PURSE SEINE FISHING
Elizabeth Barry, Anna Mason, Lisa Knocke
Picture of Net
General Notes about Purse Seine Fishing
- According to the International Seafood Sustainability Foundation (ISSF), “Purse seine fishing vessels catch nearly 62% of the 4.2 million tons of tuna caught globally every year.”
- Can reach up to/more than 6,500 feet, varying in mesh size+overall size, (depending on target species)
- Average of bycatch is less than 1% (for tuna)
Where Purse Seine Fishing is used
- Common all over the world
- Upper levels of sea water is most common
- Fish that are in 300 m of water can be targeted
- Deep enough where the net can function properly (because of size)
- Usually miles off shore
How Purse Seine Fishing works:
- Floats along the top and when fish are located net encircles the school with the net, then the lead line is pulled in which closes the bottom preventing the fish from escaping out the bottom, then brought up onto boat or on side of boat
For example: when school of tuna is located in spot→ purse seine traps tuna and catches them
Consistent and efficient method
Vessels have two main fishing catching methods by catching fish either by themselves which is also known as “free-swimming schools” or also by taking advantage of large floating objects (like FADs) → that attract large schools of fish
not just large man-made objects, but also large dead floating animals
this benefits a vessel’s chance of catching fish in one catching
Types of fish/shellfish that are harvested with Purse Seine Fishing:
- Hardest part is finding school of fish
cues for fish: birds hovering over, water splashing, helicopters often scan the water above, also using radars to find fish (tells location and size)
Type of fish: “schooling pelagic fish of all sizes”, small sardines-large tuna fish, squid
- Common locations: US water, Hawaii, Alaska
This is a picture of a tuna, which is a common target of purse seine fishing.
How does Purse Seine Fishing harm or benefit the ecosystem:
- It can do a certain amount of damage-bycatch(no way to control what is being caught) but the bycatch rate is less than 1% so not a large problem
Ways of mitigating the effects of Purse Seine Fishing
Because the majority of bycatching by purse sein is when nets are left out for other species to swim into, Instead of just letting the net hang and wait, responsible fisherman only put out the net once a large school of the target fish is spotted. This way the net is in the water for a minimum amount of time so that only the intended species is captured
Does the government regulate your harvest or the devices used for harvest?
Bycatch numbers for Purse Seine Fishing
Purse seine fishing has an average bycatch rate that is less than 1%; however, the bycatch rate for purse seiners ranges from around 2% in the western and central Pacific Ocean to nearly 8% in the Atlantic Ocean. Also, despite efforts to decrease dolphin bycatch, dolphins are still getting hurt. This is mostly due to dolphins swimming with the schools of tuna.
What would happen if the government banned this type of commercial harvest?
Is Purse Seine Fishing environmentally sustainable? Why or why not?
If your fishing practice is harmful for ecosystem health, what are some alternatives seafood choices for consumers?
Other seafood options: choosing fish that aren't very popular at the same yet are safe to yet, shellfish, fish that aren't caught through purse seine fishing technique
Find out more at:
This is a picture of the process of purse seine fishing.
Blue Fin. Digital image. Wikimedia. N.p., n.d. Web. 9 Mar. 2015.
Hauling a Purse Sein. Digital image. Britannica, n.d. Web. 9 Mar. 2015.
Purse Sein Fishing. Digital image. Good Fish Bad Fish. N.p., n.d. Web. 5 Mar. 2015.
Purse Sein Model. Digital image. NOAA Fisheries. NOAA, n.d. Web. 5 Mar. 2015.
"Purse Seine – International Seafood Sustainability Foundation." Purse Seine – International Seafood Sustainability Foundation. N.p., n.d. Web. 10 Mar. 2015.
"Purse Seine: Fishing Gear and Risks to Protected Species." NOAA Fisheries. NOAA, n.d. Web. 10 Mar. 2015.
"Sustainable Fishing." - National Geographic Education. N.p., n.d. Web. 08 Mar. 2015.
"Sustainable Fishing Methods." Sunset. N.p., n.d. Web. 10 Mar. 2015.
"Tuna Company, Fishermen and Environmental Groups Squabble over Unpublished Fishing Decree." The Tico Times. N.p., 10 Mar. 2015. Web. 10 Mar. 2015.