A ruptured pipeline caused a large spill of petroleum products above Fredericksburg, VA on March 6, 1980. Much of the oil was recovered; however, a portion of the contaminant eventually reached the Rappahannock River. The significance of the spill was magnified because it occurred during spawning of anadromous and other commerically important fishes.
A study following the spill was conducted by the Virginia Institute of Marine Science (VIMS) in the summer of 1980 in the upper Rappahannock River. The objectives as stated in the proposal were to (1) determine an index of abundance for juvenile striped bass (Morone saxatilis), alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), white perch (Morone americana) and American shad (Alosa sapidissima) in the Rappahannock River  (2) estimate relative abundance of.juveniles over~time during the period of high mortality, and (3) establish a data base of relative abundance of juvenile striped bass, white perch and alosine fishes in a portion of the Rappahannock River

Kriete, William H., Jr.

English

College of William & Mary: W&M Publish

W&M ScholarWorks Reports 1980 Index of juvenile striped bass, white perch, and alosine fishes in the Rappahannock River following the March 1980 oil spill William H. Kriete Jr. Virginia Institute of Marine Science Follow this and additional works at: https://scholarworks.wm.edu/reports  Part of the Aquaculture and Fisheries Commons Recommended Citation Kriete, W. H. (1980) Index of juvenile striped bass, white perch, and alosine fishes in the Rappahannock River following the March 1980 oil spill. Virginia Institute of Marine Science, William & Mary. https://scholarworks.wm.edu/reports/2290 This Report is brought to you for free and open access by W&M ScholarWorks. It has been accepted for inclusion in Reports by an authorized administrator of W&M ScholarWorks. For more information, please contact scholarworks@wm.edu. Report to Mason and Hanger-Silas Mason Co., Inc. Consultants Edison, New Jersey Project title: Index of Juvenile Striped Bass, White Perch and Alosine Fishes in the Rappahannock River Following the March 1980 Oil Spill Project Period: 7 July to 30 October, 1980 Prepared by Williwn H. Kriete, Jr. College of William and Mary Virginia Institute of Marine Science School of Marine Science Gloucester Point, Virginia 23062 t1r~J ;re>_,:_ I\< r :: (J' __ fo tc" 1\'/\ lf -1r_ ' \ \ r\(/) r'l ,. I ·"' • c· Index of Juvenile Striped Bass, White Perch and Alosine Fishes in the Rappahannock River Following the March 1980 Oil Spill INTRODUCTION 2 A ruptured pipeline caused a large spill of petroleum products above Fredericksburg, VA on March 6, 1980. Much of the oil was recovered; however, a portion of the contaminant eventually reached the Rappahannock River. The significance of the spill was magnified because it occurred during spawning of anadromous and other commerically important fishes. A study following the spill was conducted by the Virginia Institute of Marine Science (VIMS) in the summer of 1980 in the upper Rappahannock River. The objectiv~s as stated in the proposal were to (1) determine an index of abundance for juvenile striped bass (Morone saxatilis), aiewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), white perch (Morone americana) and American shad (Alosa sapidissima) in the Rappahannock River ' (2) estimate relative abundance of.juveniles over~time during the period of high mortality, and (_3) establish a data base of r•elative abundance of juvenile striped bass, white perch and alosine fishes in a portion of the Rappahannock River. MATERIALS AND METHODS Sampling was conducted in the Rappahannock River between Piscataway Creek (Mile 35) and Hayfield Bar (Mile 85)(Fig. 1). 