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.
Tail Length: 50 cm / 20 in. Weight: 600-1000 kg / 1320-2200 lb. The smooth coat is beige to light brown in wild-type individuals, with the undersides slightly lighter. However, selective breeding has also produced forms that vary from dark brown to white.