Fish Community Information
The fishes of the Headwaters Diversion Basin have been sampled extensively with seines and electrofishing equipment since 1940. Well distributed collection data are available from 85 seine sites (Pflieger et al. 1981 and McCord 1985), 4 private collection sites (MDC Natural History data base) and 17 electrofishing sites (Fisheries District). Site information and species specific site occurrences were tabulated and mapped (Tables 1-B, 2-B and Figure Bc01, contact authors for Appendix B information). Sample site number and letter designations were assigned by Fisheries District staff and are not related to the five digit site code used by MDC Fisheries Research staff. Stream orders and river mile distances were meticulously determined by Fisheries District staff and do not always agree with MDC Fisheries Research computer records.
Seine samples, based on purpose, techniques, methods and gear specifications described by Pflieger (1991), currently provide the qualitative and quantitative indicators that can best define entire fish communities. The seine data were organized by families of fishes. However, electrofishing samples based on boat-mounted DC equipment with a minimum station length of two miles and three hours of gear time, emphasized the collection of species which could have some angling value. No attempt was made to collect nektonic or benthic fish species. Electrofishing data were organized by groups of fishes which might generate similar angling interests or share similar management concerns.
The Headwaters Diversion Basin is contained within the Ozark-Southeast Division of the Ozark Faunal Region. This division contains no unique fish species and is actually characterized by combinations of peripherally distributed species found in seven adjacent divisions representing three faunal regions (Pflieger 1989). Consequently, the small basin supports a particularly diverse assemblage of fishes; 19 families and 113 species have been identified in seine and electrofishing collections (Table Bc01).
The number of species appearing in seine hauls has steadily increased since the 1940 sampling efforts where only 69 species were recorded from 11 sites. By the 1980's, 94 species were identified at 85 sites. The extirpated pallid shiner (Notropis amnis) and the watch-listed pugnose minnow (Opsodoedus emiliae) are the only species that have not appeared in post-1940 collections. Four low-density species that appeared in extensive sampling efforts (63 sites) during the 1960's and 1970's but did not appear in the 1980's collections are: blacktail shiner (Cyprinella venustus), bluntnose darter (Etheostoma chlorosomum), stippled darter (Etheostoma punctulatum) and blackstripe topminnow (Fundulus notatus). The blacktail shiner and bluntnose darter are Lowland, turbid water species which no longer have easy access into the basin. The stippled darter is a disjunct species with a distribution typically limited to the west side of the Ozarks; and, the blackstripe topminnow is another Lowland species that rarely occurs in association with the blackspotted topminnow (Fundulus olivaceus), which is the most frequently occurring fish in the basin.
The apparent increase in species richness from 69 to 94 species over a period of 50 years is probably attributable to improved sampling methods and skills by more knowledgeable collectors. It is doubtful that habitat and channel conditions could have improved in the last 50 years to allow species diversity to expand by 25 new species. It is encouraging to note that the basin appears to have lost only two species since 1940.
The composition of subbasin fish communities are not similar, which accounts for the variable distribution and frequency of occurrence of species within the basin. The Castor River, Crooked Creek, Whitewater River and the Diversion Channel subbasins share only 22 of the 92 species identified in seine hauls (Table Bc02). Even the Castor River, Crooked Creek and the Whitewater River drainages, which provide adjacent and similar channel elements for longitudinal species succession, share only 45 species. Apparently, longitudinal species succession is not a factor in the homogeneous habitats found in the Diversion Channel, which may account for the reduced species diversity in the lower part of the basin. No single species is the most frequently occurring fish in all subbasins (Table Bc02). The blackspotted topminnow is probably the most ubiquitous species in the basin and appears at nearly 90 percent of all sample sites on the Castor and Whitewater rivers. However, depending on the subbasin, redfin shiner (Lythrurus umbratilis), striped shiner (Luxilus chrysocephalus), bleeding shiner (Luxilus zonatus), bigeye chub (Notropis boops) and longear sunfish (Lepomis megalotis) are widely distributed species than can be present at more than 75 percent of the sites in some drainages. At least 12 other common species can be expected to occur at 50 percent of the sites in the basin.
Due to the unique subbasin species distributions, management considerations, particularly those relating to nektonic and benthic fishes, may need to focus on specific localities within the basin and not necessarily on particular species throughout the basin. Site management may produce more consequence than species management.
