Pit telemetry as a method to study the habitat requirements of fish populations. Application to native and stocked trout movements

Passive integrated transponder (PIT) technology was used to study the behaviour of fishes during the summer season in two headwater streams of northeastern Portugal. A total of 71 PIT tags (12 mm long x 2.1 mm diameter) were surgically implanted in 1+ stocked (39) and native (32) brown trout of two size classes (< 20.0 and ≥ 20.0 cm). Eight independent antennae, connected to a multi-point decoder (MPD reader) unit, were placed in different microhabitats, selected randomly every three days during the observation period (29 August to 9 September in Baceiro stream and 19 September to 4 October in Sabor stream). The results confirmed this method as a suitable labour efficient tool to assess the movement and habitat use of sympatric stocked and native trout populations. About 76.9% of stocked and 59.4% of native PIT tagged trouts were detected. Multivariate techniques (CCA, DFA and classification tree) showed a separation in habitat use between the two sympatric populations. Stocked trout used, mainly, the microhabitats located in the middle of the channel with higher depths and without cover. Furthermore, these fishes displayed a greater mobility and a diel activity pattern different to native trout populations

Que nos dizem as comunidades de macroinvertebrados acerca dos impactos do colapso das escombreiras das minas do Portelo (NE Portugal)?

Em Janeiro de 2010 em consequência de um evento de precipitação extrema uma grande parte dos materiais armazenados nas escombreiras das minas do Portelo foi arrastada para os cursos de ágLia circundantes. Com o objetivo de avaliar as consequências deste evento na integridade ecológica dos cursos de água adjacentes foram amostradas as comunidades de macroinvertebrados aquáticos em vários pontos. Os resultados indicam que nos pontos mais afastados da mina (a mais de 20 Km de distância) os efeitos parecem ter sido negligenciáveis não se verificando alteração significativa nas comunidades. No entanto, nos pontos mais próximos da mina as comunidades foram arrasadas não tendo sido amostrados quaisquer organismos durante 2010. A recolonização das áreas mais afetadas só ocorreu a partir da primavera de 2011 . Durante os 3 anos em que decorreu o presente estudo as comunidades de macroinvertebrados nas áreas mais afetadas nunca recuperaram o seu estado inic ial. Este estudo demonstra que as comunidades de macroinvertebrados também podem ser utilizadas como indicadores para avaliar os impactos da contaminação proveniente da atividade mineira na integridade ambiental

Combining radio and Pit telemetry to study the large and fine-scale movements of stocked and wild brown trout (Salmo trutta L.) in a Northeastern stream, Portugal

Radio and Passive Integrated Transponder (PIT) telemetry were used to monitor the movements of stocked and wild trout, Salmo trutta L., in a north-eastern Portuguese stream. Large scale-movement analyses using radio-telemetry showed: 1) After 14 days (September 2002), the stocked fish (270 mm in total length LT) movements were significantly higher and dispersed 1,500 m from wild trout (330 mm LT), which remained near of the stocking site; 2) At the end of 64 days (September to November 2005), 83.3% of stocked tagged trout (255-277 mm, LT) dispersed in downstream direction ranging from 200 to 4,100 m. Dispersal, daily home range and distance moved of fish that displayed higher mobility were significantly different from the more stationary fish and highly correlated (rS> 0.75) with discharge. Furthermore, even in fine-scale analysis, using PIT telemetry (12 August to 30 September 2005) stocked fish (50 individuals, 185-262 mm LT) movements were significantly greater than wild trout (25 native trout, 132-250 mm LT) and differed in the diel activity pattern, which was higher during dawn and night periods, decreasing at dusk period. Only 28% of the hatchery-reared fish survived and the lower condition and the vulnerability to predation by otter (Lutra lutra) were detected as the main causes to the mortality registered

Diet of stocked and wild trout, Salmo trutta: Is there competition for resources?

