Subject: pollution and whales

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     Hi Whitney.  That sounds like a really great research paper that 
     you're working on.  Let me see if I can give you a little information 
     to help you out.  
     
     First, there are many types of pollution.  There is noise pollution 
     (like sounds from ships), plastic (which whales can get tangled in or 
     eat), oil spills (we don't really know the impacts on whales.  Most of 
     that information comes from seals, sealions, and sea otters which have 
     lots of hair that gets matted with oil and then the animals get sick 
     from eating the oil), or toxins (like PCBs, organochlorines, heavy 
     metals, etc.).  Another consideration is the impact of air pollution.  
     I would suspect that your question was probably about toxins.
     
     The whales and dolphins are at the top of the food chain, which means 
     that they may be affected by bioaccumulation of toxins thru the food 
     chain.  There is insufficient information to determine how, or at what 
     levels and in what combinations, environmental contaminants may affect 
     whales and dolphins.  There is growing evidence for other animals of 
     several physiological abnormalities, including skeletal deformations, 
     developmental effects, reproductive and immunological disorders, and 
     hormonal alterations.  It is also possible that the chemicals cause 
     immunosuppression, rendering a dolphin or whale susceptible to 
     diseases.  Studies of seals in the North Sea area suggest a link 
     between pollutants and a depressed immune system.  Some dolphins that 
     have died during mass strandings, and been infected with morbillivirus 
     also were found to have high levels of contaminants in their boedies.  
     It is very difficult to draw a link between a contaminant and its 
     effect on a whale for many reasons.  First, much of the information 
     comes from stranded or dead animals (obviously these are not healthy 
     animals and may not be representative of an actual impact of a 
     chemical).  Second, we don't really know how much of a chemical is 
     really bad for a whale/dolphin.
     
     The interesting thing is, that dolphins and whales can be used as 
     indicators of the health of the ecosystem, because remember, just like 
     us, they are at the top of the food chain.  We can probably assume 
     that what the whales are being exposed to is what we're being exposed 
     to.
     
     Hope this answers your question.  I realize that this is not very 
     optimistic sounding.
     
     Dagmar


______________________________ Reply Separator _________________________________
Subject: No Subject
Author:  PHIL1476@aol.com at ~smtp
Date:    2/4/98 10:03 AM


Hi! I'm Whitney and I'm writing a research paper on the environmental effects 
on whales. I was wondering if you have any information on how pollution has 
affected whales today? Thanks so much!
     
P.S. I home school and I'm in the sixth grade!

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