Ole Johannes R

   Identifying important habitats associations in the fish community structure, specifically on certain key species. 


Ph.D. candidate 

IntroductionThe fish communities inhabiting the Eastern Mediterranean Sea are subjected to many anthropogenic and climatic stressors, such as rapid temperature rise, fishing activities, introduction of Indo-Pacific species, industrial development, pollution and more. The changes in fish community structure have previously been studied through trawl- and in-situ surveys, but identifying key stressors remain uncertain. The most pressing ones, however, is suggested to be sensitivity to climate change and alien species invasions. Over time, indigenous fish species must either adapt or migrate. One possible adaptation strategy forced on fish species by fisheries is the change of size distributions and timing of sexual maturation. Identifying different habitat requirements throughout the life cycle of different species is therefore pivotal for proper management of key species, e.g., identifying important reproductive aggregation habitats or predatory-prey interactions at certain habitats. As temperatures at the Israeli continental shelf is close to the upper threshold of certain species, the resilience of these species is constantly at the tipping point. Because of this, anthropogenic stressors can greatly affect the fish communities, and a deep understanding of their population dynamics and habitat associations are pivotal for the management and conservation of these fish communities.
The planned research will focus on marine shallow water fish communities in the eastern Mediterranean Sea. The major aim of the research is to identify important habitats associations in the fish community structure, specifically on certain key species. Population dynamics of certain species will be investigated, with particular focus on stressors related to anthropogenic activities. Particularly, the research will aim to identify habitat niches on a high-resolution scale for single species to better understand species distribution in a changing environment. Additionally, as invasive species continue to shape the ecosystem, I intent to dedicate some of the research topic to this effect. By studying current and recent state of the marine fish communities, I aim to build a theoretical framework of possible novel ecosystems. 
The Morris Kahn Marine Research Station under the Leon H. Charney school of marine sciences at the University of Haifa have done extensive fish surveys since 2014 at different rocky reef locations, and their database will be an excellent starting point for coming research questions. I intend to research these important shallow water communities by harmonizing the existing database, using statistical methods to analyze and test the significance of the research variables. Depending on the preliminary research, other biological methods can be implemented to further analyse fish communities, such as stable isotopes, existing fisheries data, meta-data analysis and virtual population analysis. 
Ecological modelling approaches such as Species Distribution Modelling can be an effective tool for identifying species-habitat associations. By incorporating Fisheries biology and ecology with high-level in-situ surveys, I aim to classify differences in habitat associations throughout the life cycle of certain species and the driving factors affecting the fish community. 
 

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