rearing_growth: Rearing growth
In fishsciences/YoloBypassSBM: Yolo Bypass Salmon Benefits Model

Returns final wet_weight given initial wet_weight, model day, and duration

1	rearing_growth(water_year_string, date_index, duration, location, wet_weight)

`water_year_string`	Water year (1997-2011) as a string
`date_index`	Index of date in a water year at start of rearing period; in all years except WY1997, equivalent to day of water year
`duration`	Duration (days) of rearing period
`location`	Rearing location: Yolo or Delta
`wet_weight`	Wet weight (g) at start of rearing period