Ethnoecology and socioeconomic around an artificial reef: the case of artisanal fisheries from southeastern Brazil / Etnoecologia e socioeconomia em torno de um recife artificial: o caso da pesca artesanal do sudeste do Brasil

Abstract: The objective of this study is to describe the ethnoecological aspects, valorization, and commercialization of target species caught by artisanal fishers on the northern coast of Rio de Janeiro, southeastern Brazil. The data were obtained through semi-structured interviews conducted with 60 fishers from the fishing community of Guaxindiba (21°29'S, 41°00'W), which is associated with the Z-1 fishers' colony. Eighty-nine species were cited by the fishers and 44.1% are important commercial fish in the region. The fishers cited five distinct zones used to fish: border zone (68 species), estuary (41 spp.), artificial reef (27 spp.), "malacacheta" (24 spp.), and open ocean (10 spp.). The fishery resources were classified according to their gastronomic and economic characteristics: primary fish (35 spp.), secondary fish (32 spp.), mixed fish (10 spp.), discarded fish (7 spp.), and fish used as bait (5 spp.). The price of the target species increases along the production chain due to the greater number of people involved, processing costs, and improvement of the product. The data from this study can contribute to local fisheries management and point out to the use of artificial reefs in the maintenance of fishery resources in northern Rio de Janeiro.

Resumo: O objetivo desse estudo é descrever os aspectos etnoecológicos, a valoração e a forma de comercialização das espécies-alvo capturadas na pesca artesanal praticada na costa norte do Rio de Janeiro, sudeste do Brasil. Os dados foram obtidos a partir de entrevistas semiestruturadas realizadas com 60 pescadores da comunidade pesqueira Guaxindiba (21°29'S, 41°00'O), vinculados à colônia de pescadores Z-1. Oitenta e nove espécies foram citadas pelos pescadores e 44,1% desse total são importantes para o comércio da região. Os pescadores citaram cinco zonas distintas que são utilizadas para a pesca: zona da "borda" (68 espécies), estuário (41 spp.), recife artificial (27 spp.), "malacacheta" (24 spp.) e mar aberto (10 spp,). Os recursos pesqueiros foram classificados de acordo com suas características gastronômicas e econômicas: pescado-de-primeira (35 spp.), pescado-de-segunda (32 spp.), pescado-mistura (10 spp.), pescado-de-descarte (7 spp.) e pescado-isca (5 spp.). O preço das espécies-alvo aumenta ao longo da cadeia produtiva em decorrência do maior número de pessoas envolvidas, dos gastos com insumos e do processo de beneficiamento do pescado. Os dados desse estudo podem contribuir para o manejo da pesca local e apontam para o uso de recifes artificiais na manutenção dos recursos pesqueiros no norte do Rio de Janeiro.

Management proposal based on the timing of oral incubation of eggs and juveniles in the sentinel species Genidens genidens (Siluriformes: Ariidae) in a tropical estuary

Ariids such as Genidens genidens are particularly susceptible to overfishing because of their complex reproductive mechanisms, which result in slow replenishment of stocks. In this study, we obtained data about the reproductive ecology of the catfish G. genidens in the Guanabara Bay estuary, Rio de Janeiro, Brazil, providing supporting information for management of its fishery. The sex ratio, mean size of each sex at first sexual maturation, and female fecundity were determined and the reproductive period was characterized. The males:females ratio was 1:2. The fecundity is low and increases proportionally to the females' growth in total length and weight. The breeding season occurs during the warmest months of the year, with spawning extending from October through March and incubation from December through April. Sexual maturation is late, with males maturing at a larger size than females. Skipping spawning was also identified in females. Based on the reproductive biology, it is suggested that the catch be restricted to individuals larger than 20 cm, considering the L75 of the males, and that fishing be prohibited from December through March, to include the main period of spawning season by females and oropharyngeal incubation by males.(AU)

