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.
A new species of shrimpgoby was discovered by active REEF surveyor, Janet Eyre, while conducting REEF surveys in the Misool area of Raja Ampat in January 2019. Janet then communicated with authors, providing images and an exact location of where the fish was sighted, enabling the collection of type specimens. The new species was described and named after Janet - Janet's Shrimpgoby (Tomiyamichthys eyreae).
The study used almost 11,000 REEF Volunteer Fish Survey Project surveys collected between California and Alaska between 2006 and 2017 to evaluate the massive decline of the Sunflower Sea Star (Pycnopodia helianthoides). The authors documented a precipitous decline in the important species, primarily linked to the devastating sea star wasting disease epidemic that was wide-spread along the US and Canadian west coast starting in 2013, as well as warming ocean temperatures. In many places, the Sunflower Sea Stars have failed to return. A decline or absence of this species will likely lead to a boom of sea urchins, loss of kelp, and other cascading effects on the ecosystem. The study findings might prompt consideration of listing the species on the Endangered Species List.
A press release is available at http://news.cornell.edu/stories/2019/01/once-abundant-sea-stars-imperile....
This is the third paper that has used REEF data to evaluate the impacts of the wasting disease. The other two are described at these links: Devastating transboundary impacts of sea star wasting disease on subtidal asteroids (PLoS ONE) and Evidence for a trophic cascade on rocky reefs following sea star mass mortality in British Columbia (PeerJ).
This work was presented at the OCEANS19 meeting, and was a result of research done as part of the Grouper Moon Project. More than 800 species of fish produce sound including Red Hind (Epinephelus guttatus), Nassau Grouper (E. striatus), Black Grouper (Mycteroperca bonaci), and Yellowfin Grouper (M. venenosa). Their sounds can be used to monitor these fish and may be a means to estimate abundance if parameters such as source levels, detection probabilities, and cue rates are known. During the week of Nassau Grouper spawning in February 2017, a passive acoustic array was deployed off Little Cayman in the Cayman Islands to study the temporal and spatial dynamics of spawning aggregations of Nassau Grouper and Red Hind, and measure the source levels of the sounds produced by all four species. The localization method was based on hyperbolic localization of cross-correlated time differences of arrival and its accuracy evaluated via simulations and empirical measurements. The high number of localizations at fish spawning aggregations suggests that localization can be used to accurately measure source levels, detection ranges, and other variables needed for density estimation of spawning aggregations.
The authors of this study looked at how reef fish community assemblages have changed over time at several sites in Florida. In particular, they looked for evidence of biological homogenization (increasing species similarity between sites), which can alter the ecological function of systems as well as the economic value associated with ecosystems through complex socio-ecological dynamics. The authors used REEF survey data to measure biological homogenization by tracking taxonomic changes over a decade across 13 near-shore sites off the Atlantic coast of Florida. Sites that were closer to populated coastlines, or have been subject to substantial disturbance events, were more likely to show homogenization. Protected reef sites showed little evidence of homogenization. The authors postulated feedback mechanisms between societal values, diver practices, diver experience, and the severity of homogenization. The authors also discuss how baseline knowledge of the ecosystem could influence whether or not people are inspired to take action when baseline community structures change.
This paper provides an updated look at non-native marine fishes that have been reported from Florida waters, following up on two previous papers (Semmens et al 2004 and Schofield et al 2009). The paper, co-authored by staff from REEF and the US Geological Survey (USGS), also provides information on Early-detection/Rapid-response (ED/ER) efforts.
In addition to the well-known invasion of non-native lionfish (Pterois volitans and P. miles), there are now 39 other non-native marine fishes that have been documented in Florida. These reports have mostly come in from REEF's Non-Native Species Reporting Program (www.REEF.org/report-exotic-or-invasive-sighting), which are then input to the USGS’s Nonindigenous Aquatic Species database (USGS-NAS). In addition to lionfish, there is one other Indo-Pacific species, Regal Demoiselle (Neopomacentrus cyanomos), that is considered established, along with two other species that have expanded their natural range in the region (Fairy Basslet, Gramma loreto, and Tessellated Blenny, Hypsoblennius invemar). The rest of the species have not yet established populations.
In 1999, REEF established an ED/ER program to mobilize efforts to locate and remove reported non-native species from Florida waters. In collaboration with the USGS and public aquarium institutions (originally the National Aquarium and more recently the Phillip and Patricia Frost Museum of Science), REEF has coordinated the removal of 13 individuals of 9 species from Florida's coastal waters (see list below). An additional 4 species have been removed by other institutions Many of the captured fishes were transferred to public aquaria where they were displayed to provide educational information to the public.
