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WOODRIDGE LAKE 2014 FISHERY REPORT

Prepared by:

Mark D. Cornwell Eric Malone

Benjamin German

State University of New York College of Agriculture and Technology at Cobleskill

Department of Fisheries, Wildlife & Environmental Science Cobleskill, NY 12043

Prepared For:

Woodridge Lake Property Owners Association

Goshen, CT

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TABLE OF CONTENTS

PAGE # SECTION/TOPIC 4 SUMMARY AND RECOMMENDATIONS

5 INTRODUCTION

5 MATERIALS AND METHODS

9 RESULTS AND DISCUSSION

28 CONCLUSION AND RECOMMENDATIONS 30 REFERENCES INDEX OF TABLES

TABLE # TITLE PAGE # Table 1 Woodridge Lake Boat Electrofishing Locations and Effort 7 Table 2 Size Categories of Fish Commonly Found in Woodridge Lake 9 Table 3 Water Chemistry Profile of Woodridge Lake on 25 July 2013 9 Table 4 Water Chemistry Profile of Woodridge Lake Fall 2013 10 Table 5 Table 6

Water Chemistry Profile of Woodridge Lake Fall 2014 Size and Abundance of Fish Collected by Boat Electrofishing

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Table 7 Woodridge Lake Fishery Survey Results 2001, 2009, 2013 and 2014 13 Table 8 Woodridge Lake CPUE (fish/hr) Compared to Selected Northeast Lakes 14 Table 9 Woodridge Lake Bracketed Size Calculations for PSD and RSD Values 14 Table 10 Calculations to Determine the Predator-Prey PSD Relationship 15 Table 11 Accepted Stock Density Index Ranges for Balanced Fish Populations 15 Table 12 Stock Density Index Objective Ranges for Largemouth Bass

& Bluegill Under Three Different Management Strategies 15

INDEX OF FIGURES

FIGURE # TITLE PAGE # Figure 1 Map of Woodridge Lake Illustrating ten All-Fish 7 Electrofishing Sites Sampled in Fall 2013 and 2014 Figure 2 Bracketed Catch Categories Illustrating How PSD and RSD 8

Values Are Determined Figure 3 Graphical Illustration of Woodridge Lake Catch per Unit 12

Effort Fall 2013 and 2014 Figure 4 Relative Abundance (by #) of Fish Species for Woodridge 12

Lake Fall 2013 2014

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FIGURE # TITLE PAGE # Figure 5 Proportional Stock Density Tic-Tac-Toe Grid Showing 16 Predator-Prey Relationship

Figure 6 Woodridge Lake Bluegill Length Frequency Distribution 16 by boat electrofishing

Figure 7 Photograph of a Bluegill Hybrid 17 Figure 8 Length Frequency (L-F) Distribution of Woodridge Lake 18

Bluegill 2013 and 2014 Figure 9 Overlay of Length Frequency for 2013 and 2014 Bluegill 18 Figure 10 Length Frequency (L-F) Distribution of Woodridge Lake 19

Pumpkinseed 2013 and 2014 Figure 11 Length Frequency (L-F) Distribution of Woodridge Lake 19

Black Crappie 2013 and 2014 Figure 12 Length Frequency Distribution (L-F) of Woodridge Lake 20

Black Crappie comparison from surveys during Fall 2013 and 2014. Figure 13 Length Frequency (L-F) Distribution of Woodridge Lake 20

Hybrid Sunfish 2013 and 2014 Figure 14 Length Frequency (L-F) Distribution of Woodridge Lake 21

Yellow Perch 2013 and 2014 Figure 15 Length Frequency (L-F) Distribution of Woodridge Lake 21

Chain Pickerel 2013 and 2014 Figure 16 Length Frequency (L-F) Distribution of Woodridge Lake 22

Chain Pickerel comparison from surveys during Fall 2013 and 2014. Figure 17 Length Frequency (L-F) Distribution of Woodridge Lake 22

Largemouth Bass 2013 and 2014 Figure 18 Length Frequency (L-F) Distribution of Woodridge Lake 23

Smallmouth Bass 2013 and 2014 Figure 19 Length Frequency (L-F) Distribution of Woodridge Lake 23

Rockbass 2013 and 2014 Figure 20 Length Frequency (L-F) Distribution of Woodridge Lake 24

Rainbow Trout 2013 and 2014 Figure 21 Length Frequency (L-F) Distribution of Woodridge Lake 25

Brown Bullhead 2013 and 2014 Figure 22 Length Frequency (L-F) Distribution of Woodridge Lake 25 Yellow Bullhead 2013 and 2014

Figure 23 Length Frequency (L-F) Distribution of Woodridge Lake 26 Spottail Shiner 2013 and 2014

Figure 24 Length Frequency (L-F) Distribution of Woodridge Lake 26 Golden Shiner 2013 and 2014

Figure 25 Length Frequency (L-F) Distribution of Woodridge Lake 27 Tessellated Darter 2013 and 2014

Figure 26 Length Frequency (L-F) Distribution of Woodridge Lake 27 White Sucker 2013 and 2014

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SUMMARY & RECOMMENDATIONS

1. This report is a combination of fisheries data collected during 2013 & 2014. 2. This fisheries survey was conducted at the request of the Woodridge Lake Property Owners

Association (WLPOA) on 31 August and 3 September 2013 and was repeated again in 2014 on 15 and 18 September.

3. This survey was conducted in concert with Eurasian Water Milfoil (EWM) biocontrol methods employed by Paul Lord from SUNY Oneonta, mainly to characterize the relationship between bluegill, predators of bluegill and their relationship to biocontrols of EWM.

4. A Smith-Root SR-18 boat electrofisher was used to sample ten (10) sites around the lake. Sample sites, effort and methods were similar in 2013 & 2014.

5. Catch rates of most common fish were remarkably consistent between years (Total CPUE for all fish 2013=1685 fish/hr compared to 2014=1650 fish/hr).

6. In 2013, 3,723 fish in 19 species were collected and individually measured. In 2014, 3,384 fish in 24 species were collected and individually measured.

7. Results found high catch/effort (CPUE in fish/hr) of young of the year bluegill (2013=823/hr, 2014=845/hr.).

8. This survey found smallmouth bass were more abundant than largemouth bass in 2013 and are larger than largemouth bass in 2013 and 2014. This is a very interesting relationship.

a. In most smallmouth-largemouth systems, largemouth are dominant. Smallmouth also had a larger average size (173mm) than did largemouth (116mm).

b. While smallmouth dominance may be desirable (many lakes would love this problem), this is uncommon. The cause of the smallmouth dominance over largemouth cannot be determined at this time.

c. Possible causes may include: (1) water level manipulation disrupting largemouth spawning (2) bluegill robbing largemouth nests (3) a combination of plant/habitat management strategies may affect largemouth spawning success, giving smallmouth the advantage. This condition needs further study.

9. Similar to Wagner (2012 & 2013), in 2013 we found a zone of anoxic bottom water that persisted at least a month (25 July to 3 September). Woodridge Lake is too warm for trout to regularly over summer and bottom water is too anoxic. In 2014, the Lake was mixed from top to bottom at 19°C and the anaerobic zone at the lake bottom was absent.

10. Woodridge is a warm-cool water fishery. The trout fishery should be a put-enjoy-take fishery. Fall stocking of trout to increase angling opportunity could be considered. Despite the warm water, a few trout (n=18 in 2013, n=16 in 2014) were captured in this survey.

11. No walleye were collected in 2013 and one walleye (length=506mm or 20”) was collected in 2014.

a. Continue to stock walleye at a density of at least 20/acre (or more) to increase angling opportunity and provide additional predation pressure on bluegill.

