Characterization of a Peruvian coastal fishery targeting the Pacific guitarfish Pseudobatos planiceps.

From December 2012 to June 2014, 796 Pacific guitarfish were caught in 183 fishing sets in northern Peru. Catch occurred in 86.3% of sets. Most individuals caught were mature with a bias toward males. The mean total length for females and males was 83.4 cm, and 91.1 cm, respectively. The capture per unit effort (CPUE) was 12.6 ± 3.4 guitarfish (km.12 h)-1. The length-weight relationships showed that this species presents a sexual dimorphism in growth. These results support the importance of Sechura Bay as a key area for this species. This study represents the first species-specific fishery data for the Pacific guitarfish.

Social wellbeing, values, and identity among Caiçara small-scale fishers in southeastern Brazil.

Although much in the lives of members of the Caiçara small-scale fishing communities of Lázaro and Saco da Ribeira in Ubatuba, southeastern Brazil would suggest hardship, that population expresses a surprising degree of satisfaction with life. In this paper, we use a social wellbeing lens as applied through an ethnographic, mixed methods approach to reflect on this overall sense that lives rooted in small-scale fishing are well worth living despite their many challenges. We see the classic maritime anthropology theme of identity at the heart of meaning and life satisfaction. Identity provides core aspects of how people engage with their realities and anchors values that are reference points in work and social relations. With reference to the relational nuances revealed by the social wellbeing perspective, however, we show that Caiçara and small-scale fishing identities are not monolithic, but reflect gender and other social positions, and personal and familial experiences. These experiences include grappling with the complex effects of economic, social, political, and environmental changes. We conclude by arguing that fisheries policy that seeks to prioritize human wellbeing would benefit by adopting a social wellbeing perspective. Fisheries policy could thereby take into account identity, values, and relational elements of social life that give meaning and a sense of belonging to small-scale fishers, while also recognizing the cross-cutting and often contradictory variations in human experience that arise from social and economic differences. This social fabric of small-scale fishers' lives shapes their intentions and actions and is thus a necessary complication to the practice of fisheries management that its proponents need to consider.

A tragedy of the commons case study: modeling the fishers king crab system in Southern Chile.

Illegal fishing in small-scale fisheries is a contentious issue and resists a straightforward interpretation. Particularly, there is little knowledge regarding cooperative interactions between legal and illegal fishers and the potential effects on fisheries arising from these interactions. Taking the Chilean king crab (Lithodes santolla; common name centolla) fishery as a case study, our goal is twofold: (i) to model the effect of illegal-legal fishers' interactions on the fishery and (ii) analyze how management and social behavior affect fishery's outcomes. We framed the analysis of this problem within game theory combined with network theory to represent the architecture of competitive interactions. The fishers' system was set to include registered (legal) fishers and unregistered (illegal) fishers. In the presence of unregistered fishers, legal fishers may decide to cooperate (ignoring the presence of illegal fishers) or defect, which involves becoming a "super fisher" and whitewashing the captures of illegal fishers for a gain. The utility of both players, standard fisher and super fisher depend on the strategy chosen by each of them, as well as on the presence of illegal fishers. The nodes of the network represent the legal fishers (both standard and super fishers) and the links between nodes indicate that these fishers compete for the resource, assumed to be finite and evenly distributed across space. The decision to change (or not) the adopted strategy is modeled considering that fishers are subjected to variable levels of temptation to whitewash the illegal capture and to social pressure to stop doing so. To represent the vital dynamics of the king crab, we propose a model that includes the Allee effect and a term accounting for the crab extraction. We found that the super fisher strategy leads to the decrease of the king crab population under a critical threshold as postulated in the tragedy of the commons hypothesis when there are: (i) high net extraction rates of the network composed of non-competing standard fishers, (ii) high values of the extent of the fishing season, and (iii) high density of illegal fishers. The results suggest that even in the presence of super fishers and illegal fishers, the choice of properly distributed fishing/closure cycles or setting an extraction limit per vessel can prevent the king crab population from falling below a critical threshold. This finding, although controversial, reflects the reality of this fishery that, for decades, has operated under a dynamic in which whitewashing and super fishers have become well established within the system.

