2018-06-01 / Features

ALIEN INVADERS IN OUR LOCAL WATERWAYS

By Robert Turpin


Robert Turpin Robert Turpin My usual articles focus on native species inhabiting local waterways; however, this month’s marine creature feature is the lionfish. Lionfish is the common name given to any of approximately two dozen species of fish that are native to the

Indo-Pacific region. Lionfish are popular aquarium fish because of their body coloration and ornate fins. Our best estimation of the source of the lionfish invasion is that a few lionfish were released into the Atlantic Ocean in the mid- 1980s. Genetic analysis of fin-clips from lionfish collected in the ensuing years of the invasion indicates as few as 20 female lionfish were the maternal source of the millions, perhaps billions, of lionfish now inhabiting the entire Gulf of Mexico, Caribbean Sea and western Atlantic Ocean from Venezuela LIO N FIS H to New York. An internet search of “USGS animated lionfish invasion” will yield a time-sequenced graphic animation showing the expansion of lionfish sightings in the years since 1985.

Because lionfish are not native to the invaded range, our marine ecosystems have no native predators, diseases or other ecological control to lionfish population. As a result, lionfish are larger and more numerous in the invaded range.

The largest lionfish captured in the waters off Florida exceeded 18 inches in length. Lionfish can consume prey species measuring over one-third their body length, and most native fishes do not recognize lionfish as predators -- until it is too late.

I collected a 12.75-inch lionfish off a local artificial reef and found 26 vermilion (aka “mingo”) snapper in its stomach. Lionfish apparently eat beyond satiation and store large deposits of fat in their gut cavities.

Lionfish possess 18 venomous spines, capable of inflicting painful stings. These spines are located in the dorsal and ventral fins, and they are extremely sharp. I have been stung in the finger and can only describe the pain as a combination of wasp stings and being hit with a hammer. Careful application of heat will denature the proteinbased venom, but medical care may be necessary if spines are broken off in the wound or if secondary infection or other issues arise.

Lionfish reach sexual maturity in their first year of life and spawn prolifically. Each female lionfish can produce up to 30,000 eggs per spawning event -- every few days. The eggs and planktonic larvae broadcast each new generation of lionfish over wide areas. Juvenile lionfish settle to natural and artificial reefs, and they can also tolerate low salinities inside estuaries.

I collected the first lionfish from the waters off Pensacola in 2010 while inspecting artificial reefs for impact of submerged oil from the Deepwater Horizon oil spill. Over the following eight years, local divers have observed and speared tens of thousands of lionfish from our reefs. Although lionfish are sometimes caught on hook-andline, divers with spears are the most effective means of removal, at present. Due to divers’ limitations in depth and bottom-time, more efficient means of lionfish harvest are being researched.

Until traps or other lionfish removal devices are perfected, divers are our only lionfish removal alternative. A silver lining to the dark cloud of the lionfish invasion is that they are excellent table fare.

Lionfish have a mild flavor, very similar to flounder.

Lionfish venom (not poison) is located only around the spines; therefore, the flesh is safe to eat if handled carefully, as with other seafood. The harvest of lionfish for seafood markets and restaurants has great potential to incentivize large-scale and sustained lionfish removal from the invaded range.

Lionfish are also being included as eligible species in local fishing rodeos. Recently, Florida’s fourth annual Lionfish Removal & Awareness Day event was combined with a Lionfish World Championship Spearfishing

Tournament. Ninety-nine divers removed over 9,000 lionfish from the Gulf of Mexico waters off Alabama and the Florida Panhandle.

A new lionfish spearfishing rodeo, Spearo 4 AHERO, was scheduled to be held in conjunction with the Fishing 4 AHERO fishing rodeo Memorial Day weekend 2018.

Florida Fish and Wildlife Conservation Commission has created the 2018 Lionfish Challenge from May 19-Sept. 3, with great prizes for lionfish hunters. Dozens of lionfish have been tagged at local public artificial reefs, and those tagged fish are worth big cash prizes. See www.MyFWC.com for registration and additional information.

These events stimulate lionfish harvest and help increase public awareness of the lionfish invasion. Although we will never totally eradicate lionfish from the invaded range, perhaps we can eat our way out of the complete domination of our marine ecosystems by lionfish. Non-divers can also be part of the solution by asking for lionfish at a favorite grocery store, seafood market or restaurant.

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