12. One large tiger muskie was captured each year (2013 length= 43”, in 2014 length = 33” pictured on the cover) was collected.

a. Continue stocking tiger muskie to increase angling opportunity and provide additional predation pressure on bluegill.

10. Bluegill management should continue to be a priority. In addition to stocking walleye, largemouth bass are usually the species that is recommended for bluegill control. To increase natural recruitment of largemouth bass, a stable littoral zone is necessary. A stable littoral may increase largemouth bass spawning success, placing additional predation on bluegill. However, this littoral stability (no drawdown) may be contrary to milfoil management goals.

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INTRODUCTION

This survey was conducted at the invitation of the Woodridge Lake Property Owners Association (WLPOA). Early in 2012, John Plummer, a representative of the WLPOA lake and dam committee contacted the SUNY Cobleskill Department of Fish, Wildlife and Environmental Studies with a request for a consultation regarding the fishery of Woodridge Lake. Our contact with WLPOA in 2014 was Ken O’Hara who helped facilitate this contract. The WLPOA employs a multi-faceted approach to managing EWM over the last 15 years including: drawdown, herbicides, suction harvesting, and mechanical harvest. There was concern among several lake residents that the milfoil management techniques may be at the detriment of the fishery. After a site visit and initial consult, a contract between the Research Foundation of the State of New York and the WLPOA was developed to perform a 3-yr fisheries study of Woodridge Lake. This document summarizes the first two years of this project. The fishery of Woodridge Lake has been studied several times in the last 15 years. The Connecticut DEP surveyed the Lake in 2008 and 2012. The CTDEP study was primarily focused on game fish and presented data in catch/hr of stock, quality and preferred size fish. ENSR International performed a fisheries study in 2001 that included gill nets. Aquatic Environmental Consultants added a fisheries survey of the lake again in 2009. Of particular interest is the catch rate of YOY bluegill. These historic studies were conducted in way consistent with managing the fishery for game fish (similar to CTDEP). Data from these studies did not contain a great deal of information on small YOY (Young-of-Year) fish. With aquatic plant management (EWM) as the primary goal, fisheries data should be collected in a way that allows us to measure the abundance of young-of-year bluegill and other fish that may prey on herbivores of milfoil. Gleaning these details from historic data is difficult to impossible, hence the need for this 3-year survey conducted concurrently with EWM work by Paul Lord at SUNY Oneonta. The first electrofishing survey was conducted by SUNY Cobleskill in late August 2013 to collect more detailed information about the status of the fishery and was repeated with the same methods in early September 2014 to note any changes in the fishery. Goals and objective of the survey were to perform a warmwater fisheries survey in concert with a Eurasian Water Milfoil (EWM) herbivory study by Paul Lord from SUNY Oneonta. SUNY Cobleskill (Mark Conwell) and SUNY Oneonta (Paul Lord) have a 15 year history of studying the interactions between fish, EWM herbivores and the EWM. The goal was to perform a typical warmwater boat electrofishing survey of Woodridge Lake with an eye toward determining the density of sunfish (bluegill) and predators of those sunfish in Woodridge Lake. A secondary goal was to provide the WLPOA three years data, collected in the same manner, providing insight and suggestion on how to manage the recreational fishery. 2014 was year-2 of this study. MATERIALS & METHODS Unlike past surveys, the focus on game fish was only part of the objective. Most fish and game agencies primarily focus on the management of sport and game fish, and rightly so. Most of the money that goes to fund those agencies is derived from license sales and taxes on associated sporting gear. Hence, fish and game surveys, like the studies in 2008 and 2012 (CTDEP) are focused on game fish and may not collect young of the year fish. Similarly, consultants have their own way of collecting and analyzing the data based on the limitations of their gear and crew. Not all surveys are conducted the same way.

The 2013 survey was conducted over three nights, 30, 31 August 2013 & 3 September. All survey nights started around 7 p.m. and lasted through the night. A lightning storm on the 31st shortened the survey on that night and forced the crew to return on 3 September. The Fall 2014 survey was conducted on 15 and

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18 September. Electrofishing surveys began at 7 p.m. and continued until midnight. Weather was more stable in 2014 and electrofishing was concluded in two nights instead of three. Electrofishing is the use of electricity to catch fish. Direct (DC) electrical current is used to produce a temporary erratic swimming response and anesthetic effect that allows a netter on the front of an electrofishing boat to collect immobilized fish. If done correctly, the effects on the fish are negligible, with all of the fish returned to the water immediately after data collection. Despite warm water temperatures (near 70°F) the crew witnessed no mortality on this survey. The survey was conducted using a Smith Root SR-18 Electrofishing boat with a 7.5kv generator powered pulsator (GPP). This is a standard boat used by most fish and game agencies. Ten sites were chosen that represented a majority of habitats present. These same sites were originally surveyed in 2013 and were revisited in Fall 2014. GPS coordinates were recorded at the start and end point of each sample location (Table 1). Sample effort was recorded in seconds for each individual site (Table 1.). All fish were identified, measured and released before proceeding to the next location. This survey was an all-fish survey. Two scappers (netters) were deployed on the bow of the boat to net all fish in the electric field. An all fish survey means that the netter is given specific instructions to net all the fish. Ideally, equal effort goes into netting a 50mm young-of -year bluegill as a 500mm bass. Bias does occur and the netters do tend to gravitate toward netting larger fish. However, this problem is most likely uniform across time and crews. Great care is used to pick the individuals that man the netting stations on the boat. In fact, the exact same individuals were present for both 2013 & 2014 surveys. Gear, effort and crew were similar.

The success (and the effectiveness) of the survey depends on:

1.) Effectiveness of the gear and its configuration. Most electrofishing boats fish differently. 2.) Efficiency of the crew running the gear. All captains run the gear differently, with differing

survey design. In 2014, the exact same captain and crew repeated the 2013 survey. 3.) The efficiency of the netters on the bow of the electrofishing boat. All netters are not created

equally. Capture efficiency varies with experience, physical ability and fatigue. 4.) The bias of netters. Usually selecting for larger fish and against smaller fish (like YOY bluegill). 5.) The timing of the survey. A warmwater survey primarily focused on centrachids (sunfish) should

occur when the water temperatures are warmer than 20°C but not greater than 27°C. This usually means a late May-June or September and October survey. This survey was delayed until water temperatures cooled at the end of August-beginning September.

Fish behavioral response to electrofishing is three-fold: (1) Fright (2) Tetany and (3) Electronarcosis. Fright is when a fish “senses” the electrical field and bolts out of the area being fished. Essocids, such as pickerel, pike and muskie have long cylindrical bodies and are particularly adept at sensing the electricity. Members of this family (muskie, pike and pickerel) are underrepresented in most electrofishing surveys. Their abundance is usually greater than the electrofishing CPUE indicates. Tetany occurs when a fish’s muscles contract and their gills flare in reaction to the electricity, with the fish twitching in small, fast movement. The gear should be set so the fish spend the least amount of time in this stage, as prolonged tetany can increase mortality. Electronarcosis (an “electricity induced” sleep) is the relaxing of the fish during a stage of equilibrium loss. Fish should move quickly from fright to tetany, then into a period of narcosis. Fish should regain equilibrium within a few minutes. To our knowledge, no mortalities were observed based on these surveys.

The above reasons dictate that shallow water of less than 2.5m is electrofished at night. Gamefish are more likely to be inshore at night. Fish that experience fright, and run from the boat are pinned by the

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electric field against the shoreline or the bottom. Electrofishing boats are only effective in shallow, littoral, near-shore water that can be effectively reached by a netter leaning over the bowrail of the electrofishing boat.

Table 1. Woodridge Lake boat electrofishing locations and effort from Fall 2013 and 2014 surveys.

