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Ai Tshort


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Ai Tshort

  1. 1. <ul><li>Asian Institute of Technology </li></ul><ul><li>SERD </li></ul><ul><li>Seminar </li></ul><ul><li>Jed Brown </li></ul><ul><li>Fisheries and Wildlife Division </li></ul><ul><li>District Department of the Environment </li></ul><ul><li>Washington, DC </li></ul><ul><li>USA </li></ul>
  2. 2. Outline <ul><li>Biography/Background </li></ul><ul><li>Coastal/anadromous fish </li></ul><ul><ul><li>Species </li></ul></ul><ul><ul><li>Status and problems </li></ul></ul><ul><li>Navigation—vessel strike mortality in Atlantic sturgeon </li></ul><ul><li>Coastal fish habitat degradation from invasive species </li></ul><ul><ul><li>Common reed phragmites (wetland plant) </li></ul></ul><ul><li>Dams—fish passage and trade-offs with hydropower </li></ul>
  3. 7. University of Arizona <ul><li>Tested the feasibility of using halophytes (salt-tolerant plants) to remove nutrients (nitrogen and phosphorus) from saline aquaculture effluent </li></ul><ul><li>Halophytes being domesticated for production of oil seed, forage </li></ul><ul><li>Conducted mass balance experiments using draining lysimeters (soil-filled containers) </li></ul>
  4. 9. University of Arizona--Results <ul><li>Plant-soil system effective in removing N and P from wastewater over a range of salinities </li></ul><ul><ul><li>Plants more effective at removing N </li></ul></ul><ul><ul><li>Some P leaching </li></ul></ul><ul><li>Significant differences among plant species in filtering capacity </li></ul><ul><li>Large land area required to treat a given area of aquaculture production, but cost is much lower relative to aquatic biofilters </li></ul>
  5. 10. NOAA Fisheries Restoration Center <ul><li>Coastal Habitat Restoration Activities </li></ul><ul><li>Natural Resource Damage Assessment Program (NRDA) </li></ul><ul><li>Restoration conducted pursuant to: </li></ul><ul><ul><li>Releases of hazardous materials (CERCLA) </li></ul></ul><ul><ul><li>Oil Spills (OPA) </li></ul></ul><ul><li>Community-Based Restoration </li></ul><ul><ul><li>Small Scale Restoration projects </li></ul></ul><ul><ul><li>Partnerships </li></ul></ul><ul><ul><li>Strong involvement from the local community </li></ul></ul><ul><li>Coastal Wetland Planning, Protection and Restoration Act </li></ul><ul><ul><li>Large-scale coastal wetland restoration in Louisiana </li></ul></ul>
  6. 11. US Fish & Wildlife Service <ul><li>USFWS—work with states to restore coastal and anadromous fisheries </li></ul><ul><li>Delaware River </li></ul><ul><li>Central New England </li></ul>
  7. 12. <ul><li>Restoring Coastal and Anadromous Fishes and Their Habitat on the US Atlantic Coast: Challenges and Opportunities </li></ul>Jed Brown Fisheries and Wildlife Division District Department of the Environment Washington, DC
  8. 13. Outline <ul><li>Biography/Background </li></ul><ul><li>Coastal/anadromous fish </li></ul><ul><ul><li>Species </li></ul></ul><ul><ul><li>Status and problems </li></ul></ul><ul><li>Navigation—vessel strike mortality in Atlantic sturgeon </li></ul><ul><li>Coastal fish habitat degradation from invasive species </li></ul><ul><ul><li>Salt marsh plants—common reed phragmites </li></ul></ul><ul><li>Dams—fish passage and trade-offs with hydropower </li></ul>
  9. 14. USFWS: Focus on estuarine , coastal and anadromous fish restoration Anadromous fish-- species that migrate into the ocean, mature, and return to rivers to spawn River herring Atlantic sturgeon American shad Sea lamprey Striped bass Atlantic salmon
