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Regional ImpactAssessmentofDerelictFishingGearintheChesapeakeBay
AmyV.UhrinChiefScientist
NOAAMarineDebrisProgram
Briefingfor:ChesapeakeBayProgram
SustainableFisheriesGITExecutiveCommittee
May23,2016
marinedebris.noaa.gov
Goal
Developacomprehensive,regionalimpactassessmentaimedatestimatingthecumulativeimpactsofderelictcrabpotsonnaturalresourcesinChesapeakeBay
1) Identify/evaluatefactorscontributingtodistributionanddensitiesofderelictbluecrabtraps
2) InventoryavailabledatawithregardtoObj.1
3) Identifyandfilldatagaps
4) DevelopaspatialmodeltoevaluateObj.1factors
5) Quantifyecological/economicimpactsofDFG
6) DevelopaDFGframeworkforuseinotherfisheries
Objectives
GeographicWeightedRegression
Responsevariable=derelictfishinggeardensity*
Predictorvariables=fishingeffort†,depth**,vessels††,location***
*MD:systematic,sidescansonarsurveys(2007);watermencleanups(2010,2012)VA:fishermenfieldsurveys/removals(2008‐2012);tributary‐specificsurveys(2005‐2011,2015)
†MD:activetrapsfieldsurveys(2007‐2012);MDDNRreports(1994‐2014);interviews(2014‐2016)VA:activetrapsfieldsurvey(2010);VMRCreports(1994‐2014)
**1995NOAAHydrographicSurveydata
††expertknowledge,AutomaticIdentificationSystemdata
***NOAAfishinglocationcodes
Objective4– spatialmodel
Objective4– spatialmodel
Baltimore
PredictionGridFieldData
Objective4– spatialmodelPredictionGrid PredictedHotspots
Derelict Crab Pot Density (km2)High : 185.767
Low : 0.587677
Objective4– spatialmodel
Tributary‐specificwork(10)
Objective5– ecologicalimpacts
Mortality• Bluecrab
Bycatchmortality• Terrapin• Whiteperch• Croaker• Blackseabass• Spot• Reddrum
Habitat• SAV,oysterbeds
Objective5– economicimpacts
• Estimatesannualharvestsasafunctionofeffort(numberofpots),stock,andderelictgearremovals
• Predictsharvestswithandwithoutderelictgearremovals
• Comparesmodelpredictionstoevaluateeffectofremovalsoncommercialharvests
Spatially‐explicitharvestmodel*
*Scheld etal.2016.Thedilemmaofderelictgear.ScientificReports6:19671
Objective5– economicimpacts
#TrapsRemoved
Avg Poundsof
IncreasedHarvest
Avg IncreasedRevenue
Virginia* 34,397 30million(27%)
$21.2million
Maryland 9,560 8million(16%)
$10.9million
*Scheld etal.2016.Thedilemmaofderelictgear.ScientificReports6:19671
Spatially‐explicitharvestmodel
Bay‐wide
Objective5– economicimpacts
Spatially‐explicitharvestmodel
Objective5– economicimpacts
Spatially‐explicitharvestmodel
Objective6– guidingframeworkDFGManagement
Fishery Impacts of DFGs
Cost of lost gear
Habitat & Resource Impacts
Model DFG Reduction Impact
Scenarios
MD Chesapeake Estimates
VA Chesapeake Estimates
Chesapeake Bay‐wide Estimates
Identify Core DFG Metrics
& Data Gaps
Recommend Assessment
Methods / Metrics
Chesapeake Bay Case Study
EcologicalImpacts
Economic Impacts
Crab Pot Density Distributions
Blue Crab CPUE Distributions
Spawning Female Density
Identify Spatial Patterns
VMRC | MD DNRBAY‐WIDE
VIMS economic model
DFG Removal Distributions
Blue Crab Impacts
Identify, map & rank
Identify, map & rank
White Perch Impacts
Identify, map & rank
Turtle Nesting Impacts
Identify, map & rank
Benthic Spp. Impacts
Mapping&ModelingBathymetry, Depth, Seagrass, Sediments
Blue Crab VMRC | MD DNR
White PerchVMRC | MD DNR
Terrapin Turtles Distributions / nesting
beaches (VMRC)
Fishing EffortVMRC | MD DNRFishery Effort
VMRC | MD DNR
Within Bay Regional Variance Matrix
Weighted Spatial Data
Matrix
DFGVMRC | MD DNR
Fishery Resource Population estimates(Landings & Bycatch)VMRC | MD DNR
Salinity, H2O QualitySpring‐Winter Flows
EnvironmentalCovariates
Benthic SpeciesSpot, Croaker, Drum Oyster, Mussels
VMRC | MD DNR