Forage fish represent a critical link in the marine food web by supporting numerous species of sea birds, marine mammals and other commercially important fish including chinook and coho salmon. Hypomesus pretiosus (Girard 1855), commonly known as the surf smelt, is one of the least-studied forage fish. Surf smelt not only support other marine life but also make up a considerable commercial and recreational fishery for human consumption in Washington State. In general, fish are highly sensitive to changes in their environment during their early egg and larval stages. Understanding how climate change stressors are going to impact young fish development is vital to creating effective management plans.

The purpose of this research, conducted in partnership with the Washington Department of Fish and Wildlife’s forage fish team, was to examine how surf smelt eggs and larvae respond to elevated seawater temperatures and acidification. The results of this project depicted that even though the eggs of the surf smelt appear to be robust to changes in temperature and acidity, the larvae use their energy supplies significantly faster while under temperature stress. The observed high rate of energy loss reduces the time larval surf smelt have before needing to actively forage. Losing this time can inhibit their ability to make it to the large patches of food for proper larval development. The results of this research indicate that rising seawater temperatures may pose a serious threat to this important forage species during a critical life stage.