3 All sampling was conducted at night to minimize the effect of varying light intensities (Loesch, Kriete, and Foell MS in review). A 5 .s m outboard vessel equipped with a pushnet, and a 5 .9 m outboard vessel towing a 4.9 m two-panel trawl were used to collect standard 5 min samples. Flowmeters were secured to the pushnet and the volume of water strained and distance covered in relation to the water column were recorded for each sample. Flowmeters were attached in the two-panel trawl as bottom conditions permitted (e.g., if no obstructions were anticipated). From these readings, average volume strained (872 m3), and average distance covered in relation to the water column (241 m) were determined. The pushnet is constructed of l.9 cm stretched mesh nylon netting in the body and 1.27 cm stretched mesh nylon netting in the cod end. The net is lashed to a 1. 5 m X 1. 5 rn rigid frame which is pushed ahead of the vessel (Kriete and Loesch 1980). The two-panel trawl is constructed of 3.81 cm stretched mesh nylon netting with a 1.27 cm stretched mesh nylon netting liner in the codend. The alosine nursery area (approximately Mile 50-85) was divided into 5-nautical mile strata. Each stratum was further divided into five 1-mile substrata. Perpendicular to this stratification, the 5-mile strata were divided into three nearly equal parts, a center section and two shoreward sections bounded by the 1.8 m depth contour lines (MLW) indicated on a navigation chart. Thus, each 5-rnile stratum was partitioned into 15 11 cells 11 (Loesch et al. 1979). Four randomly selected stations at each alternating five-mile strata beginning at Mile 50 and terminating at Mile 85 were sampled during July, August and September. 4 On each side of the river, shoreward of the 1.8 m depth con-tour, the definition of stratum resulted in 10 cells, five for each shore (Loesch et al. 1979), in the striped bass-white perch nursery area. These sites were sampled with the 4.9 m trawl which swept virtually the entire water column. Randomly selected stations, 3 to 4 per stratum from Mile 35 to Mile 60, were sampled on dates coinciding with the juvenile alosine sampling. During the September sampling, the Mile 35-40 stratum was deleted and Mile 60-65 stratum was added because of the salt wedge encroach-ment upon the freshwater and oligohaline nursery areas due to drought conditions. Tow direction in relation to current direction was randomized within each stratum for both pushnet and trawl collections. Hydrological data were collected during each of the three sampling periods (Table 1). All samples collected were preserved in l(f/o formalin and returned to VIMS for processing. Fifty specimens (when available) of each of the species of concern were measured to the nearest millimeter (fork length), aggregate weights and total number in the sample were recorded. A 11 remaining species were enumerated and aggregate weights taken. Large catches were sub-sampled, and sub-samples were expanded to reflect total catch. Catch-per-unit-of-effort (CPUE) for juvenile alewife, blueback herring and American shad from pushnet catches was determined by 5 dividing species catch by volume strained per stratum for each sampling period. Trawl CPUE for juvenile white perch and striped bass was determined by dividing species catch per stratum by the number of trawls in that stratum for each sampling period. Adults were excluded from all calculations. 