The relative abundance within subbasin fish communities, especially at the family level, are quite similar (Table Bc02). Castor River, Crooked Creek and Whitewater River have nearly identical minnow, sunfish and darter components (descending order of dominance) that account for about 90 percent of the community densities. The dominant order of component densities in the more sluggish Diversion Channel, however, is sunfish, darter and minnow which total about 70 percent of the community numbers. Variation in the order of abundance of particular species within a family is apparently related to subbasins. The Ozark minnow (Notropis nubilus), bluntnose minnow (Pimephales notatus) and bleeding shiner are probably the three most abundant species in the basin and are definitely the most abundant fish in the Castor and Whitewater subbasins. The bluntnose minnow is also the most abundant species in Crooked Creek, followed by the speckled darter (Etheostoma stigmaeum) and largescale stoneroller (Campostoma oligolepis) which are absent or minor components in the other subbasins. The Diversion Channel community is dominated by the cypress darter (Etheostoma proeliare), redfin shiner and pirate perch (Aphredoderus sayanus), which occur in low numbers in the other subbasins. Longear sunfish occur at moderate densities throughout the basin and bluegill (Lepomis macrochirus) are important only in the Diversion Channel.
Benthic and nektonic species are probably quantified better by seine samples than larger, longer-lived fish species, especially those catfish, sunfish and sucker species that attract most of the angling and resource management attention. Seine data, however, can indicate the presence, possible nursery locations and maybe even the relative abundance of the juveniles of large species that seldom appear in boat-mounted electrofishing collections.
In 1981, to provide some historical inferences for site-specific occurrences, Bill Pflieger informally and quite subjectively designated 43 species of fish as "intolerant" -- the first species to be affected by the degradation of stream habitats and channels. The list of intolerant species includes fairly diverse groups of large, nektonic and benthic fishes which typically occupy a wide range of stream habitats in particular faunal regions (Table 16). Some intolerant species should be expected to occupy healthy stream sites, regardless of habitat type, because of high relative abundances (uniqueness indices), specific distribution patterns (faunal regions) and associations with general fish habitat guilds (water column location). Therefore, the presence, absence or changes in composition of intolerant species might be an indicator of general stream health.
Twenty-nine intolerant species are known to occur in the Headwater Diversion Basin and, except for the rare blacknose shiner and extirpated pallid shiner, all have been collected since 1984. The distribution and occurrence of intolerant species throughout the basin is so high (88% of all seine sites, 96% in some tributaries) that the number of intolerant species present, relative to the total number of species captured, at any one site may be a potential parameter for assessing changes in stream health.
In the Headwater Diversion Basin, the expected number of intolerant species is about 30 percent of all species for seine samples greater than 10 total species. The expected proportion of intolerant species drops to about 20 percent for samples collected in habitats containing less than 10 total species. The 20 and 30 percent intolerant species proportions might be used as standards to monitor and compare general stream condition or to evaluate current site conditions.
It is possible, however, that the expected number of intolerant species is actually a 30 percent subsample of the total species available in the basin (29 intolerant species/94 seine sampled species = 31 percent) and has no significant bearing on a species tolerance of habitat conditions. The overall excellence of stream habitats and water quality throughout the basin might be entirely responsible for the wide distribution and frequent occurrence of intolerant species. More sample information from degraded or disturbed sites (within and outside of the basin) is needed to verify an intolerant species/total species relationship; or perhaps, an intolerant species/habitat quality association. If a simple relationship or association does exist, then a seine will become an important management tool.
Boat-mounted electrofishing efforts, directed at only large or easily dipped species, (Table Bco3) resulted in the collection of six families and 18 additional species. Ten of the additional species are members of the gar, herring, sea bass, paddlefish, eel and drum families. Four long-fin sucker species (e.g. buffaloes), walleye (Stizostedion vitreum), sauger (S. canadense), black crappie (Pomoxis nigromaculatus) and a single goldfish (Carassius auratus) were collected exclusively with electrofishing gear. Species composition appears to be a useful parameter which tends to be independent of electrofishing variables. The standard deviation of replicate site samples is small and most of the variation is accountable in the gizzard shad (Dorosoma cepedianum) portion of the sample. The standard deviations of site relative densities (electrofishing catch rate), however, are quite large and are probably caused by temporal and physical variables.
Basin fish communities are good examples of longitudinal succession . Species diversity decreases with increased elevations and gradient which promotes some species such as longear sunfish, shadow bass (Ambloplites ariommus), green sunfish (Lepomis cyanellus), smallmouth bass (Micropterus dolomieu) and the short-fin suckers (e.g. redhorse spp.) to dominance in the upper watersheds; while bluegill, spotted bass (Micropterus punctatus), crappies and the long-fin suckers tend to dominate the communities lower in the watersheds.
