Author Archives: Krista Laforest, 2021 AAUS Mitchell

One fish, two fish…175 fish?!

Along with tracking individual stoplight parrotfish, Sparisoma viride, our team has been busy conducting behavioral observations and getting GPS tracks of four other species of parrotfish for a total of 175 fish follows! It has been interesting to see how these species’ behaviors differ. While striped parrotfish (Scarus iseri) pay little attention to other males and do not defend their space on the reef regularly, other species, like the redband parrotfish (Sparisoma aurofrenatum), interact with conspecific males by flaring their dorsal fins as if to say, “this is my area, stay out!”

The redband parrotfish, Sparisoma aurofrenatum, will flash its fins at intruders instead of chasing them away like other parrotfishes.

One of Josh’s goals for the summer is to get a better idea about how terminal phase stoplight parrotfish interact with other conspecific males to defend their territory on the reef. During multiple dives, Josh and I followed male stoplight parrotfish and categorize the type and the duration of interactions with both terminal and initial phase fish. While males regularly chase smaller “floater” males (i.e., fish that do not possess a territory) out of their territory, it appears that males of similar size that share territory boundaries interact less often and less aggressively. . This “dear enemy” effect has been observed in several other species, but never documented in parrotfishes! Males will often interact with females in their territories. These interactions are usually brief and appear to be over feeding spots. However, on occasion we would see males chase females completely out of their territories, suggesting that maybe these females were not part of their harem.

Collecting “dear enemy” data on parrotfishes
Photo Credit: Joshua Manning

In his previous work, Josh found that males of some species partition reef space into non-overlapping territories but share space with other parrotfish species. As part of Josh’s dissertation work, we wanted to observe how fishes interact within shared spaces. During days we were not diving, our team donned snorkel gear and headed to Invisibles and Aquarius to simultaneously track parrotfishes. During these tracks, I would follow a male stoplight parrotfish around the reef site while Josh followed a male queen parrotfish. For most of the follows, our fish generally did not interact much, often swimming by without paying any mind to the other. Occasionally, however, the two fishes would swim toward the same patch of the reef to graze. It was a moment of excitement for us on the surface – sometimes we would be so focused on following the fish and seeing which species got to graze at the coveted lunch spot that we would forget about the other person on the surface!

A terminal phase queen parrotfish, Scarus vetula, after briefly grazing on the benthic substrate continues swimming to find its next snack!

Josh hopes that these data will help us to better understand the drivers behind territory maintenance and space use in parrotfishes, which may have implications for the makeup of the underlying benthic community. This in turn could provide important insights into coral reef management to restore and maintain a healthy ecosystem.

The team is all smiles after wrapping up a great field season!

This summer has been packed full of field work both above and below the surface and I was able to learn a lot about the role of parrotfishes on coral reef ecosystems! I am so grateful that I was able to experience Bonaire for the first time with this amazing group of researchers. Thank you to Our World Underwater Scholarship Society and the American Academy of Underwater Sciences for providing me with the opportunity to be the 2021 Mitchell Internship, and to Josh Manning and the members of the McCoy lab at Florida State University for being such great hosts!

 

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Bon Bini na Boneiru!

As the 2021 American Academy of Underwater Sciences (AAUS) Mitchell Scientific Diving Intern for the Our World Underwater Scholarship Society (OWUSS), I will be assisting Ph.D. candidate Josh Manning with his dissertation research, along with other members of the McCoy Lab at Florida State University, Ph.D. candidate Ethan Cissell and undergraduate student Lena Kury! Josh’s research focuses on how parrotfish territoriality affects patterns of grazing intensity on the coral reefs of Bonaire. Parrotfishes are important grazers that use their beak-like teeth to scrape at the substrate, which helps to keep algae in check and creates bare space for juvenile corals to settle and grow. After several field seasons on the reefs of Bonaire, Josh noticed that males of some species, particularly the stoplight parrotfish Sparisoma viride, swim within well-defined territories and will chase off other males that enter these areas. This summer, we are recording the behaviors of several parrotfish species to better understand how these territories are defended and how they influence other aspects of parrotfish behavior.

After countless Zoom meetings working out travel logistics during a pandemic, three flights, multiple Covid-19 tests, and one last quarantine on Bonaire, our team was finally cleared to start conducting research! During our first few days of diving, we explored a few dive sites on the Northern leeward coast of the island, familiarized ourselves with everyone’s equipment, and ensured that we were weighted correctly so that we could practice proper buoyancy. As we descended onto the reef at Karpata, a historically well-studied site, I was instantly overwhelmed by the diverse species of corals thriving on the reef!  With reef-building coral species like Orbicella annularis providing small hiding spaces for creatures of all sizes, it was not surprising to see a diverse assemblage of fish species. We were even lucky enough to find a green sea turtle, resting on top of soft corals!

A graysby rests on Orbicella annularis, a foundational species of coral found on the reefs of Bonaire.

The view from the entry point at a popular dive site, Karpata.

After everyone felt comfortable in the water, it was time to get to work! A large portion of Josh’s research involves observing parrotfish behaviors, so we spent the next day practicing our fish identification skills! Parrotfishes are protogynous hermaphrodites that transition from an initial female phase to a terminal male phase based on social cues. These phases can have incredibly distinct colorations, so it is important to be able to differentiate when fishes are the opposite sex, or an entirely different species! While we will mostly be following terminal phase males this summer, it is important that we can also identify initial phase fish within each territory. This may help us to understand if males defend their territories from neighboring fishes to protect their preferred grazing spots, their mating opportunities, or a combination of the two!

Stoplight parrotfish coloration changes drastically from the initial phase female (top photo) to the terminal phase male (bottom photo).

On our first day of data collection, we dove at one of Josh’s predetermined study sites, Invisibles, to record the behaviors of the stoplight parrotfish S. viride. During these dives, Josh identified a fish to observe for 30 minutes, while Ethan and I counted the number of initial phase fishes present within its territory. Josh would then signal to Lena, who was snorkeling at the surface with a handheld GPS receiver, to begin tracking the movements of the fish. At first, it was really difficult to determine how many initial phase fish were in each territory – if only they would just stay still! This became easier with time, and soon I was able to enjoy watching the fish from afar as they were grazing the reef substrate, visiting cleaning stations, and defending their territories from intruders.

After a few days at Invisibles, we moved on to tracking S. viride at our second dive site, Aquarius. This time, I was in charge of GPS tracking as the top-side snorkeler. Viewing these fish from above made it much easier to discern the boundaries of each territory, and when intruding fish were attempting to sneak into the territories. While it is tricky to keep up with a fish that is chasing another male out of its territory, especially when swimming against the winds on top of a flotation device, it has become my favorite part of tracking the stoplight parrotfish! These chases help us determine the true boundaries of each fish’s territory, so that we can better understand the impacts of their grazing!

While Josh observes parrotfish behavior underwater, I snorkel with a GPS receiver to record fish movement and identify territory boundaries.
Photo credit: Lena Kury

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