Spatial dynamics of Amazonian commercial fisheries: an analysis of landscape composition and fish landings / Dinâmica espacial da pesca comercial amazônica: uma análise da composição da paisagem e dos desembarques de pescado

Amazonian commercial fishing is artisanal, and landings can be influenced by the flood pulse, the consumer market, the level of exploitation of species, habitat quality and vegetation cover. In this study, landscape variables and the river level were evaluated as possible drivers in the composition of catches landed in three regions of the SolimõesAmazon River. Fish landing data were collected in the upper and lower Solimões River and lower Amazon River. Fishing locations were mapped with information from fishers, civil defense departments and from the literature. Information related to river level and landscape was acquired from databases available online. Maps with the the radius of action of the fishing fleet and the quantification of landscape variables were made for periods of high and low-water, and non-metric multidimensional scaling analysis (nMDS) with catches by species, by region and hydrological period were performed. The largest operating radius of the fishing fleet was of 1,028 km and was identified in the lower Amazon River, which is probably due to the larger size of the consumer market, vessel characteristics and level of exploitation of the species near the landing center. The proportion of vegetation cover was reduced from 87% in the upper stretches of the Solimões River to 46% in the lower stretches. The upper and lower Solimões River regions presented a greater variety of species in the composition of landings. It was identified that the composition of landings between the three analyzed regions possibly varied according to the availability of habitats, indicating the importance of landscape variables for fish landings.

A pesca comercial amazônica é artesanal e os desembarques podem ser influenciados pelo pulso de inundação, mercado consumidor, nível de explotação das espécies, qualidade do hábitat e cobertura da vegetação. Nesse estudo, avaliamos as variáveis da paisagem e o nível do rio como possíveis impulsionadores na composição das capturas desembarcadas em três regiões do rio Solimões-Amazonas. Os dados de desembarque de pescado foram coletados no Alto e Baixo rio Solimões e Baixo rio Amazonas. Os locais de pesca foram mapeados com informações dos pescadores, da defesa civil e literatura. As informações relacionadas ao nível do rio e a paisagem foram adquiridas em bancos de dados disponíveis online. Mapas com o raio de atuação da frota pesqueira e a quantificação das variáveis da paisagem foram elaborados para períodos de águas altas e baixas e as análises de escalonamento multidimensional não-métrico (nMDS) com as capturas por espécie, por região e período hidrológico foram realizadas. O maior raio de atuação da frota pesqueira foi de 1.028 km e foi identificado no Baixo rio Amazonas provavelmente devido ao maior tamanho do mercado consumidor, características das embarcações e nível de explotação das espécies próximo do centro de desembarque. A proporção de cobertura de vegetação teve uma redução de 87% no trecho superior do rio Solimões para 46% no trecho inferior. As regiões do Alto e Baixo rio Solimões apresentaram maior variedade de espécies na composição dos desembarques. Foi identificada que a composição dos desembarques entre as três regiões analisadas variou possivelmente conforme a disponibilidade de hábitats, indicando a importância das variáveis da paisagem para os desembarques de pescado.

The consumption of fish by the riverine population of the lower Solimões River, Amazonas, Brazil / O consumo de pescado de uma população ribeirinha do baixo rio Solimões, Amazonas, Brasil

The riverine population of the Amazon Basin are among the largest consumers of fish in the world, but the consumption patterns could be regionally distinct. Moreover, their total fish catches are not fully known. The objective of this work was to estimate the per capita fish consumption of the riverine people that inhabit the Paciência Island (Iranduba, Amazonas), where there is a fishing agreement in force. A total of 273 questionnaires were applied during the first two weeks of each month between April 2021 and March 2022. The sample unit was the residences. The questionnaire contained questions about the species captured and their quantities. Consumption was calculated by dividing the average monthly capture with the average number of residents per household interviewed, which was multiplied by the number of questionnaires applied. Thirty groups of consumed fish species belonging to 17 families and 5 orders were recorded. The total catch was 3,388.35 kg and the highest monthly catch was 602.60 kg during the falling-water season in October. Daily per capita fish consumption averaged 66.13 ± 29.21 g/day, with a peak of 116.45 g/day during the falling-water season in August. The high fish consumption rate highlighted the importance of fisheries management to food security and the maintenance of the community's lifestyle.