Spotted bass is the predominant black bass (85 to 90% of EF samples) throughout most of the basin. Spotted bass begin to avoid gradients steeper than 12 ft/mile and are totally replaced by smallmouth bass (80 to 90%) in the upper watersheds at gradients greater than 14 ft/mile. The composition of largemouth bass (Micropterus salmoides) (6 to 10%) is fairly uniform throughout the basin and appears to be independent of elevation and gradient. A single significant concentration (99%) of largemouth bass occurs at the confluence of the Diversion Channel and Mississippi River. Further upstream in the Diversion Channel (10 to 20 miles), juvenile spotted bass dominate the black bass component. The concentration of juvenile spotted bass in the altered Diversion Channel, however, is probably a result of flood displaced fish trapped downstream of the Blockhole grade control structure, which functions as a 10-ft high barrier (falls) during normal flows.
The most abundant large species in the Castor River, Crooked Creek and Whitewater River subbasins are longear sunfish, golden redhorse (Moxostoma erythurum), gizzard shad and green sunfish, which occur in relatively similar densities (Table Bc03). The mouth of the Diversion Channel is dominated by gizzard shad, common carp (Cyprinus carpio), largemouth bass and bluegill.
Again, due to the differences in subbasin species distributions and densities, management considerations and activities, especially those targeting sport and commercial species, may need to concentrate on specific stream locations or reaches and not necessarily on the entire basin or even entire subbasins.
The length frequency distributions of a species between and within subbasin are quite similar (Table 7-B in Appendix B). The combined total of all subbasin length data (weighted) probably best describes the size structure characteristics of the basin fishes (Table 18), based on standard lengths, in inches, which are:
|Species||(PSD) Stock||(RSD) Quality||Preferred||Memorable|
|SM and SP Bass||7||11||14||17|
|Bluegill and Longear||3||6||8||10|
|CCF and FCF Catfish||11||16||24||28|
The basin fish community offers some pleasant angling and gigging opportunities. The recruitment of fishes to stock-size is good and presents no immediate management problems concerning annual production or early mortalities. For most species, quality-size recruitment can range from adequate to excellent and some recruitment to preferred-size is occurring throughout the basin.
The spotted and smallmouth bass PSD and RSD values are limited by natural and angling mortalities that have not yet been partitioned by a creel survey. Slow growth (11 inches long at age 4 and 14 inches long at age 5+), mediocre body condition (Wr approximately 80) and crowded conditions (83 percent of the population is concentrated between 6 and 10 inches in length) are factors which may be limiting longevity and recruitment to larger sizes. Recruitment to stock-size is definitely not a problem. Angling mortality (legal and illegal) could be responsible for much of the accelerated mortality of bass longer than 11 inches. Recruitment of spotted bass to quality-size should be a management concern. Both types of mortality could be managed with similar or different harvest regulations, depending on angling pressure and the known magnitude of the natural and angling mortalities. Accurate creel information would be needed to formulate proper harvest regulations.
The largemouth bass size structure is considerably better than the other black bass species. Body condition and growth are also better. Because largemouth bass densities are low, negative population responses to spotted bass management efforts should not become an issue or consequence in most of the basin. An exception is the extreme lower reaches of the Diversion Channel where largemouth bass management concerns (because of high densities) should definitely take precedence over the other black bass species.
Shadow bass size structures throughout the basin include a high proportion of fish longer than seven inches. Preferred-size fish, however, are fairly uncommon. Growth rates are above average (Carlander, 1977), densities are low and longevity is evident, which suggests that the large difference between PSD and RSD parameters is probably related to angler exploitation. Harvest restrictions could regulate angler exploitation if overfishing or high angler use can be demonstrated.
The dense, slow growing subbasin populations of longear sunfish produce few quality-size fish (6 inches long) and virtually no fish longer than eight inches. Most longear sunfish do not live long enough (age 6) to reach six inches long. Unless it can be demonstrated that anglers are willing to harvest abundant and easily caught small panfish, the contributions of the longear sunfish populations to the basin are probably more related to the ecology of the stream system than to providing angling opportunity.
Bluegill are providing an excellent fishery in the lower Diversion Channel subbasin. An outstanding size structure, which includes some fish eight inches long, and growth rates that produce fish six inches long in three years, are characteristic of the lower basin where competition with other sunfishes is minimal. Elsewhere in the basin, a high proportion of bluegill reach six inches in length (and sometimes 8 inches), however, densities are low and the species cannot be expected to contribute significant numbers to the creel.
