Cascadia Research has launched an ambitious three-part research expedition off Central America to discover new information on the breeding grounds of humpback and blue whales (see Scientific Background). The objectives of the expedition (see Objectives) for blue whales include determining the location of the winter mating and calving areas used by blue whales in the North Pacific and conducting the first directed study on the behavior of these animals on their wintering grounds. For humpback whales, we will conduct the first survey to determine the number and use of coastal waters of Central America as a mating and calving ground for North Pacific humpbacks. The trip is divided into three separate legs each with separate research objectives and methods.

Leg 1: 13 January to 8 February 1999, Mexico to Costa Rica.
 

We will survey for blue whales 1,000 miles west of Costa Rica across an oceanographic feature called the Costa Rican Dome. This is an area of high productivity that is suspected to be the mating and calving (and possibly feeding) area for blue whales in the eastern North Pacific.
 

Methods we will use to study blue whales include:

1. Photographic identification - We will take photographs of the unique natural markings on the side of blue whales. We have identified more than 1,000 unique blue whales using this technique off California and Mexico.
2. Sampling of skin for genetic analysis - We will collect samples of sloughed skin from the wake of blue whales to allow determination of sex and genetic relatedness to other populations.
3. Acoustic monitoring - We will use a hydrophone (underwater vocalizations) to determine what sounds blue whales are making on their mating grounds and if there are sex differences in these vocalizations.
4. Hydro-acoustic survey - We will use a sophisticated underwater sonar system to map and record the presence of any prey of blue whales (krill).
5. Monitoring underwater behavior of whales - We will attempt to attach (using a suction-cup) a small instrument package (critter-cam) to a blue whale for a few hours that would film what the whale is doing, record
6. vocalizations, and monitor how deep the whale is diving. This package has been developed by National Geographic Television and its use is part of our work with them.

This leg will focus on surveying all Central American Pacific coastal waters to determine the use of these areas as a mating and calving ground for humpback whales. Preliminary research conducted by Cascadia Research has revealed that North Pacific humpback whales utilize
southern Costa Rica as a breeding area. This is much farther south than any of the other three known North Pacific breeding grounds (Mexico, Hawaii, and Japan). We have documented that most of these animals are coming from feeding grounds off California.

Methods we will use to study humpback whales on this leg include:

1. Photographic identification - We will take photographs of the natural markings on the underside of the flukes of humpback whales. We will compare these to the more than 900 animals we have identified off  California as well the collections maintained by other researchers from throughout the North Pacific.
2. Acoustic monitoring - We will use a hydrophone to record the unique and mysterious song sung by male humpback whales. These songs are useful for comparison to other breeding grounds of humpback whales.
3. Behavior monitoring - We will study the behavior of humpback whales to determine if they are mating and calving in these waters.

This leg will be used to study both humpback and blue whales along the coast of Mexico and especially along the west coast of Baja. Our work is being done in collaboration with two researchers based in Mexico; Jorge Urban and Diane Gendron.