Publications

Tropical regions are, in general, more diverse than ecosystems at higher temperate latitudes. A commonly held hypothesis is that the diverse predators in tropical regions cause predation to have a relatively stronger role in shaping communities. Data from the REEF Volunteer Fish Survey Project (VFSP) were used by Michele Repetto and colleagues from the Smithsonian Tropical Research Institute to test for underlying differences in regional fish diversity that could contribute to variation in predation intensity and impact. Their study spanned across the Isthmus of Panama, including two tropical ocean basins. The research team combined field experiments and VFSP data collected by REEF volunteers from both the Tropical Western Atlantic (TWA) and Tropical Eastern Pacific (TEP). Their findings demonstrated that while the influence of predation is highly variable, even within tropical systems, increases in predator diversity due to localized abiotic factors (e.g. seasonal upwelling) led to an increased influence of predators on their prey base.

The study's authors observed striking spatial and seasonal variability in predation impact and intensity on coastal marine invertebrate communities. This variability likely has important consequences for food web dynamics and patterns of species diversity and ecosystem functioning. The Isthmus of Panama offered a unique opportunity to explicitly test factors that influence temporal and spatial variability of predator effects in tropical marine communities. The analysis included data on115 fish species from 16 families in the TWA and 89 species from 18 families in the TEP. Because the REEF VFSP program occurs world-wide, this citizen science dataset provides a valuable source of information to scientists and researchers from government and academic institutions that is otherwise not available.

Citizen science is growing increasingly important for managers and conservation science. The REEF Volunteer Fish Survey Project provides an accessible and flexible way for divers to contribute observations to a large database. This flexibility comes with challenges for analysis, but these challenges can be addressed with analytical models that account for variation in survey effort in time and space. For this study, the authors used simulations as well as data collected in The Bahamas and Turks and Caicos from 1994–2020 to identify model approaches that were able to predict trends in both observation frequency and abundance at the survey level as a function of dive duration, location, and other covariates. The models identified a significant decline in Queen Triggerfish, which was used as a model organism for this study. This research opens the door for more in depth study of other understudied reef dwelling species, allows for higher resolution modeling of predictors of presence and abundance, and expands the set of tools available for researchers using REEF data.

The Salish Sea in Washington and British Columbia is home to hundreds of fish species, and REEF citizen scientists play an important role in documenting and monitoring the health of fish populations in this biologically diverse region. This paper shows that the REEF Volunteer Fish Survey Project helped monitor more than half of the total fish species known to occur in the Salish Sea. Furthermore, REEF surveyors expanded the known range of multiple species within the ecosystem and documented the presence of a fish species not previously known to occur in the Salish Sea — the Striped Kelpfish (Gibbonsia metzi). 

The research was led by SeaDoc Society. SeaDoc has partnered with REEF for almost two decades to help train volunteer divers in the Pacific Northwest. REEF citizen scientists have been surveying the Salish Sea since 1998. The study was also informed by a list of species published by fisheries biologists Theodore Pietsch and James Orr, which reported on 261 known fish species from the Salish Sea. The authors compared data from 13,000 REEF surveys collected from about 800 sites in the Salish Sea over 21 years (1998-2019). Volunteers observed 138 of the 261 species and expanded the range of 18 species, meaning they were spotted in an area of the Salish Sea where they previously had not been documented to exist.

Not all fish species have an equal chance of being spotted by a scuba diver. Some might live hundreds of feet deep, expertly hide themselves, or only rarely venture into the Salish Sea. The authors took this into account and categorized each fish based on its potential for encounter by a diver. REEF divers sighted 85% of fish species that lend themselves to visual observation. For these fishes, experienced citizen scientists can expand what scientists know about range, life history, population status, size, age, behavior, and more.