Section III. Fish Community Survey
Introduction
This report documents the sixth year of fish sampling efforts within three stream reaches of Coffee Creek, an indirect tributary to Lake Michigan. The study site is located within the Coffee Creek Watershed Preserve, a 167-acre natural area within Coffee Creek Center. Coffee Creek drains approximately 16 square miles of northeastern Porter County, Indiana. The creek flows north to converge with the east branch of the Little Calumet River, which ultimately flows into Lake Michigan at Burns Harbor in Portage, Indiana. Coffee Creek is a spring-fed, cold, headwater stream with a predominantly sand to gravel substrate. The creek is home to many native fish and provides suitable habitat for migratory salmonids and other lithophilous species seeking spawning grounds. Significant stream habitat improvements were made in 1999 within some of the reaches that pass through the Coffee Creek Center development. Streambed and bank restoration produced more spatial heterogeneity, created well-developed riffle-pool sequences, and provided additional spawning areas for lithophilous species, such as salmonids, while reducing erosion and sediment and sediment-attached pollutant loading. However, other reaches in the Coffee Creek Watershed Preserve remain in their non-restored form. In the short term, the annual fish community surveys document positive or negative impacts on the fish community structure resulting from streambed and bank restoration; long-term sampling of the fish community structure will detail residential and commercial development impacts within the Coffee Creek Center.
Materials and Methods
Each fall since 1997, the fish communities in three reaches of Coffee Creek within the Coffee Creek Center have been sampled. From 1997 to 2000, sampling included 200 lineal feet (70 meters) of each of the three reaches. In 2001, sampling distances were increased to 328 lineal feet (100 meters) at each reach. On October 22, 2002, three 328-foot (100-meter) reaches were again sampled within the Coffee Creek Watershed Preserve (Figure 1). Exact reach locations have varied slightly from year to year over the past six years; however, the reaches sampled in October 2002 lie in close proximity to the reach locations surveyed in previous years. Reaches 1 (White Oak) and 2 (Stream Overlook) are located within the restored section of Coffee Creek in the northern half of the project site, while Reach 3 (Shooter Ditch Confluence) is located upstream of Reaches 1 and 2 near the confluence of Shooter Ditch and Johnson Ditch with Coffee Creek (Figure 1). No portion of Reach 3 was restored. See Appendix 21 for representative photos of the reaches sampled in 2002.
A Coffelt Mark 10 backpack electrofishing unit was used to sample each of the three stream reaches with two additional staff members netting stunned fish. All stream reaches were sampled according to guidelines established in Development of Index of Biotic Integrity Expectations for the Ecoregions of Indiana I. Central Corn Belt Plain (Simon, 1991). These guidelines require that reach distance sampled be equal to at least 15 times the stream width. This length generally includes at least two riffle-pool habitat sequences (Leopold et al. 1964). Because the average width of Coffee Creek is less than 20 feet, sampling 328 feet satisfies this guideline. Sampling followed a serpentine pattern, winding across the stream channel between the two shorelines. All fish encountered were collected, measured, and identified to the species level where possible. A majority of the fish was released unharmed at each sample location. However, two vouchers of an unidentified species were preserved in 70% isopropyl alcohol and transported to the JFNew laboratory for subsequent identification.
Index of Biotic Integrity
The electrofishing data was used to calculate an Index of Biotic Integrity (IBI) at each site. Karr (1981) first developed the Index of Biotic Integrity (IBI), which Simon (1991) further modified, for use in evaluating the biological integrity of lotic, warmwater, stream-fish communities located in the Central Corn Belt Plain Ecoregion of Indiana. Karr and Dudley (1981) define biological integrity as "the ability of an aquatic ecosystem to support and maintain a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to the best natural habitats within a region".
The IBI is designed to assess biological integrity directly through 12 fish community metrics or attributes. These attributes fall into such categories as species richness and composition, trophic composition, and fish abundance and condition. After data from the sampling sites have been collected, values for the 12 metrics are compared with their corresponding expected values (Simon 1991), and a rating of 1, 3, or 5 is assigned to each metric based on whether it deviates strongly from, somewhat from, or closely approximates the expected values. The sum of these ratings gives a total IBI score for the site. The best possible IBI score is a 60.