Figure 1. Map of Woodridge Lake illustrating ten electrofishing sites sampled in Fall 2013 and 2014.

Collected fish were identified and measured in maximum total length (millimeters) on a measuring board. Results of game fish and non-game fish are expressed in catch/hr in two (2) length frequency histograms (one for each year) for each species (Figures 11-17). These standard survey methods and electrofishing

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boat design are routinely used by the New York State Department of Environmental Conservation (NYSDEC), Connecticut DEP and most other fish and game agencies. Electrofishing data were entered into an EXCEL file. Metrics calculated from the data include:

(1) Relative Abundance: the composition of each species as a percentage of the total community. (2) Catch Per Unit Effort (CPUE): the catch of each species as a function of time, calculated by

dividing the number of individuals of each species by the hours fished for that species. This the most widely recognized index of abundance. This metric is expressed in fish/hr.

(3) Length-Frequency Analysis: the number of individuals of each species plotted on a graph clustered by their size. This helps identify year classes and year class failures and allows one to visualize the data and identify trends.

(4) Proportional Stock Density (PSD): is the ratio of quality sized fish to stock sized fish. This was calculated for each species.

i. PSD= # of quality size / # stock size. (5) Relative Stock Density (RSD): the ratio of preferred sized fish to stock sized fish

i. RSD= # of preferred / # stock size PSD and RSD are numerical descriptors that are often used to understand fish population dynamics. “Stock” length is defined as the approximate length at maturity for a species (Kohler and Hubert 1999) and is the size fish that an angler is most likely to catch. Stock length fish are the minimum size when a fish “enters” the fishery. For most prey species, stock length is 5”. For largemouth and smallmouth bass, stock length is 8”. The actual “stock” of each species is the number of fish that are at or above the stock length. “Quality” length is the minimum size of fish that most anglers like to catch (Zale, Parrish and Sutton, 2013). For prey species this size is typically 8”, and for bass it is 12”. PSD describes the ratio of these “quality” sized fish to the stock of that species. “Preferred” length is approximately 50% of the size of the world record of a particular fish species measured (Zale, Parrish and Sutton, 2013). For prey species, this is typically 10”, and for bass it is 15”. RSD describes the ratio of these “preferred” sized fish to the stock of that species Figure 2. Bracketed catch categories illustrating how PSD and RSD (as % of world record) values are determined.

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Table 2. Size Categories of Fish Commonly Found in Woodridge Lake adapted from Willis, Murphy and Guy (1993). These sizes are to calculate PSD & RSD.

Please take note that there is a problem with how data can be collected and interpreted. A “stock” size bluegill is 8cm (80mm) and may not be targeted by an electrofishing crew. In fact, it is likely that most electrofishing crews, because of time limitations and the laborious intensity of collecting all YOY bluegill, may let sub-stock size fish pass through the field uncollected. For the purposes of managing the herbivores of EWM, small YOY bluegill should be collected, counted and measured. Some agencies deal with this problem with a “bulk fish form” which takes a subsample of fish (maybe 50 of 2000), measures them, and then the netters try to do a rough count as the fish pass through the field undisturbed. This is sometimes done out of necessity due to time and crew limitations. Catching, then measuring all these small fish is tiring, laborious, expensive, and may not be necessary if the primary survey objective is focused on gamefish. Herein is a main point for consideration. All the fisheries surveys in the past have focused primarily on gamefish. Unless a fisheries crew is specifically asked, most will not collect and process all YOY sunfish. This survey did process ALL fish that we caught, even YOY bluegill. RESULTS & DISCUSSION Table 3. Water Chemistry Profile of Woodridge Lake on 25 July 2013. Adapted from Lord & Pokorny (2013).

* Line illustrates 2013 Dissolved Oxygen Concentrations <5mg/L below 4m

Species E M E M E M E M E Mbanded killifish na na na na na na na na na nablack crappie 5 130 8 200 10 250 12 300 15 380blacknose shiner na na na na na na na na na nabluegill 3 80 5 150 8 200 10 250 12 300brown bullhead 6 150 9 230 12 300 15 380 18 460brown trout 8 200 13 330 na na na na na nabluntnose shiner na na na na na na na na na nachain pickerel 10 250 15 380 200 510 25 630 30 760channel catfish 11 280 16 41 240 61 28 710 36 910creek chubsucker na na na na na na na na na nagolden shiner na na na na na na na na na nagreen sunfish 3 80 5 150 8 200 10 250 12 300hybrid (bluegill) sunfish 3 80 5 150 8 200 10 250 12 300largemouth bass 8 200 12 300 15 380 20 510 25 630Pumpkin Seed 3 80 5 150 8 200 10 250 12 300rainbow trout 8 200 13 330 na na na na na naredbreast sunfish na na na na na na na na na narockbass 4 100 7 180 9 230 11 280 13 330smallmouth bass 7 180 11 280 14 350 17 430 20 510spottail shiner na na na na na na na na na natesselated darter na na na na na na na na na natiger muskey 14 350 21 530 28 710 34 860 44 1120Walleye 10 250 15 380 20 510 25 630 30 760white sucker na na na na na na na na na nayellow bullhead 6 150 9 230 na na na na na nayellow perch 5 130 8 200 10 250 12 300 15 380*Measurements are in E (English, inches) and M (metric, millimeters).

Stock Size Quality Size Prefered Size Memorable Size Trophy Size

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Table 4. Water Chemistry Profile of Woodridge Lake on 31 August 2013.

Depth (m)

Temp (°C)

Conductivity

(mS/cm) pH D.O.

(mg/L) Surface 23.90 0.17 8.50 8.40

0.60 23.90 0.17 8.50 8.50 1.20 23.93 0.17 8.52 8.53 1.80 23.84 0.17 8.48 8.37 2.40 23.71 0.16 8.43 8.27 3.00 23.39 0.17 8.35 7.87 3.70 23.04 0.17 8.13 5.30 4.30 22.76 0.17 7.98 3.82 4.90 22.27 0.17 7.87 1.97 5.50 21.52 0.18 7.78 0.80 6.10 20.93 0.19 7.67 0.46 6.70 20.03 0.20 7.55 0.40

*Line illustrates 2013 Dissolved Oxygen Concentrations <5mg/L below 4m.

The water chemistry profile on 25 July (Lord & Pokorny, 2013) and this study on 31 August 2013 indicate that Woodridge was stratified for a least a month, leading to an increased anoxic zone near the bottom. As indicated many times by Wagner (2013) and others, Woodridge is a shallow lake that should be considered a warmwater fishery. Trout should be stocked on a put-and-enjoy basis as they will most likely perish in the summer when water temperatures warm above 20°C. If the lake does stratify (as it did in 2013), trout may be trapped between water that is too anaerobic near the bottom and too warm near the top. A trout summerkill may result.

Table 5. Water Chemistry Profile of Woodridge Lake on 18 September 2014.

Depth (m)

Temperature (°C)

Conductivity (mS/cm) pH

DO (mg/L)

surface 19.86 0.19 6.36 8.18 0.9 19.86 0.19 6.55 8.34 1.8 19.86 0.19 6.69 8.41 2.7 19.86 0.19 6.82 8.50 3.7 19.84 0.19 6.92 8.60 4.6 19.56 0.19 6.99 8.52 5.5 19.29 0.19 7.02 8.23 6.4 19.16 0.18 7.02 8.02 6.8 19.15 0.19 7.02 7.85

The water chemistry profile recorded on 18 September 2014 differs from the results that were collected in 2013. In 2014, the lake was not stratified. The dissolved oxygen levels and temperature were relatively constant throughout the water column indicating that the lake was mixed and not stratified as it was in the previous year. The lake was quite warm for trout at >19°C. Trout die or are severely stressed at 20°C.

