In the late 1980’s a few exotic lionfish were found off the coast of Dania Florida. I do not think anyone foresaw the impact this was going to have. Producing tens of thousands of drifting eggs per female each week, they began to disperse following the Gulf Stream. First in northeast Florida, then the Carolina’s, Bermuda, the Caribbean, and eventually the Gulf of Mexico. The invasion was one of the more dramatic ones seen in nature.
The Invasive Lionfish
Lionfish are found on a variety of structures, both natural and artificial, and are known from shallow estuaries to depths of 1000 feet in the ocean. They are opportunistic feeders, engulfing whatever is within their range and fits in their mouths, and have few predators due to their neurotoxicity spines. These fish are well-designed eating machines with a high reproductive rate, and perfectly adapted to invading new territories, if they can get there.
And they got here…
Like so many other invasive species, humans brought them to our state. Some arrive intentionally, some by accident, but we brought them. Lionfish came to Florida intentionally as an aquarium fish. Beautiful and exotic, they are popular at both public aquariums and with hobbyists… Then they escaped.
So what now?
What impact will these opportunistic fish have on the local environment? On the local economy?
This is, in essence, the definition of an invasive species. The potential for a negative impact on either the ecosystem or local fishing is there. We now know they are found on many local reefs, in many cases the dominant fish in the community. We know they can produce an average of 25,000 fertilized per female per week and breed most of the year. We also know they consume a variety of reef fish, about 70 species have been reported from their stomachs.
Over 70 species of small reef fish have been found in the stomachs of lionfish; including red snapper. Photo: Bryan Clark
However, what impact is this having on local fisheries?
Well, we do know there have been more reports of fishermen catching them on hook and line. We also know that scientists are examining the DNA of their stomach content that cannot be identified visually, and some of the results indicate commercially valuable species are on the menu.
Area high school students are now conducting dissections using this same methodology. Under the direction of Dr. Jeff Eble, over 900 area high school students examined the stomach contents of local lionfish last year. Students from Escambia, Gulf Breeze, Navarre, Pensacola, Washington, and West Florida high schools – along with Woodlawn Middle School – identified 16 different species in lionfish stomachs. Of economic concern were snapper; 42% of the prey identified were Vermillion Snapper – 4% were Red Snapper.
Though the consumption of non-commercial species can affect the population of commercial ones, the direct consumption of commercial species is concerning. The commercial value of Vermillion Snapper landed in Escambia County in 2016 was about $800,000 (highest in the state).
This year two more high schools will participate in the dissection portion of this project; those being Tate and Pine Forest. These students need lionfish and we are seeking donations from local divers to help support this project. If interested in helping, please contact me at roc1@ufl.edu or (850) 475-5230.
References
Dahl, K.A. W.F. Patterson III. 2014. Habitat-Specific Density and Diet of Rapidly Expanding Invasive Red Lionfish (Pterois volitans), Populations in the Northern Gulf of Mexico. PLOS ONE. Vol 9 (8). Pp. 13.
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Japanese Climbing Fern can quickly cover natural vegetation. Spores and small plants can be potentially transported in pine straw. Climbing ferns are a problem for managed timber and home landscapes. Photo by L. Scott Jackson
Most coastal residents along the panhandle are aware of the invasive lionfish and the potential impacts they could have on local fisheries and ecosystems. Since they were first detected in this area in 2010, there have been tournaments, workshops, and presentations, to help locals both learn about the animal and ways to control them. Existing non-profits have joined the fight and new non-profits have formed. In 2015 FWC and local organizations began hosting the Lionfish Removal and Awareness Day(LRAD) events. These are held the weekend after Mother’s Day. During the 2016 event in Pensacola, 8,089 lionfish were removed. In 2016 FWC introduced the Lionfish Challenge. This program began at the conclusion of the LRAD event and ran through September 30. Lionfish, or lionfish tails for those who wanted to keep the animal, could be turned into local collection sights and submitted for state awards and recognition – a Hall of Fame was created and King Lionfish. Over 16,000 lionfish were logged during this event. But has any of this helped? Are we getting control of this invasive species?
The Invasive Lionfish
Maybe… having conversations with local divers who work with researchers and remove for profit, it appears that the 2016 Pensacola LRAD may have made an impact. If you review the literature it states that to control an invasive species a minimum of 25% of the population should be removed annually. Others say you need to remove 75% and others still say it should be 25% each month. The problem here is that we do not know how many lionfish are actually out there. We know how many we are bringing in but is it enough?
One report, submitted by the non-profit REEF (from Key Largo) a few years ago, indicated they had removed about 70% of the lionfish in their area during one tournament. Based on this, the argument that tournaments are effective was supported. The recent Pensacola LRAD suggest the same. Local divers who remove lionfish with researchers, tourists, and as a commercial venture for themselves told us that their “sweet spots” – where high numbers of lionfish can be found – are not so sweet anymore. They are finding lionfish, but prior to LRAD it was not uncommon for some locations to have 50-100 lionfish around them. These same locations may yield 10-20 now. Though this information is anecdotal; it does suggest that these intensive tournaments may be having an effect on managing them. Of course a quantitative study is needed to confirm these observations, but it is encouraging none the less.
