Evaluation of Neodymium-Iron-Boride Magnets as Selective Shark Repellents on Demersal Longlines

download Evaluation of Neodymium-Iron-Boride Magnets as Selective Shark Repellents on Demersal Longlines

of 38

  • date post

    12-Jan-2016
  • Category

    Documents

  • view

    25
  • download

    0

Embed Size (px)

description

Evaluation of Neodymium-Iron-Boride Magnets as Selective Shark Repellents on Demersal Longlines. Michael M. Herrmann, July 17, 2006. Introduction. What we know to date: Materials Geometries Tonic Immobility responses Effects on Fish Rigging Preliminary results on demersal lines. - PowerPoint PPT Presentation

Transcript of Evaluation of Neodymium-Iron-Boride Magnets as Selective Shark Repellents on Demersal Longlines

  • Evaluation of Neodymium-Iron-Boride Magnets as Selective Shark Repellents on Demersal LonglinesMichael M. Herrmann, July 17, 2006

  • IntroductionWhat we know to date:MaterialsGeometriesTonic Immobility responsesEffects on FishRiggingPreliminary results on demersal lines

  • MaterialsNIBNeodymium-iron-boride sinter with Ni or Zn plateNd2Fe4B (Empirical)Highest flux per size (BHmax is > 50 MGOe) N50Poor corrosion resistanceCeramicsBarium-ferrite materialBaFe12O19 (Empirical)Cheap and heavy, largest flux areaSmCoSamarium-cobalt sinterSmCo5, Sm2Co17(Empirical) Corrosion-resistance and expensive (BHmax ~43 MGOe)

  • MaterialsNIBNeodymium-iron-boride sinter with Ni or Zn plateNd2Fe4B (Empirical)Highest flux per size (BHmax is > 50 MGOe) N50Poor corrosion resistanceCeramicsBarium-ferrite materialBaFe12O19 (Empirical)Cheap and heavy, largest flux areaSmCoSamarium-cobalt sinterSmCo5, Sm2Co17(Empirical) Corrosion-resistance and expensive (BHmax ~43 MGOe)

  • MaterialsNIBNeodymium-iron-boride sinter with Ni or Zn plateNd2Fe4B (Empirical)Highest flux per size (BHmax is > 50 MGOe) N50Poor corrosion resistanceCeramicsBarium-ferrite materialBaFe12O19 (Empirical)Cheap and heavy, largest flux areaSmCoSamarium-cobalt sinterSmCo5, Sm2Co17 (Empirical) Corrosion-resistance and expensive (BHmax ~43 MGOe)

  • Tonic Immobility AssayFields greater than 50G will terminate TI at a distance of 0.0 0.3m

  • Responses to Magnets - SharksFree-swimming sharks will turn off of a buried magnet

  • Responses to Magnets - SharksDiminishing response with continuing exposureMagnetosense appears to be switchableHigh olfactory stimulation overrides magnetosense

    Magnet at d=0.0m to shark, no response

  • Responses to Magnets - SharksDiminishing response with continuing exposureMagnetosense appears to be switchableHigh olfactory stimulation overrides magnetosense

    Diminishing response

  • Responses to Magnets - SharksDiminishing response with continuing exposureMagnetosense appears to be switchableHigh olfactory stimulation overrides magnetosense

    Essentially no response

  • Responses to Magnets - SharksSpotted wobbegongs (O. maculatus) do not appear to respond to NIB and BaFerrite magnets

  • Responses to Magnets - TeleostsIATTC Achotines, Panama, July 2005Feeding preference trials in Thunnus albacares (magnetoreceptive)

    University of Miami, RSMAS, August 2005Feeding preference trials in Rachycentron canadum

    Feeding behavior is not affected by the presence of NIB magnets

  • Responses to Magnets - TeleostsIATTC Achotines, Panama, July 2005Feeding preference trials in Thunnus albacares (magnetoreceptive)

    University of Miami, RSMAS, August 2005Feeding preference trials in Rachycentron canadum

    Feeding behavior is not affected by the presence of NIB magnets

  • Selecting a GeometryOptimum geometry is pyramidal stacking

  • Selecting a GeometryOptimum geometry is pyramidal stackingHighest measurable flux at tips

  • Selecting a GeometryOptimum geometry is pyramidal stackingHighest measurable flux at tips9,000G - 9,300G

