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
· 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
· 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
- This is a video that explains the experiment.
Students participating in this experiment should prepare by watching this video.
An anatomical video is included.