The major objectives of the Gulf of Alaska Expedition are to use DNA to identify the stock specific rearing areas for all five species of salmon and determine their abundances and their condition. This is the first time that this information will be available and it will be shared with the general public. All science advances by testing hypotheses and the main hypothesis for this expedition is that abundance is mostly determined by the end of the first ocean winter, meaning most of the ocean mortality has occurred by the end of the first ocean winter. Included in this hypothesis is an interpretation that the individuals that grow faster in the first few months in the ocean are the fish that survive better.

Other objectives are to determine the amount of food available for salmon in the winter to be able to assess the impact of hatchery fish on wild fish, assess the impact of the ocean warming events of food production, assess the health of salmon and identify common diseases. It is known that food for salmon is the lowest in the winter and assessing the food abundance at the end of the winter provides an indication of the amount of salmon that could survive in the Gulf of Alaska.

The Gulf of Alaska Expedition will be the first comprehensive study of the stock abundance, composition and condition of all stocks of all species of Pacific salmon at the end of their first ocean winter. The expedition will use the experience and knowledge of the 21 researchers from all Pacific salmon producing countries and a highly experienced crew to study salmon and the components of their ecosystem. Surveys of abundance and condition of salmon in their first winter-at-sea are a logical extension of the early marine survival studies conducted in many nearshore marine areas along the northwest coast of North America. This expedition will be an example of the opportunities to coordinate international research with a focus on discovering the mechanisms regulating production through international collaboration.