  • Practical Rigging1x1 cylinder with 3/16 center bore is preferredShape the magnetic flux to encompass the bait

  • Shaping the Flux1x1 cylinder with 3/16 center bore is preferredShape the magnetic flux to encompass the bait

    Steel tophat

  • Shaping the Flux

  • Rigging

  • Rigging2 Steel tophat1 NIBSleeve16/0 hook

  • Possible Galvanic CellSteel with cold galvanizing compoundCopper sleevePassive Ni-plate NIBMild steel tophat+ + + + + + +

  • RiggingNIB

  • Setting the Demersal Line1 demersal line with 15 16/0 circle hooksSame type of baitL-P Hook Event Timers24 hour rebait periodsLines checked every 4 hoursAlternating magnets and controls

  • Setting the Demersal Line

  • Setting the Demersal Line

  • Preliminary ResultsN48 square blocks, 67 hour total soak timeNOVEMBER 20052x2x1/8 square N48

  • Preliminary ResultsN48 square blocks, 67 hour total soak timeNOVEMBER 20051x1x1/8 square N48High flux, clumsy shape

  • Preliminary ResultsN48 square blocks, 67 hour total soak timeNo sharks captured on treatment hooksNOVEMBER 2005

    Chart1

    1

    0

    Sharks Captured

    Sheet1

    Controls1Nov-05N48 no tophat

    Treatments0

    Controls2Feb-06Minimags N48 no tophat

    Treatments1

    Controls1Feb-06N48 no tophat

    Treatments1

    Controls36-JunN50 with tophat, 14 hooks

    Treatments0

    Sheet1

    Sharks Captured

    Sheet2

    Sheet3

  • Preliminary ResultsN48 mini-cylinders, 24 hour total soak timeFEBRUARY 2006 UNDERSIZED MAGNETS0.4 x 1 minicylinders

  • Preliminary ResultsN48 mini-cylinders, 24 hour total soak timeFEBRUARY 2006 UNDERSIZED MAGNETS0.4 x 1 minicylindersPolarized along length, weak flux

  • Preliminary ResultsN48 mini-cylinders, 24 hour total soak timeFEBRUARY 2006 UNDERSIZED MAGNETS3 tigers (TL>2m) in same 4hr period

  • Preliminary ResultsN48 1 cylinders, 24 hour total soak timeFEBRUARY 2006 CONTINUED1x1 N48 cylinders

  • Preliminary ResultsN48 1 cylinders, 24 hour total soak timeFEBRUARY 2006 CONTINUEDSharpnose

    Chart6

    1

    1

    Sharks Captured

    Sheet1

    Controls1Nov-05N48 no tophat

    Treatments0

    Controls2Feb-06Minimags N48 no tophat

    Treatments1

    Controls1Feb-06N48 no tophat

    Treatments1

    Controls36-JunN50 with tophat, 14 hooks

    Treatments0

    Sheet1

    Sharks Captured

    Sheet2

    Sharks captured

    Sheet3

    Sharks Captured

    Sharks Captured

  • Preliminary ResultsN50 1x1 cylinder with 2 tophatN50 1 cylinders with tophats, 48 hour total soak timeJUNE 2006

  • Preliminary ResultsN50 1 cylinders with tophats, 48 hour total soak timeNo sharks captured on treatmentsJUNE 2006

    Chart4

    3

    0

    Sharks Captured

    Sheet1

    Controls1Nov-05N48 no tophat

    Treatments0

    Controls2Feb-06Minimags N48 no tophat

    Treatments1

    Controls1Feb-06N48 no tophat

    Treatments1

    Controls36-JunN50 with tophat, 14 hooks

    Treatments0

    Sheet1

    Sharks Captured

    Sheet2

    Sharks captured

    Sheet3

    Sharks Captured

    Sharks Captured

  • Next StepsMany more testsCPUE is too lowNovember 2006 NOAA cruiseAlaskan and Chilean fisheries

  • AcknowledgementsBimini Biological Field StationDr. Samuel GruberSteve Kessel, Tristan Guttridge, Grant Johnson, Katie Grudecki, Jo Imhoff, and the crewVernon Scholey, IATTCNOAA PascagoulaMark A. GraceCharles Bergmann RSMASDr. Dan BenettiPatrick H. RiceWWF SmartGear 2006 CommitteeKim DavisRodrigo DonadiGeorge Mizzell, ENG Concepts