Fisheries Survey of Whitney Point Reservoir
Whitney Point Reservoir Fishery Resource Summary January 2005
The Whitney Point Reservoir fishery has seen its share of highs and lows over the years and this yo-yo effect for various species continues today. The New York State Department of Environmental Conservation has monitored fish population trends by netting the lake on a yearly basis from 1984 to 1993. From 1993 to 1999 sampling effort was reduced to every third year. However, starting in 2001 sampling frequency was increased to every other year to allow for better monitoring of population trends. The following paper is a brief summary of our findings from these and other surveys.
Both the white and black crappie inhabit the reservoir but white crappie are by far the most common. Over the years the difference in abundance between white and black crappie has varied from as low as 15:1 to as many as 400:1. Year to year success of white crappie reproduction (recruitment) has varied tremendously since we began sampling in 1984. In that time we have observed seven strong year-classes, three moderate, and ten weak or non-existent year-classes (year-class refers to the year they were born). Crappie generally become vulnerable to our sampling gear at age 1 so there is at least a one year lag before we can determine if a year-class is strong or not (see table below for year-class strength). What is clear is that crappie recruitment in Whitney Point is generally boom or bust and there are very few middle-of-the-road years.
|Strong Year-classes||1983, 1985, 1987, 1990, 1991, 1997^, 2000*|
|Moderate Year-classes||1986, 1988, 1995*|
|Weak Year-classes||1984, 1989, 1992, 1993^, 1994**^, 1996^, 1998, 1999^, 2001^, 2002**|
^ based on catch of older year-classes
Bold exceptionally strong
What factors determine whether a year-class is strong or weak? This question is still open to debate in the scientific community and there are numerous factors which have been suggested including: number of adults available to reproduce; water level fluctuations in the spring; the flushing rate of a reservoir; spring water temperatures; abundance of predators (including adult crappie); winter severity; and others. Depending on the study each of these factors appears to have played a role at one time or another and it's likely that no single factor is the key. This probably is true for Whitney Point as well.
To further expand on some of the factors mentioned above lets look first at the theory that the number of adults impacts year class strength. This theory is once again being investigated by researchers and some feel it may have a strong influence on year-class strength. However, our data from Whitney Point Reservoir indicates that this may not be a factor. Two of the stronger year-classes produced, 1990 and 1991, occurred in years when the adult biomass in our sample was relatively low compared to other years. Why then may low adult biomass not be so important? Each female crappie produces, on average, about 30,000 eggs which means that a relatively small number of females can potentially produce a lot of offspring if conditions for survival are favorable. This is not to say there is no threshold number of adults which we should not drop below, but rather its likely we have never been too low in the past.
It is likely that survival of eggs and young is much more important. Large temperature swings (especially from warm to cold) have the potential to reduce survival of newly hatched fry. Extreme flooding may play a part as well, especially if large volumes of water (a high flushing rate) are quickly released when the young are relatively immobile and subject to being washed out of the reservoir. Predation by large numbers of adult and sub-adult crappie and, more recently, increased numbers of walleye may also impact survival of juvenile crappie.
At Whitney Point Reservoir we used to assume recruitment was "cyclical" and strong year-classes of fish would be produced on a every other or third year basis. However, things changed at the end of the 1980's when we observed the production of back to back strong year-classes mentioned earlier. Following that it there was a gap of six years before the next truly strong year-class came along. The term "cyclic" infers things occur at a regular interval but that just hasn't been the case and we recognize it is likely a multitude of factors which makes recruitment of crappie a "hit or miss" proposition in the reservoir.
What can we do?
Harvest restrictions - The change to a 9-inch size limit has protected crappie from angler harvest until they are Age 3. In the past most reservoir anglers started to keep crappie when they reached a length of 7.5 - 8 inches (Age 2). The main intent of the 9-inch regulation was to allow them to grow to a quality size. White crappie double their weight between the sizes of 7.5 and 9.0 inches and natural mortality (by nonhuman predators and disease) is minimal. In addition to improved size quality at harvest, the length limit serves to increase the number of adults available to spawn. Although this may not be a critical factor in year class production, it certainly can't hurt.
Log and Brush-pile Structure
Habitat improvement - Newly hatched crappie fry utilize near-shore cover. The reservoir is conspicuously lacking cover of any type but recent cooperative efforts between local sportsmen and the DEC has led to the installation of numerous brush-piles and root-wad clusters along the shoreline. This cover provides both spawning habitat for adults and refuge for newly hatched and juvenile fish. Addition of habitat is expected to continue in coming years.
Regulation Change for Walleye - As you will read below natural reproduction of walleye has been extremely prolific in recent years and the abundance of walleye has increased compared to levels in the 1980's. Walleye certainly feed upon young crappie but the extent of their impact on recruitment is unknown. One option we will have to consider if poor recruitment of crappie continues is changing the legal length limit back to 15 inches to allow for more walleye harvest.
