Gallery 3.3: Identifying Damaged or Frozen Fish

Faded markings: sometimes the lines and other markings on the sides of the fish can fade, preventing species identification using that characteristic. Here the yellowfin (top) retains some of its vertical markings below the lateral line, however the…

Faded colors: sometimes the fish’s coloring can be faded, preventing species identification using that characteristic (yellowfin top, bigeye bottom). The colors can fade entirely to silver/white and blue/black, but body shapes should still allow ide…

Predation (e.g., shark bites), net damage, or other handling damage can also make species identification difficult. In this case, the intact pectoral fin (long, with a thin and flexible tip) suggests bigeye as the species. (Photo: David Itano)

Deck spill on a purse seine vessel. The observer must be aware of general species and size composition as the tuna come on board—and to note changes in those variables as the catch is brailed. (Photo: David Itano)

Brine-frozen tunas will likely be entirely absent of distinguishing color characteristics, and distortion of body shape is more likely. (Photo: David Itano)