Last year I mentioned that another exotic sea weed was discovered off the shores of Santa Catalina Island. Dr. Kathy Ann Miller of the University of California Herbarium notified me about its discovery in the waters off the Wrigley Marine Science Center. Initially it was believed to be Sargassum horneri, a native of Asia. A later collection by Dr. Jack Engel of the Tatman Foundation included mature, reproductive portions of the alga allowing a positive identification as Sargassum filicinum, also an Asian exotic seaweed. Within months it came to dominate much of Catalina's leeward coast, aided in part by extremely warm water temperatures last summer which caused our native giant kelp to die off.
Regular readers may remember that other exotic sea "weeds" including Caulerpa taxifolia, Sargassum muticum and Undaria pinnatifida have been found in our waters. One definition of "weed" that I read in an article by novelist John Fowles in Sports Illustrated back in the 1970's was "a plant out of place." Now that definition could apply to a native plant found in your garden of beautiful but non-native flowers; or one of your non-native garden flowers that "escaped" (as a seed, not by crawling out on its roots) and now grows in the midst of a native plant assemblage here in the hills of Catalina.
We ecologists are concerned about the impact of non-native plants and animals on the ecology of the native species in a region. They may out compete the natives like the bright yellow Dyer's greenwold (or Canary Island broom) introduced in the early 1930's to landscape the Hotel St. Catherine. Just take a look at the roadside as you drive up to the Hog's Back Gate, or into upper Descanso Canyon, and you can easily see why this is a concern when its yellow flowers are blooming. About one third of the plants known from Catalina are non-natives from Mediterranean Europe, South America and even Africa! In fact many of the island's hillsides resemble southern European landscapes due to the dominance of species from that region which have outcompeted our natives.
Many of our non-native land plants came in the ships used by early explorers, traders and colonists who visited and settled southern California. With respect to the ocean, the invasions there are also a hidden "cost" of international trade. The container ships that increasingly visit the ports of Los Angeles and Long Beach bring sea weed spores in their bilge water, or algae attached to their hulls, that can "escape" and colonize our waters. In fact, the new Sargassum filicinum was first detected in Long Beach Harbor in 2003. Perhaps a private vessel, or even a cross-channel passenger boat, may have brought this intruder to Catalina waters. Now, I like the Sony video cameras I use to document our undersea world not to mention my Toyota car, and by buying these imported products I am an accomplice in these ecological intrusions.
Back in the 1950's the community next to ours became home of the second McDonalds restaurant in the world. I remember when the signs said "several hundred thousand hamburgers sold." It was a treat to go there with my family for a meal that cost a mere $0.47. Herb Peterson, one of our neighbors in Chicago, even invented the Egg McMuffin! I still enjoy the occasional meal at McDonalds when I'm on the mainland. However, now even when I travel thousands of miles from home, I am confronted with McDonalds restaurants in most foreign countries. I greatly prefer sampling the local fare, and stick to the small restaurants run by native families that serve traditional food. I will admit to trying a curry burger at a McDonald's in Hong Kong though! The proliferation of McDonalds, Walmarts and the like throughout the world is an example of the homogenization of our culture. Thank goodness here on the island we have the likes of Antonio's, Armstrongs and Steve's Steakhouse instead of McDonalds, Burger King and Wendy's; and Chet's Hardware instead of Home Depot or Lowe's.
When I travel to different countries, I go to experience the uniqueness of those countries... to eat their food, sleep in their hostels and guest houses, and talk with their residents in their language as much as I can (and "beer" is one of the first words I learn after "please" and "thank you"). Likewise when I travel to distant exotic dive sites, I want to see the coral reefs or other ecosystems that are native to their region. The last thing I would want to see there would be giant kelp, unless I were diving southern Australia, South Africa or Chile. I don't want to see the ecosystems of Catalina, or the rest of the world, homogenized the way the cultures of the world have been in this increasingly global economy.
This potential for homogenization of the ecosystems on land and in the sea threatens what is really unique about our island and waters. Of course our waters are too cold for coral reefs to establish, at least not until global warming affects us to a greater extent. However, marine species from oceans with similar characteristics including those from parts of northern Asia, South America, southern Australia and South Africa may gain a foothold here as trans-oceanic shipping increases. Likewise, our own species may be transported and become exotic "weeds" in other temperate regions of the world.
Some of you may have been aware of the vehicle inspection program I initiated while Vice President of the Catalina Conservancy. Any incoming construction or other heavy vehicle potentially used off-road on the mainland required an inspection to ensure it did not bring seeds of non-native plants to the island. Although some felt it was a draconian measure, most of the drivers understood once it was explained to them. Perhaps we need to consider a similar program to inspect the ships entering our mainland harbors from regions which might have species pre-adapted to our waters.
This summer ocean temperatures were not as warm as last year. Our giant kelp forests are alive and fairly healthy. I hoped they might shade out the tiny Sargassum spores waiting on the ocean floor for sunlight to reach them. However, I have begun to see smaller, immature Sargassum filicinum plants dominating rocky reefs in some of our dive sites as they begin their annual growth cycle. I even saw a mature plant at Long Point on a recent dive. I don't want Catalina to be dominated by Asian exotic sea "weeds," just lovely Asian divers who need to buddy up with the good Dr. Bill!
© 2007 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass" or "Common Fish and Invertebrates of the Sea of Cortez" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!
Container ship involved in trans-Pacific shipping and private sailboat crossing the Channel to Catalina;
McDonalds arches as a symbol of cultural homogenization and the invasive Sargassum filicinum.
This document maintained by
Dr. Bill Bushing.
Material and images © 2007 Star Thrower Educational Multimedia