Thiamine Deficiency in California Salmon

As female salmon returned to freshwater spawning grounds with low levels of this essential vitamin, they provided insufficient thiamine to their eggs, inhibiting proper development. This led to increased mortality rates among juveniles in hatcheries, with surviving fish exhibiting symptoms of TDC, such as erratic swimming and lethargy.

In response, a collaborative effort involving multiple agencies began to investigate the prevalence and impacts of thiamine deficiency in California salmonids. <p>To assess thiamine deficiency and its effects over time, egg thiamine levels have been systematically measured at various hatcheries in central and northern California. Unfertilized eggs from mature Chinook salmon (<i>Oncorhynchus tshawytscha</i>), Steelhead trout (<i>Oncorhynchus mykiss</i>), and coho salmon (<i>Oncorhynchus kisutch</i>) were collected across California to measure thiamine concentrations.