'RESULTS AND DISCUSSION A total of 31,614 finfish representing 28 species, and 912 blue crabs ( Ca llinectes sap id us) were collected in 94 pushnet and trawl samples in July, August and September 1980 (Table 2). Blueback herring dominated the pushnet catches while spot (Leiostomus xanthurus) and white perch were the dominant species in the trawl samples. Drought conditions prevailed as evidenced by the occurrence of marine fishes, e.g., summer flounder (Paralichthys dentatus), spot, Atlantic croaker (Micropogonias undulatus), weakfish ( Cynoscion regalis) and Atlantic menhaden (Brevoortia tyrannus) and blue crabs in areas that are freshwater under normal conditions. Blue crabs were collected above Mile 60 in both pushnet and trawl samples, with one blue crab captured by the.pushnet at Mile 80. The salinity in the sampling areas increased steadily from July to September ultimately relocating the salt-freshwater interface above Leeds-town (Mile 52)(Table 1), Alosine Fishes Blueback herring was the dominant alosine in virtually all of the pushnet collections ( Table 3A). Dominance of this species is borne out in recent past commercial landings of adult alosines in the Rappahannock River (Loesch and Kriete 1976, Loesch et al. 1979). 6 Peak abundance of blueback herring, as indicated in pushnet collections, was during July. Catch-per-unit-of-effort (CPUE) declined in August compared to July due to natural mortality; however, CPUE increased in September compared to August. This increase may be attributed to either recruitment to the mainstream river population or sampling error in August, with recruitment being the more plausible explanation. Alewife peak abundance, as opposed to blueback herring, occurred during September (Table 3A), However, only a slight increase in CPUE was noted from July to September. As with blueback, this phenomenon may be due to recruitment. Alewife spawn earlier than blueback herring (Hildebrand and Schroeder 1928); therefore, it is reasonable to assume that peak abundance of juvenile alewife would occur earlier than that of juvenile blue-back herring. Too few American shad were collected during the three sampling periods to draw any definitive conclusions concerning abundance or mortality for this species. Peak abundance in July as indicated by CPUE for both alewife and blueback herring occurred in the stratum 70-75, In August the highest CPUE was recorded in stratum 60-65. This movement although still in freshwater is probably the beginning of the seaward migration (Loesch et al. 1979). However, the effects of 7 the drought experienced during the 1980 summer months are apparent in the CPUE of alewife and blueback in September. The highest CPUE for blueback herring occurred in stratum 70-75, and in stratum 80-85 for alewife. The lack of rainfall and the resulting encroachment of saline waters in the nursery area served to reduce the size of the alosine nursery. Further evidence of the en-croachment may be fouhd in the CPUE of alewife and blueback herring in Table 3B. (These results are used only as an illustration and should not be directly compared to those in Table 3A). Although much of the increase in CPUE in the upper strata in September relative to August is upstream movement, the possibility of recruibnent must not be discounted. White Perch and Striped Bass Trawl collections in July resulted in the highest CPUE for white perch and the only striped bass for the three sampling periods (Table 3B). The decline in CPUE for white perch from July to September is indicative of natural mortality; however, movement to avoid areas of higher salinity is a probable contribut-ing factor. The highest CPUE for white perch in July through September occurred in stratum 55-60 and similarly the next highest CPUE for white perch was reco1'ded at stratum 45-50 for all months. As noted in the sampling for alosine fishes, the effects of drought conditions are evident in the CPUE for white perch from the September sampling. Only one striped bass was collected in 46 trawls during the three sampling periods. 