Quantitative genetic variation of development rate was evident among 20 half-sib and 40 full-sib families within each of two seasonally separate components of a population of pink salmon (Oncorhynchus gorbuscha) (H o : no sire effect on temperature units at hatch, P < 0.02). Differences between averages of families spawned 3 weeks apart may have had genetic or environmental sources (e.g., in constant 8°C, early embryos hatched at 606 temperature units, and late embryos, at 625). Statistical interactions between paternal effects and environment (embryos were cultured in four temperature regimes, two simulated natural regimes and two constant temperatures; H o : no sire by regime interaction effect on temperature units at hatch, P < 0.09) were weak evidence that genotype by environment interactions contributed to variation. Paternal effects in analysis of variance (evidence of additive genetic variation) were detected only at later stages. Evidences of genetic variation and of interactions between genotypes and environments are pertinent to resource conservation because they suggest that harvest management or hatchery practice have the potential to reduce genetic variation in salmon populations.Résumé : Une variation génétique quantitative du taux de développement était apparente chez 20 familles de demifrères et 40 familles de plein-frères au sein de deux composantes saisonnières distinctes d'une population de saumon rose, Oncorhynchus gorbuscha. (H o : aucun effet du père sur le nombre d'unités de température au moment de l'éclosion, P < 0,02). Les écarts notés entre les moyennes des familles dont la fécondation présentait trois semaines d'intervalle peuvent s'expliquer par des facteurs génétiques ou environnementaux (p. ex. : à une température constante de 8°C l'éclosion des embryons se produisait à 606 unités de température pour les plus hâtifs et à 625 pour les plus tardifs). Les interactions statistiques entre les effets paternels et l'environnement (embryons élevés sous quatre régimes de température, deux régimes naturels simulés et deux à température constante; H o : aucune interaction père-régime sur les unités de température à l'éclosion, P < 0,09) constituaient un indice faible du faible apport à la variation des effets de l'environnement sur le génotype. Une analyse de variance des effets paternels (évidence d'une variation génétique additive) n'a permis de mettre ces derniers en évidence qu'aux stades ultérieurs. L'existence de signes de variation génétique et d'interactions entre les génotypes et les environnements s'avère pertinente pour la conservation des ressources car elle indique que la gestion de la récolte ou les pratiques des piscicultures pourraient influer sur la variation génétique des populations de saumon.[Traduit par la Rédaction]

The goals of this study were to characterize growth of the commercially harvested red sea urchin Strongylocentrotus franciscanus in southeastern Alaska and test the validity of an aging technique. We aged urchins by counting growth rings on a part (rotula) of the Aristotle's lantern complex from urchins collected at three sites. A subset of collected urchins had three or more years of size measurements from passive integrated transponder (PIT) tag data, allowing us to fit and compare PIT tag and ring-derived growth curves and test the assumption that rings were formed annually. Growth from PIT-tagged individuals approximated the growth derived from ring counts for two of three sites. The third site deviated slightly from predicted growth, providing support for our aging technique. However, we failed to detect any extremely old urchins, suggesting that this technique is not appropriate for assessing the longevity or growth trajectory of very large urchins. An additional five sites without PIT-tagged urchins were sampled to examine spatial variation in growth. Estimates of time to fishery entry varied substantially among sites, but four nonlinear growth functions produced similar estimates at individual sites. Time to fishery entry was positively correlated with an index of food availability, which suggests that the technique revealed true variation in growth rates.

To study family-specific variation in the survival of pink salmon Oncorhynchus gorbuscha, we partitioned family size into four life history divisions: (1) maternal fecundity, (2) deposition of fertilized eggs and egg loss from the redd, (3) freshwater survival (and male potency), and (4) marine survival. We directly measured the variability in fecundity and then measured the family-specific variability of freshwater survival in several Alaskan hatchery populations. Next, we measured freshwater survival in spatially clustered groups of wild pink salmon (not identified to a specific dam or sire) in Prince William Sound, Alaska. Drawing on estimates of the family-specific variation of marine survival in pink salmon from previous studies, we concluded that family-specific egg deposition processes and family-specific variability in the marine environment were the primary sources of the overall variability in pink salmon family size, at least in the populations studied. We hypothesize that the freshwater environment generally induces lower variability in family size than does the marine environment. If this is so, it appears that pink salmon populations are more finely adapted to the freshwater environment, presumably because this environment is more constant. Finally, we speculate that the marine environment is too unpredictable to permit the same level of adaptation of many traits closely linked to marine survival.

Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications have used some of these data but some data have appeared only in graduate theses or the gray literature. There also are data that have never appeared outside original data sheets. Motivation for studies has included fisheries management and environmental monitoring of sewer and power plant outfalls as well as changes associated with disease epidemics. Studies also have focused on kelp restoration, community effects of sea otters, basic sea urchin biology, and monitoring. The data sets presented here are a historical record of size, density, and growth for a common group of marine invertebrates in intertidal and nearshore environments that can be used to test hypotheses concerning future changes associated with fisheries practices, shifts of predator distributions, climate and ecosystem changes, and ocean acidification along the Pacific Coast of North America and islands of the north Pacific. No copyright restrictions apply. Please credit this paper when using the data.

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