Mauve Stingers (Pelagia noctiluca) as carriers of the bacterial fish pathogen Tenacibaculum maritimum

Aggregations or blooms of jellyfish are increasingly problematic for the aquaculture industry. Jellyfishassociated mass mortalities of sea-caged fish are most often caused by swarms of oceanic species like Pelagia noctiluca. These relatively large jellyfish get carried by tides and currents onto fish cages, causing them to break up into pathogenic nematocyst-containing pieces that are capable of passing through the mesh of the cages. The main effect on fish is gill damage leading to respiratory distress, but the lesions may also be compounded by bacterial infection, Tenacibaculum maritimum being one of the pathogens involved. In our previous study, we highlighted the ability of the jellyfish Phialella quadrata to carry this important pathogen. However, since these small jellyfish were collected around sea-cages of infected salmon, it was not possible to determine if the jellyfish or the fish themselves were the original source of the bacteria. Results of the current study demonstrate that these filamentous bacteria are present on the mouth of P. noctiluca that had no previous contact with farmed fish. These new results highlight the fact that some Cnidarian species harbour T. maritimum and suggest that jellyfishmight be a natural host for these bacteria whose environmental reservoir has not yet been determined.

The Secret Life of Oilbirds: New Insights into the Movement Ecology of a Unique Avian Frugivore

Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil.

Stable isotopes challenge the perception of ocean sunfish Mola mola as obligate jellyfish predators

Evidence is provided from stable isotope analysis that aggregations of small ocean sunfish Mola mola (total length <1 m) feed broadly within coastal food webs and their classification as obligate predators of gelatinous zooplankton requires revision.

Efficiency of starfish mopping in reducing predation on cultivated benthic mussels (Mytilus edulis Linnaeus)

The starfish, Asterias rubens, preys on mussels (Mytilus edulis), which are relaid during benthic cultivation processes. Starfish mops, a modified dredge used to remove starfish from mussel cultivation beds, are used in several fisheries today but few studies have attempted to quantify the effectiveness of this method in removing starfish. This study tested the effectiveness of starfish mopping to reduce starfish numbers on mussel beds in Belfast Lough, Northern Ireland. Video surveys to determine starfish densities on mussel beds were conducted between October 2013 and December 2014 using a GoPro™ camera attached to starfish mops. This allowed us to firstly test whether starfish density varied among mussel beds and to investigate how fluctuations in starfish numbers may vary in relationship to starfish ecology. We then estimated the efficiency of mops at removing starfish from mussel beds by comparing densities of starfish on beds, as determined using video footage, with densities removed by mops. Starfish abundance was similar among different mussel beds during this study. The efficiency of mops at removing estimated starfish aggregations varied among mussel beds (4–78%) and the mean reduction in starfish abundance was 27% (± SE 3.2). The effectiveness of mops at reducing starfish abundance was shown to decline as the initial density of starfish on mussel beds increased. It can be recommended that the exact deployment technique of mops on mussel beds should vary depending on the density of starfish locally. The area of mussel bed covered by mops during a tow, for example, should be less when starfish densities are high, to maintain efficiencies throughout the full length of tows and to optimise the removal of starfish from mussel beds. This strategy, by reducing abundance of a major predator, could assist in reducing losses in the mussel cultivation industry.

Gene-associated markers can assign origin in a weakly structured fish, Atlantic herring

Regulations on the exploitation of populations of commercially important fish species and the ensuing consumer interest in sustainable products have increased the need to accurately identify the population of origin of fish and fish products. Although genomics-based tools have proven highly useful, there are relatively few examples in marine fish displaying accurate origin assignment. We synthesize data for 156 single-nucleotide polymorphisms typed in 1039 herring, Clupea harengus L., spanning the Northeast Atlantic to develop a tool that allows assignment of individual herring to their regional origin. We show the method's suitability to address specific biological questions, as well as management applications. We analyse temporally replicated collections from two areas, the Skagerrak (n = 81, 84, 66) and the western Baltic (n = 52, 52). Both areas harbour heavily fished mixed-origin stocks, complicating management issues. We report novel genetic evidence that herring from the Baltic Sea contribute to catches in the North Sea, and find support that western Baltic feeding aggregations mainly constitute herring from the western Baltic with contributions from the Eastern Baltic. Our study describes a general approach and outlines a database allowing individual assignment and traceability of herring across a large part of its East Atlantic distribution.

Moytirra:Discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores

Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45^oN. This is the only high temperature hydrothermal vent known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra vent field is, unusually for tectonically controlled hydrothermal vents systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra vent field consists of an alignment of four sites of venting, three actively emitting "black smoke," producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously venting. The vent fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the vent chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the vent field. The discovery of the Moytirra vent field therefore expands the known latitudinal distributions of several vent-endemic genera in the north Atlantic, and reveals faunal affinities with vents south of the Azores rather than north of Iceland. © 2013. American Geophysical Union. All Rights Reserved.