As populações amazônicas são uma das maiores consumidoras de pescado do mundo, contudo os padrões de consumo podem ser regionalmente distintos. Além disso, as capturas totais não são totalmente conhecidas. O objetivo do trabalho foi estimar o consumo per capita e as capturas de pescado por ribeirinhos residentes na Ilha da Paciência (Iranduba, Amazonas), onde há um acordo de pesca vigente. Foram aplicados no total 273 questionários durante as duas primeiras semanas de cada mês entre abril de 2021 e março de 2022. A unidade amostral foram as residências. O questionário continha perguntas sobre as espécies capturadas e respectivas quantidades. O consumo foi calculado pela divisão entre a média de captura mensal com a média de moradores por residência entrevistada que foi multiplicada pelo número de questionários aplicados. Foram registrados 30 grupos de espécies de peixes consumidos pertencentes a 17 famílias e 5 ordens. A captura total foi de 3.388,35 kg e a maior captura mensal foi de 602,60 kg durante a vazante no mês de outubro. O consumo de pescado per capita diário foi em média 66,13 ± 29,21 g/dia, com pico de 116,45 g/dia durante a vazante no mês de agosto. A alta taxa de consumo de pescado mostra a importância do manejo pesqueiro para a segurança alimentar e a manutenção do estilo de vida da comunidade.

Fishers' knowledge on a large floodplain river in South America. Contributions for sustainable management of inland fisheries.

This study presents a comparison between fishers' knowledge and fiscal records about the structure of inland fisheries in the Paraná River (Argentina). First of all, we characterized the fishing population according to the main demographic and economic indicators, identifying two different fishing areas: the northern and southern sections in the lower La Plata basin. Secondly, we carried out a comparative analysis of fiscal fishery records (from two commercial sets: 1930-1984 and 2011-2019) and local fishers' knowledge on inland commercial fisheries (frequency of occurrence and abundance). Finally, we contrasted current fishing regulations (allowed meshes and boats, fishing prohibitions, exports) to fishers' effective practices. The study area included 52 sites located along the floodplain of the middle and lower sections of the Paraná River, in the province of Santa Fe. Socioeconomic analyses identified two different groups of fishers throughout the river corridor. Results showed that fishers have detailed knowledge on nomenclature, ecology, reproductive strategy, habitat distribution, and usefulness of commercial fish species. By contrasting fishers' knowledge with fiscal records, we found similar and complementary information about the changes in abundance and frequency of occurrence in fisheries. These results highlight the need of including local knowledge as an outstanding source of information for well-planned management of fishing programs and sustainable policies. Supplementary Information: The online version contains supplementary material available at 10.1007/s11160-022-09722-x.

SELECTIVIDAD DE RED DE ENMALLE PARA CAPTURA DE BOCACHICO (Prochilodus magdalenae, Prochilodontidae) EN LA CIÉNAGA DE ZÁRATE / Gillnet selectivity for catching bocachico (Prochilodus magdalenae, Prochilodontidae) In Zarate Swamp

RESUMEN La estimación precisa de curvas de selectividad de redes de enmalle en una población de peces es un requisito importante para la sostenibilidad de los stocks explotados. Sin embargo, los trabajos de selectividad para artes de pesca que operan en ecosistemas continentales de Colombia son muy escasos. Este estudio determinó los parámetros de selectividad de redes de enmalle utilizadas en la captura del bocachico (Prochilodus magdalenae). El diseño experimental evaluó tres tamaños de malla (5,72; 6,35 y 8,89 cm) y las capturas se realizaron en diferentes sitios de pesca de la ciénaga de Zárate. Con la utilización del método SELECT se estimaron los parámetros de selectividad y mediante un análisis de Kruskall Wallis se determinaron las diferencias en la captura por unidad de esfuerzo. Además, el tamaño de malla óptimo fue calculado a partir del principio de similaridad geométrica de Baranov. Los resultados muestran que el modelo normal con varianza proporcional al tamaño de malla es el que mejor ajuste presentó para la captura de bocachico. Las longitudes modales calculadas con el modelo normal con varianza proporcional al tamaño de malla fueron 22,90, 25,45 y 35,63 cm para tamaños de malla de 5,72, 6,35 y 8,89 cm, respectivamente. El tamaño de malla óptimo calculado fue 6,99 cm. Los resultados indican que las redes con tamaños de malla de 5,72 cm e inferiores tienen un efecto sobre la estructura de tamaños del bocachico. Estas redes requieren ser priorizadas en la formulación de medidas de manejo basadas en la ordenación de este arte de pesca, lo que permitirá la sostenibilidad de la pesquería.

