MONTEREY, California (13 June 2007) -- More endangered Hawaiian monk seals are trapped and killed by marine debris during years when the El Nino phenomenon warms tropical Pacific waters, according to University of Hawaii researchers. El Nino events cause ocean currents carrying marine debris to flow farther into the Northwestern Hawaiian Islands where most monk seals live. The seals often drown or starve if they can't free themselves from fishing nets and other floating garbage. Scientists knew marine debris was a top killer of the seals, but they lacked an explanation for the disparity between years. Since 1982, the number of seals known to be entangled have ranged from a low of two in 1985 to a high of 25 in 1999. Mary Donohue, study co-author, was helping analyze monk seal entanglement data for the federal government's protected species program when she noticed a pattern. "I had plotted it out, and when I looked at the peaks, to me it looked like a graph of El Nino," said Donohue, a marine mammal ecologist with the University of Hawaii's Sea Grant College Program. El Nino events usually occur every 3 to 7 years and can be predicted by meteorologists. Donohue and co-author David Foley of the Joint Institute for Marine and Atmospheric Research published their findings in the March issue of New Scientist and the April edition of Marine Mammal Science. Donohue said she hoped the research would help experts determine when they should spend more time looking for entangled monk seals to rescue. The findings may also help debris removal expeditions do a better job extracting marine debris from the ocean before it reaches the islands where the seals give birth. | | Many endangered monk seals die after becoming entangled in fishing nets. Only about 1,200 animals remain as the population declines about 4 percent a year. Last month, an adult monk seal drowned after it became trapped in an unattended fishing net off Oahu's Makua Beach. The state last week charged a Waianae man with violating state gill net rules by using a net longer than 125 feet and failing to check on his net in the water. Only 1,200 seals remain in the wild, with most living in the Northwestern Hawaiian Islands. Fewer than 100 live in the main Hawaiian Islands. National Oceanic and Atmospheric Administration scientists say the seal population has recently been dropping by 4 percent a year. Many seals are also being killed by sharks while others are dying of starvation because they can't find enough food. SOURCE - Sci-TechSCUBA FORUMDISCUSS THIS TOPIC - Dive in and have your say at Scuba ForumCDNN Related NewsHAWAII - Too late to save Hawaiian monk seal? |
