Final

1 collaborator

Yun Zhou (Author)

WHAT IS IT?

This is a model simulating a marine ecosystem and let users try several human activities and see the result returned by the model. Details: In my models, there are two main focuses. The first is how would human beings’ behaviors impact on the ecosystem at continental shelf. In this study, I involved in 3 factors in total: building an island on the sea surface, fishing with boats moving around, emit wastes and pollution to the sea. The second is the fishes’ behavior. In this study, I implemented a lot of fishes’ normal habits and its relationship with predators. I observe their moving patterns under several varied different situations.

HOW IT WORKS

Rules For forage fishes: it has the option to form a flock to act and move together which in the real world would help fish for reducing the resistance produced by water and would also help forage fishes to escape from its predators. Besides the flock feature, the fishes can also choose avoid action to detect nearby predators and escape to another direction. Every move would reduce their energy by one and if the possibility is big enough, they can reproduce which would cost them half energy. The hatch number is controlled by the fish-reproduce-percent slider. The fishes can eat seaweed and gain energy. And the energy is also determined by a slider named fish-gain-from-food. For predators: They can chase after the forage fishes for food and if there is no fish nearby but some other predators nearby, they would fight with each other and one of them would die. Predators can eat fishes to gain energy and reproduce at a certain possibility that would lose half of its energy. If the age of predator is over 10 or its energy is less than 5, it would die. Every move would also make predator’s age plus one.

For human-beings: there is an option to decide whether the human would be involved in this ecosystem. If human-involved is false, the system would only have predators and forage fishes which would form a balanced ecosystem. If human-involved is true, the system would have boats moving around and catching predators and fishes. The boats’ speed is higher than fishes and when there is a predator nearby, the boat would prefer catching a predator rather than all the fishes in radius 3. For plankton: Their color is green. Forage fishes are feed on the planktons. And planktons can regrow randomly in a certain amount of time. When they are eaten by the fishes, they would disappear and pcolor would go back to blue.

Activities Drawing an island: The users can turn a patch into color red, which means building an island on the ocean. These parts are not accessible by any kinds of fish or boats. We can use this feature to study how would the size of the island effect all the ecosystem around continental shelf. Emit pollution: The users can turn a patch into color grey, which means make that part of ocean too dirty for plankton to live on. So at the grey patches, plankton would not grow there. However, the ocean has an ability to clean it self. When the water turns back to blue the plankton would regrow again. Fish migrations: The users can turn a patch into color pink, which means it is a place for forage fishes to reproduce. No forage fish can reproduce at plankton or blue. We can draw several sources for fishes and observe their movings.

HOW TO USE IT

The first step to study how will human would affect a system, we need to have the precondition that the whole ecosystem is balanced. So first, we have to set my model to be balanced only with the fish, predators and planktons. This is easy to achieve. For second step, we can try flock? slider or chase? Slider to see whether these natural features would make one side has any advantage. For third step, we can draw island on the screen and see how the size of the island affects the whole ecosystem. For the following steps, we can try draw the source for forage fishes or draw the pollution. Then we can combine these three features to see the impact. For example, we can draw the island surround the reproduce source which makes no forage fishes can reach the source for reproducing and see what is the result. Or we can draw four sources and a straight island cross them. There are a lot of interesting features and phenomena exist in my model.

THINGS TO NOTICE

When we want to circle a piece of island, we have to make sure there are no cracks.

THINGS TO TRY

We can draw the island surround the reproduce source which makes no forage fishes can reach the source for reproducing and see what is the result. Or we can draw four sources and a straight island cross them. Details have been writen in the how to use it.

EXTENDING THE MODEL

May be would add the marine current flow in which would change the distributions of the planktons in the future.

NETLOGO FEATURES

(interesting or unusual features of NetLogo that the model uses, particularly in the Code tab; or where workarounds were needed for missing features)

RELATED MODELS

(models in the NetLogo Models Library and elsewhere which are of related interest)

CREDITS AND REFERENCES

(a reference to the model's URL on the web if it has one, as well as any other necessary credits, citations, and links)

Comments and Questions

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Click to Run Model

breed [fishes fish]
breed [predators predator]
breed [boats boat]
breed [detritus detritu]

turtles-own [ age  flockmates  nearest-neighbor energy]
patches-own [plankton polution ]
globals [ timenum]

to draw-island              ;; draw island
  if mouse-down?     ;; reports true or false to indicate whether mouse button is down
    [
      ;; mouse-xcor and mouse-ycor report the position of the mouse --
      ;; note that they report the precise position of the mouse,
      ;; so you might get a decimal number like 12.3, but "patch"
      ;; automatically rounds to the nearest patch
      ask patch mouse-xcor mouse-ycor
        [ set pcolor red ]
    ]
end 