8 CONCLUSIONS AND RECOMMENDATIONS The lack of rainfall during the summer of 1980 produced severe drought conditions throughout Virginia .. Freshwater nursery areas utilized by anadromous fishes were greatly reduced, thus creating greater feeding competition. This, coupled with high water temperatures, may have increased mortality rates within these areas. The high mortality rate of 45% for blueback herring from July to August may not be excessive when these factors are considered. Alewife CPUE, although much lower than blueback herring, is representative of the population sampled. The precipitous decline in white perch CPUE from July to September would mean an extremely high mortality rate under normal conditions. However, given the sampling and environmental conditions, this may or may not be true. With increasing water temperature and salinity, the juvenile white perch may have either moved upstream or to deeper water and thus would be unavailable to the trawl. Only three American shad and one striped bass were captured during the three sampling periods. Speculation would lead to endless possibilities with few of sound basis. It is reasonable to assume that the number of surviving juveniles of each of the species is low. However, without background data on the adult spawning population and some measure of immediate spawning success (eggs and/or larvae), coupled with an estimate of gear efficiency, it is difficult to attribute success or failure of a year class to a single source. 9 In light of the unusual environmental conditions encountered in 1980, several recommendations should be taken into consideration. First, the survey should be repeated to allow comparison with data that more closely fits the norm. However, minor modifications and/or improvements are advised. The number of repetitions in each stratum should be increased in the trawl collections to reduce sampling error. Secondly, given environmental conditions at the time of sampling, comparison trawls must be conducted to determine gear efficiency. Lastly, the trawling should be initiated at an earlier date with increased number of sampling periods to insure coverage of juvenile mortality. Procedures for sampling juvenile alosine fishes appear to be adequate in their present form. ACKNOWLEDGMENTS I wish to thank the following people for their able assistance in field collections and associated laboratory analyses: J. Davis, E. Foell, K. Friedland, M. Hennigar, J, Owens, and J, Travelstead. J. Davis and M. Hennigar prepared the tables and made helpful comments on the text, and M. Vaden prepared the figure. LITERATURE CITED Hildebrand, S. F. and w. C. Schroeder. 1928. Fishes of Chesapeake Bay. U.S. Bur. Fish. Bull. 43 (Part I); 10 Kriete, W. H., Jr. and J. G. Loesch. 1980. Design and relative efficiency of a pushnet. Trans. Amer. Fish. Soc. Vol. 109. ( In press). Loesch, J. G. and W. H. Kriete, Jr. 1976. Biology and management of river herring and shad in Virginia. Completion Rep. 1974-76. Virginia AFC 8-1 to 8-3. Virginia Institute of Marine Science, Gloucester Point, Virginia. 226 p. Loesch, J. G., W. H. Kriete, Jr., J. G. Travelstead, E. J. Foell and M.A. Hennigar. 1979. Biology and management of mid-Atlantic anadromous fishes under extended jurisdiction. Completion Rep. NC-VA AFCS 9-1 to 9-3. Part II: Virginia Institute of Marine Science, Gloucester Point, Virginia. 204 p. Table 1. Temperature and salinity data collected in the Rappahannock River in July, August, and Septe,tber, 1980. A. Alosine sampling July River Mile Temp. (C) Sal. (%,) 80-85 30.6 (a) 64-75 31.0 0.0 50-55 30.0 0.1 B. White perch and Striped bass sampling July River Mile Temp. ( C) Sa 1. (1a,) 60-65 55-60 30.5 (a) 50-55 45-50 29.6 0.5 40-45 35-40 28.2 5.5 (a) no readings, assumed to be O.Ofo, (b) no readings, equipment failure Auoust September TemD. ( C) Sal. (%,,) 'I em p __.