noun
dogtooth tuna
A species of tuna (Gymnosarda unicolor) found in tropical and subtropical waters. In Japanese, it is a specific fish name, not a general term for tuna.
イソマグロはマグロの一種で、歯が鋭い。
The dogtooth tuna is a type of tuna with sharp teeth.
マグロ is the general term for tuna, while イソマグロ refers specifically to the dogtooth tuna species.
Compound of 磯 (iso, 'rocky shore') and 鮪 (maguro, 'tuna'), referring to a tuna often found near reefs.