By Evan KreagerGreat Lakes EchoAsian carp may be one of the better known of the many aquatic invasive species attempting to make their way into the Great Lakes basin. They are one of the five “usual suspects” recognized by The Nature Conservancy in a public awareness campaign. Big head and silver are the most common types of carp, having been spotted in 18 different states, according to The Nature Conservancy. Big head carp can grow up to 60 inches and weigh over 100 pounds. Silver carp are a bit smaller, with a length of about 40 inches and a weight of 60 pounds.