Ariídeos, como Genidens genidens, são particularmente suscetíveis à sobrepesca devido a seus complexos mecanismos reprodutivos, que resultam em uma reposição lenta dos estoques. Neste estudo, obtivemos dados sobre a ecologia reprodutiva do bagre G. genidens no estuário da Baía de Guanabara, Rio de Janeiro, Brasil, fornecendo subsídios para seu manejo pesqueiro. A proporção sexual, o tamanho médio de primeira maturação sexual de cada sexo e a fecundidade das fêmeas foram determinados e o período reprodutivo caracterizado. A proporção machos:fêmeas foi de ١:2. A fecundidade é baixa e aumenta proporcionalmente ao crescimento das fêmeas em comprimento total e no peso. O período reprodutivo ocorre durante os meses mais quentes do ano, com a desova se estendendo de outubro a março e a incubação de dezembro a abril. A maturação sexual é tardia, com machos amadurecendo em tamanho maior que as fêmeas. Também foi identificado nas fêmeas adiamento da desova. Com base na biologia reprodutiva, sugere-se que a captura seja restrita a indivíduos maiores que 20 cm, considerando a C75 dos machos, e que a pesca seja proibida de dezembro a março, para incluir o período principal de época de desova das fêmeas e incubação orofaríngea dos machos.(AU)

Shell shape variation of queen conch Strombus gigas (Mesograstropoda: Strombidae) from Southwest Caribbean / Variación de la conformación de la concha del caracol reina Strombus gigas (Caenogastropoda: Strombidae) del Caribe suroccidental

Abstract:The endangered species Strombus gigas is a marine gastropod of significant economic importance through the Greater Caribbean region. In contrast to phenotypic plasticity, the role of genetics on shell variations in S. gigas has not been addressed so far, despite its importance in evolution, management and conservation of this species. This work used geometric morphometrics to investigate the phenotypic variation of 219 shells of S. gigas from eight sites of the Colombian Southwest Caribbean. Differences in mean size between sexes and among sites were contrasted by analysis of variance. Allometry was tested by multivariate regression and the hypothesis of common slope was contrasted by covariance multivariate analysis. Differences in the shell shape among sites were analyzed by principal component analysis. Sexual size dimorphism was not significant, whereas sexual shape dimorphism was significant and variable across sites. Differences in the shell shape among sites were concordant with genetic differences based on microsatellite data, supporting its genetic background. Besides, differences in the shell shape between populations genetically similar suggest a role of phenotypic plasticity in the morphometric variation of the shell shape. These outcomes evidence the role of genetic back- ground and phenotypic plasticity in the shell shape of S. gigas. Thus, geometric morphometrics of shell shape may constitute a complementary tool to explore the genetic diversity of this species. Rev. Biol. Trop. 64 (4): 1585-1595. Epub 2016 December 01.

Resumen:La especie en peligro, Strombus gigas, es un gastrópodo marino de importancia económica en la región del Gran Caribe. En contraste con la plasticidad fenotípica, el papel de la genética en la variación de la concha en S. gigas no ha sido abordado hasta ahora, a pesar de su importancia evolutiva, manejo y conservación. Este trabajo utilizó la morfometría geométrica para investigar la variación fenotípica de la concha de S.gigas en ocho sitios del suroeste del Caribe colombiano. Las diferencias en el tamaño promedio entre sexos y sitios se contrastaron mediante análisis de varianza. La alometría se evaluó mediante regresión multivariada y la hipótesis de pendientes similares se contrastó mediante un análisis multivariado de covarianza. Las diferencias en la conformación de las conchas entre sitios se exploraron mediante análisis de componentes principales. El dimorfismo sexual en el tamaño no fue significativo, mientras que el dimorfismo sexual en la conformación fue significativo y variable entre los sitios. Las diferencias en la conformación de la concha entre sitios fueron concordantes con diferencias genéticas basadas en microsatélites, lo cual apoya su base genética. Además, las diferencias en conformación de la concha entre poblaciones genéticamente similares sugieren un papel de la plasticidad fenotípica en la variación morfométrica de la conformación de la concha. Estos resultados evidencian el papel de la genética y la plasticidad fenotípica en la conformación de la concha de S. gigas. Por lo tanto, la morfometría geométrica de la conformación de la concha puede constituir una herramienta complementaria para explorar la diversidad genética de esta especie.