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In 2014, we collected and measured 3384 individual fish from 24 different species, which is very similar to the results of the 2013 survey. Bluegill were the most abundant species (51%) and panfish continue to be the most dominant group (76%) within this warmwater fishery. The previous survey conducted in Fall 2013 with the same methods and sites collected and measured 3723 individual fish representing 19 species. Bluegill composed almost half of the catch by number (48%). Bluegill, perch and rock bass (the top three panfish) were abundant, composing 81% of the total catch. Table 6. Size and abundance of fish collected by boat electrofishing during Fall 2013 and Fall 2014.

Species Count (2013)

Count (2014)

CPUE (#/hr) (2013)

CPUE (#/hr) (2014)

Avg Size (mm) (2013)

Avg Size (mm) (2014)

banded killifish 1 0 0.5 0.0 57 0 black crappie 46 148 20.8 72.1 84.7 89.6

blacknose shiner 0 10 0 4.9 0 44.4 bluegill 1819 1735 823.1 845.8 50.2 19.0

brook silverside 0 2 0 1.0 0 76.0 brown bullhead 4 7 1.8 3.4 278.8 290.0

brown trout 2 12 0.9 5.8 363.5 391.3 chain pickerel 41 81 18.6 39.5 252.8 109.6

channel catfish 0 14 0 6.8 0 340.7 creek chub sucker 1 6 0.5 2.9 348.0 93.2

golden shiner 7 4 3.2 1.9 68.3 73.5 hybrid (bluegill) sunfish 13 7 5.9 3.4 224.2 239.4

largemouth bass 160 154 72.4 75.1 116.6 48.6 pumpkinseed 194 126 87.8 61.4 108.4 42.6 rainbow trout 18 4 8.1 1.9 370.9 404.8

red breasted sunfish 0 17 0 8.3 0 238.1 rock bass 350 282 158.4 137.5 142.2 42.0

smallmouth bass 177 134 80.1 65.3 173.1 68.6 spottail shiner 29 20 13.1 0.0 69.9 0.0

tessellated darter 5 1 2.3 9.7 46.0 49.6 tiger muskie 1 1 0.5 0.5 1092.0 842.0

walleye 0 31 0 0.5 0 506.0 white sucker 16 12 7.2 15.1 443.6 477.7

yellow bullhead 0 576 0 5.8 0 251.7 yellow perch 839 148 379.6 280.8 95.9 46.1

Total 3723 3384 1684.6 1649.6

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Figure 3. Graphical illustration of Woodridge Lake Catch per Unit Effort Fall 2013 and 2014.

The bluegill (Lepomis macrochirus) population far exceeds other fish species. This survey collected 1,819 and 1735 bluegill in 2013 & 2014 respectively. The panfish (bluegill, pumpkinseed, yellow perch, rock bass, black crappie and a bluegill hybrid, (Figure 7) accounted for over 85% of the fish community of Woodridge Lake. Trout were stocked into Woodridge several years ago to increase angling opportunity. Previous studies collected walleye (Sander vitreus) introduced through a conscious stocking effort (Figure 4). The 2014 survey caught one large 506mm (20”) walleye.

Figure 4. Relative abundance (by #) of fish species for Woodridge Lake Fall 2013 and 2014.

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Woodridge Lake CPUE Changes from 2013-2014

2013 (#/hr) 2014 (#/hr)

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Table 7: Woodridge Lake fishery survey results 2001, 2009, 2013 and 2014.

The SUNY Cobleskill 2013 (and again in 2014) fisheries survey collected more fish than 2001 (ENSR) and 2009 (AEC) surveys combined. Ten (10), 16, 19 and 23 species were caught in 2001, 2009, 2013 and 2014 respectively. We plan to compile all these data for a multi-year analysis in 2015. In 2001 (ENSR), gill nets were used to collect data. 506 fish were captured with the majority being yellow perch. Other species captured in 2001 were golden shiner (Notemigonus crysoleucas), brown bullhead (Ameiurus nebulosus), white sucker (Catostomus commersonii), pumpkinseed, rock bass, bluegill, smallmouth bass, chain pickerel (Esox niger), and largemouth bass. In 2009 (AEC), two shore seines and an electrofishing boat were used to sample the lake. 1622 fish were captured with the majority being brook silversides (Labidesthes sicculus). Walleye were also captured in 2009. In 2013, 3723 total fish were sampled using a Smith Root Electrofishing boat. No walleye were captured during the 2013 survey and one walleye was captured in 2014.

Species count avg length (mm) count avg length (mm) count avg length (mm) count avg length (mm)Banded Killifish 0 0 15 64 1 57 0 0Black Crappie 0 0 7 318 46 85 148 90

Blacknose Shiner 0 0 0 0 0 0 10 44Bluegill 1 192 88 38 1819 50 1735 54

Brook Silverside 0 0 1000 76 0 0 2 76Brown Bullhead 2 360 4 243 4 279 7 290Brown Trout 0 0 0 0 2 364 12 391

Chain Pickerel 1 345 31 470 41 253 81 110Channel Catfish 0 0 0 0 0 0 14 341

Creek Chubsucker 0 0 2 330 1 348 6 93Golden Shiner 1 0 0 0 7 68 4 74Hybrid Sunfish 0 0 0 0 13 224 7 239

Largemouth Bass 4 245 86 89 160 117 154 49Pumpkinseed 8 184 81 114 194 108 126 43

Rainbow Trout 0 0 1 406 18 371 4 405Redbreast Sunfish 0 0 5 216 0 0 17 238

Rock Bass 4 156 52 140 350 142 282 42Smallmouth Bass 3 206 92 64 177 173 134 69Spottail Shiner 0 0 0 0 29 70 0 0

Tessellated Darter 0 0 0 0 5 46 20 50Tiger Muskellunge 0 0 3 991 1 1092 1 842

Walleye 0 0 3 445 0 0 1 506White Sucker 1 409 15 445 16 444 31 478

Yellow Bullhead 0 0 0 0 0 0 12 252Yellow Perch 481 219 137 116 839 96 576 46TOTALS 506 1622 3723 3384

201320092001 2014

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Table 8. Woodridge Lake CPUE (fish/hr) compared to selected NE lakes dominated by bluegill & EWM

The above data indicate bluegill are abundant in Woodridge Lake, approaching some of the higher values that we have seen in Northeast Lakes. Many lakes that are dominated by milfoil often have fish communities that are also dominated by small, stunted bluegill. The theory is that milfoil acts as predation refuge for the bluegill, allowing bluegill populations to grow unfettered. Table 9. Woodridge Lake Bracketed Size Calculations for PSD and RSD Values. These are the numbers of fish used to calculate the PSD & RSD values in the last two columns.

