ChesFIMS 2002 September Shoal Survey Summary Report
Sampling Dates:
17 September 2002 – 4 October 2002
Boat Used:
20’ Maycraft with a 130 hp engine
MD DNR Co-Principal Investigator:
Chief Scientist:
Phone Number:
E-mail:
Brandon Muffley
(410) 260-8284
BrandonM@dnr.state.md.us
Participating Scientists:
1. B. Muffley
MD-DNR
2. A. Sharov
MD-DNR
3. J. Mowrer
MD-DNR
4. P. Genovese
MD-DNR
5. B. Sadzinski
MD-DNR
6. A. Bolinger
MD-DNR
7. A. Jarzynski
MD-DNR
Objectives:
Alexei Sharov
8. K. Crawford
9. M. Harlinski
10. E. Pertain
11. K. Donaldson
12. H. Hornick
MD-DNR
MD-DNR
MD-DNR
UMD–College Park
MD-DNR
Obtain data on relative abundance and biological characteristics of the
bentho-pelagic fish community in the extensive shoal habitats (< 5m
depth) in the Maryland portion of Chesapeake Bay. Collect and preserve a
sub-sample of catch for dietary analysis.
Area of Operation: From the MD line (approximately 37.5ºN) to just south of the
Aberdeen Proving Grounds (39.15ºN).
Type of Operations: Conducted 6-minute bottom-water trawls and recorded a number
of environmental and water quality variables at 120 stations in 9
different strata in Chesapeake Bay (Table 1, Figure 1).
Data / Specimens Collected: Collected 3,060 fish (over 117 kg) from 25 different
taxonomic categories (Table 1). Preserved (EtOH) samples
from approximately 14 stations where targeted species
were present in the catch. Environmental and water quality
data recorded at each station.
Damage to Gear:
The same trawl was used the entire sampling period without any
damage to the gear.
Figure 1. ChesFIMS 2002 September shoal survey station locations.
Cruise Summary:
We started the shoal portion of the survey on Tuesday, September 17 and finished
on Friday, October 4, 2002. This time period included 14 working days, 12 of which
were spent sampling. The strata were not sampled in any pre-determined or systematic
order but were sampled on particular days based upon weather conditions and crew
availability. Once at a particular location, the order in which the stations were sampled
was not pre-determined but based upon weather conditions and tide state.
Overall, the September survey was successful and all objectives were met or
exceeded. Based upon survey design (random with allocation proportional to strata size),
it was determined that 112 stations were required to be sampled and we were able to
sample 120 stations (Table 1). We collected fish from 109 of the 120 stations (91%)
sampled. Accounting for all species and all strata, the overall catch tow-1 was 25.50 ±
38.77 (mean ± S.D., range 0 – 254). As in July, these catch estimates are lower than the
previous years estimates with an overall catch tow-1 of 43.24 ± 49.18 in September 2001.
The Patapsco and Little Choptank strata had the highest catch tow-1 (mean 58.22 ± 61.03
SD, 50.67 ± 79.91, respectively), while the Severn/South and Chester strata had the
lowest catch tow-1 estimates (mean 5.00 ± 5.89 SD, 5.56 ± 11.88, respectively). In total,
3,060 fish were caught from 25 different taxonomic categories with a total catch weight
of more than 117 kg. Although not as dramatic as the July comparison, the total number
of fish caught in September 2002 was lower than September 2001 (3,060 in 2002
compared to 4,627 in 2001), but the total biomass was higher in 2002 (over 117 kg)
compared to 2001 (82 kg).As in May and July, bay anchovy (Anchoa mitchilli) was the
most common fish encountered throughout the bay and accounted for over 1/3 of all the
fish caught. The blue crab closely followed and was found in all strata but was dominant
in Choptank Tangier Sound catches. Weakfish (Cynoscion regalis), spot (Leiostomus
xanthurus), and the northern kingfish (Menticirrhus saxatilis) were common in the
Pocomoke and Tangier Sound catches, while white perch (Morone americana) and
striped bass were common north of the Bay Bridge in the Patapsco and Chester strata. A
summary of the biological characteristics of all species caught during the September 2002
survey is provided in Table 2. We also compared mean catch tow-1 indices for a few
common species between May, July, and September 2002 for a monthly comparison
(Figure 2), and between September 2001 and 2002 surveys to provide some connection
between last years results (Figure 3).