Variación fenotípica de la langosta espinosa Panulirus argus (Decapoda: Paniluridae) en el Caribe Suroccidental / Phenotypic variation of Panulirus argus (Decapoda: Paniluridae) in Southwest Caribbean

ResumenLa langosta espinosa Panulirus argus es una importante especie pesquera en el Atlántico centro-occidental. Los cambios en el rango de dispersión a través de su ciclo de vida y sus hábitats heterogéneos, sugieren que P. argus exhibe plasticidad fenotípica. Sin embargo, la variación morfométrica de esta especie es desconocida hasta ahora, aún cuando esta información es relevante en estudios evolutivos y en la solución de preguntas de interés pesquero. Por lo tanto, el objetivo de este estudio fue determinar si P. argus exhibe variación fenotípica entre sexos, entre cinco orígenes geográficos y tres condiciones oceanográficas del Caribe suroccidental (archipiélago colombiano de San Andrés, Providencia y Santa Catalina). Un total de 193 adultos de P. argus se analizaron por Morfometría Geométrica usando seis puntos de referencia que delimitan la mitad de la placa esternal. Las diferencias de tamaño entre sexos y orígenes geográficos, se compararon con las pruebas de Kruskal-Wallis y Mann-Whitney. El efecto alométrico se estimó usando Análisis de Regresión Multivariada, el modelo de pendientes alométricas se contrastó con un Análisis Multivariado de Covarianza y las diferencias de conformación de la placa esternal se exploró usando comparaciones no paramétricas de las distancias Euclidianas y árboles del vecino más cercano. Los resultados mostraron que la variación morfométrica de la placa esternal de la langosta espinosa varía de acuerdo al sexo debido a que el dimorfismo sexual fue significativo tanto en el tamaño como en la conformación. En ambos sexos, la conformación de la placa esternal difirió entre escenarios oceanográficos como se evidenció por diferencias significativas entre distancias Euclidianas y su tendencia a agruparse por las secciones norte, centro y sur del archipiélago de San Andrés. Adicionalmente, la variación morfométrica resultante de plasticidad fenotípica a contextos ecológicos variables pueden explicar las diferencias fenotípicas entre poblaciones que son genéticamente similares. Esta información permite definir unidades de manejo, apoya la selección de medidas regulatorias de esta pesquería y complementa los análisis genéticos de la especie en esta región del Caribe.

Abstract:The spiny lobster Panulirus argus is an important fishery species in the Western Central Atlantic. Changes in the dispersion range through its life cycle and heterogeneous habitats, suggest that P. argus exhibit phenotypic plasticity. However, the morphometric variation of this species is unknown so far, although this information is relevant in evolutionary studies as well as to solve questions of fishery interest. Thus, the aim of this study was to determine whether P. argus exhibit phenotypic variation between sexes, among five geographic origins and three oceanographic conditions of Southwest Caribbean (Colombian archipelago San Andrés, Providencia y Santa Catalina). A total of 193 P. argus adults were submitted to geometric morphometrics using six landmarks that delimit one half of the sternal plate. The differences in sternal plate size were compared with KruskalWallis and Mann-Whitney Tests. The allometric effect was estimated using Multivariate Regression Analysis, the model of allometric slopes was tested by Multivariate analysis of covariance and the sternal plate shape differences was explored using non-parametric comparisons of Euclidian distances and Neighbour Joinnig trees. The results showed that the morphometric variation of sternal plate of this spiny lobster varied according to the gender since the sexual size and shape dimorphisms were significant. In both sexes, the sternal plate shape differed among oceanographic scenarios as it was evidenced by significant differences among Euclidian distances, and the tendency to cluster by North, Centre and South sections of San Andrés archipelago. Additionally, the morphometric variation resulting from phenotypic plasticity to variable ecological contexts may explain the phenotypic differences among genetically similar populations. This information permits to define management units, support the selection of regulatory policies of this fishery and complement the genetic analysis of the species in this Caribbean region. Rev. Biol. Trop. 64 (3): 975-990. Epub 2016 September 01.

