The essence of this work is employment of IT and mathematical methods in development of remote applications with dynamically changing media. Analysis and practical use of methods are based on instances of internet games. The main groups and peculiarities of rapidly growing entertainment form – internet games – and programming technologies and languages used in development of such games are presented. Multiplayer multisession internet games with persistent world are analyzed. The main purpose of work is to highlight such games' dynamic aspects and implementing solutions. Differences and similarities of dynamics in real time games and turn-based games are highlighted with aim to integrate strength of both groups. Goals of work are analysis of methods and implementation of factors which influence game dynamics: user activity synchronization, persistent and changing game environment, data streaming. Implementation solutions are submitted in form of multiplayer real time internet game "Žvejyba".

Worldwide, finfish fisheries receive increasing assessment and regulation, slowly leading to more sustainable exploitation and rebuilding. In their wake, invertebrate fisheries are rapidly expanding with little scientific scrutiny despite increasing socio-economic importance. This thesis provides the first global analysis of the trends, drivers, and population and ecosystem consequences of invertebrate fisheries, in general, and sea cucumber fisheries, in particular, based on a global catch database in combination with taxa-specific reviews. Further, I developed new methods to quantify trends over space and time in resource status and fishery development. Since 1950, global invertebrate catches increased six-fold with 1.5 times more countries fishing and double the taxa reported. By 2004, 31% of fisheries were over-exploited, collapsed, or closed. New fisheries developed increasingly rapidly, with a decrease of six years (± three years) in time from start to peak from 1960 to 1990. Moreover, 71% of invertebrate taxa (53% of catches) are harvested with habitat-destructive gear, and many provide important ecosystem functions including habitat, filtration, and grazing. For sea cucumber fisheries, global catch and value has increased strongly over the past two to three decades, closely linked to increasing prices and demand on Asian markets. However, the catch of individual fisheries followed a boom-and-bust pattern, declining nearly as quickly as it expanded, and expanding approximately five times as quickly in 1990 compared to 1960. Also, new fisheries expanded increasingly far from their driving market in Asia, and encompassed a global fishery by the 1990s. One-third of sea cucumber fisheries experienced declines in average body size fished; half showed serial exploitation over space by moving further away from the coast; three-quarters showed serial exploitation from high- to low-value species; and two-thirds experienced population declines due to overexploitation with local extirpation in some cases. One-third of all sea cucumber fisheries remain unregulated. These findings suggest that the basis of marine food webs is increasingly exploited with limited stock and ecosystem-impact assessments, and a new management focus is needed to avoid negative consequences for ocean ecosystems and human well-being.

Darbo tikslas – sukurti žvejybos pasiekimų sistemą, kurioje bus kaupiama išsami informacija apie žvejybos vietas ir laimikius. Išnagrinėjus pateiktas žvejybos pasiekimų sistemas pastebėta, kad visos sistemos yra gana panašios: daugelyje kaupiama ir pateikiama informacija, informuojama apie atliekamas funkcijas ir kt., bet juose talpinami laimikiai nėra išsamiai aprašyti. Atsižvelgiant į pastebėtus nagrinėtų sistemų trūkumus, sukurta sistema, kurioje galima rasti išsamią informaciją apie įvairiomis oro sąlygomis ir įvairiuose vandens telkiniuose su skirtinga žvejybos įranga ir masalu sugautas žuvis; vartotojų pateiktas fotografijas galima vertinti balais, rašyti komentarus, filtruoti įrašus ir kt. Naujai sukurta sistema galės naudotis ne tik žvejai mėgėjai ar patyrę profesionalai: patarimų apie įrankius, žuvų gaudymą, masalą ir kt. ras visi, besidomintieji žvejyba. / Aim of the work – to develop the system for the fishing achievements, where information about fishing places and catches will be collected. Analysis of presented systems of the fishing achievements revealed that all systems were rather similar: the majority collects and presents information, explains the performed functions and etc.; however, catches are not described. According to disadvantages of analysed systems, the system has been developed where a person can find all information about catches in different waters, under various weather conditions by applying distinct fishing equipment and baits; photos, presented by users of the system can be evaluated by points, commented, filtered and etc. The newly developed system will be available for all fishermen: amateurs and professionals. Useful advice about fishing equipment, fishing, baits and etc. will be accessible to everybody, interested in fishing.

