By Keith Lombardo

Imagine walking the coastline and seeing boulders covered with black shelled mollusks, stacked one on top of another, many layers thick. Now imagine this scene along the entire rocky intertidal habitat from San Francisco to Bahia Tortugas. 

Black abalone (Haliotis cracherodii) were once one of the most abundant intertidal organisms from Central California to southern Baja California. However, 20 years of intense harvesting, starting in the early 1970s, greatly reduced their numbers. Then in the mid-1980s, the species was subjected to a disease known as withering syndrome, which further decimated the remaining populations.

As a result, black abalone are now considered extremely rare and are listed as an endangered species in the United States. It is believed that populations along the Baja California coastline have been similarly impacted as well. Unlike in the United States, extensive re-surveys have not been conducted in Baja and the current status of the species south of the border is relatively unknown. With this in mind, Science Team 6 (www.scienceteamsix.com) headed south to Punta Mazo Nature Reserve in San Quintin Bay to explore the intertidal habitat along this magnificent piece of coastline.

During a previous trip to San Quintin, we had noticed an extensive series of volcanic benches and boulders that were exposed during low tide events. Upon our return to San Diego, we found that at least two locations near the reserve were surveyed for black abalone in 2004. Unfortunately, those surveys revealed that black abalone were virtually non-existent. However, recent monitoring efforts in southern California have suggested some positive growth trends in black abalone populations. These upward trends, coupled with the sparsity of data in Baja, warranted taking a closer look along Punta Mazo coastline.

Once conspicuous, black abalone are now scarcely seen out in the open. One must crawl up, over and under boulders and peer into deep crevices to find them. Our team spent several hours each day scouring the intertidal for any sign of this now secretive species. It didn’t take long to determine that the rocky intertidal along the Punta Mazo Reserve is excellent black abalone habitat. Everything this species would need is present. The only thing missing is the species itself! 

But crawling through the intertidal and looking in every crevice and corner allows one to observe all the many other species that make up this unique habitat. What started as a black abalone survey quickly doubled as an opportunity to document the tremendous intertidal assets protected by the nature reserve. In just two 3-hour efforts, we documented nearly 70 intertidal species, including Spanish shawl (Flabellina iodinea), keyhole limpet (Megathura crenulata) and the solitary anemone (Anthopleura sola). Our team was in agreement that the Punta Mazo intertidal rivaled the best preserved intertidal habitats in southern California and yet somehow it seemed a bit more unique. It was like a window into the past had opened. 

In many ways, Baja represents southern California of long ago when the coastlines were undeveloped and wild. As we stepped out onto the rocky intertidal benches of Punta Mazo, we might as well have been in San Diego of the 1700s. While anthropogenic impacts can be found, the Punta Mazo tidepools likely haven’t changed much over the past millennia. 

Punta Mazo, and places like it in Baja California, is not only representative of our southern California past but they are simultaneously our future as well. One of the most agreed upon effects of climate change is a profound shift in species and habitats. As the planet warms, terrestrial and marine species will move poleward seeking new habitats that resemble the more favorable niches provided by their historic environments. For Baja species, the northward march will bring them to southern California where our management actions always seem to be reactive and our plans centered on the rehabilitation of long-degraded spaces. And this is often done with little knowledge of historical baselines or reference conditions. But before us is an excellent opportunity to document and understand a relatively undisturbed series of ecosystems and apply this knowledge to future management actions.

While this initial survey effort didn’t reveal any definitive signs of black abalone, the abundance of high quality habitat suggests that we will eventually find this elusive species. But perhaps more importantly, these investigations serve as a means of documenting the biodiversity and the ecologies found within the protected areas of Baja California. Quantifying baseline species diversity is critical for any organization that aims to better understand how to protect and preserve their natural resources. Through the lens of climate change, baseline surveys and studies can also provide invaluable information to forward thinking managers who aim to proactively manage our rapidly shifting landscapes and protect the ecologies that sustain our natural systems and, ultimately, ourselves. 

About the author

Keith currently serves as a Coastal Ecologist and Chief of Natural Resources & Science at Cabrillo National Monument, a unit of the National Park Service, in San Diego. His academic training focused on plant and fire ecology of the southwestern United States while his professional career has been dedicated to the coastal terrestrial and marine systems in southern California and Baja. Keith serves as an Associated Researcher for Terra Peninsular and as a Scientific Advisor for Science Team Six.