For spanish longliners: http://www.iccat.int/Documents/CVSP/CV062_2008/no_6/CV062061793.pdf

For Peruvian artisanal longliner we used:   Jumbo squid in pieces,  mackarel

Market prices and/or seasonal availability often determine this.  I've worked on several boats and used Brevoortia, Scomber, Loligo, Euthynnus and various elasmobranch species (on sets that were targeting sharks).

Scomber scombrus in Portugal, Spain and France especially for swordfish and tuna species. 

Scomber scombrus in Italy for large pelagics as swordfish and tuna species, including thynnus thynnus.

Some Indian fishermen have their own unique method in catching live bait fishes,which are small pelagics.They tie 19 no.fish hooks 4 in nos.to each side of a 3 inch long bamboo piece almost 1.5 cms. in square section with polyamide string.Each of these "Nangura Chunda" (the local name) is tied to a long bamboo pole some 15 to 20 feet long with polyamide strings,with the hooks immersed in top surface layers of running fishing vessel.Such a vessel may have some 5 to 10 poles on each side. Depending upon the place & season,small pelagics catch the bait & these are kept live in a separate sea water tank on the vessel. Catching of this bait fishes is continued all the 24 hrs.in a day till they reach the fishing area.

At Azores they use living bait, mainly small pelagic such as Trachurus picturatos, Sardina pilchardus, Scomber japonicus, Pagellus bogaraveo, Boops boops, Macroramphosus scolopax and Capros aper, which are captured mainly by purse-seine fishery

Pelagic longline fisheries in Cyprus aiming swordfishes and albacores are using mainly Sardina fish...

For blue sharks Prionace glauca, spanish fishermen use like bait Longfin squid Loligo pealei but scomber scombrus for swordfish Xiphias gladius and shortfin mako Isurus oxyrinchus

You might want to contact the 8 Regional Fishery Management Councils in the U.S. to get a comprehensive response for U.S. longline fisheries, in addition to the responses you've already received. 

We have a study on surface longline bait from the Spanish longline fleet in the Mediterranean:

Báez et al. (2010). Captures of swordfish Xiphias gladius Linnaeus 1758 and loggerhead sea turtles Caretta caretta (Linnaeus 1758) Associated With Different bait combinations in the Western Mediterranean surface longline fishery. J. Appl. Ichthyol. 26: 126-127

Globally, bait species used in longline fisheries are highly variable depending on fleet, species targeted, local bait availability, imported bait availability and prices. I would suggest to you either to develop a deep bibliographic survey in longline fisheries publications or to distribute a specific questionnaire, than to pose such question on Research Gate. Responses you’ll get from a couple of scientists based on limited local knowledge may heavily deviate from global average. In general tuna fishing fleet use small pelagics as bait; such as: Cololabis saira, Scomber scombrus, Scomber japonicus, Sardina pilchardus, several species of Decapterus and Trachurus. Pacific fleets widely use locally produced milkfish Chanos chanos. Swordfish targeting fleets usually use squid bait, however many tuna fleets use squids as secondary or primary bait also. Squids for bait mostly originate from jig fisheries, usually from Southwestern Atlantic: Illex argentinus. However trawl-caught species like Nototodarus spp from New Zealand also used despite lower quality of trawl-caught squids. Other Illex species or mass species like Todarodes pacificus often used locally or internationally. Finally some swordfish targeting fleets use fish bait Scomber spp also. This is complex question, therefore and detailed study of fleets and markets is probably necessary. In addition I am not talking about demersal longline fisheries that also widespread around the World and use variety of species for bait. Hope this helps.

In Alaska squid and herring are common baits.

In Brazil, the most common baits are the Atlantic chub mackerel (Scomber colias), the Argentine shortfin squid (Illex argentinus), the Brazilian sardine (Sardinella brasiliensis), and occasionally chunks fo fish (Ruvettus pretiosus, Lepidocybium flavobrunneum)

In India, south west coast (Lakshdeep)  area tuna catch is more, for catching tuna by long line sardine fish use as bait, it is very cheap and easily available so.

It was known that the Taiwanese fishing boats used milkfish, moonfish, silvercarp etc. currently it was the squids that used mostly due  low prices. my feeling had been that  any kind that has light reflection, or chemical illuminant within dark and those release fishy smelts and with long lasting muscle tissue  are mostly preferred.

In Mediterranean Spanish coasts the use of Illex coindetii, Sardinella aurita or Scomber scombrus are common for longline fisheries. It depends on market price of these baits.

As for the Spanish longline fisheries, also the Italian longlines fisheries (most are Sicilians)  use Scomber scombrus, Sardiinella aurita and Illex coindetii, depending on their market price. Large longlines prefer scomber scombrus and sardinella aurità. .

I agree with Sergio Trigos and Massimo Spagnolo, in the Mediterranean Spanish coasts the most common bait is Scomber scombrus and Sardinella aurita, but also Todarodes spp. and Sardina pilchardus.

I'm sorry I leave the subject, but did you see these article? It is interesting to anyone who uses this type of fishing.

http://www.academia.edu/6783812/Effect_of_type_of_bait_on_pelagic_longline_fishery-loggerhead_turtle_interactions_in_the_Gulf_of_Gabes_Tunisia

Not longline, but for an excellant review of global use of baitfish in pole and line tuna fisheries, see: Gillett, R. 2012. Report of the 2012 ISSF Workshop: The Management of Tuna Baitfisheries: The Results of a Global Study. ISSF Technical Report 2012-08. International Seafood Sustainability Foundation, Washington, D.C., USA.

In Taiwan, mackerel, squid, saury and milkfish are the baits commonly used in the pelagic tuna longline fisheries. 

In Brazil, bait of Sardinella brasiliensis is used on skipjack fishing with rod and bait alive.

Indian Mackeral is ideal for tuna longlining but as this resource its self is costly in India, we go for some imported black fish from Japan.

In the Spanish Mediterranean surface longline fisheries they use many different baits and baits combinations. Also it is important the hook type/size combined with the baits... A doc on baits and hooks combinations was mentioned by Baez and here are attached.

In Brazil are used Chub Mackerel (Scomber japonicus), squid (Illex argentinus), Sardinella brasiliensis and Atlantic Little Tuna(Euthynnus alletteratus) as bait in the pelagic longline fishery.

In Bay of Biscay , surface longline fisheries (from Yeu) use differents sort of baits as makerels (scomber scombrus, Scomber japonicus) and also Broadtail squid (illex coindetti), but all depending of their prices and availabilty.

Hello everyone.

Basically, small pelagics. Came from fisheries or aquaculture. Here in Brazil some projects tried to use tilapia figerlings. however, there is not allowed yet.

Costa Rica, Balistidae pelagic and coast are very good for yellowfin tuna, blue runner (Carangidae), Rainbow runner (Carangidae) other little tuna.  

Information on the source of bait used in pelagic longline fisheries can be found in Marine Stewardship Council public certification reports - which you can access from the MSC.org website.