Salmon migration in the Snake River

;: Created by Amy Steimke, Boise State University
;: Last edit: 12/8/2014

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;; PARAMETERS ;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; currently: 1 tick = 1 hour,
; each patch = 1 km ( with the exception of dams ) 

globals [ velocity
   ] ; average velocity of movement (km/hr), calculated in set-velocity procedure
           

turtles-own [ start-movement             ; true/false, says if they can start migrating
              movement-speed             ; fish's velocity, remains constant thru each run
              prob-death                 ; probability of death on any tick while migrating
              at-dam?                    ; if turtle is within 1 tick of a dam, goes to true
              time-at-dam                ; total time turtle spends at dams
              probability-of-passage ]   ; probability of passing through a dam

patches-own [ dam1   ; x-coordinate of Ice Harbor Dam (first one)
              dam2   ; x-coordinate of Lower Monumental Dam (second dam)
              dam3   ; x-coordinate of Little Goose Dam (third dam)
              dam4 ] ; x-coordinate of Lower Granite Dam (last one)


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;:::;;;;;;;;;;;;;;;;;::: SETUP ;:;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to setup
  clear-all
  reset-ticks
  file-close
  set-velocity
  setup-patches
  setup-turtles
  destroy-dams
end 


;;; creates river corridor and locations of dams ;;;

to setup-patches
  ask patches 
  [ set pcolor 55 ; sets up river banks
    set dam1 1    ; these 4 lines are x-coordinates of the dams
    set dam2 52
    set dam3 97
    set dam4 157
    if (pycor < 10) and (pycor > -10) [ set pcolor 105 ] ; sets up river corridor
    if (pxcor = dam1) [ set pcolor 2 ] ; sets up first dam
    if (pxcor = dam2) [ set pcolor 2 ] ; sets up second dam
    if (pxcor = dam3) [ set pcolor 2 ] ; sets up third dam
    if (pxcor = dam4) [ set pcolor 2 ] ; sets up last dam
   ]
end 


;;; sets average velocity for fish ;;;

to set-velocity
  ; velocity equation from Salinger & Anderson, 2006
  let flow (FlowRate-m3/s / 1000) ; flowrate in 10^3 m3/s
  let rivertemp (( RiverTemp-farenheit - 32 ) / 1.8 ) ; change river temperature to Celsius
    ifelse rivertemp <= 16.3
     [ set velocity ((27.3 + ( 2 * rivertemp ) - (1.5 * flow)) / 24)] ; velocity in km/hr for temperatures below 16.3C
     [ set velocity ((100.7 - ( 2.5 * rivertemp) - (1.5 * flow)) / 24)] ; velocity in km/hr for temperatures above 16.3C
end 


;;; sets up initial fish variables ;;;

to setup-turtles
  create-turtles initial-number-fish
  [
    set color red
    set shape "fish" 
    set size 2      
    setxy 2 8 - random(17)  ; places fish in starting corridor
    set heading 90
    set probability-of-passage probability-making-thru-dam
    set at-dam? false
    set time-at-dam 0
    set start-movement false
    set movement-speed random-normal velocity speed-stdev ; normally distributes speeds based off of calculated velocity and chosen stdev from slider on interface
    if movement-speed <= 0 [set movement-speed movement-speed * -1] ; makes sure movement-speed is not negative, otherwise error occurs while checking for dams and is unrealistic
 ]
end 


;;; procedure for destroying dams in the world, switches are on the interface ;;;

to destroy-dams
    if destroy-dam-2?        ; procedure for destroying 2nd dam
      [ask patches 
        [if pxcor = dam2
         [set pcolor blue]
        ]
       ]
    if destroy-dam-3?        ; procedure for destroying 3rd dam
      [ask patches 
        [if pxcor = dam3
         [set pcolor blue]
        ]
       ]
    if destroy-dam-4?        ; procedure for destroying 4th dam
      [ask patches 
        [if pxcor = dam4
         [set pcolor blue]
        ]
       ]
end 


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;; MOVEMENT ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to go
  tick
  start-migration
  move-turtles 
  fish-die
  if not any? turtles with [xcor < dam4]
      [stop]     ; stops ticking once all fish are past last dam
  check-for-dams
  dam-learn
end 


; procedure tells turtles when they can start moving, and when to stop movement after last dam

to start-migration
  ask turtles
  [
    if random-float 1 < probability-of-starting-migration  ; starts fish migrating
       [set start-movement true]
    if xcor > dam4 + movement-speed                        ; stops fish migrating
        [set start-movement false]    
  ]
end 


; procedure checks for dams ahead of turtle in the length of their movement-speed (only get stopped once by each dam)

to check-for-dams
  ask turtles
  [
    ifelse any? patches in-cone movement-speed 1 with [pcolor = 2] ; checks for dams ahead of them
    [set at-dam? true] 
    [set at-dam? false]
   if at-dam? = true 
   [set time-at-dam time-at-dam + 1]  ; calculates how many ticks they are stopped by dams
  ]
end 


; procedure calls for fish who have successfully navigated previous dams in a shorter period of time to have a 
; higher likelihood of navigating next dam they encounter more quickly

to dam-learn
  if dam-learning? ; switch is located on interface
  [ask turtles
    [ if at-dam? = true and xcor > dam2 and xcor < dam3 and time-at-dam <= 3      ; if second dam crossing took 3 or less ticks, they will get a higher probability for next dam
     [set probability-of-passage probability-of-passage * (random-float 1 + 1) ]  ; will multiply their previous probability anywhere from ~1.01 - 1.99
    
      if at-dam? = true and xcor > dam3 and xcor < dam4  and time-at-dam <= 5     ; if second & third dam crossings took 5 or less ticks, they will get a higher probability for next dam
     [set probability-of-passage probability-of-passage * (random-float 1 + 1) ]  ; will multiply their previous probability anywhere from ~1.01 - 1.99
    ]
      
  ]
end 
    

; procedure for movement; each tick turtles move their movement-speed (km/hr)
; if at-dam? is true for turtle, then turtle takes time trying to navigate/find fish ladder to cross dam 

to move-turtles
  ask turtles 
  [ if start-movement = true 
    [ ifelse at-dam? = false
    [ set heading 90 forward movement-speed] 
      [if random-float 1 < probability-of-passage ; set on interface tab, probability of fish finding the ladder
        [set heading 90 forward movement-speed] 
      ]
    ] 
  ] 
end 


; Procedure for fish to die on each tick with probability set on interface tab
; Mortality factors - fishing, disease, unsuccessful dam crossing

to fish-die
    ask turtles 
    [
      ifelse at-dam? = false 
              [if xcor <= dam4  
                 [set prob-death initial-mortality-constant] ; chance of dying on any turn
                  if xcor > dam4 [set prob-death 0 ] ; no death after the cross 4th dam
              ]
              [ set prob-death initial-mortality-constant * dam-death-multiplier ] ; higher likelihood of death while they are trying to cross dam  
    if random-float 1 < prob-death [die] ; death procedure
    ]
end 


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;; END ;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;