In this study, 12 taxa from the Chlorophyta, Phaeophyta and Rhodophyta were collected from different depths at Gemlik-Karacaali and Erdek-Ormanl?. A total of 175 specimens from these divisions were used to determine Total Protein (TP), Total Soluble Carbohydrate (TSCH) and Chlorophyll a (Chl a), Chlorophyll b (Chl b), Chlorophyll c (Chl c), total carotenoid (Car) contents and Chl b / Chl a, Chl c / Chl a, Car / Chl a, Car / Chl b, Car / Chl c ratios. TP, TSCH and pigment contents varied significantly with respect to the algal taxa, stations and depth distribution. In addition, individual differences were important in all of the measured parameters. The maximum TP contents (0.94%-31.03%) were determined in some of the Rhodophyta. In some green seaweeds belonging to the genus Ulva L., the TP content was determined between 2.9%-28.1%. Lower TP contents were determined in Cystoseira barbata (Good) C. Agardh (1.1%-4.3%). In contrast to TP contents, TSCH values were very low; maximum TSCH were determined in Ulva species, as were protein contents. In conclusion, the variations in TP, TSCH and pigment in 12 taxa of macroalgae were analysed according to station, depth, and environment.