Impact of the California sea lion (Zalophus californianus) on salmon fisheries in Monterey Bay, California

To assess the impact of California sea lions (Zalophus californianus) on salmon fisheries in the Monterey Bay region of California, the percentages of hooked fish taken by sea lions in commercial and recreational salmon fisheries were estimated from 1997 to 1999. Onboard surveys of sea lion interactions with the commercial and recreational f isheries and dockside interviews with fishermen after their return to port were conducted in the ports of Santa Cruz, Moss Landing, and Monterey. Approximately 1745 hours of onboard and dockside surveys were conducted—924 hours in the commercial fishery and 821 hours in the recreational fishery (commercial passenger fishing vessels [CPFVs] and personal skiffs combined). Adult male California sea lions were responsible for 98.4% of the observed depredations of hooked salmon in the commercial and recreational fisheries in Monterey Bay. Mean annual percentages of hooked salmon taken by sea lions ranged from 8.5% to 28.6% in the commercial fishery, 2.2% to 18.36% in the CPFVs, and 4.0% to 17.5% in the personal skiff fishery. Depredation levels in the commercial and recreational salmon fisheries were greatest in 1998—likely a result of the large El Niño Southern Oscillation (ENSO) event that occurred from 1997 to 1998 that reduced natural prey resources. Commercial fishermen lost an estimated $18,031−$60,570 of gear and $225,833−$498,076 worth of salmon as a result of interactions with sea lions. Approximately 1.4−6.2% of the available salmon population was removed from the system as a result of sea lion interactions with the fishery. Assessing the impact of a growing sea lion population on fisheries stocks is difficult, but may be necessary for effective fisheries management.

The Bay Scallop, Argopecten irradians, Massachusetts Through North Carolina: Its Biology and the History of Its Habitats and Fisheries

This article covers the biology and the history of the bay scallop habitats and fishery from Massachusetts to North Carolina. The scallop species that ranges from Massachusetts to New York is Argopecten irradians irradians. In New Jersey, this species grades into A. i. concentricus, which then ranges from Maryland though North Carolina. Bay scallops inhabit broad, shallow bays usually containing eelgrass meadows, an important component in their habitat. Eelgrass appears to be a factor in the production of scallop larvae and also the protection of juveniles, especially, from predation. Bay scallops spawn during the warm months and live for 18–30 months. Only two generations of scallops are present at any time. The abundances of each vary widely among bays and years. Scallops were harvested along with other mollusks on a small scale by Native Americans. During most of the 1800’s, people of European descent gathered them at wading depths or from beaches where storms had washed them ashore. Scallop shells were also and continue to be commonly used in ornaments. Some fishing for bay scallops began in the 1850’s and 1860’s, when the A-frame dredge became available and markets were being developed for the large, white, tasty scallop adductor muscles, and by the 1870’s commercial-scale fishing was underway. This has always been a cold-season fishery: scallops achieve full size by late fall, and the eyes or hearts (adductor muscles) remain preserved in the cold weather while enroute by trains and trucks to city markets. The first boats used were sailing catboats and sloops in New England and New York. To a lesser extent, scallops probably were also harvested by using push nets, picking them up with scoop nets, and anchor-roading. In the 1910’s and 1920’s, the sails on catboats were replaced with gasoline engines. By the mid 1940’s, outboard motors became more available and with them the numbers of fishermen increased. The increases consisted of parttimers who took leaves of 2–4 weeks from their regular jobs to earn extra money. In the years when scallops were abundant on local beds, the fishery employed as many as 10–50% of the towns’ workforces for a month or two. As scallops are a higher-priced commodity, the fishery could bring a substantial amount of money into the local economies. Massachusetts was the leading state in scallop landings. In the early 1980’s, its annual landings averaged about 190,000 bu/yr, while New York and North Carolina each landed about 45,000 bu/yr. Landings in the other states in earlier years were much smaller than in these three states. Bay scallop landings from Massachusetts to New York have fallen sharply since 1985, when a picoplankton, termed “brown tide,” bloomed densely and killed most scallops as well as extensive meadows of eelgrass. The landings have remained low, large meadows of eelgrass have declined in size, apparently the species of phytoplankton the scallops use as food has changed in composition and in seasonal abundance, and the abundances of predators have increased. The North Carolina landings have fallen since cownose rays, Rhinoptera bonsais, became abundant and consumed most scallops every year before the fishermen could harvest them. The only areas where the scallop fishery remains consistently viable, though smaller by 60–70%, are Martha’s Vineyard, Nantucket, Mass., and inside the coastal inlets in southwestern Long Island, N.Y.

