Berenshtein, I. | Search bioRxiv

bioRxiv2024

Proposed network of Marine Protected Areas supports larval dispersal and connectivity in the Eastern Mediterranean

The marine environment of the Eastern Mediterranean is under growing threat due to natural and anthropogenic stressors. Networks of Marine Protected Areas (MPAs) are effective tools in protecting marine environments and conserving their biodiversity. Currently, only 4% of the Israeli territorial waters are declared as MPAs, however six new MPAs, which will encompass more than 20% of the Israeli territorial waters, are planned. A central component in the effectiveness of MPAs is the degree to which the protected populations are connected. The purpose of our study is performing a comprehensive connectivity analysis for the proposed network of MPAs. We find that the proposed network substantially supports local and regional larval connectivity patterns for five target species in terms of the number of recruits, betweenness centrality, as well as the number of regional and local MPAs connections. Overall, the results provide strong support for the efficiency of the proposed MPAs in facilitating local and regional larval connectivity. Our findings will be useful for marine spatial planning and natural resource management and will enhance the protection and conservation of our marine environment.

ecology↗

bioRxiv2024

Directional swimming patterns in jellyfish aggregations

Having a profound influence on marine and coastal environments worldwide, jellyfish hold significant scientific, economic, and public interest. The predictability of outbreaks and dispersion of jellyfish is limited by a fundamental gap in our understanding of their movement. Although there is evidence that jellyfish may actively affect their position, the role of active swimming in controlling jellyfish movement, and the characteristics of jellyfish swimming behavior, are not well understood. Consequently, jellyfish are often regarded as passively drifting or randomly moving organisms, both conceptually and in process studies. Here we show that the movement of jellyfish is controlled by distinctly directional swimming patterns, which are oriented against the direction of surface gravity waves. Taking a Lagrangian viewpoint from drone videos that allows the tracking of multiple adjacent jellyfish, and focusing the scyphozoan jellyfish Rhopilema nomadica as a model organism, we show that the behavior of individual jellyfish translates into a synchronized directional swimming of the aggregation as a whole. Numerical simulations show that this counter-wave swimming behavior results in biased correlated random-walk movement patterns that reduce the risk of stranding, thus providing jellyfish with an adaptive advantage critical to their survival. Our results emphasize the importance of active swimming in regulating jellyfish movement, and open the way for a more accurate representation in model studies, thus improving the predictability of jellyfish outbreaks and their dispersion, and contributing to our ability to mitigate their possible impact on coastal infrastructure and populations.

ecology↗