Channel and flathead catfish size structures are represented by excellent proportions of fish 16 and 24 inches long. Most of the catfish captured by standard electrofishing and one-inch mesh hoopnets in all District 11 basins have reached stock-size (11 inches long) and few juvenile catfish, of any species, are ever observed.
Most captured carp, throughout the basin, are typically more than 16 inches long and carp less than 11 inches long have never been sampled anywhere in the basin. The Whitewater River subbasin, in particular, produces large carp -- where individuals approaching memorable size (26 inches long) are common.
Freshwater drum, in the Castor River, is the only species that tends to have a size structure influenced by position in the watershed. Larger individuals are more frequently captured (electrofishing) in the steeper gradients of the upper watershed. Improved gear efficiency in the clearer and shallower pools may be a factor. Preferred-size fish (15 inches long) are quite common and memorable-size fish (20 inches long) are occasionally caught.
The literature does not provide size parameters for short-fin suckers. The golden redhorse comprises about 11 percent of the numbers of all basin fishes and probably more than 60 percent of the total biomass. Therefore, provisional stock-, quality- and preferred-size length values of 8, 12 and 14 inches have assigned to this important species to allow subbasin and eventually interbasin population comparisons. The lengths of the size parameters were selected from inflections on length frequency distributions representing over 15,000 golden redhorse from four adjacent river basins.
Golden redhorse occur at remarkably similar densities in the Castor River, Whitewater River and Crooked Creek subbasins; however, the subbasin size structures of golden redhorse are considerably different. The Whitewater River typically produces large fish and Crooked Creek produces particularly small fish. The size of the Castor River fish appears to be intermediate.The Whitewater River watershed is probably the most fertile and Crooked Creek definitely has the least fertile watershed in the basin. Unfortunately, comparative age and growth information is not yet available. Possibly more significant is the fact that Crooked Creek is the clearest stream and Whitewater River is the most turbid stream in the basin. Gigging exploitation on Crooked Creek or under-utilization by anglers on Whitewater River may be factors that are influencing the size structures of golden redhorse populations.
Age and Growth
A basin summary of available age and growth data can provide some useful baseline information regarding growth expectations and limits (Table 19). However, all of the basin growth information that is currently available (including the 4,000 aged and back-calculated fish) does not identify or even suggest causes for variation in growth between and within subbasins. In no instances have growth patterns conformed to correlations that might be expected with the measurable independent variable of population densities, body condition and size distributions. Similar data from the St. Francis and Black River basins also appear to be unrelated. It is not certain, at this time, if the data are actually unrelated, or if the data are not precise enough to produce expected correlations.
Forage densities and forage availability, which are certainly related to watershed fertility and primary productivity, are probably the primary factors responsible for variation in the growth rate of basin fishes. However, no effort has been made and no attempts are planned to routinely quantify the extremely complex forage relationships associated with stream ecosystems. It is doubtful, therefore, if even the most rudimentary factors that dictate growth in stream communities will be fully understood soon. This can, indeed, become a resource management handicap, for example, when factors responsible for wide year-class fluctuations in the local growth rate of a particular species cannot be identified. Also, relying on anticipated changes in growth to help assess or evaluate a stream management practice may not be the proper approach.
The Missouri State-Wide Angler Survey (Weithman, 1991) is the only source of creel information for the basin. Accurate estimates of total angler pressure, catch and harvest are not likely obtainable in small, low-use basins where the number of anglers interviewed is low (403 anglers during the six-year survey period). However, the raw survey data which partitions angler species preference, effort, success and satisfaction can provide some inferences that describe angler utilization of the fishery resource.
Two of the more popular Headwater Diversion Basin streams are reported in the State-Wide Angler Survey: The smaller (4E, 5E, 6E), rural, free flowing, clear, Castor River in the upper basin; and, the larger (6E and 7E), urban, channelized, turbid, Diversion Channel in the lower basin. Differences in angler effort and success are quite apparent between the two contrasting streams and fish communities (Tables Bc04 and Bc05).
Most of the angling effort on both streams is nonspecific ("Anything"). Species-specific anglers seek mostly black bass, catfish and sunfish on the Castor River; while carp, crappie and catfish dominate the effort on the Diversion Channel. Catfish is the only species that shared a relatively high common effort on both streams.
