Resumo O objetivo deste trabalho foi descrever e analisar uma experiência de pesquisa e extensão com os trabalhadores da Intergremial Marítima do Uruguai, que questionavam a sustentabilidade do modelo de exploração da pesca industrial. Técnicas qualitativas e quantitativas foram utilizadas para levantar e analisar informações e a participação ativa entre os atores sociais (pesquisa participativa). Considerando o complexo pesqueiro produtivo, descrevem-se os vínculos dos sindicatos com a equipe interdisciplinar universitária e, numa perspectiva de extensão, a produção conjunta do conhecimento, a apropriação dele pelos atores e a formulação de propostas alternativas ao modelo de exploração questionado. Os tempos de pesquisa foram conciliados com as urgências dos atores sociais que exigiam a intervenção. A partir da identificação de problemas críticos, o processo de extensão possibilitou o estabelecimento de propostas de mudanças no modelo de exploração e o desafio de construir uma agenda de pesquisa baseada na atividade extensionista.

Resumen Este trabajo describe y analiza una experiencia de investigación y extensión con los trabajadores de la Intergremial Marítima de Uruguay, quienes cuestionaban la sustentabilidad del modelo de explotación pesquero industrial. Se emplearon técnicas cualitativas y cuantitativas de relevamiento y análisis de información y participación activa entre actores sociales (investigación participativa). Considerando el complejo pesquero como productivo, se describen los vínculos de los sindicatos con el equipo universitario interdisciplinario y, desde una perspectiva extensionista, la producción conjunta de conocimiento, la apropiación del mismo por los actores y el planteo de propuestas alternativas al modelo de explotación cuestionado. Se compatibilizaron los tiempos de investigación con las urgencias de los actores sociales que demandaron la intervención. A través de la identificación de problemas críticos, el proceso de extensión permitió establecer propuestas de cambio al modelo de explotación y el desafío de construir agenda de investigación a partir de la actividad de extensión.

Abstract The objective of this work was describing and analyzing a research and extension experience with the workers of the Intergremial Marítima of Uruguay, who questioned the sustainability of the industrial fishing exploitation model. Qualitative and quantitative techniques were used for data collection and analysis, including active participation among social actors (participatory research). Considering the fishing complex as a productive complex, the bonds of the syndicate with the interdisciplinary university team are described from an extensive perspective. This includes, the co–production of knowledge, the appropriation of it by the actors and the alternative proposals to the exploitation model that has been questioned. The research time was reconciled with the urgencies of the social actors who demanded the intervention. From identifying critical issues, the extension process allowed us to establish proposals for changes to the exploitation model and the challenge of building a research agenda from the extension activity.

The present study analyses the seasonal (summer: January, February, March; autumn: April, May, June; winter: July, August, September and spring: October, November, December) and annual (2006, 2007 and 2011) length-weight relationships and condition factors of Micropogonias furnieri and Cynoscion guatucupa from Río de la Plata and the Uruguayan ocean coast from data collected throught monthly landings by the Uruguayan coastal fleet in the Montevideo port (Uruguay). A total of 9,146 individuals of M. furnieri ranging from 15 to 69 cm total length (L T); and 5,285 individuals of C. guatucupa, ranging from 21 to 54 cm L T were analyzed. For both species, the allometry coefficients showed that growth in the majority of seasons were negative (b < 3), except for M. furnieri in spring 2006 (isometric, b = 3) and during summer 2011 (positive, b > 3). For M. furnieri, no significant differences among slopes were found between 2006 and 2007 whereas 2011 showed significant differences compared to 2006 and 2007. For C. guatucupa no significant differences among slopes were found between 2007 and 2011, whereas 2006 showed significant differences with other years. The highest values for the condition factor in M. furnieri were recorded in summer 2006, and during the summer and autumn 2007 and for C. guatucupa in winter 2006 and autumn 2007. Significant seasonal and annual differences for condition factors were found for both species. This work provides the first reference regarding condition factor for both sciaenid species in the study area.

