Life history and production of Capitella capitata (Polychaeta: Capitellidae) in Río de la Plata Estuary (Argentina)

A benthic survey was carried out from November 1998 to December 1999 in the tidal flats of Bahía Samborombón (Río de la Plata estuary, Argentina), in order to study the population structure, reproductive aspects, growth and secondary production of Capitella capitata (Fabricius, 1780). Growth was analyzed using ELEFAN routine, and the secondary production was estimated by Hynes and Coleman's method (1968). C. capitata did not present periods of very important recruitments throughout the year; however, the abundance of smallest size classes was higher during summer and autumn. The summer cohort showed a growth rate (K) of 2.05 and a seasonal growth oscillation (C) of 0.6, pointing out that worms grew very slowly during winter months. The life span of this cohort was 13 months. The autumn cohort showed a lower growth rate (K= 1.5) and its growth was lowest during winter. The life span was 15 months for this cohort. C. capitata in Punta Rasa presented an extended reproductive period, with absence of activity during winter months. The type of eggs and larvae suggest that C. capitata has benthic larval development in the study area, destining its reproductive effort to the production of a low number of eggs, and assuring larvae survival through incubation in brooding tubes. The annual mean biomass in Punta Rasa was 0.117 g m-2 (AFDW), with a mean secondary production of 0.23 g m-2 y-1 and a P/B ratio of 1.96 y-1. The relatively low density, biomass production and P/B ratio of C. capitata in Punta Rasa can be considered as reference values for this species inhabiting undisturbed or moderately disturbed areas.

Seasonal egg production of whitemouth croaker (Micropogonias furnieri) in the Río de la Plata estuary, Argentina-Uruguay

The reproductive biology of the whitemouth croaker (Micropogonias furnieri) inhabiting the estuarine waters of the Río de la Plata (Argentina-Uruguay) was studied by using histological analysis of the ovaries. Samples were collected during the spawning peak and the end of two breeding seasons (November 1995–Feb-ruary 1996 and November 1997–March 1998). Micropogonias furnieri is a multiple spawner with indeterminate annual fecundity. Spawning frequency, determined by using the percentage of females with postovulatory follicles, was about 31% in November 1995 and 25% in February 1996. At these frequencies, a female on average spawned a new batch of eggs every 3–4 days during the spawning season. Batch fecundity was fitted to a power function of length and a linear function of ovary-free female weight. The number of hydrated oocytes decreased at the end of the breeding season, coinciding with an increase of atresia. Annual egg production for a 40-cm-TL female was estimated to be between 3,300,000 and 7,300,000 eggs. In addition to the seasonal decrease in fecundity and spawning activity, a decline in egg size and weight toward the end of the breeding season was also observed.

Niveles de nutrientes y pigmentos fotosintéticos en el Río de la Plata interior (55°-59°W 34°-36°S)

The "Río de la Plata" River is one of the less studied systems of the basin with respect to its biological and ecological aspects. Twenty four and twenty seven surface stations were sample on September 22-23 and November 22-23, 1982, respectively. The section studied is part of the zone called inner "Río de la Plata" River. The discharge was 29.000 m3/s in September and 45.200 m3/s in November. Total phosphorus (PT), total organic nitrogen (NOT), chemical oxygen demad (COT) and total cholrophyll were measured. Dissolved oxygen (DO), turbidity (TURB), pH and electrical conductivity (K20) were also measured at the surface with a HORIBA U7 sensor on November 1982. PT was 72-208 mg/m3 and 66-205 mg/m3 in September and November repectively; the higher values were near the Argentinian coast and the outer zone. NOT was 33-106 µM and 49-117 µM and CHL was 1.4-5.8 mg/m3 and 1.3-9.4 mg/m3. TURB was between 44 and 240 NTU in November; the maximun value were obseved in the central zone. Steep K20 gradients were found near both coast. The reduced organic carbon load into the lower and external part of the "Río de la Plata" River was estimated. (Document contains 40 pages.)

Trabajos de marcación de peces en el Río de la Plata

Sampling sites were located at: 1) a coastal area on Buenos Aires harbour where high concentrations of "sábalo" occur year round and which on account of its importance merits a specific program itself; 2) a coastal fringe from Buenos Aires harbour to Quilmes (34° 10' - 58° 10') and 3) different stations within the inner zone of the river, which were covered through a tagging campaign performed as part of an agreement among INIDEP-Argentina, CARP-Argentina, Uruguay, INAPE-Uruguay. At present (Winter 1989) recaptures from the first seven species have been obtained, with a total recovery of 3.81 o/o the highest percentages corresponding to patí, boga, armado and sábalo. (Document contains 25 pages.)

