1000 resultados para Southern cerrado


Relevância:

20.00% 20.00%

Publicador:

Resumo:

As a component of a three-year cooperative effort of the Washington State Department of Ecology and the National Oceanic and Atmospheric Administration, surficial sediment samples from 100 locations in southern Puget Sound were collected in 1999 to determine their relative quality based on measures of toxicity, chemical contamination, and benthic infaunal assemblage structure. The survey encompassed an area of approximately 858 km2, ranging from East and Colvos Passages south to Oakland Bay, and including Hood Canal. Toxic responses were most severe in some of the industrialized waterways of Tacoma’s Commencement Bay. Other industrialized harbors in which sediments induced toxic responses on smaller scales included the Port of Olympia, Oakland Bay at Shelton, Gig Harbor, Port Ludlow, and Port Gamble. Based on the methods selected for this survey, the spatial extent of toxicity for the southern Puget Sound survey area was 0% of the total survey area for amphipod survival, 5.7% for urchin fertilization, 0.2% for microbial bioluminescence, and 5- 38% with the cytochrome P450 HRGS assay. Measurements of trace metals, PAHs, PCBs, chlorinated pesticides, other organic chemicals, and other characteristics of the sediments, indicated that 20 of the 100 samples collected had one or more chemical concentrations that exceeded applicable, effects-based sediment guidelines and/or Washington State standards. Chemical contamination was highest in eight samples collected in or near the industrialized waterways of Commencement Bay. Samples from the Thea Foss and Middle Waterways were primarily contaminated with a mixture of PAHs and trace metals, whereas those from Hylebos Waterway were contaminated with chlorinated organic hydrocarbons. The remaining 12 samples with elevated chemical concentrations primarily had high levels of other chemicals, including bis(2-ethylhexyl) phthalate, benzoic acid, benzyl alcohol, and phenol. The characteristics of benthic infaunal assemblages in south Puget Sound differed considerably among locations and habitat types throughout the study area. In general, many of the small embayments and inlets throughout the study area had infaunal assemblages with relatively low total abundance, taxa richness, evenness, and dominance values, although total abundance values were very high in some cases, typically due to high abundance of one organism such as the polychaete Aphelochaeta sp. N1. The majority of the samples collected from passages, outer embayments, and larger bodies of water tended to have infaunal assemblages with higher total abundance, taxa richness, evenness, and dominance values. Two samples collected in the Port of Olympia near a superfund cleanup site had no living organisms in them. A weight-of-evidence approach used to simultaneously examine all three “sediment quality triad” parameters, identified 11 stations (representing 4.4 km2, 0.5% of the total study area) with sediment toxicity, chemical contamination, and altered benthos (i.e., degraded sediment quality), 36 stations (493.5 km2, 57.5% total study area) with no toxicity or chemical contamination (i.e., high sediment quality), 35 stations (274.1 km2, 32.0% total study area) with one impaired sediment triad parameter (i.e., intermediate/high sediment quality), and 18 stations (85.7km2, 10.0% total study area) with two impaired sediment parameters (i.e., intermediate/degraded quality sediments). Generally, upon comparison, the number of stations with degraded sediments based upon the sediment quality triad of data was slightly greater in the central Puget Sound than in the northern and southern Puget Sound study areas, with the percent of the total study area degraded in each region decreasing from central to north to south (2.8, 1.3 and 0.5%, respectively). Overall, the sediments collected in Puget Sound during the combined 1997-1999 surveys were among the least contaminated relative to other marine bays and estuaries studied by NOAA using equivalent methods. (PDF contains 351 pages)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A multi-disciplinary investigation was conducted in southern Biscayne Bay and Card Sound from 1968 to 1973. The purpose of the investigation was to conduct an integrated study of the ecology of southern Biscayne Bay with special emphasis on the effects of the heated effluent from the Turkey Point fossil fuel power plant, and to predict the impact of additional effluent from the planned conversion of the plant to nuclear fuel. The results of this investigation have been discussed in numerous publications. This report contains the unpublished biology data that resulted from the investigation. (PDF contains 44 pages)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is only the table of contents for a series of technical reports done from 1975-1978. The papers were done on contract for BLM by a number of universities and consulting firms such as Science Applications, Inc., University of Southern California, Scripps Institute of Oceanography, Moss Landing Marine Laboratories, and various campuses of University of California and California State University. (PDF contains 36 pages)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sets and catches of Atlantic menhaden, Brevoortia tyrannus, made in 1985-96 by purse-seine vessels from Virginia and North Carolina were studied by digitizing and analyzing Captain's Daily Fishing Reports (CDFR's), daily logs of fishing activities completed by captains of menhaden vessels. 33,674 CDFR's were processed, representing 125,858 purse-seine sets. On average, the fleet made 10,488 sets annually. Virginia vessels made at least one purse-seine set on 67%-83% of available fishing days between May and December. In most years, five was the median number of sets attempted each fishing day. Mean set duration ranged from 34 to 43 minutes, and median catch per set ranged from 15 to 30 metric tons (t). Spotter aircraft assisted in over 83% of sets overall. Average annual catch in Chesapeake Bay (149,500 t) surpassed all other fishing areas, and accounted for 52% of the fleet's catch. Annual catch from North Carolina waters (49,100 t) ranked a distant second. Fishing activity in ocean waters clustered off the Mid-Atlantic states in June-September, and off North Carolina in November-January. Delaware Bay and the New Jersey coast were important alternate fishing grounds during summer. Across all ocean fishing areas, most sets and catch occurred within 3 mi. of shore, but in Chesapeake Bay about half of all fishing activity occurred farther offshore. In Virginia, areas adjacent to fish factories tended to be heavily fished. Recent regulatory initiatives in various coastal states threaten the Atlantic menhaden fleet's access to traditional nearshore fishing grounds. (PDF file contains 26 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

