The Gulf of Mexico is a large body of salt water along the Southeastern United States (figures 1 and 2). Take a moment to look at how much area is covered by the Gulf of Mexico. The Gulf of Mexico is larger than the combined States of Texas, New Mexico, Arkansas, and Louisiana.

Think about trying to figure out whether a particular species of marine fish is swimming in the Gulf of Mexico. Now think about trying to figure out how many of these fish are swimming in the Gulf of Mexico, and where they are swimming. This identification and counting is a challenge for marine scientists. The Gulf of Mexico covers a large area, and fish and other marine animals are constantly moving. In addition, seeing large areas under the water’s surface can be difficult.

Citizens, and in particular people engaged in outdoor recreation, may be visiting areas far away from other people. Often, these people have opportunities to observe, count, and report what they have observed. By doing this, they can help scientists because scientists cannot be everywhere. SCUBA divers, for example, may dive in areas where scientists might not be.

The scientists in this study were interested in identifying how many of a particular fish species were swimming in an area of the Gulf of Mexico. The scientists wanted to compare the numbers reported by recreational SCUBA divers with the numbers reported by other methods for identifying and counting marine fish. Recreational SCUBA divers are people
who use SCUBA gear to dive and swim under water for pleasure.

You may have heard the phrase, “The only constant is
change.” This phrase means that most things on Earth change over time. Think about the world around you. Does this statement seem true to you?

Some scientists are changing their understanding of invasive species. Invasive species are species that are not native to the place they live and are likely to cause harm to the environment, the economy, or human health. Humans have moved many plant and animal species to new areas. In some cases, the movement of species has been accidental, and in other cases, it has been on purpose. In many instances, invasive species have caused ecosystems to change so much that native species are unable to thrive in the ecosystem.

Invasive plant and animal species rapidly reproduce in new habitats. Some scientists have noticed situations, however, in which invasive species do not cause the harm to these new habitats that might be expected. These invasive species seem to fill an ecological role in an ecosystem. For example, in the Western United States, an invasive tree provides habitat for an endangered bird species. In another situation, native Hawaiian flowers are pollinated by an invasive bird species where native pollinators no longer live. Invasive species might especially fill ecological roles where humans have destroyed native habitat.

Some scientists are expanding their view of invasive species. In some instances, for example, everything possible should be done to reduce the harm caused by an invasive species. Native ecosystems should be preserved if possible. In other instances, we should realize that invasive species are creating new ecosystems.

As you can see, scientific thinking can change as scientists observe the world around them. Think of another example of when scientific thinking changed as a result of new
observations. Think of an example of when your own thinking changed as a result of new observations. Do you think your thinking will continue to change? Why?

Over the past decade, humans have introduced two species of Indo-Pacific lionfish (Pterois volitans and Pterois miles) into the Atlantic Ocean (figures 3a and 3b).

These species have spread into the northwestern Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico (figure 4).

These fishes’ native ecosystem is the Indo-Pacific region (figure 5).

These fishes have been seen in a wide range of Atlantic marine habitats, including coral reefs, hard bottoms, seagrass meadows, mangroves, and oyster reefs (figure 6). Sightings in different habitats mean that Indo-Pacific lionfish are found across a wide area, making it difficult to track their expanding numbers.

Marine scientists use established methods to monitor the presence of different fish species in marine ecosystems. These methods include the use of underwater cameras and underwater remotely operated vehicles (ROVs) (figure 7).

In recent years, scientists have also provided online opportunities for citizens to report fish and other marine sightings. Lad Akins has also developed a method to tag lionfish (figure 8).  When a lionfish is tagged, its movements can be tracked.

In this research, the scientists wanted to compare the different ways that information is collected about Indo-Pacific lionfish in an area of the Gulf of Mexico. In particular, the scientists wanted to compare observations and sightings of Indo-Pacific lionfish by recreational SCUBA divers with scientifically taken photographs and ROV videos.

