Tuesday, September 11, 2018

Clove Lake Survey

Bureau of Fisheries Technical Brief #2018008

Clove Lake is a narrow, shallow 10 acre lake located in Clove Lake Park in northern Richmond County (Staten Island), formed in the 19th century by damming a small brook. The largest of a chain of three connected lakes, Clove Lake is popular with anglers, but all the lakes have access. Largemouth bass, sunfish, and brown bullhead are the most common species in the lake, and are most often targeted by anglers. The lake was surveyed in Fall 2017 by boat electrofishing following the Bureau of Fisheries Black Bass and Sunfish Sampling Manual (Brooking et al. 2018) to assess bass, panfish, and bullhead populations. Due to shallow water, large sections of the shoreline were unreachable and total on-time during the survey was relatively short (36 min).
A pie chart representing the percentage of Catch by Species
A total of 704 fish from 5 species were captured (common carp were also observed). Nearly 80% of those were bluegill and pumpkinseeds. Only 6 largemouth bass were captured, less than 1 percent of the total (Figure 1). The total largemouth catch/hour (CPUE) of 9.89 (Table 1) is low for similar sized lakes in New York State. However, 5 out of 6 were quality size or larger resulting in a PSD of 83.3. Adult bass relative weight was a high 126, indicating that the few bass present were in good, even fat, condition. This is not surprising given the abundant forage in the lake. In contrast, panfish were generally small, with low PSDs of 1.1 for bluegill and 0 for pumpkinseed.
The presence of few but large bass combined with many small panfish, shiners, and bullheads suggests a prey overbalanced lake. The reason, however, is unclear. Bass exploitation is low thanks to the catch and release regulation, so apparently bass recruitment is being outpaced by sunfish recruitment. It's possible that anglers are pulling bass off beds, but shoreline access is not universal and there is plenty of space for nesting bass to remain unbothered. Water levels may fluctuate, and such changes might impact bass recruitment. Excess vegetation can also inflate small sunfish populations, but it can also aid young bass. Still, future management considerations should include nutrient control as a matter of general lake health. Another possibility is to include stocking smaller bass to aid recruitment, but without identifying the reason for low recruitment that might be wasteful. The last survey of this lake occurred in 2009 when bass PSD was much lower but overall numbers of all species were higher. Regular surveys may provide more insight into this system. For the moment, while the potential to catch a quality bass exists, a more balanced size profile is desirable for the angling population in this public park.
Table 1. CPUE per size categoryi for each species
Species
TotalTime (h)CPUE(fish/h; Standard Error)
All sizesAge-1≥Stock≥QualityPreferred
Largemouth bass
6
0.6110(5)-1.7(1.5)3(1.7)5(4.6)
Golden shiner700.61116(24)----
Brown bullhead680.61112(36)53(21.5)48(24)1.7 (1.5)-
Pumpkinseed
275
0.61454(214)38(4)119(27.4)--
Bluegill2840.61469(121)20(12)152(24)1.7 (1.5)-
(i) Length categories (inches) for size structure indices of largemouth bass, sunfish, and bullhead in Clove Lake
Largemouth
bass
Bluegill/
Pumpkinseed
Brown Bullhead
Stock≥8 in≥3 in≥5 in
Quality≥12 in≥6 in≥8 in
Preferred≥15 in≥8 in≥11 in



Saturday, September 1, 2018

Meadow Lake Snakehead Monitoring

Meadow Lake Snakehead Monitoring

Bureau of Fisheries Technical Brief #2017002

Meadow Lake (94.9a) is the larger of two fresh water bodies located entirely within Flushing Meadows Corona Park in Queens County, NY. The two ponds are connected by a narrow creek, while Meadow Lake, the more downstream of the two, is connected to Flushing Bay through Flushing Creek. The connection is interrupted by a tide gate which is intermittently opened by managers at the NYC Parks Department. As a result, Meadow Lake has slightly elevated salinity that typically hovers in the range of 4-7ppt and hosts a mix of estuarine and freshwater fish species. Northern snakeheads were first found in the lake in 2005, and annual NYSDEC general biological boat electrofishing surveys have documented them at low levels of abundance since then. Boat electrofishing was conducted again in 2017 to continue monitoring the northern snakehead population and assess any impacts this introduced predator may have on the native fish community.
In 2017, one 18.7in adult northern snakehead was collected in Meadow Lake, out of 285 fish from 5 species (plus eels and carp that were observed but not collected). When compared to previous years, the northern snakehead population in Meadow Lake does not demonstrate a consistent trend either positive or negative (Figure 1). Only fall electrofishing surveys are compared across years since spring surveys were not conducted regularly and demonstrated dramatically reduced catch-rates.
Figure 1: Fall CPUE (number caught/h) for important fishes in Meadow Lake from 2011-2017. Since spring surveys have very different results only autumn surveys are included.
Figure 1: Fall CPUE (number caught/h) for important fishes in Meadow Lake from 2011-2017. Since spring surveys have very different results only autumn surveys are included.
Consistent with past years, white perch were the most abundant fish collected (Table 1). 2017 also marked the third year in a row that not a single Lepomis spp. was captured in Meadow Lake. The beginning of the decline coincided with a large multi-species mortality event (cause unknown) that occurred during late summer/early fall in 2014. Also in 2014, the control board of Region 2's electrofishing boat was replaced. The new board limits the amount of voltage available for fishing. This limitation presents a disadvantage in high conductivity environments such as Meadow Lake and may also help explain why no further Lepomis have been captured. As of now there is no definitive explanation for the disappearance of sunfish from Meadow Lake surveys. Additional boat electrofishing as well as seine and trap net surveys will be conducted in 2018 to try and ascertain whether sunfish are truly absent or just difficult to catch.
Overall, there is no evidence that the snakehead population in Meadow Lake is increasing. There are also no evident impacts of snakeheads on native fish but the fish community of this system as revealed through electrofishing is not always consistent. Boat electrofishing surveys will continue annually to monitor the status of the snakehead population and its impacts.
Table 1: Percentage of individual fish by species in Meadow Lake from 2011 to 2017. Carp, eels, and snakeheads which were observed but not captured have been excluded.
Survey Year
Species2011201220132014201520162017
silverside9.451.83.233.519.81.21.1
gizzard shad3.41.52.820.71.54.320.0
brown bullhead0.00.10.00.50.01.20.4
mummichog0.00.50.30.31.75.50.0
white perch68.239.581.944.672.583.574.4
pumpkinseed*16.56.58.40.50.00.00.0
largemouth bass0.40.00.00.00.00.00.0
snakehead2.20.02.00.00.00.40.4
goldfish0.00.00.00.03.50.82.8
other0.00.00.00.00.23.10.0

https://www.dec.ny.gov/docs/fish_marine_pdf/snakeheadsnyc.pdf


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