  10. 16. Importance of anadromous fish <ul><li>Link between marine and freshwater systems (e.g. nutrient transfer) </li></ul><ul><li>Important commercial and recreational species </li></ul><ul><li>Prey source for marine/estuarine/freshwater fishes </li></ul><ul><li>Historical/cultural resource </li></ul>
  11. 17. Work to restore depleted populations <ul><li>Atlantic salmon—ESA listed </li></ul><ul><li>Shortnose sturgeon—ESA listed </li></ul><ul><li>Atlantic sturgeon—ESA candidate </li></ul><ul><li>American shad—Most populations declining </li></ul><ul><li>Alewife—Species of Concern </li></ul><ul><li>Blueback herring—Species of Concern </li></ul>
  12. 18. (Secor and Waldman, AFS Symposium 23:203-216,1999) Atlantic sturgeon landings, Delaware Bay
  13. 19. Delaware River and Estuary American shad harvest Sutton et al., 1996
  14. 21. <ul><li>1908 U.S. Shad landings ranked 2nd in volume behind Atlantic cod, and 3rd in value behind Pacific salmon and cod. </li></ul><ul><li>1960 U.S. shad landings fell to 34th in value and 48th in volume. </li></ul><ul><li>They are insignificant today </li></ul>Drying shad nets New Castle, DE c. 1900
  15. 22. Problems Habitat alteration Dams Pollution Over-harvest Invasive species Bycatch
  16. 23. Restoration & Research <ul><li>Fishery management </li></ul><ul><li>Habitat improvements </li></ul><ul><li>Hatchery production </li></ul><ul><li>Conduct research </li></ul><ul><ul><li>Causes of population declines </li></ul></ul><ul><ul><li>Emerging threats </li></ul></ul>
  17. 24. Outline <ul><li>Coastal/anadromous fish </li></ul><ul><ul><li>Species </li></ul></ul><ul><ul><li>Status and problems </li></ul></ul><ul><li>Navigation—vessel strike mortality in Atlantic sturgeon </li></ul><ul><li>Disease—striped bass mycobacteriosis </li></ul><ul><li>Coastal fish habitat degradation from invasive species </li></ul><ul><ul><li>Common reed phragmites (wetland plant) </li></ul></ul><ul><li>Dams—fish passage and trade-offs with hydropower </li></ul>
  18. 25. Atlantic Sturgeon Vessel-Strike Mortalities in the Delaware Estuary: Obstacle to recovery?
  19. 26. Atlantic Sturgeon <ul><li>3.5 meters </li></ul><ul><li>350 kilos </li></ul><ul><li>50-75 years old </li></ul><ul><li>Live in the ocean, return to rivers to spawn </li></ul><ul><li>Threatened due to overfishing, bycatch, habitat loss </li></ul><ul><li>40-year coast-wide harvest moratorium imposed in 1998 </li></ul><ul><li>Under consideration for listing as a federal Endangered Species </li></ul>
  20. 27. Delaware Estuary Tidal portion of the Delaware River Stretches from Trenton, NJ to the Mouth of the Delaware Bay Highly industrialized Historically supported largest Atlantic sturgeon population Delaware River, largest un-dammed river east of the Mississippi
  21. 28. <ul><li>Delaware Bay--largest Atlantic sturgeon fishery </li></ul><ul><li>Comprised 75% of U.S. harvests 1890-1899 </li></ul><ul><li>About 1000 fishermen engaged in this fishery in 1897 </li></ul><ul><li>The Delaware Bay may have supported an order of magnitude greater Atlantic sturgeon population than the other Atlantic coast estuaries </li></ul>Bayside (Caviar), NJ The caviar gold rush
  22. 30. Vessel-Strike Mortality <ul><li>Mortality caused by entrainment through the propellers of vessels and/or direct collisions with vessel hulls </li></ul>
  23. 31. Why are we concerned about ship strikes? <ul><li>Very low population sizes </li></ul><ul><ul><li>Largest population in Hudson River ~900 spawning adults </li></ul></ul><ul><ul><li>Altamaha River~350 spawning adults </li></ul></ul><ul><ul><li>Delaware unknown </li></ul></ul><ul><li>Long-lived fish </li></ul><ul><li>Slow to reach maturity </li></ul><ul><li>Highly vulnerable to impacts from human activities </li></ul>
