# Optimum Trophy Size Limits for Recreational Fisheries

### Description

Calculates optimum trophy catch over a range of F values and finds Fmax for a cohort given age-at-first recruitment, age-at-first-entry, and age at which fish are considered trophy size following Jensen (1981).

### Usage

1 2 | ```
opt_trophy(M = NULL, N = 1000, recage = NULL, entage = NULL,
trage = NULL, stF = 0, endF = 2, intF = 0.05)
``` |

### Arguments

`M` |
natural mortality |

`N` |
cohort size |

`recage` |
age-at-first recruitment |

`entage` |
age-at-entry into the fishery |

`trage` |
age of fish considered trophy size |

`stF` |
starting F of range to explore |

`endF` |
ending F of range to explore |

`intF` |
increment of F |

### Details

Calculations follow equations given in Jensen (1981).

### Value

`Catch` |
dataframe containing range of Fs and associated total catch and trophy catch of designated cohort size |

`Fmax ` |
F at which trophy catch is maximum |

### Author(s)

Gary A. Nelson, Massachusetts Division of Marine Fisheries gary.nelson@state.ma.us

### References

Jense, A. L. 1981. Optimum size limits for trout fisheries. Can. J. Fish. Aquat. Sci. 38: 657-661.

### See Also

`opt_slot`

### Examples

1 2 | ```
# Example from Jensen (1981) page 659
opt_trophy(M=0.70,N=1000,recage=1,entage=1,trage=4)
``` |