It is important to note that Simon (1991) developed IBI expectations primarily for warmwater streams of the Central Corn Belt Plains with modifications for the East Branch of the Little Calumet River; however, Coffee Creek, being primarily spring-fed, is a coldwater stream. Temperatures during summer months seldom exceed approximately 75°F (24°C). Because fewer species typically inhabit coldwater streams (Waters, 2000), applying warmwater expectations to a coldwater stream could potentially skew IBI estimates. Despite potential difficulties, the methodology of Simon (1991) was used to calculate IBI scores for fish community collections from Coffee Creek simply because researchers have not yet developed a fish community index to estimate biological integrity in coldwater streams in Indiana. Additionally, Coffee Creek does not closely fit a typical coldwater stream profile because it contains many eurythermic (adapted to a broad temperature range) species such as darters, creek chub, and green sunfish and few stenothermic (adapted to a low, narrow temperature range) fishes like trout. Whether or not the absence of stenotherms is a natural condition is not known; because stenotherms are relatively intolerant, the absence of stenotherms may be the result of pollution, watershed disturbance, or the like. However, the total IBI score may underrate the actual biotic integrity simply because fewer species exist in coldwater systems.
Results and Discussion
A total of 424 fish representing 12 species and 6 families were collected from the three sample reaches during the 2002 Coffee Creek fish community survey (Appendix 22). For a summary of all six years of data see Appendix 23. Creek chub ( Semotilus atromaculatus ) and central stoneroller ( Campostoma anomalum ) dominated the catch accounting for 30% and 25% of the total, respectively. Hornyhead chub ( Nocomis biguttatus ), green sunfish ( Lepomis cyanellus ), and johnny darter ( Etheostoma nigrum ) were also important components of the community comprising 11%, 11%, and 8% of the community, respectively. The remainder of the fish collected listed in order of decreasing abundance are: white sucker ( Catostomus commersoni ), common shiner ( Luxilus cornutus ), northern hogsucker ( Hypentelium nigricans ), central mudminnow ( Umbra limi ), black crappie ( Pomoxis nigromaculatus ), rainbow darter ( Etheostoma caeruleum ), and grass pickerel ( Esox americanus ). The minnow family (Cyprinidae) comprised 70% of the total sample followed by the sunfish family (Centrarchidae; 12%), the sucker family (Catostomidae; 9%), and the perch family (Percidae; 8.3%). Of the 424 fish collected, 207 (49%) are classified as tolerant, while 61 (14%) are sensitive as per Simon (1991). Sensitive (intolerant) species have historically comprised 5-10% of the fish communities in Indiana streams. No state or federally listed species were collected during the survey.
Reach-to-Reach Comparison
Although some similarities in fish community exist among the three reaches sampled, stream restoration efforts may have enhanced the fish communities at the restored sites (Figure 15). Central stoneroller and creek chub dominated the fish community at the White Oak Reach (Reach 1) and the Stream Overlook Reach (Reach 2) comprising 60% and 58% of the total fish population at those reaches, respectively. The predominance of stonerollers, hornyhead chub, and johnny darters in the White Oak and Stream Overlook Reaches indicates that clean gravel and well-defined riffles are readily available in these reaches. Creek chub also dominated the fish community at the Shooter Ditch Confluence Reach (Reach 3) accounting for 29% of the population. The presence of creek chub in similar percentages in the three reaches suggests that their preferred habitat, root wads and undercut banks, are present throughout Coffee Creek. White suckers comprised only 1.7% and 3.6% of the fish communities as the White Oak and Stream Overlook Reaches, respectively, but accounted for 20% of the community at the Shooter Ditch Confluence Reach. White suckers are more tolerant to high turbidity and silt than other sucker species found in Coffee Creek, such as the northern hogsucker. In total, tolerant species such as the white sucker dominated the fish community at the Shooter Ditch Confluence Reach composing nearly 63% of the population. Conversely, the White Oak Reach possessed a fish community with only 46% tolerant individuals. Additionally, the Shooter Ditch Confluence Reach (Reach 3) supported less than half the number of fish observed in the restored reaches, Reaches 1 (White Oak) and 2 (Stream Overlook), downstream (Appendix 24). This evidence (fewer tolerant species and more fish at the sites where stream habitat restoration has occurred) suggests that the stream restoration efforts have positively influenced the fish communities the restored reaches.