  24. 32. Delaware River Port Complex <ul><li>Largest freshwater port </li></ul><ul><li>complex in the world </li></ul><ul><li>~3000 ships transit every year </li></ul><ul><li>Ports distant from Bay mouth </li></ul><ul><li>Ships transit 165 km from </li></ul><ul><li>ocean to reach Philadelphia </li></ul>
  25. 33. Philadelphia/Delaware River Ports <ul><li>DE </li></ul><ul><ul><li>Delaware City </li></ul></ul><ul><ul><li>Claymont </li></ul></ul><ul><ul><li>Reedy Point </li></ul></ul><ul><ul><li>Wilmington </li></ul></ul><ul><li>NJ </li></ul><ul><ul><li>Burlington </li></ul></ul><ul><ul><li>Camden </li></ul></ul><ul><ul><li>Delair </li></ul></ul><ul><ul><li>Gloucester </li></ul></ul><ul><ul><li>Paulsboro </li></ul></ul><ul><ul><li>Salem </li></ul></ul><ul><ul><li>Westville </li></ul></ul><ul><li>PA </li></ul><ul><ul><li>Chester </li></ul></ul><ul><ul><li>Eddystone </li></ul></ul><ul><ul><li>Fairless Hills </li></ul></ul><ul><ul><li>Marcus Hook </li></ul></ul><ul><ul><li>Philadelphia </li></ul></ul><ul><ul><li>Tullytown </li></ul></ul>
  26. 35. Total Vessel Calls 2007 Ocean-going vessels greater than 10,000 deadweight (DWT) Houston 6,195 LA/LB 5,492 New York 4,968 New Orleans 4,884 San Francisco 3,945 Philadelphia 3,148 Virginia Ports 2,775 Savannah 2,615 Col. River 2,578 Charleston 2,160 Top 10 38,760 All Ports 63,804
  27. 36. Delaware River Ship Channel <ul><li>Shipping channel </li></ul><ul><ul><li>203 km from the mouth of Delaware Bay to Bordentown, NJ (~24 km upstream of of Philadelphia) </li></ul></ul><ul><ul><li>Maintained at a depth of 12.2 m </li></ul></ul><ul><ul><li>Width varies from 122 m to 305m--channel is wider in the lower estuary and narrower upstream. </li></ul></ul>
  28. 37. Monitoring <ul><li>Delaware Division of Fish and Wildlife (DEDFW) began tracking sturgeon mortalities in 2005. </li></ul><ul><li>Carcasses were reported by citizens or directly by agency biologists </li></ul><ul><li>No dedicated survey program by DEDFW </li></ul><ul><li>All sturgeon were measured for total length (or length of portion found), scanned for tags, sexed when practical, examined for injuries, photo documented </li></ul>
  29. 38. Vessel strike mortalities 2005-2008 28 Atlantic sturgeon carcasses between 2005 and 2008 Ranged from Chester, PA to Cape Henlopen, DE 61% of the sturgeon were of adult size (exceeding or likely to exceed 150 cm total length if not severed) 75% of mortalities reported during the months of May and June Sturgeon had injuries consistent with being struck by a vessel
  30. 39. Probably only some fraction of the total vessel-strike mortalities that have occurred are reported <ul><li>Very few beaches or access areas along the length of the Delaware Bay </li></ul><ul><li>Much of the shoreline has dense marsh limiting public access and reducing the likelihood that a carcass will be found </li></ul><ul><li>Additionally the data are derived primarily from reports received by DEDFW, and not from any agencies on the New Jersey side of the Estuary. </li></ul>
  31. 40. Egg per Recruit Model <ul><li>VS 50% ~2.5% of the female population killed annually </li></ul><ul><li>If the total population is 1,000 females, then probably not more than 25 </li></ul><ul><li>females could be killed annually without negatively impacting the population </li></ul>Vessel-strike mortality rates that reduced maximum egg production by more than 50% ( VS 50%) were considered to be unsustainable
  32. 41. Avoiding Adverse Impacts <ul><li>2006, 9 mortalities in the Delaware Estuary </li></ul><ul><li>If this = 100% of mortalities in the Estuary (and were all female), then the population would need to exceed 360 female fish to avoid adverse population impacts </li></ul><ul><li>If this = 50% of the total sturgeon vessel-strike mortalities (and were all females), then the sturgeon population would need to be larger than 720 female fish, to avoid adverse impacts </li></ul>
