branchial

https://doi.org/10.1351/goldbook.10471

Of, relating to, or resembling the gills of a fish or the homologous embryonic structures and their derivatives in higher animals.

Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 731 (https://doi.org/10.1515/pac-2015-1202)