ABSTRACT Accurate estimation of gillnet selectivity curves in a fish population is an important requirement for the sustainability of exploited stocks. However, selectivity studies for fishing gear operating in Colombia's inland ecosystems is very rare. This study determined the gillnet selectivity parameters used in the catch of the bocachico (Prochilodus magdalenae). The experimental design evaluated three mesh sizes (5.72, 6.35 and 8.89 cm) and the catches were made in different fishing sites at the Zárate swamp. With the use of the SELECT method, the selectivity parameters were estimated and the Kruskall Wallis test determined the differences in the catch per unit effort. Furthermore, the optimal mesh size was calculated from Baranov's principle of geometric similarity. The results show that the normal model (scale) presented the best fit for the catch of bocachico. The modal lengths calculated with the normal scale model were 22.90, 25.45, and 35.63 cm for mesh sizes of 5.72, 6.35, and 8.89 cm, respectively. The calculated optimal mesh size was 6.99 cm. The results indicate that nets with mesh sizes of 5.72 cm and lower influences the size structure of the bocachico. These nets need to be prioritized in the formulation of management measures based on the regulation of this fishing gear, which will allow the sustainability of the fishery.

Pantanals fish native meatballs has the nutritional values increased with the use of pequi in its recipe

The s tudy aimed to evaluate whether the addition of pequi increases the nutritional v alue of meatballs made with piranha and pacu fillets. Piranhas were obtained fro m the colony of fishermen; pacu with the fish farmer and the pequis were collected in nature. Fish were filleted and triturated, and the result ing masses were used to prepare 4 types of meatballs: piranha fillet with 2.0% pequi pulp, piranha fillet without pequi pulp, pacu fillet with w ith 2.0% pequi pulp, and pacu fillet without pequipulp. After preparation, accep tance, purchase intention and frequency of consumption were evaluated with untra ined tasters. Chemical composition parameters evaluated were crude protein, lipi ds, ash, moisture, carotenoids and antioxidant activity. Results of acce ptability for all formulations were similar. The chemical composit ion of piranha meatballs presented differences (p<0.05) for lipids and carotenoi ds. Pacu meatballs showed no difference (p>0.05) for moisture, carotenoids,and a ntioxidant activity. The addition of pequi did not alter the organoleptic c haracteristics, however increased the nutritional values, therefore, it can add value to the product to be marketed and be more nutritionally attractive to the consumer.(AU)

Pantanal's fish native meatballs has the nutritional values increased with the use of pequi in its recipe

The study aimed to evaluate whether the addition of pequi increases the nutritional value of meatballs made with piranha and pacu fillets. Piranhas were obtained from the colony of fishermen; pacu with the fish farmer and the pequis were collected in nature. Fish were filleted and triturated, and the resulting masses were used to prepare 4 types of meatballs: piranha fillet with 2.0% pequi pulp, piranha fillet without pequi pulp, pacu fillet with with 2.0% pequi pulp, and pacu fillet without pequi pulp. After preparation, acceptance, purchase intention and frequency of consumption were evaluated with untrained tasters. Chemical composition parameters evaluated were crude protein, lipids, ash, moisture, carotenoids and antioxidant activity. Results of acceptability for all formulations were similar. The chemical composition of piranha meatballs presented differences (p < 0.05) for lipids and carotenoids. Pacu meatballs showed no difference (p > 0.05) for moisture, carotenoids, and antioxidant activity. The addition of pequi did not alter the organoleptic characteristics, however increased the nutritional values, therefore, it can add value to the product to be marketed and be more nutritionally attractive to the consumer.(AU)

Habitat use and nursery evaluation for the longnose stingray Hypanus guttatus (Bloch & Schneider, 1801) using vertebral microchemistry.

