Lemon juice and pepper..,or make your own lemon pepper....salt grated lemon peel a bit of garlic powder, a bit of onion powder adn some celery salt....and black pepper.
Frankly with a nice piece of fresh lake trout I would just dot it with butter, salt lightly and bake until it flakes....then add a generous squeeze of fresh lemon.

You can use white wine in place of lemon juice, or your can sprinkle a few drops of white wine vinegar on it after it is cooked.

How do you plan to cook it? Is it filleted? We often cook fish Cajun style, with Cajun seasoning, and then blackened in butter in a cast iron skillet. You can also deep fry it as tempura and then serve it with tempura sauce or tartar sauce.

I assume you do not have lemons.

I assume you don't have lemons either. I have only had lake trout while back backing so the fish would be super fresh. We just pan fried them in a little oil (if we had it), or bacon grease (from the bacon and pancakes you know), and then just add salt and pepper. By the way, we really like salmon similarly plain with just salt and pepper and perhaps some dill if it is growing in the garden. I always grill the salmon and would likely grill trout filet if I had it.

Thanks! It is filleted. No fresh lemons or limes. Just "Real lemon" in the bottle. I have dried lemon peel but it is rather old. I DO have oranges! If that's useful. No white wine, but I did find white wine vinegar.

DH and I will occasionally pull a nice sea trout out of the Gulf (of Mexico), and we always prepare it blackened (per Lars' suggestion). A basic blackened seasoning blend: paprika, onion powder, garlic powder, sugar, chili powder, salt, black & white peppers, cumin, cayenne, mustard and nutmeg. I always keep ~ 1/4 cup of the mix on hand for whenever a trout might come our way. (Though, I sprinkled a little onto last weekend's baby back ribs, and they were yum!)

I often bake fish with dried dill, capers, black pepper, and butter, but you could also broil it in butter very quickly. I think butter would be enough if you broil it, plus S&P to taste. If you bake it with capers, you won't need salt, as capers are salty enough.

For almost every kind of fish, I like coat fillets with yellow cornmeal mixed w/ tarragon, salt and pepper, then sauteed in butter and olive oil until crispy. If I have any, I'll add some Spike salt-free seasoning too.