At the end of each trawl, surface and bottom YSI measurements (temp, DO, and
salinity) were taken at every station. Salinity ranged from a high of 20.8 in Pocomoke
Sound, to a low of 11.8 in the Patapsco stratum. Even though this was our lowest reading
for September, salinity in the Patapsco stratum has increased each sampling period and
was much higher than readings found in May when salinity ranged from 0.9 to 4.3. and
July with a range 8.2 to 9.4. Surface DO readings were variable between strata but within
each strata DO was relatively consistent. On average, surface DO ranged from 5.0 – 8.0
mg L-1. The highest surface DO readings were found in the Patapsco stratum with a mean
surface DO of 7.8 mg L-1, while lowest DO reading were found in the Tangier and
Pocomoke Sound strata with a mean surface DO of 5.8 mg L-1. Bottom DO readings
rarely fell below 5.0 mg L-1 (2 readings, both in Tangier Sound) and were usually greater
than 6.0 mg L-1. Surface temperatures ranged from a high of 25.5 ºC to a low of 21.8ºC.
The warmest mean temperatures occurred in the Pocomoke and Tangier strata, the first
areas to be sampled.
Sampling Dates
Stratum
# of Trawls
# of Fish Caught
# of Species
9/17/02 - 10/4/02
Chester
Eastern Bay
Choptank
Little Choptank
Tangier Sound
Pocomoke Sound
Patapsco
Severn/South
Calvert Cliffs
9
9
12
9
33
20
9
9
10
50
54
192
456
1417
187
524
45
135
6
6
8
13
22
18
9
11
11
Total
120
3060
25
Table 1. Summary of the September 2002 survey sampling intensity and catch results.
Common Name
Total N
Total Weight (g)
Mean Length (mm)
S.D.
Range (mm)
American Eel
Atlantic Spadefish
Bay Anchovy
Blackcheek Tonguefish
Blue Crab
Croaker
Feather Blenny
Hogchoker
Horseshoe Crab
Lizardfish
Naked Goby
1
31
1096
16
702
155
10
56
16
16
87
185.0
640.0
826.4
97.0
68273.0
430.0
14.0
637.5
*****
1870.0
33.8
485.0
78.8
47.7
110.8
115.2
34.0
50.0
93.3
*****
262.9
39.4
*****
22.7
10.1
47.3
35.8
29.8
16.9
16.7
*****
28.8
8.5
*****
25 - 130
19 - 75
34 - 161
11 - 200
12 - 255
27 - 70
27 - 145
*****
219 - 330
22 - 55
Northern Kingfish
Northern Pipefish
Northern Puffer
Northern Searobin
Oyster Toadfish
Pigfish
Silver Perch
197
22
3
4
4
1
2
1057.0
*****
13.0
85.0
286.0
78.0
28.0
75.3
113.6
64.0
121.5
151.3
178.0
112.0
28.0
43.0
8.0
61.7
44.7
*****
22.6
21 - 191
72 - 221
56 - 72
63 - 208
114 - 215
*****
96 - 128
Skilletfish
Spot
Striped Anchovy
Striped Bass
Summer Flounder
Weakfish
White Perch
13
56
18
17
20
155
362
2.5
3505.0
52.0
800.0
3986.0
908.8
33621.4
40.2
172.7
73.3
170.1
264.9
73.7
188.8
8.5
17.1
10.9
35.3
41.6
26.7
23.4
29 - 58
152 - 250
57 - 101
114 - 255
175 - 322
38 - 185
130 - 268
Table 2. Biological characteristics of all species caught during the September 2002 survey.
Blue crab biomass based on a L-W relationship from May and July 2002 data of known length and weights
10
9
May
Mean Catch Tow -1
8
July
September
7
6
5
4
3
2
1
0
Bay
Anchovy
Blue Crab
White
Perch
Croaker
Spot
Striped
Bass
Hogchoker
Summer
Flounder
Weakfish
Figure 2. Monthly catch rate comparisons (number tow-1) for a few of the more common
species encountered during all sampling periods.
20
18
Mean Catch Tow
-1
16
Sept.-01
Sept.-02
14
12
10
8
6
4
2
0
Bay
Anchovy
Blue Crab
White
Perch
Croaker
Spot
Striped
Bass
Hogchoker
Summer
Flounder
Weakfish
Figure 3. Yearly comparison of September catch rates (number tow-1) for a few of the
most common species found during the two survey years. 2001 – 107 trawls in 4 strata;
2002 – 120 trawls in 9 strata.