Energy and the Environment-A Coastal Perspective

The electromagnetic fields produced by the cables have the potential to affect sea turtle migration. Leatherbacks have magnetic sensitivity and use cues from the earth’s magnetic field to steer in given directions (Sale 3742). As hatchlings, sea turtles possess an innate magnetic compass that enables them to travel far distances (Sale 3742). They ride along the ocean currents, exerting very little energy themselves which inhibits their ability to sense location using the visual, depth, salinity, and temperature cues that many other marine animals use (Sale 3740). It was has been hypothesized that leatherbacks rely on magnetic fields in order to return tens of years after their birth to the same general area to breed (Sale 3740). A recent study done on green turtles in supported this hypothesis. Green turtles were transferred by boat and released into the ocean. Those released without head-attachments successfully returned to their nesting beach while those that had head-attached magnets altering the local magnetic field took significantly longer paths to return home (Sale 3741). This study suggests that if cables extending from any type of ocean energy generator produce a significant magnetic field, sea turtles would have trouble navigating back to their nesting sites, therefore potentially lowering reproduction numbers.

Information could not be found on the direct effect of cables on sea turtles. Further testing needs to be done to determine whether a strong enough magnetic field would be produced by the cables to significantly disorient sea turtles.

Sea Turtle Life Cycle:

http://www.colorado.edu/intphys/Class/IPHY3730/image/lifecycle.gif

Migrating Routes:

http://www.mar-eco.no/learning-zone/__data/page/91/migration-route.jpg

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