This project was part of a larger international project (SPLASH) designed to estimate the abundance and determine the population structure for humpback whales throughout the North Pacific involving the governments of Canada and Mexico as well as multiple agencies within the government of the U.S. The primary study methods were photo-identification and biopsy sampling. Passive acoustics were used to aid in finding aggregations of whales. In addition, biological and oceanographic data were collected to better characterize the whale’s environment, and survey data were collected for all other cetacean and pinniped species observed. Biopsy samples were also taken from other cetacean species, primarily in areas where they have been poorly sampled in the past. The Hawaiian Island Humpback Whale Sanctuary (HIHWS) collaborated on this cruise by sending two skilled photographers on each leg of survey effort. The U.S. Navy collaborated on this cruise by funding the acoustic and oceanographic sampling.
This is a collaborative research effort by an international team of scientists, including researchers from Southwest Fisheries Science Center (SWFSC) and research colleagues from Mexico, to improve methods to detect and estimate abundance of the critically endangered vaquita, or Gulf of California harbor porpoise.
In 1986 the U.S. National Marine Fisheries Service (NMFS) initiated a long-term, large-scale research program to monitor trends in the abundance of dolphin populations in the eastern tropical Pacific (ETP).
In 1997, the Southwest Fisheries Science Center (SWFSC) conducted a survey designed to estimate the abundance of vaquita, the Gulf of California harbor porpoise (Phocoena sinus). This was a joint project between the fisheries agencies of the United States and Mexico.
The Stenella Abundance Research Project (STAR) is a multi-year cetacean and ecosystem assessment study designed to assess the status of dolphin stocks which have been taken as incidental catch by the yellowfin tuna purse-seine fishery in the Eastern Tropical Pacific.
The California Current Cetacean and Ecosystem Assessment Survey (CalCurCEAS) is a marine mammal assessment survey of the U.S. West Coast waters. Similar research in this geographic area was conducted under the name of ORCAWALE (for Oregon, California, and Washington Line-transect Experiment) in previous years.
This study was conducted in Mexico aboard the National Oceanographic and Atmospheric Administration (NOAA) research ship McArthur during two months in summer/fall 1995. The primary purpose of this research was to learn how to better estimate the abundance of long-diving whales during ship line-transect surveys. These whale species, including beaked whales and dwarf and pygmy sperm whales, dive for such long periods of time that there is a high probability that they will never surface within the visual range of observers searching from a moving survey vessel with 25X binoculars. The project was called CADDIS (Cetacean Acoustic Detection and Dive Interval Studies) and focused on two potential approaches to improve abundance estimates: 1) acoustic detection of diving animals, and 2) collecting dive interval data on those species to serve as a basis for a model-based abundance correction factor. The CADDIS research was conducted primarily in the southern Gulf of California, Mexico. This area was chosen for two main reasons: prior surveys showed the area to have a very high density of small long-diving whales of the genera Mesoplodon, Ziphius and Kogia (Mangels and Gerrodette 1994), and the area has consistently calm seas which enables dive intervals to be observed and accurately measured. The timing of the survey was similarly chosen as the season with the consistently lowest winds in the southern Gulf.