In the western Atlantic Ocean the recent appearance of Pterois volitans, better known as the lionfish, indicates a marine invasion on a scale not seen before in the region. “The lionfish invasion in the northwestern Atlantic and the Caribbean represents one of the most rapid marine fin-fish invasions in history” (Morris, 2008). Caribbean coral reefs are already considered fragile ecosystems with an important role to play as juvenile fish nurseries, and as biodiversity hotspots. Synergistic pressures from habitat destruction, overfishing and pollution make the nascent addition of the invasive lionfish even more troubling.
A successful management response is needed quickly in order to prevent permanent habitat destruction and biodiversity loss. Some forms of management do exist. Fishing permits allow for the collection of lionfish by recreational scuba divers, educational and community based response programs have been developed to create a sense of ownership within coral reefs, and early detection and prevention measures have been instigated in threatened regions. This paper offers an overview of the risks associated with the lionfish invasion as well as a compilation of relevant management responses and current study on the efficacy of these management strategies in terms of their case study overview, policy implications, and effectiveness.
Outlining the invasion:
In the western Atlantic Ocean the term “lionfish invasion” refers to the rapid spread of two species of lionfish. Both species are covered with venomous spines, which are used predominantly to protect the fish from predation (Halstead et al. 1955). The lionfish is successful as an invasive species in part because of a lack of natural predation. “Despite recent evidence that tiger groupers (Mycteroperca tigris) and Nassau groupers (Epinephelus striatus) may prey on lionfish, such large body predators have been systematically over fished throughout the Caribbean, and thus are unlikely to substantially counter the invasive lionfish threat posed towards Atlantic coral-reef ecosystems” (Maljković et al. 2008) (Schram, 2011).
In addition to a natural resilience to predation, the diet of lionfish also makes them a successful invasive species. Their diet ranges from crustaceans, shrimp and gobiids to juvenile fish that are an integral part of established commercial and recreational fish stock (Morris and Akins 2009).
In a policy report compiled by Jonathan Schram for Duke’s Masters in Environmental Management program, Mr. Schram sites another report as follows: “Coral reef environments in these areas are already under tremendous pressure stemming from coral bleaching, overfishing, pollution, disruptive algal growth, and global climate change” (Wilkinson and Souter 2008) (Schram 2011). Despite these synergistic impacts the direct impacts from lionfish on coral reefs is not small. “In 2008 it was observed by Albins and Hixon that a single lionfish could reduce recruitment of reef fish populations on a Bahamian reef by 79% in just five weeks (Albins and Hixon 2008).” The impacts and consequences derived from a marine invasion on this scale are certainly enough to solicit an immediate and rigorous management response.
Selective removal fishing and grassroots community programs:
One proposed strategy for managing the lionfish invasion is through eradication of the species in the Caribbean, Cacaos and Florida coasts. This strategy has been instituted in some parts of the Caribbean and operates by harvesting the fish from specific geographic regions.
This process may be developed to include support from regional ecotourism industries such as nature tours, snorkel and dive operations and hospitality services. In a 2008 report Morris and his colleagues state, “Some tourist locations, such as resorts, are physically removing lionfish by spearfishing and hand nets to reduce the risk of swimmer interaction” (Morris et.al 2008). As Morris and his colleagues suggest, these small-scale approaches may have a role to play in managing the invasion but more information and tracking from such efforts is needed to prove their efficacy.
The list below synthesizes the main points from an excerpt written by Thomas Frazer and his colleagues in a publication in “Reviews in Fisheries Sciences” on the topic of selective removal of lionfish by local community members.
Documentation should include:
- Relationship between effort and removal of lionfish
- Rate of lionfish rebounds
- Rates of prey consumption by lionfish
- Size of lionfish
- Documentation of results and benefits of removal of lionfish
(Frazer et. al 2012).
Frazer supports his outline through a case study at Little Cayman Island. He states:
“This work yields the first quantitative estimates of catch per unit effort (CPUE) from multiple locations with similar physiographic characteristics, and it also sheds light on the potential effectiveness and benefits associated with a sustained removal effort… this feasible removal regime did lower densities and remove larger lionfish, which reduced detrimental predation and shifted predation pressure away from particularly vulnerable fish species” (Frazer et al. 2012).
In addition to the research compiled by Frazer, governmental response to the invasion has begun to take place. “Since 2000, National Oceanic and Atmospheric Administration (NOAA) researchers have partnered with non-governmental organizations, academics, and other federal and state agencies to develop a programmatic response to the lionfish invasion” (Morris, 2008, pg. 410).
