1; t0=0.0. Compared with other studies, the specimens are very small (2.04 ± 0.95 mm in length), females reach sexual maturity very early (L50=2.3 mm), and natural mortality is high (Z=M=5.77 year–1), indicating an opportunistic life strategy. This study reinforces the bioindication potential of C. dubia and the use of bootstrapped length-based methods to estimate key population parameters in small marine invertebrates.El presente estudio describió la dinámica poblacional y los parámetros del ciclo de vida del enigmático tanaidáceo Chondrochelia dubia recolectado en la playa de Paiva, costa tropical de Brasil. La región se vio afectada por un gran derrame de petróleo inesperado de agosto a octubre de 2019. Se tomaron muestras mensualmente entre julio de 2019 y julio de 2020 en lechos de algas rojas Jania capillacea. La abundancia de individuos se correlacionó negativamente con la precipitación mensual, con mayor abundancia en los meses más secos. Hubo una inesperada caída significativa de la abundancia en septiembre, posiblemente causada por el contacto con el petróleo crudo, sin embargo, la población se recuperó por completo en dos meses. Los parámetros de la ecuación de crecimiento de von Bertallanfy, calculados por primera vez para la especie, fueron: Linf=5.26 mm; k=3.36 año–1; t0=0,0. En comparación con otros estudios, los ejemplares son muy pequeños (2.04 ± 0.95 mm de longitud), las hembras alcanzan la madurez sexual muy temprano (L50=2.3 mm), y la mortalidad natural es relativamente alta (Z=M=5.77 año–1), lo que indica una estrategia de vida oportunista. Este estudio refuerza el potencial de bioindicación de C. dubia y el uso de métodos bootstrap basados en la longitud para estimar parámetros de población clave en pequeños invertebrados marinos

LACK OF GENETIC DIFFERENTIATION IN THE ALTANTIC DISTRIBUTION OF WAHOO

SUMMARY In this study we present the analysis of the stock structure of Wahoo (Acanthocybium solandri) using the mitochondrial control region as genetic marker. We analyzed 276 individuals distributed in four locations int eh east and west Atlantic. Samples were from: Northeast Atlantic (AT-NE/BIL94B) (Canary Islands, Spain), from Southeast Atlantic (AT-SE/BIL97) (Côte d’Ivoire and Gabon) and Southwest Atlantic (AT-SW/BIL96). Four of individuals from Southwest Atlantic (AT-SW/BIL96) were genetically identified as Scomberomorus cavalla. The genetic comparison of the four locations failed to show genetic differences. This result suggests a single genetic pool of the Wahoo in the whole Atlantic. Based on these results, ICCAT should reconsider their management strategies for this species in the area studied. RÉSUMÉ Dans cette étude, nous présentons l’analyse de la structure du stock de thazard-bâtard (Acanthocybium solandri) en utilisant la région de contrôle de l’ADN mitochondrial comme marqueur génétique. Nous avons analysé 276 spécimens répartis dans quatre zones de l’Atlantique Est et Ouest. Les échantillons provenaient de : l’Atlantique Nord-Est (AT-NE/BIL94B) (îles Canaries, Espagne), l’Atlantique Sud-Est (AT-SE/BIL97) (Côte d’Ivoire et Gabon) et l’Atlantique Sud-Ouest (AT-SW/BIL96). Quatre spécimens provenant de l’Atlantique Sud-Ouest (AT-SW/BIL96) ont été génétiquement identifiés comme Scomberomorus cavalla. La comparaison génétique des quatre zones n’a pas révélé de différences génétiques. Ce résultat donne à penser à un patrimoine génétique du thazard-bâtard dans l’ensemble de l’Atlantique. En se fondant sur ces résultats, l’ICCAT devrait revoir ses stratégies de gestion pour cette espèce dans la zone à l’étude. RESUMEN En este estudio presentamos el análisis de la estructura del stock del peto (Acanthocybium solandri) utilizando la región de control mitocondrial como marcador genético. Hemos analizado 276 ejemplares distribuidos en cuatro localizaciones en el Atlántico este y oeste. Las muestras procedían de: Atlántico nororiental (AT-NE/BIL94B) (islas Canarias, España), del Atlántico suroriental (AT-SE/BIL97) (Côte d'Ivoire y Gabón) y del Atlántico sudoccidental (AT-SW/BIL96). Cuatro de los ejemplares del Atlántico sudoccidental (AT-SW/BIL96) fueron genéticamente identificados como Scomberomorus cavalla. La comparación genética de las cuatro localizaciones no mostraba diferencias genéticas. Este resultado sugiere un único acervo genético del peto en todo el Atlántico. Basándose en estos resultados, ICCAT debería reconsiderar la estrategia de ordenación para esta especie en la zona estudiada.Versión del edito

