Answer: B. reduce her demand for crew members.
Explanation: The fact that, in spite of Gertrude's significant harvest, it still has a negligible contribution to the salmon market highlights the competitiveness of the salmon market and as such Gertrude has no say or influence on the market market price of salmon.
Therefore, If the price of fresh pacific salmon were to decrease, Gertrude would most likely have to reduce it's demand for crew members so as to cut the variable cost of production(labor) , hence, stabilizing the difference in cost of production and revenue.