Trawling for Answers: Study Examines Bycatch Rates in Southeastern North Carolina

Denny McCuiston lives in North Carolina and trawls for shrimp in North Carolina — his 24-foot Diamond boat, “DrawPlay” was even built in North Carolina.

“There’s not many people left like me,” says McCuiston, a WrightsviUe Beach resident. For more than 30 years, he has trawled the inside waters of the state’s southeastern coast.

But some area residents and policymakers believe trawling in the region’s narrow waterways unintentionally captures and kills large amounts of commercially valuable fish and invertebrates, known as “bycatch.”

In March, an N.C. Division of Marine Fisheries (DMF) meeting in Bolivia to discuss the possibility of closing areas of Brunswick County to shrimping was packed with concerned shrimpers and area residents.

“The concerns with inshore shrimping mostly have to do with commercially and recreationally valuable finfish, primarily croaker, spot, gray trout — such as weakfish — and flounder,” says Elaine Logothetis, a biologist from Wilmington.

Some fear that if large numbers of these species end up as bycatch, their populations will decline and hurt the state’s other fisheries, she explains.

In 2004, Logothetis and McCuiston received an N.C. Fishery Resource Grant (FRG) to assess the bycatch generated in the state’s southeastern shrimp fisheries. The FRG program is funded by the North Carolina General Assembly and administered by North Carolina Sea Grant.

Logothetis designed the project to examine bycatch generated by the trawling patterns of an actual commercial shrimper — in this case, McCuiston.

“Bycatch is the issue in the shrimp industry,” he says,

The issue made headlines in 2003 when state Rep. Bonner Stiller, a Republican from Brunswick County, introduced legislation to ban all shrimp trawling in the Intracoastal Waterway (ICW) in Brunswick and New Hanover counties. A contentious public debate erupted, revealing a lack of scientific data on area bycatch.

“There has always been a question as to the magnitude of the bycatch generated by small commercial operations in the southern parts of the state,” notes Rich Carpenter, DMF Southern District manager.

The bill eventually was withdrawn, but the controversy continued to simmer, prompting the DMF to speed up development of a statewide Shrimp Fishery Management Plan.

Data from Logothetis and McCuiston’s research has proved invaluable to the plan’s development, adds Scott Baker, a Sea Grant fisheries specialist based in Wilmington.

“Until this study, we had to refer to studies in other areas that may or may not have been applicable to these situations,” observes Baker.

EXAMINING THE QUESTION

Although McCuiston is a commercial shrimper, Logothetis is quick to point out they aren’t taking sides. “We are here to examine the question: What is the bycatch?”

From April through November 2004, Logothetis accompanied McCuiston twice a week as he trawled in areas from the New River to the South Carolina border, including Onslow, Fender, New Hanover and Brunswick counties and the Cape Fear River.

McCuiston didn’t trawl in all of these areas throughout the entire season, partly due to restrictions. DMF closed different areas at different times to let juvenile shrimp and finfish develop. But sometimes McCuiston avoided certain areas simply because there weren’t any shrimp.

“We were trying to mimic what typical shrimpers would do — they are not going to be in a place where there are no shrimp,” says Logothetis.

McCuiston trawls for pink shrimp (Peneaus duoranmi) in the spring, brown shrimp (Peneaus aztecas) in the summer and white shrimp (Peneaus setifems) in the fall. He uses a single rig otter trawl — a long, cone-shaped net with a wide-open mouth at the front that tapers to a closed end or “tailbag.”

The trawl is dragged behind the boat, and a chain near its mouth stirs up the bottom. Two large, heavy, flat wooden panels, or “doors,” on either side of the net hold it under water and keep the mouth open. McCuiston’s net also is fitted with a turtle excluder device (TED) and bycatch reduction device (BRD), as required by law.

For each tow, Logothetis recorded their location using a Global Positioning System (GPS) unit, as well as water salinity, temperature, depth and tide phase.

After hauling in the nets, McCuiston and Logothetis separated the shrimp from the bycatch, and Logothetis weighed all of the shrimp and measured a subsample to record their size. She then grouped the bycatch according to species, weighed each group, and measured the lengths of individuals from different subsamples.