Catfish angler catch rates are higher on the Castor River than on the Diversion Channel and bass angler catch rates are higher on the Diversion Channel. The total overall angler catch and harvest rates on the Castor River appear to be much higher than on the Diversion Channel. The higher overall success on the Castor River, however, is probably inflated by the abundance of longear sunfish available to the nonspecific angler. Also, the less abundant crappie probably deflates the success of the Diversion Channel nonspecific angler.
Anglers certainly rate the quality of fishing on the Castor River as being considerably better than the Diversion Channel. Catfish are the only species that anglers on the Castor River rate below 5.0 (on a 10-point scale where 10 is the best). Diversion Channel anglers rate all species, except carp, below 5.0. It is important to note that catfish anglers are the least satisfied anglers on both streams, and the large contingent of crappie anglers on the Diversion Channel rate the fishery as poor (2.6).
Anglers on both streams release a significant portion of their total catch (Castor River 49%; Diversion Channel 59%). Bass anglers on both streams release about four out of five bass caught and Diversion Channel crappie anglers release one out of three crappie caught.
The species composition of the total catch generally parallels angler preference effort. Exceptions are a high proportion of sunfish in the total catch on both streams, and a low proportion of catfish in the total Castor River catch. About 90 percent of the total Castor River catch is represented by (in descending order): sunfish, bass, shadow bass and catfish. Ninety percent of the total Diversion Channel catch is composed of: crappie, catfish, carp, sunfish and freshwater drum.
Threatened and Endangered Species
No federally listed (USFWS Endangered Species Act) threatened or endangered fish occur in the basin. The state of Missouri, however, lists the status of 10 basin fishes as either Rare (4 species), Extirpated (1 species) or Watch List (5 species). The extirpated pallid shiner (Notropis amnis) and the watch listed pugnose minnow (Opsodoedus emiliae) have not been collected in the basin since 1941. The other eight threatened species have been sampled or identified more recently (Table Bc06).
None of the threatened species are unique to the Ozark-Southeast faunal community, which is the dominant Division in the Headwaters Diversion Basin. Parts of three bordering faunal divisions are responsible for the diversity and distribution of the threatened species. The lake chubsucker (Erimyzon sucetta), Eastern slim minnow (Pimephales tenellus pariceps), scaly sand darter (Ammocrypta vivax), flier (Centrarchus macropterus), American brook lamprey (Lamperta appendix), pugnose minnow and pallid shiner are all largely confined to the Lowland-Flowing Water Division. The silverjaw minnow (Notropis buccatus) is definitely restricted to the Ozark-Mississippi 1 Subdivision; the blacknose shiner (Notropis heterolepis) is associated with the Prairie-Lower Missouri Division; and the paddlefish (Polyodon spathula) migrates out of the Big River-Overflow Waters Division.
The distribution of threatened fish species within the basin is significant. Twenty-one of the 27 sample sites where 8 of the 10 threatened fish species have been found are concentrated in two specific stream reaches on the Castor and Whitewater Rivers (see Unique Habitat section). The Castor River reach also contains all five of the state or federal threatened naiad species that have been collected in the basin. Both of these particular stream reaches are located within the peripheral edges of the overlapping Ozark-Southeast and the Lowland-Flowing Water Faunal Divisions. The Whitewater River reach may also include some Ozark-Mississippi 1 Subdivision influence, as evidenced by the fairly common occurrence and abundance of the silverjaw minnow. Basin management decisions and efforts will certainly need to emphasize these two river reaches when considering the protection of threatened species and associated habitats.
The aquatic invertebrate community has been sporadically surveyed by various MDC collectors using specialized sampling methods and reporting techniques. Survey results are in the MDC Natural Heritage data base.
Thirty-seven species of naiades were collected in the basin by Ronald Oesch and Al Buchanan between 1978 and 1983 (Table Bc07). Five naiad species are state listed as rare or endangered: elephant ear (Elliptio dilatata), Western fanshell (Cyprogenia aberti), Southern hickorynut (Obovaria jacksoniana), snuffbox (Epioblasma triquetra) and Curtis pearlymussel (Epioblasma f. curtisi). The Western fanshell and Curtis pearlymussel also have a federally endangered status. All five of the threatened naiad species have been collected in a reach of the Castor River between RM 1 and RM 12. The Southern hickorynut has also been collected in Crooked Creek at RM 21 and at an unknown site on the Whitewater River.