RESUMEN En este trabajo se analizaron las relaciones longitud-peso y el factor de condición de Micropogonias furnieri y Cynoscion guatucupa en diferentes épocas [verano; otoño; invierno, primavera y años (2006, 2007 y 2011)] a partir de muestreos mensuales de desembarques de la flota costera uruguaya que operó en el Río de la Plata y costa oceánica uruguaya. Fueron analizados 9.146 individuos de M. furnieri (entre 15-69 cm de longitud total) y 5.285 individuos de C. guatucupa, (entre 21-54 cm de longitud total). Para ambas especies, el coeficiente de alometría fue negativo (b < 3), excepto para M. furnieri en primavera de 2006 (isométrico, b = 3) y durante verano de 2011 (positivo, b > 3). Para M. furnieri, las pendientes no mostraron diferencias significativas entre el 2006 y 2007, mientras que el 2011 presentó diferencias significativas con ambos años. Para C. guatucupa no se encontraron diferencias significativas entre el 2007 y 2011, pero si cuando ambos años fueron comparados con el 2006. Los mayores valores del factor de condición fueron obtenidos en verano de 2006 y durante el verano y otoño del 2007 para M. furnieri, mientras que para C. guatucupa fueron en invierno 2006 y otoño 2007. Para ambas especies el factor de condición mostró diferencias significativas estacionales y anuales. Este trabajo presenta la primera referencia del factor de condición para estas especies de Sciaenidos en el área de estudio.

ABSTRACT This work analyzed length-mass relationship, growth in length, mass variations and dynamic of yolk sac depletion of Mustelus schmitti embryos, extracted from females catched by the artisanal fishery acting off La Paloma (34°39'S, 54°10'W, Uruguay) during 2006 and 2007. Differences in total length and total mass between sexes were not significant. Embryos showed a negative allometric growth for both years with a slope change near the day 170 of the year, likely to be associated with the depletion of the external yolk sac. Gompertz and Von Bertalanffy curves were adjusted for each year. Parturition date was determined around the day 300 of the year. Yolk depletion followed a logistic dynamic Yt=1/(1+e(-13.749 + 0.072*t)) for 2006 and Yt=1/(1+e(-10.472 + 0.054*t)) for 2007. Embryos showed a mean increase in total dry mass of 5.4g in 187 days which, together with yolk depletion dynamics, indicates additional energetic supply, suggesting that M. schmitti presents limited histotrophy.

RESUMEN Este trabajo analizó las relaciones largo-masa, crecimiento en talla, variaciones en masa y dinámica de consumo del saco vitelino de embriones de Mustelus schmitti extraídos de hembras capturadas por la flota pesquera artesanal del puerto de La Paloma (34°39'S, 54°10'W, Uruguay) durante 2006 y 2007. Las diferencias en largo total y masa total entre sexos no fueron significativas. Los embriones mostraron crecimiento alométrico negativo en ambos años, con un cambio de pendiente cercano al día 170, probablemente asociado con el agotamiento del saco vitelino externo. Se ajustaron curvas de crecimiento de Gompertz y VonBertalanffy para cada año. La fecha de parición se determinó cerca del día 300 del año. El consumo de vitelo siguió una dinámica logística Yt=1/(1+e(-13.749 + 0.072*t)) en 2006 y Yt=1/(1+e(-10.472 + 0.054*t)) en 2007. Los embriones mostraron un aumento promedio de masa seca de 5.4g en 187 días, esto, junto con la dinámica de consumo de vitelo, indicó una provisión adicional de energía, sugiriendo que M. schmitti presenta histotrofía limitada.

We analyzed the stomach contents of 2915 individuals of the whitemouth croaker, Micropogonias furnieri, ranging from 15.6 to 42.0 cm total length, collected from a coastal lagoon in Rocha, Uruguay, during 1997-1999. A total of 56% (n = 1646) of individuals were found with content in their stomachs. Six food items were identified and classified as crustaceans (49%), polychaetes (26%), vegetal debris (15%), molluscs, juvenile fishes, and unidentified contents, the latter three representing less than 5% of the total stomach contents. Fishes displayed a higher proportion of stomachs with food between February and August 1998, simultaneous with a low gonadosomatic index and a decrease in water temperature. Crustaceans were the dominant food item from November 1997 to March 1998 and from November to December 1998 (austral summer), whereas polychaetes were predominant from April to October 1998 and from January to February 1999. Availability of polychaetes and their higher frequency of occurrence in the stomachs before the reproductive period could play an important role in the reproduction of the species. Feeding frequency was correlated with length classes. Smaller fishes (<25 cm) preyed on polychaetes and vegetal debris, whereas larger fishes fed mainly on crustaceans and fishes. The temporal feeding habits of M. furnieri in this coastal lagoon showed selective and opportune utilization of prey items according to annual variability in reproductive status and water temperature.