  33. 42. Recommendations Detection/Research <ul><li>Detection </li></ul><ul><li>Directed ground or aerial surveys </li></ul><ul><li>Outreach to request public’s assistance in reporting carcasses </li></ul><ul><li>Creation of a centralized database for the Atlantic Coast </li></ul><ul><li>Trawl behind vessels to detect carcasses </li></ul>
  34. 43. Recommendations Prevention/Mitigation <ul><li>Reduced speed for ships during spawning season </li></ul><ul><ul><li>Proven effective for marine mammals </li></ul></ul><ul><ul><li>Reduces the force of collision impacts </li></ul></ul><ul><ul><li>Allows animals more time to detect and avoid oncoming vessels </li></ul></ul>
  35. 44. Recommendations Prevention/Mitigation Diverting sturgeon from channel <ul><li>Sound </li></ul><ul><ul><li>Ultrasound found effective in controlling the behavior of clupeids—no indication that sturgeon would be capable of detecting ultrasound </li></ul></ul><ul><li>Light </li></ul><ul><ul><li>Light such as mercury and strobe lights can be used to attract some species and divert others </li></ul></ul><ul><li>Scent </li></ul><ul><ul><li>Attracts sturgeon for feeding and reproduction </li></ul></ul>
  36. 45. Current research <ul><li>Delaware Fish & Wildlife continues to monitor mortalities </li></ul><ul><li>Delaware Fish & Wildlife and Delaware State University are conducting gillnetting and telemetry studies using acoustic transmitters (including depth sensing tags) </li></ul><ul><ul><li>Identify spawning grounds </li></ul></ul><ul><ul><li>Identify depths sturgeon utilize </li></ul></ul>
  37. 46. Delaware Deepening Project <ul><li>Army Corps of Engineers plans to </li></ul><ul><li>deepen main channel </li></ul><ul><li>by 5 feet from Bay mouth to Philadelphia </li></ul><ul><li>165 km </li></ul><ul><li>Larger vessels will transit the estuary </li></ul><ul><li>Increase in container and cargo vessels </li></ul>
  38. 47. Outline <ul><li>Biography/Background </li></ul><ul><li>Coastal/Anadromous fish </li></ul><ul><ul><li>Species </li></ul></ul><ul><ul><li>Status and problems </li></ul></ul><ul><li>Navigation—vessel strike mortality in Atlantic sturgeon </li></ul><ul><li>Coastal fish habitat degradation from invasive species </li></ul><ul><ul><li>Common reed phragmites (wetland plant) </li></ul></ul><ul><li>Dams—fish passage and trade-offs with hydropower </li></ul>
  39. 48. Growth characteristics and salt tolerance of a nonnative invasive population of the common reed Phragmites australis Coastal Habitat Degradation from Invasive Species
  40. 49. Phragmites australis (common reed) <ul><li>A tall (to over 4m), emergent wetland grass </li></ul><ul><li>World-wide distribution </li></ul><ul><li>Native to U.S. </li></ul><ul><li>A population from Eurasia has invaded US estuaries dominated by Spartina alterniflora </li></ul><ul><li>Haplotype—haploid genotype </li></ul>
  41. 50. The Problem <ul><li>Wide-spread expansion of nonnative Phragmites australis in coastal marshes in New England and mid-Atlantic states </li></ul><ul><li>(Not as widespread in the Southeast) </li></ul><ul><li>Displacing coastal Spartina alterniflora marshes </li></ul><ul><li>Once established, difficult to eradicate </li></ul>
  42. 51. Spartina alterniflora (smooth cordgrass)
  43. 52. The problem <ul><li>Phragmites marshes less valuable habitat than spartina marshes </li></ul><ul><ul><li>Less habitat for fishes </li></ul></ul><ul><ul><ul><li>Spartina marshes important habitat for Fundulus heteroclitus (mummichog) </li></ul></ul></ul><ul><ul><ul><li>Mummichog is a key prey species for estuarine fishes </li></ul></ul></ul><ul><ul><li>Reduced habitat value </li></ul></ul><ul><ul><li>for birds </li></ul></ul><ul><ul><li>Reduced plant diversity </li></ul></ul>
