Change trends of fish composition and abundance in the fishing ground of set net


The spatial-temporal variations of the catch composition and abundance of the set net fisheries in the offshore waters around Taiwan could be one of the important indicators of the changes in the offshore epipelagic fishery resources.




production (tons)



Indicator Details


Fishery resources

PSBR model type

State (S)

Corresponding targets


Proportion of fish stocks within biologically sustainable levels

Aichi Biodiversity Targets

Target 6 By 2020 all fish and invertebrate stocks and aquatic plants are managed and harvested sustainably, legally and applying ecosystem based approaches, so that overfishing is avoided, recovery plans and measures are in place for all depleted species, fisheries have no significant adverse impacts on threatened species and vulnerable ecosystems and the impacts of fisheries on stocks, species and ecosystems are within safe ecological limits.


Set net fishing is a passive fishing method whose fishing effort can be calculated without complicated calibration. It takes advantage of the characteristic of highly migratory species along the coast: nets are set up on the necessary returning passage of the fish and the arrangement looks like a maze, which blocks the way of fish to get out once they are in the net maze. Currently, there are approximately 15 fishing grounds and 63 sets of nets in the coastal region around Taiwan, mainly in the Yilan and Hualien areas. The target fishes are skipjack tuna (Katsuwonus pelamis), bullet tuna (Auxis rochei), Mackerel tuna (Auxis thazard), ribbon fish (Trichiurus lepturus), and Common dolphinfish (Coryphaena hippurus).

Definition and Calculation

Fish composition and its abundance change trends of fishing ground of set net

  1. Collect long-term catch data from set-net fisheries around Taiwan.
  2. Select five dominant species and calculate their temporal change of the yield of catch (kg), the number of individuals, and the diversity index.


Current data is updated to 2017. The yeilds of catch of target fish species are: skipjack tuna 805.037 tons, bullet tuna 347.013 tons, mackerel tuna 520.592 tons, ribbon fish 268.813 tons, and common dolphinfish 238.112 tons.

Data Management Authorities

Fisheries Agency, Council of Agriculture

Data Source/URL

Fisheries Agency, Council of Agriculture

Data Development Status


Data Providers

Fishery annual report of the Fisheries Agency, Council of Agriculture; Database of the Association of Set Net

Investigation Year