Fueron analizados los contenidos estomacales de 2915 individuos de la corvina blanca, Micropogonias furnieri, entre 15.6 y 42.0 cm longitud total, recolectados en la laguna costera de Rocha, Uruguay, de 1997 a 1999. El 56% de los individuos (n = 1646) fue encontrado con contenido en sus estómagos. Se identificaron seis ítems alimenticios y se clasificaron como crustáceos (49%), poliquetos (26%), restos vegetales (15%), moluscos, juveniles de peces, y restos no identificados (éstos últimos representaron menos que el 5% del total de contenidos estomacales). Se encontró una gran proporción de estómagos con alimento de febrero a agosto de 1998, en simultaneo con bajos índices gonadosomáticos y un descenso en la temperatura del agua. Los crustáceos predominaron como ítem alimenticio desde noviembre de 1997 hasta marzo de 1998 y de noviembre a diciembre de 1998 (verano austral), mientras que los poliquetos predominaron desde abril hasta octubre de 1998 y en enero y febrero de 1999. La disponibilidad de poliquetos y su mayor frecuencia de ocurrencia en los estómagos antes del periodo reproductivo podría jugar un rol importante en la reproducción de la especie. La frecuencia de alimentación estuvo correlacionada con las clases de talla. Los peces más pequeños (<25 cm) depredaron sobre poliquetos y restos vegetales, mientras que los peces más grandes se alimentaron principalmente de crustáceos y peces. Los hábitos de alimentación temporales de M. furnieri en esta laguna costera mostraron una utilización selectiva y oportuna de los ítems presa a lo largo del año, de acuerdo con el ciclo de reproducción de la especie y la variación de la temperatura.

Neste trabalho foi analisada a variação espacial e temporal da distribuição de comprimento, proporções sexuais e dominância de maduros para Atlantoraja cyclophora e A. castelanui, na plataforma continental uruguaia. Houve diferenças significativas na distribução do comprimento total (TL) entre os sexos, sendo as fêmeas maiores que os machos para ambas espécies. Atlantoraja cyclophora mostrou uma distribuição relativamente uniforme de comprimento entre a prataforma interna e externa. Não houviram grandes variações nas composições do sexo e na dominância de maduros entre as estações do ano, sugerindo que não ha variação temporal. Atlantoraja castelnaui mostrou uma variação significativa na sua distribuição espacial e sazonal. Os indivíduos foram menores na plataforma interna, apontando para a existência de uma zona de juvenis em áreas de até 50 m de profundidade. A tendência para a captura de indivíduos menores no final do ano foi observada. Em todas as estações do ano mais de 50% das fêmeas foram capturadas em um comprimento menor ao tamanho estimado de maturidade observado na literatura, sugerindo que esta espécie é altamente suscetível à explotação.

In this work we analyzed the spatial and seasonal variation of length distribution, sexual proportion and mature dominance for Atlantoraja cyclophora and A. castelnaui, at the Uruguayan continental shelf. There were significant differences in total length (TL) composition between sexes, being females bigger than males for both species. Atlantoraja cyclophora showed a relatively uniform length distribution between inner and outer shelf. There were no major variations in the sex compositions and in the mature dominance between seasons, suggesting no temporal variation. Atlantoraja castelnaui showed a significant variation in its spatial and seasonal distribution. Individuals were smaller in inner shelf, pointing out the existence of juvenile zone in areas up to 50 m depth. A tendency to capture smaller individuals towards the end of the year was observed. In all seasons over 50% of females were caught below the estimated size at maturity, suggesting that this species is highly susceptible to exploitation.