Declining Rockfish Lengths in the Monterey Bay, California, Recreational Fishery, 1959–94

California’s Monterey Bay area is an important center of recreational fishing for rockfish of various Sebastes species. The species composition of commercial passenger fishing vessel catches from 1959 to 1994 varied with changes in fishing location and depth. The shift from shallow nearshore locations to deeper offshore locations in the late 1970’s and 1980’s changed the emphasis from the blue rockfish, S. mystinus, of shallow waters to the deeper, commercially fished chilipepper, S. goodei, and bocaccio, S. paucispinis. The mean size of rockfish in the catch increased as the latter species were targeted at greater depths but then declined as stocks of older fish disappeared by the mid 1980’s. During 1960–94 the mean size of all ten leading species in the recreational catch declined. The declines ranged from 1% for canary rockfish, S. pinniger, to 27% for chilipepper. The sizes of the deeper living species declined more than those of shallower species. The low frequency of strong recruitment events and increase in fishing mortality and natural mortality appear to have contributed to the declining mean size. The scarcity of older fish, observed as a drop in mean size to below the size of maturity for 50% of females, leads to concern for future recruitment of the larger species, especially bocaccio, chilipepper, yellowtail rockfish, S. flavidus, and canary rockfish.

Species Trends in Sport Fisheries, Monterey Bay, Calif., 1959-86

Three surveys spanning 28 years were examined for changes in species caught by recreational fishermen from small boats (skiffs) and commercial passenger fishing vessels (CPFV's) in California's Monterey Bay region. As fishing effort increased, the catch of certain nearshore species of rockfish, Sebastes spp., declined. CPFV fishing was conducted farther from port and in deeper water to compensate for declining abundance while most skiffs remained in traditional areas close to port. The trend toward deeper water CPFV fishing has been interrupted only temporarily by increased availability of nearshore species. Life history characteristics of rockfish including residential behavior, variable recruitment, and natural longevity contribute to a vulnerability to localized overfishing for several species.

History of the Fisheries of Raritan Bay, New York and New Jersey

Raritan Bay is the body of water bounded by New York and New Jersey and lying immediately south of New York City (Fig. 1). It has close proximity to the most concentrated urban and industrial area in the United States. Its history has been one of extensive multiple use by the surrounding human population. Dating from the precolonial and colonial periods, people have employed many types of gear to catch and gather its once abundant fishes and shellfishes. Its beaches were once popular for sun bathing and swimming, but after the 1940's they were essentially abandoned because the water became too polluted. Another large use has been for pleasure boating and the transit and dockage of merchant, passenger, and military vessels. Channels and basins were dug in the bay, bulkheads and jetties were constructed along its shores, and it was a donor source of sand and gravel for construction projects. It has also been a receptor for large quantities of domestic and industrial wastes and, mainly for this reason, it is one ofthe most deteriorated estuaries in the United States.

Os usos e sentidos do metilfenidato: experiências entre o tratamento e o aprimoramento da atenção.