  44. 53. How does phragmites invade? (Able et al. 2003)
  45. 54. M - Haplotype F - Haplotype Photo: Bob Meadows, 2005 M-Haplotype (Invasive) F-Haplotype (Native)
  46. 55. Research questions <ul><li>Why is the invasive M population different? </li></ul><ul><li>Why has it become invasive and the native populations have not? </li></ul><ul><li>Can this information be used in managing phragmites? </li></ul>
  47. 56. Research objectives <ul><li>Compare the salinity tolerance and growth characteristics of the introduced haplotype of phragmites with: </li></ul><ul><ul><li>Two native haplotypes </li></ul></ul><ul><ul><li>Spartina alterniflora </li></ul></ul>
  48. 57. Source of plant material <ul><li>Rhizome sections of </li></ul><ul><li>P. australis were </li></ul><ul><li>collected from populations in </li></ul><ul><li>Delaware and Maryland </li></ul><ul><li>Samples included </li></ul><ul><li>two native </li></ul><ul><li>haplotypes (F & AC) </li></ul><ul><li>and the introduced </li></ul><ul><li>invasive </li></ul><ul><li>haplotype (M) </li></ul>AC F
  49. 58. Compare invasive phragmites to native phragmites and spartina under common garden conditions along a salinity gradient
  50. 60. Conclusions <ul><li>The invasive M haplotype of phragmites differs in ecophysiology from the native haplotypes </li></ul><ul><ul><li>Exhibits a greater rate of shoot initiation and biomass accumulation </li></ul></ul><ul><ul><li>Appears to be adapted to a weedy growth strategy </li></ul></ul><ul><ul><li>More salt tolerant than native populations </li></ul></ul><ul><ul><ul><li>Has allowed this population to invade salt mashes </li></ul></ul></ul><ul><li>M haplotype not as salt tolerant as spartina </li></ul><ul><ul><li>But can invade salt marshes with reduced salinity </li></ul></ul><ul><li>M haplotype performs well at intermediate salinities </li></ul><ul><ul><li>Special niche for the M haplotype </li></ul></ul>
  51. 61. Reasons for invasion on the Atlantic Coast <ul><li>Shoreline development </li></ul><ul><ul><li>Removal of upland woody vegetation </li></ul></ul><ul><ul><ul><li>No plants to remove freshwater via evapotranspiration </li></ul></ul></ul><ul><ul><ul><li>Greater freshwater input to marshes leads to lower salinity </li></ul></ul></ul><ul><ul><ul><li>Lowered salinity allows M haplotype to invade </li></ul></ul></ul><ul><li>Tidal restriction </li></ul><ul><ul><li>Dikes, levees, and poorly designed water-control structures </li></ul></ul><ul><ul><li>Poor flushing, fresh-water build-up </li></ul></ul><ul><ul><li>Allows M haplotype to colonize </li></ul></ul>
  52. 62. Restoration & Control Opportunities M Haplotype <ul><li>Before undertaking control, identify the origin of the population—don’t eradicate native populations! </li></ul><ul><li>Plant/ restore upland vegetation buffer </li></ul><ul><ul><li>Require developers to preserve an upland vegetation buffer (>10 m) </li></ul></ul><ul><li>Breach diked salt marshes </li></ul><ul><li>Conventional control (herbicides, burning, etc.) </li></ul><ul><li>Complete eradication of M haplotype highly unlikely </li></ul>
  53. 63. Outline <ul><li>Coastal/anadromous fish </li></ul><ul><ul><li>Species </li></ul></ul><ul><ul><li>Status and problems </li></ul></ul><ul><li>Navigation—Vessel strike mortality in Atlantic sturgeon </li></ul><ul><li>Disease—striped bass mycobacteriosis </li></ul><ul><li>Coastal fish habitat degradation from invasive species </li></ul><ul><ul><li>Common reed phragmites (wetland plant) </li></ul></ul><ul><li>Dams—fish passage and trade-offs with hydropower </li></ul>
