Relação entre a velocidade de nado, variação intra-cíclica da velocidade e eficiência de nado em jovens nadadores

O objetivo do presente estudo foi analisar a relação entre a velocidade de nado, a variação intra-cíclica da velocidade horizontal (dv) e a eficiência de Froude (?F) no nado crol durante três ciclos consecutivos de braçada, em nadadores jovens. A amostra foi composta por 15 nadadores do sexo masculino (16.07 ± 0.77 anos), e 15 nadadores do sexo feminino (15.05 ± 1.07 anos). A velocidade de nado e a dv foram medidos em três ciclos de braçada consecutivos durante a realização de 25 m no nado crol, à máxima intensidade. A velocidade de nado apresentou um efeito não significativo na braçada a braçada (F = 2.55, p = 0.087, ?2 = 0.08), mas um efeito de sexo significativo (F = 90.46, p < 0.001, ?2 = 0.76). A dv e ?F tiveram a mesma tendência que a velocidade de nado para o efeito braçada a braçada, mas um efeito de sexo não significativo (p > 0.05). A matriz de correlação de Spearman entre velocidade de nado e dv, e velocidade de nado e ?F revelou correlações não significativas em todos os três ciclos de braçada em ambos os sexos. No entanto, a tendência da primeira (velocidade de nado e dv) nem sempre foi inversa (valor inferior de dv e velocidade de nado superior), e a segunda (velocidade de nado e ?F) nem sempre foi direta e positiva (maior ?F e velocidade superior). Adicionalmente, a análise de modelação hierárquica HLM revelou que ?F poderá ser um preditor da velocidade de nado, mas não a dv. Os resultados demonstraram que as velocidades de nado tendem a diminuir com o tempo, mas com os nadadores a apresentarem velocidades mais elevadas em todos os ciclos de braçada analisados do que as nadadoras. Apesar de não existirem correlações significativas entre a velocidade de nado e dv ou ?F, a eficiência de Froude demonstrou ser um preditor superior, lançando a discussão acerca da importância e influência da variação intra-cíclica da velocidade para a velocidade de nado em nadadores jovens. Treinadores e nadadores devem estar cientes de que dvs mais baixos podem nem sempre estar relacionados com velocidades de nado mais rápidas e vice-versa, e que ?F entrou como um preditor de velocidade de nado em vez de dv.The aim of this study was to analyze the relationship between the swimming speed, intra-cycle variation of the horizontal speed of displacement (dv), and Froude efficiency (?F) in front-crawl during three consecutive stroke cycles. The sample consisted of 15 males (16.07 ± 0.77 years) and 15 females (15.05 ± 1.07 years). Swimming speed and dv were measured during a 25 m trial in front-crawl, at maximum intensity. Swimming speed presented a non-significant stroke-by-stroke (F = 2.55, p = 0.087, ?2 = 0.08), but a significant sex effect (F = 90.46, p < 0.001, ?2 = 0.76). The dv and ?F had the same trend as swimming speed for the stroke-by-stroke effect, but a non-significant sex effect (p > 0.05). The Spearman correlation matrix between swimming speed and dv, and swimming speed and ?F revealed non-significant correlations in all three stroke cycles in both sexes. However, the tendency of the former (swimming speed and dv) was not always inverse, and the latter (swimming speed and ?F) was not always direct and positive (greater ?F and higher speed). Additionally, HLM hierarchical modeling analysis revealed that ?F could be a predictor of swimming speed, but not dv. The results showed that swimming speeds tended to decrease over time but with male swimmers presenting higher velocities in all stroke cycles analyzed than female swimmers. Although there are no significant correlations between swimming speed and dv or ?F, the Froude efficiency proved to be a superior predictor, launching the discussion about the importance and influence of intra-cycle velocity variation for swimming speed in young swimmers. Coaches and swimmers must be aware that lower dvs may not always be related to faster swimming velocities and vice-versa and that ?F entered as a swimming speed predictor rather than dv

Contribuição para o estudo da pesca recreativa de costa em Portugal

Dissertação de Mestrado em Ciências do Mar - Recursos Marinhos, área de especialização em Biologia Marinha, apresentada ao Instituto de Ciências Biomédicas de Abel Salazar da Universidade do Port

Underwater ecotourism in the Algarve, South of Portugal: implementation and divers' perceptions

