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Science 19 December 2008:
Vol. 322. no. 5909, p. 1790
DOI: 10.1126/science.1156578
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Technical Comments

Response to Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon"

Martin Krkosek1,2*{dagger}, Jennifer S. Ford3, Alexandra Morton4, Subhash Lele1 and Mark A. Lewis1,2

1 Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada.
2 Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
3 Ecology Action Centre, Halifax, NS, Canada.
4 Salmon Coast Field Station, Simoom Sound, BC, Canada.


Figure 1 Fig. 1. Plot of the Ricker map n(t) = n(t – 2)exp [r – bn(t – 2)] parameterized by pre-infestation (1970 to 2001) escapement data for Broughton Archipelago pink salmon [n(t) is an escapement estimate in year t normalized by its time-series mean (2)]. The dotted line is the 1:1 line showing the carrying capacity at the intersection with the Ricker curve. Overcompensation occurs where the curve has negative slope, indicating that high spawner abundance leads to low returns. Comparison with figure 3 in (2) shows that pink salmon were commonly in the overcompensatory regime, including the exposed infested group. [View Larger Version of this Image (8K GIF file)]
 

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Science. ISSN 0036-8075 (print), 1095-9203 (online)