SEA SCIENCE: Hooks in the Gulf Stream: Captains and Scientists Reel in Data

Fishing aficionados are constantly discussing the best baits, lines, leaders and hooks to improve their fish-catching odds.

For instance, a current saltwater equipment-related discussion in North Carolina’s multimillion-dollar, deepwater charter boat industry swirls around which of two types of fishing hooks — “J” or “circle” — can best hook, hold and land certain open-ocean species popular as seafood.

Numerous published studies conclude that circle hooks can significantly reduce the number of fish killed in catch-and-release billfish fishing because the hook’s design prevents deep hooking by helping it slide to the fish’s jaw or mouth corner, not its gut or throat.

However, the bulk of the catch in deepwater recreational fishing is harvested, not released.

A recent N.C. Fishery Resource Grant Program study focused on the catch rates of the three finfish species most often targeted by charter boats in federal waters: dolphinfish, also known as mahi-mahi; yellowfin tuna; and wahoo. Researchers wondered if circle hooks would maintain catch rates for these species. North Carolina Sea Grant administers the FRG Program, funded by the N.C. General Assembly.

The research excluded billfish — swordfish, marlin, spearfish and sailfish — which are recreational catch-and-release tournament favorites.

“There is a fear that the National Marine Fisheries Service, which already requires natural baits to be rigged with circle hooks in billfish tournaments, has a goal that will require nothing but circle hooks to be used by all fishermen in the future,” explains Dale Britt, a charter boat captain, and part of the research team.

“Whether on a charter boat or on his own 25-foot Parker, every fisherman wants to catch fish to take home and feed his family,” he adds. “Using a circle hook requires a whole new learning curve. With J hooks, his chances of catching fish to take home are a whole lot better.”

GATHERING DATA

Paul Rudershausen, on staff at North Carolina State University’s Center for Marine Sciences and Technology in Morehead City, collected hook efficacy data with a team that included other scientists, and charter boat captains and their mates. The results would then be given to captains and fishery regulators faced with making decisions.

“Circle hooks may be considered for all offshore troll fishing off the U.S. Atlantic coast because meatfish, especially dolphinfish, yellowfin tuna and wahoo, often are found swimming and interacting with billfish,” Rudershausen says.

“There is concern in the charter boat industry that circle-hook regulations developed for and based on billfish, if ever mandated outside of U.S. Atlantic billfish tournaments, would negatively impact catch rates of nonbillfish species and customer satisfaction,” he continues.

No such rule now exists for charter boats, but having already seen circle-hook regulations enforced in commercial and tournament scenarios, charter captains remain wary, Rudershausen adds.

The federal Magnuson-Stevens Act requires NMFS, when practical, to minimize bycatch and bycatch mortality in the open ocean, defined as more than three miles offshore.

Since 2004, NMFS has required commercial vessels using open-ocean,longline gear in Atlantic highly migratory species — or HMS — fisheries to employ only circle hooks. The NMFS website notes “tremendous conservation benefits for sea turtles since the majority of sea turtle mortalities in longline fisheries are caused by ingestion of ‘J’ hooks.”

A 2008 NMFS regulation requires recreational fishermen on HMS -permitted vessels to use circle hooks with natural baits or natural bait-artificial lure combinations when fishing in Atlantic coastal billfish tournaments.

As hook debates continued, Rudershausen and Jeffrey Buckel, a biologist on CMAST faculty, convened a workshop for charter boat industry members, scientists and fisheries managers to discuss gear types and fishing methods to compare the circle and J hooks in other fisheries.

Two veteran charter captains, Britt and Pete Zook, then joined the team that sought and received FRG funding to look at the performance of the two hook types in North Carolina’s wahoo, yellowfin tuna and dolphinfish troll fishery. The team also used a CMAST research vessel as a simulated recreational craft to collect data.

For each species, researchers compared circle and J hooks simultaneously, fished side-by-side, on a total of 75 trips by the charter and simulated recreational anglers.

The team also included Gregory Bolton and Tyler Averett of CMAST; Randy Gregory of the N.C. Division of Marine Fisheries; and Paul Conn of NMFS.

CATCH LINGO

Researchers used the following terms: A strike happens when a fish interacts with gear so the line is pulled out of the outrigger clip. Outriggers allow more lines in the water at once.

In a hook-up, a fish is hooked for more than 10 seconds after striking.

A fish is caught when an angler pulls the leader to bring the fish close enough to be gaffed or when the fish is boated.

Using ballyhoo rigged with either circle and/or J hooks, the team members attached leader types typically fished for each species: monofilament for dolphinfish, fluorocarbon for yellowfin tuna and wire for wahoo.

They compared numbers of strikes, hook-ups and proportions retained, and numbers of fish caught. The team also recorded hook location, including deep hooking.

The study’s results indicated no difference in the number of strikes between baits rigged with J or circle hooks.

Also, once the fish was hooked, both types of hooks were equally successful in landing it.

However, the big difference was the number of fish: J hooks hooked — and landed — more fish. And landing is what it’s all about for those who prefer meat fish.

WHAT THE HOOK

“The problem is how the fish interact with the baited hook — swiping at the bait, or trying to swallow it whole — and what the angler does in response,” explains Marc Turano, Sea Grant mariculture specialist who also reviews FRG projects.

“If a fish strikes at a bait,” he says, “but does not hook up, the bait is often dropped back to get the fish to hook up. But that could lead to the fish swallowing the hook. This is where circle hooks work well.”

Britt concurs. “You need to size your tackle according to the fish,” he notes. “Certain fish are impact strikers — they crash the bait. Whereas others will paddle up behind the bait and take it. If you’re targeting white marlin or sailfish, the circle hook is effective.”

Brian Efland, Sea Grant coastal resource specialist, agrees that wahoo, dolphinfish and tuna all strike trolled baits differently. “The techniques employed for circle-hook billfishing during tournaments can produce high hook-up ratios, but may not be as successful for various meatfish species during daily charter operations,” he says.

For instance, in tournament catch-and-release fishing, an experienced crew trolls slowly, uses a light outrigger clip setting and drops the baited line back towards the fish when it strikes.

“This technique may not be practical for everyday charter trips where the ultimate objective is to harvest fish for a charter party, often comprised of novice anglers and one mate in the cockpit,” Efland explains.

Rudershausen maintains, with qualifications, that “circle hooks are not as effective as J hooks in the dead-bait troll fishery for dolphinfish, yellowfin tuna and wahoo off the coast of North Carolina.” However, as he notes, the fishing tackle industry and charter boat operators continually adapt gear and techniques to increase catch efficiency.

“There are likely untested techniques that allow fishers to catch non-billfish with circle hooks more efficiently than we found in this study, such as other circle hook sizes that may have been more effective than the sizes we tested,” he adds.

For more information, visit the following websites:

• Full study report: www.ncseagrant.org and search for 10-FEG-06

• NOAA bycatch regulations: www.nmfs.noaa.gov/sfa/hms/ahms.htm

• Circle-hook tournaments: Go to: portal.ncdenr.org/web/mf/ and follow links for Recreational Fishing and then Fishing Tournaments

This article was published in the Winter 2012 issue of Coastwatch.

For contact information and reprint requests, visit ncseagrant.ncsu.edu/coastwatch/contact/.