Identity of a Tilapia Pheromone Released by Dominant Males that Primes Females for Reproduction

Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet it is necessary in order to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication [1]. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies, and females mate preferentially with dominant territorial males, which they visit in aggregations or leks [2]. Dominant males have thicker urinary bladder muscular walls than subordinates or females and store large volumes of urine, which they release at increased frequency in the presence of subordinate males or preovulatory, but not postspawned, females [3–5]. Females exposed to dominant-male urine augment their release of the oocyte maturation-inducing steroid 17α,20β-dihydroxypregn-4-en-3-one (17,20β-P) [6]. Here we isolate and identify a male Mozambique tilapia urinary sex pheromone as two epimeric (20α- and 20β-) pregnanetriol 3-glucuronates. We show that both males and females have high olfactory sensitivity to the two steroids, which cross-adapt upon stimulation. Females exposed to both steroids show a rapid, 10-fold increase in production of 17,20β-P. Thus, the identified urinary steroids prime the female endocrine system to accelerate oocyte maturation and possibly promote spawning synchrony. Tilapia are globally important as a food source but are also invasive species, with devastating impact on local freshwater ecosystems [7, 8]. Identifying the chemical cues that mediate reproduction may lead to the development of tools for population control [9–11].

Gerir tensões na complexidade organizacional de um agrupamento de escolas : testemunho da sua diretora

Trabalho de projeto de mestrado, Ciências da Educação (Administração Educacional), Universidade de Lisboa, Instituto de Educação, 2013

Estratégias de liderança de um diretor escolar

Trabalho de projeto de mestrado, Ciências da Educação (Administração Educacional), Universidade de Lisboa, Instituto de Educação, 2013

Zooplankton community structure in response to turbulent flow over a sill in Nootka Sound

Senior thesis written for Oceanography 445

Distributed generation producers' reserve management

Sustainable development concerns are being addressed with increasing attention, in general, and in the scope of power industry, in particular. The use of distributed generation (DG), mainly based on renewable sources, has been seen as an interesting approach to this problem. However, the increasing of DG in power systems raises some complex technical and economic issues. This paper presents ViProd, a simulation tool that allows modeling and simulating DG operation and participation in electricity markets. This paper mainly focuses on the operation of Virtual Power Producers (VPP) which are producers’ aggregations, being these producers mainly of DG type. The paper presents several reserve management strategies implemented in the scope of ViProd and the results of a case study, based on real data.

Interactions of diploid embryonal carcinoma cells and normal cell mass cells with 2.5 day mouse embryos following aggregation

Spontaneous teratocarcinomas are ovarian or testicular tumors which have their origins in germ cells. The tumors contain a disorganized array of benign differentiated cells as well as an undifferentiated population of malignant stem cells, the embryonal carcinoma or EC cells. These pluripotent stem cells in tissue culture share many properties with the transient pluripotent cells of the early embryo, and might therefore serve as models for the investigation of developmental events ill vitro. The property of EC cells of prime interest in this study is an in vivo phenomenon. Certain EC cell lines are known to be regulated ill vivo and to differentiate normally in association with normal embryonic cells, resulting in chimeric mice. These mice have two genetically distinct cell populations, one of which is derived from the originally malignant EC cells. This has usually been accomplished by injection of the EC cells into the Day 3 blastocyst. In this study, the interactions between earlier stage embryos and EC cells have been tested by aggregating clumps of EC cells with Day 2 embryos. The few previous aggregation studies produced a high degree of abnormality in chimeric embryos, but the EC cells employed had known chromosomal abnormalities. In this study, two diploid EC cell lines (P19 and Pi0) were aggregated with 2.5 day mouse embryos, and were found to behave quite differently in the embryonic environment. P19 containing aggregates generally resorbed early, and the few embryos recovered at midgestation were normal and non-chimeric. Pi0 containing aggregates survived in high numbers to midgestation, and the Pi0 cells were very successful in colonizing the embryo. All these embryos were chimeric, and the contribution by the EC cells to each chimera was very high. However, these heavily chimeric embryos were all abnormal. Blastocyst injection had previously produced some abnormal embryos with high Pl0 contributions in addition to the live born mice, which had lower EC contributions. This study now adds more support to the hypothesis that high EC contributions may be incompatible with normal development. The possibility that the abnormalities were due to the mixing of temporally asynchronous embryonic cell types in the aggregates was tested by aggregating normal pluripotent cells taken from 3.5 day embryos with 2.5 day embryos. Early embryo loss was very high, and histological studies showed that the majority of these embryos died by 6.5 days development. Some embryos escaped this early death such that some healthy chimeras were recovered, in contrast to recovery of abnormal chimeric embryos following Pl0-morula aggregations, and non-chimeric embryos following P19-morula aggregations. This somewhat surprising adverse effect on development following aggregation of normal cell types suggests that there are developmental difficulties associated with the mixing of asynchronous cell types in aggregates. However, the greater magnitude of the adverse effects when the aggregates contained tumor derived cells suggests that EC cells should not be considered the complete equivalent of the pluripotent cells of the early embryo.

