Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO): subtidal component
- Pete Raimondi
University of California, Santa Cruz
- Mark Carr
University of California, Santa Cruz
- David and Lucille Packard Foundation
- Gordon and Betty Moore Foundation
- Monterey Bay National Marine Sanctuary
The Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) subtidal monitoring program was started as part of the initial PISCO grant from the David and Lucile Packard Foundation in 1999. The goal of PISCO is to investigate the nearshore rocky reef marine ecosystems of the west coast of the U.S. in an innovative, coordinated, and interdisciplinary fashion in order to advance scientific frontiers and to provide better understanding for conservation and management decisions.
The PISCO subtidal research program is a cooperative effort among three of the four PISCO universities: Oregon State University, UC Santa Cruz, and UC Santa Barbara. Similar to PISCO's intertidal and oceanographic research, patterns detected through our large-scale, long-term subtidal monitoring program motivate and direct additional studies on the ecological processes responsible for the structure and dynamics of kelp forest communities.
Monitoring surveys are conducted annually at all sites during the late-summer months of July through September. Subtidal community surveys began in 1999 by sampling a total of 6 sites in central California. Over the past five years PISCO has continuously added sites to increase the spatial resolution and scale of the monitoring program. PISCO-UCSC monitors 15 (including Cambria and Andrew Molera) sites within the Sanctuary (Figure 1). This number is likely to continue to grow to eventually approximate the scale of monitoring that PISCO conducts in intertidal habitats. Central to the success and value of the expansive scale of this monitoring program is the development of survey designs and sampling protocols that are standardized across all three institutions and monitoring sites.
The Central California sites, overseen by UC Santa Cruz, are the only sites listed for the purposes of the MBNMS SIMoN database.
Summary to DatePISCO's subtidal monitoring program provides information critical to our understanding of kelp forest ecosystems as well as informing approaches for their management and conservation. Monitoring studies describe patterns of natural variation in species abundance, community structure and ecosystem function and the biological and physical processes that underlie such variation. Knowledge of this natural variability is fundamental for identifying changes induced by human activities in the coastal environment. This program is the first large-scale, long-term kelp forest monitoring program of its kind.
PISCO has established long-term monitoring sites in three regions along the west coast (Oregon, Central California, and Southern California) near the collaborating universities. These regions are representative of the west coast's three major faunal provinces. Within each region, sites are distributed among oceanographic regions and conditions (e.g., varying degrees of coastal upwelling) as well as different geologic attributes (e.g., types of rocky bottom). In addition, sites are paired inside and outside of existing marine reserves within each region. This allocation of monitoring sites allows us to contrast the structure and dynamics of kelp forest ecosystems in differing oceanographic and fishing regimes.
Our monitoring approach is based largely on diver surveys that quantify the density and abundance of the macroalgae, invertebrates and fishes that constitute these communities (Figure 2). This approach allows us to quantify both the patterns of abundance of targeted species as well as characterize changes in the communities they reside in. Such information provides managers with insight into the causes and consequences of changes in species abundance. Such changes in species and their habitats result from human or non-human factors and as such form the basis of "ecosystem-based management" of kelp forest communities.
This project is on-going. We continue to collect data annually at all of our sites. In addition, we continue to increase the number of sites we sample each year (e.g., Andrew Molera in 2003). In summer 2003 we sampled 10 additional sites between Point Sur and Cambria. Overall, PISCO-Santa Cruz surveyed kelp forests at 25 sites along the coast of California (23 in the Sanctuary).
We expect to compile a 5-year data summary in the near future.
- Fish assemblage structure (relative abundance of species) differs regionally and inside versus outside marine reserves along the central coast of California (Figure 4).
- Significantly greater numbers of fish were seen for 5 out of 13 common species targeted by fishing (mostly rockfish in the genus Sebastes), whereas only 1 out of 10 common species not targeted by fishing was more abundant within reserves.
- No significant differences in either the average length or the proportion of larger fish were seen between reserve and non-reserve sites.
- Based on estimates of size, density and Length-Specific Fecundity for individual species, targeted fish populations have significantly higher biomass and larval-production capacity within reserve boundaries.
DiscussionData from the first six years of PISCO monitoring indicate reserves in the Monterey Bay National Marine Sanctuary area are enhancing populations of at least some important fishes. Continued monitoring in coming years will improve our understanding of reserve effects on population size-structure and associated benefits to reproductive success and population sustainability.
The findings presented below are unpublished, preliminary results, and should not be cited, copied, or referenced without the permission of the principal investigators.
Large-scale spatial patterns of the canopy assemblages of Macrocystis and Nereocystis from 1999 to 2002 were dominated by Macrocystis. Trends in kelp abundance were locally variable; kelp declined over time at some sites and remained stable at others (Figure 3).
Large-scale spatial patterns of the sub-canopy assemblages (including Pterygophora, Laminaria, and Cystoseira) from 1999 to 2002 showed strong local variation in density and species compostion.
Purple urchins (Strongylocentrotus purpuratus) showed strong regional-scale patterns of abundance that were correlated to the distribution of their primary predator, the southern sea otter.
Reef fish assemblages are correlated with habitat type. For example, greenlings and some perches (e.g., rainbow perch) dominated the fish assemblages associated with low-relief habitats; whereas other perches (e.g., striped and black perch) and rockfishes (e.g., gopher, kelp, black and yellow rockfish) dominated assemblages on high-relief reefs.
- Dispersal & Recruitment
- Habitat association
- Non-indigenous species
- Age structure
- Size structure
- Stock assessment
- Substrate characterization
Study MethodsDiver visual surveys
Uniform point contacts
Figures and Images
Figure 1. PISCO long-term rocky reef monitoring sites.
Figure 2. PISCO visual diver survey methods.
Figure 3. Kelp canopy assemblage patterns.
Figure 4. Multivariate analyses show that fish assemblages differ across the three study regions and inside vs. outside reserves. Species which show significant differences in and out of reserves are mostly those targeted by fishing, such as rockfish, lingcod and sheephead, while other, non-targeted species, such as surfperch, contribute to differences across the three study regions.