Molecular identification of Atlantic goliath grouper Epinephelus itajara (Lichtenstein, 1822) (Perciformes: Epinephelidae) and related commercial species applying multiplex PCR

The Atlantic goliath grouper, Epinephelus itajara , is a critically endangered species, threatened by illegal fishing and the destruction of its habitats. A number of other closely related grouper species found in the western Atlantic are also fished intensively. While some countries apply rigorous legislation, illegal harvesting followed by the falsification of fish products, which impedes the correct identification of the species, is a common practice, allowing the catch to be marketed as a different grouper species. In this case, molecular techniques represent an important tool for the monitoring and regulation of fishery practices, and are essential for the forensic identification of a number of different species. In the present study, species-specific primers were developed for the Cytochrome Oxidase subunit I gene, which were applied in a multiplex PCR for the simultaneous identification of nine different species of Epinephelidae: Epinephelus itajara , E. quinquefasciatus , E. morio , Hyporthodus flavolimbatus , H. niveatus , Mycteroperca acutirostris , M. bonaci , M. marginata , and M. microlepis . Multiplex PCR is a rapid, reliable and cost-effective procedure for the identification of commercially-valuable endangered fish species, and may represent a valuable tool for the regulation and sustainable management of fishery resources.(AU)

O mero, Epinephelus itajara , encontra-se criticamente ameaçado, resultado da pesca ilegal e destruição dos habitas. Filogeneticamente relacionadas a este táxon encontram-se garoupas que atualmente são intensamente pescadas no Atlântico Oeste. Apesar de leis mais restritivas aplicadas em alguns países, a captura ilegal com a descaracterização morfológica é uma prática comum que impossibilita a identificação correta da espécie permitindo que seja comercializada como garoupas, badejos ou chernes. A este respeito, técnicas moleculares representam ferramentas importantes para o monitoramento e fiscalização da pesca, provando ser essencial, na identificação forense de diversas espécies. Primers espécie-específicos foram desenvolvidos com base no gene Citocromo Oxidase subunidade I que aplicados em PCR-Multiplex possibilitam a identificação simultânea de nove espécies Epinephelidae: Epinephelus itajara , E. quinquefasciatus , E. morio , Hyporthodus flavolimbatus , H. niveatus , Mycteroperca acutirostris , M. bonaci , M. marginata e M. microlepis . A identificação via PCR multiplex de espécies de peixes ameaçadas e comercialmente importantes é um método rápido, prático, seguro e de baixo custo, que poderá ser útil o controle do uso e manejo sustentável de recursos pesqueiros.(AU)

Impact of minimum catch size on the population viability of Strombus gigas (Mesogastropoda: Strombidae) inQuintana Roo, Mexico / Impacto de la talla mínima de captura en la viabilidad de la población de Strombus gigas (Mesogastropoda: Strombidae) en Quintana Roo, Mexico

The queen conch Strombus gigas represents one of the most important fishery resources of the Caribbean but heavy fishing pressure has led to the depletion of stocks throughout the region, causing the inclusion of this species into CITES Appendix II and IUCN’s Red-List. In Mexico, the queen conch is managed through a minimum fishing size of 200mm shell length and a fishing quota which usually represents 50% of the adult biomass. The objectives of this study were to determine the intrinsic population growth rate of the queen conch population of Xel-Ha, Quintana Roo, Mexico, and to assess the effects of a regulated fishing impact, simulating the extraction of 50% adult biomass on the population density. We used three different minimum size criteria to demonstrate the effects of minimum catch size on the population density and discuss biological implications. Demographic data was obtained through capture-mark-recapture sampling, collecting all animals encountered during three hours, by three divers, at four different sampling sites of the Xel-Ha inlet. The conch population was sampled each month between 2005 and 2006, and bimonthly between 2006 and 2011, tagging a total of 8 292 animals. Shell length and lip thickness were determined for each individual. The average shell length for conch with formed lip in Xel-Ha was 209.39±14.18mm and the median 210mm. Half of the sampled conch with lip ranged between 200mm and 219mm shell length. Assuming that the presence of the lip is an indicator for sexual maturity, it can be concluded that many animals may form their lip at greater shell lengths than 200mm and ought to be considered immature. Estimation of relative adult abundance and densities varied greatly depending on the criteria employed for adult classification. When using a minimum fishing size of 200mm shell length, between 26.2% and up to 54.8% of the population qualified as adults, which represented a simulated fishing impact of almost one third of the population. When conch extraction was simulated using a classification criteria based on lip thickness, it had a much smaller impact on the population density. We concluded that the best management strategy for S. gigas is a minimum fishing size based on a lip thickness, since it has lower impact on the population density, and given that selective fishing pressure based on size may lead to the appearance of small adult individuals with reduced fecundity. Furthermore, based on the reproductive biology and the results of the simulated fishing, we suggest a minimum lip thickness of ≥15mm, which ensures the protection of reproductive stages, reduces the risk of overfishing, leading to non-viable density reduction. Rev. Biol. Trop. 62 (4): 1343-1352. Epub 2014 December 01.

