2001 Monitoring Reports

Section III. Fish Community Survey

Introduction

This report documents the fifth year of fish sampling efforts within three stream reaches in Coffee Creek, an indirect tributary to Lake Michigan. Coffee Creek drains approximately 16 square-miles of northeastern Porter County, Indiana.

The stream flows north before joining the east branch of the Little Calumet River, which eventually enters Lake Michigan at Burns Harbor in Portage, Indiana. Coffee Creek is classified as a spring-fed, cold, headwater stream with a predominantly sand substrate. This habitat is home to many native fish and is suitable to migratory salmonids seeking potential spawning grounds. The study site is located within the Coffee Creek Watershed Preserve, a 167-acre natural area within Coffee Creek Center. Significant stream improvements were made in 1999 within reaches that pass through the development. Upstream of the development, however, Coffee Creek remains ditched to drain agricultural land. Bank erosion and resulting sedimentation have negatively impacted this stream reach. The purpose of the annual fish community surveys is to document positive or negative impacts on fish communities resulting from residential and commercial development within the Coffee Creek Watershed.

Index of Biotic Integrity

Biological communities reflect watershed conditions since they are sensitive to changes in a wide array of environmental factors (Karr, 1981). Karr (1981) proposed that fish have numerous advantages as indicator organisms for biological monitoring programs. Karr (1981) first developed the Index of Biotic Integrity (IBI) which Simon (1997) further modified for use in evaluating biological integrity of lotic, warm water, stream-fish communities located in the Northern Indiana Till Plain Ecoregion of Indiana. Karr and Dudley (1981) defined 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 sampling sites have been collected, values for the 12 metrics are compared with their corresponding expected values (Simon 1997), 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 should be cautioned that Simon (1997) developed IBI expectations primarily for warm-water streams of the Northern Indiana Till Plain; however, Coffee Creek has been classified as a cold-water stream being primarily spring-fed. Temperatures during summer months seldom exceed approximately 75°F (24°C). Because fewer species typically inhabit cold-water streams (Waters, 2000), applying warm-water expectations to a cold-water stream could potentially skew IBI estimates. Despite potential difficulties, the methodology of Simon (1997) 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 cold-water streams in Indiana. Additionally, Coffee Creek does not closely fit a typical cold-water 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, it 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 cold water systems.

Table 2 shows the calculated IBI scores and corresponding integrity class for each site sampled during 2001, 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 44 at Reach 1 to a low of 36 at Reach 3. Coffee Creek's average IBI score, 39, places it in the "Fair-Poor" integrity class. All three reaches scored consistently poor for percent headwater species, percent pioneer individuals, and percent lithophilic individuals.

SITE (LOCATION)	IBI	INTEGRITY CLASS
Coffee Creek Reach 1	44	Fair
Coffee Creek Reach 2	38	Fair-Poor
Coffee Creek Reach 3	36	Fair-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 III. Northern Indiana Till Plain (Simon, 1997).

Making among year comparisons of the number of fish caught per reach is difficult because time and effort as well as sampling conditions have varied among years. For example, the 1998 survey resulted in lower numbers of collected specimens due to a rain event that caused high, turbid water, impairing the field crew's ability to see and capture fish. Simon's (1997) sampling protocol was adopted for this survey to minimize differences in sampling procedures in future years and allow for an accurate comparison among IBI scoring metrics. Because of the comparison difficulties, the most relevant parameter for comparison among years is relative or percent composition of each species (Figure 15). Since 1997, the white sucker, a highly tolerant species, has declined, while species of intermediate tolerance such as the central stoneroller and common shiner have increased in relative abundance. The percentage of northern hogsucker, a sensitive species, remained stable from 1997 to 2001. The common shiner, which has never been identified in past surveys, comprised 10% of the 2001 sample. Additionally, samples prior to 2001 have never documented the presence of hornyhead chub, another sensitive species.

Figure 15. Coffee Creek relative or percent fish community composition by year. Data are shown for the dominant species and for species of particular interest.

Table 4 contains historical IBI estimates for comparison among years. In general, biotic integrity has been maintained and perhaps has even slightly improved since 1997. IBI scores however have remained depressed due to low percentages of headwater species and simple lithophilic spawners, and high percentages of pioneer individuals. Although habitat improvements and streambank stabilization have been implemented within the Coffee Creek project site, the biotic integrity is still "Fair-Poor" and is probably impacted by conditions and practices in the surrounding watershed, although overall IBI scores may be underrated by biases in the IBI as discussed earlier.

YEAR	REACH 1 IBI	REACH 2 IBI	REACH 3 IBI	AVERAGE (MEAN)
1997	30	32	34	32
1998	34<	32	30	32
1999	28	34	32	31
2000	38	38	40	39
2001	44	38	36	39

Table 4. IBI scores by year and reach. Mean IBI is all three reaches calculated together.

Figure 15. Relative Fish Community, Percent Community Composition for Dominant Species by Reach for 1997 data.

Reach-to-Reach Comparison

Reach comparisons along Coffee Creek point out both similarities and differences in fish community structure (Figure 16). Reaches 1 and 2 contained similar fish communities. Only the relative composition of hornyhead chub and common shiner differed. Reach 3 contained larger populations of tolerant species such as creek chub and white sucker and fewer numbers of sensitive species like northern hogsucker and rainbow darter when compared to Reaches 1 and 2 (Appendix 24). The catch per unit effort (CPUE) in Reach 3 was less than that observed in Reaches 1 and 2 (Appendix 24). CPUE refers to the number of fish collected per length of stream sampled. Less healthy reaches oftentimes support lower numbers of fish and other aquatic organisms .

Figure 16. Coffee Creek relative or percent fish community composition by reach. Data are shown for the dominant and some indicator species.

Channelization and degraded in-stream habitat may have negatively altered the fish community in Reach 3 when compared to Reaches 1 and 2. "Channelization has major impacts on stream ecosystems, leading to reduced special habitat, greater temporary instability, less stream-floodplain interaction, and shifts in fish community structure" (Shields et al., 1998). Habitat degradation associated with channelization can cause the elimination of longer lived, larger species, and favor small, short-lived opportunistic tolerant species like those seen in Reach 3 of Coffee Creek (Rapport et al, 1985). Silt deposition in Reach 3 may be responsible for the large populations of tolerant species and small number of sensitive species and lithophilic spawners. According to Poff et al. (1997) "human modification of natural hydrologic processes disrupts the dynamic equilibrium between the movement of water and the movement of sediment that exists in free-flowing rivers and streams". This disruption alters features that constitute habitat for aquatic and riparian species. A low percentage of simple lithophilic spawners and insectivores is typical of a stream disturbed by siltation. Silt can cover sand, gravel, or cobble substrate reducing successful spawning and reproduction of lithophilic species. Additionally, when siltation reduces habitat availability for aquatic insects insectivorous fish may become food-limited.

IBI Comparison

IBI values ranged from a high of 44 at Reach 1 to a low of 36 at Reach 3. No reaches received good (48-52), excellent (58-60), or very poor (<28) scores. Five metrics generally contributed to low IBI scores for the three study reaches including: low percentage of headwater species, high percentages of pioneer species, low percentages of simple lithophilic individuals, high CPUE, and lack of insectivorous individuals. Lack of headwater species and overabundance of pioneer species lowered IBI scores in all three study reaches of Coffee Creek. According to Simon (1997), the presence of headwater species indicates permanent habitat with low environmental stress. The lack of these species might indicate that undesirable conditions such as high, unstable flow occur with some frequency. Overabundance of pioneer species was found throughout the stream. Simon (1997) indicates that pioneer 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.