The scientists identified an area in the Gulf of Mexico where Indo-Pacific lionfish had been sighted. The scientists compared five sources of lionfish abundance data collected in this area (figure 9). The data collection spanned the time from the first recorded Indo-Pacific lionfish sightings in this Gulf of Mexico area in 2010 through the year 2012.

The first source of lionfish counts was from an underwater stationary camera used by the Southeast Area Monitoring and Assessment Program (SEAMAP). The program uses underwater photography to identify, count, and understand a range of marine life.

The second source of lionfish counts was from information provided by the Dauphin
Island Sea Lab (DISL). DISL uses underwater remotely operated vehicles (ROVs). The ROVs videotape artificial reef structures and the areas around the structures (figure 10). A reef is rock, coral, a sandbar, or other structure beneath the water’s surface. An artificial reef is a human-built structure meant to provide reef habitat for marine life. Sometimes boats or other materials are purposely sunk to create artificial reefs.

The third source of Indo-Pacific lionfish counts was the U.S. Geological Survey’s Nonindigenous Aquatic Species (USGS-NAS) database. The USGS-NAS database is like an online library where information is stored. This database enables the U.S. Geological Survey to monitor, record, and analyze sightings of nonnative aquatic species throughout the United States. Citizens, as well as scientists, can visit online and report sightings.

The scientists also used data reported into the Reef Environmental Education Foundation (REEF) database. REEF is a marine conservation organization. REEF trains recreational SCUBA divers as citizen scientists. These citizen scientist SCUBA divers report sightings of marine fish and other marine organisms.

The last source of information came from an online questionnaire. The questionnaire
asked 232 licensed Alabama spearfishers to report the number and location of their dives. The questionnaire also asked spearfishers to report any sightings or experiences with lionfish, to provide any photographs they had taken, and to describe their encounters in detail.

The scientists examined 1,411 photographs and videos recorded by the stationary cameras and the ROV (table 1).

The USGS-NAS database first recorded lionfish sightings in the Gulf of Mexico in 2010. However, lionfish were seen off the southeast coast of Florida as early as 1985. Reports indicated that most sightings were of 1 to 4 lionfish, although some reports showed
up to 50 lionfish per sighting. Lionfish were observed between 2 meters in depth in shallow seagrass meadow habitats and up to 40 meters in depth in offshore and artificial reef habitats. The REEF database did not have any lionfish sightings in the Gulf of Mexico before 2011.

Fifty-seven licensed spearfishers answered the questionnaire. These 57 spearfishers had participated in more than 14,000 dives. These SCUBA divers had an average of 13 years of experience and an average of 17 dives every year in the northern Gulf of Mexico. One-third of the spearfishers reported seeing lionfish during a dive. In total, spearfishers saw 1,303 individual lionfish. Of these, 82 percent were observed in 2011.

Although some of the lionfish sightings were spread out across the study area, most of the sightings occurred within the same area (see figure 9).

The scientists noted that spearfishers, SCUBA divers, and other citizen-based sources of lionfish counting were effective at documenting the rapid movement of lionfish into the study area. Therefore, citizens could play an important role in providing an early warning of other nonnative species as they move into new ecosystems.

All of the sources of lionfish counting examined by the scientists showed a similar pattern. Most sources showed lionfish moving into the study area in 2010 and their numbers increasing every year through 2012. The USGS-NAS database relies on volunteers and does not include a measure of effort. The scientists do not know how many times volunteers tried to observe lionfish as compared with the numbers they reported. This lack of information limited the usefulness of the USGS-NAS database.

The survey of spearfishers enabled the scientists to compare effort with lionfish abundance. From this survey of spearfishers, the scientists learned that information provided by a small group of people can provide important additional information about lionfish abundance.

The scientists noted that this particular project is just one example of how citizen scientists can assist scientists with understanding ecosystem changes. In this case, the scientists were better able to understand the rate and locations of nonnative fishes’ movement into a new ecosystem. Understanding other events, such as the impact of oil spills or hurricane damage, may also benefit from the involvement of citizen scientists. The popularity and improvement of mobile applications (apps) will provide even more ways for citizen scientists to report their observations. With improved mobile technologies, citizen scientists may become even more effective as contributors to science.