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L.A. Dolphin Project 2


dolphin and seabird







Looking at the existing scientific literature it's rare to find any detailed description of dolphin, sea lion and seabird aggregations at sea due to the complexity of following and recording the behavior of these fast-moving and widespread animals from the surface. The Santa Monica Bay, in California is an excellent site for the study of local aggregations between these marine species due to its relative shelter from open ocean conditions and the presence of three submarine canyons that provide nutrient rich feeding areas.

California sea lions in the Santa Monica Bay
California sea lions “porpoising” offshore in the Santa Monica Bay

Overlapping prey and habitat provides opportunities to study species aggregations

The overlapping of prey and habitat for sea lions, seabirds and three dolphin species (bottlenose dolphins, short-beaked common dolphins and long-beaked common dolphins) in Santa Monica Bay, California, offers an opportunity to learn more about these animals and whether either, any or all derive some benefit from aggregation with other species.

An OCS research study conducted between 1997-2001 investigated whether these aggregations were food-based, and found that sea lions actually take advantage of the superior ability of dolphins to echolocate food in common foraging grounds (see publications).

How is research data collected in this study?

Utilizing a variety of data accumulation methods including photo-identification of individuals, seabird recognition, cetacean focal group behavioral descriptions, bioacoustic recording, fish scale collection for prey identification, and correlated surface and underwater video filming, we currently aim to shed more light onto the meaning and dynamics of marine mammal and seabird aggregations.

dolphin feeding off Pt.Dume LADP researchers identifying seabirds
Feeding off Pt. Dume, California   LADP researchers
identifying seabird species

Project Objectives

The current phase of this project is to expand upon our previous study to:

  • Better understand the behavioral ecology of these species during foraging and feeding activities both from the surface and underwater.
  • Investigate the role played by seabirds during search and pursuit of prey and feeding activities of the mixed species groups.

Conservation and Management Implications

The Santa Monica Bay, California is an excellent site for the study of local aggregations between these marine species due to the presence of three submarine canyons and other bathymetric features that provide nutrient rich feeding areas to these animals and the species they feed upon. Monitoring these top-predator species and changes in their occurrence and distribution can provide useful data to mitigate threats to them and other organisms as well.

Some of these bathymetric features are located inside the boundaries of the newly established Marine Protected Areas. Data on these animals' aggregations may provide useful information to guide management and expansion of existing MPAs, and perhaps push the interconnectivity of existing MPA networks.



We are currently continuing our year-round monitoring of cetaceans along their coastal corridors and within and outside the boundaries of the coastal Marine Protected Areas (MPAs) in Santa Monica Bay, California. Monitoring species like cetaceans is an essential tool to:

  • Guide the planning, management, and expansion of existing MPAs
  • Justify and promote new MPAs
  • Push the interconnectivity of MPA networks



We are currently searching for funding to continue this study.
Actively support us by making a tax-deductible donation:



mixed species aggregation
Dolphins and seabirds in the Santa Monica Bay

Background - the significance of transit corridors for cetacean conservation

The waters off Los Angeles are rich in cetaceans, including threatened & endangered species like humpback and blue whales, which forage in the bay and within the local coastal MPAs. Upwelling areas near submarine canyons and escarpments in the bay are foraging hotspots and critical habitats for a variety of cetaceans as well as other species (e.g., seabirds, fish, pinnipeds).

These coastal regions also serve as regular transit corridors used by cetaceans to move between foraging hotspots. Corridors are often ignored in the design of MPAs, including those in the bay, but they are critically important to long-term population viability of these species. Protecting these migratory/movement corridors, and including them in the design, implementation and expansion of MPAs and MPA networks, is essential to ensure that the connection between critical habitats remain unbroken.

Top predators like coastal bottlenose dolphins, which are regular inhabitants of the Santa Monica Bay (SMB) and use the area as both foraging hotspot and corridor, are now considered worldwide to be key indicators and sentinels of the status and health of coastal habitats. Long-term population monitoring of these dolphins provides a powerful tool for understanding habitat use as well as tracking the progression of poorly understood diseases that may impact both cetacean and human health.

Researcher using GIS harbor seal in Malibu
Researcher using GIS to log dolphin positions   Harbor seal atop a rock in Malibu

How is data collected?

This study builds on over a decade of ecological baseline data collected by OCS utilizing already established field methodologies, existing equipment, trained research staff, and ongoing scientific collaborations with other researchers, NGO's and government agencies.

Regular boat surveys are conducted three times per month to collect systematic data on occurrence, distribution, temporal (seasonal and annual) variability, and behavior of cetaceans, as well as to monitor animal health and potential threats to them (e.g., human disturbance, marine debris, etc.), both within and outside MPA boundaries in the study area of Santa Monica Bay.

OCS research survey team follows pre-determined transects and employs GIS technology and up-to-date software to collect data and measure behavioral responses.

common dolphins

A school of common dolphins leaping off California

Project Objectives

Data on cetaceans collected along coastal corridors as well as within and outside the boundaries of the local coastal MPAs can be extremely useful for policy recommendations regarding both newly established and future protected areas.

Data on distribution, occurrence, frequency and behavior of cetaceans that frequent the SMB, where human activities and marine life overlap, will:

  • Identify aggregations of cetaceans and/or hotspots for dolphins and whales
  • Define critical marine mammal habitats near and within the newly established MPAs
  • Provide data for implementation of an overall management approach to ensure that critical habitats remain healthy and supportive of marine life
  • Establish priorities for protection
  • Create a better understanding of spatial relationships between the animals, ecological processes, and human activities
  • Identify and help control human threats to cetaceans (e.g., pollution, algal blooms, marine traffic/recreational fishing, whale watching).
  • Track the progression of poorly understood diseases relevant to both human and dolphin health
  • Help raise public support for better protection of cetaceans and the possible expansion of local MPAs using dolphins and whales as symbolic species
  • Provide guidance on enforcing, managing and evaluating the expansion of existing MPAs and help identify areas outside the current MPAs that may deserve consideration
  • Facilitate stronger collaborations with other members of the MPA network along the California coast.


We believe that MPA designation must be dynamic and that management needs to be adaptive. Research, monitoring, and evaluation must be conducted on a regular basis and, if possible, set within a more regional context. This is particularly important today, in face of climate change and other environmental issues.

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