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A REPORT ON THE COOPERATIVE BLUE GRAB STUDY- SOUTH ATLANTIC STATES' Robert K. Mahood Georgia Game and Fish Commission Coastal Fisheries Division 2 Michael D. McKenzie Douglas P. Middaugh Bear Bluff Laboratories South Carol Wildlife Resources Department Sean J. Bollar Florida Department of Natural Resources Division of Marine Resources' John R. Davis Dennis Spitsbergen North Carolina Division of Commercial and Sport Fisheries' February 1970 This study was conducted in cooperation with the U.S. Department of Interior, Bureau of Commercial, Fisheries and financed under the Com- mercial Fisheries Research and Development Act, 88-309 Section 4 (Project; Numbers 2-79-R-1, 2-80-R-1, 2-281-R-I and 2-82-R-1) 2 Contribution Series Number 19 3 Contribution Serees Number 139 4 Special Scientific Report Number 18 QL 444 .D3 R46 1970 ABSTRACT The cooperative blue crab study was designed to determine the cause(s) of blue crab mortalities and to delineate significant factors affecting the relative abundance of marketable crabs. A multiphased approach provided background information rela- .tive to re.-ional hydrological cliaracteristics, diseases and parasites, arid residual pesti- cides associated with blue crab populations. Standardized routine monitoring at 20 South Atlantic sampling areas provided hydrological data that were illustrative of typical seasonal patterns. A total of 195 blue crab samples (1,95 0 individual crabs) was collected from es- tablished stations and processed for pesticide analyses. Chlorinated hydrocarbon pesticides were detected in all samples. Approximately 100 blue crabs were collected by each state from established sta- tions for histopathological data. The organism most emphasized during this study, Parantoeba perniciosa, was detected along with several other potential pathogens, but -at levels not sufficient to cause blue crab mortalities. Laboratory studies were conducted to determine the effects of selected hydrological factors and pesticides on blue crab mortalities under controlled conditions. Upper and lower thermal tolerance limits for adult crabs wei -e defined at various test salinities. Generally, test crabs were Jess tolerant at low salinities and high temperatures and at high salinities and low temperatures. Delineative screening of DDT and Toxap4eiie showed these compounds to be more toxic at lowered salinities (8.6%@) with toxicities increasing as temperatures ranged above and below 15' C at all test salinities. Toxicity was slightly greater at the lower thermal extremities. Mirex, t@e technical compound, was relatively non-toxic to adult and sub-adult crabs. However, TMirex in a granulated bait showed delayed toxicity when ingested by juvenile blue crabs (< 3 inch carapace width) in test concentrations of 0.036 grams/liter. Crab survival time and metabolic rates were correlated with environ- mental combinations. INTRODUCTION the Bureau of Commercial Fisheries. These sessions culminated in a cooperative re- Massive rnortalities and a decline in search prograry-I between the South Atlan- abundance of the blue crab (Callinectes tic states, with federal financing by the sapidus, Rathbun) occurred along the South U. S. Bureau of Commercial Fisheries as Atlantic coast from 1966 through 1968 authorized under Section 4-b (disaster (figure 1) - First mortalities were re- funds) of PL 88-309. ported in Jurie 1966 from Holden Beach, Standardized methods and procedures North Carolina to Ossabaw Sound, Georgia ere confirmed by committee members of and continued sporadically through the w summer. Further mortalities occurred in the participating states, and a standard June 1967 beginning in Georgia and spread format for recording all field and labora- up the coast as far as the Santee River in tory data was designed. Prior to initiation South Carolina during the summer. Mor- of the program each state individuDIly se- talities beginning in April of 1968 were lected five locations to monitor monthly. confined to the Georgia coast. These de- Since it is probable that a combination clines affected the economic stability of of factors contributed to the decline in blue the crab industry and commercial fisher- men witnessed a drop in production from crab populations, this study was under- the high of 40.2 million pounds in 1.964 to taken in four pliases: Hydrology, Occur- 24.4 million pounds in 1968. ence and Abundance of Pesticides, Blue Crab Diseases and Parasites, and Labora- A series of biological conferences were tory Studies of Factors Affecting Crab held between the four affected states and Mortalities. C7 US Department of Commerce NOAA Coastal Services Center Library 223,1 South Hobson Avenue C.D Cliar:Ceston, SC 29405-2413 (5) Twrbidity was measured with a Secchi disc. Ali data, except turbidity, were derived samples collected in a from bottom watei non-contarninating three-bottle train sainp- ler as described by Swingle and Johnson (1953). 51 Results and Discussion A summary of the hydrological charac teristics is presented in Tables I through "'4 @1@' 4. J' South Atlantic Coast Bottom, water temperature for the ten month study period ranged f rom 3.3 to 31.0' C (Table 1). Dissolved oxygen read- Figure I.-Scenes such as this were common ings ranged from 1.7 to 11.6 ppm (Table in some areas of South Carolina, North Caro- 2). Salinities ranged from 1.1 to 35.5'0,, lina, and Georgia during 1966, 1967, and 1968. with an over all average of 24.615@@ (Table 3). Turbidity readings varied from a low Study Areas of 10 cm to a high of 250 era (Table 4). PH readings for all study areas varied only A preliminary survey was made in each 1.5 pH units, from 7.0 to 8.5. state to locate five sampling stations . In cIhoosing the stations, it was necessary that they 1) were representatives of the various Vorth Carolina saltwater ecosystems found in each state, Temperatures appeared to follow usual 2) were located in a commercial crabbing winter to summer fluctuations with a low zone, and 3) were, if possible, 'In. an area 3.0" C registered at station 5 in March where previous crab mortality Oes) had oc- and a high of 31.0' C at station 5 in curred. The map on the back cover de-' August. picts the general location of the 20 gta- The highest dissolved oxygen Y-eadings tions. Throughout the text the study were recorded in March and the lowest in areas will -be referred to as station num- September at all five stations. bers corresponding to those on the map Salinity was recorded at sea water con- and in the appendix. centrations at stations 1 and 2. The low- Phase 1. HYDROLOGY est level recorded was at station S. PH changed little during the ten months Methods and Materials of testing, but did tend to be more basic The following parameters were moni- in the fall. Turbidity increased in the summer, de- tored monthly at each station: creasing as the water temperature cooled. (I)Bottom temperature was recorded with a rapidly equilibrating mercury im- mersion thermometer. South Carolina (2) Dissolved oxygen was ineasured Bottom water temperatures were dis- by the azide modification of the Winkler