* n/a denotes a sample size too small (<30 individuals) to determine PSD

Woodridge 12-Mile Findly ChautauquaSpecies Aug-13 Oct-07 Oct-08 Oct-09 Jun-04 Oct-04 May-05 Oct-05 May-06 Jun-10 Jun-00 Oct-04 Jun-04 Oct-04 Aug-03 Aug-03

1 banded killifish 0.5 10.8 38.1 28.9 0.0 0.0 0.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.32 brown bullhead 1.8 5.0 8.7 20.1 23.7 3.0 8.6 3.3 11.5 1.2 4.5 1.7 0.8 10.0 27.0 13.33 brown trout 0.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.5 1.0 0.5 0.6 0.0 0.04 black crappie 20.8 1.4 3.3 8.0 7.3 3.0 47.4 10.5 3.4 0.0 0.0 0.0 0.0 0.0 208.0 1.35 bluegill 823.1 832.9 776.3 570.5 174.8 335.1 444.0 336.9 85.0 358.8 11.0 30.7 15.2 32.0 25.0 40.06 eastern creek chubsucker 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.08 chain pickerel 18.6 0.8 2.6 5.0 0.0 0.0 0.0 0.0 0.0 25.7 3.3 12.3 2.7 5.1 0.0 0.09 hybrid/green sunfish 5.9 0.0 0.0 0.0 0.0 0.8 6.9 4.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0

10 golden shiner 3.2 0.0 12.0 7.9 2.3 0.0 0.9 43.5 0.0 12.3 3.5 11.3 5.6 5.0 19.0 32.011 largemouth bass 72.4 84.7 117.4 87.0 151.9 163.4 164.7 176.0 146.6 55.8 14.2 14.2 11.4 6.2 85.0 18.712 pumpkinseed 87.8 97.2 94.6 51.6 12.6 12.9 133.6 34.9 11.5 18.5 31.0 46.0 17.6 25.0 78.0 210.713 rockbass 158.4 109.4 116.3 56.9 0.0 0.0 0.0 0.0 0.0 2.5 24.5 94.0 11.9 32.0 15.0 36.014 rainbow trout 8.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.015 smallmouth bass 80.1 24.7 21.8 17.5 0.0 0.0 0.0 0.0 0.0 5.0 16.0 6.1 9.0 4.9 55.0 21.316 spottail shiner 13.1 0.7 0.0 12.3 0.0 0.0 0.0 0.0 0.0 0.0 3.0 12.7 0.0 0.0 0.0 0.017 tesselated darter 2.3 1.4 15.2 13.1 0.0 0.0 0.0 0.0 0.0 0.0 1.0 10.0 4.0 6.0 0.0 0.018 tiger muskie 0.5 0.0 0.0 0.0 0.4 1.5 0.9 0.7 2.5 0.0 0.0 0.0 0.0 0.0 0.0 0.019 walleye 0.0 4.7 2.6 3.4 1.9 0.8 0.0 2.0 3.7 0.0 0.7 1.5 1.2 1.4 21.0 0.020 white sucker 7.2 0.0 2.2 4.4 2.3 0.0 4.3 7.9 3.4 0.0 28.0 8.7 10.4 11.0 0.0 16.021 yellow perch 379.6 59.0 77.2 87.7 11.4 46.1 7.8 29.0 24.3 186.3 26.0 22.0 7.2 7.1 373.0 269.3

Saratoga (Northeast shoreline) Lodge (Savannah Dhu-Private) Otsego

ALL FISH PSD/RSDTotal Collected # < stock size (130mm) ≥ stock size (130mm) ≥ quality size (200mm) ≥ preferred size (250mm) ≥ memorable (350mm) ≥ trophy (380mm) PSD RSD

black crappie 46 37 9 1 0 0 0 n/a n/aprey # < stock size (80mm) ≥ stock size (80mm) ≥ quality size (150mm) ≥ preferred size (200mm) ≥ memorable (250mm) ≥ trophy (300mm)

bluegill 1819 1593 226 62 19 1 0 27.4 8.4prey # < stock size (80mm) ≥ stock size (80mm) ≥ quality size (150mm) ≥ preferred size (200mm) ≥ memorable (250mm) ≥ trophy (300mm)

pumkinseed 194 40 154 34 6 0 0 22.1 3.9prey # < stock size (100mm) ≥ stock size (100mm) ≥ quality size (180mm) ≥ preferred size (230mm) ≥ memorable (280mm) ≥ trophy (330mm)

rockbass 350 65 285 19 1 0 0 6.7 0.4predator # < stock size (150mm) ≥ stock size (150mm) ≥ quality size (230mm) ≥ preferred size (300mm) ≥ memorable (380mm) ≥ trophy (460mm)

brown trout 2 0 2 2 2 1 0 n/a n/apredator # < stock size (250mm) ≥ stock size (250mm) ≥ quality size (380)mm) ≥ preferred size (510mm) ≥ memorable (630mm) ≥ trophy (760mm)

chain pickerel 41 23 18 5 1 0 0 27.8 5.6predator # < stock size (200mm) ≥ stock size (200mm) ≥ quality size (300)mm) ≥ preferred size (380mm) ≥ memorable (510mm) ≥ trophy (630mm)

largemouth bass 160 141 19 14 7 0 0 n/a n/apredator # < stock size (200mm) ≥ stock size (200mm) ≥ quality size (330mm) No published value

rainbow trout 18 0 18 17 n/a n/apredator # < stock size (180mm) ≥ stock size (180mm) ≥ quality size (280mm) ≥ preferred size (350mm) ≥ memorable (430mm) ≥ trophy (510mm)

smallmouth bass 177 91 86 8 1 0 0 9.3 1.2predator # < stock size (350mm) ≥ stock size (350mm) ≥ quality size (5300mm) ≥ preferred size (710mm) ≥ memorable (860mm) ≥ trophy (1120mm)

tiger muskie 1 0 1 1 1 1 0 n/a n/apredator # < stock size (130mm) ≥ stock size (130mm) ≥ quality size (200mm) ≥ preferred size (250mm) ≥ memorable (300mm) ≥ trophy (380mm)

yellow perch 839 738 101 32 16 3 1 31.7 15.8

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Table 10. Calculations to determine the predator-prey PSD relationship Woodridge Lake 2013 and 2014.

Table 11. Accepted Stock Density Index Ranges for Balanced Fish Populations (Willis, Murphy and Guy, 1993).

Species PSD RSD-preferred RSD-memorable Reference Largemouth Bass 40-70 10-40 0-10 Gabelhouse (1984) Bluegill 20-60 5-20 0-10 Anderson (1985) Crappies (Midwest) 30-60 >10 Gabelhouse (1984) Yellow Perch 30-60 Anderson and Weithman (1978) Table 12. Stock Density Index Objective Ranges for Largemouth Bass and Bluegill under Three Different Management Strategies (Willis, Murphy and Guy, 1993).

Largemouth Bass Bluegill Management Option PSD RSD-preferred RSD-memorable PSD RSD-preferred

Panfish 20-40 0-10 50-80 10-30 Balance 40-70 10-40 0-10 20-60 5-20 Big Bass 50-80 30-60 0-25 10-50 0-10

PREY SPECIES2013 2014 2013 2014 2013 2014 2013 2014

black crappie 46 148 37 127 9 127 1 21bluegill 1796 1735 1593 1421 203 240 39 74pumkinseed 172 126 40 14 132 58 12 54yellow perch 832 576 738 342 94 194 25 40TOTAL 2846 2585 2408 1904 438 619 77 189PREY PSD 18% 31%

PREDATOR SPECI2013 2014 2013 2014 2013 2014 2013 2014

rockbass 350 282 65 28 293 207 52 47brown trout 2 12 0 0 2 12 0 0chain pickerel 16 81 16 33 23 19 7 29largemouth bass 136 154 136 119 22 25 21 10rainbow trout 18 4 0 0 18 4 0 0smallmouth bass 155 134 91 59 64 52 10 23tiger muskie 1 1 0 0 1 1 1 1TOTAL 678 668 308 239 423 320 91 110PREDATOR PSD 26% 34%

Total Collected # < stock size ≥ stock size ≥ quality size

Total Collected # < stock size ≥ stock size ≥ quality size

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Figure 5. Proportional stock density Tic-Tac-Toe grid showing predator-prey relationship adapted from Kohler and Hubert (1999).

“X” indicates value of predator-prey PSD, illustrating the predator-prey relationship in Woodridge Lake

for the Fall 2013 and 2014. The predator-prey PSD grid above indicates the fishery of Woodridge Lake is dominated by small, stunted prey with overfishing of predators. Overfishing is not the cause of the low predator PSD in Woodridge Lake, low largemouth bass abundance (possibly due to environmental factors/management activities such as drawdown), are driving this low predator PSD. Figure 6. Woodridge Lake Bluegill Length Frequency Distribution highlighting year classes. Text box indicates many fisheries studies do not quantify fish that are less than stock length.