“We looked at the total weight of the shrimp compared to that of the bycatch and then further categorized the bycatch based on dominant species,” explains Logothetis.

Of the top 10 bycatch species determined by weight, five were commercially or recreationally important species: blue crab, Atlantic croaker, gray trout, spot and summer flounder.

In addition to catch ratios, Logothetis determined the catch per unit effort (CPUE) for shrimp and bycatch. CPUE is the weight of a species caught over a unit of time, such as two kilograms of shrimp per 30 minutes.

Overall, Logothetis concluded the catch ratio and CPUE for shrimp were higher than for bycatch.

But she also found that more bycatch was caught in the spring, during the pink and early brown shrimp seasons.

“The beginning and end of shrimp seasons are when shrimpers are most likely to catch a lot of finfish bycatch,” says McCuiston. “The shrimp just are not as abundant then,” adds Logothetis.

By looking at the shrimp and bycatch separately, she and McCuiston found the catch rates for bycatch were fairly similar across all the months of the project. But shrimp catch rates increased dramatically in July, she notes.

“This is important because it shows that the quantity of bycatch itself changes little during the shrimp season…by contrast, the quantity of the shrimp changes significantly,” says Logothetis.

“When the shrimp are abundant, generally the catch is more shrimp than bycatch.”

MANAGING THE RESOURCE

Most states prohibit trawling in estuarine, or inside, waters. But North Carolina’s distinctive coastline makes the state an exception.

At the northern end, the wide waters of the Pamlico and Albemarle sounds stretch nearly 100 miles from north to south and — in some places — more than 25 miles from east to west. Shrimp catch here is plentiful, averaging 50 percent of the state’s total shrimp landings between 1999 and 2003, according to DMF records. Only about a quarter of total landings were from the Atlantic Ocean.

But south of Onslow County, inside waters are much narrower. Some areas stretch only a few hundred feet across in New Hanover and Brunswick counties. The shrimp catch in southeastern inside waters is limited, averaging slightly more than 7 percent of North Carolina’s total shrimp landings between 1999 and 2003.

Although trawling is legal in inside waters, it is not without restrictions. Shrimping is prohibited in the state’s primary nursery areas, the shallow, low-salinity waters in the upper portions of creeks and bays that are sources of food and shelter for juvenile fish and shellfish.

As juveniles develop, they eventually move into lower portion of the creeks and bays, designated as secondary nursery areas. Trawling also is prohibited here. Areas adjacent to secondary nurseries are classified as “special secondary nursery areas.”

“They only let us shrimp there a very small part of the time,” says McCuiston of the special secondary areas. “And when they do, they wait until the shrimp are a certain size.”

Currently, DMF manages shrimp catches based on count size. If 20 shrimp equal a pound, then the shrimp are fairly large. If 100 shrimp equal a pound, the shrimp are small, and DMF will close certain areas to trawling.

In Pender County, most of the inside waters are managed as special secondary nursery areas. As part of developing the Shrimp Fishery Management Plan, DMF recommended designating more of these areas in New Hanover and Brunswick counties.

Logothetis’ findings on count size supported some of DMF’s long-term data on shrimp in New Hanover County: mainly they’re not very big.

There is not much viable habitat left along the county’s heavily populated, 20-mile stretch of the ICW, she says. “The shrimp get washed out into the Intracoastal Waterway and never really become a marketable size.”

In the draft of the Shrimp Fishery Management Plan presented to the Shrimp Advisory Committee — a panel of various interests helping to develop the plan — DMF recommended trawling be prohibited in the ICW from Rich Inlet to Wrightsville Beach Bridge.

That didn’t cause too much protest, says McCuiston, who sits on the committee. The majority of shrimping in New Hanover takes place further south near William’s Landing, he explains, in an area between Wrightsville and Carolina beaches.

In 2003, only 10 small commercial shrimpers trawled in the William’s Landing area, generating about 6,000 pounds of shrimp, according to DMF records. Since 1994, landings in the area have averaged only 4,000 pounds.