Population genetic of Atlantic bonito in the north east Atlantic and Mediterranean

This study assesses the stock structure of Atlantic bonito (Sarda sarda) using the mitochondrial control region as a genetic marker. About 615 individuals distributed in seven locations were analyzed. Two of the locations were in the Mediterranean Sea (MD/BIL95) (Spain and Tunis), three in the northeast Atlantic (AT-NE/BIL94B) (Portugal, Tunis, Morocco and Mauritania), and one in the southeast Atlantic (AT-SE/BIL97) (Côte d’Ivoire). All these samples were obtained thanks to the participation of all authors in two Small Tuna Research Programs funded by ICCAT. The analysis of the genetic variability of the sequence of mitochondrial control regions depicts a clear heterogeneity among locations. The shared genetic pool that comprises the locations within the Mediterranean (Spain and Tunis), including also a sample from the northeast Atlantic (Portugal), is clearly different from the African locations (Senegal and Côte d’Ivoire). Moreover, these two African locations are also genetically differentiated between them. Morocco and Mauritania locations seems to be located in an intermediate situation between these two groups of locations. These results can be used to infer a management policy by ICCAT on the fisheries of this specie

Deep genetic differentiation in the little tunny from the Mediterranean and east Atlantic.

In this study we present the analysis of the stock structure of Little tunny (Euthynnus alletteratus) using the mitochondrial control region as a genetic marker. More than 500 individuals distributed in six locations were analyzed. Samples were from three main regions: Mediterranean (Tunisia and Spain), and northeast Atlantic (Portugal and Senegal) and southeast Atlantic (Côte d’Ivoire and Gabon). Deep genetic differences were found between these locations. The phylogenetic tree showed a complete reciprocal monophyly association of the individuals in two main regions: Portugal, Spain and Tunisia; and Senegal, Côte d’Ivoire and Gabon. The level of genetic differentiation between these two areas is similar to the differences found between species of the genus Euthynnus. These results suggest a scenario of having two species of Little tunny in its Mediterranean-Atlantic distribution. Further evidence with other non-linked genetic markers along morphological and meristic data is necessary to fully confirm these two putative species. However, based on these results a separate management unit can be considered: i) Northeast Atlantic/Mediterranean (Portugal, Spain and Tunisia), and ii) the northeast/Southeast Atlantic (Senegal, Côte d’Ivoire and Gabon). RÉSUMÉ Dans cette étude, nous présentons l'analyse de la structure du stock de la thonine commune (Euthynnus alletteratus) en utilisant la zone mitochondriale de contrôle comme marqueur génétique. Plus de 500 spécimens répartis sur six sites ont été analysés. Les échantillons provenaient de trois régions principales : Méditerranée (Tunisie et UE-Espagne), Atlantique Nord-Est (Portugal et Sénégal) et Atlantique Sud-Est (Côte d'Ivoire et Gabon). De profondes différences génétiques ont été constatées entre ces endroits. L'arbre phylogénétique affichait une association monophylique réciproque complète des spécimens dans deux régions principales : l’UE-Portugal, l’UE-Espagne et la Tunisie ; et le Sénégal, la Côte d'Ivoire et le Gabon. Le niveau de différenciation génétique entre ces deux régions est similaire aux différences constatées entre les espèces du genre Euthynnus. Ces résultats suggèrent un scénario de présence de deux espèces de thonidés mineurs dans sa distribution méditerranéenne-atlantique. Des preuves supplémentaires avec d'autres marqueurs génétiques non liés ainsi que des données morphologiques et méristiques sont nécessaires pour confirmer pleinement ces deux espèces supposées. Toutefois, sur la base de ces résultats, une unité de gestion distincte peut être envisagée : i) Atlantique Nord-Est/Méditerranée (UE-Portugal, UE-Espagne et Tunisie) et ii) Atlantique Nord-Est/Sud-Est (Sénégal, Côte d'Ivoire et Gabon). RESUMEN En este estudio presentamos el análisis de la estructura del stock de la bacoreta (Euthynnus alletteratus) utilizando la región de control mitocondrial como marcador genético. Se analizaron más de 500 ejemplares distribuidos en seis localizaciones. Las muestras procedían de tres regiones principales: Mediterráneo (Túnez y España), Atlántico nororiental (Portugal y Senegal) y Atlántico suroriental (Côte d'Ivoire y Gabón). Se hallaron profundas diferencias genéticas entre las tres localizaciones: El árbol filogenético presentaba una asociación monofilética recíproca completa de los ejemplares en dos regiones principales: Portugal, España y Túnez; y Senegal, Côte d'Ivoire y Gabón. El nivel de diferenciación genética entre estas dos zonas es similar a las diferencias halladas entre especies del género Euthynnus. Estos resultados sugieren un escenario con dos especies de bacoreta en su distribución atlántica-mediterránea. Son necesarias más pruebas con otros marcadores genéticos no vinculados con datos morfológicos y neríticos para confirmar más estas dos especies putativas. Sin embargo, en base a estos resultados, puede considerarse una unidad de ordenación separada: i) Atlántico nororiental/Mediterráneo (Portugal, España y Túnez) y ii) Atlántico suroriental/nororiental (Senegal, Côte d'Ivoire y Gabón).N