Pre-copulatory sexual cannibalism (pre-SC), or predation of a potential mate before sperm transfer, provides an ideal model system for behavioral ecology's current focus on inter-sexual conflict. Studying the North American fishing spider (Dolomedes triton), I tested three female-benefit hypotheses for pre-SC: indirect benefits, direct benefits, and aggressive spillover. First, pre-SC may reflect a mating bias providing females with 'good-genes' benefits. By manipulating each female's options with regard to the most cited phenotypic advantage in male spiders, body size, I show that while females exhibit no bias in their attack tendency on males of different body sizes, large males mate significantly more often than small males. Second, pre-SC may be explained by direct benefits if females use it as an adaptive foraging/mating trade-off. My work provides mixed support for this idea: (i) females vary attacks according to the availability of mates, (ii) females do not vary attacks according to the availability of food, and (iii) females derive discrete fecundity benefits from consuming a male. Finally, I tested the aggressive-spillover hypothesis, which posits that pre-SC is a by-product of selection for high levels of aggression towards prey in traditional foraging contexts. Path analysis indicated intra-individual, positive correlations between aggression in foraging contexts and the mating context, thus supporting the hypothesis. I conclude by stressing that pre-SC in a given species may rarely be explained by one hypothesis, and that studies accounting for multiple benefits that fluctuate as behavioral-ecological contexts shift should give a more realistic glimpse of behavioral ecology and evolution.

In the last decade of the 20th Century Somalia made the headlines around the world as the place where a UN force had been withdrawn from due to losses inflicted on US and other troops by members of groups associated with two warlords. In the latter part of the first decade of the 21st Century Somalia was again in the global headlines, but this time associated with acts of piracy committed off its coastline. Behind these headlines lay a complex mixture of problems stretching back as far as the early colonisation of the lands that became Somalia and populated with western European concepts ill suited to the peoples of those lands. The loss of effective government opened the door to neo colonial issues of illegal fishing and hazardous waste dumping that contributed to the piracy problem. Finely interwoven amongst all these issues runs a thread of international law. This thesis examines that thread as it runs through the concept of state failure and asks if it is a legal term and what legal consequences, if any, are attached to it. It examines the international legal frameworks that support fishing and hazardous waste dumping and seeks to understand why they have not prevented illegal fishing and the illegal dumping of hazardous waste off the coast of Somalia. This thesis then examines the concept of piracy as applied to Somalian pirates and seeks answers to questions as to what it is and how it has been applied. It looks at the use of private security as a response and seeks to find the legitimation for their actions in relation to pirates. Sewn throughout is a comparison of responses and suggestions for improvement to international law.

