There is growing concern that lionfish will affect the structure and function of invaded marine ecosystems. Lead author, Stephanie Green, from Simon Fraser University (SFU), along with REEF Director of Special Projects, Lad Akins and other co-authors Aleks Maljković (SFU), and Isabelle Côté (SFU), documented a dramatic 65% decline in 42 species of reef fish eaten by lionfish over a two year period. The study, conducted off New Providence Island in the Bahamas, used data collected during REEF's volunteer lionfish projects to track the explosion of the lionfish population over time, and revealed that lionfish biomass increased from 23% to nearly 40% of the predator biomass on the study sites between 2008 and 2010. This study represents the first documented direct impact of lionfish predation on native reef fishes and highlights the importance of control programs to minimize impacts.
This seminal publication was created by REEF and our collaborators at NOAA, ICRI, the United Nations Environment Programme, Caribbean Environment Programme, SPAW-RAC, and the over 40 participants of the 2010 Caribbean Regional Lionfish Workshop. The guide provides best practices for lionfish control and management, including control strategies, outreach and education, research, monitoring, legal considerations, and ideas for securing resources and partnerships. By following these best practices, resource managers can reduce the local impacts of invasive lionfish in marine protected areas and other places of ecological and economic importance. Available online as a PDF through the link below. Also available as an ebook. Spanish edition also available (email reefhq@REEF.org for more information).
Members of REEF's Grouper Moon Project team, including researchers from Oregon State University, have been conducting annual monitoring of the size and color phase of individual Nassau grouper found at the spawning aggregation on Little Cayman in the Cayman Islands. During non-spawning periods Nassau grouper display a reddish-brown-and-white barred coloration. However, while aggregating they exhibit three additional color phases: “bicolor”, “dark”, and “white belly”. Each year, Grouper Moon Project researchers and volunteers use a video camera with lasers mounted on the camera housing. The divers focus the laser caliper equipped video camera on individual fish at the aggregation, capturing several seconds of footage for each fish. We later analyze the video to determine the length of the fish and record the color phase. This paper summarizes five years of video data. Our observations show that the relative proportion of fish in the bicolor color phase increases significantly on the day leading up to the primary night of spawning. The increase in the proportion of the bicolor color phase from 0.05 early in the aggregation to 0.40 on the day of spawning suggests that this color phase conveys that a fish is behaviorally and physiologically prepared to spawn. Additionally, 82.7% of fish exhibiting dark or white belly coloration early in the aggregation period suggests that these color phases are not only shown by female fish as was previously assumed in the scientific literature. This is just one aspect of the important marine conservation research being conducted as part of the Grouper Moon Project. To find out more, visit the Grouper Moon Project webpage.
Over the past decade, Indo-Pacific lionfishes have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. This paper uses data from the 20,000+ REEF surveys conducted in Florida since the early 1990s, along with other long-term data sources, to document the appearance and rapid spread of lionfishes in the Florida Keys. The results are the first to quantify the invasion of lionfishes in a new area using multiple independent, ongoing monitoring data sets, two of which have explicit estimates of sampling effort. Between 2009 and 2011, lionfish frequency of occurrence, abundance, and biomass increased rapidly, increasing three- to six-fold between 2010 and 2011 alone. In addition, individuals were detected on a variety of reef and non-reef habitats throughout the Florida Keys. Because lionfish occurrence, abundance, and impacts are expected to continue to increase throughout the region, monitoring programs like REEF's Volunteer Survey Project will be essential to document ecosystem changes that may result from this invasion.
The authors of this study observed grouper and and their associated reef fish assemblage using scuba and underwater stationary videography during a 7-mo period. Fifty-seven sites around Cape Fear, NC, were visited with stationary video and diver point counts of groupers were taken at each site. Data collected as part of the REEF Volunteer Fish Survey Project, as well as several other datasets, were used to compare with the study results. Similar to other comparative studies previously published, the authors found that different survey methodologies have varying success at detecting even common species.
REEF Advanced Assessment Team Member, Dave Grenda, recently co-authored a paper documenting behavioral observations of young Great Barracuda occurring on live bottom sub-tropical reefs primarily at Gray's Reef National Marine Sanctuary off the coast of Georgia. For the past three years Dave assisted University of Connecticut researcher, Dr. Peter Auster, in studying behavioral interactions of piscivores and their prey. During REEF surveys on these cruises, Dave and the other researchers documented young-of-year (YOY) Great Barracuda (those individuals that had very recently settled to the reef, and were between 2-3 inches in length) hunting YOY Tomtate and Silverside that were taking refuge under ledges. Groups of YOY Barracuda would attack, capture, and consume the prey. Prey that escaped the Barracuda retreated to reef edges and were often consumed by bottom-dwelling adult piscivores such as Black Sea Bass, Bank Sea Bass, and Scamp Grouper. These findings indicate that given the strong functional role the young Barracuda have on driving species interactions, greater attention should be given to the roles played by the wider diversity of YOY piscivores recruiting to reef communities.
Predicting and mitigating the effects of invasive Indo-Pacific lionfish Pterois volitans on Caribbean fish communities requires a thorough understanding of the species’ predation behaviour in the invaded range, including the types and amounts of prey consumed and how foraging patterns vary in relation to extrinsic conditions. We studied the activity levels and prey consumption rates of lionfish on 12 shallow coral reefs in the Bahamas in relation to time of day and prey availability. Lionfish predation rates and activity levels were significantly higher during crepuscular (dawn and dusk) periods than at mid-day. Available prey fish biomass was highest at dawn but lower at mid-day and dusk, suggesting that lionfish predation activity is not limited by prey availability alone. Our calculated average daily mass-specific prey consumption rates, which incorporated daily variation, was ~3 times the estimates obtained from studies of captive lionfish in their native range and of invasive lionfish observed only during the day. Our results will help to predict more accurately the effect of predation by invasive lionfish on native reef fish communities.
Hamlets are a group of colourful coral reef fish found throughout the Caribbean. Ten species of hamlet have been discovered and each can be easily recognized by its own distinct colour pattern. In some areas, as many as seven varieties can be found on a single reef. However, most hamlet species are only found at specific locations. The blue hamlet, for example, is found only in the Florida region. How these very different looking, yet very closely related species came to be has been a a subject of debate among scientists. Data collected by divers and snorkelers as part of the REEF Volunteer Fish Survey Project were used in a large analysis to better understand the patterns of evolution in these and other marine fishes. They found that even widespread hamlet species are not found everywhere, and identified high density hotspots for each species. Because different species hotspots overlap and many species have more than one hotspot, the results do not support the theory that hamlets originated independently when they were geographically separated in the past. The research also showed how ecological factors, such as competition for food or habitat, may influence how different hamlet species co-exist. To contact the lead author - firstname.lastname@example.org