The combination of scientific documentation of removal of lionfish and governmental intervention by governmental programs like NOAA are a step in the right direction towards culling the rapid growth of lionfish but it may not be enough. Three separate reports reach a mutual conclusion that “Given their current geographic range, rapid population growth, and tools presently available to natural resource managers, eradication of lionfish in the western Atlantic, Caribbean Sea, and Gulf of Mexico is unlikely” (Morris and Whitfield, 2009; Schofield, 2010; Albins and Hixon, 2011). This conclusion shows that a more effective method is needed to prevent long-term habitat and biodiversity loss from the lionfish invasion.
Legislated response, early detection and prevention funding:
The most proven and least expensive way to prevent the lionfish invasion is through early detection and implementation of prevention measures. This process requires staff and funding in order to operate effectively—in short someone has to be looking for lionfish in at-risk regions in order to see if invasions are starting.
Not only is the prevention of marine invasions like that of the lionfish necessary to preserve marine ecology and marine resources but it also holds legal merit through Executive Order 13112. Under the order,
“The NISC [National Invasive Species Council] is responsible for producing an integrative national management plan (NMP) for all invasive species occurring within the U.S. every two years…The plan was written in association with eight invasive species working groups, including research, early detection and rapid response, leadership and coordination, control and management, information management, communication and outreach, international agreements, and prevention” (National Invasive Species Council 2001) (Schram 2011).
If federal governments wish to be in compliance with mandates set forth by senator Carl Levin in 2007, then the western Atlantic lionfish invasion needs to be accounted for on the NISC’s upcoming report. Doing so will appropriate funds from a $39.5 million dollar budget (Schram 2011). Although any appropriated funds will certainly only be of small financial support, prevention plans are a justified investment that will save economic expense in the long term.
A team of scientists and researchers working in threatened regions to gather data and implement prevention measures is likely to be the most effective and cost-effective way to stop the spread of lionfish invasions. Staging task forces in critical habitats will also generate additional scientific research from which management planning can be developed.
The invasion of the lionfish in the western Atlantic Ocean is an exemplary case study of how fast marine invasions can spread. The impacts of an abundant lionfish population are unprecedented in ability to impact fragile marine ecosystems, and even small populations of adult fish are capable of causing fishery and reef ecosystem collapse. The management solutions that have been implemented to prevent, and in some cases treat, such an invasion have shown varied results and are still in their scientific infancy. In order to institute successful and cost-effective programs in the future, further funding for research and manpower is needed. Between Executive Order 13112 and successful management strategies in South Florida and the Caribbean, a legal and management precedent has been set. These models need to be extrapolated into neighboring regions to prevent further invasion. If fragile marine ecosystems are to be protected not only from the invasive lionfish but future invasive threats, management plans need the funding and government support so they can mature and develop effectively.
BRIGHTMAN CLAYDON, J. A., CALOSSO, M., & JACOB, S. (2008). The Red Lionfish Invasion of South Caicos, Turks & Caicos Islands . Proceedings of the 61 st Gulf and Caribbean Fisheries Institute, 61. Retrieved October 11, 2012, from http://cbm.usb.ve/sv/assets/Uploads/PezLeon/General/Brightman-Claydon-2009-Proc-Gulf-Caribb-Fish-Inst-61.pdf
This study documents trending patterns in lionfish populations, specifically in the Turks and Cacaos.
Morris, J. J., & Whitfield, P. E. (2009). Biology, ecology, control and management of the invasive Indo-Pacific Lionfish: An updated integrated assessment. NOAA Technical Memorandum, NOS-NCCOS, 99
Morris and his colleagues outline the environmental impacts associated with lionfish invasion and establish a need for management response.
Schram, J. (2011). POLICY AND MANAGEMENT OPTIONS FOR INVASIVE INDO-PACIFIC Lionfish IN U.S. WATERS. Duke Library, Nicholas School for the Environment. Retrieved October 21, 2012, from http://dukespace.lib.duke.edu/dspace/handle/10161/3691?show=full
This report synthesizes existing policy and management responses to the Atlantic lionfish invasion.
Thomas K. Frazer, Charles A. Jacoby, Morgan A. Edwards, Savanna C.
Barry & Carrie M. Manfrino (2012): Coping with the Lionfish
Invasion: Can Targeted Removals Yield Beneficial Effects?, Reviews
in Fisheries Science, 20:4, 185-191
This Report addresses the efficacy of selective removal of the lionfish through fishing efforts. It also describes data constraints associated with CPUE.