Bone deformities occur regularly in fish farms around the world. The operculum is one of the earliest craniofacial bones to form embryologically and is subject to a range of developmental and acquired abnormalities. Opercular shortening is one of the most prevalent diseases in larval and juvenile salmonids (and other species), sometimes affecting up to 80% of fish in a population. In those species that rely on the operculum to help move water over the gills, loss of efficiency in this part of the pumping mechanism...
![Figure 1. Severe opercular erosion in farmed rainbow trout.](https://sp-ao.shortpixel.ai/client/to_webp,q_glossy,ret_img,w_700,h_447/https://fishhistopathology.com/wp-content/uploads/2020/03/Fig-14.2B.jpg)