to draw-source        ;;draw the source of reproduce
  if mouse-down?     ;; reports true or false to indicate whether mouse button is down
    [
      ;; mouse-xcor and mouse-ycor report the position of the mouse --
      ;; note that they report the precise position of the mouse,
      ;; so you might get a decimal number like 12.3, but "patch"
      ;; automatically rounds to the nearest patch
      ask patch mouse-xcor mouse-ycor
        [ set pcolor pink ]
    ]
end 

to draw-polution      ;; draw the pollution area
  if mouse-down?     ;; reports true or false to indicate whether mouse button is down
    [
      ;; mouse-xcor and mouse-ycor report the position of the mouse --
      ;; note that they report the precise position of the mouse,
      ;; so you might get a decimal number like 12.3, but "patch"
      ;; automatically rounds to the nearest patch
      ask patch mouse-xcor mouse-ycor
        [ set pcolor grey ]
    ]
end 

to setup
  clear-all
  ask patches  [                 ;;set up the planktons
    set pcolor blue
    set plankton random sea-regrow-time
    set pcolor one-of [green blue]
  ]
end 

to create
  
  create-fishes number-of-fish [           ;;create certain numbers of forage fishes
    setxy random-xcor random-ycor
    set color red
    set shape "fish"  
    set age random 3
    set energy random random (2 * fish-gain-from-food)
    let x 0
    let y 0
    ask one-of patches with [pcolor != red]
    [
      set x pxcor
      set y pycor
    ]
    setxy x y
  ]
  
  

  
  create-predators number-of-predator [          ;;create certain numbers of predators
    setxy random-xcor random-ycor 
    set color yellow
    set shape "shark"
    set age random 5
    set energy random  (2 * predator-gain-from-food)
    set size 1.5 ;; increase their size so they are a little easier to see
    let x 0
    let y 0
    ask one-of patches with [pcolor != red]
    [
      set x pxcor
      set y pycor
    ]
    setxy x y
  ]
  if human-involoved?                       ;;if human being involved, create certain numbers of boats
  [ create-boats boats-number [  
    let x 0
    let y 0
    ask one-of patches with [pcolor != red]
    [
      set x pxcor
      set y pycor
    ]
    setxy x y
    set color white
    set shape "boat"  
    set size 2
  ]]
  
  reset-ticks
end 

to go
 
  if not any? turtles [  
    stop
  ]
  
  ask fishes [
    ifelse flock? [                     ;; check if the forage fishes would go in the pattern as a flock
      flock
      avoid                          ;;forage fishes would escape if there is any predators around
     ; move
      ; fd 1
      ;   set age age + 1
      set energy energy - 1
      
    ]
    [ avoid
      
      ;move
      
      ; set age age + 1
      set energy energy - 1
    ]
    eat-plankton         ;;eat food and gain energy
    check-fish-dead       ;;check if the forage is dead or not
    
    fish-reproduce        ;;fish reproduce 
    
  ]
  

  
  
  ask predators [                  ;; ask predators to eat forage fishes and gain energy
    
    
    eat-fish
    
    
    set energy energy - 1
    check-if-dead
    set age age + 1
    predator-reproduce          ;;predator reproduce
  ]
  
  
  if human-involoved?
  [
    ask boats [
      move
      
      fishing           ;;human go fishing
    ]
  ]
  
  regrow-plankton        ;; regrow the plankton
  
  
  tick  
  my-update-plots
end 

to flock  ;; turtle procedure
  find-flockmates
  if any? flockmates
    [ find-nearest-neighbor
      ifelse distance nearest-neighbor < 0.75
        [ separate ]
        [ align
          cohere ] ]
end 

to find-flockmates  ;; turtle procedure
  set flockmates other turtles in-radius 3
end 

to find-nearest-neighbor ;; turtle procedure
  set nearest-neighbor min-one-of flockmates [distance myself]
end 

to separate  ;; turtle procedure
  turn-away ([heading] of nearest-neighbor) 3.50
end 

to align  ;; turtle procedure
  turn-towards average-flockmate-heading 5
end 

to cohere  ;; turtle procedure
  turn-towards average-heading-towards-flockmates 5.75
end 

to turn-towards [new-heading max-turn]  ;; turtle procedure
  turn-at-most (subtract-headings new-heading heading) max-turn
end 

to turn-away [new-heading max-turn]  ;; turtle procedure
  turn-at-most (subtract-headings heading new-heading) max-turn
end 

to turn-at-most [turn max-turn]  ;; turtle procedure
  ifelse abs turn > max-turn
    [ ifelse turn > 0
      [ rt max-turn ]
      [ lt max-turn ] ]
    [ rt turn ]
end 