Here, we use vertebral microchemistry to investigate the habitat use patterns of the longnose stingray Hypanus guttatus in the northern and northeastern regions of Brazil, and to evaluate the existence of potential nurseries of the species. Samples were collected in Maranhão, Rio Grande do Norte and Pernambuco states between 2008 and 2019. Trace element concentrations of Ba:Ca, Mg:Ca, Mn:Ca and Sr:Ca in vertebrae were determined through laser ablation inductively coupled plasma mass spectrometry. We used one-step permutational ANOVAs to evaluate multi and single-element differences in element:Ca ratios among life stages and sexes across and within sites. Element signatures differed among all sites for both single and multi-element settings. However, there were few differences among life stages within sites, except for Mn:Ca between life stages for Maranhão state, and between sexes for Sr:Ca for both Pernambuco and Rio Grande do Norte, and Ba:Ca for Rio Grande do Norte. Furthermore, all multi and single-element analyses across locations were significant and highlight the strong differences by sites. We also performed a nonmetric multidimensional scaling analysis, which demonstrated the strong differences for samples from Rio Grande do Norte and the other two sites. By analysing the lifetime transects of each sample, we observed that there was little variation in all element:Ca ratios within sites. Therefore, we argue that the longnose stingray likely does not display extensive habitat use shifts and fulfils much of its life cycle within each area. Finally, we obtained no evidence of nurseries for any site and suggest this is likely a pattern across the species distribution. Future studies investigating habitat use with samples from larger specimens (disc width > 90 cm, >15 years) are needed to better understand the species habitat use patterns across all size ranges.

Predicting potential compliance of small-scale fishers in Brazil: The need to increase trust to achieve fisheries management goals.

Many global management and conservation initiatives fail to prevent overfishing either because they do not plan for local engagement, surveillance, and enforcement, and/or because they fail to include alternatives for short-term losses. Thus, these initiatives do not gain support among fishers. In this study, we interviewed fishers to investigate their stated behavior toward fisheries regulations. We assessed possible (non)compliant behavior under scenarios where fishers would face a moratorium on some of their target species. Additionally, we investigated the consequences of such a moratorium on the food web if it were to lead to fishing alternative species. Using data from two Brazilian coastal sites, we found that younger fishers and those who demonstrated a trustworthy relationship with stakeholders were inclined to comply with the rules. The level of potential compliance also varied between the studied places, probably due to unidentified local idiosyncrasies. Fishers tended to trust community actors (e.g., the leader or head of the fishing community) more than institutional actors (e.g., environmental agencies). When fishers were asked why they would choose specific replacement species in the event of a moratorium, they most often cited expected profitability and ease of capture as reasons. Fishers also tended to say that they would replace endangered species with species in the same and/or lower trophic categories. We suggest working toward stronger stakeholder engagement, given that an overall sense of trust in a community appears to be an important asset toward successful management. Higher levels of trust could promote more transparency in the decision-making process, which could facilitate information dissemination, awareness, and the need for compliance. The mixed methods approach used here could help predict responses to new and existing management policies and support adaptive fisheries management.

Growth Modeling of the Giant Electric Ray Narcine entemedor in the Southern Gulf of California: Analyzing the Uncertainty of Three Data Sets.

The age and growth rate of the giant electric ray, Narcine entemedor, was estimated using growth bands deposited in the vertebral centra of 245 specimens. Differences in size and age distribution were found between the sexes, a pattern that suggests the annual deposition of band pairs, possibly occurring in April. Multimodel inference and back-calculation were performed to three age data sets of females considering their reproductive cycle and time of capture, among which the von Bertalanffy growth function was found to be the most appropriate (L∞ = 81.87 cm TL, k = 0.17 year-1). Our research supports the idea that age can be determined via biological features such as birth date and growth band periodicity. We concluded that N. entemedor is of a moderate body size, moderate longevity and is a fast-growing elasmobranch species.

Mercury dynamics in macroinvertebrates in relation to environmental factors in a highly impacted tropical estuary: Buenaventura Bay, Colombian Pacific.

