Quotes and [minimal comment]On the CBC radio program Quirks and Quarks last Saturday there was a fellow explaining his take on the catastrophic decline of sea otters in the Aleutians and its cascading ecological effects.
It went something like this;
After WW II, the Russians and Japanese turned their marine prowess to hunting whales – these whale hunters were apparently not interested in Killer Whales (Orcas). The decimation of Pacific whale stocks left Killer Whales lacking sufficient numbers of their formerly abundant prey. Orcas turned to killing sea otters that are so small bodied that they would not previously have served as anything but snacks.
The diminished control of sea urchins by sea otters allowed an explosion of urchins which destroyed much of the giant kelp forests that provide habitat for all kinds of juvenile marine species that are essential elements of the food web, with the result that many fish species began to decline.
All of this apparently started with the unsustainable harvest of really big protein packages (whales).
Peter Salonius, 11 November 2008
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I think it works both ways..... Any thing/species out of balance affects the whole chain of being the whole predator/prey relationship. Species can go out of balance without the human influence - weather , other natural events can do this, but they usually return into balance - minus interference from humans. However Human Species is influencing/interfering , because of his huge numbers, with every function of earth and with such a huge footprint, every thing/species is out of balance, endangered, threatened etc. etc. - or at the other extreme exotic, introduced (by humans) species are eliminating native species - and human interference prevents any possibility of regaining a balance
"Cat Got Your Fish?" - Thoughts about a green diet cat
Per capita meat consumption more than doubled over the past half-century as the global economy expanded. It is expected to double again by 2050. Which raises the question, what does all that meat eat before it becomes meat?
Increasingly the answer is very small fish harvested from the ocean and ground into meal and pressed into oil. According to a new report by scientists from the University of British Columbia and financed by the Pew Institute for Ocean Science, 37 percent by weight of all the fish taken from the ocean is forage fish: small fish like sardines and menhaden. Nearly half of that is fed to farmed fish; most of the rest is fed to pigs and poultry.
The problem is that forage fish are the feedstock of marine mammals and birds and larger species of fish. In other words, farmed fish, pigs and poultry - and the humans who eat them - are competing for food directly with aquatic species that depend on those forage fish for their existence. It's as if humans were swimming in schools in the ocean out-eating every other species.
The case is worse than that. When it comes to farmed fish, there is a net protein loss: it takes three pounds of fish feed to produce one pound of farmed salmon. This protein pyramid - small fish fed to farmed fish, pigs and poultry that are then fed to humans - is unsustainable. It threatens the foundation of oceanic life.
The report's authors suggest that it would be better if humans ate these small fish, as many cultures once did, instead of using them as feed. That is one way of addressing the problem of net protein loss. The real answers are support for sustainable agriculture in the developing world and encouraging healthy, less meat-based eating habits as a true sign of affluence everywhere.
Source: The New York Times, editorial, reproduced for non-commercial use only.