Population genetic of Atlantic bonito in the north east Atlantic and Mediterranean

This study assesses the stock structure of Atlantic bonito (Sarda sarda) using the mitochondrial control region as a genetic marker. About 615 individuals distributed in seven locations were analyzed. Two of the locations were in the Mediterranean Sea (MD/BIL95) (Spain and Tunis), three in the northeast Atlantic (AT-NE/BIL94B) (Portugal, Tunis, Morocco and Mauritania), and one in the southeast Atlantic (AT-SE/BIL97) (Côte d’Ivoire). All these samples were obtained thanks to the participation of all authors in two Small Tuna Research Programs funded by ICCAT. The analysis of the genetic variability of the sequence of mitochondrial control regions depicts a clear heterogeneity among locations. The shared genetic pool that comprises the locations within the Mediterranean (Spain and Tunis), including also a sample from the northeast Atlantic (Portugal), is clearly different from the African locations (Senegal and Côte d’Ivoire). Moreover, these two African locations are also genetically differentiated between them. Morocco and Mauritania locations seems to be located in an intermediate situation between these two groups of locations. These results can be used to infer a management policy by ICCAT on the fisheries of this specie

Final report of the short-term contract for ICCAT SMYTP for the biological samples collection for growth, maturity and genetics studies – Year #2

This document is the final report of the second year of the short-term contract of the Small Tuna Year Program by ICCAT. In 2018, the Small Tuna Species Group decided to prioritize Little tunny (LTA) (Euthynnus alletteratus) Atlantic bonito (BON) (Sarda sarda) and Wahoo (WAH) (Acanthocybium solandri), based on their economic importance and the deficiency of knowledge of their biology. The objectives of the contract for three species were: i) Collect biological samples for estimating growth parameters, assessing the maturity and stock structure analysis (populations genetics), and ii) Conclude the analysis of the stock structure for at least one of the three species and provide preliminary results for the remaining. The obtained samples for growth, maturity and stock structure analysis was almost completed for Little tunny and Atlantic bonito, whereas for Wahoo the samples are scarce. The analysis of stock structure for Little tunny and Atlantic bonito revealed that the observed dif