Elizabeth Barry, Anna Mason, Lisa Knocke

Picture of Boat with Net in Water

This a before and after picture of purse seine fishing when they trap the fish, and then collect them.
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Picture of Net

This is a picture of what exactly the net looks like that traps the fish. The bottom closes so that the fish cannot escape after being trapped in the 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

  • Oceanic
  • 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
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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?

The official stance of policy by the National Oceanographic and Atmospheric Association (NOAA) is that Fishers cannot set nets on dolphin pods in order to reduce cetacean bycatching. But since NOAA is only a national organization, it can only regulate fishing in national waters, so purse seining can be totally unregulated in other countries.

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?

If the government were to ban purse seine fishing the price of tuna would go up because it would take more time, effort and money to capture the amount of tuna we are able to get through the use of purse seine fishing; however, while the price of tuna would go up, the money made would stay -more- within the US, going to smaller fishing communities or fishermen instead of to big international fishers.

Is Purse Seine Fishing environmentally sustainable? Why or why not?

While purse seiner fishing is a very efficient way to catch a lot of fish, if it done consistently over a long period of time it can lead to overfishing -when fish are taken from the ocean faster than they can reproduce- and commercial extinction- when a species becomes too rare to catch profitably. Furthermore, the amount of bycatch has an effect on the environment. So, while purse seiner fishing is not the worst method of fishing, if it goes unregulated, it is no friend to the environment either.

If your fishing practice is harmful for ecosystem health, what are some alternatives seafood choices for consumers?

Because Purse seining has such a low bycatch rate, it is not hugely harmful, so there is not a large pull to boycott such a practice. A bigger problem would be overfishing, which is very much present in oceanic communities that are effected by purse fishing (especially if the population is small-harder to replenish itself). A way to avoid purse seining is to only consume non-schooling fish, because that is the only type of fish that are caught with purse seining. This would include fish like Tuna. This way the only fish that would be caught would be from either farming or small scale fishing that has virtually no by-catching involved.
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:
monoray seafood.inc

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This is a picture of the process of purse seine fishing.


Works Cited

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.