BY ANNELIESE MOLL
For the UAS Whalesong
Invasive species are everywhere. They can be plants, fungi, pathogen, or an animal species that is not native to a specific area. These invaders can often spread to a level that can greatly impact the lives of the native species, who often cannot out compete them. Within Alaska there are many invasive species ranging from plants to animals and insects to many marine organisms.
Elodea is an underwater perennial that has the ability to form large tangled masses within bodies of freshwater. In 2010, Elodea was discovered in Chena Slough in Fairbanks. This eventually brought attention to the established population in Eyak Lake along with several other water bodies in four regions of the state. This plant is particularly hard to get rid of because it can form entirely new plants out of the broken stem fragments.
Atlantic Salmon (Salmo salar) are anadromous, meaning like other salmon species, they spend time in freshwater for the first part of their life before going out to sea for the last couple of years. However, unlike Pacific salmon, if the Atlantic salmon does not necessarily die after spawning. These fish have the potential to negatively impact Alaska’s native salmon and trout because they would compete for spawning habitat. It’s been recorded that juvenile Atlantic salmon are more aggressive than Pacific salmon, which would easily enable them to outcompete the Pacific salmon for recourses. Atlantic salmon are also bred and raised in highly overpopulated pens and treated for disease and parasites. While fish may not show the signs of being unhealthy, they can carry diseases which could also have large negative impacts on Pacific salmon.
Another marine species with huge negative impacts is the Didemnum vexillum, which is a marine colonial tunicate. What makes this one so awful is that it is a “carpet tunicate” which has the ability to completely cover marine ecosystems. This tunicate is also fast growing and when broken, each piece broken off can become the start of a new colony. D. Vex, as it’s commonly being called, is an ecosystem engineer, and as you imagine due to it’s nature it negatively impacts any ecosystem it is brought into because it can effectively grow over any surface and cover any organisms unable to move out of its way.
Alaska also has an invasive insect: the gypsy moth (Lymantria dispar). Females are larger than the males with a wingspan of around 2.5 inches. They are almost all white with several dark markings on their wings. Males are a light brown with darker down sections on their wings. The males also have a wingspan of under 2 inches. Recently hatched larvae black and hairy. Less recently hatched develop a mottled yellow-gray pattern with tufts of stiff hairs and two rows of blue and red spots along the back. Before their metamorphosis, the larvae are around 2–2.5 inches long. When their populations are small, these moths are not necessarily the worst species to deal with. However, when there are large outbreaks, the larvae can completely strip trees of their leaves, which can result in the death of the host tree. Unfortunately, such outbreaks can last up to 5 years. Ultimately, this can impact ecosystems because it changes the available recourses.
The Norway rat is also highly invasive. Their wide diet range and adaptability allow them to do well almost everywhere. Within Alaska, rats can have strong negative impacts on sea bird nesting colonies. Examples of this can be seen in some of the Aleutians. One island is actually known as “Rat Island” because of the extent of the rodent infestation that was a result of a shipwreck. That island had once been a large bird nesting colony, but has declined significantly because of the rats. From 2007 to 2009, there was an eradication program set in place and the result was an increase in the bird populations. Rats can also carry many disease and parasites, which can also present other problems to native populations.
With summer quickly approaching, it may seem like a waste of time to pull weeds off of a boat or cruel that you cannot release a pet into the wild, but it is important to remove plant matter and to not release your pets because, if we do not take care of our environment, invasive species can spread quickly and become very difficult to remove once even slightly established.
There are many online resources when it comes to reporting, identifying, and dealing with invasive species. The Alaska Department of Fish and Game is highly involved and wants people to contact them with information regarding new species.
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