Saturday, August 15, 2009

Giant Kelp: preserving a cornerstone of California's marine ecosystem

A dive buddy who I have not seen in many years was vacationing with his family on the west coast and we hooked up this past Thursday to do a day of diving at Anacapa Island, the southernmost island in the northern Channel Islands group. He had not been diving the Channel Islands since he moved back east some 14 years ago, so it was going to be interesting to see and hear his reaction to being back in the ol' stomping grounds where we had logged many a dive.

Conditions were typical for this time of year: a little overcast and the water was it's usual summer green tinge with about 20 feet of visibility. Not bad since we were going to be spending most of our time cruising through the kelp.

Giant kelp forms one of the foundations of California marine ecosystems, providing food and shelter for a variety of animals from its root-like holdfast structure right up to the canopy that is formed when the stalks reach the surface and continue to grow. At its healthiest, a field of giant kelp is like a dark mountain forest; gliding between the stalks is like flying past aged timbers.

California's kelp forests have suffered over the years and the fields are not quite as robust as they were, say, 20 years ago. With kelp being very sensitive to warmer temperatures (actually dying off when the water exceeds 70 degrees for any sustained period of time), the forests have felt the impact of seasonal El Nino warm water currents, warmer summers and milder winters, and pollution. Also, in some areas, with the reduction of certain gamefish that feed on urchins (which in turn feed on kelp), the increase in the population of these spiny echinoderms has wiped out entire kelp beds. There are several organizations and ongoing projects involved in replanting kelp and, since kelp can grow amazingly fast given the right conditions, these replanting efforts hold great promise in bringing back kelp forests to their former glory as an oasis that attracts sealife of all kinds. But it all hinges on those "right conditions" of clean water and cooler temperatures.

There may not be much that we can do about seasonal temperature changes like El Nino currents (although some scientists believe that the duration or severity of these weather patterns are effected by the overall climate change issue), but we can certainly do something about the impacts of pollution, CO2 emissions, and over-fishing that contribute to less than ideal conditions for the kelp forests.

My dive buddy and his daughter had a great time diving; he fell right back into his old ways of peeking under every rock outcropping or crevice with his light, to see what might be making a home there. We had one large and curious male sheephead follow us around, and on another dive we were playfully bombarded by sea lions from a local rookery. But he did notice a lack of fish and other sea critters he remembered from past dives. And I couldn't argue with him: things have changed.

Let's hope that we - the consumers, the businessmen, and the decision-makers - take ocean conservation seriously and act swiftly and responsively. Otherwise, we will be left with only memories and maybe what we find on display in aquariums and museums.

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