Shark fishery assessment
Paul Tuda
2024-05-31
Setup
set default chunk options
Load the data
## Date family_name species_name common_name folk_length
## 1 20.04.2020 Carcharhinidae Prionace glauca Blue shark 219
## 2 20.04.2020 Carcharhinidae Prionace glauca Blue shark 244
## 3 23.04.2020 Carcharhinidae Prionace glauca Blue shark 240
## 4 29.04.2020 Carcharhinidae Prionace glauca Blue shark 250
## 5 29.04.2020 Carcharhinidae Prionace glauca Blue shark 202
## 6 29.04.2020 Carcharhinidae Prionace glauca Blue shark 239
## total_length
## 1 NA
## 2 NA
## 3 NA
## 4 267
## 5 213
## 6 256## 'data.frame': 945 obs. of 6 variables:
## $ Date : chr "20.04.2020" "20.04.2020" "23.04.2020" "29.04.2020" ...
## $ family_name : chr "Carcharhinidae" "Carcharhinidae" "Carcharhinidae" "Carcharhinidae" ...
## $ species_name: chr "Prionace glauca" "Prionace glauca" "Prionace glauca" "Prionace glauca" ...
## $ common_name : chr "Blue shark" "Blue shark" "Blue shark" "Blue shark" ...
## $ folk_length : num 219 244 240 250 202 239 251 293 237 250 ...
## $ total_length: num NA NA NA 267 213 256 272 319 253 267 ...data formating
## Date family_name species_name common_name folk_length
## 1 2020-04-20 Carcharhinidae Prionace glauca Blue shark 219
## 2 2020-04-20 Carcharhinidae Prionace glauca Blue shark 244
## 3 2020-04-23 Carcharhinidae Prionace glauca Blue shark 240
## 4 2020-04-29 Carcharhinidae Prionace glauca Blue shark 250
## 5 2020-04-29 Carcharhinidae Prionace glauca Blue shark 202
## 6 2020-04-29 Carcharhinidae Prionace glauca Blue shark 239
## total_length
## 1 NA
## 2 NA
## 3 NA
## 4 267
## 5 213
## 6 256Basic statistics
## Date family_name species_name common_name
## Min. :2016-01-11 Length:945 Length:945 Length:945
## 1st Qu.:2018-08-30 Class :character Class :character Class :character
## Median :2020-05-04 Mode :character Mode :character Mode :character
## Mean :2019-08-02
## 3rd Qu.:2020-07-01
## Max. :2020-08-16
##
## folk_length total_length
## Min. : 54.0 Min. : 61.0
## 1st Qu.:145.0 1st Qu.:198.0
## Median :186.0 Median :250.0
## Mean :187.2 Mean :234.4
## 3rd Qu.:234.0 3rd Qu.:283.0
## Max. :330.0 Max. :346.0
## NA's :83 NA's :484Model fitting
##
## Call:
## lm(formula = total_length ~ folk_length, data = data)
##
## Residuals:
## Min 1Q Median 3Q Max
## -217.28 -25.48 -1.57 29.54 157.09
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 66.2699 9.0282 7.34 1.27e-12 ***
## folk_length 0.8154 0.0430 18.96 < 2e-16 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 48.95 on 386 degrees of freedom
## (557 observations deleted due to missingness)
## Multiple R-squared: 0.4823, Adjusted R-squared: 0.4809
## F-statistic: 359.6 on 1 and 386 DF, p-value: < 2.2e-16
Estimate missing values
## Date family_name species_name common_name folk_length
## 1 2020-04-20 Carcharhinidae Prionace glauca Blue shark 219
## 2 2020-04-20 Carcharhinidae Prionace glauca Blue shark 244
## 3 2020-04-23 Carcharhinidae Prionace glauca Blue shark 240
## 4 2020-04-29 Carcharhinidae Prionace glauca Blue shark 250
## 5 2020-04-29 Carcharhinidae Prionace glauca Blue shark 202
## 6 2020-04-29 Carcharhinidae Prionace glauca Blue shark 239
## total_length
## 1 238.2928
## 2 265.4853
## 3 261.1345
## 4 267.0000
## 5 213.0000
## 6 256.0000size structure analysis
## # A tibble: 5 × 9
## species_name mean_total_length median_total_length min_total_length
## <chr> <dbl> <dbl> <dbl>
## 1 Carcharhinus falciform… 145. 136. 70.8
## 2 Carcharhinus longimanus 162. 163. 80.6
## 3 Isurus oxyrinchus 224. 222. 109
## 4 Prionace glauca 257. 264. 58.8
## 5 carcharhinus falciform… 272. 272. 272.
## # ℹ 5 more variables: max_total_length <dbl>, mean_folk_length <dbl>,
## # median_folk_length <dbl>, min_folk_length <dbl>, max_folk_length <dbl>data visualization
density plots
Box plots
Total length box plots
Temporal anaylsis
## Date family_name species_name common_name folk_length
## 1 2020-04-20 Carcharhinidae Prionace glauca Blue shark 219
## 2 2020-04-20 Carcharhinidae Prionace glauca Blue shark 244
## 3 2020-04-23 Carcharhinidae Prionace glauca Blue shark 240
## 4 2020-04-29 Carcharhinidae Prionace glauca Blue shark 250
## 5 2020-04-29 Carcharhinidae Prionace glauca Blue shark 202
## 6 2020-04-29 Carcharhinidae Prionace glauca Blue shark 239
## total_length year_month
## 1 238.2928 2020-04-01
## 2 265.4853 2020-04-01
## 3 261.1345 2020-04-01
## 4 267.0000 2020-04-01
## 5 213.0000 2020-04-01
## 6 256.0000 2020-04-01## Date family_name species_name common_name folk_length
## 1 2020-04-20 Carcharhinidae Prionace glauca Blue shark 219
## 2 2020-04-20 Carcharhinidae Prionace glauca Blue shark 244
## 3 2020-04-23 Carcharhinidae Prionace glauca Blue shark 240
## 4 2020-04-29 Carcharhinidae Prionace glauca Blue shark 250
## 5 2020-04-29 Carcharhinidae Prionace glauca Blue shark 202
## 6 2020-04-29 Carcharhinidae Prionace glauca Blue shark 239
## total_length year_month month_name
## 1 238.2928 2020-04-01 April
## 2 265.4853 2020-04-01 April
## 3 261.1345 2020-04-01 April
## 4 267.0000 2020-04-01 April
## 5 213.0000 2020-04-01 April
## 6 256.0000 2020-04-01 AprilSummarize the number of individuals caught by month and species
## # A tibble: 36 × 3
## # Groups: month_name [11]
## month_name species_name individuals_caught
## <ord> <chr> <int>
## 1 January Carcharhinus longimanus 4
## 2 January Prionace glauca 1
## 3 February Prionace glauca 3
## 4 March Prionace glauca 5
## 5 April Carcharhinus falciformis 2
## 6 April Carcharhinus longimanus 24
## 7 April Isurus oxyrinchus 11
## 8 April Prionace glauca 34
## 9 May Carcharhinus falciformis 33
## 10 May Carcharhinus longimanus 18
## # ℹ 26 more rowsPlot the number of individuals caught by month and species
Plot the size distribution (Total Length) by month and species
