Spring Cavefish: Additional Information

References

Pflieger, William L.  The Fishes of Missouri.  Missouri Department of Conservation, 1975.

McDonald, Eugene F., Jr., and William L. Pflieger.  " The Spring Cavefish, Chologaster agassizi (Pisces: Amblyopsidae) in southeastern Missouri."  The American Midland Naturalist, vol. 102, no. 1, pp. 194-196.

Adams, Ginny L.; S. Reid Adams and Brooks M. Burr.  Progress Report Missouri Spring Cavefish Project.  Submitted to the Missouri Department of Conservation, June 2000.

Adams, Ginny L.; S. Reid Adams, Amy L. Phillips, and Brooks M. Burr.  Natural History and Habitat Utilization of the Spring Cavefish, Forbesichthys agassizi, in Southeast Missouri.  Southern Illinois University at Carbondale, Carbondale IL.  Submitted to the Missouri Department of Conservation.  June 2002.

Aley, Thomas; Catherine Aley and Philip Moss.  Declineation of the Recharge Area for the Spring Cavefish (Forbesiahthys agassizi) Springs, Scott County, Missouri, Final Report.  Ozark Underground Laboratory, contract study for the Missouri Department of Conservation, June 2000.

Newspaper Article (1980)

"Rare fish found in Scott County placed on endangered species list"
Daily Sikeston Standard (September 8, 1980)

A species of rare fish found only in north Scott County in Missouri has been placed on the endangered species list by the Missouri Conservation Commission, which fear extinction of the species.

The tiny school of fish, called Spring Cavefish (Chologaster agassizi), was discovered in 1975 by a biologist, Eugene F. McDonald of Cape Girardeau. The school is located in a small spring-fed pool at the base of a bluff in the general vicinity where new industry is being anticipated.

According to the reports, the spring begins in a small inaccessible cave in the limestone bluffs. McDonald, a former science teacher in the Illmo-Scott City school system, had studied the Southern Illinois habitats of the fish and believed that the cavefish might also be found in similar habitats in Southeast Missouri. He checked topographic maps which revealed several places where bluffs adjoined lowlands in the Benton Hills area.

W. L. Pflieger, senior biologist in the Research Department of the Missouri Conservation Commission, who, along with McDonald, had not elaborated on the find for fear the public would further endanger the fish, said Friday, "The survival of this population of fishes is important for several reasons."

"First of all, this is the only known population of the spring cavefish west of the Mississippi River. This species is otherwish known only from a restricted area in Illinois, where it is an endangered or threatened species, and Tennessee and Kentucky, where it is more common."

Pflieger theorizes that the Missouri population was probably isolated from Illinois populations when the Mississippi River changed its course about 2,000 years ago, and possibly has undergone some genetic divergence.

"The spring cavefish is on the evolutionary threshold between more specialized members of its family such as the Ozark cavefish, which complete their entire life cycle in caves and typical surface-dwelling species that rarely enter caves," Pflieger said.

Scientific studies shown that until fairly recent geologic times, the Illinois and Missouri bluff line was continuous with the Mississippi River flowing southwestward into the broad lowland between the Benton Hills and the Ozark Uplands to the north. Then the river was diverted through the narrow gap between Benton Hills and Shawnee Hills of Southern Illinois, also isolating the tiny fish.

Adult spring cavefish reach a maximum of three inches. The fish is subterranean, emerging at dusk and usually retreating underground an hour or two before dawn. It is pigmented and has small, fully developed eyes that appear functional but serve only to distinguish light and darkness. Two other species of cavefish found in Missouri differ from the spring cavefish in that they are almost colorless and have no eyes.

Collection of species of the fish in Missouri is prohibited without a special permit. Efforts are being made to protect and restore the habitat which is privately owned.

Update Letter from Missouri Department of Conservation (1996)

After the great floods of 1993 and 1995, there was interest in whether the floods had affected the spring cavefish. MDC studied the sites and their report is in the following letter. Please note that the cavefish sites actually are on land owned by a local farmer, John Pobst, and not on Port property as described in the letter.

From:  Missouri Department of Conservation
Headquarters, 2901 West Truman Blvd, P. O. Box 180, Jefferson City MO 65102-0180
Telephone: 573-751-4115 - Missouri Relay Center: 1-800-735-2966 (TDD)

July 29, 1996 to Southeast Missouri Port Authority:

I want to thank you for your cooperation in our recent survey of the spring cavefish population at Cape LaCroix Bluffs. We were able to survey the population on Southeast Missouri Port Authority property. We also hope to do more at the site in the future.