Nutrient inflows from anthropogenic sources into water systems are causing eutrophication, algal blooms and trophic changes in Swedish lakes and seas. The European water framework directive was implemented to regulate member countries' policies to achieve a good status in surface waters. Reduction fishing has shown to be an effective lake restoration tool involving removal of large quantities of planktivorous fish, decreasing the internal nutrient loads and recovering the lake status. The Administrative board of Östergötland (Länsstyrelsen Östergötland) started this project with the aims to find out how to dispose of the fish from reduction fishing projects in a sustainable way in the county of Östergötland. With analysis of secondary lake data, the study also aims to highlight the ecological and chemical status in five of the county's most eutrophic lakes: Asplången, Värnässjön, Svinstadsjön, Nimmern and Hällerstadsjön. The amount of predicted catch during a reduction project, for each lake with the corresponding amount of phosphorus (P) and nitrogen (N) removal, was calculated based on lake area and reduction fishing guidelines. To find out the prospects and possibilities fora sustainable catch disposal, literature review, interviews and communication with possible stakeholders in the area were conducted and analysed in a SWOT-analysis (Strengths, Weaknesses, Opportunities, Threats) as wellas for three sustainability criteria based on the Swedish waste regulation. The results showed that the ecological status is ranging from bad to moderate in the five studied lakes and that approximately 162 - 218 tonnes of fishcould be removed which corresponds to a reduction of P by ca. 1.1 - 1.5 tonnes and N by ca. 4.4 - 5.9. Four possible disposal methods were determined: the use of bream and roach as food for humans, for animal feed, for production of biogas and waste disposal by incineration. Roach and bream for human consumption showed to be a possible option despite a huge resistance in acceptance of roach and bream as edible fishes. Fish as feed was also possible if used as bait for fishing. Biogas production from fish worked well at the local biogas plant as long as the fish was prepared in the right way. Incineration could work as an easy way to dispose off the fish. The SWOT-analysis showed most strengths and possibilities for the biogas option, whereas the food alternative had more weaknesses and threats. However, due to waste management regulations, the use of roach and bream as food or animal feed were the more sustainable options.

Baigiamajame magistriniame darbe „Medžioklė ir žvejybos išteklių apsaugos ir valdymo vertinimas“ buvo išsikeltas tikslas išanalizuoti ir įvertinti medžioklės ir žvejybos išteklių apsaugą bei valdymą. Darbe nagrinėjamos šiuo metų aktualiausios problemos bei gerosios patirtys, savybės teisės aktai žūklės ir medžioklės srityse. Atskleidžiami gyvosios gamtos kontrolės trūkumai. Kad nustatyti visuomenės, žvejų mėgėjų ir medžiotojų požiūrį į dabartinę valdymo sistemą buvo atlikta visuomenės apklausa, kurioje dalyvavo per septyniasdešimt žvejų mėgėjų ir medžiotojų. Darbo eigoje be tyrimo buvo analizuojama su žūklės ir medžioklės sritimi susijusi mokslinė literatūra, regionų aplinkos apsaugos departamentų veiklos ataskaitos, įstatyminiai aktai, valstybinių auditų ataskaitos. Darbas susideda iš, keturių pagrindinių skyrių, išvadų ir rekomendacijų. Iš principo darbą galima suskirstyti į dvi dalis pirmoji supažindina su medžioklės ir žūklės istorija, šiuo metu galiojančiomis tendencijomis, teisės aktais, atliekamais išteklių tyrimais ir jų reglamentavimu. Antroji darbo dalis atkleidžia žūklės ir medžioklės valdymo ir administravimo trūkumus, žvejų mėgėjų ir medžiotojų nuomonę bei pasiūlymus apie šios srities valdymo klausimus ir analizuojamos medžioklės ir žvejybos kertinės problemos. Atlikus tyrimą nustatyta, kad iškelta hipotezė „medžioklės ir žvejybos išteklių valdymas yra neefektyvus“ iš esmės yra teisinga. Nustatyti trūkumai medžioklės ir žvejybos valdymo, priežiūros ir... [toliau žr. visą tekstą] / In the master thesis “Hunting and fishing recourses security and management evaluation” was elevated the aim to analyze and evaluate security and management of hunting and fishing recourses. In the work analyzing the most topical problems and bests experiences, internals and legislations in the hunting and fishing areas. In the this work reveals disadvantages in the control mechanism of natural nature. For determination opinion of public, fishers and hunters attitudes in fishing and hunting system of management was done public survey in which participated more than seventy people who fishing or hunting. In the process of work was analyzed scientific literature, EPA reports about their job, legislation acts, reports of audits which is related with fishing and hunting sphere. Work consists with four basic topics, conclusions and recommendations. In principal this work could be split in two parts from which firs part speaks about hunting and fishing history, tendencies of our days, legislation acts, researches of resources and regulations. The second part of this work reveals disadvantages in fishing and hunting are which consists with management and regulations, fishers and hunters opinion and offers about this field of management. Also in this work was analyzed biggest problems hunting and fishing field. After research was approved the hypothesis “management of hunting and fishing recourses in not effective”. Disadvantages was identified in fishing and hunting... [to full text]

