Showing papers on "Fish migration published in 1981"

Latitudinal Differences in Energy Allocation and Use During the Freshwater Migrations of American Shad (Alosa sapidissima) and Their Life History Consequences

Abstract: We studied the relationships between tissue dynamics and bioenergetics of the anadromous American shad (Alosa sapidissima) homing to the St. Johns (Fla.), York (Va.), and Connecticut (Conn.) Rivers and the life history characteristics of these populations. Shad in the three populations studied differed in the degree of development of the gonads at river entry, in the absolute and relative energy allocation to reproductive products vs. migration, and in the extent of total energy depletion during the migration. St. Johns River fish consumed 70–80% of their total energy reserves to reach the spawning grounds and spawn. In this population all shad die following spawning. York River shad consumed ~30% and Connecticut River shad 40–60% of their energy reserves to migrate to the spawning grounds, spawn, and return to the sea. In these populations 25 and 35%, respectively, of the spawning adults survive to spawn again. The principal determinants of energy use were migration distance and river gradient. We reject...

Juvenile current response, growth and maturity of above and below waterfall stocks of rainbow trout, Salmo gairdneri

Abstract: Young rainbow trout were propagated from adults collected from above and below a water-fall, impassable to upstream fish migration on Kokanee Creek, tributary to Kootenay Lake, British Columbia. The two stocks of young (above and below waterfall) were reared in a hatchery under identical temperature, light and food conditions. Their directional response to water current was tested in a laboratory migration channel during their first summer and autumn. as well as the following spring. During tests in light, both stocks of young trout showed similar current responses, but in darkness the below falls stock showed much more downstream movement in the autumn than than did the above falls stock. In addition, below falls trout had a higher growth rate. were slightly heavier at the same length and matured earlier than the above falls stock. The adaptive significance of these differences are discussed in relation to maintenance of trout populations above waterfalls and to selective pressures faced by migratory below waterfall populations.

Forest Management and Anadromous Fish Habitat Productivity

Abstract: In 1976, the USDA Forest Service established a research program to study the biological, physical, and economic aspects of anadromous salmonid habitat. The Anadromous Fish Habitat Research Program is a cooperative effort involving scientists at three USDA Forest Service forest and range research stations: the Pacific Northwest at Portland, Ofegon; the Intermountain at Ogden, Utah; and the Pacific Southwest at Berkeley, California. Scientists at these facilities are studying the relationship between forest management practices and the habitat of anadromous salmonids to develop better ways to achieve concurrent production of timber, fish, minerals, livestock, and other resources. The program is oriented around three types of studies: (1) habitat requirements, (2) effects of various land uses on habitat, and (3) development of ways to improve fish habitat. The anadromous fishery resources of western North America are produced largely within forested watersheds. Eight species of anadromous salmonids including five salmon—chinook (Oncorhynchus tshawytscha), coho (0. kisutch), sockeye (0. nerka), chum (0. keta), and pink (0. gorbuscha); two trout—steelhead rainbow (Salmo gairdneri) and coastal cutthroat (S. clarki); and one char—Dolly Varden (Salvelinus malma), inhabit waters of the Pacific Northwest and Alaska. Habitat requirements of the fish are specific, and alterations of habitat by humans affects production in many ways. Forest and rangeland management activities that can influence the quality of anadromous fish habitat include timber harvest, road construction, livestock grazing, mining, water developments of various kinds, and recreational pursuits. This paper discusses some of the specific interrelationships between fish habitat and timber harvest, road construction, and livestock grazing. These three activities were selected for discussion because the USDA Forest Service is actively engaged in studies pertaining to these areas of concern. More specifically the following subjects will be discussed: ( I) effects of organic debris and its removal on fish habitat; (2) effects of mass soil movements on fish habitat; and (3) preliminary results of studies concerned with the relationship between different livestock grazing systems and fish habitat.

Metazoan parasites as indicators of movements of anadromous brook charr (Salvelinus fontinalis) to sea

Abstract: Changes in the numbers of metazoan parasites of anadromous brook charr, Salvelinus fontinalis, during the summer 1980 were determined by examining 220 fish at different times and localities in the ...

