Suitability of calcein as an in situ growth marker in burrowing bivalves

►We study the suitability of calcein as in situ growth marker in burrowing bivalves. ►We test how calcein concentration affects marking success and bivalve performance. ►Marking success increases with higher calcein concentrations and decreases with age. ►No detrimental effects are detected when using calcein concentrations ≤ 200 mg l−1. Our in situ marking method seems suitable for growth studies on burrowing bivalves.