Monterey Bay National Marine Sanctuary






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Rocky Shores:
Shipwrecks, Restoration, Monitoring, and Resource Management

In April 20, 1996 the fishing vessel Trinity ran aground just north of Point Pinos on the Monterey Peninsula. A salvage operation and studies on both recovery rates and restoration techniques for the damaged rocky shore followed this event. In 1999 it is appropriate to summarize results from these studies as human impacts to rocky shores have come to the forefront of Sanctuary management and significant progress has been made for monitoring this habitat.

The 51-foot, steel hull Trinity ran aground on the Monterey Peninsula in 1996. Scientists have been studying recovery rates for the rocky shore damage caused by this shipwreck. (Andrew DeVogelaere © MBNMS)

When the 51-foot, steel hull seiner ran aground, it crushed granite rock and scraped off algae and invertebrates. As the ship was flipped further up the shore during removal via large tow truck winches, tractor tires effectively cushioned against further rock crushing. However, this was a two-day process and, where the ship and tires were left in the surf overnight, wave agitation created rubble beds beneath them. The habitats impacted were lower intertidal surf grass beds, mid-intertidal mussel beds, and higher intertidal red algae assemblages.

Public Concerns Spur Action in Pacific Grove

In early May 1999 citizens brought to the Pacific Grove City Council their concerns about the perceived declining health of the local tidepool areas. They attributed the decline to the impact of human activities and urged the Council to push for more aggressive conservation measures.

It was clear, however, that controversy existed over the status of the tidepools. The City Council decided to establish a Task Force of individuals with interest and expertise in marine conservation to address the issue. Prospective members were invited from marine research institutions, local government entities, environmental organizations, and citizens. The Task Force hoped to bring together concerned citizens and researchers to accomplish the common goal of increased protection.

The City Council specifically directed the Task Force to focus efforts on educational opportunities and to identify research that could clarify the threats to this special natural resource. The tidepool areas along the shoreline of Pacific Grove are already protected—by the Monterey Bay National Marine Sanctuary and the Pacific Grove Marine Gardens Fish Refuge and through a city ordinance. Despite these protective measures, however, some confusion exists over the jurisdictional authority and specific limitations in the area. Initial efforts of the Task Force sought to clarify these.

The Task Force's next charge is to develop educational signs for the shoreline area to increase awareness of both the value of these resources and their protected status. It is also working with BAY NET, a local volunteer network affiliated with the Sanctuary, to see if tidepool interpretation can become part of that group's program. Lastly, a Task Force subcommittee is developing a research program to gather comparative data on local tidepool areas and to identify possible explanations for degradation that might exist.

Sanctuary staff have been intricately involved with the Task Force, contributing to many of the successes accomplished so far. Awareness about marine resources is high throughout the entire Sanctuary region and the efforts in Pacific Grove are simply another step in the ongoing process of local citizens leading the way to protect the marine environment that they value so much.

--Michelle Knight
Chair, Pacific Grove Tidepool Task Force

Recovery within the damaged areas has been slow. After two years only a few mussels and sea grasses have colonized disturbed areas in those habitats and diversity remains low, even though the dominant red algae are now common in the red algal assemblage. Other studies in central California have found that disturbed mussel beds can take more than ten years to recover. Therefore, while rocky shore systems experience natural disturbances from rolling rocks and large waves, physical disturbances can have long-term impacts to the organisms living and feeding there, as can humans, as we visit these sites for social and professional purposes.

Restoration of rocky shores is often discussed after oil spills and ship groundings,or as mitigation for construction projects. A few restoration efforts have been experimented with, but the methods were expensive and had limited success. In particular, moving individual plants is a lot of work and most die because they have adapted to a specific microhabitat and orientation. We transplanted intact red algal assemblages on boulders into the rubble beds created during the salvage operation. In this case (moving assemblages rather than individual plants), more than 80 percent of the transplants remained after two years; now we would like to learn if this method enhances recruitment by providing a local source of spores.

Ship groundings are obvious events; however, as human coastal populations increase, visitation (which is less obvious) is a growing concern. As expressed at a past Sanctuary Currents Symposium and in the scientific literature, lower biodiversity and smaller size of rocky shore organisms have been correlated with increased human access in southern California. In the Sanctuary this year, the question is being addressed by management agencies through a draft Master Plan for the Fitzgerald Marine Reserve, creation of a tidepool advisory committee by the city of Pacific Grove, and a list of recommendations by the Sanctuary Advisory Council's working groups. It is clear that there is a need to monitor rocky shore systems in order to distinguish between human impacts and natural variability, and then to assess the effectiveness of management practices in cases where they need to be implemented.

In collaboration with Moss Landing Marine Laboratories, the Sanctuary completed a review of forty-eight current and historic rocky shore monitoring programs within the Sanctuary boundaries. While this habitat and region of the world are among the most studied and the rocky shores maintain relatively high biodiversity, there remain extensive information gaps on the Big Sur coast and boulder habitats (it is much easier to work on flat rock benches). Moreover, comprehensive long-term monitoring is missing. A significant component of this work was begun this year as the UCSC-led Partnership for Interdisciplinary Studies of Coastal Oceans set up fourteen rocky shore monitoring stations, and it will be working closely with the Sanctuary on resource management issues.

--Andrew DeVogelaere
Monterey Bay National Marine Sanctuary

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Last modified on: March 31, 2000