Movement patterns of winter flounder (Pseudopleuronectes americanus) in the southern Gulf of Maine: observations with the use of passive acoustic telemetry

Despite its recreational and commercial importance, the movement patterns and spawning habitats of winter flounder (Pseudopleuronectes americanus) in the Gulf of Maine are poorly understood. To address these uncertainties, 72 adult winter flounder (27–48 cm) were fitted with acoustic transmitters and tracked by passive telemetry in the southern Gulf of Maine between 2007 and 2009. Two sympatric contingents of adult winter flounder were observed, which exhibited divergent spawning migrations. One contingent remained in coastal waters during the spawning season, while a smaller contingent of winter flounder was observed migrating to estuarine habitats. Estuarine residence times were highly variable, and ranged from 2 to 91 days (mean=28 days). Flounder were nearly absent from the estuary during the fall and winter months and were most abundant in the estuary from late spring to early summer. The observed seasonal movements appeared to be strongly related to water temperature. This is the first study to investigate the seasonal distribution, migration, and spawning behavior of adult winter flounder in the Gulf of Maine by using passive acoustic telemetry. This approach offered valuable insight into the life history of this species in nearshore and estuarine habitats and improved the information available for the conservation and management of this species.

Dividing population genetic distance data with the software Partitioning Optimization with Restricted Growth Strings (PORGS): an application for Chinook salmon (Oncorhynchus tshawytscha), Vancouver Island, British Columbia

A new method of finding the optimal group membership and number of groupings to partition population genetic distance data is presented. The software program Partitioning Optimization with Restricted Growth Strings (PORGS), visits all possible set partitions and deems acceptable partitions to be those that reduce mean intracluster distance. The optimal number of groups is determined with the gap statistic which compares PORGS results with a reference distribution. The PORGS method was validated by a simulated data set with a known distribution. For efficiency, where values of n were larger, restricted growth strings (RGS) were used to bipartition populations during a nested search (bi-PORGS). Bi-PORGS was applied to a set of genetic data from 18 Chinook salmon (Oncorhynchus tshawytscha) populations from the west coast of Vancouver Island. The optimal grouping of these populations corresponded to four geographic locations: 1) Quatsino Sound, 2) Nootka Sound, 3) Clayoquot +Barkley sounds, and 4) southwest Vancouver Island. However, assignment of populations to groups did not strictly reflect the geographical divisions; fish of Barkley Sound origin that had strayed into the Gold River and close genetic similarity between transferred and donor populations meant groupings crossed geographic boundaries. Overall, stock structure determined by this partitioning method was similar to that determined by the unweighted pair-group method with arithmetic averages (UPGMA), an agglomerative clustering algorithm.

O jogo e os jogos: o jogo da leitura, o jogo de xadrez e a sanidade mental em A defesa Lujin, de Vladimir Nabokov

No romance A defesa Lujin, de Vladimir Nabokov, publicado em russo em 1930, o texto procura levar o leitor a adotar processos mentais similares ao de um jogador de xadrez e de um esquizofrênico, características do personagem-título do romance. Delineiam-se as expectativas e circunstâncias de um ser de papel que se vê jogando um xadrez em que também é peça e traçam-se paralelos com as expectativas e circunstâncias do leitor perante esse texto literário. O prefácio de Nabokov à edição em inglês de 1964 é tomado como indício de um leitor e um autor implícitos que ele procura moldar. Para análise dos elementos textuais e níveis de abstração mental envolvidos, recorre-se à estética da recepção de Wolfgang Iser e a diversas ideias do psiquiatra e etnólogo Gregory Bateson, entre elas o conceito de duplo vínculo, com atenção às distinções entre mapa/território e play/game. Um duplo duplo vínculo é perpetrado na interação leitor-texto: 1) o leitor é convidado a sentir empatia pela situação do personagem Lujin e a considerá-lo lúcido e louco ao mesmo tempo; e 2) o leitor é colocado como uma instância pseudo-transcendental incapaz de comunicação com a instância inferior (Lujin), gerando uma angústia diretamente relacionável ao seu envolvimento com a ficção, replicando de certa forma a loucura de Lujin. A sinestesia do personagem Lujin é identificada como um dos elementos do texto capaz de recriar a experiência de jogar xadrez até para quem não aprecia o jogo. Analisa-se a conexão entre a esquizofrenia ficcional do personagem Lujin e a visão batesoniana do alcoolismo

