Deep-release puts the pressure on rockfish survival

Take your pick: Whether homemade or a commercial design, every sport fishing boat in Southeast Alaska must have a deep-release mechanism on board beginning August 1. (Photo by Robert Woolsey/KCAW)

For sport anglers in Southeast Alaska having a slow day trying for salmon or halibut this August there will be no “plan B” for bottom-dwelling rockfish.

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The Alaska Department of Fish and Game is closing all sportfishing for nonpelagic rockfish in outside waters from Yakutat to Ketchikan for three weeks beginning Aug. 1, to conserve these long-lived, slow-growing species.

Those fishing inside waters will have a bag limit of one.

A favorite species of pelagic rockfish — called a black bass, or black bomber — is unaffected by the emergency order. The sport bag limit remains five fish per day.

This is about more than yelloweye, the large, bright orange rockfish that sometimes is called “snapper,” and sometimes saves an otherwise bad fishing trip.

The roster of nonpelagic rockfish sounds like the currency of an exotic country.

“Quillbacks are common. Coppers,” Troy Tydingco said. He’s the sportfish management biologist. “Then there are some small ones that are also common: rosethorns, canaries. I’ve seen some vermillions recently. There are some really interesting ones like the tiger, the China, the red-banded.”

And don’t forget silvergrays, bocaccios and harlequins.

Spread out before Tydingco is what appears to be a fairly menacing arsenal of tools to hook, pinch, clamp or otherwise catch fish.

But actually this is lifesaving equipment for rockfish.

“The idea with pretty much all of them is that you’re going to be able to get a rockfish back down at depth. Because rockfish have got that closed swim bladder, when you bring them up they’re subject to barotrauma,” Tydingco said. “You’ve probably seen where their stomach comes out, their eyes pop out. If you can get them down back quickly where they’re back under pressure, it reverses all those effects.”

Barotrauma is as deadly as it sounds.

Tydingco said only 20 percent of rockfish survive it. The distended swim bladder doesn’t allow them to return to the bottom, and they remain helpless on the surface, easy pickings for an eagle.

Biologist Troy Tydingco says rockfish can survive barotrauma if they’re promptly released at depth. “Get them back down quickly,” he says. (Photo by Robert Woolsey/KCAW)

On the other hand, 95 percent of the rockfish released with one of these devices live.

For three weeks, from Aug. 1 through 22, sport anglers in outside waters are going to have let all non-pelagic rockfish go — at 100 feet of depth.

Just as charter operators have been doing for several years, all fishermen are going to have to have a deep release mechanism with them on the boat.

It doesn’t have to be fancy — even though it can be.

Tydingco’s got one he’s made from an 8-inch piece of rebar, with a big fishing hook taped to it.

The barb on the hook has been pinched down.

“Usually the way I use this is that same hole that you catch the fish in, put the hook through there, and just send it down,” Tydingco said.

Tydingco ties 100 feet of line to his homemade release mechanism, and cleats it off to his boat.

When the rockfish is back under pressure, it recovers instantly, slides off the hook, and heads for the bottom.

Another commercial mechanism has a pressure-activated switch that allows users to choose a depth.

“Some people use these on their downrigger,” Tydingco said. “Send them down and they pop right open.”

There’s a video on the Fish & Game website showing how these things work underwater.

In addition to closing the coastal waters of Southeast Alaska to the retention of rockfish, the emergency order also limits sport anglers on inside waters around Ketchikan, Petersburg, Wrangell and Juneau to one nonpelagic rockfish.

But the effect is nearly the same: After that first fish, you’ll have to release all the others — also at a depth of 100 feet, if you’re aboard a charter boat.

This is the first time Fish and Game has closed the rockfish sport fishery — but it’s not out of concern that sport anglers have been catching too many.

According to data gathered in the statewide harvest survey, creel survey, and charter logbooks, the harvest has remained fairly constant, at about 16 percent of the Total Allowable Catch (or TAC) for nonpelagic rockfish.

Instead, it’s the TAC itself that’s dropping — from 66 metric tons in 2006, to 35 metric tons this year.

This is of concern. Rockfish don’t rebound the way some other species do. In fact, their lifespans our better than ours.

“They vary by species,” Tydingco said. “A big yelloweye, it’s not uncommon for them to exceed 100 years.”

Tydingco said they’re slow to reproduce.

Again, depending on the species, some rockfish don’t reach sexual maturity for at least 12 years.

Other than conserving stocks, there’s no biological objective behind the August closure.

“We could have chosen any three weeks,” Tydingco said. “We wanted to make sure there were plenty of coho around to target instead.”