tribLited by seasonal ranges at each station. method (Standard Methods, APHA 1,9651). Minimum water temperatures ranged from (3) pH was determined with a La- 8.7o to 10.0' C, upper temperature levels Motte block comparator accurate to :t 0.25 varied from 29.0' to 31.0' C. PH units. Salinities varied by station over a wide (4) Salinity ,vas determined with a range. Lowest salinity readings (2.7 - temperature compensating American opti- 10-M) were preceded by heavy rainfalls cal refractometer calibrated in index of with absolute minimum values recorded on ref raction. ebb tides. These low salinities usually re- (2) x", covered. rapidly with tidal flushing. tion 1). The most stable turbidity read- Turbidity and dissolved oxygen follow- ings were recorded at station 3. ed a general seasonal pattern with low Florida readings during the warmer month and ebbing tides. The pH measurements were Bottom water temperatures ranged relatively constant at sea water levels of from a low of 13.5' C in December, at sta- 8 units. tion 5, to a high of 30.1' C in August at Georgia station 3. The greatest temperature de- cline occurred from October to November, Seasonal bottom temperatures ranged for all stations, and the greatest increase from 10' to 31' C. Variations between in April to May for stations 2, 3 and 5. high and low temperatures were similar at Stations 1 and 4 showed the greatest in- every station. The sharpest rise in tem- crease during May and June. The nar- perature (12.5' C) occurred between March rowest seasonal fluctuations occurred dur- and April at station 1. All other stations ing summer months, with station 2 show- also showed a marked rise in bottom water ing the most variation. temperature during this period. Temper- Lowest dissolved oxygen for all stations atures reachbed a peak in July at all sta- was 1.7 ppm taken at station 3 during tions. The highest recorded bottom tem- April. Station 3 also had the lowest over- perature (31' C) was at station 5. Tem- all seasonal average of 3.6 ppm, while sta- peratures droped as much as 9' C between tion 2 showed the highest average with 5.5 October and November. ppm. Highest dissolved oxygen was 7.2 Dissolved oxygen levels ranged from 3.0 ppm found at station 5 during June. to 9.4 ppm. Levels at station 2 stayed at Bottom salinities fluctuated consider- 3.0 - 3.2 ppm during June, July, and Au- ably at all stations. Station 1 had the low- gust. Dissolved oxygen levels at the other est salinity ranging from 1.1 to 26.9%. four stations were somewhat higher dur- Station 5 fluctuated least, ranging from ing this period ranging from 3.2 to 5.7 17.2 to 31.2%. Salinity patterns at stations ppm. The lower dissolved oxygen at sta- 2 and 4 (nearest the ocean) fluctuated from tion 2 did not appear to harm the local 13.5 to 34.5%, and 23.2 to 35.5%. Salin- crab population. ities were generally highest during the Salinities ranged from 15.15 (Novem- summer months, except for station I which ber, station* 5) to 32%. (July, station 4). peaked in May and declined rapidly during The greatest seasonal fluctuation (15.6%) August, reaching a low of 1.1% in Octo- occurred at station 4. ber and November. pH ranged from 7.3 to 8.2 with the The highest Secchi disc reading was 155 greatest variation of only 0.6 units occur- cm at station 1, July, but station averages ring at station 1. Highest pH readings (76 cm) were much lower. During Septem- were recorded at Station 4 which was lo- ber and October, stations 2 and 3 were less cated near a polluted area. than 50 cm, but both were sampled during Turbidity readings ranged from 177 cm. flood tide when there were strong turbid (March, station 1) to 22 cm (August, sta currents. TABLE L-Summary of observed bottom temperature data from each state, Temperature in *C N. Carolina S. Carolina Georgia Florida South Atlantic Sta. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. For All Stations 1 10.0 28.0 20.5 8.7 30.8 20.9 10.0. 20.0 21.3 15.5 30.0 24.9 2 9.4 29.0 20.9 10.0 29.0 22.1 10.0 29.5 22.1 16.G 29.9 24.3 3 7.8 28.6 20.2 10.0 31.0 22.0 10.0 29.5 21.6 15.5 31.0 24.8 3.3 31.0 22.2 4 6.7 27.8 20.1 8.7 30.3 21.6 10.0 29.5 22.4 15.0 30.0 24.6 5 3.3 31.0 19.8 10.0 29.6 21.6 12.0 31.0 23.3 13.5 30.0 24.3 (3) TABLE 2.-Summary of observed dissolved oxygen data from each state. Dissolved oxijgcn in ppm N. Carolina S. Carolina Georg.im Florida South Atlantic Sta. @Min. Max. Avg. Min. Max. Avg. Mtn. Max. Avg. Alin. Max. Avg. Alin. Max. Avg. For All Stations 1 4,1 1,1 1,1 1,1 1*11 1,1 4,5 1*2 1,1 1*1 7*1 1,1, 2 6.2 916 7.8 5.0 0.0 6.1 3.0 9.4 5.4 3.6 6.5 6.3 3 5.4 9.8 7.0 5@0 8.0 6.8 3.7 9.4 6.2 1.7 5.8 S.G 1.7 11.6 G.2 4 6.8 10.8 S.9 4.0 8.0 6.2 6.0 9.3 6.6 2.9 6.8 4.6 5 6.0 11.6 7.9 5.0 9.0 6.2 3.2 8.6 6.5 2.G 6.8 4.9 TABLE 3.-Summary of observed salinity data from each state. Salinities in ppt. N. Carolina S. Carolina Georgia Florida South Atlantic Sta. rMin. Max. Avg. Min. Max. Avg. Min. 'Alax. Avg. Min. Max. Avg. Min. Max. Avg. For All Stations 1 29,6 34.6 32.2 2.7 32.3 25.2 16.2 28.1 22.S 1.1 26.9 16.6 2 291.6 35.3 $2.9 10.7 22.0 16.2 18.9 27.S 23.8 13.5 24.5 27.7 a 11.9 31.8 20.6 23.0 32.3 29.0 16.2 27.5 21.9 16.2 32.3 26.3 1.1 35.6 24.6 4 11.9 28.0 22.6 17.0 32.0 25.6 10.7 32.3 24.9 23.2 35.5 28.6 6 19.9 31.2 25.2 14.0 26.9 21.0 15.1 29.1 23.0 17.2 31.2 26.8 TABLE 4.-SummarV of observed turbidity data from each state. Turbidities recorded in cm W. Carolina S. Carolina Georgia Florlda South Atlantic Sta. Win. Max. Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. For All Stations 1 55 156 94 10 56 28 22 177 86 66 166 98 2 56 89 76 10 146 42 25 122 61 43 120 78 a 46 185 66 16 96 41 as 112 70 43 106 68 10 260 70 4 52 120 92 16 147 49 22 147 72 60 ISO 91 5 56 260 IOA 16 120 Be 48 167 75 60 135 90 (4) Phase H.-OCCURENCE AND sile technique for nonanionic pesticides. ABUNDANCE OF PESTICIDES Samples were analyzed on an electron cap- ture gas chromatograph. All completed pesticide data were returned to the partici- Methods an(! Materials pating states. Ten blue crabs were collected monthly from each of the 20 sample stations for pesticide residue analyses. Standard otter OCCURMENCE OF CHLORINATED brawls were used for collections during HYDROCARBONS I IN BLUE CRABS most of the sampling period, crab pots be- ing utilized only in the colder months. A total ol 50 blue crab samples (500 Prealialyses preparation of the crab individual ci@,abs) was collected from es- Samples was accomplished by taking 30 :t 5 t'ablislied station,,,, by biologists from each granis of soft tissu-@- from the teii crabs state, and p) @.ocessed for pesticide analyses. comprising a composite sample. The-soft Chlorinated .1 hydrocarbon pesticides were tissue, consisting of pieces of gill, hepato- detect ed in'all samples. DDT and its meta- pancreas, heart, intestine, testes, ovarian bolites we're found in 1001/c of the samples. eggs, and seminal receptacles froin each The highest values for DDT, DDD, and crab, was placed together in a pint jar and DDE in the crab samples were .247 (South chilled. A desiccant mix, consisting of Carolina), .188 (North Carolina), and .231 107o QUSO (a microfine precipitated