The diet of the South American Tern (Sterna hirundinacea) and its seasonal variation during the 2005 and 2006 non-reproductive seasons in the Uruguayan Atlantic coast was analyzed. Diet was assessed by the analysis of pellets collected in the Rocha lagoon sandbar, a major tern roosting area in Uruguay, aiming to analyze the hypothesis that terns feed mainly on the Argentine Anchovy (Engraulis anchoita) during the wintering period. A total of 844 pellets were collected, 442 in 2005 and 402 in 2006. Diet was composed of fish (88 %), insects (9 %) and crustaceans (3 %). The main fish species consumed was the Argentine Anchovy (77.7 %), followed by Marini's Anchovy (Anchoa marinii) (7.9 %) and the Striped Weakfish (Cynoscion guatucupa) (3.6 %). Insects and crustaceans were the main items in two of the groups of pellets collected during the study period. Despite this temporal variation in the diet, the Argentine Anchovy was the main prey item consumed during both seasons. These results support the hypothesis that South American Terns strongly depend on anchovies as trophic resource.

En este trabajo se analizó la dieta del Gaviotín Sudamericano (Sterna hirundinacea) y su variación estacional durante las temporadas no reproductivas de 2005 y 2006 en la costa atlántica uruguaya. La dieta fue estudiada por medio del análisis de bolos colectados en la barra de la laguna de Rocha, una importante zona de descanso para la especie en Uruguay, con el propósito de analizar la hipótesis de que el gaviotín se alimenta principalmente de Anchoíta Argentina (Engraulis anchoita) durante el período de invernada. Un total de 844 bolos fueron colectados, 442 en 2005 y 402 en 2006. La dieta estuvo compuesta por peces (88 %), insectos (9 %) y crustáceos (3 %). La principal presa consumida fue la Anchoíta Argentina (77.7 %), seguida de la Anchoa (Anchoa marinii) (7.9 %) y la Pescadilla de Red (Cynoscion guatucupa) (3.6 %). Los insectos y los crustáceos fueron el ítem principal en dos de las muestras (grupos de bolos) colectadas durante el período de estudio. A pesar de esta variación temporal en la dieta la Anchoíta Argentina fue la presa principal durante las dos temporadas de estudio. Este resultado apoya la hipótesis planteada de que la anchoíta es el principal recurso alimenticio del Gaviotín Sudamericano.

Foram analisadas as associações dos peixes demersais provenientes de arrastos de prospecção no estuário do Rio de la Plata e sua plataforma interna no período de 1975 a 1995. Os dois primeiros fatores da Análise de Componentes Principais explicaram 48% da variância na distribuição das espécies sendo consistentes com os resultados da análise de agrupamento. Os resultados mostraram a existência de três associações de peixes espacial e temporalmente distintas: uruguaia costeira, estuarina externa e estuarina interna. Essas associações foram consistentes quanto às características ambientais e de composição de espécies. A despeito das mudanças registradas na densidade das espécies ao longo do período analisado, as associações de peixes foram persistentes ao longo do tempo. No presente trabalho foi demonstrado que embora as associações sejam consideradas um sistema aberto, um fluxo recíproco de organismos acontece entre associações adjacentes. Contudo, cada associação apresenta diferentes graus de estabilidade, dependentes da estabilidade física e temporal do habitat, e das interações das espécies nas associações. No entanto, cada associação mostrou alta persistência espacial e temporal, apesar da variabilidade ambiental no sistema analisado. Nesse sentido, e de acordo com a pesca multiespecífica que opera neste sistema, cada associação poderá ser considerada como uma unidade de gestão.

Demersal fish assemblages from trawl surveys in the Rio de la Plata estuary and its inner continental shelf were analyzed from 1975 to 1995. The first two factors of Principal Component Analysis explained 48% of the variance in species distribution, and they are consistent with the results of a cluster analysis. The analysis indicated the existence of three spatially and temporally distinct fish assemblages: internal and external estuarine and inner continental shelf (Uruguayan coastal assemblages). These assemblages were persistent considering the environmental characteristics and their species composition. Despite the changes registered in the species density during the period surveyed, the fish assemblages tend to persist over time. It was demonstrated that the assemblages can be considered as open systems and that there exists a reciprocal flow of organisms between adjacent associations. However, each assemblage showed high spatial and temporal persistence in accordance with the environmental characteristics of the system analyzed. Therefore, and according to the multispecies fisheries operating in the system, each assemblage defined could be considered a unit of management.

