Vertical movement patterns of skipjack tuna (Katsuwonus pelamis) in the eastern equatorial Pacific Ocean, as revealed with archival tags

Thirty-three skipjack tuna (Katsuwonus pelamis) (53−73 cm fork length) were caught and released with implanted archival tags in the eastern equatorial Pacific Ocean during April 2004. Six skipjack tuna were recap-tured, and 9.3 to 10.1 days of depth and temperature data were down-loaded from five recovered tags. The vertical habitat-use distributions indicated that skipjack tuna not associated with floating objects spent 98.6% of their time above the thermocline (depth=44 m) during the night, but spent 37.7% of their time below the thermocline during the day. When not associated with floating objects, skipjack tuna displayed repetitive bounce-diving behavior to depths between 50 and 300 m during the day. The deepest dive recorded was 596 m, where the ambient temperature was 7.7°C. One dive was particularly remarkable because the fish contin-uously swam for 2 hours below the thermocline to a maximum depth of 330 m. During that dive, the ambient temperature reached a low of 10.5°C, and the peritoneal cavity temperature reached a low of 15.9°C. The vertical movements and habitat use of skipjack tuna, revealed in this study, provide a much greater understanding of their ecological niche and catchability by purse-seine fisheries.

Geographical differences in the feeding patterns of red rockfish (Sebastes capensis) along South American coasts

Feeding habits and feeding strategy of red rockfish (Sebastes capensis) were studied from fish captured along most of the range of this species in coastal waters of South America. Stomach contents of 613 individuals, collected during 2003, were analyzed. Fish were obtained from six locations along the Chilean (23°S to 46°S) and Argentinian (43°S) coasts. The main prey items were Mysidacea (75.06% IRI), Osteichthyes (6.29% IRI),and Rhynchocinetes typus (6.03% IRI). Predator sex and size did not significantly affect the diet, but significant differences were found between locations. Four geographical areas, discriminated by prey occurrence and frequencies, were determined: three on the Pacific coast and one on the Atlantic coast. These areas correspond roughly with biogeographic zones described for the Chilean and southern Argentinian coasts. The feeding strategy index (FSI) indicated a specialized feeding strategy for S. capensis for most of its range. However, the FSI does not include the behaviour of a predator, and the FSI must be interpreted carefully for fishes like S. capensis that are passive ambush feeders. The abundance and availability of different prey may explain both the geographic differences in dietary composition and the specialized feeding strategy of S. capensis.

Patterns of genetic variation in the endangered European mink (Mustela lutreola L., 1761)

Background: The European mink (Mustela lutreola, L. 1761) is a critically endangered mustelid, which inhabits several main river drainages in Europe. Here, we assess the genetic variation of existing populations of this species, including new sampling sites and additional molecular markers (newly developed microsatellite loci specific to European mink) as compared to previous studies. Probabilistic analyses were used to examine genetic structure within and between existing populations, and to infer phylogeographic processes and past demography. Results: According to both mitochondrial and nuclear microsatellite markers, Northeastern (Russia, Estonia and Belarus) and Southeastern (Romania) European populations showed the highest intraspecific diversity. In contrast, Western European (France and Spain) populations were the least polymorphic, featuring a unique mitochondrial DNA haplotype. The high differentiation values detected between Eastern and Western European populations could be the result of genetic drift in the latter due to population isolation and reduction. Genetic differences among populations were further supported by Bayesian clustering and two main groups were confirmed (Eastern vs. Western Europe) along with two contained subgroups at a more local scale (Northeastern vs. Southeastern Europe; France vs. Spain). Conclusions: Genetic data and performed analyses support a historical scenario of stable European mink populations, not affected by Quaternary climate oscillations in the Late Pleistocene, and posterior expansion events following river connections in both North-and Southeastern European populations. This suggests an eastern refuge during glacial maxima (as already proposed for boreal and continental species). In contrast, Western Europe was colonised more recently following either natural expansions or putative human introductions. Low levels of genetic diversity observed within each studied population suggest recent bottleneck events and stress the urgent need for conservation measures to counteract the demographic decline experienced by the European mink.