silica) ppm (Georgia). Mirex was found in 35% and 90% anhydrous sodium sulfate was of the samples at a maximurn level of .389 added to the sample. It was then put into ppm (Georgia). Dieldrin occurred in only a freezer for two hours after which it was 19%, Ou f ille samples with a maximum level ground with a blender into a free flowing of .072 ppm (Georgia) (Table 5). powder. Processed samples, placed in aluminum foil, were folded and shaped into Idonthly variations in the occurrence of tight rolls and stored in plastic bags with chlorinated pesticides are shown in figure their appropriate data sheets. This tech- 2. Peak levels of total DDT in crabs oc- nique, recommended by the Bureau of Com- curred during early spring and summer mercial Fisheries Biological Laboratory at while Dieldrin reached maximum levels Gulf Breeze, Florida, prevents spoilage Of during May and October. Mirex was found the sample and degradation of the pesticide at highest levels from April through July. residues for at least 30 days without re- frigeration. Although these data are not sufficient The South Carolina State Board of for predicting seasonal variations, some degree of interpretation ,vas attempted. Health Laboratory in Columbia, South Car- olina, was under contract to @nalyze the Monthly fluctuations of total DDT and Dieldrin probably indicate Seasonal differ- 195 samples for pesticide residues. ences in agricultural activities that were These monthly samples were analyzed magnified by maximum fresh water run- off during summer and fall. The pres- by gas chromatography for the following chlorinated hydrocarbons: Aldrin, BHC, ence of Mirex can be directly associated Dieldrin, DDT, DDE, DDD, Endrin, Hep- with fire ant control. tachlor Expoxide, Methoxychlor, Mirex, Toxaphene, and Chlordane. The only pesti- Since the parent compound DDT was cide residues found in recordable quanti- generally present in higher quantities than ties were DDT, DDD, DDE, Dieldrin, and its metabolites DDD and DDE, the crabs Mirex. Were probably exposed to pesticide run- off. There is also an indication of residue The procedure developed by Maunder buildup from transmission through the (1964) was used in extracting pesticide food web, since metabolites of DDT are residues from the crab samples. Cleanup present in all samples (Keil and Priester, was accomplished using the standard flori- 1969). North Carolina A summary of pesticide levels from the 50 crab samples collected in North Carolina are shown in Table 6. Of the 50 samples analyzed all were found to contain varying concentrations of DDE, DDD, and DDT. Only 10% of the total number showed any trace of Dieldrin and 16% contained Mirex. DDE, DDD, and DDT showed their high- est concentrations in the spring with DDE, reaching a level of .122 ppm and DDD and DDT reaching highs of .188 and .213 ppm. Dieldrin was detected in the March and December samples but in very low concen- trations, the highest being .005 ppm. Mirex was found in October, November, and December samples, the highest concen- tration being .045 ppm in December, South Carolina Chlorinated hydrocarbon pesticides were detected in all 50 of the blue crab samples collected, in South Carolina. Table 7 shows that DDD, DDE, and DDT were found in all 50 samples ranging from .009 to .160 ppm, .011 to .180 ppm, and .012 to .247 ppm. Mirex was found in 44% of the Figure 2-Average monthly occurence of DDT Samples at concentrations in the range of (total), Mirex, and Dieldrin in crab samples .005 to .209 ppm. Dieldrin was detected collected at 20 South Atlantic stations. in 28% of the samples at a range of .002 to .019 ppm. TABLE 5-Chlorinated Hydrocarbon Pesticide Residues in Blue Crab Samples from 20 South Atlantic Stations. No. of Samples Residue in Parts Per Million Pesticide Examined % Positive Mean Low High DDD 195 100 .073 .009 .188 DDE 195 100 .064 .010 .231 DDT 195 100 .086 .012 .247 Total DDT 195 100 .219 .034 .517 Mirex 195 35 .076 .005 .389 Dieldrin 195 20 .012 .002 .072 DDT and its Metabolites (DDD and DDE) TABLE 6-Chlorinated Hydrocarbon Pesticide Residues in Blue Crab Samples from North Carolina No. of Samples, Residue in Parts Per Million Pesticide Examined % Positive Mean Low High DDD 50 100 .051 .010 .188 DDE 50 100 .053 .013 .122 DDT 50 100 .077 .012 .21.3 Total DDT' 50 100 .181 .043 .491 Mirex 50 16 .023 .005 .045 Dieldrin 50 10 .003 .002 .005 1 DDT and its Metabolites (DDD and DDE) (6) Georgia DDT and its metabolites were present in all 50 of the samples collected in Georgia. These pesticides were found in varying amounts as follows: DDT,.018 to .176 ppm; DDE .015 to .231 ppm; and DDD, .012to .179 ppm (Table 8). These pesticides stayed at somewhat constant levels until the last three months of the study (October, November, and December) when concentrations declined sharply. Dieldrin, present in 36% of the samples, ranged from .004 to .072 ppm. Mirex was found in 54% of the samples, ranging from .015 to .389 ppm. Mirex was found in samples collected at station 3 more frequently than at any other station. Most Mirex residues were found in samples from July through December. Florida Thw highest DDt residues in crabs were found during the spring months, especially April which showed an average of .136 ppm. Summer DDT averages varied least with slightly lower amounts than spring (.075 to .077 ppm). During fall and winter months a declining trend for DDT was accompanied by the appearance and increase of Mirex. DDT reached its lowest level (.018 ppm) during December. Mirex frist appeared in September with an average level of .019 ppm, then increased to an average level of .061 ppm by December. Dieldrin appeared during October only, at a level of .008 ppm (Table 9). Table 7.--Chloringated Hydrocarbon Pesticide Residue in Blue Crab Samples from South Carolina Pesticide Examined %positive Mean Low High DDD 50 100 .076 .009 .160 DDE 50 100 .081 .011 .180 DDT 50 100 .92 .012 .247 Total DDT1 50 100 .249 .34 .517 Mirex 50 44 .88 .005 .209 Dieldrin 50 28 .009 .002 .019 1 DDT and its Metabolites (DDD and DDE) Table 8.--Chlorinated Hydrocarbon Pesticide Residues in Blue Crab Samples from Georgia Pesticide Examined %Positive Mean Low High DDD 50 100 .068 .012 .179 DDE 50 100 .077 .015 .231 DDT 50 100 .092 .018 .176 Total DDT1 50 100 .237 .053 .425 Mirex 50 54 .162 .015 .389 Dieldrin 50 36 .017 .004 .072 1 DDT and its Metabolites (DDD and DDE) Table 9.