The environmental health of Buenaventura Bay, a highly impacted tropical estuary, is influenced by numerous human activities, including mining upstream. Large- and small-scale fishing plays an important role in the local economy, so we investigated the dynamic processes of bioaccumulation of mercury at basal trophic levels. Four samples were taken at each of the four locations in Buenaventura Bay during each of the four seasons of 2015. We measured the total mercury content (T-Hg, dry weight) in sediments and in muscle tissue across 17 macroinvertebrate species. The most abundant were the blue crab (C. arcuatus) and the mantis shrimp (S. aculeata aculeata). Blue crab showed an average muscle T-Hg value ​​exceeding the limit of 0.2 g·g-1, which is the maximum T-Hg level suggested for food consumption by vulnerable humans and populations: pregnant women, children, and the community that feeds from this source of protein on a daily basis. It was found that, 6.22% of individuals exceeded the 0.5 g·g-1 level, which is the maximum T-Hg level suggested for food consumption by the general population: the population that consumes it sporadically. Significantly high values ​​of T-Hg in blue crab and mantis shrimp occurred during low salinity conditions in the estuary, suggesting that Hg mainly originates from river runoff during the rainy season. Nevertheless, the biota-sediment accumulation factor (BSAF) was favored in high salinity, which could mean greater availability of Hg for higher levels of the estuarine food web in the dry season and in marine waters. In general, the T-Hg levels in some samples exceeded 0.2 g·g-1. Therefore this pollutant must be monitored due to its biomagnification potential and as a threat to human health, especially that for the local population of fishermen and their families.

Age, growth, reproduction and management of Southwestern Atlantic's largest and endangered herbivorous reef fish, Scarus trispinosus Valenciennes, 1840.

The Brazilian-endemic greenbeack parrotfish, Scarus trispinosus Valenciennes, 1840, is the largest herbivorous reef fish in the South Atlantic. Following the sharp decline of large carnivorous reef fishes, parrotfishes (Labridae: Scarinae) were progressively targeted by commercial fisheries in Brazil, resulting in a global population decline of 50% for S. trispinosus. Most of its remnant population is concentrated in the Abrolhos Bank, where the present study was conducted. We present novel information on age, growth and the reproductive cycle of S. trispinosus, based on 814 individuals obtained from commercial fisheries' landings and scientific collections, between 2010 and 2013. Sex ratio was biased toward females (1:8), and spawning occurred year-round with discrete peaks in February-March and June-December. Increment analysis indicated annual deposition of growth rings in otoliths, which presented 1-22 rings. The asymptotic length at which growth is zero (L ∞) was estimated from a Bayesian logistic regression at 85.28 cm, growth rate (K) at 0.14 year-1, and the theoretical age at zero size (t 0) at 0.16. Subregional demographic structuring was detected, with predominance of slower-growing individuals in shallower inshore reefs and predominance of faster-growing and older individuals in deeper offshore sites. We demonstrate that S. trispinosus is highly vulnerable to over-exploitation due to its large size, long live and slow-growth, and review the management measures proposed since its Red List assessment in 2012.

Efficiently enforcing artisanal fisheries to protect estuarine biodiversity.

Artisanal fisheries support millions of livelihoods worldwide, yet ineffective enforcement can allow for continued environmental degradation due to overexploitation. Here, we use spatial planning to design an enforcement strategy for a pre-existing spatial closure for artisanal fisheries considering climate variability, existing seasonal fishing closures, representative conservation targets and enforcement costs. We calculated enforcement cost in three ways, based on different assumptions about who could be responsible for monitoring the fishery. We applied this approach in the Patos Lagoon estuary (Brazil), where we found three important results. First, spatial priorities for enforcement were similar under different climate scenarios. Second, we found that the cost and percentage of area enforced varied among scenarios tested by the conservation planning analysis, with only a modest increase in budget needed to incorporate climate variability. Third, we found that spatial priorities for enforcement depend on whether enforcement is carried out by a central authority or by the community itself. Here, we demonstrated a method that can be used to efficiently design enforcement plans, resulting in the conservation of biodiversity and estuarine resources. Also, cost of enforcement can be potentially reduced when fishers are empowered to enforce management within their fishing grounds.

Understanding dive behavior of artisanal fishermen divers of the Yucatán Peninsula.