Stocked and native trout diet was assessed in two north-eastern Portugal headstreams during the summer season of three successive years (2000 to 2002). Significant differences were detected in the diet composition between stocked (age 1+) trout and distinct size-class of native trout. Stocked fish showed preference, almost exclusively, for food items captured near the surface (primarily terrestrial adult insects), emergent pupae and subimagos. In contrast, young-of-year (YOY) native trout fed predominantly on the most available aquatic prey taxa such as Chironomidae (Diptera) larvae and Baetidae (Ephemeroptera) nymphs; however, Trichoptera larvae were not taken. Native trout preference changed from benthic aquatic invertebrates to terrestrial origin organisms and this ratio increased with size, suggesting an ontogenetic diet variation. Significant diet overlap was only detected between stocked and dominant native trout, which were not displaced from the energetically profitable areas. Therefore, this study showed the absence of an evident competition for food in both streams, even when trout density was largely augmented by stocking activity. However, since no obvious benefits on space and time were obtained, stocking must be carefully evaluated and alternative approaches considered, like habitat improvement and adequate fisheries management, in order to increase the natural productivity of these systems

As provas de grupo no processo de selecção para a Academia Militar : a importância de estudos psicométricos

Tese de mestrado em Psicologia (Psicologia dos Recursos Humanos), apresentada à Universidade de Lisboa através da Faculdade de Psicologia e de Ciências da Educação, 2008Esta dissertação teve por fundamentação teórica a literatura relativa à Selecção de pessoal, mais especificamente, a Selecção pelas competências através do método de assessment center. Neste enquadramento, constituíram-se como objectivos gerais desta investigação, a actualização das Provas de Grupo utilizadas na Selecção para a Academia Militar, bem como a realização de estudos psicométricos para determinar a sua precisão, validade interna de construto e possibilidade de elaboração de normas para o Escalonamento de Avaliação Global (EAG). As Provas de Grupo, constituídas pela Prova de Projecto de Planeamento e Prova de Obstáculos, foram aplicadas a uma amostra de 417 candidatos, durante o processo de Selecção para a Academia Militar, no ano de 2007. Nos resultados destacam-se a elevada precisão inter-observadores com existência de elevados alfas de Cronbach para as dimensões, o que parece indicar que as mesmas foram bem definidas operacionalmente e incorporam indicadores comportamentais precisos e fáceis de observar. Outro aspecto importante, é que as distribuições dos resultados das dimensões seguem o padrão da curva normal, o que permitiu a elaboração de normas para o EAG. No que diz respeito à validade interna de construto, não existe evidência clara da mesma, contudo, existem indícios da sua existência, nomeadamente, alguma validade discriminante para a Prova de Projecto de Planeamento e moderadas validades convergentes para as dimensões Persuasão/Negociação e Trabalho de equipa , com valores mais elevados para a primeira. Assim, poder-se-á afirmar que as provas possuem características psicométricas satisfatórias para serem utilizadas na fase final do processo de Selecção para a Academia Militar, e poderão contribuir decisivamente para o aumento do rigor e equidade neste processo de Selecção. Por último, foram tecidas considerações sobre as limitações do estudo e levantadas hipóteses para investigações futuras.This dissertation had as theoretical foundation the literature on personnel Selection's subject, more specifically, the Selection based on competencies by using assessment center method. In this context, in the present investigation were defined as general aims the updating of the Group Exercises applied in the Selection process for the Military Academy, as well as the elaboration of psychometric studies to determine their reliability, internal construct validity and also the possibility of establishing norms for the Overall Assessment Rating (OAR). The Group Exercises, constituted by Project Planning Exercise and Obstacle Exercise, were applied to a sample of 417 candidates, during the Selection process for Military Academy, in the year of 2007. The results stand out high inter-rater reliability with an existence of high Cronbach alphas for the dimensions, suggesting that they were well defined operationally and incorporate behavioural indicators that are reliable and easy to observe. Another important issue is that the results distributions of the dimensions follow the pattern of a normal curve, which allowed the development of norms for the OAR. Regarding to internal construct validity, results do not show a clear evidence of it, although there are signs of its existence, namely, some discriminant validity for the Project Planning Exercise and moderate convergent validities for the dimensions Persuasion/Negotiation and Team work , with higher values for the first one. Therefore, not only is it possible to state that the Group Exercises have satisfactory psychometric characteristics for use at the final stage of the Selection process for the Military Academy, but also may contribute decisively to increase the accuracy and equity in this Selection process. Finally, some considerations were made about the limitations of the present study and were raised hypothesis for future research

