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
Recent concerns about changing elasmobranch populations have prompted the need to understand their patterns of distribution and abundance through non-destructive sampling methods. Since scientific divers represent a small portion of the total number of divers worldwide, the use of non-scientific divers could drastically increase the number of observations needed to monitor broad-scale, long-term trends. Here, we use 83,940 surveys collected by trained volunteer divers to examine spatial and temporal trends of the most frequently sighted elasmobranch species in the greater-Caribbean, the yellow stingray (Urobatis jamaicensis). Despite being relatively common and listed as Least Concern on the IUCN Red List, little is known about the status of this species. In total, yellow stingrays were observed on 5,658 surveys (6.7% sighting frequency) with the highest occurrence in the regions surrounding Cuba. Overall, sighting frequency declined from 20.5% in 1994 to 4.7% in 2007—a standardized decline rate of −0.11. However, these trends were not consistent in all regions. The strongest decline occurred in the Florida Keys, the most sampled region, where trends were similar among all areas, habitats and depths. In contrast, sighting frequency significantly increased in Jamaica where large fishes are severely depleted. We discuss possible explanations for these changes including habitat degradation, exploitation and changes in trophic interactions. Our results suggest large-scale changes in yellow stingray abundance that have been unnoticed by the scientific community. Thus, our study highlights the value of non-scientific divers for collecting data that can be used to understand population trends of otherwise poorly studied species.
the mismatch between genetic and phenotypic divergence among deeply divided mtDNA lineages in a coral-reef goby, with the description of two new cryptic species from the Caribbean Sea
Long-time REEF supporters, Les and Keri Wilk of ReefNet, recently discovered and photographed a distinctively marked population of the Greenbanded Goby, Elacatinus multifasciatus, on the island of Utila, Honduras. The population was distinguished by a prominent red stripe across the cheek that is not found on other populations of Greenbanded Gobies, as well as more numerous green bars on the body. The Wilks contacted Dr. Ben Victor, a reef fish taxonomic expert, who conducted a regional genetic comparison of Greenbanded Gobies to evaluate hidden diversity within this colorful and cryptic reef fish. As part of the study, the REEF database was used to document the current geographic range of the species. Ben's results identified the unique looking fish to be a separate species that is now called the Redcheek Goby (E. rubrigenis). He also discovered that, based on genetic results, Greenbanded Goby along coastal Panama, despite looking just like others in the species, are most likely a distinct species that will now be called Panamanian Greenbanded Goby (E. panamensis)
In this early paper, staff from REEF and NOAA studied feeding ecology of the invasive lionfish (Pterois volitans). The authors collected stomach content data from fishes taken throughout the Bahamian archipelago. Three relative metrics of prey quantity, including percent number, percent frequency, and percent volume, were used to compare three indices of dietary importance. Lionfish largely prey upon teleosts (78% volume) and crustaceans (14% volume). Twenty-one families and 41 species of teleosts were represented in the diet of lionfish; the top 10 families of dietary importance were Gobiidae, Labridae, Gram- matidae, Apogonidae, Pomacentridae, Serranidae, Blenniidae, Atherinidae, Mullidae, and Monacanthi- dae. The proportional importance of crustaceans in the diet was inversely related to size with the largest lionfish preying almost exclusively on teleosts. Lion- fish were found to be diurnal feeders with the highest predation occurring in the morning (08:00–11:00).
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.
This report summarizes several years of work on Goliath Grouper to provide an understanding of adult ecology and behavior so that the population could be managed sustainably. REEF data were used to provide information on distribution patterns throughout the southeatern US and regional densities in Florida. The authors found high concordance between their quantitative reef survey data and the categorical abundance data collected by REEF volunteers, thus reducing uncertainty about use of REEF's population data for future stock assessments.
This was a predecision document prepared by NOAA’s Fisheries Service to evaluate the population status of five species of rockfish in the Puget Sound. REEF data were one of several datasets that were used by the fisheries scientists to make the evaluation. Based on the analyses, NOAA Fisheries proposed to list three populations of rockfish in Puget Sound and the Strait of Georgia for protection under the Endangered Species Act. The Georgia Basin populations of two of the rockfish species – canary and yelloweye – are proposed for “threatened” status. A third rockfish species – bocaccio – is proposed as “endangered.” Populations of all three rockfish species in the Georgia Basin, which encompasses Puget Sound and the Strait of Georgia, have been harvested at high levels, depleting their numbers. Rockfish, which are bottom dwellers, typically live long lives, and mature and reproduce slowly, making them especially vulnerable to overfishing. A final decision on the three will be made in the Spring 2010.