conspecifics are likely replacing the wild populations of both taxa, raising concerns about the viability and persistence of wild stocks (Quiñones, unpublished data). Steelhead trout Steelhead are the anadromous form of rainbow Two distinct life history O. mykiss. patterns are recognized in the Klamath River basin: winter, and summer steelhead trout (). Winter steelhead trout move upstream after the onset of winter rains between November and April, shortly before spawning. Summer steelhead trout move upstream from April to June, spend the summer months in deep pools while they mature and spawn from December to April. Life histories differ in smolt age, length of marine residency, and patterns of reproduction (). Steelhead trout adults are capable of spawning once a year but often spawn every other year, up to four times. Most adults become reproductively mature from age 1 to 5 (). Juveniles will spend one to two years in cold fast-flowing perennial streams and are often associated with riffle habitats. Trends of adult Iron Gate Hatchery steelhead and Salmon River summer steelhead trout are in steep decline (Quiñones, unpublished data) and appear to be on the brink of extinction (). Figure 3.1. Klamath River basin, California and Oregon. Methods Conceptual To synthesize our hypotheses, we first constructed a conceptual model of variables potentially driving Pacific salmon abundances, based on peer-reviewed literature (discussed in the Introduction section; Figure 3.2). The variables were divided into three categories, those that affect internal population dynamics (population variables), climatic conditions (climate variables), and fresh water habitat quality (habitat variables). We recognize that factors interact with one another, within and among categories. Their interactions are investigated in our analysis described below. However, we organized the factors in the conceptual model to facilitate initial
conspecifics are likely replacing the wild populations of both taxa, raising concerns about the viability and persistence of wild stocks (Quiñones, unpublished data). Steelhead trout Steelhead are the anadromous form of rainbow O. mykiss. Two distinct life history patterns are recognized in the Klamath River basin: winter, and summer steelhead trout (). Winter steelhead trout move upstream after the onset of winter rains between November and April, shortly before spawning. Summer steelhead trout move upstream from April to June, spend the summer months in deep pools while they mature and spawn from December to April. Life histories differ in smolt age, length of marine residency, and patterns of reproduction (). Steelhead trout adults are capable of spawning once a year but often spawn every other year, up to four times. Most adults become reproductively mature from age 1 to 5 (). Juveniles will spend one to two years in cold fast-flowing perennial streams and are often associated with riffle habitats. Trends of adult Iron Gate Hatchery steelhead and Salmon River summer steelhead trout are in steep decline (Quiñones, unpublished data) and appear to be on the brink of extinction (). Figure 3.1. Klamath River basin, California and Oregon. Methods Conceptual To synthesize our hypotheses, we first constructed a conceptual model of variables potentially driving Pacific salmon abundances, based on peer-reviewed literature (discussed in the Introduction section; Figure 3.2). The variables were divided into three categories, those that affect internal population dynamics (population variables), climatic conditions (climate variables), and fresh water habitat quality (habitat variables). We recognize that factors interact with one another, within and among categories. Their interactions are investigated in our analysis described below. However, we organized the factors in the conceptual model to facilitate initial
Quinones_Recovery_of_Pacific_Salmonids.docx