World Aquaculture September 2018

58 SEP TEMBER 2018 • WORLD AQUACULTURE • WWW.WA S.ORG abilities. They spend up to seven years as larvae burrowed into the beds of streams and rivers where they consume microscopic debris filtered from the water. When they eventually leave the safety of the streambed, they must not only transform their entire bodies by developing eyes, a newmouth, teeth and a silvery body, but they must also be able to persist in the saline waters of the Pacific Ocean and grow to adulthood on a diet of blood. After spending a few years attached to host fish and marine mammals in the Pacific Ocean, adults must return to freshwater where they must survive for one or two more years as they prepare to spawn. Adults can make spawning migrations as far inland as T he Pacific lamprey Entosphenus tridentatus is one of the oldest native fish in the Pacific Northwest, USA. At an estimated 450 million years old, these lampreys have seen many other species come and go from the earth. Despite their ability to persist through numerous global mass extinction events, the Pacific lamprey is currently a species of concern in response to reductions in range and declines in abundance that have occurred within the last century due mainly to habitat destruction, dams and other barriers to passage (Close et al. 2002, Moser and Close 2003, Moyle et al . 2009). Not only is their tenure on this planet impressive, but this species displays a staggering number of unique qualities, traits and FIGURE 2. Experimental tanks used in temperature trials, with aerated head boxes and packed columns for degassing and aeration (Photo: James Barron). Optimization of Culture Temperatures for Larval Pacific Lamprey James M. Barron, Racheal R. Headley, Kelli A. Hawke, John S.A. Holmes, Ashley Carr, Katherine Strailey and Ann L. Gannam FIGURE 1. In-line heaters with mixing cells were used to warm three of the treatment temperatures above the ambient groundwater temperature (Photo: James Barron).