Adaptations
Many of the fish have made some biological adaptations over their generations. Some common ones are the fish' scales, lined with a mucas that protects the fish from harmful bacteria and toxins. The mucas also helps insulate some heat that is needed for the harsh winters. Also, fish cant just breathe underwater, so at one point or another the fish had to grow gills in order to absorb oxygen from the water. Also the species that must lay eggs near the shores must have strong fins so they can can maneuver away from land predators looking for food near the shores.
Introduced Species
There are over 100 introduced/invasive species in Lake Superior. Our three will all be invasive. First we have the Zebra Muscles (as shown in picture), these were brought to Lake Superior by the ballast water in ships. they settle in dense colonies and can clog intake pipes in the lakes. The second one is the Round Goby. These were also introduced by the ballast water in ships. They out-compete most native species in the lake and as a result reduce the Smallmouth Bass population. The last is the Spiny Water Flea, this species was introduced int 1984. It is found throughout the lakes. It reduces the plankton population which in turn disrupts the entire food chain.