Figure 15. Coffee Creek relative (percent) fish community composition
by reach. Data are shown for the dominant and some indicator species.
Table 2 shows the calculated IBI scores and corresponding integrity class for each site sampled during 2002, while Table 3 displays the Index of Biotic Integrity classification summary. (See Appendix 24 for complete IBI calculation data.) IBI values ranged from a high of 28 in the White Oak Reach (Reach 1) and the Stream Overlook Reach (Reach 2) to a low of 24 in the Shooter Ditch Confluence Reach (Reach 3). No reaches received excellent (58-60), good (48-52), fair (40-44), or very poor (<22) ratings. Coffee Creek's average IBI score of 34, which was calculated by combining the fish data from the three reach collections, placed the Coffee Creek fish community in the "Poor" integrity class. All three reaches scored poorly on the following metrics: number of salmonid species, number of sunfish species, percent carnivorous individuals, and percent deformities, eroded fins, lesions, and tumors (DELT).
| SITE (LOCATION) | IBI |
INTEGRITY CLASS |
Coffee Creek White Oak Reach (Reach 1 ) |
28 |
Poor |
Coffee Creek Stream Overlook Reach (Reach 2 ) |
28 |
Poor |
Coffee Creek Shooter Ditch Confluence Reach (Reach 3 ) |
24 |
Very Poor-Poor |
Table 2. IBI and integrity class by site using the Index of Biotic Integrity.
IBI |
INTEGRITY CLASS | ATTRIBUTES |
58-60 |
Excellent |
Comparable to the best situation without human disturbance. |
48-52 |
Good |
Species richness somewhat below expectations. |
40-44 |
Fair |
Signs of additional deterioration include loss of intolerant forms. |
28-34 |
Poor |
Dominated by omnivores, tolerant forms, and habitat generalists. |
12-22 |
Very Poor |
Few fish present. Mostly introduced or tolerant forms. |
0 |
No Fish |
Repeated sampling finds no fish. |
Table 3. Attributes of Index of Biotic Integrity classification. Source: Development of Index of
Biotic Integrity Expectations for the Ecoregions of Indiana I. Central Corn Belt Plains (Simon, 1991).
The lack of salmonid species, abundance of tolerant species, and a high percentage of fish with deformities, eroded fins, lesions, and tumors (DELT) lowered IBI scores in all three study reaches of Coffee Creek. According to Simon (1991), the presence or absence of salmonid species determines the remainder of the community's structure and function. Salmonid presence indicates the presence of permanent habitat with low environmental stress. The lack of these species might indicate that undesirable conditions such as high, unstable flows or irregular temperature gradients occur with some frequency. An abundance of tolerant species was found throughout the stream. Simon (1991) indicates that tolerant species predominate in unstable environments affected by anthropogenic stresses and temporal desiccation. Again, this points to unstable conditions that can affect survival and reproduction of sensitive species. High proportions of individuals with DELT are also indicative of environmental stress such as overcrowding, improper diet, or excessive siltation. DELT were present on four species in Coffee Creek during the 2002 sampling: creek chub, hornyhead chub, white sucker, and central mudminnow. Low water levels and prolonged periods of less than normal rainfall most likely impacted these fish species. (The following sections include a more in-depth discussion of the impact of climate on the Coffee Creek fish community.)
Year-to-Year Comparison
Making among-year IBI comparisons for this particular study is difficult. Survey methodology has varied from year-to-year. Survey methodology can affect IBI scores. Specifically, as effort increases, IBI scores may also increase since more fish are typically collected. Additionally, regardless of how much effort is spent sampling, species present in small numbers may be collected during some sampling efforts but may be missed during others. This probably occurred in the 2002 sampling when one rainbow darter and one grass pickerel were documented. Finally, climatic conditions have varied among years (Table 4). The 1998 survey likely resulted in a lower number of collected specimens due to a precipitation event that occurred the day prior to sampling. This event dumped 1.12 inches of rain on the creek and its watershed. A rain event of this magnitude can increase, at least temporarily, the turbidity of the creek. Rapidly moving, turbid water can, in turn, impair a collector's ability to see and capture fish, especially smaller ones like darters and minnows. In 2002, monthly precipitation from June throughout October was at least one inch below normal. Combined, precipitation levels were more than four and a half inches below normal for the first ten months of 2002, resulting in low water levels in Coffee Creek. Low water levels and an increase in stream temperature typically associated with low water levels stress most fish species. Sensitive and moderately tolerant species, such as salmonids cannot tolerate such environmental stresses. Given this, the lack of salmonids and other sensitive species in the 2002 survey is not surprising.