El caracol rosa Strombus gigas representa una de las especies de mayor importancia pesquera en el Caribe, pero la creciente presión pesquera ha llevado al deterioro de las poblaciones en toda la región, llevando a la inclusión de esta especie en el apéndice II de CITES y la lista roja de UICN. En México, el caracol rosa se maneja con una talla mínima de pesca de 200mm longitud de heliconcha y una cuota pesquera que generalmente representa el 50% de la biomasa adulta. Este estudio tuvo como objetivos determinar la tasa intrínseca de crecimiento poblacional del caracol rosa en Xel-Ha, Quintana Roo, México, y evaluar el efecto de un esfuerzo pesquero regulado, simulando la extracción del 50% de la biomasa adulta. Utilizamos tres diferentes criterios de talla mínima para la pesca, para evaluar el efecto de ésta sobre la densidad de la población y discutimos las implicaciones bilógicas asociadas. Los datos demográficos se obtuvieron mediante un muestreo de marcaje-recaptura, recolectando todos los animales presentes, durante tres horas, con tres buzos, en cuatro sitios diferentes de la caleta. En 2005 los muestreos fueron mensuales, y de 2006 a 2011 bimensuales, marcándose un total de 8 292 caracoles. Se obtuvo la longitud de heliconcha y grosor de labio de cada individuo. La talla media de caracoles con labio formado fue de 209.39±14.18mm y la mediana de 210mm. La mitad de los caracoles con un labio formado presentaban tallas de 200mm a 219mm longitud de heliconcha. Suponiendo que la presencia del labio es un indicador de madurez sexual, se puede concluir que muchos animales alcanzan la madurez sexual a tallas mayores de 200mm longitud de heliconcha y deberían ser considerados inmaduros. La estimación de la abundancia relativa y densidad de adultos varía ampliamente según el criterio de clasificación utilizado. Cuando se aplicó una talla mínima de 200mm longitud, el 26.2% a 54.8% de la población calificó como adulta, correspondiendo a un impacto pesquero simulado de casi un tercio de la población. El impacto fue menor simulando la extracción de adultos, utilizando un criterio de clasificación basado en grosor de labio. Se concluyó que la mejor estrategia de manejo para S. gigas es una talla mínima basada en el grosor de labio, ya que esta medida reduce el impacto sobre la densidad poblacional, y por el otro lado disminuye la presión selectiva sobre la talla, lo cual conduce a la aparición de individuos pequeños con fecundidad inferior. Más allá, basado en la biología reproductiva y los resultados de las simulaciones, recomendamos un grosor de labio mínimo de ≥15mm para la pesca, ya que esta medida asegura la protección de las etapas reproductivas y reduce el riesgo de sobrepesca, el cual llevaría a reducciones no viables de la densidad poblacional.

Population biology of the mangrove crab Ucides cordatus (Decapoda: Ucididae) in an estuary from semiarid Northeastern Brazil / Biología poblacional del cangrejo de manglar Ucides cordatus (Decapoda: Ucididae) en un estuario tropical semiárido

The mangrove crab Ucides cordatus is an important resource of estuarine regions along the Brazilian coast. U. cordatus is distributed from Florida, USA, to the coast of Santa Catarina, Brazil. The species plays an important role in processing leaf litter in the mangroves, which optimizes the processes of energy transfer and nutrient cycling, and is considered a keystone species in the ecosystem. Population declines have been reported in different parts of the Brazilian coast. In the present study we evaluated aspects of the population structure, sex ratio and size at morphological sexual maturity. We analyzed 977 specimens collected monthly over 24 months (2010-2012), in a mangrove of the Jaguaribe River, in the municipality of Aracati on the East coast of Ceará state, Northeastern Brazil. The study area has a mild semiarid tropical climate, with mean temperatures between 26 and 28oC. The area is located within the eco-region of the semiarid Northeast coast, where mangroves occur in small areas and estuaries are affected by mesomareal regimes. The population structure was evaluated by the frequency distribution of size classes in each month, and the overall sex ratio was analyzed using the chi-square test. Size at morphological sexual maturity was estimated based on the allometry of the cheliped of the males and the abdomen width of the females, using the program REGRANS. The size-frequency distribution was unimodal in both sexes. The overall sex ratio (M: F) (1:0.6) was significantly different from 1:1. Analysis of the sex ratio by size class showed that the proportion of males increased significantly from size class 55-60mm upward, and this pattern persisted in the larger size classes. In the smaller size classes the sex ratio did not differ from 1:1. The size at morphological sexual maturity was estimated at a carapace width (CW) of 52mm and 45mm for males and females, respectively. Analysis of the population parameters indicated that ...

