ELEMENT STEWARDSHIP ABSTRACT

for

higgins eye

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THE NATURE CONSERVANCY

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The Nature Conservancy

Element Stewardship Abstract

For LAMPSILIS HIGGINSII

Common Name: HIGGINS EYE

Global Rank: GI

(From Parmalee 1967:67-68) "Shell oval, elliptical or rhomboid, somewhat inflated, thick heavy; anterior end rounded, posterior end bluntly pointed in the male, truncated in the female. Beaks directly forward, swollen, elevated; sculpture consists of a few, slightly looped feeble ridges. Posterior ridge rounded but distinct. Surface usually shiny marked by irregular growth lines which are more pronounced at rest periods where they become dark colored. Epidermis yellowish or olive, with faint to quite distinct green rays.

Left valve with two triangular or pyramidal, thick, erect, divergent, serrated pseudocardinal teeth; the two lateral teeth heavy, moderately thick and short, roughened. Right valve with a large, erect, massive, triangular tooth in front. Interdenturn fairly narrow; beak cavity deep. Nacre silvery-white, often tinged with pink; iridescent posteriorly." See illustration in Parmalee (1967).

Individuals occurring within 1,000 linear meters of each other, with no barrier to fish passage, are considered one occurrence.

"A" Rank:

Manageable threats, and a population extending over 1,000 meters of stream where an

experienced searcher can locate 10+ live specimens per/hr. including young individuals.

More threats, and a population extending over 1,000 meters of stream where an experienced

searcher can locate between 5 and 10 live specimens per hour including young individuals.

"C" Rank:

More difficult-to-control threats and a population extending over less than 1,000 rn of stream

where between 5 and 10 live specimens can be found in an hour of handpicking.

Greater, more difficult-to-control threats and fewer than 5 live specimens can be found in a hour

of handpicking.

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This species has been confused with LAMPSILIS ABRUPTA from the Ohio River System. Higgin's eye has lower umbo and a lighter periostracum (Havlik, 198 1).

11. STEWARDSHIP SUMMARY

Refer to General Freshwater Mussel ESA.

111. NATURAL HISTORY

This species is restricted to the upper Mississippi River and a few tributaries. Historically it ranged from Louisiana, Mississippi, to Prescott Wisconsin. Once found in 10% of the tributaries in this range, it now occurs only in the lower reaches of the Wisconsin River and the St. Croix River (Havlik, 198 1).

Found in substrates of mud with a mixture of gravel and stones. Prefers rapidly flowing water (USFWS, 1982).

The exact breeding season is unknown but the closely related LAMPSILIS ABRUPTA is gravid from September to June (Ortmann, 1919). Sexual maturity is reached in 6-12 years, an individual may live up to 50 years. The host fishes are unknown but may be the Sauger and Freshwater Drum (Surber, 1913; Stem, 1982). Refer to General Freshwater Mussel ESA for additional general biology/ecology information.

IV. CONDITION

Fuller (1978) suggested that overfishing may be at least in part responsible for the decline of this species. Overharvest, pollution, dredging of waterways, sand and gravel mining in rivers, siltation, dam and levee construction, channel and navigation maintenance activities and stream channelization are also thought to have contributed to the decline of this species.

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The species has declined from approximately 45% of its original range.

This species has received more conservation aid than any other mussel and is the subject of a federal recovery plan. It has been transplanted with at least initial success. Since the inception of the recovery plan, additional populations have been discovered, some containing numerous individuals. It has been suggested by some workers that it be delisted from the endangered status. Because of this attention, this species may be a good candidate for man-mediated recovery and conservation within its remaining range.

Refer to the General Freshwater Mussel ESA.

Oblad (1980) and Nelson (1982) reported on a relocation effort for L. HIGGINSI. That species was recovered by brail in an area scheduled for the construction of a new bridge at Moline, IL. Some 7,000 mussels were collected by divers and marked with monofilament tags and/or paint. Of these 7,000, three were individuals of L. HIGGINSI, two males and one female. All mussels were transplanted 1/4 mile upstream into the same mussel bed along a transect line. A year later, all three L. HIGGINSI were recovered alive and apparently healthy. It is unknown if the mussels have, or will, reproduce or if the fish host (unknown) is present. It is felt that at least 8-10 years of monitoring would be necessary to determine if the transplant was a success in the long term. There are no such plans to continue the project.

Stern (1982), leader of the U.S. Fish and Wildlife Higgin's Eye Recovery Plan, has outlined the project. The aims of the project are to establish a minimum of five viable, reproducing populations and to minimize environmental impacts. He defines a viable, reproducing population as one having equal or greater recruitment than mortality. Of the 17 initially potential sites, seven were suitable for transplanting. Because so little is known concerning the habitat requirements of this species, the sites were chosen in part because of associated naiads. Nelson and Freitag (1980) noted that in over 50% of the collection records, Higgin's eye was associated with 17 more common species. The ongoing project will monitor the species for 1) viable glochidia; 2) presence of host fish, believed to be the Sauger and Freshwater drum; 3) successful establishment of metamorphosed juveniles; and 4) presence of several age classes.

VI. RESEARCH

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Refer to the General Freshwater Mussel ESA.

Nelson, D. A. and T. M. Freitag. 1980. Ecology, identification and recent discoveries of Higgin's eye (LAMPSILIS HIGGINSI), Spectacle case (CUMBERLANDIA MONODONTA), and Fat pocketbook (POTAMILIS CAPAX) mussels in the upper Mississippi River. Pp. 120-148 in J. Rasmussen, ed., Proceedings of the UMRCC Symposium on the Upper Mississippi River Bivalve Molluscs. Upper Mississippi River Conservation Committee, Rock Island, IL.

Nelson, D. H. 1982. Relocation of LAMPSILIS HIGGINSI in the Upper Mississippi River. In: U.S. Army Engineer Waterways Experiment Station, C.E., Report of Freshwater Molluscs Workshop, Vicksburg, MS.

Oblad, B. R. 1980. An experiment in relocating endangered and rare naiad molluscs from a proposed bridge construction site at Sylvan Slough, Mississippi River Near Moline, IL. Pp. 211-222 in J. Rasmussen, ed., Proceedings of the UMRCC Symposium on the Upper Mississippi River Bivalve Molluscs. Upper Mississippi River Conservation Committee, Rock Island, IL.

Stern, E. M. 1982. Higgins' eye mussel recovery plan: problems and approaches. Pp. 108-113. In: U.S. Army Engineer Waterways Experimental Station, CE. "Report of Freshwater Molluscs Workshop", Vicksburg, MS.

Edition Date: 87-04-16

Edition Author: WATTERS, THOMAS G. (Ohio State University)

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