O cloridrato de metilfenidato é um estimulante moderado do sistema nervoso central com propriedades semelhantes à anfetamina, indicado principalmente para tratar o Transtorno do Déficit de Atenção e Hiperatividade (TDAH). Segundo relatórios da ONU, sua produção mundial cresceu em torno de 357% entre os anos de 1996 e 2012 enquanto que sua comercialização no Brasil, nesse mesmo período, passou de 9 Kg para 578 Kg, o que significou um aumento de aproximadamente 6.322%. A ampliação no consumo se justifica pela expansão da categoria diagnóstica de TDAH, visto que, a desordem transitória que atingia um número menor de crianças foi transformada em um quadro psiquiátrico incluindo um maior número de sinais e sintomas, persistindo durante a adolescência e toda a vida adulta. Outro possível motivo para o crescimento na comercialização do fármaco é o uso para aprimoramento cognitivo, ou seja, a utilização do metilfenidato por pessoas sem o citado diagnóstico, mas com a finalidade de melhorar o desempenho nos estudos e no trabalho. Assim, buscando entender os usos e sentidos associados ao consumo do remédio, fizemos uma pesquisa de campo de cunho qualitativo e exploratório. Foram realizadas dezesseis entrevistas semiestruturadas com usuários do medicamento. Participaram da investigação onze homens e cinco mulheres, entre 23 e 48 anos. A análise de dados mostrou que todos os entrevistados, independentemente de terem ou não o diagnóstico de TDAH, se reconheciam com dificuldades de atenção, que poderia ser constitucional ou passageiro. Mas, para a maioria dos entrevistados, a procura pelo remédio só ocorreu quando essa característica virou um problema, atrapalhando a preparação para uma importante etapa na vida profissional, como uma prova para concurso público ou residência. Também foi percebido que o relato dos amigos sobre os benefícios do remédio e a experiência pessoal do primeiro comprimido de metilfenidato foi fundamental para que a muitos usuários investigados buscassem a prescrição médica. Ou seja, a maior parte dos entrevistados da pesquisa iniciou a ingestão quando seus amigos lhes contaram sobre os benefícios do remédio para superar os problemas na concentração que atrapalhavam o alcance de uma importante meta profissional. Os participantes da pesquisa apontaram que o consumo do fármaco teria contribuído para melhorar o rendimento nos estudos, já que o estimulante teria aumentado a disposição, a concentração, a memória e a eficiência do desempenho cognitivo. Porém, não foi possível identificar o quanto os efeitos positivos podiam ser o resultado de uma sugestão psicológica, questão levantada por alguns usuários. A análise qualitativa dos dados também revelou que o uso do estimulante ora era vivido como um tratamento para TDAH, ora como aprimoramento cognitivo. Tal ambiguidade parece ser o reflexo de o discurso médico ser o principal meio para justificar o uso do remédio, sem precisar questionar aspectos emocionais, sociais e/ou éticos para alcançar uma melhor performance cognitiva. Assim, entendemos que o presente estudo é uma importante contribuição no campo da Saúde Coletiva por ampliar o conhecimento sobre os usos e sentidos que os seus usuários depositam no estimulante.

Os usos e sentidos do metilfenidato: experiências entre o tratamento e o aprimoramento da atenção.

O cloridrato de metilfenidato é um estimulante moderado do sistema nervoso central com propriedades semelhantes à anfetamina, indicado principalmente para tratar o Transtorno do Déficit de Atenção e Hiperatividade (TDAH). Segundo relatórios da ONU, sua produção mundial cresceu em torno de 357% entre os anos de 1996 e 2012 enquanto que sua comercialização no Brasil, nesse mesmo período, passou de 9 Kg para 578 Kg, o que significou um aumento de aproximadamente 6.322%. A ampliação no consumo se justifica pela expansão da categoria diagnóstica de TDAH, visto que, a desordem transitória que atingia um número menor de crianças foi transformada em um quadro psiquiátrico incluindo um maior número de sinais e sintomas, persistindo durante a adolescência e toda a vida adulta. Outro possível motivo para o crescimento na comercialização do fármaco é o uso para aprimoramento cognitivo, ou seja, a utilização do metilfenidato por pessoas sem o citado diagnóstico, mas com a finalidade de melhorar o desempenho nos estudos e no trabalho. Assim, buscando entender os usos e sentidos associados ao consumo do remédio, fizemos uma pesquisa de campo de cunho qualitativo e exploratório. Foram realizadas dezesseis entrevistas semiestruturadas com usuários do medicamento. Participaram da investigação onze homens e cinco mulheres, entre 23 e 48 anos. A análise de dados mostrou que todos os entrevistados, independentemente de terem ou não o diagnóstico de TDAH, se reconheciam com dificuldades de atenção, que poderia ser constitucional ou passageiro. Mas, para a maioria dos entrevistados, a procura pelo remédio só ocorreu quando essa característica virou um problema, atrapalhando a preparação para uma importante etapa na vida profissional, como uma prova para concurso público ou residência. Também foi percebido que o relato dos amigos sobre os benefícios do remédio e a experiência pessoal do primeiro comprimido de metilfenidato foi fundamental para que a muitos usuários investigados buscassem a prescrição médica. Ou seja, a maior parte dos entrevistados da pesquisa iniciou a ingestão quando seus amigos lhes contaram sobre os benefícios do remédio para superar os problemas na concentração que atrapalhavam o alcance de uma importante meta profissional. Os participantes da pesquisa apontaram que o consumo do fármaco teria contribuído para melhorar o rendimento nos estudos, já que o estimulante teria aumentado a disposição, a concentração, a memória e a eficiência do desempenho cognitivo. Porém, não foi possível identificar o quanto os efeitos positivos podiam ser o resultado de uma sugestão psicológica, questão levantada por alguns usuários. A análise qualitativa dos dados também revelou que o uso do estimulante ora era vivido como um tratamento para TDAH, ora como aprimoramento cognitivo. Tal ambiguidade parece ser o reflexo de o discurso médico ser o principal meio para justificar o uso do remédio, sem precisar questionar aspectos emocionais, sociais e/ou éticos para alcançar uma melhor performance cognitiva. Assim, entendemos que o presente estudo é uma importante contribuição no campo da Saúde Coletiva por ampliar o conhecimento sobre os usos e sentidos que os seus usuários depositam no estimulante.