El cangrejo Ucides cordatus es un importante recurso pesquero de las regiones de estuarios a lo largo de la costa brasileña. Disminuciones de las poblaciones han sido reportadas en diferentes regiones del país. El presente estudio evaluó aspectos de la estructura poblacional, proporción sexual y talla en la madurez sexual. Se analizó un total de 977 ejemplares capturados mensualmente, por 24 meses, en lo manglar del río Jaguaribe, en el municipio de Aracati, en la costa este de Ceará, nordeste del Brasil. El área de estudio tiene un clima semiárido tropical, con temperaturas medias entre los 26 y 28°C. La estructura poblacional fue evaluada para determinar la distribución de frecuencia de clases de talla. Para analizar diferencias significativas respecto a la proporción sexual se aplicó la prueba Chi-quadrado. La talla de la madurez sexual morfológica fue estimada con base en la alometría del propodito del quelípedo de los machos y de la anchura del abdomen de las hembras, utilizando el programa REGRANS. La distribución de frecuencia de talla fue unimodal para los dos sexos. La proporción sexual total (M:H)(1:0.6), se desvió significativamente de la igualdad. El análisis de la proporción entre sexos, relativo a las clases de tallas mostró que la proporción de machos se tornó significativamente más alta desde la clase de 55-60mm de talla, y este se mantuvo en las clases de talla más grande. No obstante, en las clases más pequeñas la proporción entre los sexos no fue distinta de 1:1. La talla de la madurez sexual morfológica fue de 52mm de ancho del caparazón y 45mm para los machos y hembras, respectivamente. Los resultados de los atributos analizados permitieran deducir que la población de U. cordatus en el manglar del río Jaguaribe se encuentran en una situación de estabilidad. Sin embargo, el monitoreo constante de la población es necesario para detectar alteraciones en los atributos de la población que puedan afectar esta situación de estabilidad.

Density and reproduction of the Queen Conch Eustrombus gigas (Mesogastropoda: Strombidae) at Cabo Cruz, Desembarco del Granma National Park, Cuba / Densidad y reproducción de la concha reina Eustrombus gigas (Mesogastropoda: Strombidae) en Cabo Cruz, Parque Nacional Desembarco del Granma, Cuba

The queen conch Eustrombus gigas is an important fisheries resource in the Caribbean region. In Cuba Island the studies about this resource are very scarce and particularly in the Southeastern regions of the country. With the aim to get important fishery information about this gastropod, adult Queen Conch density and frequency of reproductive activity were evaluated in Cabo Cruz, Cuba, during 2009-2010. Data from three seasons were obtained (rainy, dry and cold fronts periods) from three different areas: Farito, Guafe and Laguna. The highest density was observed in cold fronts season (468.5ind./ha) and the lowest occurred during the dry season (268.5ind./ha). The highest density was reported at Laguna (520.4ind./ha) and the lowest at Farito (290.9ind./ha). In total, 158 reproductive events were observed. The highest frequency was reported in rainy season (36%), followed by dry (9%) and cold fronts (5%) seasons. Reproductive behavior (mating and egg laying) was related to temperature and photoperiod. Reproductive activity was observed during the whole year, which suggests the existence of an important Queen Conch reserve in the Southeastern region of Cuba and an apparently self-sufficient population for recruitment. From our results we may conclude that, the population’s sustainable exploitation is viable if the following management measures are observed: functional zoning within the area, rotation of fishing areas and a closed season. We recommend that the Laguna site should be protected as a reproduction zone and banned for fishing activities.

