An age-structured bioeconomic model, which is completely continuous in age and time, is developed in order to compare with traditional discrete models. Both types have advantages and disadvantages. The continuous framework complements discrete models as it allows for deeper and more transparent analytical study and leads to analytical results that would be difficult to achieve within a discrete framework. To make the model realistic, a nonlinear recruitment function is introduced and steady state solutions and constant-effort optimal fishing are studied analytically. In addition, the framework has been used for numerical analysis. Simulations are used to investigate how optimal harvesting patterns vary with parameter values.
Globalization is characterized not only by economic growth and prosperity but also by increasing pressure on natural resources, unsustainable patterns of consumption and production and increasing inequality. To study these global challenges and their impact on development processes authors identified modern trends in the field of bioeconomy and biotechnology developments, analyzed the main government programs, strategies, funds and statistical information from open sources. The basic principles of bioeconomy methods in agro, food and food security in European countries and in Russian Federation were determined and Genetic engineered organisms statistic, policy and public attitudes from open sources in Russia and European countries were compared
We model the evolution of a trans-boundary marine fishery, which is based on the harvesting of a single “highly-migratory” stock and is beginning to be impacted by regional oceanic-climate changes. The fish-stock’s range will be composed of a number of jurisdictional zones: namely, its intersection with the EEZ of each coastal country for which that intersection is non-trivial. There may also be a zone within international waters of the high seas. We also assume that management of the fishery is vested in a Regional Fishery Management Organization, whose members are countries that are “direct stakeholders” in the fishery—being either one of the above countries with jurisdictional authority in a zone or a country that has registered fishing vessels that are licensed to harvest in the fishery, or both.
A pedigree of a purebred German Shepherd born during the Leningrad blockade was accidentally discovered amidst office waste — and now lies safely stored in a state archive. Our study of the interspecies relationships forged between humans and service dogs in the hardship of blockade and war begins with this document. The story of the several hundred large dogs that survived the Leningrad blockade has long remained untold: the dogs’ survival seemed unethical in relation to the memory of people who died of starvation. These pedigreed dogs were collected from the civilian population in the fall of 1941 and survived the first and second blockade winters in a military engineering unit where they and their handlers were trained to detect hidden explosives. Our article opens a new history of these mine-dog units that quickly became famous on the Leningrad front. It is known that the soviet theory of dog training was based on the “scientifically-objective theory of reflexes.” We show the practical side of this method: the use of service dogs for military aims rested, we argue, on the personal affectionate bonds formed between dog and handler. While formally remaining a military technology, mine-detection dogs acted as humans’ trusted partners and independent historical actors. We show how the centralized Stalinist system, without invading intimate personal realms of interspecies affection, nevertheless planned for and encouraged such affectionate ties in state institutions, where most everything was subordinated to ideological influence: most everything, except the innate species-specific behavior of the dogs themselves.