Microphytoplankton community structure in the North Eastern Arabian Sea during Winter Monsoon

The overall attempt of the study was aimed to understand the microphytoplankton community composition and its variations along a highly complex and dynamic marine ecosystem, the northern Arabian Sea. The data generated provides a first of its kind knowledge on the major primary producers of the region. There appears significant response among the microphytoplankton community structure towards the variations in the hydrographic conditions during the winter monsoon period. Interannually, variations were observed within the microphytoplankton community associated with the variability in temperature patterns and the intensity of convective mixing. Changing bloom pattern and dominating species among the phytoplankton community open new frontiers and vistas towards more intense study on the biological responses towards physical processes. The production of large amount of organic matter as a result of intense blooming of Noctiluca as well as diatoms aggregations augment the particulate organic substances in these ecosystem. This definitely influences the carbon dynamics of the northern Arabian Sea. Detailed investigations based on time series as well as trophodynamic studies are necessary to elucidate the carbon flux and associated impacts of winter-spring blooms in NEAS. Arabian sea is considered as one among the hotspot for carbon dynamics and the pioneering records on the major primary producers fuels carbon based export production studies and provides a platform for future research. Moreover upcoming researches based on satellite based remote sensing on productivity patterns utilizes these insitu observations and taxonomic data sets of phytoplankton for validation of bloom specific algorithm development and its implementation. Furthermore Saurashtra coast is considered as a major fishing zone of Indian EEZ. The studies on the phytoplankton in these regions provide valuable raw data for fishery prediction models and identifying fishing zones. With the Summary and Conclusion 177 baseline data obtained further trophodynamic studies can be initiated in the complex productive North Eastern Arabian Seas (NEAS) ecosystem that is still remaining unexplored.

Spatial Aggregation of Forest Songbird Territories and Possible Implications for Area Sensitivity

Habitat area requirements of forest songbirds vary greatly among species, but the causes of this variation are not well understood. Large area requirements could result from advantages for certain species when settling their territories near those of conspecifics. This phenomenon would result in spatial aggregations much larger than single territories. Species that aggregate their territories could show reduced population viability in highly fragmented forests, since remnant patches may remain unoccupied if they are too small to accommodate several territories. The objectives of this study were twofold: (1) to seek evidence of territory clusters of forest birds at various spatial scales, lags of 250-550 m, before and after controlling for habitat spatial patterns; and (2) to measure the relationship between spatial autocorrelation and apparent landscape sensitivity for these species. In analyses that ignored spatial variation of vegetation within remnant forest patches, nine of the 17 species studied significantly aggregated their territories within patches. After controlling for forest vegetation, the locations of eight out of 17 species remained significantly clustered. The aggregative pattern that we observed may, thus, be indicative of a widespread phenomenon in songbird populations. Furthermore, there was a tendency for species associated with higher forest cover to be more spatially aggregated [ERRATUM].

California's Endangered Belding’s Savannah Sparrow (Passerculus sandwichensis beldingi): Tolerance of Pedestrian Disturbance

Salt marshes constitute habitat islands for many endemic animal species, particularly along the California coast, where urban sprawl has fragmented this habitat. Recreational activities in salt marshes have increased recently, posing an interesting problem: how do endemic species lacking alternative habitat modify their tolerance to humans? We assessed seasonal and site variations in three tolerance parameters (distances at which animals became alert, fled, and moved after fleeing) of California's endangered Belding’s Savannah Sparrow ((Passerculus sandwichensis beldingi). We approached individuals on trails in three salt marshes with different levels of vehicle and pedestrian traffic. Belding’s Savannah Sparrows became aware and fled at shorter distances in the salt marsh coincident with greater levels of recreational activity as a result of habituation or visual obstruction effects. Seasonal effects in tolerance varied between sites. Alert and flight initiation distances were higher in the pre-nesting than in the non-breeding season in the site with the highest levels of recreational use likely due to greater exposure of breeding individuals; however, the opposite seasonal trend was found in each of the two sites with relatively lower human use, probably because individuals were less spatially attached in the non-breeding season when they foraged in aggregations. Distance fled was greater in the non-breeding than in the breeding season. Our findings call for dynamic management of recreational activities in different salt marshes depending on the degree of exposure to humans and seasonal variations in tolerance. We recommend a minimum approaching distance of 63 m and buffer areas of 1.3 ha around Belding's Savannah Sparrows.