to-report average-flockmate-heading  ;; turtle procedure
                                     ;; We can't just average the heading variables here.
                                     ;; For example, the average of 1 and 359 should be 0,
                                     ;; not 180.  So we have to use trigonometry.
  let x-component sum [dx] of flockmates
  let y-component sum [dy] of flockmates
  ifelse x-component = 0 and y-component = 0
    [ report heading ]
    [ report atan x-component y-component ]
end 

to-report average-heading-towards-flockmates  ;; turtle procedure
                                              ;; "towards myself" gives us the heading from the other turtle
                                              ;; to me, but we want the heading from me to the other turtle,
                                              ;; so we add 180
  let x-component mean [sin (towards myself + 180)] of flockmates
  let y-component mean [cos (towards myself + 180)] of flockmates
  ifelse x-component = 0 and y-component = 0
    [ report heading ]
    [ report atan x-component y-component ]
end 

to avoid ;; android procedure
  let candidates patches in-radius 1 with [ not any? predators ]        ;;if there is any predators around
  ifelse any? candidates
    [ face one-of candidates ]
    [ 
      let wall? false                              ;; check if there are walls ahead
      ask patch-ahead 1[
        if(pcolor = red)
        [
          set wall? true
        ]
      ] 
      ifelse (wall?)
      [
        rt random 360                              ;;if there are walls between walls between predators and fishes, random move
        move
      ]
      
      [ rt (random 3) * 90 
        
        ask patch-ahead 1[                 ;;else random pick a direction and escape
          if(pcolor = red)
          [
            set wall? true
          ]
        ] 
        ifelse (wall?)                       
        [
          avoid
          
        ]
        [forward 1  ]]]                  ;;if there are no predators around, move.
end 

to chase                    ;;let predators chase after forage fishes for food
  ifelse any? fishes in-radius 2
    [ let candidates one-of fishes in-radius 2
      let wall? false                 ;;if there are forage fishes nearby
      ask patch-ahead 1[
        if(pcolor = red)
        [
          set wall? true                ;;check if there are walls between them
        ]
      ] 
      ifelse (wall?)
      [
        rt random 360       ;;if there are walls, random move
        move
      ]
      
      [
        face candidates           ;;if there are no walls, face the forage fish and move
        set energy energy - 1
        fd 1
      ]   
      
    ]
  
    [ if random 100 < predator-fight-percent          ;;if there are no forage fishes around, they might fight for their space
      [fight ] ]
end 

to polution-on
;  ifelse ticks != nobody
 ; [set timenum ticks]
  ;[set timenum 0]
  set timenum ticks
  let polution-factor random 10
  ask patches with [pcolor = grey]
  [ set polution polution-factor
    ]
end 

to self-restore                         ;;self restore the pollution emitted into the ocean
  clean
  tick
end 

to clean                             ;;check if it has passed enough time to let ocean clean the pollution
  let now ticks
  if now = timenum + 3000
  [
    ask patches with [pcolor = grey]
    [set pcolor blue]]
end 

to fight                                  ;; predators fight each other when there are not enough food around for their place
  ifelse any? predators in-radius 1
  
  [let candidates one-of predators in-radius 1  
    set energy energy - 4
    face candidates
    let walls patches in-radius 1 with [pcolor = red]
    ifelse any? walls                  
    [
      move]
    [forward 1  ]
    ask candidates [ die ]                  ;;one of the predators would die in this fight and the other one would loose a lot of energy also
    
  ]
  [ move
    set energy energy - 2]
end 

to eat-plankton                         ;;forage fishes eat plankton
  if ( pcolor = green) [
    set pcolor blue         
    set energy energy + fish-gain-from-food
  ] 
end 

to eat-fish                           ;;predators eat forage fishes
  ifelse any? fishes in-radius 1 [ 
    ask fishes in-radius 1 [     
      die
    ]
    set energy energy + predator-gain-from-food
  ]
  
  [ 
    if chase?                    ;;if there are no food around, look further and chase
    [chase]]
end 

to fishing                       ;;human go fishing
  if random 100 < 70
    [
      ifelse prefer-big? [             ;;if human are prefer fishing the predators, they would catch one predator rather than all the nearby fishes
        ifelse any? predators-here [
          let target one-of predators
          ask target [
            die
          ]]
        [ ask fishes in-radius 3 [
          die
        ]
        ]
      ]
      
      [ ask fishes in-radius 2 [
        die]
      
      ]]
end 

to fish-reproduce
  ifelse produce-source?                  ;;let fish reproduce. If there required a reproduce source, make the forage fishes can only reproduce at certain place
  [
    let location false                  ;;so every time fish want to reproduce, they have to move towards those sources
    ask patch-here[
      if  pcolor = pink                 ;;and hatch their childeren out side the walls
      [ set location true
      ]]
    
    ifelse location != false
      [  
        if random 100 < fish-reproduce-percent [
          set energy (energy / 2)
          move
          move
          hatch fish-hatch-number [
            hatch 1  [ 
              rt random-float 360 
              let wall? false
              ask patch-ahead 1[
                if(pcolor = red)
                [
                  set wall? true
                ]
              ] 
              ifelse (wall?)
              [
                rt random 360
                move
              ]
              [ fd 1]]]
          