The aim of this thesis is to develop empirical models of the stable catch of brook trout in the Laurentian lakes of Quebec. Current estimators of fish yield are biased and predict poorly. / A model resulting from this study shows that catch increases with fishing effort, but that the rate of increase is smaller at higher effort. For a given effort, the catch-per-unit of effort (CPUE) is greater in larger lakes. Catch is also greater in phosphorus rich lakes and smaller in acid lakes. Catch of bigger fish is associated with a lower CPUE. / No dome-shaped relationship between catch and effort, standardized for the effects of lakes characteristics, could be established. Thus the maximum sustainable yield (MSY) concept provides no guidelines for management of the fishery. However, an early warning of overexploitation is an exceptionally high rate of fishing success. In addition logistic regression based on easily obtained variables can predict the likelihood of stability of the fisheries.

As a highly targeted species, red snapper have been overfished since the 1970’s. Inadequate monitoring and reporting of discard rates impedes regulatory measures which are in place to allow red snapper populations to reach a healthy, sustainable level. This study documented the relationship between morphometric measurements and otolith analysis of red snapper caught from a recreational headboat fishing exclusively in the GOM’s EEZ of the upper Texas coast. The collected data of this research show that of the 594 red snapper caught within the sample group, 76% of the fish were discarded; analysis of the lengths of these discarded fish show that 15.5% were of regulation size (16 inches) or larger, clear evidence that high-grading is occurring. The effort for the total amount of red snapper caught by each individual angler within the sample group was measured to determine on average, approximately two red snapper were caught per person, per hour. The size distribution ranged from 16 to 32 inches with a mean total length of 21.32 inches for retained fish while discarded fish ranged from 5.5 to 22.5 inches with a mean of 14.23. Weight distribution ranged from 1.5 to 18.5 pounds with a mean of 5.81 pounds for retained fish and 0.20 to 6 pounds with a mean of 1.57 pounds for discarded fish. Age distribution ranged from 3 to 14 years of age; red snapper can live over 50 years, however relatively none (2.42%) older than 10 years were present in the sample, demonstrating a highly truncated population. Because fecundancy increases with age in females, longevity extends reproduction potential for red snapper. Management of reef fishes, and red snapper in particular, are difficult due to variances in growth rates and habitat use, complex population structure, and increasing reproduction levels with maturity. Recommendations for management include implementing an educational outreach program, reducing effort and discard rates, lowing rates of exploitation, and creating a marine reserve. Future research should address the entire Texas coast population of for-hire vessels (charter and headboats) to obtain data on discard rates and age distribution of red snapper.

Das Sächsische Landesamt für Umwelt, Landwirtschaft und Geologie analysiert seit 1992 jährlich die Schadstoffbelastung der Fische in den sächsischen Fließgewässern. Im Herbst 2010 wurden jeweils 20 Fische aus der Zwickauer und Freiberger Mulde sowie 100 Fische aus der Elbe entnommen. Trotz des höheren Lebensalters der untersuchten Fische im Vergleich zu den Vorjahren waren die Schadstoffkonzentrationen nicht oder nur wenig erhöht. Zu Überschreitungen der zulässigen Höchstwerte kommt es nur in Ausnahmefällen - das betrifft besonders große und damit ältere Exemplare der Fischarten Rapfen, Zander, Barbe und Döbel. Bei älteren Rapfen gemessene Quecksilberkonzentrationen überschritten beispielsweise die zulässige Höchstmenge teilweise um das Doppelte. Ebenfalls untersuchte Lebern von 19 größeren Fischen wiesen in der Mehrzahl zu hohe Werte an Dichlordiphenyltrichlorethan und Hexachlorbenzol auf. Die Messergebnisse bei anderen chlorierten Kohlenwasserstoffen und Cadmium lagen dagegen wie schon in den zurückliegenden Jahren auf niedrigem Niveau.