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Haley, N., J. Boreman, and M. Bain. 1996. Juvenile Sturgeon Habitat Use in the Hudson River. Pp. 1-18 in Final Reports of the Tibor T. Polgar FellowshipProgram. Hudson River Foundation, NewYork. Misho Borissov Dr. Lin’s Seminar 475 For Monday of April. Background (continued).

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Haley, N., J. Boreman, and M. Bain. 1996. Juvenile Sturgeon Habitat Use in the Hudson River. Pp. 1-18 in Final Reports of the Tibor T. Polgar FellowshipProgram. Hudson River Foundation, NewYork.Misho BorissovDr. Lin’s Seminar 475For Monday of April


Background (continued)

  • Oligohaline – intermediate freshwater/saltwater zone

  • Mesohaline – saltwater region


Historical Background

  • Atlantic Sturgeon

    • Acipenser oxyrinchus

  • Short-nose Sturgeon

    • Acipenser brevirostrum

  • Hudson River

    • History of the Hudson River


  • Experimental Background

    • Tappan Zee Bridge

      To Staatsburg, New York

    • Four Strata used

      • Wide Estuary

      • Highland Gorge

      • Wide River

      • Narrow River


    Additional Background

    • Wide Estuary

      • Widest Section of the estuary. Channel of uniform depth

    • Highlands Gorge

      • Narrowest and Deepest section of the estuary.

    • Wide River

      • Widest, freshwater portion of the estuary.

    • Narrow River

      • Region consists of a straight, featureless channel. Channel and river width are nearly equal with very narrow subtidal banks along the shoreline.


    Experimental Background(continued)

    • Nets placed @ each stratum

      • Three small nets in hopes of capturing juvenile sturgeon

  • Juvenile terms

    • Atlantic sturgeon

      • Less than 1200 mm

  • Short-nose sturgeon

    • Less than 510 mm


  • Results gathered

    • 57 Juvenile Sturgeon caught

      • 36 wild Atlantic sturgeon

      • 12 Short-nose juvenile sturgeon

      • 09 Stocked Atlantic sturgeon


    Results(continued)

    • Total Length (mm) Weight (g)

    • Range Range

  • Short nose404-584 300-1200

  • Atlantic 272-1245 80-4940

  • Stocked 306-659 120-2030


  • Sturgeon Distribution

    • Distribution amongst the four strata

      • Atlantic sturgeon - Distributed along all four strata

      • Short-nose sturgeon- distributed along all four strata.

      • Stocked sturgeon – found only in the Wide River and the Narrow River strata


    Graph 1 for result # 1


    Graph 2 for Result # 1


    Other experiments within this result

    • Wild Atlantic sturgeon with a length of less than 600 mm was used.

      • Scientists did because of the wide range of distribution between sturgeon

        • They compared the distribution of an Atlantic Sturgeon less than 600 mm with the distribution of the Short-nose and Stocked sturgeon.


    Graph 1 for Result # 2


    Salinity

    • Saltiness measured with YSI model 5500 Salinity meter.

      • Short-nose Sturgeon

        • Found mostly in freshwater

    • Atlantic Sturgeon

      • Found mostly in salt water

  • Stocked Sturgeon

    • Found in three zones

      • Found in salty, sweet, and intermediate zones


  • Salinity Graph


    Salinity Graph # 2

    • Wild Atlantic Sturgeon

    • Different salinity and

    • temperature measure-

    • ments in HG to see if

    • seasonally-variable

    • characteristics are a factor

    • in surgeon distribution

    • and occurrence

    By following the red line

    At each strata, one would

    Notice that salinity levels

    Stayed nearly constant

    Throughout the summer


    Salinity conclusion – All three exhibited different distributions in terms of the salinity level.

    • Distribution according to saltiness

      • Short-nose Sturgeon

        • As reported, short-nose sturgeons were found primarily in the freshwater region

      • Atlantic Sturgeon

        • These were found primarily in the saltwater region

      • Stocked Sturgeon

        • These were found in the intermediate zones


    Silt, Sand, & Gravel

    • Silt

      • Rock and Soil

  • Sand

  • Gravel

    • Stone and Sand


  • Silt, Sand, & Gravel

    SUBSTRATE% of Effort SNS ASSS

    silt80.4 11 34 9

    sand17.4 1 2 0

    gravel2.3 0 0 0

    significance 1.03 4.612.20


    Depth and Temperature

    • Temperature and Depth Measurement

      • Measured with YSI Model 5500 Temperature meter and depth

    Depth Temp. (July)Temp (Aug)

    Short-nose17.324.227.5

    Atlantic22.82726.6

    Stocked16.6(around)2626.9


    Frequency of Occurrence

    • Sampled Depths to see in which range the sturgeon would appear.

      • Different depths were taken into consideration as well as which sturgeon was caught in that respective depth


    Depth Frequency Graph

    SHORT NOSE ~~>

    WILD ATLANTIC ~~>

    STOCKED ATLANTIC ~~>


    Finale

    • The Wild Atlantic Sturgeon were primarily in the Highlands Gorge stratum (deep salty region)

    • The Short nose Sturgeon were primarily found in the Narrow River stratum (freshwater zone)

    • In saltier regions, AS outnumber SNS by 10:1, while in freshwater regions, that ratio is reversed, thus concluding that freshwater/saltwater boundary may serve as an ecological barrier between these two species.


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