INTRODUCTION/BACKGROUND: Artisanal fishermen dive for sustenance. The lifetime prevalence of decompression sickness (DCS) in this population is alarmingly high. We wanted to understand the level of decompression stress fishermen in this region of the Yucatán experience in their daily fishing effort. We used a mathematical model to quantify nitrogen-loading in a nine-tissue compartment model. MATERIALS AND METHODS: Approved by the UCLA IRB 2 #13-000532, this study was conducted during fishing seasons 2012 through 2017. Diving fishermen were instructed to attach dive recorders to their waists every fishing day during the study period. Sensus Ultra dive recorders (ReefNet Inc.), with an accuracy of ±1 foot of seawater (fsw), 0.304 meters, and an activation depth of 10 fsw, 3.04 meters, were used to record dive parameters. Sampling interval was set to 10 seconds. A program in RStudio was created to extract the dive profiles of each fishing day and curtail into single-line outputs: pressure, time, date, start of dive and end of dive. An exponential decay formula was used to calculate the nitrogen-loading pressures for nine theoretical tissue compartments. Final nitrogen pressure, controlling compartments, decompression stop and time at stop were calculated. RESULTS: Fishermen completed 4,961 dives over 1,758 diving days during the study period. The 40-minute compartment controlled most of the dives. The 80-minute compartment controlled 5%-20% of dives two through five. Decompression stop times for the last dive ranged from one minute to 190 minutes. Most of the required stop time observed was seen at depths of 1-15 fsw.

Gillnet selectivity for forage fish with emphasis on manjuba (Opisthonema oglinum) in an estuary in the northeast of Brazil / Seletividade de redes de emalhar para peixes forrageiros com ênfase para Opisthonema oglinum em um estuário do nordeste do Brasil

The selectivity of gillnets for the inhabiting forage fish community in the Santa Cruz Channel (PE, Brazil) was estimated an experiment using three mesh sizes (30, 40 and 50 mm). The SELECT was used to estimate retention curves through four models: normal location, normal scale, lognormal and gamma. Aggregated as catches in all fisheries, 28 species were identified. Selectivity parameters for species Opisthonema oglinum, Anchovia clupeoides and Cetengraulis edentulous were estimated. The normal scale model gave the best fit for all species studied. In the case of O. oglinum fishing in the Santa Cruz Channel the catches of young individuals are particularly significant in gillnets with a 30 mm mesh size. However, a possible increase in mesh size indicates little change in the length structure of the catch for larger sizes, but catches would certainly be reduced. Thus, regulations with increased mesh size should result in non-viability of fishing continuity with reduced catches.

As seletividades de redes de emalhar para peixes forrageiros que habitam o Canal de Santa Cruz (PE, Brasil) foram estimadas a partir de um experimento com três tamanhos de malha (30, 40 e 50 mm). O SELECT foi usado para estimar as curvas de retenção através de quatro modelos: normal com dispersão fixa, normal com dispersão variável, lognormal e gama. No total foram identificadas 28 espécies. Os parâmetros de seletividade foram estimados para as espécies Opisthonema oglinum, Anchovia clupeoides e Cetengraulis edentulus. O modelo normal com dispersão variável foi de melhor ajuste para todas as espécies. No caso da pesca da O. oglinum no Canal de Santa Cruz verificou-se que as quantidades capturadas de indivíduos jovens são particularmente mais expressivas na rede de emalhar com a malha de 30 mm. No entanto, um eventual aumento da malha indica um desvio pouco significativo da estrutura de comprimento da captura para maiores tamanhos, mas as capturas certamente seriam reduzidas. Assim, regulamentações com aumento de malha devem resultar em inviabilidade da continuidade da pesca com diminuição das capturas.

Gillnet selectivity for forage fish with emphasis on manjuba (Opisthonema oglinum) in an estuary in the northeast of Brazil / Seletividade de redes de emalhar para peixes forrageiros com ênfase para Opisthonema oglinum em um estuário do nordeste do Brasil

The selectivity of gillnets for the inhabiting forage fish community in the Santa Cruz Channel (PE, Brazil) was estimated an experiment using three mesh sizes (30, 40 and 50 mm). The SELECT was used to estimate retention curves through four models: normal location, normal scale, lognormal and gamma. Aggregated as catches in all fisheries, 28 species were identified. Selectivity parameters for species Opisthonema oglinum, Anchovia clupeoides and Cetengraulis edentulous were estimated. The normal scale model gave the best fit for all species studied. In the case of O. oglinum fishing in the Santa Cruz Channel the catches of young individuals are particularly significant in gillnets with a 30 mm mesh size. However, a possible increase in mesh size indicates little change in the length structure of the catch for larger sizes, but catches would certainly be reduced. Thus, regulations with increased mesh size should result in non-viability of fishing continuity with reduced catches.(AU)