  54. 64. Hydroelectric dams and fish passage <ul><li>Restoring anadromous fish around dams </li></ul>Essex Dam Lawrence, Mass Utility companies required to provide upstream and downstream fish passage at dams Construction of fishways renewed interested in fish restoration
  55. 65. Fish lifts and ladders
  56. 66. Goals in fish passage <ul><li>Primary Goal: reestablish runs to historic or sustainable numbers </li></ul><ul><li>Providing access to historical spawning habitat will result in increased population sizes </li></ul><ul><li>Technical goal: maximize passage, minimize delays, transit time, stress, and energetic and reproductive costs </li></ul>
  57. 67. Problems with conducting restoration on dammed rivers <ul><li>Fish lifts/ladders are inefficient </li></ul><ul><li>Fishways don’t pass many species, i.e. sturgeon, eel, rainbow smelt, striped bass </li></ul><ul><li>Increased energetic costs for shad </li></ul><ul><ul><li>Reduction in repeat spawning females </li></ul></ul><ul><ul><li>Decreases in the mean size and age of adult fish </li></ul></ul><ul><ul><li>Lower population fecundity and probably lower annual recruitment </li></ul></ul><ul><li>Predation at base of dams (striped bass) </li></ul><ul><li>Downstream mortality of outmigrating fish through turbines </li></ul>
  58. 68. Restoring anadromous fish on dammed rivers <ul><li>Does it work? </li></ul><ul><li>Look at Merrimack River and other dammed rivers </li></ul><ul><ul><li>Connecticut </li></ul></ul><ul><ul><li>Susquehanna </li></ul></ul>
  59. 69. Historic Fish Populations Merrimack River <ul><li>Atlantic salmon ~30,000 </li></ul><ul><li>American shad hundreds of thousands to millions </li></ul><ul><li>River herring millions to ten of millions </li></ul><ul><li>We attempt to restore fish populations to some percentage of these historical populations </li></ul>
  60. 70. Merrimack River <ul><li>177 km long </li></ul><ul><li>Drains 13000 sq. km </li></ul><ul><li>Multiple mainstem dams </li></ul><ul><li>with fish passage facilities </li></ul>
  61. 71. Connecticut River <ul><li>Largest river in New </li></ul><ul><li>England </li></ul><ul><li>645 km long </li></ul><ul><li>Drains 28,000 sq. km </li></ul><ul><li>Multiple mainstem </li></ul><ul><li>hydropower dams with </li></ul><ul><li>fish passage facilities </li></ul>
  62. 72. <ul><li>Susquehanna River </li></ul><ul><li>715 km long </li></ul><ul><li>Drains 71,000 sq. km </li></ul><ul><li>Largest tributary to Chesapeake Bay </li></ul><ul><li>Largest U.S. river that drains into the Atlantic Ocean </li></ul><ul><li>Multiple mainstem hydropower dams with fish passage facilities </li></ul>
  63. 73. American shad passage at Merrimack River dams 17% of the shad that pass the first dam pass the second dam
  64. 74. American shad passage at Connecticut River dams 4% of the shad that pass the first dam pass the second dam
  65. 75. American shad passage at Susquehanna River dams 34% of the shad that pass the first dam pass the second dam
  66. 76. American shad returns
  67. 77. So, does it work? <ul><li>Has worked in bringing some fish back to their historical spawning habitat where they were excluded by dams </li></ul><ul><li>No good evidence of successfully restoring fish populations to “ecologically significant” levels on Atlantic coastal rivers with multiple main stem dams </li></ul>
  68. 78. What is the trade-off for restoring around dams? <ul><li>Dams </li></ul><ul><ul><li>Produce electricity </li></ul></ul><ul><ul><li>Provide for recreation </li></ul></ul><ul><ul><li>Source for drinking water </li></ul></ul>