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This electrofishing survey was conducted in the early fall. There are several things that are important to note about when and how this electrofishing sample of fish was collected. First, netters were instructed to make every attempt to catch all fish. Therefore, the netters at the front of the boat were supposed to make the same effort to catch a 50mm bluegill as a 1000mm tiger muskie. Second, this survey was done after centrarchid nesting, when Young of the Year (YOY) panfish are present in great numbers. It is likely that a similarly designed study, conducted in spring, would yield much lower catches of sunfish.

These data indicate that bluegill catch per unit effort (CPUE) is very high in Woodridge Lake. In fact this lake had one of the highest CPUE of bluegill (2013=823/hr & 2014=846/hr) that we have seen. Milfoil and bluegill enjoy a mutually beneficial relationship. Dense milfoil produces a nice monoculture that makes it very difficult for roving sunfish predators (like largemouth bass) to see, pursue and catch bluegill. Thus, bluegill have a predation refuge in milfoil. Herbivores of milfoil may be negatively impacted by these bluegill. Bluegill are invertebrate pickers, particularly small bluegill. They slowly move through milfoil, ingesting insects that they pick from the tips and stems of the plant. We know this because when examining bluegill stomachs for evidence of insectivory, we find milfoil that has been eaten incidentally, suggesting the fish pick plant material when they ingest an insect.

Figure 7. Photograph of a bluegill hybrid.

Bluegill (Lepomis macrochirus) prefer shallow, vegetated habitats and warm water. They spawn in the late spring-early summer once the water reaches 70 °F (Smith 1985). They are opportunistic feeders and eat many aquatic insects, but are known to prey on other fishes’ nests, notably largemouth bass (Micropterus salmoides) (Werner 2004). Previous fish surveys found abundant bluegill, but did not collect robust information on YOY bluegill. The bluegill population structure has remained relatively consistent in the lake from Fall 2013 (1819 fish total) to Fall 2014 (1735 fish total). However, the peak of

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the YOY length frequency has moved slightly to the right, indicating slightly larger young-of-year (figure 9). Average bluegill length was 54mm in 2014 compared to 50mm in 2013, illustrating this slight shift. Figure 8. Length Frequency (L-F) Distribution of Woodridge Lake Bluegill collected by night boat electrofishing during Fall 2013 and 2014.

Figure 9. Length Frequency Overlay for 2013 and 2014 Bluegill

A close relative of bluegill, pumpkinseed (Lepomis gibbosus) also prefer shallow, vegetated habitats with warm water. They spawn in early summer once the water is above 60°F (Smith 1985). They are opportunistic feeders and eat aquatic insects, invertebrates, mollusks and occasionally small fish (Werner 2004). Abundance of pumpkinseed collected in this survey, is comparable to previous studies. The pumpkinseed community experienced a reduction of small individuals (72 fish below quality size, 150mm) in Fall 2014 compared to 2013 (209 fish below quality size, 150mm).

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Figure 10. Length Frequency (L-F) Distribution of Woodridge Lake Pumpkinseed collected by night boat electrofishing Fall 2013 and 2014.

Black crappie (Pomoxis nigromaculatus) prefer clear water rich with aquatic plants. They spawn in late summer when the water is 68°F (Smith 1985). Forage includes small fish and various invertebrates; diet also includes plankton for the first few years. More crappie were collected in 2014 year than previous studies. A noticeably higher amount of smaller, young fish were captured and triple the total amount of crappie were collected in 2014 (148 total fish) than in the previous year (46 total fish). This is a great sign that crappie may be increasing and may support an increased recreational fishery for this highly desirable species.

Figure 11. Length Frequency (L-F) Distribution of Woodridge Lake Black Crappie collected by night boat electrofishing during Fall 2013 and 2014.

When the length frequency distributions (Figure 12) for black crappie from Fall 2013 and Fall 2014 are overlaid, the difference is noticeable. It is difficult to pinpoint the specifics of this shift, but likely correlated to less significant reservoir drawdowns increasing spawning success. Continued monitoring of both the annual drawdowns and black crappie population are required to better understand if this is the case or determine other potential sources that are positively affecting this species.

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Figure 12. Length Frequency Distribution of Woodridge Lake Black Crappie comparison from surveys during Fall 2013 and 2014.

Hybrid sunfish (Lepomis sp.) were collected in shallow weedy water. Their origin and life history is a complete mystery. Similar hybrids were collected by the CT DEP in 2012 with similar abundance and sizes found. The hybrid sunfish community remained unchanged with similar sized fish collected in Fall 2014 compared to Fall 2013. All fish collected were within the same size with no smaller fish, indicating spawning likely does not take place and these are in fact sterile hybrids that were likely introduced from stocking and cannot naturally sustain, although this is speculation.

Figure 13. Length Frequency (L-F) Distribution of Woodridge Lake Hybrid Sunfish collected by night boat electrofishing during Fall 2013 and 2014.

Yellow perch (Perca flavescens) prefer weedy littoral habitat. Previous surveys found similar trends in yellow perch populations with an abundance of smaller fish, but the 2014 did not collect as many perch as the Fall 2013 survey. Less yellow perch were collected in the Fall 2014 survey (576 total fish, 839 total fish in 2013), particularly smaller sized young of the year fish. Good numbers of catchable fish are still present and will hopefully improve. Perch are a popular panfish.

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Figure 14. Length Frequency (L-F) Distribution of Woodridge Yellow Perch collected by night boat electrofishing during Fall 2013 and 2014.

The chain pickerel (Esox niger) inhabits the shallow weedy areas of the lake. Chain pickerel typically spawn shortly after ice out, when water reaches 45-55°F but can withstand water temperatures of up to 85 °F (Smith 1985). Chain pickerel are opportunistic predators and feed on fish and crayfish as adults. As juveniles, pickerel mostly forage on small insects and crustaceans. Forty-one (41) chain pickerel were captured during the 2013 survey; an insignificant increase from the 31 chain pickerel captured in 2009.

Figure 15. Length Frequency (L-F) Distribution of Woodridge Lake Chain Pickerel collected by night boat electrofishing during Fall 2013 and 2014.

Twice as many chain pickerel were caught in Fall 2014 (39.5/hr) than in Fall 2013 (18.6/hr) with many more smaller, young fish entering into the population. As an early spring spawner, reducing drawdowns may increase their success and recruitment. Shown below is a comparison of Fall 2013 and Fall 2014 where the increase in the numbers and diversity of size classes are displayed. As a predator that thrives in shallow, weedy parts of the lake where small bluegill are often excessive, an increase in pickerel can put desirable predation pressure on bluegill. Continued monitoring of the relationship between chain pickerel and bluegill populations is important and management should work to support a healthy chain pickerel population if bluegill populations decline.

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Woodridge Lake Chain Pickerel L-F Fall 2014 (39.5/hr)

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Figure 16. Length Frequency Distribution of Woodridge Lake Chain Pickerel comparison from surveys during Fall 2013 and 2014.

Largemouth Bass (Micropterus salmoides) are a very popular gamefish that prefer warm vegetated shallows of lakes. Spawning occurs in early summer in 1-4ft of water (Smith 1985). Nests are constructed in close association with weedy habitats over sandy substrate. Adults will guard the nest, even after fry hatch, to defend from predation. They are opportunistic predators and prey on other fish, crayfish, and anything else they can fit into their mouths. While more largemouth bass were collected in 2014 compared to previous years, fish were small with few larger size over 14” (<20). There is a mystery here to solve with the low catch of sizable largemouth bass. In a lake such as Woodridge, largemouth will dominate (if not extirpate) smallmouth bass. This survey collected only 19 largemouth bass greater than stock size (200mm), which is not sufficient to calculate PSD. Figure 17. Length Frequency (L-F) Distribution of Woodridge Lake Largemouth Bass collected by night boat electrofishing during Fall 2013 and 2014.