Tese de doutoramento, Ciências do Mar, da Terra e do Ambiente (Gestão Costeira), Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2013The main aims of this study on underwater ecotourism, the first in Portugal, were: 1) to develop and implement a network of underwater routes (snorkelling and scuba diving) in the Algarve, South of Portugal; 2) identify the economic valuation of snorkelling routes; 3) analyse the degree of satisfaction of users in relation to the routes and to the support infrastructures; 4) understand if the routes increase environmental awareness of divers. Three snorkelling routes were implemented in Marinha Beach along with two scuba diving routes, “B24” (off Faro city), the wreck of a World War II bomber, and “Poço” (off Armação de Pêra city), a rocky outcrop rich in biodiversity and landscaped features. All the routes were implemented in 2008, with interpretive slates at fixed locations along the route. Researchers were at the sites to answer any questions, carry out the pre diving environmental briefing, and questionnaire surveys. Based on the travel cost technique, and assuming a carrying capacity of 1000 dives per year, a total economic value for the 3 snorkelling routes of 250000€ was estimated. Most respondents perceived the existence of routes to be good for the preservation of the local biodiversity and reported this experience as “good” or “excellent”. Overall, both snorkelling and scuba routes seem to be an effective tool for developing ecological awareness in tourists, as they enhance the preservation and the understanding of the marine coastal environment. Results show that in situ education and interpretation can raise environmental awareness if properly addressed. Also, the interpretative and educational tools used seem to please visitors, resulting in a satisfactory way of engaging snorkelers in the protection of the visited environments. Overall, divers seem to consider that diving within the routes framework is more pleasant than diving without this infrastructure.O presente estudo visou analisar, pela primeira vez em Portugal, diferentes aspectos relacionados com ecoturismo subaquático e mergulho. Mais especificamente pretendeu-se: 1) criar e implementar uma rede de roteiros subaquáticos (a realizar em mergulho livre – apneia - e com escafandro autónomo – “scuba”) na região Algarvia (Sul de Portugal); 2) identificar a valorização económica efectiva da implementação dos roteiros de apneia; 3) analisar o grau de satisfação e as diferentes percepções dos utilizadores relativamente ao mergulho nos roteiros e às infra-estruturas de apoio existentes na região; 4) perceber o efeito potenciador de consciencialização ambiental dos roteiros. Para efectivar a análise do presente estudo, implementaram-se três roteiros de apneia na Praia da Marinha, e dois roteiros “scuba” em populares locais de mergulho da região: “B24”, ao largo de Faro, onde se encontra submergido um bombardeiro que afundou durante a II Guerra Mundial; e “Poço”, ao largo de Armação de Pêra, constituído por um afloramento rochoso típico da região algarvia, com elevada biodiversidade e beleza paisagística. Os roteiros foram implementados em 2008, com placas interpretativas localizadas em pontos pré-definidos ao longo dos percursos. Uma equipa de investigadores foi disponibilizada para apoio nos diversos locais de mergulho, por forma a efectuar os briefings ambientais prévios ao mergulho, dar o apoio logístico necessário e efectivar os questionários pós mergulho. De acordo com o método do custo de viagem, e assumindo uma capacidade de carga de 1000 mergulhos/ano, o valor económico total referente aos três roteiros de apneia foi estimado em 250000€. A maior parte dos mergulhadores classificam a experiência de mergulhar em roteiros como “boa” ou “excelente”. Na generalidade, tanto os mergulhadores de apneia como os de escafandro autónomo consideram os roteiros uma ferramenta interessante e eficiente para o desenvolvimento da actividade e para a sua promoção na região. Paralelamente, as vertentes de educação e interpretação ambiental associadas aos roteiros parecem agradar aos visitantes, estimulando de forma efectiva o conhecimento e a preservação do meio envolvente e, em consequência, potenciando a consciencialização ambiental dos mergulhadores. De uma forma geral, os mergulhadores consideram mais satisfatório mergulhar em locais de mergulho com roteiros implementados

Assessing the land- and seascape determinants of recreational diving: evidence for Portugal’s south coast

Scuba diving is one of the most popular coastal recreational activities, and one of the few that are allowed in multiple-use marine protected areas. Nevertheless, like many other coastal activities, if in excess, it may harm coastal ecosystems and their sustainable use. This paper focuses on the seascape and landscape characteristics that are most associated with the existence of dive sites, aiming to identify other suitable locations along the coast to potentially reduce environmental pressure (e.g., overcrowding and physical damage) on the existing dive sites. Logistic regressions were employed to model the suitability for dive sites existence in the Portuguese south coast (Algarve), one of the most popular Summer destinations in mainland Europe. Results suggest that closeness to waterlines and piers and the presence of rock structures in the coastal strip are the most important attributes that positively influence dive sites’ existence, whereas the beach environment and the presence of muddy sediments are negatively associated with it. In this study, we suggest the application of a logistic model to find alternatives for the explored dive sites as a quick and easily applied coastal management tool. Moreover, we find it useful for the implementation of coastal conservation strategies extended to other coastal activities.FCT: PD/BD/143087/2018/ SFRH/BPD/116307/2016; MCTES for the financial support to CESAM UIDB/50017/2020; CCMAR: UIDB/04326/2020info:eu-repo/semantics/publishedVersio

