In this paper, authors use data regarding where REEF divers did or did not encounter three species of fisheries importance: red snapper, red grouper, and gag grouper. They then combined these data with 36 other data sets, each sampling different areas of the Gulf of Mexico, and created distribution maps for use in ecosystem models of the Gulf of Mexico. These distribution maps picked up fish hotspots that are not identifiable by any individual data set, highlighting the complementary nature of the REEF data.
The study used REEF's Volunteer Fish Survey Project database to produce a new map of marine fish biodiversity across the Caribbean and tropical western Atlantic. The work, performed by scientists from the Center for Macroecology, Evolution & Climate in Denmark and the Marine Biological Association, studied REEF’s extensive data base collected by our volunteer surveyors to produce the map and find that fish biodiversity is strongly linked to sea temperatures. However, results also show that while fish biodiversity is higher in warmer waters, the very hottest sites in fact have fewer species than sites with intermediate temperatures, something not shown before in previous studies. These results will be of concern given the rising water temperatures in the region. For more details, see this REEF enews article.
REEF fish survey data collected from Bonaire in 2015 were used to help evaluate the impact of terrestrial degradation on nearby coral reefs, specifically investigating the link between vegetation ground cover and tree biomass index to coral cover, fish communities and visibility. The authors found a positive relationship between ground cover and coral cover below 10 m depth, and a negative relationship between tree biomass index and coral cover below 10 m. Greater ground cover is associated to sediment anchored through root systems, and higher surface complexity, slowing water flow, which would otherwise transport sediment. The negative relationship between tree biomass index and coral cover is unexpected, and may be a result of the deep roots associated with dry-forest trees, due to limited availability of water, which therefore do not anchor surface sediment, or contribute to surface complexity. The analysis provides evidence that coral reef managers could improve reef health through engaging in terrestrial ecosystem protection, for example by taking steps to reduce grazing pressures, or in restoring degraded forest ecosystems.
Over the half-century since the original Alligator Reef survey, there have been great advances in the taxonomy of Greater Caribbean reef fishes, with numerous changes in scientific names and classification. As part of the update these changes are addressed so as to bring the list to current status.
In 2013 the junior authors (REEF Advanced Assessment Team members) undertook a four-year census of the fishes of the area with a goal to photo-document as many of their sightings as possible. This effort has subsequently entailed 1039 combined dives devoted to fish counts, photographic documentation, or both. During these surveys, they have photographed 278 of the species reported by Starck (1968) plus 35 additional and/or newly described or reclassified species not recorded in the earlier study.
An update of the checklist of fishes of Alligator Reef and environs some fifty years later provides an unparalleled opportunity to evaluate the species richness for a limited reef area, as well as a unique opportunity to explore changes in diversity over a half-century time scale. In the updated study the authors added 107 species and subtracted 5 from the original total of 516 species: thus the checklist now totals 618 species, of 122 families, the most recorded for any similarly sized area in the New World. The additional species records are made up from a number of subsequent collections as well as from a comprehensive effort by the junior authors.
Among the other databases of relevance to the study area used for comparison, the Smithsonian Tropical Research Institute (STRI) Shorefishes of the Greater Caribbean by D.R. Robertson & J. Van Tassell and that of the Reef Environmental Education Foundation (REEF).
REEF maintains an online database of worldwide visual fish-count surveys conducted by volunteer researchers and fish-count enthusiasts. While such surveys are biased towards easily observed species, they are indicative for a large portion of the reef fish fauna and comprise a valuable source of comparative information (Schmitt & Sullivan 1996, Pattengill-Semmens & Semmens 2003, Holt et al. 2013). The local REEF data includes that of the Estapés, who have conducted 185 roving-diver REEF surveys on Alligator Reef. An additional 1807 surveys at 94 sites in the study area have also been conducted by other REEF volunteers (as of July, 3, 2016).
Like many places throughout the Caribbean, Nassau Grouper spawning aggregations in the US Virgin Islands were overfished until their disappearance in the 1970s and 1980s. In the early 2000s, however, Nassau Grouper were found gathering at Grammanik Bank, USVI, a mesophotic coral reef adjacent to one of the extinct aggregation sites, and regulatory protective measures were implemented to protect this fledgling aggregation. The authors of this study addressed two objectives: 1) which factors (local vs. external recruitment) are important in shaping recovery of the USVI spawning aggregations, and 2) the impact of severe past overfishing on the genetic structure of the Gremmanik Bank aggregation. For this second objective, REEF Grouper Moon Project scientists provided genetic samples from individual Nassau Grouper taken from the Little Cayman spawning aggregation, a much larger and less impacted aggregation.
No population structure was detected between the USVI and Cayman spawning aggregations. Additionally, the USVI spawning population showed signs of a genetic bottleneck, typical of greatly reduced populations. These collective results suggest that external recruitment is an important driver of the USVI spawning aggregation recovery. These findings also provide a baseline for future genetic monitoring of the spawning aggregations.