This study analyses the seasonal fisheries and sexual proportion of the narrownose smooth-hound Mustelus schmitti from the Uruguayan oceanic coast. The maximum catches took place during the fall. Of a total of 2105 individuals, 1483 were males and 622 females, being females larger than males. Females were dominant at maximum depths of 50 m (inner shelf), whereas males occupied major depths of 50 m (outer shelf). The great proportion of mature females on the inner shelf during spring and summer, and mature males in summer are related to the mating, ovulation and delivery time as previously proposed for this shark in this area. The length in which 50% of the females were retained was below or on the length of sexual maturity of the narrownose smooth-hound, indicating that these are more affected by the fishing activity. Nevertheless, an important fraction of the population that distributes on the inner and outer shelf during the time of parturition, ovulation and mating would be protected in spring and summer by the establishment of fishing bans of the fishes Cynoscion guatucupa and Merluccius hubbsi

Espécimes de Rioraja agassizi foram mensalmente coletados em águas ao largo de Santos, sudeste do Brasil entre as latitudes 23º37'S e 27º40'S, desde março de 2005 até março de 2006. Um total de 278 machos e 1023 fêmeas foi capturado. A amplitude de profundidade de ocorrência foi 10-120 m, estando a espécie ausente em profundidades >120 m. A razão sexual favoreceu as fêmeas. A amplitude completa de comprimentos de R. agassizi esteve representada e oscilou nas fêmeas entre 16.0-59.4 cm comprimento e nos machos entre 13.0-47.2 cm. O tamanho médio das fêmeas foi significativamente maior do que dos machos. A distribuição de freqüência de comprimentos por amostras agrupadas foi assimétrica em ambos os sexos. As curvas da relação comprimento-largura foram sexualmente dimórficas. As fêmeas foram mais largas que os machos em todas as classes de comprimento maiores do que 25 cm. As curvas comprimento-peso total foram significativamente diferentes das curvas comprimento-peso eviscerado em ambos os sexos. As fêmeas foram mais pesadas do que os machos para uma determinada classe de comprimento. O coeficiente angular b foi <3 nos machos (alometría negativa) e nas fêmeas, mas com exceção da primavera, onde a alometría foi positiva (b>3). O fator de condição variou significativamente ao longo do ano em ambos os sexos.

Specimens of Rioraja agassizi were collected monthly off Santos, Southeast Brazil, between latitudes 23º37'S and 27º40'S, from March, 2005 to March, 2006. A total number of 278 males and 1023 females were captured. Observed depth range was 10-120 m, being the species absent above 120 m. Sex ratio significantly favored females. The entire length range of R. agassizi was observed. Females ranged in length from 16.0 to 59.4 cm and males from 13.0 to 47.2 cm. Mean female length was significantly higher than that of males. For grouped length distributions, asymmetry patterns were observed in both sexes. Length-width functions were sexually dimorphic. Males with lengths < 24.5 cm were relatively wider than females. Length-total weight curves were significantly different than length-gutted weight ones, in both sexes. Females were heavier than males for a given TL class. The angular coefficient b was significantly <3 (negative allometry) in the males, and also for the females with exception of spring when b was >3 (positive allometry). The monthly variation of the condition factor showed significant differences in both sexes.

Um total de 4824 Mustelus schmitti foi amostrado. As fêmeas apresentaram comprimento total de 25-93 cm na primavera e 28-90 cm no verão enquanto os machos apresentaram 34-82 e de 28-77 cm, respectivamente. A composição de comprimentos da população mostrou diferenças significativas entre primavera e verão sendo as fêmeas maiores do que os machos. A distribuição de comprimento total não variou significativamente entre cruzeiros. A densidade variou significativamente entre cruzeiros nos machos sendo que a variação não foi expressiva nas fêmeas. No cruzeiro da primavera, ambos os sexos ocorreram em profundidades menores do que 50 m, as fêmeas ocorrendo em toda a área de estudo, as adultas somente acima da latitude 35°30'S. Os machos adultos foram observados em toda a área sendo que os imaturos somente em dois arrastos na Bahia de Samborombón. O cruzeiro de verão mostrou uma distribuição descontínua da espécie ao longo da área de estudo, resultando na segregação espacial em dois grupos, com predominância de fêmeas imaturas em ambos.

