Killer whales disappearing why?

Local Puget orcas numbers continue to decline. Seven orcas that regularly visit Puget Sound have died since November 2008 the biggest die-off in about 10 years.
One group of scientists will use a dog to help sniff out the answers and another will chase whales in speed boats and catch the water droplets from their blow holes for analysis and yet another will tag some pod members to see where they migrate to when not in the Puget Sound area. All trying to answer the question.

Why the die-off?keiko_bow

Some speculate the continued decrease in population is due to the decrease *chinook salmon a key food. Protecting Puget Sound equals saving salmon, which equals saving orcas. The southern resident population is down to 83 animals from 97 in 1996. The orcas were listed as an endangered species in November 2005

Both Northern Resident and Southern The Puget Sound whales are most PCB-contaminated mammals in the world. PCB effects an increase when food intake decreases, because the animal uses its fat reserves for energy during food supplies are low. This releases more PCBs into circulation, increasing toxins and their effects in the body. PCBs and other toxins come from human waste, agricultural pesticides and cosmetics, fluorescent lighting fixtures, electrical appliances containing PCB capacitors, old microscope oil, and hydraulic fluids, plastics, and oil slicks.
Due to the chemical properties of PCBs they concentrate up the food chain and collect in fatty tissues.

Since all the southern resident orcas have much higher PCB levels than northern residents, this may explain the drastic southern resident decline under comparable nutritional pressures. It would also suggest that efforts should strive to simultaneously address both toxin loads and prey abundance.

* Stress – University of Washington researchers who studied the orcas hormones and toxins from scat (poop) of the remaining 83 orcas have found signs suggesting the mammals may be starving, possibly due to dwindling salmon runs. UW researchers who use a 2-liter bottle on a telescoping pole to collect whale scat for analysis have found a link between whale mortality and low levels of thyroid hormone, which partly controls metabolism. When whale deaths are up, thyroid levels are down, suggesting that the whales are starving.When whales don’t eat much, they draw down their fat reserves, where toxins are stored, said Katherine Ayres, a graduate student doing work under Wasser. When that happens, toxins enter the circulation system and could cause health problems, she said.
* Poor Nutrition – When whales don’t eat much, they reabsorb their fat reserves, where toxins are stored, said Katherine Ayres, a graduate student doing work under Wasser. When that happens, toxins enter the circulation system and could cause health problems, she said. By collecting scat and analyze the fish scales and other remains the orcas leave behind after feeding, Hanson and others run it through a genetic database.

* Ocean pollutants such as oil, plastics, cosemetics, agriculture runoff and sewage
* Vessel noise disrupts the whale’s ability to find food or disease – four citations have been issued under a new state law designed to keep vessels farther away from whales. Among the offenders were two different Canada-based whale-watching operations ticketed for coming within 300 feet of the orcas, said Sgt. Russ Mullins with the state Department of Fish and Wildlife.

* Diseases – Another group scientists from Global Research and Rescue is riding alongside the whales (How much fun is that!), using petri dishes on poles will collect air droplets from the blowholes. The breath samples are being studied to determine potential diseases..

* Decrease in Chinook salmon – A study of the births and deaths of the whales will look for a correlation between births and deaths of orca with the salmon runs. If a positive correlation is found then conservations methods can be put in place to protect the orcas and insure a adequate fish supply.

Where do they go ? – Mystery surrounds the whale’s winter migration

The Center for Whale Research on San Juan Island plans to tag the dorsal fins of six of the southern resident population of killer whales to track where they go and what they eat. For the past seven years, two of the pods have been seen in central California, possibly looking farther for food the endangered salmon.

Policing the waters -protecting the orcas

So far four citations have been issued to vessels invading the orcas waters. Under a new state law vessels farther must stay at least 300 feet away from whales.

NOAA Fisheries is also writing new rules for vessels operating in federal waters.

Resources

Die-off of Puget orcas linked to lack of key food — salmon Tucson, Arizona October.26.2008

Center for Whale Research: http://www.whaleresearch.com/

National Marine Fisheries Service: http://www.nmfs.noaa.gov/

Global Research and Rescue: http://www.grrescue.org/

University of Washington Center for Conservation Biology: http://depts.washington.edu/conserv/
http://news.yahoo.com/s/ap/20081220/ap_on_sc/endangered_orcas;_ylt=An.y4_BpPrNdSGmmhoNSnvoPLBIF
PLBIF

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2 Comments

  1. December 22, 2008 at 7:36 pm

    […] Vote Killer whales disappearing why? […]

  2. December 27, 2008 at 2:36 pm

    […] Vote Killer whales disappearing why? […]


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