Effects of different slipping methods on the mortality of sardine, Sardina pilchardus, after purse-seine capture off the Portuguese Southern coast (Algarve)

The effects of two different slipping methods on the survival, physical and physiological response of sardines, Sardina pilchardus, captured in a purse-seine fishery were investigated in southern Portugal. Sardines were collected and transferred into holding tanks onboard a commercial fishing vessel after being captured, crowded and deliberately released using two slipping procedures: standard and modified. The standard slipping procedure aggregated fish at high densities and made them "roll over" the floatline, while the modified procedure aggregated the fish at moderate densities and enabled them to escape through an opening created by adding weights to the floatline. Both slipping methods were compared with minimally harmed non-slipped sardines (sardines collected from the loose pocket of the purse seine). Survival rates were monitored in captivity over 28 days using three replicates for each treatment. The estimated survival of sardines was 43.6% for the non-slipped fish, 44.7% for the modified slipping and 11.7% for the standard slipping treatments. Scale loss indicated the level of physical impact experienced, with dead fish from the non-slipped and modified slipping technique showing significantly lower scale loss than those fish from the standard slipping treatment within the same period. Of the physiological indicators of stress measured, cortisol, glucose, lactate and osmolality attained peak values during slipping and up to the first hours after introduction to captivity. This work indicates that although delayed mortality after release may be substantial, appropriately modified slipping techniques significantly enhance survival of slipped sardines.FCT [SFRH/BPD/116307/2016]; European Commission's Horizon 2020 Research and Innovation Programme [634495

Design and development of a microfuidic paper-based analytical device for calcium determination in saliva

info:eu-repo/semantics/publishedVersio

Microfluidic paper-based analytical device for the determination of salivary calcium

info:eu-repo/semantics/publishedVersio

Quantification of salivary magnesium using a microfluidic paper based analytical device (μPAD)

info:eu-repo/semantics/publishedVersio

Reducción de la captura secundaria y los descartes en la pesquería costera de pequeña escala del Algarve utilizando una red de trasmallo de monofilamento equipada con una red de protección

Experimental fishing was conducted off the port of Quarteira (southern Portugal) from October 2016 to February 2017 using standard trammel nets and modified nets rigged with a guarding net. The commercial catches of trammel nets rigged with a guarding net were 46.1% and 38.0% less than those of the standard net in numbers and economic value. However, there were significantly fewer commercial discards in biomass in the modified trammel nets (68.2%) and by-catch abundance and biomass were also lower in the modified nets (41.8% and 17.3% less, respectively). For the two main fish by-catch species, the modified net caught 62.2% fewer longfin gurnards (C. obscurus) and 33.1% fewer greater weever (T. draco) than the standard nets. Timing the removal from the nets of the main by-catch and discards species revealed savings in time associated with the use of modified nets. However, net damage occurred twice as much as in the modified net, probably contributing to the reduced commercial catches. The results indicate that trammel nets with the guarding net reduce by-catch and discards and save time, but are unlikely to be adopted by fishers targeting soles due to the higher costs of the modified nets and losses in commercial catches and earnings.European Commission's Horizon 2020 Research and Innovation Programme - 634495info:eu-repo/semantics/publishedVersio

Do fisher associations really represent their members’ needs and opinions? The case study of the octopus fishery in the Algarve (south Portugal)

Fishers’ participation in the fishery management decision-making process is generally low, particularly in small-scale fisheries (SSF). Within the overarching goal of improving fisheries governance, fishers’ participation is crucial. Yet, how can fishers participate in the decision-making processes which affect their actions, and to what extent do fisher associations represent their interests? These questions were tackled by means of an empirical case study in the “Tertúlia do Polvo” project, focusing on the octopus SSF in the Algarve region (south Portugal), where the octopus fishery is managed top-down with sporadic participation of fishers. During the study (2014 and 2015), seven participatory workshops (tertúlias) were held, involving fisher associations, management authorities and researchers, to propose and discuss management measures for the fishery. Also, a face-to-face questionnaire survey (121 valid replies) was undertaken with local fishers to gauge their opinions about the management measures proposed during the workshops. Results show a strong agreement between the outcomes achieved during the workshops and the main concerns and possible solutions identified by fishers. Taking into consideration the difficulty in structuring and assuring a transparent and effective participation of fishers in the management of their activity, the results obtained are promising. In this study, the use of a participatory process (restricted to a small group of stakeholders) combined with consultation (targeting a sample of the fisher population) allowed the validation of the overall results obtained. Such a methodological approach can be tried in other fishing communities to implement efficient and effective collaborative management, contributing to improved fisheries governance.FCT: SFRH/BPD/116307/2016. PROMAR: 31-03-01-FEP-200.info:eu-repo/semantics/publishedVersio