This isn't quite exact, but 1/4 cup of butter (so a half stick if you're in the US) is 57 grams according to the conversion chart from allrecipes below. So use just a slightly heavy 1/4 cup or 1/2 stick.
Yellowtail, including Yellowtail Jack (Seriol landei), are recognized by a yellow stripe across their body and their yellow tail. Range & Habitat: Yellowtail is caught year round, but more commonly during summer in the Pacific Coast and the Sea of Cortez. They are caught primarily with hook and line, and their average weight is 10 to 20 lbs.
Yellowfin is a species of tuna that is found in the Gulf of Mexico and the Atlantic and Pacific Oceans. The scientific name for the yellowfin tuna is Thunnus albacores. Other names for yellowfin tuna include ahi and Allison tuna. Although the average yellowfin tuna weighs 80 pounds, they can weigh up to 400 pounds. Yellowfin tuna is a low-calorie and low-cholesterol protein source. Video of the Day