Is abalone high in cholesterol?

Same as most animals: The cholesterol content in most animals per unit weight is quite similar. The difference is usually related to their relative content of saturated (like marbled fat in red meat) and polyunsaturated (like omega-3 fats in sea food) that determine their health risks. Abalone likely is very low in saturated fat itself, but like most sea food, gets less healthy with the drawn butter that accompanies it.