Yellowfin Tuna in Costa Rica

What yellowfin tuna are

The yellowfin tuna (Thunnus albacares) is a torpedo-shaped ocean fish built for speed and endurance. It has a metallic dark blue back, a gold stripe along its side that fades after death, silver below, and bright yellow finlets edged in black. In big adults the second dorsal fin and the anal fin grow into long yellow sickles, and the long pectoral fins usually reach past the start of the second dorsal fin.

FishBase lists a maximum of 239 cm fork length and 200 kg. Most fish caught on Costa Rican charters are much smaller, from school fish of a few kilos to fish well over 50 kg on a good day offshore. MarViva's guide describes yellowfin as the most common tuna in Costa Rican offshore waters, present all year, and as a species that's only recently become a sport target here.

Where to find them in Costa Rica

Yellowfin roam the open Pacific and come and go with water temperature and bait. Boats from every Pacific port catch them, but the deep water off the southern Pacific has a reputation for large fish: Crocodile Bay, near Puerto Jiménez, reports yellowfin of about 45 to 115 kg (100 to 250 lb) around December and January. They're also caught off Guanacaste and the central Pacific, and offshore around seamounts and floating objects.

Crews look for three signs: diving seabirds, schools of spinner dolphins, and tuna busting bait at the surface. In the Eastern Pacific, big yellowfin often travel with dolphin pods, so finding the dolphins is often the first step to finding the tuna.

Best months

Yellowfin are here all year, and MarViva's fisheries data shows steady numbers across the months. For sport catches:

• Adventure Tours Costa Rica, on the central Pacific, reports the best yellowfin from January to July, with bigger fish in spring and early summer.
• FishingBooker's month-by-month guide puts the best season from May to September.
• Crocodile Bay, in the south, reports big tuna at several points in the year and the most consistent action in November and December.

The overlap points to about May to August as the best months, with good fishing at other times. See the season chart for the full year.

How crews fish for them

Once a crew finds birds or dolphins, there are a few ways to get a bite:

• Trolling lures such as cedar plugs, feathers, small skirted lures and diving plugs around the edge of the school.
• Live bait, usually a small bonito or a sardine, slow-trolled or drifted near the fish.
• Casting poppers and stickbaits into surface feeding frenzies, or vertical jigging when the fish are deeper.

Tackle depends on the size of the fish around. Medium spinning gear handles school fish; for the big ones, crews use 50 to 80 lb class stand-up gear with a harness. A large yellowfin dives deep and circles under the boat, so expect a tiring fight. Ask your crew to stay well back from dolphin pods and not to drive through them.

The rules

Yellowfin aren't a catch-and-release species in Costa Rica. The fisheries regulation (Decreto 36782, article 68) allows 5 fish per trip to be landed for your own use or taxidermy and bans selling sport catches. INCOPESCA's legal first-capture size for yellowfin sold in Costa Rica is 60 cm (agreement AJDIP/026-2018), so releasing small tuna is the right thing to do.

Everyone fishing from a boat needs an INCOPESCA sport fishing licence (Ley 8436, article 75), available in 8-day, 30-day and 1-year versions. Many charter operators can arrange it.

Eating quality

Yellowfin is one of the finest eating fish there is. The deep red loin is eaten raw as sashimi or poke, seared rare, or grilled. Bleed and ice the fish as soon as it's landed for the best quality, and your crew will know the routine. Keep only what you can eat, and release the rest.