During June 1974 the California Department of Fish and Game, in cooperation with the Sea Grant program at Moss Landing Marine Laboratories, conducted an exploratory fishing cruise that extended from La Jolla to Santa Cruz and included the Channel Islands, concentrating on inshore waters. The cruise was preliminary to the initiation of a major program of squid research and had six objectives: 1) To gather samples of market squid (Lo1igo opa1escens) for population, growth, aging and food chain studies. 2) To locate potential new fishing grounds. 3) To investigate methods for determining spawning intensity. 4) To gather data on oceanographic parameters of the spawning grounds. 5) To make incidental collections as requested by other investigators. 6) To familiarize Sea Grant personnel with the capabilities of the Department's largest research vessel, ALASKA, with respect to squid. Especially good weather and oceanographic conditions persisting throughout the cruise enabled us to make 66 night1ight stations, 17 midwater trawls and eight bottom trawls. Fishable concentrations of squid were discovered in the areas between Cape San Martin and Partington Point, between Pfeiffer Point and Point Sur, and in Carmel Bay, heretofore unfished. Squid spawning off Santa Cruz Island was observed utilizing an underwater observation chamber aboard the vessel. Mating and feeding behavior were observed in shipboard aquaria. PDF contains 28 pages)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Summer flounder, Paralichthys dentatus, scup, Stenotomus chrysops, and black sea bass, Centropristis striata, cooccur within the Middle Atlantic Bight and off southern New England and are important components of commercial and recreational fisheries. The commercial otter trawl fishery for these species is primarily a winter fishery, whereas the recreational fishery takes place between late spring and autumn. The otter trawl fishery generally targets summer flounder, and less frequently scup, while black sea bass occurs as bycatch. Trips in which all three species were present yielded highest aggregate landings per unit of effort (LPUE) levels and occurred more often than trips landing only one or two species. More than 50% of the trips in the trawl fishery landed at least two of the three species. In contrast, greater than 75% of the recreational landings of each species occurred as a result of trips landing only one species. Differences in the fisheries resulted from the interactions of seasonal changes in species distributions and gear selectivity. (PDF file contains 18 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The authors investigated various life history aspects of 19 rockfish species (Sebastes chlorostictus, S. constellatus, S. dalli, S. elongatus, S. ensifer, S. entomelas, S. flavidus, S. goodei, S. hopkinsi, S. levis, S. melanostomus, S. miniatus, S. ovalis, S. paucispinis, S. rosaceus, S. rosenblatti, S. rufus, s. saxicola, S. semicinctus) from the southern California Bight. These aspects included depth distribution, age-length relationships (of 7 species), length-weight relationships, size at first maturity, spawning season, and fecundity. Growth rates of female S. elongatus, S. hopkinsi, S. ova/is, S. saxicola, and S. semicinctus were higher than male conspecifics. Multiple spawning per season was found in 12 species. Generally, most species spawned between late winter and early summer, though there was some spawning within the genus throughout the year. Spawning season duration ranged from 2 (S. flavidus) to 10 months (S. paucispinis). Spawning seasons tended to start earlier in the year and be of longer duration in the southern California Bight, compared to published data on central California conspecifics. Males matured at a smaller length in 7 of the 17 species studied. Maximum fecundities ranged from 18,000 (S. dalll) to about 2,680,000 (S. levis). (PDF file contains 44 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Menlicirrhus americanus in the northwestern Gulf of Mexico mature at 150-220 mm TL and 12-14 months of age, with males maturing when 10-40 mm smaller than females. Spawning occurs within a broad period from February through November with two discrete peaks which coincide with the periodicity of downcoast alongshore currents (towards Mexico) in spring and fall. This species occurs at depths of less than 5 to 27 m, being most abundant at 5 m or shallower. Young-of-the-year recruit primarily at 5-9 m or shallower and gradually expand their bathymetric range. Age determination by length frequency is feasible in M. americanus but not as simple as in species that spawn in one major period of the year. Only one or two spawned groups normally predominated at anyone time and no more than three co-occurred with few possible exceptions. Observed mean sizes were 138 mm TL at 6 months, and 192 and 272 mm at ages I and II, respectively. Typical maximum size was 296-308 mm and typical maximum age is probably 2-3 years. The largest fISh captured were 392 and 455 mm. Observed sex ratio was 1.2 females to 1 male. Weight, girth, and length-length regressions are presented.(PDF file contains 27 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This literature search identifies a majority of the publications in the period 1880-1980 concerned with the marine gastropod, Thais haemastomafloridmul (Conrad). The southern oyster drill is an economically important oyster predator in the western Atlantic and Gulf of Mexico littoral. Major contributions of each paper to our knowledge of the drill's biology are briefly categorized. Hitherto unpublished research by the author on the snail's biology is documented. (PDF file contains 15 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Expendable bathythermograph data collected by the Ships of Opportunity (SOOP) - Ocean Monitoring Program are analyzed for seasonal and inter-annual variations of the cold pool. Two major SOOP transects within the Middle Atlantic Bight (Southern New England and New York) have been analyzed for the years common to both (1977-81). During the years 1977-81, over 200 transects were occupied, and almost 3,000 XBT's were dropped. Results show that the cold pool is formed with the onset of spring warming and persists until fall overturn, is consistent year to year in both area and weighted average annual temperature, and advects water from the northeast to the southwest. Results also show a 100-d lag in minimum temperature between the Southern New England and New York transects. DitTerences in bathymetry between the two transects and their influence on the cold pool are also discussed. Plots of average (1977-81) bottom temperature for both transects are discussed and show consistent annual weighted mean temperature and areas. Bottom temperature plots for individual years, as well as maximum and minimum bottom temperature plots, are presented as Appendix figures. (PDF file contains 28 pages.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mozambique tilapia (Oreochromis mossambicus) is an indigenous tilapia species in southern Africa, until now the majority of genetic research has been carried out on Asian species of tilapia but this project aims to look at this African species. Those most suited to further development in aquaculture in southern Africa have now been identified. The genetic characterisation of strains has been completed. This information has aided the choice of strains for use in small scale aquaculture and for genetically male tilapia (GMT) production. They will form the basis of future strategies for further genetic improvement, and management of genetic diversity of Mozambique tilapia. The information will also contribute towards responsible management and development of genetic resources, particularly with regard to indigenous species of tilapia. Good progress has been made with the adaptation and implementation of producing the supermale fish required to produce all male offspring, resulting in faster growing populations of tilapia. The presence of the project and its associated activity has been a catalyst for a surge in interest in tilapia culture throughout southern Africa. [PDF contains 183 pages]