Habitat improvement and restocking of salmonid streams in Northeastern Portugal

Através do recurso à PIT-Telemetria (Passive Integrated Transponder Telemetry) foi avaliado o comportamento de populações de truta (Salmo trutta L.) no verão de 2010, no rio Penacal (nordeste de Portugal), num troço de aptidão exclusivamente salmonícola. Todos os peixes foram marcados com base na implantação cirúrgica de PIT-tags (12,0 mm comprimento x 2,1 mm diâmetro) na cavidade intraperitoneal. Foram consideradas 3 populações de truta: 1) trutas selvagens, provenientes do local de origem, de várias idades (n= 20; 8,0-16,0 cm LT; 4,5-29,8 g); e 2) trutas domésticas, com idade 1+ (12,5-18,1 cm LT; 16,8-59,9 g), criadas em 2 modalidades distintas: 2a) moldes convencionais (n= 20; tanques de cimento e alta densidade), 2b) aclimatação ao meio selvagem (n= 20; tanques de terra e baixa densidade). Os dados foram registados por um MPD (multi-point decoder) conectado a 8 antenas independentes, colocadas em diferentes microhabitats, selecionados aleatoriamente e reposicionados cada três dias, durante o período de 7 semanas de monitorização. Procedeu-se também à melhoria do habitat com incorporação de blocos e vegetação num troço delimitado por redes. Os resultados confirmaram a eficiência do método na avaliação do movimento e uso do habitat pelas populações simpátricas de trutas domésticas e selvagens. Detetaram-se respetivamente 80% e 60% das trutas domésticas e nativas no período de estudo. As técnicas multivariadas (NMDS, dbRDA) mostraram a separação no uso do habitat entre as três populações de trutas. As trutas de cativeiro criadas de modo convencional usaram principalmente os microhabitats localizados no centro do canal, com maiores profundidades e praticamente sem cobertura. Complementarmente, estes peixes evidenciaram uma maior taxa de mobilidade e um padrão de atividade diferente das trutas selvagens e das trutas domésticas aclimatadas em tanques de terra, que demonstraram uma melhor capacidade de adaptação ao meio aquático, nomeadamente à melhoria do habitat promovida.Passive integrated transponder (PIT) technology was used to study the behaviour of fishes during the summer season of 2010 in the River Penacal, a salmonid headstream of northeastern Portugal. A total of 60 PIT tags (12.0 mm long x 2.1 mm diameter) were surgically implanted into the intraperitoneal cavity of fish. Three trout populations were considered: 1) native brown trout of different age classes (8.0-16.0 cm LT, 4.5-29.8 g) (n= 20 individuals, previously captured by electrofishing in the study site) and 2) stocked trout, age 1+ (12.5-18.1 cm LT, 16.8-59.9 g) reared in different conditions 2a) traditional cement raceways (n=20) and 2b) natural (land) tanks (n=20). Eight independent antennae, connected to a multi-point decoder (MPD reader) unit, were placed in different microhabitats, selected randomly every three days, during the observation period (7 weeks). Fish habitat improvement was made recurring to blocks and vegetation in order to promote refugee. The results confirmed this method as a suitable labour efficient tool to assess the movement and habitat use of stocked and native trout populations. About 80% of stocked and 60% of native PIT tagged trout were detected. Multivariate techniques (NMDS, dbRDA) showed a separation in habitat use between the three sympatric populations. Stocked trout, reared in conventional raceway tanks with high densities used, mainly, the microhabitats located in the middle of the channel with higher depths and without cover. Furthermore, these fishes displayed a greater mobility and a different activity pattern in comparison with the native and the acclimated trout populations, which displayed a better adaptation to the aquatic environment, namely to the habitat improvement promoted. Keywords: Salmo trutta, habitat improvement, stocking, PIT-telemetr