--Chlorinated Hydrocarbon Pesticide Residue in Blue Crab Samples from Florida Pesticide Examined %Postive Mean Low High DDD 45 100 .066 .012 .180 DDE 45 100 .047 .010 .114 DDT 45 100 .082 .018 .196 Total DDT 1 45 100 .195 .040 .468 Mirex 45 31 .031 .055 .164 Dieldrin 45 2 .008 .008 .008 1 DDT and its Metabolites (DDD and DDE) (7) Phase ill-BLUE CRAB DISEASES AND and sixteen in June. The Oxford Labora- tory will publish additional findings in PARA.SITES Ahe near future. Methods and Materials The occurence of Urosporidium crescens A disease and parasite sample of 30 Is directly associated with the trematode crabs was collected monthly at selected sta- metacerearia Microphallus which it para- tions in each state, along with data and sitizes. This hyperparasite may, actually samples for Phases I and 2. Crabs were help crabs by destroying trematode para- collected as described previously. sites which are common in the crab's muscle tissue and hepatopancreas. Live crabs were processed at the labor- atories within a few hours after collection. Each was examined externally and inter- nally for signs of diseases or parasites. Hemolymph smears frorn each crab -were obtained by cutting off the distal articula- tion of the fifth leg (dactylopodite or back fin) and allowing the hemolymph to drip f reely and clot on a glass slide. Small W pieces of the hepatopancreas, gill, gonad, k @,z4, muscle, heart, intestine, and eye stalks were taken from each crab. The tissue samples and hemolymph smears were each assigned .4, a code number and preserved in a 10%o neutral-buffered, formalsaline solution. Observations, remarks, and other per- 'g tinent information (crab' size, sex, and eedysis state) were recorded on data sheets. Lld After monthly samples were processed, they were forwarded to the U. S. Bureau of 'N@, Commercial Fisheries Biological Labora- tory at Oxford, Maryland, for diagnostic services. Results and Discussion Occurence of the "gray crab disease" (Sprague and Beckett, 1966) in wild pop- ulations of blue crabs was associated with massive crab mortalities in the South At- ]antic states during 1966, 1967, and 1968. This condition, caused by Paramoeba per- niciosa which infests itself in a crab's hem- olymph and body tissues (figure 3) wa!@, the main target for histological inves'tiga . . . . . . . tions during this study. As shown in Table 10 the frequency of crabs positive for diseases and parasites Figure 3--Blue crabs infected with Paramoeba was not significant. pernicosa often exhiblt a gray coloration on Parainoeba perniciosa was found in only their ventral side. This picture clearly shows the different coloration of an infected crab 18 crabs (1.5 percent of all crabs sampled). (top) and a normal crab (bottom). North Carolina accounted for 14 of the infected crabs while Georgia had three and Florida had one. Two were taken in May TABLE 10.-Summary of Diseases and Parasites found in 1,200 Blue Crabs Sampled from March through December 1969. By frequency of Positive Animals. Parasites Commensals Other' Month Paramoeba Metacerearia Urosporidium3 Microsporida Balanus OctolasMiS2 Mar. 1 - 9 5 2 Apr. - 5 5 3 5 May 2 - 6 5 5 June 16 1 9 - 2 July - - 8 12 - Aug. 6 6 3 5 1 1 &ept. a 3 - 7 4 0 et. 2 2 1 12 6 8 No-I. I 1 1 2 2 3 Dec. 1 1 - 10 2 2 I Necrotic lesions associated with Chitinoclastic Bacteria 2 Not recorded in North Carolina Samples 3 Hyperparasite that parasitizes the trematode metacercaria, without. the ,Urosporidium. present the metacerearia, are not readily detectable Im Lw Microsporidian infectiolis occurred in deeper high salinity -waters during the crabs from North Carolina and Florida. colder months. Those found in North Carolina were asso- ciated with a small localized crab mortality. Vhae IV-LAEORATOPY STUDIES OF A special mortality sample of ten crabs, FACTORS AFFECTING CRAB collected at Ocean Isle Beach near station 4, contained 5 crabs which appeared to have MORTALITIES' light to heavy microsporidian infections. Method's and Materials Since no other casual agents were discov- ered, these infections could have caused Since there was an absence of crab mor- this minor crab mortality. talities and the occurence of Paramoeba was so sparse, laboratory experiments were Current information concPrning the focused on the effects of certain. residual commensal Octolasmis (inulleri) lowei on pesticides on blue crabs. Pesticides were the gills of blue crabs suggests that it is a considered for -bioassay in accordance with potential pathogen. This organism occur- regional frequency distribution and in the red frequently but could not be related to final selection, D@T, IToxaphen-e, -nd Mirex crab mortalities. The organism Balanus were specified by the committee members eburneus, the common turtle barnacle, is as the problem compounds. not considered a potential pathogen. It was the most common organism found on Experimental crabs blue crabs during this study. Both Octo- lasmis and Balanits were often found in-. Bioassay specimens were collected from fecting the same crab, which was usually Wadmalaw Sound and stocked in reserve in its ultimate instar. holding tanks prior to acclimation in the laboratory. Crabs that had just moulted A total of 28 specimens exhibiting an or those designated as red-line peelers were unusual exoskeletal disease was 'collected. segregated from the test groups. Only adult crabs with a carapare width of 5 at various stations in North and South inches or more were used in the prelimi- Carolina. The nature of this disease was nary screening tests. Juvenile crabs less similar to that described by Rosen (1966). than 3 inches in carapace width were used Routine examinatlons of these crabs, which in certain delineative screening tests. All were held alive in fiber glass tanks at rel- atively constant temperatures ,(2 0' C 2 * crabs were fed cut bait during the hold- C) and salinities (26/1@), showed that the ing period prior to testing. infection manifests from a superficial ne- During 1. he collection periods, water tem- crosis. Eight of the specimens showed peratures ranged from 24' to 33' C. Crabs signs of the syndrome on their sterna with to be used in low temperature experiments numerous punctiform "corrosive" marks. were collected during the colder months and converselv those for high temperature Necro'tic lesions also occurred on the tests were taken during the summer. Sal- dorsal carapace of all specimens. One crab initities in the collection area ranged from had an advanced case which eventually re- 20 to 26 parts per thousand. sulted in death; this animal's distal see- tion of the lateral spine was detached to Bioassay tanks and controls such an. extent the gill filaments were vis- Eight wooden tanks (48x24xl2 inches) able. The causative agent involved was molded over with fiberglass were used as unknown, however, a review of the litera- immersion baths. Each tank was equipped ture (Hess, 1937) implies that chitinoc- with coils of copper tubing (% inch o. d.) lastic bacteria are one possible agent. for heat exchange and a corner airlift sys- Zobell (1946) relates this bacteria as a tem to facilitate even temperature circula- common commensal on marine crustaceans. According to Rosen (1966) this disease or a similar syndrome was found more fre- quently in crabs living under crowded con- 1 This phase of tha study was conducted at ditions for long periods. The specimens Bears Bluff Laboratories, Wadinalaw Island, caught in South Carolina were all taken in South Carolina. (10) tion. Custom made glass aquaria (16xl2x9 solved oxygen in each test. inches) were used as the test tanks for Water temperatures were maintained holding crabs. A total of three aquaria. relatively constant (+ 1' C) throughout each containing 20 liters of sea water was immersed in each of the bath tanks. The the experiments. A Blue M portable cool- 24 temperature controlled