Channel Islands Deep Water Monitoring Plan Development Workshop Report April 26-27, 2005 University of California, Santa Barbara

In 2003, twelve marine protected areas were established in state waters (0-3 nmi) surrounding the Channel Islands. NOAA is considering extending this network (3-6 nmi) into deeper waters of the Channel Islands National Marine Sanctuary (CINMS). In order for effective long-term management of the deep water reserves to occur, a well-structured monitoring program is required to assess effectiveness. The CINMS and the National Marine Sanctuary Program (NMSP) hosted a 2-day workshop in April 2005 to develop a monitoring plan for the proposed federal marine reserves in that sanctuary. Conducted at the University of California at Santa Barbara, participants included scientists from academic, state, federal, and private research institutions. Workshop participants developed project ideas that could answer priority questions posed by the NMSP. This workshop report will be used to develop a monitoring plan for the reserves. (PDF contains 47 pages.)

Laboratorio de Ictiofisiología de la Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata

Historia del primer Laboratorio de Ictiofisiología de la Argentina. History of the first Laboratory of Icthyophysiology in Argentina.

Moluscos Litorales del Estuario del Río de la Plata - Argentina.

El Río de la Plata es uno de los cuerpos de agua más importantes de América del Sur. En la actualidad este ambiente es utilizado por el hombre con diferentes propósitos (GARIBOGLIO, 1987; DARRIGRAN, 2002): • Con fines económicos y de recreación (pesca, deportiva y comercial; turismo; deportes; etc.). • Como puerto. • Como fuente de captación de agua para consumo humano. • Como receptor de efluentes industriales. • Como cuerpo receptor de efluentes municipales, sin tratamiento previo. Estos distintos usos que el hombre le da a las aguas del Río de la Plata, muchas veces incompatibles entre ellos, producen un impacto en dicho ambiente difícil de evaluar, debido al escaso conocimiento que existe sobre ese ecosistema. El estudio de la comunidad bentónica, como consecuencia de su limitada movilidad y ciclo de vida apropiado en su duración, es un elemento importante para detectar y evaluar las alteraciones provocadas por la acción humana. En nuestro país no existen estudios específicos sobre el bentos litoral del estuario del Río de la Plata. Referidas a ciertas taxocenosis del macrobentos litoral de la costa argentina del Río de la Plata, se encuentran los trabajos de Darrigran y Rioja (1988), Gullo y Darrigran (1991), relacionados a la distribución de la fauna de isópodos talasoides e hirudíneos, respectivamente. En los 90, existen los trabajos de Darrigran (1991 a y b; 1993; 1998/99); Darrigran y López Armengol (1998), sobre moluscos litorales. Sobre la costa uruguaya del estuario, Scarabino, et al. (1975), realizan un estudio sobre las comunidades bentónicas en el sistema litoral del Departamento de Montevideo. Investigaciones sobre la malacofauna del macrobentos del litoral uruguayo del estuario del Río de la Plata, se encuentran en Sprechmann (1978). En la década de los 90, investigadores del Uruguay, a través de un Programa uruguayo-canadiense orientado hacia la sustentabilidad del estuario Río de la Plata (EcoPlata, 1996), tratan al macrobentos litoral en forma monográfica (Masello & Menafra, 1996). En el presente trabajo se consideran los muestreos de la taxocenosis de moluscos realizados en la zona interna y media de la costa argentina del estuario, antes de la introducción del bivalvo invasor o mejillón dorado, Limnoperna fortunei (Dunker, 1857) a dicha costa (Darrigran & Pastorino, 1995). Cuando se introduce una especie, pueden ocurrir diferentes sucesos: que simplemente se adapte al lugar, en relativo equilibrio con la comunidad pre-existente, o cuando la especie introducida presenta ciertas características (alta tasa de crecimiento, alta capacidad reproductiva-adaptativa, gran poder de dispersión, etc.), sumadas a la falta de enemigos naturales (parásitos, depredadores y/o competidores por los recursos), esta especie está capacitada para realizar una ocupación expansiva, rápida y efectiva del territorio. A esta especie se la denomina “invasora”. A partir de los asentamientos de Limnoperna fortunei, se han detectado severos impactos tanto en el ambiente humano (Darrigran, 1995), como en el ambiente natural (Martín & Darrigran, 1994; Darrigran, et. al, 1998). Estos hechos ponen de manifiesto la importancia de conocer la biodiversidad del bentos en general y de la malacofauna y su distribución en particular, antes de la manifestación de este tipo de contaminación por especies (Rappoport, 1990), como así también, ante el continuo impacto que ejercen las grandes ciudades sobre este cuerpo de agua. Los objetivos de la presente contribución son: 1) Establecer la composición y distribución de la malacofauna del litoral argentino del estuario del Río de la Plata, existente hasta 1991, en relación con dos factores: la salinidad y la contaminación ambiental. 2) Proponer una zonación longitudinal del litoral argentino del Río de la Plata, de acuerdo con los resultados obtenidos a partir del primer objetivo. (Text in Spanish. PDF contains 41 pages.)