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The combination of remotely sensed gappy Sea surface temperature (SST) images with the missing data filling DINEOF (data interpolating empirical orthogonal functions) technique, followed by a principal component analysis of the reconstructed data, has been used to identify the time evolution and the daily scale variability of the wintertime surface signal of the Iberian Poleward Current (IPC), or Navidad, during the 1981-2010 period. An exhaustive comparison with the existing bibliography, and the vertical temperature and salinity profiles related to its extremes over the Bay of Biscay area, show that the obtained time series accurately reflect the IPC-Navidad variability. Once a time series for the evolution of the SST signal of the current over the last decades is well established, this time series is used to propose a physical mechanism in relation to the variability of the IPC-Navidad, involving both atmospheric and oceanic variables. According to the proposed mechanism, an atmospheric circulation anomaly observed in both the 500 hPa and the surface levels generates atmospheric surface level pressure, wind-stress and heat-flux anomalies. In turn, those surface level atmospheric anomalies induce mutually coherent SST and sea level anomalies over the North Atlantic area, and locally, in the Bay of Biscay area. These anomalies, both locally over the Bay of Biscay area and over the North Atlantic, are in agreement with several mechanisms that have separately been related to the variability of the IPC-Navidad, i.e. the south-westerly winds, the joint effect of baroclinicity and relief (JEBAR) effect, the topographic beta effect and a weakened North Atlantic gyre.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

