e~p o r t , OR 97365, &rYA BERNARD, D. R. 1981. Multivariate analysis as a means of comparing growth in fish. Can. J. Fish. Aquat. Sci. 38: 233-236.The Hotelling's T~ is described as a test for differences between like von Bertalanffy growth parameters estimated from two fish groups when these parameters are correlated.Equations to calculate 7 " ' are presented as are equations to modify T2 to an F statistic for use in testing. Simultaneous confidence intervals and critical F values are described to separate effects of parameters on observed differences in growth. Assumptions made by the T2 technique are discussed, as are ways in which any bias caused by violating these assumptions is lessened. Two numerical examples concerning growth differences among groups of Pacific ocean perch (Sehastes alutus) are provided. Growth of male and of female perch captured off the Columbia River is different with L, being the most statistically significant parameter and P, the Beast. Growth of male perch captured off Vancouver Island and off the Columbia River is also different with only L, statistically significant. , 1981. Multivariate analysis as a means of comparing growth in fish, Can. J. Fish. Aquat. Sci. 38: 233-236. Le prksent article contient une description du T2 de Hotelling comme test des diffbrences entre paramGtres de croissance de von Bertalanffy semblables estimts chez deux groupes de poissons et quand ces parametres sont reliCs. On y resente les Cquations servant B calculer P T' ainsi que les Cquations pernettant de modifier T en une statistique F pour usage dans le test. On dCcHit les intervalles de confiance simultanks et les valeurs critiques de I: afin de siparer les effets des paramktres sur Ies differences de croissance observkes. Les hypothises sous-tendant la technique du T2, ainsi que les moyens d'attknuer tout biais pouvant risulter de la violation de ces hypothkses sont examinbs. Deux exemples numkriques de differences de croissance p a m i des groupes de sChastes B longue michoire (Sebastes ctfutu.~) sont prQentCs. Les &bastes miles et femelles capturis au large dm fleuve Columbia diffkrent dans leur croissance, H , , Ctant le parametre le plus significatif i l'analyse statistique et to, le parametre le moins significatif. La croissance des sCbastes m3es capturbs au large de I'ile Vancouver et au Iarge du Weuve Columbia differe Cgalement, L, seul Ctmt statistiquement significatif.

Pacific salmon hatcheries support important commercial fisheries for Pink Salmon Oncorhynchus gorbuscha and Chum Salmon O. keta in Prince William Sound (PWS), Alaska. State policy mandates that hatchery-produced fish must not negatively impact natural populations, which can occur during mixed fisheries and via ecological and genetic interactions. Therefore, we quantified the spatial and temporal overlap of natural-and hatcheryorigin salmon (1) as they migrated into PWS and (2) in PWS spawning streams. Intensive sampling during 2013-2015, combined with ancillary agency harvest and hatchery composition data, also allowed us to estimate the hatchery, natural, and total run sizes. Estimated annual proportions (SE in parentheses) of hatchery fish in the preharvest run ranged from 0.55 (0.01) to 0.86 (0.03) for Pink Salmon and from 0.51 (0.03) to 0.73 (0.02) for Chum Salmon. Proportions of hatchery fish across all sampled PWS spawning streams were much lower, ranging from 0.05 (0.03) to 0.15 (0.07) for Pink Salmon and from 0.03 (0.03) to 0.09 (0.03) for Chum Salmon. In both species, relatively high instream proportions of hatchery fish tended to be geographically localized, while many streams exhibited low proportions. The estimated total PWS runs were 50-142 million Pink Salmon and 2.3-5.4 million Chum Salmon. Commercial fisheries harvested 94-99% of hatchery-origin fish of both species, 27-50% of natural-origin Pink Salmon, and 17-20% of natural-origin Chum Salmon. Despite very high harvest rates on hatchery-produced fish, an estimated 0.8-4.5 million hatchery Pink Salmon and 30,000-90,000 hatchery Chum Salmon strayed into PWS spawning streams. Our findings provide context for further research on the relative productivity of hatchery-and natural-origin salmon spawning in streams, density-dependent survival, improvements in fidelity to hatchery release sites, the influence of hatchery production on escapement management and policy, and refinements in harvest management precision in PWS.

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From 1985 through 1987, the efficacy of baited, rigid hoop traps for catching burbot Lota lota was tested in several lakes and the Tanana River in central Alaska. Experiments were conducted on the diurnal catchability of burbot, optimal baiting strategies, retention of burbot, optimal duration of soak, condition of captured burbot, size of hoop traps, recruitment to the gear, and capture‐induced behavior of burbot. Baiting was needed to capture burbot. Once caught, burbot rarely escaped the gear. Burbot held in hoop traps set in lakes maintained their condition for days; condition of burbot held in rivers deteriorated after the first day of captivity. Rebaiting hoop traps daily improved catches in lakes, but not in the river. For once‐baited sets, optimal soaks were 2 d in lakes and 1 d in the river. Hoop traps of different sizes caught burbot of similar sizes in lakes, but large traps caught slightly larger fish in the river. Burbot were fully recruited to hoop traps usually at 450 mm total length or longer, although considerable numbers of smaller fish were captured in lakes and the river. Fully recruited burbot exhibited no temporary, trap‐induced behavior 2—3 weeks after capture.