Marlin in Costa Rica

Three marlins, one coast

Marlin are the heavyweights of Costa Rican sportfishing. All three species found here are billfish with a long rounded bill, a crescent tail and the strength to fight for hours on heavy tackle.

• Blue marlin (Makaira nigricans) is the one most crews mean when they talk about marlin. It's cobalt blue on top, silver-white below, with pale blue bars that light up when it's excited. FishBase lists a maximum of 5 m total length and a published weight of 636 kg.
• Black marlin (Istiompax indica) has stiff pectoral fins that can't fold flat against the body, which is the surest way to tell it from a blue. It's the largest of the three, with FishBase listing 465 cm fork length and 750 kg.
• Striped marlin (Kajikia audax) is slimmer, with a tall pointed dorsal fin and clear blue stripes on its sides. Most are much smaller than blues and blacks.

Fish of several hundred kilos are possible, but most marlin caught off Costa Rica are smaller than the record sizes. Your crew can give you a better idea of what's been biting.

Where to find them

Marlin are an offshore Pacific fish. Blue marlin roam the deep blue water and are often found well offshore around seamounts, current lines and schools of tuna. MarViva's guide notes that black marlin are found both offshore and closer to the coast and islands, and that striped marlin are present all year off Guanacaste and Isla del Coco.

All the main Pacific ports fish for them: Flamingo, Tamarindo and Papagayo in Guanacaste, Los Sueños and Quepos on the central Pacific, and Golfito and Puerto Jiménez in the south. MarViva records blue marlin off both coasts, but sport fishing for marlin in Costa Rica happens on the Pacific.

Best months

Marlin are caught every month, and the peaks depend on species and region.

• MarViva's fisheries data shows blue marlin most abundant from May to September and black marlin from May to October, with striped marlin peaking from July to October on the central and southern Pacific.
• Operators quoted in Sport Fishing Magazine's billfish guide put marlin peaks at November to December and July to September on the central and southern coast, and June to August in the north.
• Crocodile Bay, in the south, reports good blue marlin numbers in November and December.

Put together, about May to September plus November and December gives you the best odds. See the season chart for a month-by-month view.

How crews fish for them

Most boats troll large artificial lures in a spread at a steady speed, covering water until a marlin shows. Some crews switch to live bait, often a small tuna (bonito) caught on the way out, when they find fish around a school of tuna or a seamount. When natural bait is used, Costa Rican rules require circle hooks.

Tackle is heavier than for sailfish, usually 50 to 80 lb class gear on bigger boats with a fighting chair or harness. A sailfish rig can hook a marlin by surprise, and those fights tend to be long. If marlin are your main goal, book a boat that targets them on purpose and plan for a full day, since the best grounds can be a long run out.

The rules

Ley 8436 (article 76) declares blue, black and striped marlin species of tourist and sport-fishing interest. The fisheries regulation (Decreto 36782, article 68) says large pelagic fish are fished on a catch-and-release basis in sport fishing, with circle hooks when natural bait is used, and bans the sale of sport catches. INCOPESCA's agreement AJDIP/280-2014 bans placing billfish on the gunwale for photos and using gaffs or hooks to bring them alongside, except for world-record or approved-tournament fish.

So the marlin stays in the water while the crew removes the hook or cuts the leader, and the boat idles forward to push water through its gills before release. Every angler and crew member also needs an INCOPESCA sport fishing licence (Ley 8436, article 75), which many operators can arrange.

Eating quality

Marlin meat is sold in Costa Rica from commercial catches, but sport-caught marlin are released. Marlin is also on the US Food and Drug Administration's list of fish to avoid for pregnant women and young children because of mercury.