The OED defines an elder, simply, as the senior of two or more individuals - no age specified. 'Elder', as an adjective, conveys the same meaning. This is an interesting question. There are no standard industry answers, just as there isn't a standard label (senior, senior citizen, elderly, old, 65+, etc.)
Bake the trout for 10 minutes, then unfold the packet far enough to check the doneness. When done, trout is moist and flaky with an opaque appearance. Return the fish to the oven and continue baking if necessary. Trout usually cooks within 20 minutes, but may require up to 30 minutes, depending on the size of the fish.
Drizzle the lake trout fillets with olive oil. Sprinkle the fish with the salt, pepper, garlic powder and chili powder. Place the fish fillets, skin side down, on the hot grill and leave them alone for five minutes. Flip the fish over gently and cook for four minutes on the other side.