units were used ing unit I was used to cool water in a 200 simultaneously for delineative screening gallon reserve tank. The water 'was then tests. The preliminary screening was con- pumped continuously through the heat ex- hangers and returned to the reservoir for ducted in a constant temperature room (ambient temp. 20' + 3' C) with an addi- re-cooling. To prevent excessive evapora- tion and a loss of exchange efficiency, each tional 24 bioassay tanks. immersion tank was covered with a sheet An industrial air compressor designed of 1-inch styrofoam insulation. A schematic for continuous duty at an operating range diagram of the bioassay laboratory is of 25 to 50 psi was utilized as a central unit shown in figure 4. for supplying oxygen to each bioassay tank. The aquaria were fitted individually with 1 Mention of tradename does not imply en- an adJustable air valve for controiling dis- dorsement. air compressor air-conditioner wash oreo storage storage water bath aquaria reserve fork Circu pump Figure 4-Lay-out of bioassay laboratory (11) For experiments requiring above ambi- The delineative pesticide screening data ent wrter temperatures, a Blue M immer- were statistically analyzed according to the sion heater was used in the reser voir with methods of Litchfield and Wilcoxon (1949) heated water being pumped through 'the to determine TLm values, variations, slope exchange system.- Although the heater functions, and 950/0 confidence intervals. maintained reservoir temperatures to with- in -L 2.5' C, there was a loss of heat effi- ciency during circulation. To compensate Lethal Levels of Temperature and Salinity for this loss, a thermostatically controlled rex glass immersion heater was used in. Sixty-six combinations of temperature each aquarlia for finer accuracy. py and salinity were tested to determine the effects of abrupt changes of these environ- Reduced salinities were obtained by miy- mental factors on blue crabs. Dissolved ing sea water with tap water in desired oxygen concentrations were recorded as a proportions. Increased salinities were ob- function of the two variables (Green and tained with Rila sea salts. Carritt, 1967). Table 11 giv@s a summary of 'the results. Bioassay Standards Cold induced blue crab mortalities oc- Static bioassays were conducted over 96- curred. at all combinations of salinity at 0' hour exposure periods as described in C. At 5' C crab survival was higher at the Standard Methods, APHA (1965). Blue lower salinity range of 8.6 to 13.4%,. As Crabs exposed to extremes of temperature temperatures increased to the upper ex- and salinity were considered dead when no tremes (30o to 36' C) crab survival be- n moverne, t could be detected upon close ob- came higher at the maximum salinities. servation. When exposed to lethal or near Generally, crabs were less tolerant at low lethal concentrations of pesticides, test salinities and high temperatures and at crabs would remain in a moribund condi- high salinities and low temperatures. The tion for hours without recovery or reac- TLm values were estimated from the ex- tion to mechanical stimulation. Therefore, perimental data by straight-line graphical a crab's death point was assumed upon its interpolation (Litchfield and Wilcoxon los of equilibrium or "overturning" in the 1949). Upper and lower tolerances a; pesticide solutions. All results were ex- various salinities are listed in Table 12. pressed as median tolerance limits (TLm) which is that concentration causing a 505o By plotting these data graphically on mortality or loss of equilibrium within 96 thmi- temperature and salinity coordinates as in hours. Five concentrations in logari figure 5, an almost linear relationship il- cally increasing quantities (plus a control lustrating the zone of thermal tolerance is without pesticide additive) were tested in established for upper and lower values. each set of bioassays. Six crabs were @Iaced in each concentration and control. Prior to each test, experimental crabs were acclimated for 24 hours at constant tem- peratures and salinities which were grad- ually increased or decreased by 2 unit in- tervals per day until the desired testing conditions were established. Since the pesticides were relatively in- soluble in sea water, acetone was used as a solvent in preparing stock solutions of each compound. Stock solutions. were titrated Into the test medium to obtain desired con- centrations. Acetone in volumes equiva- lent to the largest in a dosage series for any pesticide was always used in control tanks. (12) .7, TABLE 11-Reactions of adult Blue Crabs to Temperature and Salinity combinations with recorded dissolved oxygen. Expressed as Percent Survival over 96 hours Test Salinities 8.6 13.4 19.3 24.2 30.1 36.0 oc D. 0. D. 0. D. 0. D. 0. % D. 0. % D. 0. % Temp. nil /1 Sur. MI /I Sur. MI/I Sur, MI/1 Sur. Ml /I Sur. MI /I Sur. 0 9.6 0 9.4 0 9.0 0 8.7 0 8.4 0 8.0 @O 5 8.6 80 8.3 60 7.9 40 7.6 20 7.3 0 7.1 0 10 7.5 100 7.3 100 7.0 100 6.8 100 6.5 40 6.3 20 15 6.7 100 6.5 100 6.3 100 6.1 100 5.9 100 5.7 40 18 6.3 100 6A 100 5,9, 100 5.7 100 5.5 100 5.3 40 21 5.9 80 5.7 80, 5.6 100 5.4 100 5. 2 100 5.0 so 24 5.6 20 5.4 80 5.2 100 5.1 100 5.0 100 4.8 100 27 5.3 0 5.1 40 4.9 1100 4.8 Too 4.7 100 4.5 100 30 5.0 0 4.8 40 -4.7 80 4.6 100 4.4 100 4.3 80 33 4.7 0 4.6 0 4.4 0 4.3 100 4.2 100 4.0 100 4.3 36 4.5 0 4.4 0 0 4.1 0 4.0 40 3.9 so TABLE 12-Estimated 96-hour TLm for adult BlueCrabs at various salinities TLm Values C Sal. Acclimation temp C + 2 Upper Lower 8.6 20 22.0 3.2 13.4 20 26.1 3.8 19.3 20 30.6 5.6 24.2 20 34.2 6.5 30.1 20 35.2 10.7 36.0 20 35.2 18.5 40 salinity. Tagatz (1969) diagramed upper and lower thermal 48-hour TLm. values 35 against acclimation temperatures. His re- sults showed that at both high and low 30 salinities the upper and lower TLm values 25 increased with increases in acclimation temperatures. His data generally agree with results of this study. Acclimation time and temperature was an obvious fac- 20 Tolerance Zone tor in the final results of the two studies. 15 The percentage of adult crab survival ap- 10 parently becomes greater as the difference between acclimation and test temperature 5 decreases. There appears to be an important phy- 0 siological-ecological relationship among the 9.6 13.4 19.3 24.2 30.1 36.0 tolerance limits at various temperatures salinity and salinities. The metabolic rate of crus- Figure 5-Upper and lower thermal tolerances taceans is generally temperature oriented for adult blue crabs exposed to abrupt changes with higher rates of metabolism corres- in temperature and salinity. ponding with temperature increases (Wa- terman, 1960). King (1964) also showed On the lower end of the correlation, the that lower salinities had a marked increase minimum thermal tolerance limits decrease on blue crab metabolism. This indicates as salinities increase. The upper tolerance that at low salinities and high tempera- limits show a reverse pattern with maxi- tures the strain of osmoregulation would muni tolerance at 35.2 C and a downward add to the stress of metabolism and thus trend corresponding with decreasing salin- decrease the upper