JAN |
FEB |
MAR |
APR |
MAY |
JUN |
JUL |
AUG |
SEPT |
OCT |
NOV |
DEC |
TOTAL |
|
1997 |
2.71 |
4.26 |
1.66 |
1.82 |
4.42 |
5.72 |
2.89 |
3.87 |
2.30 |
2.28 |
1.76 |
1.94 |
35.63 |
1998 |
3.9 |
1.96 |
5.48 |
4.53 |
2.54 |
4.82 |
3.66 |
4.37 |
1.65 |
2.88 |
1.82 |
2.58 |
40.19 |
1999 |
3.8 |
1.86 |
2.00 |
6.29 |
1.45 |
2.70 |
3.21 |
2.80 |
1.25 |
1.76 |
3.10 |
3.94 |
34.16 |
2000 |
1.92 |
2.19 |
1.53 |
3.84 |
3.39 |
10.04 |
2.31 |
1.87 |
3.08 |
3.00 |
2.56 |
1.14 |
36.87 |
2001 |
1.33 |
4.85 |
0.84 |
2.59 |
4.08 |
3.88 |
4.65 |
4.78 |
2.77 |
5.24 |
2.74 |
1.06 |
38.81 |
2002 |
2.57 |
1.74 |
3.37 |
5.29 |
5.37 |
1.65 |
1.31 |
2.26 |
2.75 |
2.71 |
2.03 |
-- |
31.05 |
Average |
2.11 |
1.82 |
2.93 |
3.64 |
3.85 |
4.66 |
3.82 |
3.91 |
3.68 |
3.20 |
3.56 |
2.88 |
40.06 |
Table 4. Monthly rainfall data for 1997 through 2002 as compared to average monthly rainfall in Valparaiso, Indiana. Averages are based on available weather observations taken during the years of 1971-2000. Source: Purdue Applied Meteorology Group, 2002.
Because of the comparison difficulties among years, the most relevant parameter for comparison among years is relative or percent composition of the dominant species (Figure 16). Stonerollers, which require gravel for both feeding and spawning, have increased from 4% of the population in 1997 to 25% of the population in 2002. Stream restoration efforts, including the addition of gravel and the creation of moderately stable pool-riffle sequences, appear to have enabled this pioneer, lithophilic species to colonize of Coffee Creek. The white sucker, a highly tolerant species, has declined from 36% in 1998 to 6% in 2002. The increase in lithophilic species and decrease in tolerant species suggest habitat restoration may have improved the fish community in Coffee Creek.
A slight degradation of the Coffee Creek fish community was observed in 2002. White suckers comprised 2.4% of the population in 2000. This percentage increased to 6% in 2002. The slight increase in white suckers observed in 2002 corresponds with the decrease in rainfall (climatic stress). White suckers are tolerant of extreme temperature fluctuations and high turbidity that likely existed in Coffee Creek in 2002. Likewise, green sunfish, which are tolerant of a wide range of temperature, turbidity, dissolved oxygen, and flow conditions, increased sharply in 2002. This species, which composed 11% of the 2002 fish community, was present in only small numbers in past samples (Appendix 24). Similarly, no members of the salmonid family, a sensitive taxon, were collected in 2002. High water temperature may have limited habitat availability for these species. In-stream conditions such as low flows and high water temperatures allowed green sunfish to thrive within Coffee Creek while intolerant species such as salmonids or darters relocated to more hospitable stream reaches.
In sum, the changes observed in the fish community over the past six years suggest that both stream restoration and climate have influenced the Coffee Creek fish composition. Improved habitat has allowed some species, such as the stoneroller, to increase in abundance while climatic stress during some years has limited the habitat potential for some sensitive species such as salmonids and promoted an increase of more tolerant species such as the white sucker and green sunfish.
Figure 16. Coffee Creek relative or percent fish communitycomposition by year.
Data are shown for the dominant species and for species of particular interest.
