Fig. 6

Shells and samples of the bottom substrate of the bivalve mollusc Mactra chinensis collected during SCUBA diving in Peter the Great Bay (Sea of Japan, Russia). A three samples (1–3) representing collection in the area 1 (see Fig. 5, 1). B three samples (1–3) representing collection in the area 2 (see Fig. 5, 2). C three samples (1–3) representing collection in the area 3 (see Fig. 5, 3). D three samples (1–3) representing collection in the area 4 (see Fig. 5, 4). A′ the pigment colour samples tested in the central shell area (red square) and in the peripheral shell area (yellow square) from the samples A1 (A′-1, 1′), A2 (A′-2, 2′), and A3 (A′-3, 3′). B′ the pigment colour samples tested in the central shell area (red square) and in the peripheral shell area (yellow square) from the samples B1 (B′-1, 1′), B2 (B′-2, 2′), and B3 (B′-3, 3′). C′ the pigment colour samples tested in the central shell area (red square) and in the peripheral shell area (yellow square) from the samples C1 (C′-1, 1′), C2 (C′-2, 2′), and C3 (C′-3, 3′). D′ the pigment colour samples tested in the central shell area (red square) and in the peripheral shell area (yellow square) from the samples D1 (D′-1, 1′), D2 (D′-2, 2′), and D3 (D′-3, 3′). A′′–D′′ the pigment colours that are correspondingly typical for the collection areas 1–4. A′′′–D′′′ the substrate colours that are correspondingly typical for the collection areas 1–4. Scale bar—1 sm (A–D), (A′′′–D′′′); 0.5 sm (A′–D′); 0.2 sm (A′′–D′′)