The impacts of invasive lionfish (Pterois volitans/miles) on native coral reef populations in the Western Atlantic Ocean and Caribbean Sea can be enormous. However, how much lionfish differ from native predators and whether their effects outweigh the abundant mesopredators that occupy many reefs invite continued examination. The authors of this paper present empirical evidence from Caribbean Panama and beyond, suggesting that lionfish are less abundant than native mesopredators (e.g. small seabass). In addition, their findings show that direct impacts by lionfish and Graysby, a native mesopredator, on survivorship and size distributions of one native prey species (Masked Goby) are similar. The authors used REEF data collected from sites throughout the Caribbean, Gulf of Mexico, and Western Atlantic from 2010-2015 to test whether lionfish were less common than Graysby. By leveraging the citizen-science dataset collected by REEF volunteers, the authors were able to evaluate the impacts of native and non-native mesopredators across a much broader geographic region and longer time period than otherwise possible based solely on surveys conducted as part of their field work, which were limited to just one year in Caribbean Panama. REEF data substantially enhanced the evidence used to show that lionfish tended to be much less common than Graysby over the 6-year period. The findings of this paper will help guide lionfish management and control, and provides support for synergies between conservation actions aimed both at the invasion and other consequential problems such as overexploitation and climate change.
2021
Designing effective local management for invasive species poses a major challenge for conservation, yet factors affecting intervention success and efficiency are rarely evaluated and incorporated into practice. As part of a multi-year study with funding from NOAA Coral Reef Conservation Program and others, REEF and partners coordinated regional efforts by divers to cull invasive lionfish (Pterois spp.) on 33 U.S. Atlantic, Gulf of Mexico, and Caribbean protected coral reefs from 2013 to 2019. During each effort, the researchers estimated removal efficiency and efficacy as a function of environmental and habitat conditions, invasion status, and personnel expertise. Highly experienced individuals culling during crepuscular periods (2 hr from sunrise/sunset) are three times more efficient (in terms of minutes) than novice divers during midday, suggesting: (a) retention of experienced individuals is key for efficient programs, and (b) planning culls with personnel and time of day in mind increases the number of sites covered with the same effort. Lionfish behavior and habitat characteristics had little effect on removal efficiency and efficacy, but divers had higher capture success at reefs with higher lionfish densities. The authors suggest reefs with persistently low densities of lionfish be given low priority for management efforts, given that impacts to native fauna are unlikely and culling effectiveness declines to <50% below this level. Incorporating efficiency factors in spatial management planning along with estimates of lionfish density can help ensure that limited resources for control are extended across a greater range of invaded habitats.
Fish usually need to be caught to be measured, but scientists from the Grouper Moon Project and Cayman Islands government have used video camera systems to collect an impressive 17-year dataset of Nassau Grouper lengths from Little Cayman. We combined this with information on growth and abundance to produce a comprehensive assessment of Nassau Grouper on Little Cayman. We found that Nassau Grouper recovered on Little Cayman largely thanks to one strong year class from 2011 spawning, 4-8x average. Length data from Cayman Brac also showed signs of a strong 2011 year class and substantial improvement in population status in recent years. Our analysis demonstrates that video camera systems are effective for monitoring protected fish spawning aggregations and are especially promising for situations where catch, effort, and invasive length data are unavailable.
With 15,000 tube feet and up to 24 arms, the magnificent Sunflower Sea Star (Pycnopodia helianthoides) is found from Baja Mexico to Alaska. Since 2013, this magnificent species has suffered a dramatic decline due to a wasting disease. Many fear that the species may be on the brink of extinction. To quantify the decline and possibly establish grounds for protections and intervention, REEF joined in a partnership of more than 60 institutions led by The Nature Conservancy and Oregon State University. REEF provided data collected through the Volunteer Fish Survey Project to help establish whether the Sunflower Sea Star warranted listing on the International Union for Conservation of Nature (IUCN)’s Red List of Threatened Species. REEF shared data from 32,517 REEF surveys conducted at hundreds of sites between California and Alaska from 1998 to 2019, which included 18,035 records of the Sunflower Sea Star. Thanks to the efforts of our volunteer surveyors, REEF was able to contribute almost a third of the data used in the IUCN assessment.
The analysis found a 90.6% decline in the species. The resulting report was issued to the IUCN in fall 2020 and in December of that year, it was announced that the Sunflower Sea Star was placed on the IUCN Red List as Critically Endangered, just one step below extinction. The decline has had cascading impacts on the marine environment. Sunflower Sea Stars are a main predator of sea urchins, whose populations have now exploded in many regions. Higher numbers of sea urchins, which feast on kelp, has led to “urchin barrens” and a significant decline in kelp forest ecosystems.
This paper evaluates population trends in Giant Pacific Octopus (GPO) in the Pacific Northwest using REEF Volunteer Fish Survey Project data and other data sources. The authors found large changes in GPO abundance linked to average water temperatures. GPO sighting frequencies ranged from a high of 39% to a low of 11%. For every additional degree increase of 4-year average temperatures, the Puget Sound GPO sighting frequency dropped about 19 points. That’s a loss of roughly 75% of typical diver sightings for every degree C. The authors also noted that, of the many datasets they used to conduct the analysis (including a transect study in Prince William Sound focused on GPO), the REEF dataset provided the most comprehensive set of information on GPO populations and provided the strongest correlation coefficients.