A total number of 4824 Mustelus schmitti was sampled. Females ranged from 25 to 93 cm in spring and from 28 to 90 cm in summer. Males ranged from 34 to 82 and from 28 to 77 cm, respectively. Length composition of the population showed significant differences between spring and summer being females larger than males. Total length distribution did not show significant differences between cruises. Males density varied significantly between cruises while for the females no significant variation was observed. In the spring cruise, both sexes occurred at depths lower than 50 m. Females occurred in the whole area with adult occurrence only above 35°30'S. Mature males occurred throughout the area, immature males occurring in two trawls in Samborombón Bay. The summer cruise showed a discontinuous distribution of the species along the study area resulting in spatial segregation in two groups with immature females predominating in both of them.

A total of 293 stomachs of adult flounders, Paralichthys orbignyanus, were analyzed from the catch of artisanal fisheries that operate in Rocha Lagoon, Uruguay. Flounders between 25 and 64 cm total length showed that 119 individuals (40.61%) had content in their stomachs, the silverside Odontesthes argentinensis being the main prey item. Significant variations were observed between size classes. Cannibalism was less than 3% of total prey items and occurred within the 46-56 cm size class. Significant and positive trends were observed between the length of the silverside and the total length of the flounder, but a low percentage of the variability in prey size (<47%) was explained by the predator size. The specialized and selective diet of P. orbignyanus adults is considered to be typical of active piscivore predators and visual fish feeders. The state of prey digestion (in relatively fresh condition or in the beginning of digestion), the moment of catch and the low feeding index could indicate that the species acts as an active predator during the night.

Se analizaron 293 estómagos de lenguados adultos (Paralichthys orbignyanus) de 25 a 64 cm de longitud total (LT), a partir de muestreos ocasionales de capturas de la pesca artesanal que opera en la laguna costera de Rocha, Uruguay. Un total de 119 individuos (40.61%) presentaron contenido estómacal, siendo el pejerrey (Odontesthes argentinensis) su presa principal. Se encontraron variaciones significativas (P < 0.05) en la dieta entre clases de talla. El canibalismo fue menor al 3% del total de las presas y ocurrió en el rango de tallas de 46 a 56 cm. Se observaron tendencias positivas y significativas entre la longitud del pejerrey y la longitud total de los lenguados, pero sólo un porcentaje bajo de la variabilidad en el tamaño de la presa (<47%) fue explicado por el tamaño del predador. La dieta especializada y selectiva de los adultos de P. orbignyanus sugiere que ésta es típica de un predador piscívoro activo que utiliza la visión para capturar sus presas. El estado de digestión de las presas (en condiciones relativamente frescas o en principio de digestión), el momento de la captura y el bajo índice de alimentación podrían estar indicando que la especie actúa como un predador activo durante la noche.

The structure of the population of white croaker (Micropogonias furnieri), a bycatch species of the multi-specific artisanal fishery at the coastal lagoon of Rocha, was analyzed. This species is Uruguay's second fishery resource and it has been declared fully exploited. Few data are available on the artisanal fishery and the biology of this fish, which inhabits the Uruguayan coastal lagoons. The white croakers were obtained from the bycatch of five fisheries that target diverse species in different parts of the lagoon. The five net types studied (mesh sizes 1, 2, 4, 10 and 20 cm) caught different fractions of the structure per size, sex and maturity stage. Both the median and first quartile of the size composition retained by each net size were bigger than the size at first maturity. This work shows the effect of different kinds of artisanal fishery on the structure of the white croaker population and provides basic information for the conservation and management of one of the fishery resources whose habitat forms part of the national park within the MAB/UNESCO Bañados del Este Biosphere Reserve.

Se analizó la estructura de la población de corvina blanca (Micropogonias furnieri) capturada de manera incidental en la pesquería artesanal y multiespecífica de Laguna de Rocha, Uruguay. La especie, que es el segundo recurso pesquero en Uruguay, ha sido declarada plenamente explotada y existen pocos estudios sobre su pesca artesanal y sobre su biología, como pez que habita en las lagunas costeras uruguayas. Las corvinas blancas se obtuvieron como fauna acompañante de cinco pesquerías de distintas especies objetivo que operan en diferentes zonas de la laguna. Los cinco artes de pesca analizados (con apertura de malla de 1, 2, 4, 10 y 20 cm) capturaron distintas fracciones de la estructura por tallas, sexos y estadios de madurez. La mediana y el primer cuartil de la composición de tallas retenidas por cada uno de los artes de pesca fueron mayores que la talla de primera madurez. En este trabajo se muestra el efecto de diferentes modalidades de pesca artesanal sobre la estructura de la población de la corvina blanca y provee información básica que puede utilizarse para la conservación y manejo de uno de los recursos pesqueros cuyo hábitat forma parte de un Parque Nacional dentro de la Reserva de la Biosfera Bañados del Este de la MAB/UNESCO.

