The following story about Sharks
is the second half of my research dealing with the ecological importance of
apex predators. It was also published in the Epoch Times on 5 April, 2013.
Gerry is a Malaysian based marine ecologist, Research Fellow and
Advisor to the National University of Malaysia, and marine consultant to the
Andaman Resort, Langkawi.
I was recently bemoaning the sorry state of
the Oceanic Whitetip Shark and mentioned that there was just a Conference of
the Parties (CITES) meeting in Bangkok earlier in March to look at their
protection. What was only a few years ago the most abundant large predator on
Earth is now little more than a memory.
I also made mention of the fine work of Dr. Shelley Clarke who estimated from market surveys that between
26 million and as many as 73 million sharks were harvested each year worldwide.
Her best estimate was 38 million sharks killed annually.
We may have had that wrong. On March 1, 2013 , "Global Catches, Exploitation Rates
and Rebuilding Options for Sharks," was published by Dr. Worm and three
other researchers from Dalhousie University teamed up with scientists from the
University of Windsor in Canada, as well as Stony Brook University in New York,
Florida International University (FIU) in Miami and the University of Miami. A
very powerful team indeed.
Their shocking findings are
that shark fishing is now globally unsustainable. Their more recent estimates
put the carnage at 97 million in 2010. The possible range of mortality is
between 63 and 273 million annually. This equates to somewhere between 7,200
and 31,000 sharks per hour.
"Sharks
are similar to whales, and humans, in that they mature late in life and have
few offspring” said Boris Worm. “Our analysis shows that about one in 15 sharks
gets killed by fisheries every year. With an increasing demand for their fins,
sharks are more vulnerable today than ever before."
Why am I so upset? It was never
fun swimming around in a 1000 m of water with things described by Jacques Cousteau as
"the most dangerous of all sharks". Why should I care if they are
gone?
The research I was doing
at that time looked at the make up of the marine fish community as it was
exposed to fishing pressure. Specifically, to fishing aimed at top predators on
the coral reef. I was trying to find out how much fishermen were reducing the
stocks of valuable food fish on the Great Barrier Reef .
I found that stocks were devastated by up to 95% in some places.
But I discovered
something that wasn’t known before. I came up with a mathematical expression
that predicted changes in the entire fish community. I published the work in
1982.
That’s right! Not just
the species the fishermen were catching; it looked like everything changed and
more importantly, it looked like it might never change back. Sadly, this idea
didn’t catch on and was buried in scientific libraries. Everyone believed that
if you left things alone for a while they would repair themselves and go back
to the way they were in the “good old days”. This comes from the idea of ‘renewable
resources’ and is the way we see the world around us.
The years past and things started
to go very wrong in the Caribbean . Reefs there
were being over-run by seaweed, fish were gone, and corals were dying. From
about 2000 researchers were looking at a variety of possible causes. By March,
2009 researchers
had found that fish abundance that had been stable for decades had given way to
significant declines from 1995.
By June, 2012 Dr. Roff had completed a
study raising concerns about the future of Caribbean
coral reefs. Seaweeds were blooming so fast that corals were unlikely to recover
in the absence of enough seaweed eating fish.
Now in
March, 2013; "This is a big concern because the loss of sharks can affect
the wider ecosystem," said Mike Heithaus, executive director of FIU's School of Environment
Science has been nailing
the problem down to overexploitation of the apex predators – sharks and some
groupas. It was during the last two years that this research caused my early
work to be dusted off and looked at again. My 1982 concept is now becoming a
cornerstone of contemporary thinking in coral reef management.
Put simply, we must have
all the species in reasonable numbers if we are to maintain healthy and
sustainable fisheries. Eliminating an apex predator is like pulling a couple of
‘chips’ out of your computer. It still runs but it doesn’t run the way you want
it to.
In my earlier work I
forecast that “the concept of renewable resources may not be broadly applicable
to the coral reef and the relationship between (apex) species abundance and
(change) – may be less a management tool than a picture of the demise of the
reef fish community as we know it”.
Fancy words? Not really.
Where nature is concerned we just have to understand that most of the time we
don’t understand. We can’t go into an ecological system that evolved hundreds
of millions of years before man set foot on the planet and think we can exploit
it however we wish and that it will simply cope with our being there.
If we can learn anything
from natural history it is that when systems begin to collapse there is a point
from which there may be no turning back. If you doubt this then ask the
dinosaurs for their opinion.
http://youngmarinescientist.blogspot.com/
http://geraldgoeden.blogspot.com/
http://goedensnews.blogspot.com/
http://goedenquotes.blogspot.com/
http://goedenscience.blogspot.com/
http://goedenmarineecology.blogspot.com/
http://gerryquotes.blogspot.com/
http://einsteinsnature.blogspot.com/
http://drgerrygoeden.blogspot.com/
http://underwaterinternet.blogspot.com/
http://goedenshark.blogspot.com/
