Gill proteome samples from four populations of threespined sticklebacks; Six biological replicates each for 4 different populations: Bodega Harbor, CA (fully plated, marine), Lake Solano (low-plated, freshwater), Laguna de la Bocana del Rosario, Mexico (low plated, brackish water, warm-adapted), Westchester Lagoon, AK (fully plated, brackish water); More information and results of data analysis at CAMP Proteome, accession number CAMPDDA00023 (https://kueltzlab.ucdavis.edu/CAMP_dda_profiles.cfm?AC=CAMPDDA00023).