___J___Q__2 Sal. (%,,) 30.0 o.o 28.2 o.o 30.0 o.o 29.0 o.o 30.0 0.5 -27 .8 1.0 .Z\ugust Se2tember Te11p. ( C) Sal. (%0) Tem~_i_Q_)_ Sa 1. (%,,) (b) o.o 30.5 o.o (b) o.o 29.9 0.5 (b) 1.0 29.3 2.0 (b) 2.0 28.6 4.0 (b) 5.0 27.9 7.0 t--' t--' Table 2. Nt..'T,ber of fishes and crabs collected by pushnet and trawl in the Rappahannock River in summer of 1980~ by species and month. Species Alosa aestivalis (Blueback herring) l'i:j)seuaoharengus (Alewife) 1'i:. sai5Tcl1ss1'!la ,American shad) Anchoa m1tch1lli (Bay anchovy) J:irigurrla rostrata (A'!lerican eel) Brevoortia tvrannus (Atlantic menhaden) cvnoscion reqa lis (\\'eakf ish) Cyprinus carpio (Carp) Etheostom~tedi (Tessellated darter) Funauius diaohanus (Banded killifish) F. heterochi:us (Htmmichog) Hybogna thus regius (Eastern silvery minnow) Ictalurus catus ,i,\nite catfish) I. nebulosus ,Brown bullhead) T. punctatus (Channel catfish) Leicstomus xanthurus (Spot) Mer:ibras mart1n1ca ,Rough silverside) Men101a bervllrna (Tidewater silverside) H1cropogon1as undula.tus (Atlantic croaker) !'!crone americana \. i\ru te perch) Mororle saxatilis (Strioed bass) Hotropis huasoruus am3rus· ( Spotta il shiner) Faralicnthvs ae!ltatus \.bU'!l.'!ler flou!lder) t'erca rlavescens ,rello,v perch~ Pomoxis annuiaris (\\'hite crappie) F. niqromaculatus (Bl3ck crappie) ~trongy1ura marina (Atlantic-needlefish) 1-rinectBs macuiatus (Hogchoker) Callinectes saoidus (Blue crab) July 10,063 179 6 461 1 2 1 18 38 8 12 1 1 10,791 Pushnet August 5,948 205 3 11 631 1 4 63 12 8 1 4 6,891 3 September 7,067 229 258 107 1 9 50 4 3 7,728 5 Total 23,078 613 3 275 l, 199 1 3 1 1 31 151 24 23 1 1 1 4 25,410 8 July 64 39 12 3 17 1 80 55 11 70 650 11 698 1 162 4 3 653 2,534 437 4.9 m Semi-balloon Trawl ------- -------August 122 96 83 2 11 2 58 6 5 2 56 794 1 10 306 27 6 461 2,048 294 SepteT.ber 125 54 154 1 7 7 3 47 1 11 13 69 285 239 33 7 566 1,622 173 Total 311 189 249 6 35 9 4 185 1 72 29 2 195 1,729 1 21 1,243 1 222 17 3 1,680 6,204 904 I-' f\) Table 3. Monthly catch-per-unit-of-effort ( CPUE) of blueback herring, alewife, Ame.rican shad, 1vhite perch and striped b:.rns by stratum by pushnet (A), and 4.9 m s6i"ni-balloon trawl (B). Pusr1.11et CPUE expressed in catch per lOOO m3. Trawl CPUE expressed in catch per standard trawl. A. Pushnet River Nile 80-85 70-75 60-65 50-55 Grand CPUE B. 4.9 m Tra\·Jl River Hile 60-65 55-60 50-55 45-50 40-..';.5 35-40 Grand CPUE (a) not sampled Blueback herrL~g Ale-wife A11erican shad Jul Aug_ 597 .3 221.2 2214.5 348.3 830.0 1219.2 132.4 271.8 937.l 512 .3 White perch Jul Aug (a) (a) 57.6 23.0 14.2 9.6 54.0 15.3 4.6 6.0 o.s 28.l 10.1 Sep 4.3 9.0 4.0 4.7 1. 7 (a) n r ._,. .o Se])_ __ Jul --340.4 14.5 1416. 7 26.0 495.8 24.9 · 35 .o 1.5 578.l 16. 7 Striped bass Jul (a) 0.3 0.1 Aug~ (a) (a) Aug 17 .1 6.3 37.2 9.8 17.6 Sep 40.7 23.7 7.1 2.0 18.7 Jul Aug Sep 1.0 0.2 Blueback herring ~Aug~ Ale-wife Jul Aug (a) Sep 2.7 (a) 13 .3 (a) 16. 0 0.6 25.0 (a) 2.0 6.0 7.3 13.3 6.7 15.3 1.3 24.6 11 r '+. 0 0.3 0.5 7.6 (a) 7.7 9.0 3.3 14.6 2 ., . ..,. G.O 2.0 0.7 (a) 3.5 r-' vs \ I -~ ~ 17~ 'H.,.YFIELD · -To FREDERICKBURG 8 • ~ V ~~ ·;~,.eANNo''co -~( I ~~· .--·--\ L , , l ~o"'~ ~~~~ '~~~ ~ r, ~x· . . . \ ,, ..n\ l?4Pp4h'4NNO:;l( 11r/V£1? ~ 0/ /'---. M / -'-------: f~o i ·;,)~ , I ~ I ~ . Figure 1. Nursery area in the Rappahannock River sampled in July, August and September 1980 for juvenile striped bass, white perch, and alosine fishes. I-' ..r:,, 

Index of juvenile striped bass, white perch, and alosine fishes in the Rappahannock River following the March 1980 oil spill

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Index of juvenile striped bass, white perch, and alosine fishes in the Rappahannock River following the March 1980 oil spill

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