Behavioral ontogeny in larvae and early juveniles of the giant trevally (Caranx ignobilis) (Pisces: Carangidae)

Behavior of young (8−18 mm SL) giant trevally (Caranx ignobilis), a large coral-reef−associated predator, was observed in the laboratory and the ocean. Size was a better predictor of swimming speed and endurance than was age. Critical speed increased with size from 12 to 40 cm/s at 2.7 cm/s for each mm increase in size. Mean scaled critical speed was 19 body lengths/s and was not size related. Swimming speed in the ocean was 4 to 20 cm/s (about half of critical speed) and varied among areas, but within each area, it increased at 2 cm/s for each mm increase in size. Swimming endurance in the laboratory increased from 5 to 40 km at 5 km for each mm increase in size. Vertical distribution changed ontogenetically: larvae swam shallower, but more variably, and then deeper with growth. Two-thirds of individuals swam directionally with no ontogenetic increase in orientation precision. Larvae swam offshore off open coasts, but not in a bay. In situ observations of C. ignobilis feeding, interacting with pelagic animals, and reacting to reefs are reported. Manusc

Spatial and temporal patterns in the bycatch of seabirds in the Argentinian longline fishery

Longline fisheries have grown throughout the world’s oceans for more than 40 years. This type of fisheries has captured high-quality fish (mature individuals rather than unwanted juveniles), has had minimal destructive effects on bottom habitats, and has produced a low bycatch of nontargeted fish (Brothers et al., 1999). Seabirds, however, are hooked accidentally when they swallow or are snagged on the baited hooks set by commercial longline crews (Brothers, 1991; Barnes et al., 1997; Tasker et al., 2000; Belda and Sanchez 2001; Jahncke et al., 2001

Exploring intraspecific life history patterns in sharks

Marine ecosystems compose the major source (85%) of world fisheries production (Garcia and Newton, 1997). Although only a few fish species tend to dominate fishery catches (Jennings et al., 2001), a large diversity of fishes representing varied taxonomic levels, ecological guilds, and life histories is commonly taken. Recently, 66% of global marine resources were determined to be either fully, heavily, or over-exploited (Botsford et al., 1997). Considering the current state of many fisheries, the large diversity of species taken globally, and the general lack of resources to adequately assess many stocks, it has become important to develop shortcuts that may provide methods fisheries scientists can use to determine which stocks are in danger of overexploitation and which recovery plans are appropriate when biological data are limited (Stobutzki et al., 2001).

Patterns of growth, mortality, and size of the tropical damselfish Acanthochromis polyacanthus across the continental shelf of the Great Barrier Reef

Age-based analyses were used to demonstrate consistent differences in growth between populations of Acanthochromis polyacanthus (Pomacentridae) collected at three distance strata across the continental shelf (inner, mid-, and outer shelf) of the central Great Barrier Reef (three reefs per distance stratum). Fish had significantly greater maximum lengths with increasing distance from shore, but fish from all distances reached approximately the same maximum age, indicating that growth is more rapid for fish found on outer-shelf reefs. Only one fish collected from inner-shelf reefs reached >100 mm SL, whereas 38−67% of fish collected from the outer shelf were >100 mm SL. The largest age class of adult-size fish collected from inner and mid-shelf locations comprised 3−4 year-olds, but shifted to 2-year-olds on outer-shelf reefs. Mortality schedules (Z and S) were similar irrespective of shelf position (inner shelf: 0.51 and 60.0%; mid-shelf: 0.48 and 61.8%; outer shelf: 0.43 and 65.1%, respectively). Age validation of captive fish indicated that growth increments are deposited annually, between the end of winter and early spring. The observed cross-shelf patterns in adult sizes and growth were unlikely to be a result of genetic differences between sample populations because all fish collected showed the same color pattern. It is likely that cross-shelf variation in quality and quantity of food, as well as in turbidity, are factors that contribute to the observed patterns of growth. Similar patterns of cross-shelf mortality indicate that predation rates varied little across the shelf. Our study cautions against pooling demographic parameters on broad spatial scales without consideration of the potential for cross-shelf variabil

Comportamento sexual e uso de álcool e drogas entre homens que fazem sexo com homens no Ceará: tendências e práticas de risco para DST/AIDS