It is believed the tournaments alone will not solve the problem. With their high reproductive rates, continuous removals are needed. To encourage this divers can obtain a Saltwater Products Licensefrom FWC and sell what they catch. Some dive charters are now making it a tourism trip – “lionfish hunting”. As long as it marketed properly (as in they are not going to find tons of them – but will enjoy shooting a few) customers seem to be happy and are enjoying it. Of course they are still working on an effective trap so that non-divers can participate in control programs. It is also important to note that you should not get into a commercial venture on lionfish as your main source of income. To do so would lead to the argument “we do not want to get rid of lionfish because they are my livelihood”. The objective is to make them uncommon and reduce their impact on our marine resources.
Of course it will take time to know for sure just how effective the tournaments have been. Several will be meeting this week in Ocala to discuss the 2017 tournament season. I have written a longer update on the lionfish, which can be found at the Escambia County Extension Marine Science page.
The Asian Tiger Shrimp (Penaeusmonodon) have been reported across the northern Gulf of Mexico for several years now but unlike Cogon grass, Chinese tallow, and Lionfish they have not really made the press. We know they are there, but captures in shrimp trawls seem to be infrequent… it just does not look like a serious problem.
The Asian Tiger Shrimp can reach lengths of 12″
But now there is a study being conducted by Dr. Jennifer Hill (Louisiana Tech University) that sheds a little light on the impacts of this new invasive species. Working out of Dauphin Island Sea Lab, and funded by Mississippi-Alabama Sea Grant, her study is looking at the interactions between the tiger shrimp and our native species – the white and brown shrimp.
Tiger Shrimp as Predators
Dr. Hill has discovered that tiger shrimp do not prefer salt marshes, as our native species do. They are apparently too large, ranging between 8 and 10 inches – some as large as 14 inches, and prefer more open environments. Tiger shrimp may prefer seagrass beds, another haunt for local shrimp, but she is not sure at the moment. She has noticed that when tiger shrimp are around the native shrimp move towards structure. This is to avoid predation by tiger shrimp, which do try and catch them – but they are not very good at it. Her study indicates that 80-90% of the native shrimp survive such attacks, but forcing the natives towards structure could impact the catch by our shrimpers.
Tiger Shrimp as Prey
Preferring open environments leaves tiger shrimp at a higher risk of predation. One thought is that their large size and dark color may not be recognized as a shrimp by local predators. One species that has shown interest in them are redfish. Dr. Hill has found that redfish will not hesitate to go after them, and may actually prefer them over white shrimp, but – because of the size of the tiger shrimp – it must be a large redfish.
Five tiger shrimp captured by shrimpers in Pensacola Bay.
Shrimpers in Alabama and Mississippi are currently selling the tiger shrimp they capture to Dr. Hill for her studies. She found that very few were captured in 2014, possibly due to the cold winter that year, but had plenty submitted in 2015. The mild winter of 2016 may produce a large number this summer. If you are shrimper in the Pensacola area, and interested in selling live tiger shrimp at $30 each, contact Dr. Hill at (251) 861-2141 ext. 2179.
Five tiger shrimp captured by shrimpers in Pensacola Bay.
Giant Tiger Prawn (Penaeus monodon):
This catchy phrase coined by Robert Turpin (Escambia County Marine Resources Division) describes a recent invader to our marine waters in the past decade. Many coastal residents are aware of the invasive lionfish that has invaded our local reefs but less have probably heard of the Asian Tiger Shrimp. This member of the penaeid shrimp family, the same family are ediblewhite, brown, and pink shrimp come from, was brought to the United States in the 1960’s and 70’s as an aquaculture project. Over the years farmers have moved from Tiger Shrimp to the Pacific White Shrimp and the last known active farm was in 2004.
The Asian Tiger Shrimp can reach lengths of 12″
In 1988, two thousand of these shrimp were lost from a farm in South Carolina during a flood event. Only 10% of those were recaptured and some were collected as far away as Cape Canaveral. No more was heard from this release until 2006 when 6 were captured; one of those in Mississippi Sound near Dauphin Island. Each year since the number of reported captures has increased suggesting they are breeding.
In the Panhandle, one individual was caught in 2011 near Panama City and 5 were collected in 2012 in Pensacola Bay. They have been found in all Gulf coast states and there has been at least 1 record in each of the Florida Panhandle counties. The future impact of this shrimp to our area is still unknown but they have a high tolerance for salinity change and consume many types of benthic invertebrates. Tiger shrimp may out compete our native penaeid shrimps and could possibly feed directly on the juveniles. It is thought that they could possibly transmit diseases to our native shrimp.
Giant Tiger Prawn: This large shrimp, also known as the Asian Tiger Shrimp and the Black Tiger Shrimp, can reach lengths between 8-12 inches. It resembles are native edible penaeid shrimp but differs in that it has distinct black and yellow stripes.
NOAA scientists are interested in obtaining samples of this shrimp for DNA studies. It differs from other local penaid shrimp in that it is larger (8-12” long), dark in color (dark green to black) and has light stripes (white to cream colored). The larva and juveniles live in the bay. Sub adults will migrate offshore for breeding. They are a tropical species that have a low tolerance for cold temperatures, showing no growth below 20°C. If you think you have found one of these shrimp, record size location (GPS preferred), and email information to ExoticReports@MyFWC.com. You can also report to EDDMapS using the website or I’ve Got One! phone app. To learn more about Tiger Prawns view the USGS factsheet.
The nonnative Giant Tiger Prawn – also known as the Black Tiger Shrimp. Photo by David Knott, Bugwood.org
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