FISH FACTS

FISH FACTS

A: That’s a really nice trevally. It’s definitely a member of the diamond trevally genus, Alectis, but it’s hard to tell whether it’s A. ciliaris (a pennant fish or African pompano) or A. indicus (a diamond trevally or Indian threadfish). Both species can reach at least 48 pounds, and both are found in Australian waters. You can distinguish them only by minor differences in their dorsal-fin rays and by gill-raker counts. If I had to provide an answer using only this image, I’d say it’s A. indicus, based on the shape of its forehead (which is more vertical than in A. ciliaris) and the lack of faint vertical bands on its flanks near the anal fin, which can sometimes persist even in large diamond trevally. Both species’ juveniles have the long, distinctive filaments trailing from dorsal and anal fins that gave the pennant fish its name, and both species lose the filaments as they grow into adulthood. — Ben Diggles

 Q: As an avid fisherman who lives in the Golden Gate area of California, I’m curious what makes the flesh of salmon and steelhead trout orange. Also, why do lingcod and cabezon have bluish-green flesh? I’ve caught all these species and would.

A: The color in salmon and steelhead meat comes from carotenoids, the red pigments found in krill, one of their primary foods. If you feed salmon something that does not contain carotenoids, the muscle appears whitish. However, there is also a genetic component. Some Chinook salmon are white, even though they eat krill. This implies that there has to be a gene that allows the carotenoids to turn the muscle pink or red. The color of cabezon and lingcod is still something of a mystery. It might come from their food — crabs, a major part of the cabezon diet, have blue blood. On the other hand, crabs are not that important to lingcod. Genetics may also play a part, but no one knows for sure. However, with these species, the greenish color cooks out to pure white, and it in no way affects the flavor of the fish; with salmon, the pinkish color remains