SEDAR91USCaribbeanSpinyLobster Indexwork
Stephanie Martínez Rivera, PhD
Fish Biologist
Southeast Fisheries Science Center
Caribbean Fisheries Branch
Kevin McCarthy Branch Chief
Southeast Fisheries Science Center
Caribbean Fisheries Branch
SEDAR 91 Puerto Rico Spiny Lobster: Landings
SEDAR 91 Puerto Rico Spiny Lobster: Trips
SEDAR 91 Puerto Rico Spiny Lobster: Nominal CPUE
Daniel Matos-Caraballo, Jesús León-Fernández, Luis A. Rivera-Padilla, and Wilson Santiago-Soler
SEDAR91-DW-03
Puerto Rico Spiny Lobster: Trap Nominal CPUE
Puerto Rico Spiny Lobster: Trap Trips
Puerto Rico Spiny Lobster: Dive CPUE
Puerto Rico Spiny Lobster: Dive Trips
Number of Puerto Rico Reported Commercial Dive Trips with Lobster Landings by Coast
Number of commercial fishing trips with lobster landings
0 5,000 10,000 15,000 20,000 25,000
Diving EAST
Diving WEST
Diving NORTH
DIVING ALL Total
Diving SOUTH
Puerto Rico Spiny Lobster: Standardized Index of Abundance
Fishery-dependentindicesofabundance:availabledata
✓ Landingsandfishingeffortofcommercialfishersfromthe CaribbeanCommercialLogbook(CCL)
✓ Eachfishingtriphasauniquetripidentifier,thelandingdate, fishinggear,coast,gear-specificfishingeffort,speciescaught, andweightofthelandings
✓ Datasubsetting
✓ Catchperuniteffort(CPUE)definedaswholeweightpergear quantity(trapsfished,SCUBAtanksused)
Methods
● Dataexploration
● Groupsimilargears
● Outlierremoval
● Dataexclusions
● Yearsincluded
● Timeperiodbasedonsamplesize
● Datawererestrictedtoincludeonlytripsthathadgear effortinformation
● CalculatedstandardizedCPUE
Fish Trap Index: sample size and time period
Lobster Trap Index: sample size and time period
Dive Index: sample size and time period
Data subsetting
Whichtripsfishedinlobsterhabitat?
● Speciesassociationtoidentifytrips
● StephensandMacCallmethod
● usesmultiplelogisticregressiontoestimatea probabilityforeachtripthatspinylobsterwas caught,givenotherspeciescaughtonthattrip
● Gear-Diveandfishtrap
● Coast–N,S,E,W
Stephens and MacCall results: Fish Traps
Stephens and MacCall results: Dive
Analyses
● CPUEwasmodeledusingthedelta-GLMapproach
○ Combinestwoseparategeneralizedlinearmodels
■ Onetodescribepresence/absence–Bernoullisubmodel
■ Onetodescribecatchratesofsuccessfultrips–Positive CPUEmodel
Analyses: Evaluation of explanatory variables
● YEAR–Yearsmodeledwere2001-2024(fishtrap)and2012-2024(dive)
● SEASON–December-April,dryseason;May-November,wetseason
● COAST
○ fishtrapindex:South,East,West
○ diveindex:North,South,East,West
● GEARQUANTITY–Quantilesofgearquantity(numberoftrapsfished, numberofSCUBAtanksused),binomialmodelonly
Analyses: Bernoulli submodel
• Initially,allexplanatoryvariableswereincludedinthemodelasmain effects
• ThenstepwiseAIC(VenablesandRipley1997)withabackwards selectionalgorithmwasusedtoeliminatethosevariablesthatdidnot improvemodelfit
• Finalmodels:
■ Fish trap index
● CPUE~YEAR+COAST+GEAR_QUANTITY
■ Dive index
● CPUE~YEAR+COAST+SEASON+GEAR_QUANTITY
Analyses: Positive CPUE submodel
• Twoparametricdistributionswereconsideredformodelingpositivevaluesof CPUE,lognormalandgamma–Lognormaloutperformedgamma
• Initially,allexplanatoryvariableswereincludedinthemodelasmaineffects
• ThenstepwiseAIC(VenablesandRipley1997)withabackwardsselection algorithmwasusedtoeliminatethosevariablesthatdidnotimprovemodelfit
• Finalmodels:
■ Fish trap index
● CPUE~YEAR+COAST
■ Dive index
● CPUE~YEAR+COAST
Fish Trap Index
Fish Trap Index: diagnostics
Bernoulli submodel: fits to binomial data
Lognormal submodel fits to positive CPUE data
Fish Trap Index: diagnostics
Top left - Histogram of empirical CPUE with the lognormal distribution overlaid
Bottom left - Quantile-quantile plot of residuals from the fitted lognormal submodel to the positive cpue catch
Dive Index
Dive Index: diagnostics
Bernoulli submodel: fits to binomial data
Dive Index: diagnostics
Lognormal submodel fits to positive CPUE data
Dive Index: diagnostics
Top left - Histogram of empirical CPUE with the lognormal distribution overlaid
Bottom left - Quantile-quantile plot of residuals from the fitted lognormal submodel to the positive cpue catch
Standardized Indices of Abundance
Thank you!
¡Gracias!
Data exploration
Data exploration
Data exploration
Data exploration
Relative nominal CPUE
SEDAR 91 US Caribbean Spiny Lobster
Commercial landings in pounds of Caribbean Spiny Lobster by year and gear group in Puerto Rico after outlier removal
SEDAR 91 US Caribbean Spiny Lobster
Number of trips with reported landings of Caribbean Spiny Lobster by year and gear group in Puerto Rico after outlier removal
SEDAR 91 US Caribbean Spiny Lobster
✓ Fishery-dependentindexwork
✓ Landingsandfishingeffortofcommercialfishers fromtheCaribbeanCommercialLogbook(CCL)
✓ Eachfishingtriphasauniquetripidentifier,the landingdate,fishinggear,coast,gear-specificfishing effort,speciescaught,andweight(lbs)ofthe landings
✓ StevensandMcCallanalysis
✓ Catchperuniteffort(CPUE)definedaswhole weightpergearquantity
Fish trap trips with gear quantity data