No Brasil, o s casos de AIDS entre homens que fazem sexo com homens (HSH) predominaram durante um longo período. A partir da década de 90, observa-se um declínio nesta categoria com o aumento de casos entre heterossexuais. Na região Nordeste, entretanto, os casos de AIDS entre HSH representam, ainda, cerca de 50% do total dos casos registrados em anos recentes. Nosso objetivo foi estudar o comportamento sexual e o padrão de consumo de drogas e álcool entre HSH no Ceará, enfatizando as tendências recentes e suas relações com práticas sexuais de risco para DTS/AIDS. Foram realizados quatro estudos seccionais em 1995, 1998, 2002 e 2005 no Ceará, nordeste do Brasil. A população do estudo foi composta por homens que fazem sexo com homens (HSH), com 14 anos ou mais , que referiram prática sexual anal ou oral com homens nos últimos 12 meses. A seleção dos participantes utilizou técnicas do tipo Snow Ball (1995, 1998, 2002); Time Space Sampling (2002) e Respondent Driven Sampling (2005). O primeiro artigo enfoca as tendências do comportamento sexual em Fortaleza ao longo destes quatro períodos e o segundo os preditores do consumo de álcool e drogas nos municípios de Fortaleza (n=401), Sobral (n=100) e a região do Cariri (n=100) em 2002. Análise se basearam nas comparações entre proporções, utilizando o teste do de Pearson e intervalos de 95% de confiança (IC95%) e análise de regressão logística multivariada para avaliação dos fatores associados ao consumo de álcool e drogas, utilizando-se como medida de associação a razão de chances (odds ratio OR) e seus respectivos intervalos de 95% de confiança. Resultados Práticas sexuais: Elevado percentual da população estudada referiu práticas sexuais de risco em 1995 (49,9%), decrescendo significativamente em 1998 (32,6%), tornando a crescer em 2002 (54,6%) e apresentando os menores percentuais em 2005 (31,4%). Este padrão não apresentou grandes variações por idade, mas em relação à escolaridade observou-se que os indivíduos com escolaridade mais elevada aumentaram as práticas de risco entre 1998 (28,6%) e 2002 (46,5%) decrescendo no último período (21,0%) enquanto aqueles com baixa ou média escolaridade só mostraram uma queda significativa no comportamento de risco entre 2002 (82,1% - baixa; 67,7% - média) e 2005 (29,1% - baixa; 34,3 média). A prática sexual anal com preservativo cresceu no decorrer dos anos variando de 43,3% a 53,7% entre a primeira e a última onda ( de tendência p<0.001). A relação anal sem preservativo foi uma prática com alto percentual na maioria dos anos. De 2002 a 2005, houve uma diminuição significativa (de alto percentual na maioria dos anos. De 2002 a 2005, houve uma diminuição significativa (de 57,7% para 26,3%) das relações fixas monogâmicas. Consumo de álcool e drogas: No estudo, 63% dos HSH participantes foram classificados como bebedores que se embriagam. Observou-se que o consumo crescente de álcool leva a um aumento do uso concomitante de outras drogas, sejam lícitas ou ilícitas. Foram variáveis preditoras de beber se embriagando: ter de 21 a 30 anos (OR: 1,5; IC 95%: 1,1-2,9); ter mais que 30 anos (OR: 1,6: IC95%: 1,2-2,3); ser solteiro/separado/divorciado (OR:3,0%; IC95%: 1,7-5,3); ser da raça negra (OR: 2,0 IC95%: 1,7-2,01); ser da raça parda (OR: 1,8 IC95%: 1,3-2,6); receber dinheiro por sexo (OR:2,0 IC95%: 1,8-2,9). As práticas sexuais dos SHS em Fortaleza apresentaram variações significativas ao longo doa anos estudados, semelhantemente a outros estudos internacionais. Vários fatores poderiam ser responsáveis por explicar o comportamento da curva observada em Fortaleza, seja no âmbito local, nacional ou internacional. Entre os fatores que podem explicar alterações observadas estariam: 1) redução nos recursos destinados à prevenção da AIDS no país devido a retirada de alguns organismos de cooperação internacional que se voltaram para outros países, como na África Leste Europeu, levando o Brasil a priorizar segmentos populacionais com maior vulnerabilidade; 2) grande impacto na prevenção das DST /AIDS na comunidade de homo/bissexuais masculinos, especialmente nos anos de 1998 a 2002; 3) o avanço no tratamento, surgimento de novas drogas, melhora da qualidade de vida e aumento da sobrevida, contribuindo para a construção da falsa ideia de segurança na população. Neste estudo a escolaridade mostrou-se um fator importante associado ao envolvimento em práticas sexuais não seguras. Os indivíduos com mais baixa escolaridade, no período de 1995 a 2002, se envolveram em maior risco, aparentando não terem sido atingidos pelas campanhas que possam ter ocorrido, principalmente no período de 1995 a 1998. A maior escolaridade apresenta-se como fator de proteção em todo o período estudado, provavelmente pelo maior acesso à informação. Finalmente, pode-se observar no ano de 2002 um elevado percentual de homens que consomem cinco ou mais doses em um dia típico e associam outras drogas ao consumo do álcool. Tal comportamento, dentro da população HSH, embora não seja caracterizado como dependência química, é alterado de maneira significativa pelo efeito etílico, levando à outras práticas de risco. Também se observou em nosso estudo que o consumo crescente de álcool leva a um aumento do uso de outras drogas, atuando para a adoção de comportamentos de risco. Existem evidências que suportam relação entre uso de outras drogas e a prática sexual de risco. Os indivíduos que referiram receber dinheiro em troca de sexo foram mais frequentemente classificados como bebedores que se embriagam. Os achados deste estudo mostram a importância da realização de uma vigilância comportamental contínua em relação ao HIV favorecendo o entendimento da dinâmica da epidemia junto das DST/AIDS nesta população vulnerável, assim como a importância que o álcool assume como problema de saúde pública neta população específica e a necessidade de se direcionar medidas voltadas para a sua prevenção.