A faunal and historical survey of sialidae (insecta: megaloptera) in continental Portugal

Despite the existence of two old, but well known, publications that cite Portuguese localities for the Sialidae (McLachlan, 1880; Navás, 1908), all more recent faunal works fail to report this family from Portugal (e.g., Monserrat, 1986; Aspöck et al., 2001; Aspöck & Aspöck, 2011). We have recently reported Sialidae as a new taxon from Portugal (Badano et al., 2011), but Megaloptera turn out to be relatively well known to aquatic biologists in Portugal (Teixeira et al., 2009). Here, a survey of the distribution of Sialidae in continental Portugal is presented within the framework of a collaboration with the Portuguese biodiversity project NaturData

Changes in plasma electrolytes and behavior of freshwater fish, Luciobarbus bocagei, as a function of acute copper exposure

Plasma levels of Na+, K+ and Ca2+ were evaluated in fish exposed / not exposed to sublethal concentrations of Cu to assess adverse effects on osmoregulation as well as their ability to reverse these levels. Acute toxicity tests were performed using barbells (Luciobarbus bocagei) under two different concentrations of Cu. Barbells exposed to Cu showed ionic imbalance, respiratory difficulties, mortality and reduced value of K. According to the results, plasma levels of K+ and Ca2+ increase, while plasma levels of Na+ decrease, allowing the fish an osmotic adjustment and a reduction in susceptibility to Cu. Under the conditions of this experiment, fish also showed the ability to reverse electrolyte levels when they are no longer exposed to Cu; however, dependent on exposure concentration.info:eu-repo/semantics/publishedVersio

ZPR of the Olo river: management of sport fishing

This work is the result of sport fishing monitoring carried out in 2013 in the Reserved Fisheries Zone (ZPR) of the Olo River. The aim of this initiative was to evaluate whether the management model, initially established, would require, after six years of implementation, eventual modifications, and to stabilize, in a Management Plan, the recreational sport fishing activity during the next years of activity. This study respected the methodology originally adopted (2007). In the conservation status assessment of the fish communities, the data concerning age, growth, physical condition and their relationship with the different habitat types where they were captured were analyzed. The results showed that the brown trout and the northern chub are once more the species with the most spatial distribution (found along the entire river). Also, revealed that the salmonid was present in all the sampling stations with water available throughout the year. The recent occurrence of a trout specimen at the age of 6+, in a monitoring action, determined the increase in 2016 of one year in the maximum longevity obtained by this species. In 2013, Gobio lozanoi had a strong expression in the lower section (1/3) of the river, especially with very young individuals (0+). Its occurrence is strongly associated with anthropic actions (illicit introductions) in more lentic habitats, where the water temperature is higher in summer. Overall, the longitudinal variation of the species is directly associated with the quality of the freshwater habitat. It was also possible to assess the pertinence of the adoption of complementary measures to improve the sustainable management of sport fishing in the Olo River ZPR (Ordinance no. 206/2008, of February 25), which are proposed in the Plan Management of the Olo River ZPR.info:eu-repo/semantics/publishedVersio

Acoustic and light selective behavioral guidance systems for freshwater fish

The use of non-physical barriers, particularly based on acoustic and luminous stimuli has been historically used to influence the behavior of fish, mainly for fishing purposes. Nowadays, behavioral barriers and guidance systems have been developed, not only to deter movements of fish, but also to promote behavioral responses with the objective of native fish protection, in particular the potamodromous species, reducing their mortality in the hydraulic structures of dams and guiding them towards transposition systems or to replacement habitats in regularized water bodies. This review details the use of acoustic and luminous systems and their evolution in recent years (Scopus 2012–2019) for the development of selective behavioral barriers for fish. We found that recent technologies try to identify new acoustic and luminous sensory ranges. Ambient sound, sound of predators or luminous spectral bands with different wavelengths have been used to selectively stimulate target and non-target species, in order to improve the effectiveness of repulsive/attractive systems for fish. Guidelines for future research in the area are also present.This work is supported by National Funds by FCT—Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020.info:eu-repo/semantics/publishedVersio