As seletividades de redes de emalhar para peixes forrageiros que habitam o Canal de Santa Cruz (PE, Brasil) foram estimadas a partir de um experimento com três tamanhos de malha (30, 40 e 50 mm). O SELECT foi usado para estimar as curvas de retenção através de quatro modelos: normal com dispersão fixa, normal com dispersão variável, lognormal e gama. No total foram identificadas 28 espécies. Os parâmetros de seletividade foram estimados para as espécies Opisthonema oglinum, Anchovia clupeoides e Cetengraulis edentulus. O modelo normal com dispersão variável foi de melhor ajuste para todas as espécies. No caso da pesca da O. oglinum no Canal de Santa Cruz verificou-se que as quantidades capturadas de indivíduos jovens são particularmente mais expressivas na rede de emalhar com a malha de 30 mm. No entanto, um eventual aumento da malha indica um desvio pouco significativo da estrutura de comprimento da captura para maiores tamanhos, mas as capturas certamente seriam reduzidas. Assim, regulamentações com aumento de malha devem resultar em inviabilidade da continuidade da pesca com diminuição das capturas.(AU)

Seasonal dynamic of amazonian small-scale fisheries is dictated by the hydrologic pulse / A dinâmica sazonal das pescarias de pequena escala na Amazônia é definida pelo pulso hidrológico

This study analyzed the dynamic of an Amazonian small-scale fishery, and as it is associated to the hydrological cycle. Landing data were daily collected from February/2007 to January/2008 at the Panairzinha harbor in Manacapuru city, Amazonas – Brazil (3º 18’33”S e 60º 33’21”W). The results showed that the active fleet in the Lago Grande consists of motorized canoes and fishing boats. The first group being greater than the second in number. The average of fish landed was 274.15 ton.year-1. Occurring lower production in the hydrological periods of rising/flood and high production in the receding/drought. The main fish species landed were: Colossoma macropomum (tambaqui = 17.8%), Cichla monoculus (tucunaré = 15.5%), Prochilodus nigricans (curimatã = 12.2%), Astronotus ocellatus (acará-açu = 8.7%) and Osteoglossum bicirrhosum (arowana = 8.4%), where gillnets were predominantly (97%) in these catches. It was observed that the seasonality of the Solimões River, directly influences the fisheries and the availability of fish in the environment. In this sense, decisions involving fishing management of this region should be planned aiming to ensure the sustainability of local fisheries, considering as essential the relation between fish, the environment and the socioeconomic aspects inherent with these small-scale fisheries.

O presente estudo analisou a dinâmica de uma pescaria de pequena escala na Amazônia, em associação com o ciclo hidrológico. Dados de desembarque pesqueiro foram coletados, diariamente, no período de fevereiro/2007 a janeiro/2008, no Porto Panairzinha em Manacapuru, Amazonas – Brasil (3º 18’33”S e 60º 33’21”W). Os resultados mostraram que a frota atuante no Lago grande é composta por canoas motorizadas e barcos de pesca. Sendo o primeiro superior ao segundo em número. A média do pescado desembarcado foi de 274,15 ton.ano-1. Ocorrendo uma menor produção nos períodos de enchente/cheia e maior na vazante/seca. As principais espécies desembarcadas foram: Colossoma macropomum (tambaqui = 17,8%), Cichla monoculus (tucunaré = 15,5%), Prochilodus nigricans (curimatã = 12,2%), Astronotus ocellatus (acará-açu = 8,7%) e Osteoglossum bicirrhosum (aruanã = 8,4%), predominando a malhadeira (97%) nessas capturas. Foi observado que a sazonalidade do Rio Solimões, influencia diretamente nas pescarias e na disponibilidade do pescado. Nesse sentido, decisões envolvendo o manejo pesqueiro nessa região devem adotar medidas que assegurem a sustentabilidade da pesca local, considerando como essencial a relação entre o peixe, o ambiente e aspectos socioeconômicos das pescarias de pequena escala.