The historical and current IBI scores reflect the impact of both stream restoration and climatic stress on the Coffee Creek fish community as well (Table 5). In the restored reaches (White Oak and Stream Overlook Reaches), IBI scores increased following stream restoration in 1999. IBI scores at these sites from 1997 to 1999 fell in the very poor to poor ranges. (The 1999 Stream Overlook Reach IBI score fell between the poor and fair ranges. Scores between IBI categories are not necessarily statistically different than the scores in the adjacent ranges.) In 2000 and 2001, IBI scores at the White Oak and Stream Overlook Reaches indicate these reaches support fish communities with fair biological integrity. The increase in IBI scores from the very poor or poor range to the fair range that coincided with stream restoration suggests habitat enhancement may have played a role in the observed improvement in biological integrity at these sites.
Although no restoration projects occurred within the Shooter Ditch Confluence, IBI scores at the Shooter Ditch Confluence Reach have improved as well. From 1997 to 1999, the IBI scores at the Shooter Ditch Confluence Reach indicate that biological integrity at this site was poor. In 2000, the IBI score placed the reach's biological integrity between the poor and fair ranges. Again because this score falls between two ranges, it is not statistically different than scores in the two adjacent ranges. However, 2001 IBI score places the reach's biological integrity decidedly in the fair range.
The improvement in IBI score observed at the Shooter Ditch Confluence Reach from 1997-1999 to 2001 may be the result of two factors. First, stream habitat improvements made downstream of the Shooter Ditch Confluence Reach may be affecting the fish community upstream. The Shooter Ditch Confluence Reach is located less than one quarter of mile upstream of the stream restoration projects. Fish that utilize the restored sections as primary habitat likely also spend time in creek sections immediately adjacent to the restored sections. Thus collecting these fish in the fish surveys would not be unusual. Second, precipitation levels in 2001 were very close to the normal expected precipitation level. This likely reduced any stresses caused by low creek water levels. The improvement in climatic conditions may have helped improve the fish community at the Shooter Ditch Confluence.
| YEAR | WHITE OAK IBI |
STREAM OVERLOOK IBI |
SHOOTER DITCH CONFLUENCE IBI |
COMBINED IBI |
1997 |
26 |
28 |
30 |
34 |
1998 |
22 |
32 |
26 |
34 |
1999 |
26 |
38 |
32 |
38 |
2000 |
42 |
42 |
38 |
44 |
2001 |
42 |
42 |
40 |
46 |
2002 |
28 |
28 |
24 |
34 |
Table 5. Central Corn Belt Plain IBI modified for the East Branch of the Little Calumet
River scores by year and reach. Combined IBI is for all three reaches calculated together.
Section III. Conclusions and Recommendations
In stream habitat modifications and bank stabilization efforts at the White Oak Reach (Reach 1) and the Stream Overlook Reach (Reach 2) have positively influenced fish community structure. The presence of salmonid species, such as coho salmon and steelhead, indicate the presence of high quality habitat. Additionally, juvenile steelhead observed during the 2001 sampling suggest that streambed restoration has provided adequate spawning gravel within Coffee Creek and that water quality is sufficient to support successful reproduction of this sensitive species. The increase in the combined Coffee Creek IBI ratings from poor in 1997 to fair in 2000 and 2001 further supports the hypothesis that restoration efforts have improved the Coffee Creek fish community. The IBI scores observed in 2000 and 2001 in the restored reaches are among the highest biotic integrity scores of all creeks in the Little Calumet drainage (Simon, 1991). The increase in IBI scores at the Shooter Ditch Confluence Reach (Reach 3) that has occurred concomitantly with the increase in IBI scores at the restored reaches suggest improvements made downstream may be enhancing upstream fish communities.
A slight degradation in fish community was observed in 2002. Evidence of this degradation included the absence of salmonids, the presence of high numbers of tolerant individuals, and the high percentage of DELT in the fish collected during the 2002 survey. Below normal rainfall likely decreased creek water levels and increased water temperature. These environmental stresses may be responsible for the observed decrease in biotic integrity in Coffee Creek. Continued sampling is recommended to monitor the fish community in Coffee Creek and ensure that the results of the 2002 sampling are not the beginning of a trend toward degradation of the fish community. Continued water quality and macroinvertebrate sampling is also recommended to better identify the reasons for any observed degradation in biotic integrity.