Theory and Practice of Forage-Fish Management in New England

Abstract: Several fish species serve as forage for freshwater predatory fish in New England, but only the alewife Alosa pseudoharengus and rainbow smelt Osmerus mordax have been managed extensively. Management consists of transplantation and regulation of sport, bait, and commercial fisheries. Rainbow smelt are transplanted by transfer of eggs naturally deposited on burlap bags, or by transfer of mature adults in aerated containers; alewives are established or maintained by transfer of ripe adults. Both species have anadromous populations; larval rainbow smelt migrate almost immediately to sea, but alewives remain in freshwater ponds for the first summer, where they provide food for predator fish. Landlocked populations of rainbow smelt are more valuable than those of alewives, because rainbow smelt distribution within the water column more closely matches that of most coldwater predators. Landlocked Atlantic salmon Salmo salar depend almost totally on rainbow smelt for good growth. When alewives and rainb...

Experimental sea ranching of brook trout, Salvelinus fontinalis Mitchill

Abstract: An experiment to induce anadromy in a population of wild brook trout, Salvelinus fontinalis, was conducted near Sept-Iles, Quebec, in 1978–1979. Brook trout were captured from the Matamek River, tagged and transported to the Matamek River estuary during late spring and early summer, and allowed free movement between an impassable waterfall 0.7 km upstream and the sea. Fish were recaptured in autumn as they returned to fresh water. Over two years, 34.0% of the released fish were recaptured. Best returns were in the 2+ and 3+ age classes with 38.0 and 62.1% recaptured, respectively. Straying of transplanted fish appeared to be <1%. All age classes included sea run brook trout (sea trout) but the largest percentages of sea trout occurred in older fish. Growth was better in sea trout than in fish which did not develop anadromy, presumably a function of an increased food supply at sea. Severe tagging effects stunted growth and probably suppressed anadromy, especially among younger fish. Sexual characteristics of recaptured fish indicated suppressed maturation of gonads in sea trout compared to fish remaining in fresh water and there was a shift to a larger percentage of females in the sea trout. Comparisons between our results and data on other anadromous Salvelinus species underscore the potential for sea-ranching of trout and char as a moderate effort, high yield aquaculture technique.

Landlocked Blueback Herring in Two South Carolina Reservoirs: Reproduction and Suitability as Stocked Prey

Abstract: The blueback herring, Alosa aestivalis, is an anadromous clupeid that normally does not reproduce when landlocked in freshwater and has not been widely stocked as a prey species in reservoirs. After being inadvertently stocked into Keowee and Jocassee reservoirs, South Carolina, plankton net and rotenone samples confirmed that this fish reproduced in each reservoir in 1978 and 1979. The ability to reproduce when landlocked in freshwater and the tolerance of low water temperatures are two traits that may make the blueback herring desirable for stocking as a prey species in southeastern reservoirs. However, the potential to grow beyond an acceptable prey size (about 250-300 mm total length) and to compete with other fish for food are undesirable traits that should be investigated before this fish is stocked elsewhere.

High Incidence of Scale Regeneration by Potamodromous Coastal Cutthroat Trout: Analytical Implications

Abstract: High proportions of the scales from a distinctive stock of coastal cutthroat trout Salmo clarki clarki from the Willamette Valley, Oregon were regenerated Of 122 fish, from which 50 scales each were taken, 117 (96%) showed more than 50% scale regeneration, and 48 (39%) showed more than 90% regeneration Age-growth analysis based on 3,521 samples taken from fish in 110 streams in the Willamette drainage was unsuccessful in 0 to 67% of the fish collections because of high regeneration rates If fish can be sacrificed, otoliths provide age validity equal to or better than that of scales The other external technique that does not require sacrificing fish—fin ray analysis—is extremely time-consuming and annular rings cannot always be interpreted For situations where substantial numbers of cutthroat trout cannot be sacrificed, as was the case in most of our studies, we recommend that 50 scales be taken from each fish in order to have 87% confidence that at least three of them will be nonregenerated

Passage of Large Fish Around a Causeway in Prudhoe Bay, Alaska

Abstract: Fish movements around a 2.8 km solid-fill causeway in Prudhoe Bay, Alaska, were examined by tagging anadromous least and arctic cisco (>220 mm) on each side of the causeway in summer and comparing the recapture ratios when the fish were later caught in the Colville Delta commercial fishery 80 km to the west. There was no significant difference in proportions of recaptures among fish (species combined) that did not have to swim around the causeway. Thus available data indicate that the net movements of large least cisco, and probably arctic cisco, were unaffected by this man-made coastal feature. Key words: least cisco, Coregonus sadinella , arctic cisco, Coregonus autumnalis , movements, Beaufort Sea