The hardware and bandwidth for this mirror is donated by dogado GmbH, the Webhosting and Full Service-Cloud Provider. Check out our Wordpress Tutorial.
If you wish to report a bug, or if you are interested in having us mirror your free-software or open-source project, please feel free to contact us at mirror[@]dogado.de.
Analyze juvenile fish proportions in catches using length-weight relationships and catch data.
Calculate juvenile percentages from length frequency data:
# Calculate juvenile percentages
juvenile_results <- summarize_juveniles_by_group(
data = your_length_data,
group_cols = c("date", "fishing_zone"),
length_cols = c("8", "9", "10", "11", "12", "13"),
juvenile_limit = 12, # Size threshold in cm
a = 0.0012, # Length-weight coefficient
b = 3.1242 # Length-weight exponent
)
Use species-specific parameters for weight calculations:
# Calculate fish weights from lengths
weights <- calculate_fish_weight(
length = c(8, 10, 12, 14),
a = 0.0048, # Coefficient for anchoveta
b = 3.067 # Exponent for anchoveta
)
# Apply catch weighting to length frequencies
weighted_data <- apply_catch_weighting(
data = your_data,
length_cols = c("8", "9", "10", "11", "12"),
catch_col = "total_catch",
a = 0.0048,
b = 3.067
)
Calculate juvenile proportions:
# Single sample calculation
juv_percent <- calculate_juvenile_percentage(
frequency = c(10, 25, 40, 30, 15), # Frequencies by length
length = c(8, 9, 10, 11, 12), # Length classes
juvenile_limit = 10 # Juvenile threshold
)
# Get length ranges from frequency data
min_length <- get_length_range(
frequency = c(0, 5, 10, 20, 15, 0),
length = c(8, 9, 10, 11, 12, 13),
type = "min"
)
Convert length frequencies to weight estimates:
Create juvenile analysis plots:
# Plot juvenile analysis
juvenile_plot <- plot_juvenile_analysis(
data = your_data,
x_var = "date",
length_cols = c("8", "9", "10", "11", "12"),
plot_type = "bars",
title = "Juvenile Analysis Over Time"
)
# Create comprehensive dashboard
dashboard <- create_fishery_dashboard(
data = complete_data,
date_col = "date",
length_cols = find_columns_by_pattern(complete_data, "^[0-9]")
)
Common parameters for Peruvian species:
Species | a | b | Juvenile Limit (cm) |
---|---|---|---|
Anchoveta | 0.0048 | 3.067 | 12 |
Sardina | 0.0091 | 3.152 | 15 |
Jurel | 0.0079 | 3.089 | 20 |
For parameter recommendations and detailed examples, see the function documentation.
Froese, R. (2006). Cube law, condition factor and weight–length relationships: history, meta-analysis and recommendations. Journal of Applied Ichthyology, 22(4), 241-253. https://doi.org/10.1111/j.1439-0426.2006.00805.x
IMARPE (2020). Protocolo Elaboración de la Tabla de Decisión para la determinación del Límite Máximo Total Permisible por temporada de pesca en la pesquería del stock norte-centro de la anchoveta peruana. IMP-DGIRP/AFDPERP, Edición: 05, Revisión 00, 40p.
These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.