The mucket (Actinonaias l. carinata) is a commercially important naiad species that is quite common throughout the basin and comprises about 31 percent of the total species composition. The buckhorn (Tritogonia verrucosa), black sandshell (Ligumia recta) and yellow sandshell (Lampsilis teres) are also commercially important species, but occur only in low densities (usually <1% of the total species composition). The lady finger (Elliptio dilatatus), which has no commercial value, is the most commonly occurring species in the basin and accounts for about 46 percent of the naiad species composition.
Eight species of crayfish were collected in the basin by William Pflieger between 1984 and 1987 (Table Bc08). Crayfish abundance is definitely dominated by Ozark Faunal Region species; however, it is the presence of the Lowland species that is responsible for the diversity of the crayfish community.
One hundred-twenty three benthic taxa were identified in the basin by Frank Ryck and Linden Trail during 1975 and 1976. The mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), aquatic beetles (Coleoptera) and midges (Diptera) account for about 87 percent of the benthic abundance and 76 percent of the taxa diversity (Table Bc09). The composition and diversity of the benthic community are indicative of good water quality.
The basin contains a diverse wetland fauna, which, again, is indicative of the broad spectrum of habitats that are available in the basin. Recent guidelines for managing wetland resources (MDC 1993c) identify 87 species of fishes, naiades and crayfishes that tend to inhabit wetlands during part of their life cycle. Sixty-three of these designated wetland species have been collected in the basin (Table Bc10).
Opportunities to take advantage of the many remnant wetland populations may be present in the lower basin, even though specific information related to the management and habitat requirements of wetland species is limited. Acquisition of low lying areas (particularly the old Dark Cypress Swamp) and then the creation of frequently flooded slackwaters with numerous mainstream channel connections would do much to replace some of the wetland habitats lost to agricultural land improvements.
Fish Introductions and Stockings
There are no known records of any authorized resource agency introduction or supplemental stocking of exotic or native fishes in the streams of the basin. However, lentic water overflow, bait bucket distribution and immigration of extrinsic fishes do occur, as evidenced by the unusual presence of redear sunfish (Lepomis microlophus), fathead minnow (Pimephales promelas), goldfish and bighead carp (Hypophthalmichthys nobilis) in an occasional fish sample.
The only commercial fishing opportunity in the basin is limited to 0.6 mile of overflow flood water near the mouth of the Diversion Channel (less than 150 acres). Adequate flood conditions (approximately 36 ft on the Cape Girardeau gage), which allow legal and effective deployment of commercial gear, usually only last about two weeks each year. The commercial harvest of fish in the remainder of the basin is illegal and probably insignificant. Commercial fishing interest and activity on the adjacent Mississippi River in Cape Girardeau County is low and on the decline.
The 1990 Mississippi River species composition (by weight) of the reported Cape Girardeau County total commercial catch was: (in descending order) buffalo, paddlefish, carp and blue catfish. It is not likely that significant numbers of paddlefish would concentrate in the shallow overflow flood waters.
Other Management And Research Efforts
On the middle Whitewater River, McCord (1986) tried to test several proven hypotheses relating longitudinal succession of fish community structures to the variables of: habitat volume, habitat depth and physicochemical conditions. Multiple seine and backpack electrofishing samples were collected between February 1985 and February 1986. The results did not support the hypotheses and the study was inconclusive.
The Long Term Resource Monitoring Program (LTRM) established a fish component sampling site on the lower Diversion Channel at RM 0.7 in 1992. Samples are collected during three periods between June and October with gillnets, fyke nets, minnow fyke nets, hoopnets and boat-mounted electrofishing equipment. The primary information collected relates to community structure: percent composition, relative abundance, length, weight and possibly some centrarchid and ictalurid age and growth. The LTRM also monitors for the zebra mussel (Dreissena polymorpha) at this site, and may eventually add an invertebrate monitoring component.
Statewide stream fishing regulations (creel limits, size limits, methods and seasons) apply to most of the streams in the basin. Exceptions to the statewide stream regulations that refer to specific areas on the Diversion Channel are:
•3CSR 10-6.310 (2) Sport Fishing Seasons: Seasons, Limits. - Black bass may be taken throughout the year on the Diversion Channel from the mouth of the Diversion Channel at the Mississippi River to the Missouri Highway 77/25 bridge (RM 8.5).
•3CSR 10-10.725 (1) Commercial Fishing: Seasons and Methods. Commercial fishing is allowed on the Diversion Channel, only in the temporary Mississippi River overflow waters, from the mouth of the Diversion Channel at the Mississippi River to the Union Pacific Railroad bridge (RM 0.6).
No changes in fishing regulations or the establishment of special stream management areas are planned at this time