Earth From Space

The Nova program ( http://www.pbs.org/wgbh/nova/space/earth-from-space.html) earth from space is a two hour video that explains many of the environmental connections. It is a bet too long and so this blog assignment will count double i.e. it is a two week assignment instead of only one.

Copy the link into your browser:   http://www.pbs.org/wgbh/nova/space/earth-from-space.html

Environmental "ramblings" :-)

Your assignment for this week is to listen to the Audio that has been added to your Course Document on BB and to add your comments here. Thanks.

Overfishing = Extinction ?

The following is a brief excerpt about the possible effects of overfishing. The numbers should be very enlightening as to what is happening in this area:
     ***************************************************************************

To explain why overfishing is a problem we first have to get an idea on the scale of the problem. This is best done by looking at some figures published by the UN Food and Agriculture Organization. 1 The FAO scientists publish a two yearly report (SOFIA) on the state of the world's fisheries and aquaculture. 2 The report is generally rather conservative regarding the acknowledging of problems but does show the key issue and trends. Due to the difficulty of aggregating and combining the data it can be stated that the SOFIA report is a number of years behind of the real situation.

• 52% of fish stocks are fully exploited
• 20% are moderately exploited
• 17% are overexploited
• 7% are depleted
• 1% is recovering from depletion

The above shows that over 25% of all the world's fish stocks are either overexploited or depleted. Another 52% is fully exploited, these are in imminent danger of overexploitation (maximum sustainable production level) and collapse. Thus a total of almost 80% of the world's fisheries are fully- to over-exploited, depleted, or in a state of collapse. Worldwide about 90% of the stocks of large predatory fish stocks are already gone. In the real world all this comes down to two serious problems.

• We are losing species as well as entire ecosystems. As a result the overall ecological unity of our oceans are under stress and at risk of collapse.
• We are in risk of losing a valuable food source many depend upon for social, economical or dietary reasons.

The single best example of the ecological and economical dangers of overfishing is found in Newfoundland, Canada. In 1992 the once thriving cod fishing industry came to a sudden and full stop when at the start of the fishing season no cod appeared. Overfishing allowed by decades of fisheries mismanagement was the main cause for this disaster that resulted in almost 40.000 people losing their livelihood and an ecosystem in complete state of decay. Now, fifteen years after the collapse, many fishermen are still waiting for the cod to return and communities still haven't recovered from the sudden removal of the regions single most important economical driver. The only people thriving in this region are the ones fishing for crab, a species once considered a nuisance by the Newfoundland fishermen.

Fishing down the food web

It's not only the fish that is affected by fishing. As we are fishing down the food web 3 the increasing effort needed to catch something of commercial value marine mammals, sharks, sea birds, and non commercially viable fish species in the web of marine biodiversity are overexploited, killed as bycatch and discarded (up to 80% of the catch for certain fisheries), and threatened by the industrialized fisheries. 4 Scientists agree that at current exploitation rates many important fish stocks will be removed from the system within 25 years.