Turkey's Sea of Marmara is on the brink of environmental collapse. Pollution, overfishing and climate change are depleting its oxygen. The crisis became visible when a thick layer of algal slime first began spreading across its waters in 2021. Necla Köseoğlu, from Rumelikavağı, is one of the last people still working in traditional small-scale fishing on Turkey's Sea of Marmara. She's also one of the few women in the business. She used to be able to live off what she made from fishing, but those days are gone. Fish stocks in the Turkish inland sea have declined dramatically. The ecosystem is at risk of collapse due to overfishing, urban and industrial waste, and shipping pollution. The Marmara Sea, whose shores are home to around 25 million people, is suffocating.