TLm. values at such ities. By connecting the upper and lower combinations. In a reverse situation, low thermal tolerance limits, the range of all temperatures may reduce metabolic activity tolerable temperatures is shown at each to such a degree that it would be difficult for crabs in high ties to maintain external movement and sound. Reactions favorable gradient between external and began with increased activity and erratic internal salinites. Ree, (1966) stated swimming, and ended with convulsions and that blue crabs in full strength sea water a loss of equilibrium. (35 ) maintained a blood concentration slightly below that of the water regard- less of temperatures between 10 and 30 Delineative Screening C. However, Tand and Van Engel (1966) showed that blood osmoconcentrations of Results from testing combinations of adult blue crabs were hypertonic to 10 , temperature and salinity against varying 30 , and 3 slainites at 20 C. Rees pesticide concentrations are recorded as (1966) further emphasized that in most 96-hour TLm values in Table 13. DDT cases higher blood concentrations were was more toxic thant Toxaphene or techni- maintained with temperature decreases. cal Mirex at all combinations. A compara- This would indicate that blue crabs can tive relationship is illustrated in figure 6. successfully regulate their internal envir- onments near the lower end of their ther- mal tolerances. Rees (1966) also stated that adult female blue crabs showed less regulatory abilities than adult males in the lower salinities. This differential ability to regulate sodium in the blood may well explain why sexually mature females pre- fer higher salinity waters, especially dur- ing fall and winter months. Effects of Chlorinated Pesticides on Blue Crabs Preliminary Screening Initial tests with DDT and Toxaphene indicated a rather high level of toxicity to adult blue crabs; technical mirex in solu- tion was relatively non-toxic to adult and sub-adult crabs. However, if ingested, Mirex, in the form of granulated bait was toxic to juvenile crabs. All test crabs died after 24 hours of con- tinuous exposure to 1.0 ppm DDT. Toxa- Figure 6--Comparative 96-hour TLm values of phene killed 100% of the test crabs after DDT, Toxaphene, and Mirex at various com- 72 hours exposure at 10 ppm Technical binations of temperatures and salinity. Mirex in suspension had measurable ef- fects only at the end of 72 hours exposure in concentrations exceeding 500 ppm. Mi- rex granulated bait (85% corncrib grit, 15% soybean oil, and 0.3% Mirex) ingested by juvenile crabs showed delayed toxicity when present at equivalent rates of 2.35 pounds per acre. Test crabs responded to the more toxic polychlors within a few hours after ex- posure, displaying extreme sensitivity to (15) Table 13-Toxicity of pesticides on adult blue crabs at various temperatures and salinities (96-hour TL-a) TLm (PPM) with 95 percent Confidence Interval and Slope Functions Sal. Temp. DDT Toxaphene Mirex C Mm SP TLm SF TLm SF 10 .019 1.5 .580 2.1 159 3.0 (.009-036) (.460-.920) 83-302) 8.6 15 2.5 .900 3.0 180 (.030-.084) (.470-1.70) (128-250) 21 .035 1.9 .3370 3.2 72 2.1 (.021-057) (.180-.700) 48-108) rq 10 .043 3.1 .960 2.7 260 2.0 (.025-.078) (.590-1.50) (173-390) MS. 15 .213 1.7 3.80 1.8 220 2.6 (.160-.280) (.270-5.20) (137-352) 21 .045 1.8 .770 1.7 56 1.7 (.030-.067) (.570-1.00) 40- 78) 10 .080 1.5 1.20 1.8 265 1.8 (.070-110) (.910-1.50) (188-371) 24.2 15 .120 1.3 2.70 3.4 220 2.0 (.100,140) 1.3- 5.9) (152-275) 21 .114 2.6 1.00 3.2 105 1.3 (.073-.190) (.570-1.75) 75-147) All three compounds were more toxic There were delayed toxic effects at all with decr,@asjng salinity. At cach salinity, combination,, except 10' C. An increase however, "he defined. tolerance limits were in dosage from .036 g/liter to I g/liter higher at 15' C. Above and below this did not substantially alter the survival mid-point, the TLrn values decreased -%vitli times. Follow-tip experinients with high toxicity being more pronounced at the conceutrations indicated a threshold reac- lower extreme for DDT and Toxaphene. tion time; a stage was reached when fur- Mirex was more toxic at higher tempera- ther increases in concentration did not tures -%vithin each salinity bi-acket. This shorten survival thne. Extensive observa,- compound, however, cannot be classified tion showed the juvenile test crabs ingest- with DDT and Toxaphene since its order ing particles of the bait. These crabs were of toxicity as a contact poison is compara- transferred to non-contaminated aquaria tively low. and rnon;tored. After 96 hours in pesti- cide free water, the crabs showed acute Lethal levels of DDT were established irritation which resulted in spasmotic within relatively narrow confidence inter- muscle contractions, a loss 'of equilibrium vals, indicating consistent toxic effects with and finally death at the end of 192 hours. little range between concentrations caus- These data suggest that Mirex bait acts as ing survival and death. The calculated a stornach poison and, if ingested by ju- slope functions were low (rariging from venile crabs, is a definite mortality factor. 1.3 to 3.1) and the regression was steep, indicating that toxicity was accurately de- Figure 7 illustrates the relationship be- fined at low levels. In sharp contrast, tween temperature and relative toxicity of Marking (1966) found the slope function the bait. p. p.' - DDT for goldfish to be 6.02. This was indicative of a flat curve with -wl Equivalent in gram wt./water surface confidence intervals and, consequently the area to 1.25 lbs./acre as calculated from toxicity was difficult to define accurately. aquaria measuring 16.7 inches. The confidence limits for the TLin values of Toxaphene were somewhat wider than those of DDT and the calculated slope functions larger. This indicates that in- creased concentrations in the survival and mortality range produced less effect with- in the 96-hour bicassay. WO The toxicity of Mirex in acetone solu- so tion was difficult to define accurately as evidenced by the high TLm values and wide confidence intervals. This com- 70 .-20@ pound remained in solution only a short time before precipitating out. Mirex gran- ulated bait-4X was bioassayed with adult, 50 sub-adult, and juvenile crabs. Adult (5 40 inches or more), arid sub-adult (S to 5 3* inches) crabs were not outwardly affected by the bait material even in equivalent 20 doses of 10 times the standard application rate of 1.25 pounds per acre. However, 10 juvenile crabs (< 3 inches) exhibited ex- 0 treme sensitivity to the bait. At concen- - trations of .036 grams per 2.8 square feet 6 i4 4 i2 iG LiO li4 1" 192 of surface water area', juvenile crabs Sunild time - Noun showed variable signs of delayed toxicity at temperature - salinity combinations. Figure 7-Survival curves for juvenile crab3 Table 14 presents a summary of replicate exposed to equivalents of 1.25 lbs./acre Mirex tests conducted with the bait. bait at salinity of 22%o. TABLE 14.-Average survival data from replicate tests on juvenile blue crabs exposed to Mirex Granulated Bait - 4X1. .