As discussed in Semmens et al (2004), the origin of most non-native fish species sighted in Florida is intentional release by well-meaning home aquarium owners. REEF works with partners, including the Marine Aquarium Societies of North America (MASNA), to conduct outreach with the public on alternatives for responsible disposal of unwanted fishes.
Successful Non-native Fish Removals From Florida Coastal Waters Coordinated by REEF's ED/ER Program
Orbicular Batfish, Platax orbicularis (n = 5)
Humbug Damselfish, Dascyllus aruanus
Chocolate Surgeonfish, Acanthurus pyroferus
Foxface Rabbitfish, Siganus unimaculatus
Spiny Chromis, Acanthochromis polyacanthus
Orangespine Unicornfish, Naso lituratus
Lagoon Triggerfish, Rhinecanthus aculeatus
Yellow Tang, Zebrasoma flavescens
Purple (yellow-tail) Tang, Zebrasoma xanthurum
The authors, Eliza Heery and colleagues at the Seattle Aquarium, NOAA, and the University of Washington, used REEF sightings data on Giant Pacific Octopus (Enteroctopus dofleini) in Washington State to evaluate patterns of occurrence with urbanization. The species is the largest known octopus in the world, and they can reach over 20 feet in length from one tentacle tip to the other. The study objectives were to determine whether the distribution and habitat-use patterns of Giant Pacific Octopus were correlated with urbanization intensity on nearby shorelines in Puget Sound. REEF was instrumental in the study, providing data for a much larger spatial area and longer time period than would otherwise have been available. Heery et al. used REEF data in a series of statistical models and found that urban effects varied with depth. On deeper dives (> 24 m), REEF divers had a higher probability of encountering octopus in more urban locations.
Why might this be? The study's authors conducted additional field surveys to explore two potential explanations. To determine whether food resources played a role, Heery et al. collected middens – piles of shells leftover from past meals of octopus – from octopus dens throughout Puget Sound. Midden piles indicated there were no differences in the diets of urban octopus and rural octopus, suggesting that food resources were not the driver of urban-related distribution patterns. Secondly, they conducted a series of video surveys in sets of adjacent sites where there was a lot versus very little anthropogenic debris (junk). As many recreational divers might have predicted, they found more octopus in locations where there was a lot of junk.
How is this important for science? Past studies in urban ecology have suggested that mesopredators (mid-sized consumers) benefit from urbanization because of the food and shelter resources city environments provide, but those studies have focused exclusively on terrestrial mesopredators (like racoons and coyotes). This is the first study to examine whether marine mesopredators exhibit comparable patterns. It concludes that within certain habitats (deeper zones), octopus are indeed positively correlated with urbanization. Yet it is likely that shelter resources (from junk) rather than food are the driver.
During the summers of 2013 and 2014, populations of sea stars along the west coast from Alaska to Mexico were decimated by the sea star wasting disease (SSWD) epizootic. Two of the most highly affected species along this range were Pisaster ochraceus (the Ochre Sea Star), the most common intertidal species, and Pycnopodia helianthoides (the Sunflower Sea Star), the most common subtidal species, both of which are endemic to the US western coast. REEF Volunteer Fish Survey Project were used to evaluate populations of the Sunflower Star as part of this study (REEF surveyors do not monitor Ochre Stars because they are intertidal). The REEF data showed an extraordinary decimation of Sunflower Sea Stars, with no sign of recovery three years after the SSWD epizootic. In contrast, data collected by the authors on Ochre Stars in the San Juan Islands revealed high fatality rates (over 90%) associated with SSWD during the summer of 2014, followed by low levels of disease in the summers of 2015, 2016, and 2017. Population levels of Ochre Stars following the epizootic remained stable but small, and shifted in size structure from larger to smaller stars. Extremely low population size of Sunflower Stars raises concern about the capacity of this species to recover, as well as to resist other stochastic events in the future. These findings were presented at the Salish Sea Ecosystem Conference in Seattle, WA, in 2018.
Statistical habitat models, such as generalized linear models (GLMs) and generalized additive models (GAMs), are key tools for assisting Ecosystem-based Fisheries Management (EBFM) efforts. These models can be used to map species distributions and assist in marine protected area (MPA) planning. In this study, the authors applied a statistical methodology to produce preference functions for fish and invertebrates along the West Florida Shelf, and then mapped the hotspots of juveniles and adults of three economically important species (Red Snapper, Gag, and Red Grouper) for informing future MPA planning. The analysis used a comprehensive survey database that included all encounter and nonencounter data of the study ecosystem collected by fisheries‐independent and fisheries‐dependent surveys. The REEF Volunteer Fish Survey Project dataset was one of 37 used in the analysis.