Patterns of Impact Resulting from a 'Sit Less, Move More' Web-Based Program in Sedentary Office Employees

Purpose Encouraging office workers to 'sit less and move more' encompasses two public health priorities. However, there is little evidence on the effectiveness of workplace interventions for reducing sitting, even less about the longer term effects of such interventions and still less on dual-focused interventions. This study assessed the short and mid-term impacts of a workplace web-based intervention (Walk@WorkSpain, W@WS; 2010-11) on self-reported sitting time, step counts and physical risk factors (waist circumference, BMI, blood pressure) for chronic disease. Methods Employees at six Spanish university campuses (n=264; 42 +/- 10 years; 171 female) were randomly assigned by worksite and campus to an Intervention (used W@WS; n=129; 87 female) or a Comparison group (maintained normal behavior; n=135; 84 female). This phased, 19-week program aimed to decrease occupational sitting time through increased incidental movement and short walks. A linear mixed model assessed changes in outcome measures between the baseline, ramping (8 weeks), maintenance (11 weeks) and follow-up (two months) phases for Intervention versus Comparison groups. Results A significant 2 (group) x 2 (program phases) interaction was found for self-reported occupational sitting (F[3]=7.97, p=0.046), daily step counts (F[3]=15.68, p=0.0013) and waist circumference (F[3]=11.67, p=0.0086). The Intervention group decreased minutes of daily occupational sitting while also increasing step counts from baseline (446 +/- 126; 8,862 +/- 2,475) through ramping (+425 +/- 120; 9,345 +/- 2,435), maintenance (+422 +/- 123; 9,638 +/- 3,131) and follow-up (+414 +/- 129; 9,786 +/- 3,205). In the Comparison group, compared to baseline (404 +/- 106), sitting time remained unchanged through ramping and maintenance, but decreased at follow-up (-388 +/- 120), while step counts diminished across all phases. The Intervention group significantly reduced waist circumference by 2.1cms from baseline to follow-up while the Comparison group reduced waist circumference by 1.3cms over the same period. Conclusions W@WSis a feasible and effective evidence-based intervention that can be successfully deployed with sedentary employees to elicit sustained changes on "sitting less and moving more".

Can environmental constraints determine random patterns of plant species co-occurrence?

Plant community ecologists use the null model approach to infer assembly processes from observed patterns of species co-occurrence. In about a third of published studies, the null hypothesis of random assembly cannot be rejected. When this occurs, plant ecologists interpret that the observed random pattern is not environmentally constrained - but probably generated by stochastic processes. The null model approach (using the C-score and the discrepancy index) was used to test for random assembly under two simulation algorithms. Logistic regression, distance-based redundancy analysis, and constrained ordination were used to test for environmental determinism (species segregation along environmental gradients or turnover and species aggregation). This article introduces an environmentally determined community of alpine hydrophytes that presents itself as randomly assembled. The pathway through which the random pattern arises in this community is suggested to be as follows: Two simultaneous environmental processes, one leading to species aggregation and the other leading to species segregation, concurrently generate the observed pattern, which results to be neither aggregated nor segregated - but random. A simulation study supports this suggestion. Although apparently simple, the null model approach seems to assume that a single ecological factor prevails or that if several factors decisively influence the community, then they all exert their influence in the same direction, generating either aggregation or segregation. As these assumptions are unlikely to hold in most cases and assembly processes cannot be inferred from random patterns, we would like to propose plant ecologists to investigate specifically the ecological processes responsible for observed random patterns, instead of trying to infer processes from patterns