Paralelo biológico entre el pejerrey de la laguna de Lobos y el del Río de la Plata (zona frente a Cambaceres).

Estudio biológico comparativo de los pejerreyes de la laguna de Lobos y del Río de la Plata, provincia de Buenos Aires, Argentina. (PDF tiene 15 paginas.)

Faunas locales argentinas. I. Lista de los pescados recogidos en los alrededores de La Plata (prov. de Bs. As.), durante el año 1894 y conservados en las colecciones del Museo de La Plata.

Publicación de la lista de materiales depositados en la Colección de la Sección Zoológica del Museo de La Plata y sus localidades. (PDF tiene 13 paginas.)

Eigenmannia trilineata (Teleostomi, Sternopyginae). Nueva especie hallada en el Río de la Plata.

Revisando los gimnótidos del Río de la Plata, se halló una forma afin a Eigenmannia virescens con la que ha sido confundida.

Status and management of the sea cucumber fishery of La Grande Terre, New Caledonia

From October 2006 to May 2008, The WorldFish Center coordinated a ZoNéCo project to provide support to the Southern and Northern Provinces for decisions about how best to manage the sea cucumber fishery around La Grande Terre. We collected data during underwater population surveys, questionnaire-based interviews with fishers and processors, and landing catch surveys. A core aim was to furnish the Provinces with ‘ballpark’ estimates of the abundance and density of commercially important sea cucumbers on 50 lagoon and barrier reefs. Analysis and synthesis of the ecological and sociological data provide the basis for informed recommendations for fisheries management. Counts of trochus and giant clams on the reefs allow us to also describe the general status of those resources. We propose 13 recommendations for management actions and fishery regulations and advocate an adaptive management approach. This multidisciplinary study should serve as a useful template for assessing other fisheries, and we provide a series of generic ‘lessons learnt’ to aid future programmes. (PDF has 140 pages.)

The growth of Sarotherodon (Tilapia) niloticus L. in Opa Reservoir, University of Ife, Ile-Ife, Nigeria

The growth of Sarotherodon (Tilapia) niloticus in Opa reservoir, University of Ife was determined from the fish scales. Compared with the growth in other similar water bodies the growth was comparatively faster in this newly-impounded reservoir

Potential Application of Adsorptive Media to Enhance Phosphorus Uptake in Stormwater Basins and Wetlands at Lake Tahoe : literature review. Report to the University of California Davis Tahoe Research Group

Phosphorus removal by wetlands and basins in Lake Tahoe may be improved through designing these systems to filter storm water through media having higher phosphorus removal capabilities than local parent material. Substrates rich in iron, aluminum and calcium oftentimes have enhanced phosphorus removal. These substrates can be naturally occurring, byproducts of industrial or water treatment processes, or engineered. Phosphorus removal fundamentally occurs through chemical adsorption and/or precipitation and much of the phosphorus can be irreversibly bound. In addition to these standard media, other engineered substrates are available to enhance P removal. One such substrate is locally available in Reno and uses lanthanum coated diatomaceous earth for arsenate removal. This material, which has a high positive surface charge, can also irreversibly remove phosphorus. Physical factors also affect P removal. Specifically, specific surface area and particle shape affect filtration capacity, contact area between water and the surface area, and likelihood of clogging and blinding. A number of substrates have been shown to effectively remove P in case studies. Based upon these studies, promising substrates include WTRs, blast furnace slag, steel furnace slag, OPC, calcite, marble Utelite and other LWAs, zeolite and shale. However, other nonperformance factors such as environmental considerations, application logistics, costs, and potential for cementification narrow the list of possible media for application at Tahoe. Industrial byproducts such as slags risk possible leaching of heavy metals and this potential cannot be easily predicted. Fly ash and other fine particle substrates would be more difficult to apply because they would need to be blended, making them less desirable and more costly to apply than larger diameter media. High transportation costs rule out non-local products. Finally, amorphous calcium products will eventually cementify reducing their effectiveness in filtration systems. Based upon these considerations, bauxite, LWAs and expanded shales/clays, iron-rich sands, activated alumina, marble and dolomite, and natural and lanthanum activated diatomaceous earth are the products most likely to be tested for application at Tahoe. These materials are typically iron, calcium or aluminum based; many have a high specific surface area; and all have low transportation costs. (PDF contains 21 pages)