As you may know, several springs in the LaCroix Bluffs are used by spring cavefish (Chologaster agassizi). The fish is listed in this state as Endangered because it is known only from this one site west of the Mississippi River. It was first found in this location in 1976. It is believed that about two-thousand years ago the Mississippi River shifted its course to a narrow gap between the Benton and Shawnee Hills of southern Illinois, isolating this population west of the river.

The majority of the spring cavefish's present day range in in swamps, springs and caves in south-central Tennessee, western Kentucky, and southern Illinois. Because of its unique location the Cape LaCroix Bluffs site is of great interest to us.

In our recent survey, we counted three spring cavefish in one of the springs. They ranged in size from 3/4 to 1-1/2 inches long. A very small fish, it only reaches about 3-1/4 inches in total length. The spring cavefish is essentially blind and is thought to feed by touch. It may spend the late Spring of the year on or near the surface when water is higher. In late Summer or early Fall it may move back into small cave/spring openings and prepare to spawn. Sometime between January and April a few females from the population spawn and then move out to the surface to feed. It is thought that only a few breed each year and that populations sizes are very small.

You may have noticed, there is much supposition in describing the species and its range. Little is known of the species and even less of the apparently isolated population on Port Authority property. We are very interested in the fish and hope to do more at the site in the future.

Again, than you for your cooperation. I will contact you before any future visits are made to the site. Please feel free to call or write if I can be of service to you.

(signed) Kenneth B. Lister, Assistant Natural History Biologist

Adams Study (2002)

In June 2002 the results of an extensive study of the blind spring cavefish were published by Ginny Adams, Reid Adams, Amy Phillips, and Brooks Burr of the Southern Illinois University at Carbondale (IL).  Submitted to the Missouri Department of Conservation, the study was titled "Natural History and Habitat Utilization of the Spring Cavefish, Forbesichthys agassizi, in Southeast Missouri."

Selected excerpts from the section "Conservation and Management" address the status of the cavefish populations and factors to be considered in the nearby development of Semo Port:

Several surveys have been conducted over the previous 20 years to monitor the populations; however, this was the first study to document abundance, both spatially within springs and temporally, using a repeatable, quantitative method (page 52).

Overall, as noted in the Executive Summary, "Spring cavefish in Missouri appear to be currently stable based on data collected during this study and comparison with historical information."  The study found the East Spring population is "currently stable" but the West Spring population was lower than previously reported.  Monitoring was recommended using specified methods.

It is imperative that future managers preserve the integrity of the spring openings to allow movement of cavefish between surface and subterranean environments (page 53).

Concern was noted that sedimentation does not block the openings between surface and underground habitats.

Most of the changes in physical habitat that have occurred since McDonald discovered the population appear to be beneficial to the cavefish.  The main habitat change has been the natural progression to a more swamp-like habitat around the spring runs (personal communication McDonald and Pflieger).  Although no historical descriptions of the site exist prior to construction of the agricultural fields, we surmise the original habitat was similar to that at LaRue-Pine Hills, Illinois.  Springs along the base of Benton Hills likely drained into a large swamp and cavefish would have had access to a variety of habitat types.  Although the current swamp habitat is still restricted due to the presence of the drainage ditch and agricultural fields, we were able to discern obvious advantages.  Presence of slack-water downstream from the Spring Head appears to increase recruitment of young-of-year.  These areas provide suitable habitat for growth and refuge from predation by adults (page 54).

We suggest that no major modification to the spring run or drainage ditch be made in the near future.  Instead, allowing the springs to return to a natural state independent of human modification should be considered.  Any large-scale alterations may threaten the current spring run habitat and result in a loss of larval habitat.  Managers could improve habitat by increasing the size of the buffer zone between the spring and agricultural fields.  Only a small tree-line buffers the springs from the agricultural field.  At this time, much of the recharge area for the springs lies within areas that have either been developed for roads/railways or for farming.  The best case scenario would be purchase of the land containing the springs and adjacent farmland.  Returning the springs and swamp to the state they were in, even 50 years ago would help to insure long term stability (pages 54-55).