Farallon Island Rodenticide Essay
Diphacinone, and it’s Effects on Wildlife and it’s Environment The Farallon Islands aviary wildlife is under attack and something needs to be done about it. The Farallon Islands are a chain of islands about 28 miles west off the coast of San Francisco. They are used by by hundreds of seabirds for feeding, nesting, and breeding. In fact these islands have a greater variety of bird species than almost any other place in the world. The problem is that mice have overrun the island eating the bird eggs and killing the young birds.
Some areas are so densely opulated with mice that the biologists on the island say that sometimes the ground seems to move (Frimrite, Peter 1). There are three suggested solutions to the problem so far. One solution would be to do nothing. Another would be to use a less potent poison such as Diphacinone but distribute it often and for a long period of time. The final option would be to use an extremely potent poison such as Brodifacoum and distribute it for a shorter period of time and less often. In this paper we will look at the second option of using a less potent poison and try and etermine whether this would be the best approach.
First, it is important why the mice are such a problem. One of the many things that the mice have against them is that they are the only nonnative species left on the island. The mice first came when seal hunters first sailed to the islands to hunt the abundance of elephant and harbor seals. The second problem is that the mice are attracted Burrowing Owls to the island. The owls not only eat mice, in the winter when the mouse population drops drastically they turn to their second option, birds. Their favorite bird to snack on the Ashy Storm Petrel which is currently on California’s Endangered Birds list.
Half of the Ashy Storm Petrel’s 8,000 population comes to the Farallons to nest and feed. Another problem the mice are causing is that there eating the insects that the Arboreal Salamander depends on immensely. The final problem is that the mice are spreading a highly invasive plant. The seeds are sticking to their fur coat and spreading it across the island The current deployment plan for the Farallon Islands is to deploy Diphacinone apsules during three air-drops spaced 5 weeks apart. That will keep the archipelago contaminated with the poison for fifteen weeks, ten more weeks than the other more potent poison called Brodifacoum.
The more time the poison is on the island and active the more chance that non-target animals could consume the capsule and die. The question is, how much danger does this pose to the non-target animals? Not much data has been collected about side affects of Diphacinone on birds and marine life. The only concrete data for birds is a test that showed that if a bird eats oughly 2400 milligrams of pure diphacinone capsules they have a 50% chance of fish and other marine life such as crustaceans and shelled mollusks so does not appear to pose a serious risk for these animals (Cornell University 1).
No experiments have been conducted to see if Diphacinone creates any reproductive or genetic problems and therefore it is unknown how future generations might be affected. It is important to mention how Diphacinone will be used to kill the mice. When a mouse eats Diphacinone poison it will take up to 4 to 7 days of continuous feeding to ill the mouse (Dichling Corporation 1). Since it takes so long to kill the mouse the mouse doesn’t make the connection that the poison is killing them and so continues eating the poison.
When the poison enters the mouse’s body it cause severe internal bleeding, it will continue to bleed until dead. A problem arises if the rodent consumes too much of the toxin too quickly and then dies. When this happens the mouse will become a poison hazard to predators in the area. Therefore, if a scavenger happens to find the dead mouse or if a predator eats a live rodent when t’s stomach is full of the poison it would also be contaminated with the Diphacinone .
Animals are not the only ones that are affected by the poisonous capsules, humans can be at risk as well For instance, if a capsule somehow got into the human water or food supply it could lead to serious problems. If someone was to consume the poison the symptoms include back and lower chest pain, bloody gums, nosebleeds, and internal bleeding. In extreme instances eating the rodenticide can lead to the inability for your blood to clot which could lead to death (Cornell University 1). This will not be the first time that poison has been air-dropped onto an island to eliminate a rodent problem.
In 2008 Brodifacoum, the other suggested poison, was used to eliminate the rats on Rat Island, Alaska. In this case many non-target animals were killed and it has taken many years to recover from the incident. Over 40 Bald Eagles were killed in the process of poisoning the island. That’s 20 more eagles than biologists even knew were on the island. On top of the eagle deaths more than 400 other birds fell victim to this poisoning. This was a far larger mortality rate than xpected, and took the biologists by surprise.
Given the facts list above, my opinion is that Diphacinone should not be used to eliminate the rat problem on the Farallon Islands. All though it’s the least potent option all the unknown variables that could cause unnecessary non-target deaths. From the endangerment of endangered spices, the possibility of harming the scientists researching on the archipelago, and the potential of damaging the future generations of bids, fish and other marine life. Poisoning the islands is a bad idea and we should wait until a better solution approaches