Stocking - This is not a realistic option. The Department has no hatchery facility geared toward sunfish production of any kind and conversion of existing facilities is not feasible. Construction of a new hatchery is also out of the question given our current and anticipated budgets. Trapping and transferring of fish from other waters would be labor intensive and likely provide few fish relative to the size of Whitney Point Reservoir. Further, there really are no waters around Central New York which have a surplus of crappie available. Even if there were, users of those waters would likely be opposed to any attempts to remove a significant number of crappie from "their" lake.
Fishery Monitoring - Continue monitoring trends in abundance and year class strength on an every other year basis. Strong year-classes can be more easily identified under this sampling regime then under the every third year scenario and with time we may be able to determine what factors are playing the biggest role in determining crappie recruitment. Additional management options for improving or stabilizing crappie recruitment may than be developed.
Other Scientific Research - Continue to review the findings of other states and universities and apply these findings when appropriate.
Beginning in 1994, recruitment of walleye has been monitored annually by fall night electrofishing surveys (except for 1996). Using techniques developed in other areas, a population estimate can be calculated for young-of-year (YOY) walleye based on the number caught per mile of shoreline that is sampled. The following are population estimates of YOY walleye for all the years surveyed:
Walleye from the 1997 and 1999 year-classes have now reached the legal length limit of 18 inches and, by angler accounts, are providing exceptional fishing opportunity. Because the 1997 year-class was so large their growth in their second year was greatly reduced due too excessive competition. The 1999 year-class, on the other hand, exhibited good growth through 2003 and many individuals are now equal to or larger than their 1997 counterparts. Some fish from both these year-classes are now more than 22 inches long.
Sizeable year-classes of walleye were also produced in 2001, 2003, and 2004. Fish from the 2001 year-class have exhibited good growth and averaged 13.7 inches in the summer of 2003. They should be approaching the legal length at the end of 2005. The 2003 and 2004 year-classes, though large in number, were the smallest average size yet seen since sampling began. YOY walleye in 2004 averaged only 6.5 inches in October (compared to past average sizes closer to 8 inches) with many fish were 5.5 inches long or less. Cooler than average temperatures in both years may have contributed to the reduced growth but it almost certainly reflects a lack of forage later in the growing season. During both surveys we saw relatively few young-of-year yellow perch and almost no young-of-year crappie.
Overall, the abundance of walleye in Whitney Point Reservoir is currently higher than we have seen at any time since netting surveys began in 1984. The catch rate of walleye in gillnets in 2001 was 10 times higher than the average observed from 1984-86 and more than double the average from 1987-99. The 2003 catch rate of walleye was slightly more than half of the 2001 catch and this decline probably reflects the angler harvest that occurred as the 1997 and 1999 year-classes reached legal size. Certainly downstream migration through the dam impacts population levels in the reservoir but we don't know how important this is.
Where do we go from here?
Fishing Regulations - In October 1997 we increased the minimum length limit from 15 to 18 inches and reduced the daily limit from five to three. This change came about because our sampling data indicated that Whitney Point Reservoir walleye were growing faster than average and were reaching 15 inches before they reached their fourth birthday. Because most female walleye do not spawn for the first time until they are at least four years old it meant females were vulnerable to harvest before ever having had a chance to spawn. The increased size limit thus provides females an extra year of protection from harvest. We hoped that by increasing the spawning stock we would be able to enhance walleye recruitment. We will continue to monitor walleye abundance in the reservoir and make any changes that we feel are necessary to enhance the overall reservoir fishery.
Stocking - Since natural reproduction of walleye has been extremely successful for more than a decade there are no plans at this time to stock hatchery raised walleye in the reservoir. We will continue to monitor trends in walleye recruitment and, if necessary, recommend a stocking policy if a drastic decline in the walleye population occurs.
Population trends for other fish species are not as easily assessed due to the relatively low numbers of "other" fish that we catch. There are certainly moderate to good numbers of panfish (yellow perch, bluegill, and pumpkinseed sunfish) in the reservoir and their growth is excellent. Year after year we sample many yellow perch in the 10-13 inch size range and sunfish in the 6-8 inch size range. However, based on angler reports, and a creel survey conducted in 1999/2000, the presence of these quality sized fish in our survey does not necessarily translate into good fishing success for anglers.
Largemouth and smallmouth bass are both present in the reservoir in moderate numbers. Smallmouth used to outnumber largemouth in the past but the numbers seemed to have evened out in recent years. Growth rates of both species are good and we have sampled several largemouths over 6 pounds in recent years.
Both yellow and brown bullhead are common in the reservoir. Abundance of both species was relatively high in the 1990's but has dropped noticeably since 1999. Reasons for this decline are unknown but it is possible that walleye predation on young bullhead may be limiting recruitment. Growth rates are not known but most of the fish we collected are full-bodied and fish between 12 and 15 inches are common.
A population of channel catfish is present in the reservoir and we catch several individuals per survey. Most are in the 12 - 20 inch size range but an occasional 10+ pound fish has been caught.
Common carp generally live up to their name in Whitney Point Reservoir and can be found in substantial numbers. Although there a few big ones are around, most are in the 3 - 8 pound size range.