The Caulerpa Control Protocol calls for three levels of survey intensity, based on the current status of the marine system (infected or Caulerpa free). Approved methodologies for conducting Caulerpa surveys at each level are discussed below. Other methodologies may be approved on a case-by-case basis by National Marine Fisheries Service and California Department of Fish and Game.
SURVEILLANCE LEVEL
This survey intensity level is to be used at sites not previously known to be infested with Caulerpa and at dredged material placement sites. Surveys are intended to detect large occurrences of Caulerpa that may be present at the site. A minimum of 20 percent of the bottom must be inspected. It is expected that the survey coverage will be uniformly distributed throughout the Area of Potential Effect (APE), rather than being confined to a 20 percent portion of the APE. This inspection may be completed by using SCUBA divers, remote cameras, or acoustic equipment paired with visual ground truthing. Visual surveys of subtidal APEs from the surface are not acceptable.
SCUBA
A surveillance level survey can be conducted through systematic inspection by SCUBA divers. Divers should evenly cover a minimum of 20 percent of the APE, using a compass to swim transects. Visibility conditions should be used to determine the width of the visual coverage achieved. A record should be made of the portion of the site surveyed, preferably on a site map.
Remote Camera
A surveillance level survey can be conducted using a remote camera. The camera should be towed from above at an appropriately slow speed to allow thorough examination of the bottom, using a compass or GPS to view transects that evenly cover a minimum of 20 percent of the APE. Visibility and the view width of the camera should be used to determine the width of the visual coverage achieved on each transect. A record should be made of boat speed and the portion of the site surveyed, preferably showing transects on a site map.
Acoustic Equipment
Where appropriate, sidescan sonar equipment may be used to survey the APE. The collected images should be examined for suspect returns, typically expected to appear as monotypic, low-growing vegetative patches, likely exhibiting circular colonial growth patterns. All suspect patches should be ground-truthed by a SCUBA diver or remote camera.
HIGH INTENSITY LEVEL
This survey intensity level is to be used when conducting the first of the two required surveys at sites previously identified as infected. At this level, a minimum of 50 percent of the bottom must be sub-sampled. It is expected that the survey coverage will be uniformly distributed throughout the APE. This inspection may be completed by using SCUBA divers or remote cameras, using the methods discussed above. Visual surveys of subtidal APEs from the surface are not acceptable.
ERADICATION LEVEL
This survey intensity level is to be used when conducting the second of the two required surveys at sites previously identified as infected. This is the most intensive survey level and requires that 100 percent of the bottom must be systematically inspected. This inspection must be completed by SCUBA divers. Unless the APE is very small or visibility is excellent, it is recommended that diver transects be surveyed using transect lines deployed using a GPS to ensure comprehensive coverage. This is most efficiently achieved using a team of divers. A map of the APE should be prepared showing the transects surveyed by the survey team.