The marine areas of Uruguay consist of the Río de la Plata estuary and the adjacent shelf and slope, part of the Subtropical Convergence Ecosystem. In this paper, the main advances in the knowledge of marine life in these areas (the known) are reviewed in order to discuss future lines of research (the unknown). Information has been separately analysed for the plankton, nekton, and benthos in each of 3 areas-the littoral, the shelfs and the "open ocean". Current knowledge of marine life is uneven among the groups and areas. In the case of the plankton, research has concentrated on the near-shore waters and focused on taxonomy and distribution. Little is known about the responses of organisms to environmental variability and about biological processes. The nekton of coastal and estuarine areas is better known, but, with shelf and slope assemblages, research has focused on exploited species. The main unknowns for the nekton are how trophodynamics, reproduction, and recruitment processes are linked to environmental variability and the effect of fisheries on community structure. Littoral benthos, in particular the macroinfauna of sandy beaches, is much better studied and spatial patterns of community distribution have been identified at different scales and in relation to environmental variables. Also, at the population level, there is information about distribution, responses to disturbances, dynamics, and the roles of biotic and abiotic factors in modulating population variability. Information is mainly lacking for the sub-tidal fringe and regarding the macro-ecology of population dynamics, the dispersive abilities of larval phases, and the effects of toxic blooms on suspension feeders. Knowledge of the benthos of estuaries and more so of the shelf and slope environments is rather scarce. For the latter two, faunal inventories are far from complete. Topics identified for future research include taxonomy, macro-scale community structure and its temporal variability in relation to environmental gradients, diverse aspects of population dynamics trophodynamics and the effects of human intervention on ecosystems. The incorporation of both experimental and modelling approaches is considered important for future investigations.

Las aguas uruguayas comprenden el estuario del Río de la Plata y la plataforma y talud contiguos, parte del Ecosistema de Convergencia Subtropical. Esta contribución revisa los principales avances en el conocimiento de la vida marina en esta zona (lo conocido), para discutir futuras líneas de investigación (lo desconocido). Se analiza separadamente la información del plancton, necton y bentos de tres áreas: litoral, plataforma y ``océano profundo''. El conocimiento resulta disparejo entre grupos y entre áreas. En el plancton, la investigación se concentró en el litoral y enfocada hacia aspectos taxonómicos y de distribución, existiendo fuertes deficiencias en el conocimiento de las respuestas de los organismos a la variabilidad ambiental y de procesos biológicos. El necton de áreas estuarinas y costeras es mejor conocido que el de plataforma y talud, donde la investigación ha sido dirigida principalmente a especies explotadas. En este grupo, los principales aspectos desconocidos son los trofodinámicos, los procesos reproductivos y de reclutamiento en función de la variabilidad ambiental, y el efecto de las pesquerías sobre la estructura comunitaria. El bentos litoral, en particular la macroinfauna de playas arenosas, es el componente mejor conocido: se han establecido patrones de distribución comunitaria en diferentes escalas espaciales y en relación a variables ambientales. A nivel poblacional existe información sobre distribución, repuesta a perturbaciones, dinámica, y sobre el papel de factores bióticos y abióticos en la modulación de la variabilidad poblacional. La información faltante se refiere a la franja submareal, así como a aspectos macro ecológicos de dinámica poblacional, dispersión larval y el efecto de las floraciones tóxicas sobre organismos suspensívoros. El bentos de estuarios, y en particular aquél de plataforma y talud, es muy poco conocido; para los últimos los inventarios faunísticos son extremadamente incompletos. Los tópicos identificados para próximas investigaciones incluyen taxonomía, la estructura de las comunidades y su variabilidad temporal en gradientes ambientales, diversos aspectos de dinámica poblacional, trofodinámica y el efecto de la intervención humana en los ecosistemas. Se considera muy importante la incorporación de enfoques experimentales y modelización.