Laboratory-bred Longfin Smelt produced offspring in the first year in captivity

Longfin Smelt, Spirinchus thaleichthys, is an imperiled migratory forage fish that is endemic to the west coast of North America. The southernmost distinct population in the San Francisco Estuary, in particular, has experienced dramatic declines in abundance over the past few decades. Diverse strategies are likely needed for effective conservation of Longfin Smelt, with captive breeding and rearing likely to become essential for enhancing population size and preserving genetic diversity. Only recently have significant investments been made to develop a culture program for Longfin Smelt. Here, we report the first successful rearing of laboratory-bred (F1) Longfin Smelt to maturity (at age-1+), followed by the subsequent spawning and production of a second generation (F2) of Longfin Smelt, entirely within captivity. We also describe the culture conditions utilized throughout the complex life cycle of the mature F1 broodstock.