        ]]
      [ 
        
        trace-back ]]            ;;the moving towards sources procedure
  [  if random 100 < fish-reproduce-percent [        ;;otherwise, just normal reproduce. Can happen at any place
    
    set energy (energy / 2)
    hatch fish-hatch-number [
      hatch 1  [ 
        rt random-float 360 
        let wall? false
        ask patch-ahead 1[
          if(pcolor = red)
          [
            set wall? true
          ]
        ] 
        ifelse (wall?)
        [
          rt random 360
          move
        ]
        
        [forward 1  ] ] ]
    
    
  ]
  ]
end 

to trace-back
  let x 0                   ;;find the way back to the sources and reproduce
  let y 0
  let candidates one-of patches with [pcolor = pink]
  if candidates != nobody
    [ ask one-of patches with [pcolor = pink]
      [
        set x pxcor
        set y pycor
      ]
    facexy x y
    let wall? false
    ask patch-ahead 1[
      if(pcolor = red)
        [
          set wall? true
        ] 
    ] 
    ifelse (wall?)
      [
        rt random 360          ;;if there are walls on them way, they would try to find another path
        move
      ]
      [ fd 1]]
end 

to predator-reproduce              ;;predators' reproduce, the same with the normal forage fishes' reproduce
  if random 100 < predator-reproduce-percent and energy > 60[
    set energy (energy / 2)
    hatch 1  [ 
      rt random-float 360 
      let wall? false
      ask patch-ahead 1[
        if(pcolor = red)
        [
          set wall? true
        ]
      ] 
      ifelse (wall?)
      [
        rt random 360
        move
      ]
      
      [forward 1  ] ] 
    
  ]
end 

to check-if-dead          ;;check whether the predators are dead
  if energy < 5 and age > 10[
    if random 100 < 62
    [
      
      die
      ;ask detritus [hatch 2]
    ]
  ]
end 

to check-fish-dead     ;; check whether the forage fishes are dead
  if energy < 1 [
    die
  ]
end 

to regrow-plankton      ;;regrow the planktons after certain amount of time and possibilities
  ask patches with [ pcolor = blue][
    if  random 100 < sea-regrow-time
      [ set pcolor green
        set plankton sea-regrow-time]]
  
  ask patches with [pcolor = green]   [set plankton plankton - 1]
end 

to my-update-plots
  set-current-plot-pen "fish"
  plot count fishes
  set-current-plot-pen "shark"
  plot count predators  ;; scaling factor so plot looks nice
  set-current-plot-pen "plankton"
  plot sum [plankton] of patches / 30 ;; scaling factor so plot looks nice end
end 

to boat-move        ;;let boats moving around without hitting the walls
  rt random 360
  let wall? false
  ask patch-ahead 1[
    if(pcolor = red)
    [
      set wall? true
    ]
  ] 
  ifelse (wall?)
  [
    rt random 360
    move
  ]
  
  [forward 1  ]
end 

to move            ;;let turtles moving without hitting the walls
  rt random 360
  
  let wall? false
  ask patch-ahead 1[
    if(pcolor = red)
    [
      set wall? true
    ]
  ] 
  ifelse (wall?)
  [
    rt random 360
    move
  ]
  
  [forward 1  ]
end

There is only one version of this model, created over 12 years ago by Yun Zhou.

Attached files

File	Type	Description	Last updated
Additional model.nlogo	extension	addition model	over 12 years ago, by Yun Zhou	Download
EECS 472 Final Project Progress Report.pdf	pdf	process report1	over 12 years ago, by Yun Zhou	Download
EECS 472 Final Project Progress Report2.pdf	pdf	process report2	over 12 years ago, by Yun Zhou	Download
EECS 472 Final Project Progress Report3.pdf	pdf	process report3	over 12 years ago, by Yun Zhou	Download
EECS 472 Final Project Progress Report4.pdf	pdf	process report4	over 12 years ago, by Yun Zhou	Download
Final Paper.pdf	pdf	final paper	over 12 years ago, by Yun Zhou	Download
Final.png	preview	Preview for 'Final'	over 12 years ago, by Yun Zhou	Download
HubNet.nlogo	extension	hubnet	over 12 years ago, by Yun Zhou	Download
present.pptx	powerpoint	present slides	over 12 years ago, by Yun Zhou	Download
User Guide.pdf	pdf	user guide	over 12 years ago, by Yun Zhou	Download

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