Off the coast of Louisiana lie some of the world's most productive and unusual reefs. Not the coral or shell types that most people think about when "reefs" are mentioned, but the steel-legged kind that oil production companies plant throughout the waters of the If of Mexico. No doubt the early engineers of these structures gave little thought at the time of their development as to the positive impact such installations would have on marine life and the fishing community.

"Whether an operating oil and gas production platform or a retired platform intentionally placed for conservation and fisheries enhancement, a typical four-pile platform jacket (the underwater support structure of an offshore platform) provides two to three acres of living and feeding habitat for thousands of underwater species," according to the U.S. Department of the Interior, Mineral Management Service (MMS).

It is no wonder that many anglers are finding that these steel offshore oil production platforms draw fish like magnets. Besides harboring numerous juvenile and adult resident species, these steel-legged reefs serve as hunting grounds for swift, open-ocean pelagic fish like mackerel, tuna and jacks.
   
Marine researchers have reported fish densities 20 to 50 times higher at oil and gas platforms than in nearby open water, and each platform seasonally serves as critical habitat for 10,000 to 20,000 fishes, many of which are of recreational and commercial importance.

One man that knows well the fish-attracting power of offshore platforms is Captain Scott Avanzino of Paradise Charters out of Venice, La. He's honed the technique of catching tuna at night down to a science.
While oil-production platforms attract fish 24 hours a day, the odds of catching them increase by night due to the lighting on many of the rigs. For example, bright vapor lights often beam down to the water's surface on these structures, over­shooting bridge walks, loading docks and other areas requiring illumination. "The lights of the rigs simply attract bait," Avanzino said, "and the structure which doubles as a full-time fish attracting device, coupled with the lights, serves as a nighttime beacon marking a presumed safe haven for bait fish for miles."

Avanzino particularly likes fishing deep­water platforms that are generally found throughout the blue water zone of the Gulf of Mexico. He's found that tuna have adapted to feeding under the lights not just to satisfy their constant urge to eat but because it is easy pickings.

The oil-production platforms provide an excellent setting for tuna to ambush bait fish. Here they use the cover of darkness to lie in wait for unsuspecting bait to come into their forage areas. For the yellowfin tuna, this forage area lies on the outer reaches of the up current side of the platform near the surface (0 to 50 feet) where the rig light fades into natural darkness (100 to 400 yards). On the other hand, blackfin tuna prefer depths closest to the rig (50 to 100 yards) where the last reaches of penetrable surface light fade into complete darkness (100 to 200 feet).

Tuna can be found at just about any lighted rig in 300 or more feet of water. This is particularly true of blackfin tuna, while yellowfin tuna prefer deeper blue water where temperatures range between 68 and 84 degrees. These are ideal areas that draw flying fish, the preferred diet of yellowfin tuna.

Blackfin and yellowfin tuna also prefer to feed on different baits. Blackfin favor squid and yellowfin favor flying fish. To be successful, you have to employ baits and methods that imitate the specific bait for each species. Heavy chrome jigs, like the diamond jigs, imitate squid, while surface baits, like top-water poppers, imitate injured flying fish.

Blackfins are more interested in chasing squid at depths the light becomes less of a factor. Bearing this out is the fact that Avanzino has caught blackfin as far as a mile away from a rig where there was no penetrable surface light at all. The only evidence that they were there came via the fish finder display.

Avanzino believes that fishing the up current side of a rig is far better than the down current side. His reasoning is that there is always more surface activity and a fresh supply of flying fish and flotsam. One effective method that he uses is drifting with the grass patches toward the rig, looking for the flying fish to get flushed out of hiding. When this occurs, he casts his bait right in front of them.

Blackfins are usually easy to catch at night, so easy at times anglers can virtually sink the boat with them. They will hit anything that is moving fast on the drop or rise.

For the sheer fun and challenge, most anglers choose to use light tackle. The four-to-six ounce diamond jig in chrome or glow color is the weapon of choice. Avanzino uses 30-pound line or lighter with a medium rod in an attempt to match the tackle.

Blackfin are most often found 50 to 200 feet down and close to the rig structure where they enjoy feeding on squid. At night they come to the surface. That's why diamond jigs work so effectively; they mimic tiny squid.
  
Though many tuna anglers think you have to jig the lure up and down briskly for a strike, this really is not necessary. It just has to be moving fast in one direction or the other— up or down. It is as simple as dropping the lure 200 feet down and then reeling it in quickly.
   
Comparably speaking, yellowfin tuna are harder to catch than blackfin. To be successful, it is important to catch some live bait. Hardtail jacks are a good choice but they can be difficult to catch at night. The best choice, according to Avanzino, is fly­ing fish, either dead or live.

Most of the time a spreader light and cast net are all that's needed, but a fisherman's green light will work wonders if you can find a safe way to hang it off the transom. Once the flying fish swim up to the light, all you need to do is throw a cast net to catch them.

In any case, if there's a problem with catching flying fish, the next best alternative is to use top-water poppers. Once again, the action is more important than color choice. This lure is basically designed to spit water from its cupped head as it moves forward. Thus the trick is to get the lure to dart through the water sporadically with a sweeping action.

"I have seen tuna follow the bait all the way to the boat and hit it at the very last second," Avanzino said. "If the yellowfins are not actively feeding, try making blind casts at or near patches of scattered grass. Odds are that the tuna are not too far below." Sometimes yellowfin can be observed boiling the water's surface in a feeding frenzy. When this situation is encountered, cast the bait anywhere near them and a successful hookup is imminent. If they happen to be out of casting range, then be sure to move stealthily. Never make a bold run into or near feeding fish as this will cause them to disperse and go deep.

Gear selection is most critical when going after these torpedolike speedsters. Avanzino uses Alutecno Albacore 50/80 reels with 650 yards of 80-pound monofila­ment for yellowfins because the drags are smooth, precise and dependable. It is impossible to put the drag in free spool or full strike without pressing a button on the side of the reel, so there are no birdnests on the take or during the fight and no spastic two-thumb break offs due to accidental over-drag once the drag has been set.

Proper drag setting is as equally essential as the right equipment. The reels are set with 27 pounds of fight drag, leaving the strike drag at about two to three pounds on the take. When a tuna grabs the bait, it is crucial to let him run for a second or two and slide the lever up to full position while reeling. When properly executed, it plants the 12/0 circle hook in the side of the mouth every time. When fishing live bait, Avanzino hooks the bait in the mouth from the bottom lip through the nostril with a Mustad 8/0 live bait hook attached to 20 feet of 130-pound fluorocarbon leader attached with a dacron loop to a bimini twist on the main line.

Though details to the specifics may vary among anglers, one thing's for sure— the fish will be there waiting at Louisiana 's steel-legged reefs.