(The numbers under each concentration indicate percent survival after the given exposure time) Bait Concentrations .036 g2 0.5 g3 1.0 g4 22% 30% 10% 22% 22% Exposure Time Hours 10 C 20 C 27 C 15 C 20 C 20 C 20 C 0 100 100 100 100 100 100 100 24 100 100 100 100 100 100 100 48 100 100 80 100 75 100 94 72 100 81 50 100 3 75 54 96 100 63 20 100 38 50 69 120 100 25 10 75 38 31 44 144 100 13 0 50 38 19 25 168 100 13 0 50 25 6 3 192 100 0 0 44 0 0 1 Controls averaged 90% survival or better in all tests. 2 Gram equivalent to standard application rate. 3 Gram equivalent to 13.8 times standard application rate. 4 Gram equivalent to 27.7 times standard application rate. As depicted, the toxicity rate appears Related Discussion to be temperature dependent. At 10C The toxic effects of DDT and Toxaphene there was no mortality recorded but as on blue crabs, have been thoroughly docu- temperatures increased from 20 to 27 C mented. Butler (1963) presented data on the survival times and rates decreased. the effective concentration (EC.) of both This would indicate that toxicity might be these compounds on juvenile blue crabs. defined as a function of metabolism. A The 48-hour EC. for DDT and Toxaphene partial relationship between salinity and was .01 and .33 ppm, respectively. Com- toxicity of the bait material is evident. paring these results with those obtained However, temperatures appeared to be the from this study, the adult crabs tested un- major factor of influence. Further ex- der similar conditions (24%, and 21 C) are perimentation showed that small crabs approximately 10 times more tolerant to which had ingested Mirex bait at 27 C DDT and 3.4 times more resistant to Tox- could survive for an extended time at 1OC aphene. This study gave evidence that de- However, as temperatures were gradually creased temperature was a definite factor increased there were concurrent mortali- affecting the toxicity of DDT and Toxa- ties. Interpretation of these data indicates phene. Bridges et a]. (1963) also found that juvenile crabs ingesting the bait dur- that toxicity of DDT increased with tem- ing winter months could. possibly survive perature decrease. throughout the colder months, but as sea- sonal temperatures increased mortality Butler (1963) listed Mirex in solution would occur. as a relatively non-toxic pesticide to juve- nile crabs. The 48-hour EC was a high These data are purely suggestive but as 2 ppm. Later studies by McKenzie from preliminary evaluations, it would ap- (1969) and Lowe (1969) suggested that pear that acute toxicity of the Mirex bait the bait formulation was a stomach poison depends on (1) availability of the bait to rather than a contact poison to juvenile hungry crabs, (2) size and age of the ex- blue crabs. The toxic effects, however, posed crabs, and (3) the season of ex- were delayed but once the bait material posure. was ingested moribundity was evident af- (18) ter several days. Field studies conducted South Atlantic coast. During this period at Bears Bluff Laboratories indicated that no major mortalities occurred at these sta- standard applications of Mlirex directly to ions thus preventing a correlation of data the estuary had no observable effects on -and crab mortalities. adult and juvenile crabs which -%vere caged A total, of 195 hydrological samples was within the test zone. Further studies iiidi- Liken at the 20 stations. Results of the cated that adult crabs could accumulate e x- routine monitoring phase for hydrology are treniely high residual levels of Mirex useful in illustrating seasonal changes in (8,860 ppm) in the stomach and still main- the blue crab study areas. In general, sea- tain an apparent resistance to the com- sonal variations were ty'pical ,vben com- pound. pared with available hydrological data. Miscellanewts Studies A total of 1,950 blue crabs was processed aild analyzed foi- pesticide residue levels. Diseased Crabs All samples contained DDT and its meta- North Carolina reported 14 blue crabs bolites, 35%o contained Mirex diid 201,/0 Diel- positive for Parainoeba from Brunswick drin. From these data it can be assumed County near the South Carolina line. Im- that most, if not all, blue crabs along the mediately, biologists obtained live speci- South Atlantic coast contain varying mens from the area for bioassay. The test amounts of DDT, DPE, and DDD. crabs were delivered to Bears Bluff Labor- Pesticide concentrations lethal to blue atories and stocked in fib(,rglass tanks with crabs in the natural environment are dif@ water temperatures and @@alinities adjusted ficult to establish. Because of the tend- to equal those of the sampling area. Con- ency of organisms to concentrate these hy trol crabs were collected from Wadmala-,v drocarbons through the food chain to levels Sound and stocked in a comparable eiivir- well above that of the surrounding medium, onment. Hernolymph was withdrawn from a relatively low initial concentration may the North Carolina crabs and injected into ultimately cause mortalities. In addition, the hinge of the dactylus of 10 control crabs there is undoubtedly a synergistic affect and into the cardiac sinus of 5 controls. of pesticide levels and other environmental All except one of the injected crabs sur- vived without any gross morphological or abnormalities such as industrial pollution. (LoNve, 1965). physiological changes. Test crabs showed no signs of the "gray crab syndrome" and Pesticide data collected during this study temperature-salinity variations fa iled to indicates a definite contamination of es- show correlation between mortalities and tuarine waters, representing a potentially diseases. Later analyses of hernolymph dangerous situation, which should be kept smears were negative for Farainoeba. under surveillance. In future pesticide sampling it is su.-gested that more infor- Summary and Conclusions mation be obtained by analysis of water and bottom samples in addition to tissue samples. The cooperative Blue Crab Project was initiated as a result of massive blue crab Blue crabs collected and processed for mortalities, which occurred in 1966, 1967, diseases and parasites totaled 1,170.. Al- and 1968, along with a general decline in though apparently prevalent in two prior crab production on the South Atlantic coast. years, there were no major outbreaks of This study was a cooperative effort be- "gray crab sickness" during this study. tween the states of North and South Car- Several. potential pathogens were present olina, Georgia, and Florida. but not abundant. The main purpose of the study was to Data collected tinder the disease and par- investigate environmental and pathologi- asite phase of the study will. contribute cal factors possibly associated -%vith blue to the overall body of knowledge being com- crab mortalities. Water chemistry, pesti- piled by the Bureau of Commercial Fish- cides, diseases, and parasites were moni- eries Laboratory at Oxford, Maryland. tored monthly, from March 1 to December This data is expected to be of value in the 31, 1969, at selected stations along the event of future mass mortalities. t Laboratory tests showed crabs to be less Green, E. J., and D. E. Carritt. 