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Citizen Science
and the Marmara Sea
Funded by the National Geographic Society
May 2025 Observations
Every month, our community of citizen scientists submit reports about the Marmara Sea. From jellyfish sightings to pollution and mucilage outbreaks.
May 2025 Reports: 38
Total Reports Collected: 135
Jellyfish Sightings
26% (10/38)
Mucilage Reports 16% (6/38)
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Pollution Sightings 47% (18/38)
Jellyfish
10 jellyfish sightings were reported in May, with the most common species being Moon Jellyfish and Compass Jellyfish. Observations came from both shoreline and open water, often in small clusters. Small jellyfish often indicate the presence of juvenile medusae—young jellyfish in their early life stage. April through May marks their peak hatching season, so sightings during this time are expected. Their numbers can reflect natural breeding patterns or, in some cases, ecological imbalances triggered by warmer temperatures and nutrient-rich waters.
Mucilage
Mucilage reports from May noted the presence of flake-type clusters near the shoreline—thin, early-stage formations commonly seen before a full bloom. Flocs (also called flakes) are among the earliest visible signs of mucilage formation. These small, thread-like clusters of phytoplankton often signal the beginning of a potential bloom. If conditions remain favorable—such as stagnant waters and nutrient buildup—these flakes can rapidly grow into thick, sponge-like mats that stretch from the sea surface to the seafloor, threatening marine life and water quality.
Plastic
18 reports across the Marmara region included observations of plastic pollution, both in the sea and across the shoreline, divided into Microplastics, Macroplastics and unidentifiable waste. Plastic pollution poses one of the most persistent threats to the Marmara Sea. Regular community reporting not only maps pollution hotspots—it also helps us track trends, identify sources, and push for targeted cleanups and policy change.
Sighting Locations
Bebek
Beşiktaş
Beykoz
Beylerbeyi
Beylikdüzü
Büyükçekmece
Darıca/Kocaeli
Halil
Maltepe
Mudanya
Rumeli Hisarı
Mudanya had the highest number of reports this month.
45% of all observations came from this coastal town—making it a critical watchpoint for future marine activity.