MDC biologists document endangered grotto sculpin nest sites

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PERRYVILLE, Mo. – Missouri Department of Conservation (MDC) biologists are documenting reproduction of the endangered grotto sculpin in Perry County caves. The grotto sculpin is a small cave fish that is only found in Perry County. It is also unique because the species seems to be currently evolving. They have varying levels of pigment, and some have eyes while others don’t, as the species adapts to cave conditions. MDC has researched the rare fish for well over a decade, but the current research project is focused on assessing population numbers and status, which includes reproduction.

“We’re very excited to have recently identified nesting activity of the grotto sculpin,” said Jason Crites, MDC fisheries management biologist.  

Crites leads habitat work and research focused on the cave system that runs through Perry County, the county with the most caves in Missouri. Crites, based out of MDC’s Southeast Regional Office in Cape Girardeau, collaborates with a team of research biologists located at MDC’s Big Rivers and Wetlands Field Station to conduct surveys of cave-dwelling species.

During a routine seining (fish netting) effort, two resource technicians on the team, Sindupa De Silva and Wes Sleeper, noticed a glob of eggs attached to the bottom of a large rock overhang. Near the rock, under the nest, was a lone grotto sculpin, seemingly guarding the eggs. The team noted the significance of the placement of eggs, hanging from the bottom of the rock (see video of grotto sculpin eggs). This technique shelters the eggs from sediment as it settles through the cave. They also observed more grotto sculpin within close proximity to other egg masses in two more nearby caves, with the eggs similarly sheltered. 

“They weren’t sure if the eggs were grotto sculpin eggs at first, or from some other animal,” Crites said. “But after looking through the research on grotto sculpin mating seasons and noting that we observed pregnant females in early March, we’ve determined these are in fact grotto sculpin eggs, being guarded by the parents.”

Crites said this is significant because nest sites of these endangered fish have not been documented before. Young of the year fish have been documented in the past and, due to the size and timing of these previous captures, it was presumed spawning occurred in winter months through back calculations of growth.  This is the first time reproduction of these endangered fish is documented deep within the caves. 

“Of all the places in the world, grotto sculpin are only known to live here in Perry County,” Crites said. “This is very exciting as we learn more about these fish, what their needs are and how we can protect them.”

In total, the team found eleven nests and several mating pairs of grotto sculpin. In another cave, only pregnant females were found, meaning the timing of the reproduction process for this species could be spread out over several weeks.

Crites said there are several things people can do to help protect this fish, which in turn, will improve the quality of the area’s water resources.

“If we can keep things tidy above ground, in regard to chemical disposal, litter and clean land management, that will help guarantee the survival of the grotto sculpin,” he said, noting the Perry County community has made great strides in cleaning sink holes and other efforts over several years.

“Conserving habitat for wildlife species almost always plays into conserving conditions for humans as well,” Crites said. “Clean water for the sculpin, means clean water for us, too.”

More information about caves in Missouri and the grotto sculpin can be found at