DOI: 10.5061/dryad.917t14q
title: Data from: Maintaining a wild phenotype in a conservation hatchery program for Chinook salmon: the effect of managed breeding on early male maturation

description: In many salmonid species, age and size of maturation is plastic and
 influenced by the interaction between genetic and environmental factors.
 Hatchery reared salmon often mature at an earlier age and smaller size
 than wild fish. Modern salmon conservation efforts have focused on
 managing the level of gene flow between hatchery and natural origin fish
 to minimize potential genotypic and phenotypic change. In salmonids,
 maturation probability is dependent on exceeding a genetically set
 threshold in growth rate and energetic status (and by association body
 size) referred to as the probabalisitic maturation reaction norm (PMRN).
 Over fourteen years, we monitored the frequency of age-2 precocious male
 maturation (common term: minijack rate) and the PMRN of a natural founder
 (FNDR), integrated natural-hatchery (INT), and segregated hatchery (SEG)
 broodlines of spring Chinook salmon, Oncorhynchus tshawytscha. The average
 minijack rate (± SEM) of the FNDR, INT and SEG broodlines was 48.2 ± 5.2%,
 41.9 ± 3.6% and 30.9 ± 4.7%, respectively. Additionally, the PMRN WP50
 (predicted weight at 50% maturation) of the SEG broodline was
 significantly greater (20.5 g) than that of the FNDR/INT broodline (18.2
 g). We also conducted a common garden experiment exploring the effects of
 less than one [INT (0-1)], one [SEG (1)] or two [SEG (2)] generations of
 hatchery culture on the minijack rate and PMRN WP50 . Growth was not
 significantly different among broodlines, but minijack rates were
 significantly lower following two consecutive generations of hatchery
 culture: [INT (0-1): 68.3 ± 1.7%], [SEG (1): 70.3 ± 1.8%] and [SEG (2):
 58.6 ± 0.4%] and the PMRN WP50 was significantly higher by 6.1 g after two
 generations of SEG culture. These results indicate that managed gene flow
 reduces phenotypic divergence, but may serve to maintain potentially
 undesirable high minijack rates in salmon conservation hatchery programs.
description: CESRF_broodstock_crosses_1997_2011This file contains information on the crosses resulting from adult Chinook salmon used for broodstock at Cle Elum Supplementation and Research Facility, Cle Elum, Washington for brood years 1997 through 2011.ClarkFlat_BroodYears_1998_2001_MJScreen_DataThis file contains data for all individual Chinook salmon juveniles sampled during minijack assessments at Clark Flat acclimation site for brood years 1998 through 2001, including gender, size and maturation status of males.ClarkFlat_BroodYears_2002_2011_MJScreen_DataThis file contains data for all individual Chinook salmon juveniles sampled during minijack assessments at Clark Flat acclimation site for brood years 2002 through 2011, including gender, size and maturation status of males.GJ_Maturation_Data_MalesThis file contains information on individual male Chinook salmon (including size and maturation status) for each of the three broodlines (eggs were obtained from the Cle Elum Supplementation and Research Facility, Cle Elum, Washington) reared in the common garden experiment conducted at the Northwest Fisheries Science center, Seattle, Washington.