Figure 1. Primary Productivity Mean for the Monterey Bay, Gulf of the Farallones, and Cordell Bank National Marine Sanctuary. [View Larger]
The upper portion of the epipelagic zone receives sunlight that drives photosynthesis in microscopic floating plants called phytoplankton, which form the base of the complex and diverse open-ocean food web.
The open-ocean habitat in these sanctuaries is strongly influenced by the oceanographic patterns of the northern California coast - such as upwelling, which occurs in the spring and summer and fuels phytoplankton blooms. Coastal upwelling, which occurs within roughly 45 to 50 kilometers (28 to 31 miles) of shore, does not occur uniformly. For example, there are two upwelling centers in Monterey Bay National Marine Sanctuary: one near Point Año Nuevo and one south of Point Sur. There is one such center north of Cordell Bank National Marine Sanctuary, near Point Arena, that influences oceanographic conditions within the sanctuary.
InhabitantsThe productivity in the open ocean, driven by the infusion of nutrients from upwelling, sustains dynamic marine systems in the sanctuaries. The phytoplankton blooms feed zooplankton and some planktivorous fishes such as anchovies and sardines. Zooplankton (such as larvae, copepods, krill and jellies) are eaten by a wide variety of large, highly mobile animals, including squid, fishes, sea turtles, seabirds and mammals.
A mother Humpback whale (Megaptera novaeangliae) and her calf "lunge-feed" on krill in Monterey Bay. Note that you can actually see the balleen in both animals. The balleen is used like a seive to allow the whale to push water out, but keep the krill in.
The Great White Shark (Carcharodon carcharias) is one of the most-feared predators in the sea, but has more to fear from man. Copyright Monterey Bay Aquarium. Photo taken by Steve K Webster.
In terms of sheer number and diversity, invertebrates rule the region's open waters. These spineless creatures - including the euphausiid shrimp (krill) and copepods, make up about 95 percent of all described animal species.
Conservation and Management IssuesMany human activities, such as commercial vessel traffic, motorized personal watercraft, whale watching and aircraft overflights, have the potential to harm or disturb the natural behavior of open-ocean animals. Other issues include:
- Non-point source pollution: Water quality in offshore regions can be threatened or affected by large or continuous discharges from the shore, spills by vessels, illegal dumping activities or residual contaminants from past dumping activities.
- Oil: Oil and other discharges from sunken vessels as well as illegal discharges from oil tankers and cargo vessels have negatively affected marine organisms from time to time. The threat of an offshore spill is constant.
- Marine debris: Plastic, in particular, is a worldwide problem. Marine wildlife may ingest plastic particles or become entangled in plastic debris.
- Introduced species: These "invading" organisms, which are often transported on commercial and recreational vessels and other vectors, are a concern because they can out-compete native species for space and other resources.
- Harmful algal blooms: A rapid increase in algal species can produce extremely potent toxins, which can cause injury or death to other organisms.
MonitoringIn some cases, monitoring efforts span multiple sanctuaries. For example, the Tagging of Pacific Pelagics (TOPP) ) and CSCAPE studies involve all three northern California sanctuaries. In another example, both Gulf of the Farallones and Monterey Bay sanctuaries are involved in the Wind to Whales project.
Many other monitoring projects focus on the open ocean. Other examples, by sanctuary, include:
- Distribution and Abundance of Marine Birds, Mammals and Zooplankton Relative to the Physical Oceanography of the Gulf of Farallones and Cordell Bank
- Cordell Bank Ocean Monitoring Program
- Cordell Bank Oceanographic Buoy
- Sanctuary Ecosystem Assessment Surveys (SEA Surveys)
- Monitoring Harmful Algal Blooms (HABs)
- Monitoring the Open Water Community over the Monterey Submarine Canyon