aLBI: Estimating Length-Based Indicators for Fish Stock

Overview

aLBI is a specialized R package for fish stock assessment in data-limited scenarios. It implements a simplified framework for estimating life-history parameters and assessing stock status using length-frequency data, following the methods of Froese (2004) and Cope & Punt (2009).

Key Features in v0.1.9

• Enhanced Reliability: Direct user input for Linf and Lmat is now supported to improve model accuracy and allow for sensitivity analysis.
• Statistical Robustness: Integrated Monte Carlo simulations and non-parametric bootstrapping for reliable parameter estimation.
• New Functionality:
  • LWR: Fits and visualizes length-weight relationships.
  • FreqTM: Handles multi-month length-frequency data structures.
  • Updated FrequencyTable, FishPar, and FishSS with automated decision-making logic for selectivity.

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Installation

#installing pacakge from CRAN #install.packages("aLBI")

Key Features in v0.1.9

Enhanced Reliability: Direct user input for Linf and Lmat is now supported to improve model accuracy and allow for sensitivity analysis.

Statistical Robustness: Integrated Monte Carlo simulations and non-parametric bootstrapping for reliable parameter estimation.

New Functionality:

• LWR: Fits and visualizes length-weight relationships.

• FreqTM: Handles multi-month length-frequency data structures.

• Updated FrequencyTable, FishPar, and FishSS with automated decision-making logic for selectivity.

Installation

Install the stable version from CRAN:

#install.packages("aLBI")

For the latest development version with advanced sensitivity features, install from GitHub:

install.packages("devtools")

devtools::install_github("Ataher76/aLBI", force = TRUE) Quick Start R library(aLBI)

1. Estimate length parameters and sustainability indicators

Supports user-defined Linf and Lmat for sensitivity analysis

results <- FishPar(data = your_data, resample = 1000, Linf = NULL, Lmat = NULL)

2. View results

results$estimated_length_par results$estimated_froese_par

3. Assess stock status

StockStatus <- FishSS(data = CPdata, LM_ratio = results$LM_ratio, Pmat = results$estimated_froese_par[1,2], Popt = results$estimated_froese_par[2,2]) How to Cite If you use aLBI in your research, please cite both the software and the methodology paper:

Journal Article:

Ali, A., Sarker, M. R., & Alam, M. S. (2025). Development of a simple R package (aLBI) for the estimation of stock status from the length frequency data. Fisheries Research, 288, 107467. https://doi.org/10.1016/j.fishres.2025.107467

Software:

Ali, A., & Alam, M. S. (2024). aLBI: Estimating Length-Based Indicators for Fish Stock (Version 0.1.9).

Contact Ataher Ali – University of Chittagong, Bangladesh

Email: ataher.cu.ms@gmail.com

GitHub: Ataher76