Search results for " Strategy"
showing 10 items of 764 documents
Integrating fishing spatial patterns and strategies to improve high sea fisheries management
2018
Fishing activity in waters beyond national jurisdiction generates multiple management issues, such as data poor fisheries, management of straddling fish stocks and lack of impact assessments on deep-sea Vulnerable Marine Ecosystems (VMEs). Fishing strategy is the key to understanding and managing high seas fisheries, targeting highly migratory resources that are widely distributed. An international fleet, including Spanish flag bottom trawlers, operates along the Patagonian shelf in Southwest Atlantic waters, which includes an unregulated strip of continental shelf beyond national jurisdiction. The Spanish fleet’s fishing strategy was analyzed, and based on on-board observer data collected …
Multiple‐batch spawning as a bet‐hedging strategy in highly stochastic environments: An exploratory analysis of Atlantic cod
2021
Stochastic environments shape life‐history traits and can promote selection for risk‐spreading strategies, such as bet‐hedging. Although the strategy has often been hypothesised to exist for various species, empirical tests providing firm evidence have been rare, mainly due to the challenge in tracking fitness across generations. Here, we take a ‘proof of principle’ approach to explore whether the reproductive strategy of multiple‐batch spawning constitutes a bet‐hedging. We used Atlantic cod (Gadus morhua) as the study species and parameterised an eco‐evolutionary model, using empirical data on size‐related reproductive and survival traits. To evaluate the fitness benefits of multiple‐batc…
Aeration control in membrane bioreactor for sustainable environmental footprint
2020
In this study different scenarios were scrutinized to minimize the energy consumption of a membrane bioreactor system for wastewater treatment. Open-loop and closed-loop scenarios were investigated by two-step cascade control strategies based on dissolved oxygen, ammonia and nitrite concentrations. An integrated MBR model which includes also the greenhouse gas formation/emission processes was applied. A substantial energy consumption reduction was obtained for the closed-loop scenarios (32% for Scenario 1 and 82% for Scenario 2). The air flow control based on both ammonia and nitrite concentrations within the aerobic reactor (Scenario 2) provided excellent results in terms of reduction of o…
Management strategy analysis for multispecies fisheries, including technical interactions and human behavior in modelling management decisions and fi…
2018
A multispecies fishery management strategy evaluation (MSE) framework based on the example of the groundfish fishery in the Bering Sea and Aleutian Islands region of Alaska was used to examine the interplay between a bycatch species and three groundfish species. The study introduces a framework for a realistic multispecies fishery MSE by accounting for fleet dynamics, multispecies fishery quota allocation, and the temporal dynamics of technical interactions. The quota allocation and the fleet dynamics models were implemented using linear programming, and regression approaches were used to make a realistic projection of future users’ behavioral response to changes in the fishery. The models…
Early ontogeny defines the diversification of primary vascular bundle systems in angiosperms
2020
AbstractUnderstanding vascular bundle systems in angiosperms is a challenge. On the one hand, the vascular tissue is extremely important in reconstructing the evolution and survivability of plants, but on the other hand, it forms a complicated three-dimensional system of controversially discussed phylogenetic and ontogenetic origin. To increase clarity, in this paper we briefly summarize histological, phylogenetic and molecular aspects of primary vascular bundle formation in angiosperms, adding histological data on early stages of vascular bundle formation, proposing a concept combining the different views and providing simplified illustrations to improve the understanding of primary vascul…
Preface: Emerging trends in aquatic ecology II
2017
You are now consulting the celebratory volume 750 of Hydrobiologia, the international journal of aquatic sciences. The journal has, since its first volume in March 1948, now exactly 67 years ago, covered a lot of ground and has seen a lot of change in the landscape of scientific publishing in general, and in that of aquatic biodiversity in particular. It has evolved from a fairly locally managed journal, to an international journal with ever increasing impact and ranking. With an ISI 2013 Impact Factor of 2.212, it now ranks 32 out of 103 journals in ‘‘Marine and Freshwater Biology’’. But in the ‘‘Marine Sciences and Fisheries’’ Category of Google Scholar, Hydrobiologia ranks proudly at a 9…
Does evolution of iteroparous and semelparous reproduction call for spatially structured systems?
2000
A persistent question in the evolution of life histories is the fitness trade-off between reproducing only once (semelparity) in a lifetime or reproducing repeated times in different seasons (iteroparity). The problem can be formulated into a research agenda by assuming that one reproductive strategy is resident (has already evolved) and by asking whether invasion (evolution) of an alternative reproductive strategy is possible. For a spatially nonstructured system, Bulmer (1994) derived the relationship v + PA1 (PA is adult survival; vbS and bS are offspring numbers for iteroparous and semelparous breeding strategies, respectively) at which semelparous population cannot be invaded by an ite…
Interannual variation and long-term trends in proportions of resident individuals in partially migratory birds
2016
Partial migration - a part of a population migrates and another part stays resident year-round on the breeding site - is probably the most common type of migration in the animal kingdom, yet it has only lately garnered more attention. Theoretical studies indicate that in partially migratory populations, the proportion of resident individuals (PoR) should increase in high latitudes in response to the warming climate, but empirical evidence exists for few species. We provide the first comprehensive overview of the environmental factors affecting PoR and the long-term trends in PoR by studying 27 common partially migratory bird species in Finland. The annual PoR values were calculated by divid…
Antarctic and Sub-Antarctic Asteroidea database
2018
The present dataset is a compilation of georeferenced occurrences of asteroids (Echinodermata: Asteroidea) in the Southern Ocean. Occurrence data south of 45°S latitude were mined from various sources together with information regarding the taxonomy, the sampling source and sampling sites when available. Records from 1872 to 2016 were thoroughly checked to ensure the quality of a dataset that reaches a total of 13,840 occurrences from 4,580 unique sampling events. Information regarding the reproductive strategy (brooders vs. broadcasters) of 63 species is also made available. This dataset represents the most exhaustive occurrence database on Antarctic and Sub-Antarctic asteroids.
Active Wild Food Practices among Culturally Diverse Groups in the 21st Century across Latgale, Latvia
2021
Simple Summary A study in the bordering region of Latvia took place in order to investigate wild plant food uses. In total 72 interviewees reported food uses. The most represented uses of recorded plants were recreational tea; for jam; as snacks and soup; and drink. Interviewees also reported loss of foraging practice due to the habitat change as for example in case of caraway and chamomile. The results indicated that part of the reason for the main use of wild plants were linked to diet diversification. Abstract Local ecological knowledge (LEK), including but not limited to the use of wild food plants, plays a large role in sustainable natural resource management schemes, primarily due to …