More about one-by-one fishing

One-by-one tuna fisheries of the world

This working-map provides you with a visual representation of the location, relative size of the world's significant one-by-one tuna fisheries (pole-and-line, handline and troll). It also provides information on the fisheries certified by the Marine Stewardship Council and FairTrade. Please NOTE this live working map and this does not refer to ALL one-by-one tuna fisheries. 

The circle icons represent the locations of pole-and-line fisheries, square icons are troll fisheries and star icons are handline fisheries. The icon colours give an indication of the fishery’s catch in tonnes/year: white icons for less than 4999 tonnes/year; light blue for 5000-49999 tonnes/year and dark blue for greater than 50000 tonnes/year.

The information used to create this map was gained from a range of credible sources - references can be found on each individual data point. IPNLF will continue to update this map with information on one one-by-one fisheries. IPNLF very much welcome your input, comments and suggestions. If you have more recent or detailed information - get in touch!

We hope this resource provides a useful picture of the global extent of one-by-one fisheries.

How to fish tuna one-by-one

As its name suggests, one-by-one fishing is about one fisher using one line to catch one fish at a time (pole-and-line/handline) – something that requires great strength, skill and persistence by the fisher.

Many countries have a long and proud history of fishing for tuna in this traditional way. In fact, the origins of some one-by-one tuna fisheries date back several hundred years. Today, these traditional techniques are regarded as the most socially and environmentally responsible methods possible as they bring multiple benefits on the water and to coastal communities.

To give a better understanding of how these fisheries operate, we have summarised the one-by-one pole-and-line fishing process in this simple step-by-step guide:

  1. Baitfish – Vessels carry live bait to attract tuna to the boat. Traditionally, this bait is caught at night in inshore waters using a small lift net or seine net. These fish are then kept alive in bait wells within the boat.
  2. Locating – Vessel skippers often pinpoint tuna schools using seabirds or by sighting other fishing boats. Recently anchored Fish Aggregating Devices (FADs) are also used
  3. Chumming – On finding a shoal of tuna and positioning the boat nearby, the live bait is scattered into the sea. This is known as “chumming” and is usually carried out in conjunction with water sprinkling, which creates the illusion of a large school of small fish near the water’s surface. This sends the tuna into such a frenzy that they bite at any shiny, moving object, including the fishermen’s lures
  4. Catching – Barbless hooks with lures are used to fish tuna one-by-one. The hook size prevents the capture of small fish and by-catch
  5. Storage – To prevent spoilage, larger vessels store their tuna on capture in a refrigerated hold, while smaller vessels put the fish on ice in a hold after the decks have been cleared

One-by-one fishing technique vary according to country or region; for example, in the Maldives fishers cast their poles at the back of the dhoni (Maldivian fishing vessel), whereas in the US they fish from the side. 

The video below shows how fishers in the Maldives catch tuna using pole-and-line.

Pole-and-line fishing in action, Maldives 2014