Gnathiid Gnation

New Open Access Publication from Gnathiid Gnation!

10 January 2023

Hot off the press! The latest publication to come out of Gnathiid Gnation is the first from Ph.D. candidate Clayton Vondriska‘s dissertation research! The paper “Assessment of a new olfactometer for study of sensory ecology in small aquatic organisms” is an Open Access paper available in Limnology & Oceanography: Methods. The paper can be accessed at:

Congratulation to Sam Russell!

30 December 2022

In August of this year Gnathiid Gnation member Sam Russell finished her Master’s degree! A huge congrats to her and we can’t wait to see what she does next!

Congratulation to Matt Nicholson!

13 December 2022

Congratulations to DR. Matt Nicholson for successfully defending his dissertation this morning! Featuring a special message from Steel Pulse’s Amlak Tafari! (Click here to check out the video)

Collaboration for Implementation of New Marine Olfactometer

29 November 2021

Over the past month Ph.D. student Clay Vondriska has been working with Dr. J. Rudi Strickler of the University of Wisconsin-Milwaukee on the use of a newly developed marine olfactometer. This machine allows for multiple sources of water to flow through a choice arena where an organism is held and allows that organism to show preference for or avoidance of certain stimuli. Clay will be using this marine olfactometer as part of his dissertation investigating the sensory ecology of gnathiids!

Moving to Miami

20 September 2021

We are excited to announce that Gnathiid Gnation will be moving the the University of Miami’s Rosenstiel School of Marine and Atmospheric Sciences beginning Fall 2021!

New Publication on Blood-borne Parasites in Caribbean Damselfish

12 May 2021

Gnathiid Gnation’s newest publication titled “Environmental correlates of prevalence of intraerythrocytic apicomplexan infecting Caribbean damselfish” was published this month in Parasitologia. In this paper, researchers infection rates of Caribbean damselfish and their impacts on their hosts. The open access article can be found HERE.

Gnathiid Gnation resumes work in The Philippines

12 April 2021

Led by Mary Shodipo and generously sponsored by the National Geographic Society, and in collaboration with colleagues at Silliman University, we are examining the impacts of the COVID-19 pandemic on local marine protected areas.

New Collaborative Publication Shows How Climate Change May Affect Gnathiids!

9 October 2020

The newest paper to come out of Gnathiid Gnation title “Effect of Acute Seawater Temperature Increase on the Survival of a Fish Ectoparasite” investigates how increasing water temperatures will effect gnathiid isopods. This was published in the journal Oceans with collaborators in The Philippines and Australia. Click HERE to check it out!

New Publication on Gnathiid Host-Finding Behavior & Host Susceptibility!

7 August 2020

Our newest paper “Differentially susceptible host fishes exhibit similar chemo-attractiveness to a common marine ectoparasite” investigates host preference and the forces driving host susceptibility. It was published in the journal Symbiosis and can be found on their website HERE or downloaded for free HERE.

Another New Publication from Gnathiid Gnation!

June 24, 2020

Check out Gnathiid Gnation’s latest paper, “The effects of environment and ontogeny on the skin microbiome of two Stegastes damselfishes (Pomacentridae) from the eastern Caribbean Sea” that has just been published in Marine Biology! Check it out HERE!

New Publication for Gnathiid Gnation!

June 9, 2020

Ever wonder how we breed and raise the gnathiids used in all our studies? Check out the newest publication to come out of Gnathiid Gnation to find out how! “Practical methods for culturing parasitic gnathiid isopods” will be officially published in the International Journal of Parasitology this month! You can find here!

New Gnathiid Gnation Publication!

May 26th, 2020

Catestrophic events like hurricanes can substantially alter eco-evolutionary processes and dynamics and the effect of these events is poorly understood when it comes to the their effects on genetic patterns of species. Members of Gnathiid Gnation and our collaborators at the University of Porto in Vairão, Portugal examined the effects of one of the worst hurricane seasons in the North Atlantic in recorded history on the genetic diversity of the Caribbean gnathiid isopod, Gnathia marleyi in the article “Hurricane-induced disturbance increases genetic diversity and population admixture of the direct-brooding isopod, Gnathia marleyi” published in Scientific Reports this month. Check the article out HERE!

New Publication from GG!

May 8th, 2020

Members of the Sikkel Lab in collaboration with Dr. Raquel Xavier’s lab at the University of Porto in Vairão, Portugal have been able to provide more evidence that gnathiid isopods act as vector species for bloodborne pathogens! Using molecular barcoding techniques they were able to detect traces of DNA of apicomplexan blood parasites in the blood meals of Caribbean gnathiid isopods. The paper “Molecular detection of apicomplexan blood parasites of coral reef fishes from free-living stages of ectoparasitic gnathiid isopods” is being published in the journal Parasitology Research. Click HERE to read the paper!

Congratulations to Many Gnathiid Gnation Members!

May 8th, 2020

It’s been a busy spring semester for Gnathiid Gnation! This semester saw 3 Master’s thesis defenses and 2 proposal defenses (1 dissertation, 1 thesis). On April 17th, Amber Packard successfully defended her thesis investigating the effects of parasitic gnathiid isopods on settlement stage damselfish. Then on April 24th, Jan-Alexis Berry defended his thesis on the effects of cymothoid isopods on brown chromis. Finally on May 5th, Clayton Vondriska defended his thesis where he investigated how chemical cues relate to host susceptibility to parasitic gnathiids. As for proposal defenses, Annie Savage defended her thesis proposal where she will be investigating the impacts of coral diseases on gnathiid isopods. Lastly, Matthew Nicholson defended his dissertation proposal where he will be figuring out how gnathiids fit in marine food webs. Congratulations to all these Gnathiid Gnation members!


I am a marine ecologist. I received my Ph.D. in Zoology from Oregon State University, with an emphasis on behavioral, marine, and fish ecology. My doctoral research focused on the reproductive behavior and endocrinology of garibaldi damselfish in my home-state of California. My extensive field work on this species provided the scientific basis for its protection in California coastal waters and its establishment as the official marine state fish of California. During my post-doctoral studies in the Virgin Islands and Barbados, I switched my focus to tropical reef organisms, and developed a fascination with the diel changes in activity that occur on tropical reefs, including the interactions between external parasites that infest reef fishes and the cleaning organisms that consume those parasites. Understanding the symbiotic relationships involving fishes, parasites, and cleaners and the ecological consequences of those interactions is the current focus of my research program.

Although I maintain an integrative, interdisciplinary perspective, my research questions are driven primarily by observations during my extensive time in the field. I have conducted field research in a variety of places around the world, including Southern California, Mexico, Hawai’i, Australia, Panama and eastern Caribbean, Guam, the Philippines, and South Africa.

To view a short film featuring our work on day-night transitions on reefs, see Ripple.