During the past century, the endemic range of the brook trout, Salvelinus fontinalis (Mitchill), has been extended to include western North America and the continents of Europe, Asia, Africa, and South America. Water temperature appears to be the most important single factor limiting the geographic range, but adequate precipitation and suitable spawning areas are necessary also for the establishment of self-sustaining populations. It is improbable that, with the possible exception of Asia, the present range of the brook trout will be greatly extended through further attempts at introduction.
The upstream spawning migrations of brown trout and sea trout were studied using stationary traps placed in Kirk Burn, a tributary of the upper Tweed. The sea trout spawning period extended from early November to the first week of December, while that of brown trout occurred from the middle of October to the third week of December. Sea trout were predominantly maiden spawners of ages 2.1+ and 3.1+ while brown trout were mostly age 2+ and 3+. Male-female sex ratios approximated 1:1.4 in sea trout but 6 : 1 in brown trout. Brown trout males participated in the spawning activities of sea trout. Low water conditions in Kirk Burn hindered the upstream movement of spawning sea trout, while sudden increases in water level appeared to stimulate the upstream migration of both brown trout and sea trout. The suggestion is advanced that the freshwater resident brown trout of the Tweed which migrate upstream into the smaller tributaries to spawn is wholly, or at least partially, the progeny of anadromous parents.
The study of the emcrald shiner Notropis athcrinoidcs Rafincsque Mas conducted in 1967 and 1968 in Lake Sinicoe, a eutrophic inland lake with an area of 725 ktn2 situated in the Province of Ontario, Canada. On the basis of meristic characters, the emerald shiner of Lake Sinicoe conforms to the classical description of the species and IS not distinct from the form inhabiting the Great L,akes. Annulus formation occurrcd in early June on age I fish but second and third annuli were not formed on older fish until late July through August. Young-of-the-year emerald shiners reached a total length of 45 mm by October;age 1 were 81 nun and age I1 measured 92 mm by the same month. By September, age I female emerald shiners attained a size superiority of 5 nim over males of that age group and by the end of the third summer agc II femalcs excceded age I[ males by 8 mm. Spawning occurred offshore in the latter part of July when surface water temperatures approximated 20" C. Of the three age groups, age I1 specimens were the most prevalent on the spawning grounds. Average absolute fecundity was 3410 eggs in fish of all age classes combined. Differences in water temperature seem to strongly influence the seasonal distribution pattern of the emerald shiner. The final temperature preferendurn of the species, as determined in a vertical temperature gradient tank, was 25°C. The emerald shiner is extensively utilized as a bait fish by anglers and appears to be an important forage fish. The plasticity of the species to adapt to a variety of ecological conditions and the species potcntial for high production favour its introduction to waters requiring a good converter in the food chain.
Biochemical juice attributes and color-related traits of muscadine grape genotypes have been investigated. For this study, 90 muscadine genotypes, including 21 standard cultivars, 60 breeding lines, and 9 Vitis x Muscadinia hybrids (VM), were evaluated. The biochemical properties of total soluble solids (TSS), titratable acidity, and TSS/Acid (T/A) ratio showed modest diversity among genotypes with a range of 10.3 °Brix, 2.1 mg tartaric acid/L, and 4.6, respectively. Nonetheless, the pH trait exhibited a tight range of 0.74 among the population with a minimum and maximum pH of 3.11 ± 0.12 and 3.85 ± 0.12. Color-related traits showed more deviation between individuals. Total anthocyanin content (TAC), luminosity index (L*), hue angle (h°), and chroma index (C*) displayed a range of 398 µg/g DW, 33.2, 352.1, and 24, respectively. The hierarchical clustering map classified the population into two large groups of colored and non-colored grapes based on L* and h°, suggesting the predominance of these two characters among the population. The colored berries genotypes clade was further divided into several sub-clades depending on C*, TAC, and TSS levels. The principal component analysis (PCA) separated the four-color characteristics into two groups with a negative correlation between them, L* and C* versus TAC and h°. Further, PCA suggested the positive influence of acidity in enhancing the different nutraceutical components. Despite the nature of anthocyanins as a member of phenolic compounds, a lack of significant correlation between TAC and nutraceutical-related traits was detected. The dissimilatory matrix analysis highlighted the muscadine individuals C11-2-2, E16-9-1, O21-13-1, and Noble as particular genotypes among the population due to enhanced color characteristics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.