ENGLISH: The map method, the Jones method, the variance-covariance method, and the Skellam method were used to study the migrations of tagged yellowfin tuna released off the southern coast of Mexico in 1960 and 1969. The first three methods are all useful, and each presents information which is complementary to that presented by the others. The Skellam method, as used in this report, is less useful. The movements of the tagged fish released in 1960 appeared to have been strongly directed, but this was probably caused principally by the distribution of the fishing effort. The effort was much more widely distributed in 1970, and the movements of the fish released in 1969 appeared to have been much less directed. The correlation coefficients derived from the variance-covariance method showed that it was not random, however. The small fish released in the Acapulco and 10°N-100°W areas in 1969 migrated to the Manzanillo area near the beginning of February 1970. The medium and large fish released in the same areas in the same year tended to migrate to the southeast throughout the first half of 1970, however. SPANISH: El método de mapas, el de Jones, el de la variancia-covariancia y el de Skellam fueron empleados para estudiar las migraciones del atún aleta amarilla marcado y liberado frente a la costa meridional de México en 1960 y 1969. Los tres primeros métodos son todos útiles, y cada uno presenta información que complementa la presentada por los otros. El método de Skellam, conforme se usa en este informe, es menos útil. Parece que los desplazamientos de los peces marcados y liberados en 1960 hubieran sido fuertemente orientados, pero ésto probablemente fue causado principalmente por la distribución del esfuerzo de pesca. El esfuerzo se distribuyó más extensamente en 1970, y parece que los desplazamientos de los peces liberados en 1969 fueran menos orientados. Los coeficientes de correlación derivados del método variancia-covariancia indicaron, sin embargo, que no eran aleatorios. Los peces pequeños liberados en las áreas de Acapulco y los 10°N-100°W en 1969 migraron al área de Manzanillo a principios de febrero 1970. Los peces medianos y grandes liberados en las mismas áreas en el mismo año tuvieron, sin embargo, la tendencia a desplazarse al sudeste durante el primer semestre de 1970. (PDF contains 64 pages.)