Dalyan means "fishing weir" in Turkish.
Bass, Mullet and Sea Bream swim upstream from the sea to Köyceğiz Lake where another large town of the region, Köyceğiz, is located.
The fish spawn there, and when returning to the sea they are caught in the "dalyans".
According to the turkish etymological dictionary Nisanyan Sözlük, dalyan (ta aliana) derives from the greek word aliia (αλιεία) which means fishing.

<https://www.nisanyansozluk.com/?k=dalyan>
Dalyan means "fishing weir" in Turkish. Bass, Mullet and Sea Bream swim upstream from the sea to Köyceğiz Lake where another large town of the region, Köyceğiz, is located. The fish spawn there, and when returning to the sea they are caught in the "dalyans". According to the turkish etymological dictionary Nisanyan Sözlük, dalyan (ta aliana) derives from the greek word aliia (αλιεία) which means fishing. 
<https://www.nisanyansozluk.com/?k=dalyan>
Dalyan