Thursday, March 8, 2012

Money Suckers Invade

Invasive species are somewhat of a "soft" ocean issue, which really means that the urgency and immensity of climate change and overfishing generally overshadows it. 

But just look at what's at stake with invasive species, and Atlantic Ocean lampreys in particular.  These suckers are moving into the Great Lakes threatening a $7 billion fishing industry and requiring millions of dollars in preventive measures.  And that's only lampreys.  There are hundreds of invasive species.

Sea Lamprey sucking on a Lake Trout

I'm exhausted just reading these "control techniques" for lampreys.  According to the Ashland Current:

"There are four main techniques used to control sea lampreys: lampricides, barriers, sterile male release, and trapping.

Lampricides, most notably TFM (3-trifluoromethyl-4-nitrophenol), kills sea lamprey larvae in streams and is typically the most effective method used to control sea lamprey in the Great Lakes. Testing since the early 1950s suggests TFM has negligible effects or is completely nontoxic to fish, wildlife, invertebrates, and aquatic plants. In addition, TFM is harmless to humans and other mammals at the applied concentration.

Barriers are created to block sea lampreys from migrating upstream to spawn, while still allowing other fish to pass; velocity barriers prevent passage by taking advantage of the lampreys’ poor swimming ability, electrical barriers use current to repel the sea lampreys during spawning migration, and adjustable-crest barriers are inflated during the spawning season and deflated to allow fish passage throughout the rest of the year.

Sterile male release is the practice of capturing and sterilizing male sea lampreys, then releasing them back into streams to compete with non-sterilized males for spawning females. Females that attempt to breed with sterilized sea lampreys will not become fertilized, and therefore will not produce offspring. Streams that implement sterile male release technique have been known to have significant decreases in sea lamprey population, and are becoming increasingly popular in large waterbodies where lampricide treatment is too expensive.

Traps for sea lampreys are often installed near barriers. Males that are caught are typically sterilized and released following the sterile male release technique, while females are used for research."

And yes, the chemicals used to control lampreys make me uneasy -- how do they impact other marine species?

There is a long list of marine invasive species including lionfish, red algae, and the Asian shore crab. 

Invasive species come from far away places.  They leave their predators behind so in their new environment they enjoy free reign.  They usually experience a population explosion thereby edging out native species.  Often these invaders get a free ride to their new home in the ballast water of big ships.

Learn more about invasive species including where they come from and what to do about them.

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