Managing invasive Indo-Pacific lionfish (Pterois volitans and P. miles) in the Western Atlantic Ocean is beyond the capacity of natural resource organizations alone. In response, organizations have mobilized members of the public and citizen scientists to help. The authors used a structured survey to assess the activities and perceptions of 71 organizations that engage the public and citizen scientists in lionfish research and management throughout the invaded range of the Western Atlantic. REEF's work as part of our Invasive Species Program is one of five case studies included in the paper. The case studies highlight the varied and multi-pronged approaches to engagement of the public and citizen scientists in lionfish control, monitoring, and knowledge-sharing.
Since 2006, REEF has been working in close partnership with government agencies and partners throughout the region to help develop lionfish response plans, train resource managers and dive operators in effective collecting and handling techniques and conduct cutting edge research to help address the invasion.
Predation by the invasive Indo-Pacific lionfish impacts native fish populations within the Caribbean region and threatens to expand further into Brazil and the Mediterranean. Identifying the range-restricted native fish species with high predation vulnerability in these areas ahead of the invasion front combined with the knowledge of the time a lionfish population typically takes to reach dangerously high densities could help conservation planners attain positive outcomes and reduce biodiversity loss. This study estimated the vulnerability of all Caribbean and endemic Brazilian shorefishes to lionfish predation based on seven ecological and biological traits (e.g. body size, habitat preference, etc.). To facilitate the traits analysis, REEF interns compiled data on the body shape of 1,500 Caribbean fishes. Results from that analysis identified 77 Caribbean and 29 Brazilian species with high vulnerability (i.e. small and narrow-bodied reef fishes) and restricted ranges. The REEF Volunteer Fish Survey Project dataset from the Tropical Western Atlantic was then used to test whether this vulnerability score could explain the species' presence in the lionfish diet by using REEF survey data on the average abundance of fish species documented in published lionfish diet field studies conducted in six Caribbean regions. The same REEF dataset was also used to estimate the rate of relative lionfish abundance increase from initial lionfish sighting to peak local density. Those results showed that an average of five years (and a median of nearly 2 years) elapses from first sighting to maximum observed lionfish densities. These findings support that control measures implemented at the invasion front (in places like Brazil) ahead of the ~two-year lag to peak lionfish density may avert species’ extirpation. This finding is especially critical for places like Brazil, where 12 range-restricted reef fishes occur only in oceanic islands, and management intervention could have a large impact. In addition to Brazil, spatial richness analyses revealed hotspots of vulnerable species in The Bahamas, Belize and Curaçao.
2020
This paper, a chapter in a book on Marine Disease Ecology, focuses on global disease outbreaks that have resulted in mass mortality events that have subsequently impacted marine communities. One of the four case studies in the paper is the Sea Star Wasting Disease (SSWD) event that impacted the west coast of the US and Canada beginning in 2013. Data collected by REEF surveyors in this region on several species of echinoderms have been the basis of multiple published studies on the impact of SSWD. These studies are referenced in the book chapter.
This paper summarizes research done as part of the Grouper Moon Project to understand sound made by several species of grouper. Many fishes produce calls during spawning that aid in species and mate recognition. When multiple sound-producing species inhabit an area, the detection range may decrease and limit call function. Acoustic partitioning, the separation of calls in time, space, or spectral frequency, can minimize interference among species and provide information about fish behavior and ecology, including possible response to increasing anthropogenic noise. The authors investigated acoustic partitioning among 4 sound-producing epinephelids, Nassau Grouper Red Hind, Black Grouper, and Yellowfin Grouper, using passive acoustic data collected at the mass spawning aggregation site on the west end of Little Cayman in the Cayman Islands during the spawning seasons of 2015 to 2017. Results indicate separation in space and time between species calls, which aids in acoustic partitioning. When this separation did not occur, unique call structures were present, which may aid in effective intraspecies communication.
This paper presents exciting results from the Grouper Moon Project, documenting conservation success for endangered Nassau Grouper. Results of the analysis showed that on both Little Cayman and Cayman Brac in the Cayman Islands, Nassau Grouper spawning aggregations have more than tripled in response to adaptive management by the Cayman Islands government over a decade. On Little Cayman, the aggregating population grew from around 1,200 fish in 2009 to over 7,000 in 2018. The study used a two-pronged approach that included tagging and video census data for monitoring and counting Nassau Grouper populations in an effort to more accurately estimate annual numbers of fish in the population, and thus provide insight into the effects of ongoing conservation efforts. While many governments have enacted regional or seasonal fishing closures in an attempt to allow recovery of overfished stocks of aggregating reef fishes, this is the first study to provide evidence that these measures can be successful across multiple decades.
The paper was authored by a collaborative team of researchers from Reef Environmental Education Foundation (REEF), Cayman Islands Department of Environment, Scripps Institution of Oceanography, and Oregon State University. The Grouper Moon Project represents nearly 20 years of research, monitoring, and outreach efforts, coordinated by REEF and Cayman Islands Department of Environment, in collaboration with researchers from Scripps Institution of Oceanography and Oregon State University. It is the Caribbean’s oldest continuous grouper spawning aggregation research program, and represents one of the most advanced, multi-faceted tropical fisheries research programs in the world. Due to overfishing during spawning, Nassau Grouper have suffered region-wide stock collapse. By the 1980s large aggregations had all but disappeared from the Caribbean region. Of the remaining aggregations, few contained more than 1,000 individuals and the species is currently listed as critically endangered by the International Union for Conservation of Nature. The aggregation on Littl Cayman is the largest known for this endangered reef fish.