El Eustrombus gigas es un recurso pesquero importante en la región del Caribe. En Cuba, los estudios acerca de este recurso son muy escasos y en la zona Sur-oriental del país son casi nulos. En este trabajo se evalúa la densidad de adultos y frecuencia de la evidencia reproductiva de Eustrombus gigas Linneus 1758 en Cabo Cruz, Cuba, en el periodo 2009-2010. Se obtuvieron datos de tres períodos (lluvias, seca y frentes fríos) en tres zonas: Farito, Guafe y Laguna. La mayor densidad de adultos se observó en frentes fríos (468.5ind./ha) y la menor en seca (268.5ind./ ha). Por zonas, la mayor densidad de adultos se reportó en Laguna (520.4ind./ha) y la menor en Farito (290.9ind./ha). Se observaron 158 evidencias reproductivas. La mayor frecuencia se reportó en lluvias (36%). La temperatura se relacionó con la frecuencia de desove y cantidad de masas de huevos, y el fotoperiodo con la cantidad de agregaciones y frecuencia de cópula. Se observó actividad reproductiva intensa durante todo el año, lo que sugiere una importante reserva de la especie en la región sur-oriental de Cuba y una aparente autosuficiencia de la población para el reclutamiento. La explotación sostenible de la población es viable y Laguna debe ser protegida como zona de reproducción.

Assessment of condition in pejerrey Odontesthes bonariensis (Atheriniformes: Atherinopsidae) populations: which index works best?

The pejerrey Odontesthes bonariensis is the most important target species in temperate freshwater fisheries of Argentina, and assessment of condition has been a regular practice and common diagnostic tool. Most pejerrey fishery studies have used Fulton's (K) index, without testing whether underlying assumptions or requirements were met. We analyzed and contrasted the applicability of K, Kn and Wr indices to assess condition status in several pejerrey populations inhabiting Pampean lakes. Our results showed that whereas Wr and Kn displayed significant condition changes across length at some study lakes, Kn portrayed a small range of variation. We also noted that pejerrey maximum length and size structure strongly varied among populations probably due to the characteristics of trophic niche changes through lifespan, depending on lake limnological characteristics and zooplankton availability. We conclude that the K index should be disregarded in those cases where populations show allometric growth and size ranges strongly vary. In turn, the Kn index appears to be only appropriate for regular within population assessment, being difficult to apply when comparisons between populations are needed and when they exhibit different weight-length relationship slopes. Finally, the Wr index should be strongly preferred if the objective is to perform comparisons between pejerrey populations, particularly when population structure is not well known, stocking has been used for population recovery, lakes are strongly supported by limnological changes, data are limited to only one or few samplings and metaphoetesis is suspected in pejerrey populations.(AU)

O peixe-rei Odontesthes bonariensis é a espécie mais importante na pesca de água doce da região temperada da Argentina, e a avaliação de sua condição corpórea tem sido uma prática normal e uma ferramenta de diagnóstico bastante utilizada. Grande parte dos estudos sobre a pesca do peixe-rei utiliza o índice de Fulton (K), sem testar se seus pressupostos são atendidos. Nós analisamos e comparamos a aplicabilidade dos índices K, Kn e Wr para a avaliação do fator de condição em várias populações de peixe-rei em lagos dos Pampas. Nossos resultados mostram que, enquanto o Wr e o Kn dependeram significativamente do comprimento corporal em alguns lagos, o Kn apresentou uma pequena amplitude de variação. Foi também notado que o comprimento máximo e a estrutura de tamanho variaram fortemente entre populações, provavelmente devido às mudanças ontogenéticas no nicho trófico, dependendo das características limnológicas e da disponibilidade de zooplâncton. Concluímos que o índice K deve ser desconsiderado nos casos em que as populações apresentam variações alométricas marcantes no crescimento e na amplitude de tamanhos. O índice Kn parece ser apropriado apenas para avaliações de uma única população, não sendo apropriado para comparações entre populações quando elas exibem diferentes inclinações na relação peso-comprimento. Finalmente, o índice Wr é recomendado se o objetivo for fazer comparações entre populações de peixe-rei, particularmente quando a estrutura populacional não é bem conhecida, a estocagem tenha sido usada para a recuperação populacional, os lagos apresentam grandes variações limnológicas, os dados se limitam a uma ou poucas amostras e suspeita-se da ocorrência de mudanças ontogenéticas na dieta.(AU)