  69. 79. Value (benefit) <ul><li>First seven dams on Merrimack 80 MW maximum capacity </li></ul><ul><li>Provides about 0.2% of New England’s electricity (6 state region) </li></ul><ul><li>Powers about 0.5% of New England’s homes </li></ul><ul><li>Total Value= $20,519,381 </li></ul>
  70. 80. Costs of current arrangement <ul><li>USFWS and state restoration programs </li></ul><ul><ul><li>~$1 million/year </li></ul></ul><ul><li>Lost fish production </li></ul><ul><ul><li>?? </li></ul></ul>
  71. 81. Consider dam removal? <ul><li>Potential for fish populations to rebound to near historical numbers? </li></ul>
  72. 82. Costs of dam removal <ul><li>Value of foregone hydropower production </li></ul><ul><li>Dam removal costs – small to very large Uncertain who pays for dam removal </li></ul><ul><li>Foregone aesthetic and recreational benefits (primarily associated with the impoundments) </li></ul>
  73. 83. Economics <ul><li>Decisions to remove dams usually not made on basis of cost-benefit analysis (e.g., Elwa River, WA) </li></ul>
  74. 84. Way forward <ul><li>Continue current restoration efforts </li></ul><ul><ul><li>Allows fish access to historic spawning grounds </li></ul></ul><ul><ul><li>Generate economic benefit of hydropower production </li></ul></ul><ul><ul><li>Continue to work with dam owners to modify/improve fishway operations </li></ul></ul><ul><ul><li>Probably won’t see fish populations return to historical levels </li></ul></ul><ul><ul><li>May impact rebuilding populations of marine fish that feed on shad and river herring </li></ul></ul>
  75. 85. Way forward <ul><li>Consider planting the seed of dam removal? </li></ul><ul><ul><li>Penobscot River, Maine as a model </li></ul></ul><ul><ul><li>A trust purchased three dams from the dam owners </li></ul></ul><ul><ul><li>Remove the two lower-most dams on the river </li></ul></ul><ul><ul><li>Construct a state-of-the-art fish bypass around the third dam </li></ul></ul><ul><ul><li>Give power company the opportunity to increase generation at six existing dams, which would result in more than 90% of the current energy generation being maintained </li></ul></ul>
  76. 86. Conclusions <ul><li>Atlantic sturgeon face a difficult road to recovery </li></ul><ul><li>Invasive species will continue to present a challenge to fish and coastal habitat restoration programs and will be difficult to eradicate </li></ul><ul><li>Shift focus from fishways to dam removals to restore anadromous fish populations </li></ul>
  77. 87. Thailand <ul><li>Sustainable aquaculture </li></ul><ul><ul><li>Restoration of abandoned ponds </li></ul></ul><ul><ul><li>Best Management Practices </li></ul></ul><ul><li>Coastal restoration/planning </li></ul><ul><li>Estuarine ecology </li></ul><ul><li>Wetland/mangrove ecology </li></ul><ul><li>Fisheries management/policy </li></ul><ul><li>Marine conservation </li></ul><ul><li>Invasive species </li></ul>
  78. 88. Collaborators <ul><li>Atlantic sturgeon </li></ul><ul><ul><li>Greg Murphy, Delaware Division of Fish & Wildlife </li></ul></ul><ul><li>Phragmites </li></ul><ul><ul><li>Ed Vasquez, Ed Glenn, Steve Nelson, University of Arizona </li></ul></ul><ul><ul><li>Glenn Guntenspergen, US Geological Survey </li></ul></ul>
  79. 89. Thank you!
  80. 90. Egg Per Recruit Model n = oldest spawning age, λ = the proportion of females that are mature at age i, φi = mean fecundity of a female at age I VS = instantaneous rate of vessel-strike mortality during the period t M = instantaneous natural mortality rate Assumptions Maximum age of 60 years Constant M of 0.07 over all ages Fishing and bycatch mortality rates equal to zero Sturgeon are vulnerable to vessel-strikes starting at age 3 Vessel-strike mortality rates that reduced maximum egg production by more than 50% were unsustainable