Grandpa knows, the Oceans just aren’t what they used to be: Shifting baselines, vanishing species, and oceans filled with jellyfish and plastic.

Andrew Revkin in DotEarth highlights "Emptied Oceans", a short film by Randy Olson that compares the very different experiences of two adventurers sailing from California to Hawai'i on rafts.  In 1958, Don MacFarland, sailing the Lehi, caught huge fish, encountered sharks every day, and collected thick plankton to supplement his diet during the journey.  In 2008, Marcus Eriksen, aboard Junk (a vessel made of recycled bottles and an airplane fuselage that he sailed to highlight the problem of plastic pollution in the ocean, also known as marine debris) caught few fish, saw only a two-foot long mako shark, and found more plastic pellets in the ocean than plankton.  

If you spend time on the ocean, it may appear to be wild and teeming with life, but Olson's film illustrates how "shifting baselines" can change our standards of what wild, pristine, or healthy environments are.  Baselines are very important in managing natural resources because these are used to measure the health of ecosystems and determine whether human actions are harming or helping the environment.  When baselines shift, that means we have a lower standard for environmental protection because we are measuring changes against a less-than-pristine state.  

Some call this "Old Timer's Syndrome" because older folks who saw the ocean back-in-the-day can conceptualize the magnitude of decline experienced over a generation or two.  I can relate to this concept-for most of my life I've heard stories from my grandpa, a life-long free-diver and fisherman, about his experiences plucking abalone from the rocks along the California coast, or reeling in legendary catches, day-after-day.

Jeremy Jackson, from the Scripps Institution of Oceanography, working with dozens of other scientists, found that humans have had such major impacts on the oceans for so long that baselines for ocean ecosystems shifted long ago.  In a recent article, Jackson explains that the dramatic decline in almost all ocean life is caused by the combined, cumulative impacts of these problems:

1. overexploitation (i.e. over-fishing);
2. nutrient and chemical pollution from land;
3. habitat destruction, particularly from trawling and dredging; and
4. climate change.

The situation really is dire-Jackson found that of 80 species surveyed, 91% are depleted, 31% are rare, and 7% are extinct.  Green turtles numbered approximately 90 million in the 18th century-today less than 1% of them remain.  Jackson and others predict that, if we continue without changing our behavior, we are very likely to see mass extinction of ocean life-the only thing left will be the rats and cockroaches of the sea- jelly fish and bacteria.

 What can we do?

1. Support Marine Protected Areas-these have been shown to address the problems with overfishing.  If you live in California you have a chance to show your support now!
2. Support enforcement of U.S. laws already on the books.  The standards contained in the Magnuson-Stevens Act and the U.S. National Marine Fisheries Service would result in major improvements in U.S. waters within a decade.
3. Support removal of subsidies and taxation of fertilizers-this would significantly reduce nutrient and chemical pollution with only a small decrease in food production or increased costs.
4. Reduce energy use and support renewable energy that do not contribute to the rise in greenhouse gases.