Topic outline

  • Measurement of flatfish samples from the fish market


  • Survey and research of marine resources

    • ·   Biological characteristics of fish fish landed to the market　

                  ⇒ Useful in estimating stock status

      ·   Body length composition: (crucial information)

                  ⇒ Gives some insight into the stock's status


    • Example-1

       

      ·  Modes showing age-0, -1, and -2 from left

      ·  These modes indicate age-1 to -3 years old if age-0 have not recruited yet

      ·  Older ages are unclear



    • Example-2

      ·  Age-1 should be a "strong year-class "

                   ・because fish number generally decrease as they grow

      ·  Few age >3  onward, perhaps because of

                     ·  Dispersed from fishing ground

                     ·  Reduction by catch


    •  Pay attention to the “size selectivity” of fishing gear!


  • Size (mesh) selectivity

    • 　

      Mesh size of the gill-net

      　

         Too coarse　　×

      　

         Too fine　×

      　　

      Catch fishes within the size range that matches the mesh size
      　


                                                        Gill-net: especially selective

      　

  • Experiment content

    • This is a video that explains the experiment.
      Students participating in this experiment should prepare by watching this video.

       An anatomical video is included.