Seasonal marine growth of Bristol Bay sockeye salmon (Oncorhynchus nerka) in relation to competition with Asian pink salmon (O. gorbuscha) and the 1977 ocean regime shift

Recent research demonstrated significantly lower growth and survival of Bristol Bay sockeye salmon (Oncorhynchus nerka) during odd-numbered years of their second or third years at sea (1975, 1977, etc.), a trend that was opposite that of Asian pink salmon (O. gorbuscha) abundance. Here we evaluated seasonal growth trends of Kvichak and Egegik river sockeye salmon (Bristol Bay stocks) during even- and odd-numbered years at sea by measuring scale circuli increments within each g rowth zone of each major salmon age group between 1955 and 2000. First year scale growth was not significantly different between odd- and even-numbered years, but peak growth of age-2 smolts was significantly higher than age-1. smolts. Total second and third year scale growth of salmon was significantly lower during odd- than during even-numbered years. However, reduced scale growth in odd-numbered years began after peak growth in spring and continued through summer and fall even though most pink salmon had left the high seas by late July (10−18% growth reduction in odd vs. even years). The alternating odd and even year growth pattern was consistent before and after the 1977 ocean reg ime shift. During 1977−2000, when salmon abundance was relatively great, sockeye salmon growth was high during specific seasons compared with that during 1955−1976, that is to say, immediately after entry to Bristol Bay, after peak growth in the first year, during the middle of the second growing season, and during spring of the third season. Growth after the spring peak in the third year at sea was relatively low during 1977−2000. We hypothesize that high consumption rates of prey by pink salmon during spring through mid-July of odd-numbered years, coupled with declining zooplankton biomass during summer and potentially cyclic abundances of squid and other prey, contributed to reduced prey availability and therefore reduced growth of Bristol Bay sockeye salmon during late spring through fall of odd-numbered years.

Effects of current speed and turbidity on stationary light-trap catches of larval and juvenile fishes

Light traps are one of a number of different gears used to sample pelagic larval and juvenile fishes. In contrast to conventional towed nets, light traps primarily collect larger size classes, including settlement-size larvae (Choat et al., 1993; Hickford and Schiel, 1999 ; Hernandez and Shaw, 2003), and, therefore, have become important tools for discerning recruitment dynamics (Sponaugle and Cowen, 1996; Wilson, 2001). The relative ease with which multiple synoptic light trap samples can be taken means that larval distribution patterns can be mapped with greater spatial resolution (Doherty, 1987). Light traps are also useful for sampling shallow or structurally complex habitats where towed nets are ineffective or prohibited (Gregory and Powles, 1985; Brogan, 1994; Hernandez and Shaw, 2003).

Singapore's biomedical science sector development strategy: is it sustainable?

This paper outlines the strategic efforts undertaken by Singapore to establish its national capability in the biomedical science sector, reviews the commercial base as a result of these efforts and compares Singapore's approach to the UK and the US development models, discusses the challenges that Singapore faces and raises some questions on the long term sustainability of the sector.

The Great Whales: History and Status of Six Species Listed as Endangered Under the U.S. Endangered Species Act of 1973

In the history of whaling from prehistoric to modern times, the large whales, sometimes called the “great whales,” were hunted most heavily owing in part to their corresponding value in oil, meat, and baleen. Regional populations of North Atlantic right whales, Eubalaena glacialis glacialis, were already decimated by 1700, and the North Atlantic gray whale, Eschrichtius robustus, was hunted to extinction by the early 1700’s (Mitchell and Mead1).