Sea star wasting disease has devastated sea star populations on the West coast from Mexico to Alaska. The disease broke out in 2013, causing massive death of several species of sea stars. Infected animals develop lesions that eat away tissue, with limbs dropping off as the animals die. The disease has been linked to a virus, although environmental factors may also be involved. This study presents an analysis of REEF survey data on several asteroid species collected by divers in the Salish Sea over the last 15 years.
The results showed that some species were hit hard, while others increased in number. Populations of sunflower sea star (Pycnopodia helianthoides), an important keystone predator in the region, dropped dramatically after the beginning of the epidemic. Several other sea star species, including the spiny pink star (Pisaster brevispinus) also declined. Numbers of the less-common leather star (Dermasterias imbricate) and two species of sea urchin, which are prey for sea stars, increased after 2013.
The virus outbreak continues, and will have lasting effects on the ecosystem. Sunflower sea stars have effectively disappeared from the Salish Sea, the study concludes. Likely as a result, numbers of urchins have increased, which in turn will lead to more browsing on kelp. As a result, study co-author, Dr. Joe Gaydos, and his colleagues are currently in discussions with the National Marine Fisheries Service to get the sunflower sea star listed as a “species of concern.”
The US Pacific Northwest and western Canada experienced a mass mortality of sea stars between 2013 and 2015. The sunflower star (Pycnopodia helianthoides), a previously abundant predator, began to show signs of a wasting syndrome in early September 2013, and dense aggregations disappeared from many sites in a matter of weeks. REEF surveyors certainly noticed, and the decline was reflected in the REEF database. The authors used the REEF database to document the decline regionally, along with a four-fold increase in the number of green sea urchins (Strongylocentrotus droebachiensis). The sea urchin increase also resulted in declines in kelp canopy coverage. This type of ecological change or trophic cascade, is where a change in one species impacts many others. Because of the long-term and wide-spread nature of the REEF survey program, our data have proven invaluable in documenting the impacts of the seastar wasting disease.
This paper is the introduction to a special issue of the journal, Marine Ecology Progress Series, titled "Invasion of Atlantic coastal ecosystems by Pacific lionfish". The issue is a compilation of papers presented at the 2015 special session of the Gulf and Caribbean Fisheries Institute meeting, which was co-organized by REEF and partner organizations. New findings include mechanisms that enhance the success of the invader, the extremely broad and variable diet of invasive lionfish, the ecological effects of the invader on native fish populations in various environmental contexts, and non-consumptive interactions between invasive lionfish and native predators. The entire issue is available online at http://www.int-res.com/abstracts/meps/v558/#theme.
The authors of this study examined drivers of public involvement and success at invasive removal in tournaments (derbies) to catch Indo-Pacific lionfish (Pterois volitans/miles) in the Western Atlantic. Information on 69 lionfish derbies held in the wider Caribbean region from 2010 to 2015 was compiled, including REEF Lionfish Derbies. The authors found that the number of lionfish caught increased with effort and with time since lionfish were established in an area. They also found that derby participation was best predicted by national wealth (GDP per capita) and number of local dive shops. These findings support that, from the point of view of public engagement, derbies should be held in areas where lionfish are well established, and where the pool of potential participants is large. However, alternative strategies may be more effective in areas where few lionfish are present.
A diminutive, non-native damselfish (Neopomacentrus cyanomos) was recently discovered inhabiting coral reefs near Veracruz, Mexico—far removed from where it is native in the Red Sea and the Indo-Pacific. This publication, co-authored by REEF's Director of Special Projects, Lad Akins, evaluates the threat of establishment and spread in the invaded range.
The quantities found in the Gulf of Mexico (GOM) suggest that the fish has already established a self-sustaining population in this new ecosystem. There is understandable concern, therefore, that this new arrival may become invasive and spread, yet the invasion risk imposed by this fish has not been assessed. In this study, a computer model was employed to deliver a forecast of the potential range of incursion of the damselfish in the GOM spanning 5 years. The model incorporated oceanic water flow in the region, tolerances of this damselfish to the ocean environment, and their reproductive strategy in order to supply a temporal and spatial forecast of their spread. From this study, targeted early detection and removal of the fish can be directed if the fish is deemed a threat to native fauna. On the basis of this work, it is foreseeable that the reefs presently harboring Regal Damselfish will likely see increased abundance of this damsel. Immediate attempts to eliminate the fish, therefore, should be focused in nearshore shallow waters spanning Veracruz to Frontera, Mexico. Further, water flows in the southern GOM are not widely conducive to long-distance transport of marine organisms with pelagic larvae, reducing the risk of this damsel permeating the greater GOM over 5 years. Aside from Regal Damselfish, this study implicitly adds to mounting evidence supporting a biogeographic disconnect between the Veracruz reef complex and the greater GOM and the Caribbean.
REEF surveyors are on the lookout for Regal Damselfish in the Gulf of Mexico and western Caribbean.