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Smallmouth bass (Micropterus dolomieu) prefer clear water and rocky substrate. They spawn in spring constructing nests when the water reaches 62°F. Nests are sculpted from gravel and small rocks in 3-20ft of water (Smith 1985). Like largemouth, they are opportunistic predators, but limited to smaller prey from the reduced size of their mouth. Populations have been continually increasing from 2008 to present and a variety of different size classes exist; they appear to be doing very well. As stated previously, smallmouth are more abundant and have a larger average size than largemouth, a uncommon occurrence in most lakes. The size structure of the smallmouth population is more desirable than largemouth. Figure 18. Length Frequency (L-F) Distribution of Woodridge Lake Smallmouth Bass collected by night boat electrofishing during Fall 2013 and 2014.

Rockbass (Ambloplites rupestris) are typically found in sections of the lake with a rock or gravel bottom. Rockbass spawn from mid-May to mid-June when water temperatures reach 65-70°F (Smith 1985). The males build nests out of the gravel substrate and defend the nest when eggs and young are present. Depending on their size, rockbass eat anything from microscopic plankton and small insects to fish and crayfish when larger. The 2013 survey yielded a large increase in rockbass catch (298) from 2009. Rock bass numbers remained relatively stable between Fall 2013 and Fall 2014 with an increase in smaller, young of the year fish similar to other panfish species.

Figure 19. Length Frequency (L-F) Distribution of Woodridge Lake Rockbass collected by night boat electrofishing during Fall 2013 and 2014.

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Rainbow trout (Onchorynchus mykiss) are intolerant of water temperatures above 70°F. Rainbow trout in lakes require a thermal refuge in summer; this is usually found in deep well oxygenated water (Woodridge does not support such habitat in summer). Rainbow trout spawn in early spring in flowing water, without access to a suitable river they will not reproduce in lakes. Rainbow trout primarily forage on small insects and crustaceans. Large rainbows are known to forage occasionally on small fish. Between 2009 and 2013 there was a change in the rainbow trout population of Woodridge Lake. The rainbow trout increased from 0 individuals captured in 2009 to 17 individuals in 2013. Less rainbow trout were caught in Fall 2014 than in Fall 2013. No smaller, younger fish were collected demonstrating the dependence of the fishery on annual stocking. Similar sized fish were caught in both years. This is no secret. Trout in Woodridge are a put-and-enjoy fishery, with no expectation of long-term survival or reproduction and recruitment.

Figure 20. Length Frequency (L-F) Distribution of Woodridge Lake Rainbow Trout collected by night boat electrofishing during Fall 2013 and 2014.

Similarly, Brown trout (Salmo trutta), like rainbow trout do not tolerate water temperatures above 70°F and it is unlikely could sustain in the lake without annual stocking. They spawn in the fall in tributary streams and are very aggressive predators eating mostly smaller fish and large invertebrates. They are more nocturnal than rainbow trout. We only collected 2 brown trout in Fall 2013 (301mm and 426 mm), but collected a total of 12 in Fall 2014. Again, trout should be viewed as a put-and-enjoy fishery. The brown bullhead (Ameiurus nebulosus) is a tolerant bottom oriented species that prefers standing waters. Bullhead can withstand winter temperatures by burying themselves in a muddy substrate until spring. Brown bullheads spawn in late spring to early summer when water temperatures are between 62-72°F. These fish are omnivorous, using their barbels to locate crustaceans, insect larvae, plant material, small fish, and crayfish. There was no significant change in brown bullhead populations between 2013 and 2014.

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Figure 21. Length Frequency (L-F) Distribution of Woodridge Lake Brown Bullhead collected by night boat electrofishing during Fall 2013.

Yellow bullhead were collected for the first time in Fall 2014. Similar to brown bullhead, they are a very hardy, bottom oriented species that eat a variety of different prey items. They can be distinguished from brown bullhead by their yellow barbels where brown bullhead have brown colored barbels.

Figure 22. Length Frequency (L-F) Distribution of Woodridge Lake Yellow Bullhead collected by night boat electrofishing during Fall 2014.

The spottail shiner (Notropis hudsonius) is a common minnow in large clear lakes. Spawning takes place in the summer during either June or July over a sandy bottom, no nest is constructed. The diet of spottail shiner includes; zooplankton, algae, insects, and small fish. The 2009 survey did not capture any spottail shiners, 29 individuals were collected in this 2013 survey.

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Figure 23. Length Frequency (L-F) Distribution of Woodridge Lake Spottail Shiner collected by night boat electrofishing during Fall 2013.

No spottail shiner were collected in Fall 2014, but it is likely they are still in the lake.

Golden shiner (Notemigonus crsyoleucas) prefer clear calm water with plenty of aquatic vegetation. Spawning occurs from May to August over aquatic vegetation when the water temperatures exceed 68°F. Golden shiners typically school together and forage mainly on zooplankton, insects and filamentous algae. There was no significant change in golden shiner abundance between 2009 and 2013. Golden shiner were also collected in the Fall 2014 survey, but did not differ significantly from the Fall 2013 survey.

Figure 24. Length Frequency (L-F) Distribution of Woodridge Lake Golden Shiner collected by night boat electrofishing during Fall 2013 and 2014.

Tessellated darter (Etheostoma olmstedi) are typically found in rivers & stream habitats, but can survive in reservoirs. They prefer rocky substrate and spawn under rocks between April and May. They forage on microscopic crustaceans and other small invertebrates (Werner 2004). This is the first time they have been collected in Woodridge, but they tend to be difficult to catch. More individuals were collected in the

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2014 survey than in the 2013 survey, but their contribution to the fishery is minimally significant. Their presence usually indicates good water quality.

Figure 25. Length Frequency (L-F) Distribution of Woodridge Lake Tessellated Darter collected by night boat electrofishing during Fall 2013 and 2014.

White sucker (Catostomus commersoni) are a very adaptable, bottom-oriented species found in variety of different habitats including lakes, rivers and streams. They spawn in tributary streams of lakes and reservoirs in April or May. They forage on various crustaceans, mollusks, and snails and are not detritivores as many anglers believe (Wagner 2004). The white sucker population had no significant changes in average size or abundance from previous surveys.

Figure 26. Length Frequency (L-F) Distribution of Woodridge Lake White Sucker collected by night boat electrofishing during Fall 2013 and 2014.

Two new species of fish were collected in this survey that have not been recorded to our knowledge in Woodridge Lake. They include the blacknose shiner (10 fish total, 4.9/hr) and channel catfish (14 fish total, 6.8/hr). The blacknose shiner (Notropis heterolepis) is a small (<5”) minnow-like fish that prefers

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clean water with weedy vegetation. Their contribution to the fishery is minimal, but they are suitable forage for many gamefish and their presence indicates that the lake has good water quality.

Channel catfish (Ictalurus punctatus) are a hardy bottom feeding gamefish that forages on a wide variety of prey. They survive in many different conditions and spawn in late spring-early summer. They are more of a pelagic predator than most give them credit for. Chanel cats are predators more than scavengers. We believe that channel catfish were recently stocked in Woodridge Lake in 2014 and are a good addition to the fishery.

Three other species that were not collected in the 2013 survey, but found in previous studies, were captured in 2014. They include brook silverside (2 fish total, 1/hr), redbreast sunfish (17 fish total, 8.3/hr) and walleye (1 fish total, 0.5/hr). Brook silverside are an open water planktivore that are excellent forage for a variety of predator species. While only 1 walleye was captured, it was an adult sized individual so this provides some evidence that they still exist in the lake and that stocking in the past has led to a modest fishery. We recommend continued stocking of walleye.

