Small kelp harvester*
When I was a pup growing up in Southern California, I recall occasionally seeing large, dark, Japanese factory ships close off the shore raking in vast gobs of California’s signature kelp forests. At 5 years old, I didn’t have a systematic understanding of what was happening, but I sensed that it was bad. T
hese ships were a product of an ill-advised kelp-harvesting program promoted to Japan by the U.S. to help them rebuild their WWII-devastated economy. The kelp was being used as a food supplement and as fertilizer. (Another of these “economy-building” programs was the promotion of Japanese commercial whaling…)
At the time the kelp was considered a nuisance; getting tangled in the propellers of the fishing boats trying to reach the fish “hiding” in the kelp forests. Clear-cutting the kelp would provide access to the fish! (…or so the theory went).
I don’t recall how or when someone realized it was a lousy idea and pulled the plug on the industry, but by the time they did, a whole lot of damage had been done. Nobody had taken any comprehensive baselines of habitats and species, but the sea otters that were once present all along the Pacific Coast from San Diego to the Gulf of Alaska, had retreated far up the coast to Monterrey Bay and above.
Of course the otters were responding to the poor state of their favorite food – the abalone – which feeds on the kelp. And the damage to the ecosystem throughout all coastal taxa sent California coastal ecosystems into wild oscillations – arguably echoed in the recent kelp die-off that has been ravaging our kelp forests since 2014.
Initially set in motion by a marine “heat wave” and then exacerbated by cascading impacts of urchin population blooms, starfish wasting disease, and the scrambling up of the entire trophic pyramid. What this has devolved into is the decimation of the kelp forests. Over 90% of California’s North Coast kelp has disappeared – transformed into “urchin barrens” where the kelp can’t take hold before being eaten by the urchins.
So it is with some delight that – defying all predictions, kelp forests in some areas of California’s northern coast are bouncing back! Nobody is quite sure why, but it is encouraging.
Will it last? Hard to tell – because now that we understand that habitats are ecosystems, the variables that set these cascades in motion are complex, and as indicated in this case, difficult to predict.