Metallothionein, oxidative stress and trace metals in gills and liver of demersal and pelagic fish species from Kuwaits’ marine area

•Seabream and tonguesole were collected from Kuwait Bay and outside the Bay area.•Hepatic metallothionein in fish and metals in sediment were higher in Kuwait Bay.•Pelagic and demersal fish showed differences in tissue metals and metallothionein.•Metallothionein was associated with metals and antioxidant enzymes in fish tissue.•An association was found between metals in sediment, fish liver and condition index.