Modelagem do comportamento dinâmico e análise de fadiga de pontes rodoviárias mistas (aço-concreto).

Considerando-se os diversos carregamentos que solicitam a estrutura de uma ponte rodoviária, ao longo de sua vida útil, alguns possuem um comportamento essencialmente dinâmico, ou seja, variam com o tempo, diferentemente do que é considerado na prática corrente de projeto desse tipo de obra de arte. Em geral, os projetistas desse tipo de estrutura têm tratado carregamentos como o de vento, tráfego de veículos e de pedestres como ações de natureza estática, ignorando seu perfil cíclico. Tal consideração, em diversas situações de projeto, tende a minorar os efeitos das ações dinâmicas sobre o sistema estrutural. Além disso, estruturas submetidas a solicitações cíclicas, sob uma carga inferior à caga máxima suportada pelo material, estão sujeitas ao fenômeno da fadiga. A consideração adequada de todos estes aspectos mostra-se fundamentalmente importante para correta avaliação dos níveis de esforços solicitantes do sistema estrutural e, bem como, para a identificação de fenômenos importantes como o da fadiga que pode vir a provocar, por exemplo, a ruptura de componentes estruturais sem aviso prévio ou motivo aparente. Para tal, nesta dissertação as técnicas para a contagem de ciclos de tensão e a aplicação das regras de dano acumulado foram analisadas através de curvas do tipo S-N, associadas a diversas normas de projeto. A ponte rodoviária mista (aço-concreto) investigada neste estudo é constituída por seis vigas de aço longitudinais com enrijecedores transversais, oito transversinas e por um tabuleiro de concreto armado. O modelo numérico-computacional, desenvolvido para a análise dinâmica da ponte, foi elaborado com base em técnicas usuais de discretização através do método dos elementos finitos. As mesas e almas das vigas, assim como os enrijecedores , foram modelados por elementos de casca e laje de concreto armado, por elementos sólidos. O carregamento dinâmico avaliado no presente estudo diz respeito ao tráfego de veículos, cuja representação se dá a partir de sistemas "massa-mola-amortecedor". Os comboios formados são adotados como sendo semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As conclusões da presente investigação versam acerca da vida útil de serviço dos elementos estruturais de pontes mistas (aço-concreto).

Landing gear for a 'silent' aircraft

The Silent Aircraft Initiative aims to provide a conceptual design for a large passenger aircraft whose noise would be imperceptible above the background level outside an urban airfield. Landing gear noise presents a significant challenge to such an aircraft. 1/10th scale models have been examined with the aim of establishing a lower noise limit for large aircraft landing gear. Additionally, the landing gear has been included in an integrated design concept for the 'Silent' Aircraft. This work demonstrates the capabilities of the closed-section Markham wind tunnel and the installed phased microphone arrays for aerodynamic and acoustic measurements. Interpretation of acoustic data has been enhanced by use of the CLEAN algorithm to quantify noise levels in a repeatable way and to eliminate side lobes which result from the microphone array geometry. Results suggest that highly simplified landing gears containing only the main struts offer a 12dBA reduction from modern gear noise. Noise treatment of simplified landing gear with fairings offers a further reduction which appears to be limited by noise from the lower parts of the wheels. The importance of fine details and surface discontinuities for low noise design are also underlined.

