Scores of starfish, both dead and alive, have washed ashore the coasts of Turkey's Marmara Sea in the northwestern province of Tekirdağ, while the provincial environment directorate has said an investigation has been launched to determine the cause of the incident.

Locals saw hundreds of starfish emanating a "bad odor" on a sandy beach in the Kumbağ neighborhood of Tekirdağ's Süleymanpaşa district at mid-day on June 27.

While some residents threw the starfish back into the sea in an attempt to save their lives, others collected the animals for decorative purposes.

"We come here during the summer months. I have never seen anything like this. Many starfish hit the beach," Didem Deniz, a vacationer, told reporters.

"We were curious and searched online. We found out that they can commit mass suicide. Some even moved," Deniz said, adding a "bad odor" was coming from the masses of starfish.

Meanwhile, the provincial head of Tekirdağ's Environment and Social Planning Directorate, Ömer Albayrak, said an investigation had been launched into the incident.

Albayrak underlined that they collaborated with the Public Health Directorate to take sea water samples every 15 days to be tested at a hygiene institute in Istanbul, the Hıfzıssıhha.

"We will still conduct an investigation in the area. We will see whether something is polluting the sea," he added.