Logothetis and McCuiston discovered that the bycatch to shrimp ratio was only 0.7 pounds of bycatch for every pound of shrimp at William’s Landing, the second lowest catch ratio among all of their study areas.

The DMF also recommended designating part of William’s Landing — from channel markers 139 to 146 — as a special secondary nursery area. Given the small fishing effort, the Shrimp Advisory Committee supported the option.

The committee was less willing to compromise for Brunswick County, however. Panel members decided sporadic availability was better than no availability.

The DMF recommendation was to prohibit shrimp trawling in the Eastern Channel, Shallotte River and the ICW from the Sunset Beach Bridge to South Carolina, and near the Lower Calabash River.

Currently, the DMF only opens these areas when shrimp reach harvestable size. But different shrimp species develop at different times. Sometimes they are ahead — or behind — schedule.

“Prior to brown shrimp reaching a harvestable size, you may have smaller white shrimp drop in,” explains Carpenter.

These smaller shrimp interfere with the count size, and the DMF closes the area. Lengthy closures of Brunswick County waters last year meant Logothetis and McCuiston collected a limited amount of bycatch data in that area.

They determined about 1.5 pounds of bycatch was generated per pound of shrimp, but nearly all of their trawling in Brunswick took place in May, the beginning of the season when shrimp are not as abundant. They also trawled a handful of times in late July and late August, when small or juvenile fish are most abundant.

“We don’t have a complete season to look at for Brunswick,” says Logothetis, noting they were only able to trawl in Brunswick once during the fall.

In addition to banning shrimping in the ICW in Brunswick and New Hanover counties, Rep. Stiller’s 2003 bycatch bill had called for a ban in the Cape Fear River. Later, the bill was rewritten to exclude the river because larger commercial vessels trawl there.

Besides, notes McCuistion: “We don’t catch enough there to justify closing the river based on the amount of bycatch.”

He and Logothetis documented the lowest bycatch to shrimp ratio in the Cape Fear River — only 0.38 pounds of bycatch for every pound of shrimp.

UNCERTAIN FISHERY, UNCERTAIN FUTURE

Managing a fishery as complex and geographically diverse as North Carolina’s shrimp fishery is difficult, but each session is a new challenge for those who trawl.

“I’ve done this for 33 years and no two years are the same,” says McCuiston. “Next year, there may be a ton of shrimp down in Brunswick County.”

He and Logothetis plan to find out — they were recently awarded another FRG grant to continue the bycatch study in 2005.

“If every year is different, you can’t base potentially permanent management decisions on one year’s worth of data,” says Logothetis.

One thing everyone is sure about is that shrimp seem to be getting smaller every year. For shrimpers, that means more DMF closures, fewer days trawling, and a less marketable product.

“There’s nothing wrong with small shrimp,” says Logothetis. “They taste the same, but people don’t want them.”

Some on the Shrimp Advisory Committee blame increased development along the ICW for smaller wild shrimp.

“If shrimp are forced to leave nursery areas because of pollution, they can’t grow to a marketable size,” says Henry Daniels, a shrimper from Belhaven, and member of the Shrimp Advisory Committee.

Although that may be true, bycatch remains a prominent issue for the state’s southeastern inside waters as the DMF develops its recommendations for the Shrimp Fishery Management Plan.

“The main portion of the plan is completed,” says Carpenter. “Now we are just addressing individual areas.”

The DMF expects to present the N.C. Marine Fisheries Commission with a draft of the management plan in June, adds Carpenter. From there, the commission will review the DMF recommendations, as well as any dissenting opinions put forth by the Shrimp Advisory Committee on individual issues such as access to areas in Brunswick County. Final decisions on such matters will rest with the commission.

“The division is trying to change management some, but they are taking little steps instead of big giant leaps,” observes McCuiston.

And little steps are often the easiest for all parties to take.

“It’s hard for the fishing community to vote for options that are going to take work away from them,” he adds.

This article was published in the Early Summer 2005 issue of Coastwatch.

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