Trapping Insights: A Summer of Research in Kendall-Frost Marsh

This summer, the San Diego Bird Alliance (SDBA) embarked on a unique journey of discovery alongside University of San Diego (USD) Professor Dr. Drew Talley and USD undergraduate student Gabrielle Gaither. Together, we continued an ongoing study led by Dr. Talley to uncover the secrets of fish life within the protected waters of the Kendall-Frost Marsh Reserve. 

From June through August, our team gathered to place and recover fish traps, contributing to essential research that sheds light on the intricate ecosystems thriving in these wetlands.

A Hands-On Partnership

This collaboration between the San Diego Bird Alliance and USD exemplifies the power of partnerships in advancing conservation science. Dr. Drew Talley’s ongoing research into fish populations in Kendall-Frost Marsh has provided invaluable insights into the health and dynamics of the marsh’s aquatic life. This summer, USD’s Gabrielle Gaither joined forces with SDBA staff—Karina Ornelas, Kelcy Coleman, Cole LaVera, Cassandra Gonzalez, Stephanie Becerra, and others—to continue this important work.

“I’m so thankful we were asked by USD to help, it strengthened our bond with the marsh and really gave life to our ReWild campaign- like why are we doing all of this? Oh yeah! Look at everything that lives here. We just felt truly part of it” – Kelcy Coleman, Native Seed Library Coordinator, SDBA

Counting Fish

For weeks at a time, our team would gather during the marsh’s low tides to set minnow traps in carefully selected areas throughout the wetland landscape. Twenty-four hours later, we returned to retrieve the traps, eager to discover what lay beneath the surface.

Every day brought new discoveries and moments of camaraderie. With clipboards in hand and buckets filled with fish, our team adopted a rhythm that made even the routine tasks feel fun. One by one, we pulled the fish from the traps, announcing the species, sex, and size, while someone else scribbled the details onto a clipboard. 

“It was almost like we were singing a song,” recalls Cassandra Gonzalez, SDBA’s Volunteer Coordinator. “We’d shout out the details, and every now and then I would laugh as I realized we were starting to repeat the rhythm. It was the perfect blend of science and fun!”

Each individual was carefully documented—species like Gillichthys mirabillis, Acanthagobius flavimanu, Leptocottus armatus, Poecilia latipinna, and the most common species we found, Fundulus parvipinnis. The data we collected contributes to the bigger picture of understanding how fish use this vital habitat and the overall health of the marsh.

The Role of Fundulus

One of the key findings from our summer research was the confirmation of the high number of Fundulus fish in the traps. This result was expected, as Fundulus is known to be a significant component of the diet of the Light-footed Ridgway’s Rail, a state and federally listed endangered bird species that calls the Kendall-Frost Marsh home.

“It’s reassuring to confirm that this endangered species has reliable access to an essential part of its diet within the marsh,” says Gonzalez. By monitoring and supporting healthy Fundulus populations, we are directly contributing to the survival and recovery of the Light-footed Ridgway’s Rail.

This connection between the fish and bird populations highlights the delicate balance within the marsh’s ecosystem, underscoring the importance of continued research and conservation efforts.

Why This Study Matters

The Kendall-Frost Marsh Reserve is a critical part of the Mission Bay ecosystem, serving as a refuge for a wide range of wildlife, including fish and bird species. By studying the fish populations, we’re able to gain a deeper understanding of how interconnected the marsh is to the larger ecosystem, including the birds that rely on these fish as a food source.

This research not only informs researchers of what small bodied fish populations live in the Kendall-Frost Marsh, but also serves as a model for studying and preserving wetlands around the world. The more we learn about the marsh’s inhabitants, the better we can protect them—and the habitats they depend on.

“I think one of the most important takeaways from being in the marsh consistently was being able to observe the habitat as a whole. Yes, our main focus was the fundulus, but while we were in the water we witnessed the elegant terns’ entire breeding cycle, the impact of human disturbance in the summer, who else is seeking shelter in the vegetation,” says Kelcy, “we just learned so much”. 

The Power of Teamwork

As the summer came to a close, our team reflected on the experience with a sense of accomplishment and gratitude. Working together with passionate students like Gabrielle, guided by the expertise of Dr. Talley, and surrounded by dedicated SDBA staff, we were reminded of the power of teamwork in conservation. 

Cole LaVera reflects, “Fish sampling helped me discover an aspect of wetland ecosystems that is hard to see from the outside, and the close encounters with different wildlife was an incredible experience”. 

Each day in the field was an opportunity not only to learn but to deepen our connection with the natural world around us. “It’s these small moments—sticking your hands into a bucket to pull out a fish, laughing with your team, taking careful notes—that reminds us why we do this work,” says Cassandra Gonzalez

As we move forward, the San Diego Bird Alliance is committed to continuing this important work and expanding our research initiatives. The data collected this summer is just the beginning—there’s so much more to learn about the ecosystems thriving in our local marshes.

Stay tuned for updates on upcoming volunteer opportunities and research projects. Together, we can ensure that San Diego’s wetlands remain a safe haven for wildlife for generations to come.

Photos courtesy of Kelcy Coleman, Cassandra Gonzalez and Karina Ornelas