Analyzing and mapping fish assemblages off central California, USA

This study describes fish assemblages and their spatial patterns off the coast of California from Point Arena to Point Sal, by combining the results of the multivariate analyses of several fisheries datasets with a geographic information system. In order to provide comprehensive spatial coverage for the areas of inshore, continental shelf, and continental slope, three fisheries datasets were analyzed: 1) Inshore: the California Department of Fish and Game dataset of fishery-dependent commercial passenger fishing vessel trips that targeted rockfish; 2) Continental Shelf: the National Marine Fisheries Service (NMFS) fishery-independent bottom trawls; and 3) Continental Slope: the NMFS fishery-independent bottom trawls on the continental slope. One-hundred seven species were analyzed. These species represented those captured in at least 5% of the fishing trips or trawls in at least one of the three data sets. We analyzed each of the three datasets separately, and the three sets of results were combined to define 28 species assemblages and 23 site groups. A species assemblage consisted of species caught together, whereas a site group consisted of fishing trips or trawl locations that tended to have the same species assemblages. At the scale of these datasets, 97% of all site groups were significantly segregated by depth.

A three-dimensional tunnel model for calculation of train-induced ground vibration

The frequency range of interest for ground vibration from underground urban railways is approximately 20 to 100 Hz. For typical soils, the wavelengths of ground vibration in this frequency range are of the order of the spacing of train axles, the tunnel diameter and the distance from the tunnel to nearby building foundations. For accurate modelling, the interactions between these entities therefore have to be taken into account. This paper describes an analytical three-dimensional model for the dynamics of a deep underground railway tunnel of circular cross-section. The tunnel is conceptualised as an infinitely long, thin cylindrical shell surrounded by soil of infinite radial extent. The soil is modelled by means of the wave equations for an elastic continuum. The coupled problem is solved in the frequency domain by Fourier decomposition into ring modes circumferentially and a Fourier transform into the wavenumber domain longitudinally. Numerical results for the tunnel and soil responses due to a normal point load applied to the tunnel invert are presented. The tunnel model is suitable for use in combination with track models to calculate the ground vibration due to excitation by running trains and to evaluate different track configurations. © 2006 Elsevier Ltd. All rights reserved.

A novel measurement of dynamic friction

A tribometer, based on a pin-on-disc machine, uses a PZT drive to produce small sinusoidal fluctuations of sliding speed. The frequency and amplitude of these fluctuations can be controlled, and the dynamic response measured. Preliminary test results show that the dynamic friction variation is influenced by the contact materials, normal force, oscillation frequency and steady sliding speed. The variation of friction force amplitude and phase with frequency gives clues about the underlying state variables determining the friction. Modelling studies illustrate the expected behaviour for idealized friction laws governed by, for example, sliding speed, contact temperature, and "rate-state" laws. © 2008 SAE International.

Investigations on long distance transportation of fish 1. Transportation of frozen fish from Cochin to Calcutta

Oil Sardine (Sardinella longiceps), mackerel (Rastrelliger kanagurta), cat fish (Arius sp.), threadfin bream (Nemipterus japonicus) and ribbon fish (Trichurus sp.) were frozen in glazed/unglazed blocks, packed in expanded polystyrene (EPS) insulated plywood boxes with and without additional ice and despatched in uninsulated parcel vans of trains from Cochin to Calcutta. The consignments reached the destination in excellent condition and were readily disposed off.

Improving Pothole Recognition through Vision Tracking for Automated Pavement Assessment

Pavement condition assessment is essential when developing road network maintenance programs. In practice, pavement sensing is to a large extent automated when regarding highway networks. Municipal roads, however, are predominantly surveyed manually due to the limited amount of expensive inspection vehicles. As part of a research project that proposes an omnipresent passenger vehicle network for comprehensive and cheap condition surveying of municipal road networks this paper deals with pothole recognition. Existing methods either rely on expensive and high-maintenance range sensors, or make use of acceleration data, which can only provide preliminary and rough condition surveys. In our previous work we created a pothole detection method for pavement images. In this paper we present an improved recognition method for pavement videos that incrementally updates the texture signature for intact pavement regions and uses vision tracking to track detected potholes. The method is tested and results demonstrate its reasonable efficiency.

Conceptual design for a laminar-flying-wing aircraft

The present study details the conceptual design for a 220-passenger laminar-flying-wing aircraft, utilising distributed suction, with a cruise Mach number of 0.67, over a range of 9000 km. The estimated fuel burn is 13.9 g/pax.km, demonstrating substantial gains relative to current, conventional, passenger aircraft. For comparison, a conventional aircraft with a high-mounted, unswept, wing is designed for the same mission specification, and is shown to have a fuel burn of 15 g/pax.km. Despite significant aerodynamic efficiency gains, the fuel burn of the laminar flying wing is only marginally better as it suffers from a poor cruise engine efficiency and is much heavier. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.