Moss Landing Marine Laboratory - Herring Bay

Restoration Project

Moss Landing Marine Laboratory - Herring Bay

Restoration Objective:

The objective of this study was to determine the effects of the 'Exxon Valdez' oil spill and clean-up efforts on intertidal Fucus gardneri populations and associated organisms. They also investigated processes affecting E. gardneri recruitment, early survival and regeneration, and determined natural weathering rates for tar.

Site Selection Criteria:

Sites were selected in three categories. Control sites (unoiled and uncleaned), lightly cleaned sites and heavily cleaned sites. At each site, the study was conducted in the upper intertidal region, as this area received the most intense oiling and cleaning.

Cause Of Decline:

Oil spills can cause large scale environmental disturbances, and recovery of rocky shore communities is often not possible without cleaning oil remnants (usually tar) from the substrate. Over 38 million litres of crude oil were spilled in 1989 by the tanker 'Exxon Valdex' in Prince William Sound in Alaska. Fucus gardneri forms extensive stands covering thousands of kilometres of coastline in Prince William Sound, and provides habitat and/or food for many invertebrates. This assemblage was heavily oiled at many sites following the 'Exxon Valdez' oil spill and was subjected to a major clean-up efforts.

Key Reasons For Decline:

Water Pollution

Scientific Paper


A.P. Devogelaere, M.S. Foster
Marine Ecology Progress Series, Vol. 106.

Site Observations:

Observation Date

1st Apr 1988 – 1st Oct 1990

Action Summary:

Sites were surveyed 18 months after the Exxon oil spill. These included control sites (unoiled, uncleaned), sites that were intensely cleaned with high pressure hot water and sites that were cleaned at a lower intensity. The composition of the rocky shore algal and invertebrate community was measured over 2.5 years.

Lessons Learned:

Intense mechanical cleaning following an oil spill is detrimental to algae regeneration.

Project Outcomes:

F. gardneri cover averaged 80 % on unoiled sites but < 1 % on all oiled and cleaned sites 18 months after the spill. F. gardneri cover remained extremely low on oiled and cleaned sites 2.5 years following the oil spill. Holdfasts that survived cleaning did not resprout. F. gardneri recruitment was lowest at intensely cleaned sites, and most juveniles occurred in cracks near adults. Recruits were less abundant under adult canopies, but placing adult canopies over recruits did not decrease survivorship over 5 months. Natural weathering removed most tar with one year.

Key Reasons For Decline:

Water Pollution

Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value:

Kelp Cover