# Features

### Growth and length-weight relationship

Compute the von Bertalanffy growth function, growth performance indices
and compare different growth curves. Fit the length-weight relationship
by model I and model II linear regression and nonlinear least squares.

### Reproduction and recruitment

Calculate age and length at first maturity by probit regression. Compute
spawning potential ratios (SPR). Determine recruitment variability from
catch-curve regressions and fit stock-recruitment relationships.

### Mortality

Compute total mortality rates by catch-curve, Jones and Van Zalinge plot
and Hoenig equation. Estimate natural mortality rates by several indirect
methods.

### Virtual population methods

Perform virtual population analysis (VPA) by solving classic catch equation
(Gulland) on catch-at-age data or cohort analysis on catch-at-length data
(Jones). Compute predictive Thompson and Bell model and find the factor
that maximizes yields.

### Beverton and Holt yield-per-recruit model

Compute biomass and yield-per-recruit from Beverton and Holt model by
numerical integration or Gulland approximation using weight based von
Bertalanffy growth function. Relative yields are also available. Find
Fmax and F0.1 and make isopleth diagrams.

### Selectivity

Compute "effective mesh size" from VPA or cohort analysis. Estimate
selection ogive from catch-curve.

### Monte Carlo methods

R has built in random number generation for Beta, Binomial, Cauchy,
Chi-squared, Exponential, F, Gamma, Geometric, Hypergeometric, Log-normal,
Logistic, Negative-binomial, Normal, Poisson, Student-t, Uniform, Weibull
and Wilcoxon distributions. FishAssess functions do not yet work in a
direct Monte Carlo manner, but with some knowledge of R language doing it
in a straightforward way is possible (i.e., one line combination of
functions).

**Continuously under construction...**