Feasibility of Fish Passage at Alameda Creek Diversion Dam

Feasibility of Fish Passage at Alameda Creek Diversion DamBased on other values reported in the literature, it is assumed that the egg to fry survival rate, S 1 , is14 percent; ocean survival, S 3 is 20 percent per year; and that migration to spawning ground survival,S 4 is a product of both the reported 80 percent , and an estimated 90 percent survival rate fromhandling and transport through facilities and devices. Using these estimates for survival during keylife stages and equations (1) and (2), the number of returning adults from initial population of at least100 breeding pairs (i.e., 100 females) can be estimated as,N2[( 5,000) ⋅ ( 0.14) ⋅ (.07) ⋅ ( 0.20 ) ⋅ ( 0.80) ⋅ ( 0.90)] ⋅100141t+ 1==Of the estimated 141 returning adults produced from the initial 100 females, it is uncertain whatproportion would be male or female. However, if we assume that the sex ratio is 1:1 there would beapproximately 70 females to produce eggs for the next generation. However, since the rate ofpopulation growth, λ, is dependent only on life stage survival rates, the number of individuals in thepopulation would continue to increase (i.e., λ = 1.41).These generalized estimates are presented to illustrate that, in theory, fish passage at ACDD couldpotentially produce a sufficient number of returning adults if sufficient adult spawning and juvenilerearing habitat is available to accommodate 100 breeding pairs.ACDD Passage June 2009 Page C-2