Conclusion & Recommendations

The fishery of Woodridge Lake is good. There is good angling opportunity for trout, small- and largemouth bass, tiger muskie, chain pickerel, large panfish and memorable size black crappie. The smallmouth bass population is healthy with many individuals of preferred size and larger. Both chain pickerel and black crappie had noticeable increases of smaller individuals from 2013 to 2014 which will add to the warm water fishery. Fishing pressure is light and seasonal, with many older fish that attain a large size. There are many lakes that would envy the fishery at Woodridge.

However, milfoil management strategies (particularly water level manipulation) may disrupt the natural reproduction of littoral zone fishes such as largemouth bass. Bluegill were abundant, rivalling the highest CPUE’s of any lake that we have encountered in the Northeast. Even after two years of sampling, their numbers remained relatively unchanged and stable. We recommend continued bluegill control for increased herbivory on milfoil.

Largemouth bass and bluegill have a love/hate relationship. Largemouth bass are usually the top predator in any system they exist. Bluegill are the only species of fish (baitfish) known to expand in population in the face of largemouth bass predation. When bluegill are overly abundant (stunted) and bass are too few, bluegill limit largemouth recruitment by robbing bass nests of eggs and fry. When largemouth bass are abundant (and stunted) they over-eat the bluegill. In Woodridge it appears that the bluegill are on top, demonstrated by the high CPUE of bluegill, small bluegill size, low CPUE of largemouth bass and higher CPUE of smallmouth bass. In several smaller, New York State lakes, we have witnessed largemouth extirpate smallmouth. In fact, this phenomenon is common in most lakes but not so in Woodridge.

No walleye were captured in the 2013 electrofishing survey and only a single individual was collected in 2014, which may result from either (1) the walleye are not there or (2) they were in deeper water during our collection. In either case, our recommendation is to stock pond or fall fingerling walleye to increase predation on bluegill. Consider stocking the walleye at night to avoid excessive predation by smallmouth, largemouth, perch, pickerel and rockbass. Losses of newly stock walleye can be heavy in the first 24-hr after stocking as walleye are disoriented (Cornwell, 2005).

Many questions have arisen from the WLPOA members about water level manipulation (drawdown). Specifically: Does the drawdown harm littoral zone fishes? This is a difficult question to answer and could be the focus of extensive research that may take years to answer. But as a so called “expert” you

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are asking my opinion. So here is the answer: Yes. The drawdown strategy is intentionally disturbing the littoral zone.

A natural littoral zone generally has: (1) a relatively stable water level (2) sunlight penetration to the bottom where photosynthesis exceeds respiration (3) a good mix of stable of inorganic and organic sediment. The stable water level allows deposition of fine material and quality organic debris that plants need to grow. As the littoral of Woodridge goes up and down, the upper shores are left dry and sterile (and frozen) and quality organic debris maybe washed away (Moss, 2010). Littoral zone fish need this stability to carry out life functions (like spawning). Greater littoral fluctuation translates to a poor littoral fishery. An extreme case is the New York Power Authority in Blenheim NY. This reservoir’s water level fluctuates 40 feet a day, and has no littoral stability. There are no rooted plant, no attached algae, no soft sediment deposition and no littoral fish. The poor littoral fishery is a direct result of extreme littoral instability.

After two years of study in Woodridge, it appears that in the past largemouth (not 2013) have experienced poor recruitment from some environmental disturbance (like a drawdown). This has given bluegill and smallmouth an advantage and is totally uncommon in my experience.

The fishery did not change significantly from 2013 to 2014 based on the results of our data. In fact, this is one of the most consistent year-to-year surveys we have ever seen. Catch rates are similar between years within most species. It will take more surveys to monitor and to better understand the existing dynamics and relationships taking place within the lakes ecosystem. More young of the year and overall larger fish were recorded for chain pickerel and black crappie as well as larger bluegill and smallmouth. While these are only preliminary results based on two years of sampling, this is a good sign that reduced drawdowns can improve the fishery. Continuing to lessen the severity of winter drawdowns is encouraged over several years, but this will not cause instantaneous results. Lake stability generally equates to a stable fishery.

The fishery is not harmed to a point where there is cause for significant alarm, but decreasing drawdowns will likely benefit the fishery if that is an important goal to the WLPOA. Efforts should be made to have the lake full by April 1st. This will likely give plenty of opportunity for most littoral spawners to be successful somewhere in the lake. Since the majority of the fish species are littoral spring spawners, reducing drawdowns will benefit many important species in the fishery, not just a few individuals.

Additional monitoring will strengthen the existing scope of knowledge on Woodridge Lake’s fishery and management. Fisheries naturally fluctuate from year to year with some years having more smaller fish and others see an abundance of larger fish collected. To better define how the fishery naturally fluctuates from year to year and noting changes in the lake related to drawdowns, further studies should take place to differentiate the effects of the two.

SUNY Cobleskill will obtain raw electrofishing data from previous studies to create a historic fisheries management database. WLPOA should consider retaining a long-term fisheries consultant. Moving forward, WLPOA should write contracts with fisheries consultants where the consultant provides raw data as well as an annual report. This will allow current consultant to process data anyway they chose. WLPOA should specify that consultant collect data that includes young-of-year sunfish. Sunfish YOY (particularly bluegill) may foil biocontrol strategies where increased milfoil herbivory is the goal.

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References

Aquatic Environmental Consultants. 2009. Lake Survey Woodridge Lake. P.O. Box 37, Scotland, PA, 17254.

Connecticut Department of Environmental Protection. 2008. Fisheries Survey of Woodridge Lake.

Connecticut Department of Environmental Protection. 2012. Fisheries Survey of Woodridge Lake. Cornwell, M.D. 2005. Walleye re-introduction to Otsego Lake: Re-establishing a fishery and subsequent

influences of a top predator. Occasional Paper No. 40. SUNY Oneonta Biological Field Station 5838 State Highway 80, Cooperstown, New York 13326. pp.7-20.

ENSR International. 2001. A fisheries investigation of Woodridge Lake, Goshen, CT. ENSR

International, 11 Phelps Way, P.O. Box 506, Willington, CT 06279-0506 Kohler, C.C. and W.A. Hubert. 1999. Inland Fisheries Management, 2ndedition. American Fisheries

Society, Bethesda, Maryland. pp. 182-183.

Lord, P.H. & T.N. Pokorny. 2013. Woodridge Lake Eurasian watermilfoil (Myriophyllum spicatum) herbivorous insect impacts. SUNY Oneonta Biological Field Station 5838 State Highway 80, Cooperstown, New York 13326. 67p.

Moss, B. 2010. Ecology of Freshwaters, 4th ed. Wiley Blackwell, 111 River St. Hoboken, NJ, 07030. Pp.

216-234.

Water Resource Services. 2012. Woodridge Lake summary report.

Water Resource Services. 2012. Woodridge Lake summary report.

Willis, D.L., B.R. Murphy and C.S. Guy. 1993. Stock density indices: development, use and limitations. Reviews in Fisheries Science. 1:203-222.

Smith, C. L. 1985. The Inland Fishes of New York State. The New York State Department of Environmental Conservation. Albany. pp. 1-522.

Werner (2004). Freshwater Fishes of the Northeastern Unites States, A Field Guide. Syracuse University Press, Syracuse, NY 13244. 335p.

Zale, A.V., D.L. Parrish and T.M. Sutton. 2013. Fisheries Techniques, 3rd Edition. American Fisheries Society, Bethesda, Maryland. pp.637-676.