1967. tolerant to pesticides at low solinities and Neiv tables for oxygen saturation of high temperatures and at high saiinities sea water. Jour. Mar. Res. 25(2): and low temperatures. Chlorinated hydro- 140-147. carbon pesticides were most toxic at low salinity levels. Mirex, the technical com- Hess, E. 1937, A shell disease in lobster pound, was relatively non-toxic to adult (Homarus ainericamts) caused by ebi- and sub-adult crabs. However, Mirex in tino.vorous bacteria. J. Biol. Board a -anulated bait was toxic to juvenile blue Canada, 3: 358-362. gi crabs if ingested. Keil, J. E., and L. E. Priester. 10,6q, DDT uptake and metabolism by a marine ACKINOWLEDGEMENTS diatom. Bull. Envir. Contan. & Tox. 4 (3) : 169-173. The authors are deeply indebted to the King, E. N. 1965. The oxygen consump- late Dr. G. Robert Lunz, former Director tion of intact crabs and excised gills of Bears Bluff Laboratories, for his re- as a function of decreased salinity. .sourceful efforts in the organization of Comp. Biochem. Physiol, IS: 93-1.02. this cooperative research program. His en- couraging and invaluable counsel was sin- Litchfield, J. T., and F. Wilcoxon. 1949. cerely appreciated by all concerned. A simplified method of evaluating The authors acknowledge Mr. Charles M. dose-effect experiments. Jour. of Pharmacology and Exp. Therapeutics Frisbie, Mr. Robert Ingle, Mr. Edwin Joyce, Mr. Ed McCoy, and Dr. Thomas Linton, 96 (2) : 99-113. who in their respective states, directed and Lowe, Jack 1. 1965. Chronic exposure of, assisted in the implementation of this pro- blue crabs, Callinectes sapidus, to sub- ject. Thanks are given to Dr. Thomas lethal concentrations of DDT. Ecol- Duke and Mr. Jack I. Lowe who kiDdly re- ogy. 46(6): 900. viewed the manuscript. ...... 1969. Exposure of juve- o acknowledge the follow- '@s to Mirex. Unpublished data The authors als nile era ing individuals whose assistance in the ]a.- from U. S. Bur. Comm. Fish. Biol. boratory and in the field was greatly ap- Field Sta. Gulf Breeze, Fla. preciated: William S. Davis, Alston C. Badger, Seth Cutter, Thomas Wittkamp, Marking, L. L. 1966. Investigations in Evaluat' Richard Saunders, Charles Futch, Steven fish control. 10. ion of McMahon, Robert Presley, Carlton Rowell, P, P' DDT as a reference toxicant ip Steven Cobb, and Joe Quick. Special bioassays. U. S. Bur. Sport Fish. and thankso are given to Mrs. Mabel io Knight Wildl. Res. pub. 14: 3-10. who typed the manuscript. Maunder, Defaubert. 1964. Analyst 89: 168. LITERATURE CITED McKenzie, M. D. 1969. Preliminary ob- American Public Health Association. 1 -965. servations on blue crabs exposed to Standard methods for the examination Mirex. Unpublished data from Bears .of water and wastewater including Bluff Lab. Wadmalaw Is., S. C. bottom sediments and sludges. 12th Rees, G. 11. 1.966. Informal progress re- ed. New York, N. Y.: 545-63. port for July - Dec. U. S. Bur. Comm. Bridges, W. R., B. J. Kallman and A. K. Fish. Biol. Lab., Beaufort, N. C.: 1-3. Andrews. 1963. Persistance of DDT Rosen, B. 1966. Shell Disease of the blue and Its metabolites in a farm pond. crab, Callinectes sapidus. J. Invert. Trans. Arner. Fish. Soc. 92: 421-427. Path. 9(3): 348-350'. Butler, P. A. 1963. Commercial fisheries Sprague, V., and R. L. Beckett. 1966. A investigation. Pesticide Wildlife disease of blue crabs (Callinectes sap- Studies, U. S. Fish and Wildlife Ser. idus) in Maryland and Virginia. J. Cir. 167: 11-25, (20) Invert. Path. 8(2): 287-289. Swingle, 11. S., and M. C. Johnson. 1953. W"ateri-nan, T. R 1.60. The physiology Water sampler and water analysis kit. of Crustacea. Vol. I - Metabolism 12pressive Fish Cult., 15) (1) : 27-30. and growth. Academic Press, New York and London. 639 pp. Tagatz, M. E. 1969. Some relations of temperature acclimation and salinity Zobell, C. E. 1946. Marine microbiology - to thermal tolerance of the blue crab A monograph on hydrobacteriology, Callinectes sapidus. Trans. Amer. Cbronica Botanica, Waltham, Mass., Fish. Soc. 98(4): 713-716. pp. 43-145. Tan, E. C., and W. A. Van Engel. 1966. Osmoregulation in the adult blue crab, Callivectes sapidus Rathbun. Chesap. Sci. 7(1): 30-35. APPENDIX (22) Appendix Table A-Hydrological data coilected at the five No?-th Cag-olina saviplhiq stations. Bottom DO Salinity Turbidity Month Temp. ('C) (PPIII-) PH (CIII.) Station 1 Mar. 10.0 8.6 31.00 7.4 77 Apr. 21.1 7.7 32.90 7.4 61 May 20.0 5.8 32.855 7.5 64 June 26.4 8.4 34.47 7.5 76 July 28.0 7.3 33.93 7.5 80 Aug. 27.2 7.2 29.62 7.8 75 Sep. 25.0 4.1 29.62 7.8 55 Oct. 233 6.5 33.93 8.3 95 Nov. 14.4 7.7 1.10.69 8.3 100 Dec. 10.0 8.2 32.85 -8.1 155 Station 2 Mar. 9.4 9.6 35.30 7.4 70 Apr. 21.1 8.01 33.40 7.2 79 May 20.0 7.3 33.39 7.5 80 June 26.4 8.3 31.23 7.8 89 July 28.0 8.3 29.62 7.5 85 Aug. 27.8 8.6 32.85 7.8 68 Sep. 26.7 5.2 31.77 7.8 77 Oct. 22.8 6.4 34.47 7.8 55 Nov. 16.7 7.7 32.85 8.2 65 Dee. 9.4 7.9 33.93 8.0 85 Station 3 Ma'r.' 7.8 9.9 12.00 7.6 46 Apr. 18.9 7.4 21.50 7.0 67 May 20.0 8.5 31.77 7.8 54 June 26.5 6.0 11.85 7.5 68 July 28.5 7.2 12.38 7.5 70 Aug. 27.8 0 15.62 7.4 66 Sep. 25.6 5.4 29.54 7.9 58 Oct. 21.7 5.6 26.38 7.8 47, Nov. 15.6 6.8 21.00 7.8 63 Dec, 9.4 76.4 25.31 135 Station 4 Mar. 6.7 10.8 22.00 7.5 107 Apr. 18.3 9.5 24.60 7.3 113 May. 20.6 9.4 25.31 7.5 105 June 27.0 9.2 24.60 7.6 86 July 27.5 9.2 23.69 7.5 85 Aug. 27.8 8.8 11-85 7.5 52 Sep. 27.8 6.8 21.00 8.2 62 Oct.. 22.2 7.7 24.23 8.2 85 Nov. 14.4 8.5 26.50 7.2 104 Dec. 8.3 8.9 19.92 8.3 120 Station 5 Mar. 3.3 11-6 22.00 7.5 70 Apr. 19.3 8.9 26.50 7.2 104 May 22.2 6.2 31.23 7.8 73 June 26.4 26.92 7.5 85 July 28.0 7.2 25.31 7.7 80 Aug. 31.1 7.8 28.54 7.8 56 Sep. 26.7' 6.0 25.31 8.2 86 Oct. 19.4 7.6 21.00 8.2 67 Nov. 13.3 8.4 18.85 7.8 166 Dec. 8.9 9.5 25.85 7.9 250 (213) Appendix Table B Hydrologierd data collected at the five South Carolina sampling stations Bottom DO Salinity Turbidity Month Temp. (*C) (PP--) PH (cm.) Station I Mar. 8.7 8.0 31.8 8.5 32 Apr. 19.5 3.0 31.9 8.5 56 May 24.1 8.0 28.0 8.0 10 June 26.8 6.0 28.0 8.0 16 July 30.8 6.0 32.3 8.0 25 Aug. 26.5 8.0 2.7 7.5 24 Sep. 25.0 5.0 24.0 7.5 25 Oct. 24.0 6.5 25.0 8.0 28 Nov. 13.0 6.0 22.6 8.0 27 D@,-c. 11.0 7.0 27.0 8.0 38 Station 2 Mar. 10.0 9.0 13.0 8.5 145 Apr. 19.0 7.0 20.2 8.5 83 May 26.0 6.0 12.3 8.0 40 June 28.0 7.0 16.0 8.0 25 July 29.0 7.0 14.0 8.0 20 Aug. 28.0 7.5 10.7 8.0 25 Sep. 27.5 3.0 22.0 8.0 35 Oct. 24.0 5.0 18.0 8.0 10 Nov. 18.0 6.0 18.3 8.0 20 Dec. 12.0 5.0 18.0 8.0 20 Station 3 Mar. 12.0 8.0 30.8 8.5 85 Apr. 19.1 8.0 30.0 8.5 85 May 24.0 7.0 32.3 8.0 45 June 26.0 5.0 25.0 8.0 15 July 31.0 6.0 30.0 8.0 35 Aug. 27.0 7.0 31.0 8.0 30 Sep. 27.5 7.0 32.0 8.0 30 Oct. 26.0 7.0 32.0 8.0 30 Nov. 18.0 6.0 24.0 8.0 20 Dec. 10.0 7.0 23.0 8.0 33 Station 4 Mar. 8.7 8.0 29.0 8.5 147 Apr. 18.2 7.2 28.7 8.5 85 May 24.0 8.0 29.0 8.0 35 June 27.5 6.0 29.0 8.0 30 July 30.3 5.0 32.0 8.0 25 Aug. 29.0 6.0 27.4 8.0 20 Sep. 27.0 4.0 17.0 8.0 66 Oct. 24.0 6.0 18.0 8.0 16 Nov. 15.0 5.0 29.0 8.0 85 Dec. 12.0 7.0 17.0 7.6 30 Station 5 Mar. 13.5 9.0 23.9 8.5 120 Apr. 23.0 7.0 84.2 8.5 60 May 26.0 5.0 23.1 8.0 25 June 29.5 6.0 25.8 8.0 35 July 29.0 6.0 26.9 8.0 20 Aug. 27.0 6.0 19.0 7.0 16 Sep. 27.0 6.0 19.0 8.0 16 Oct. 19.0 6.0 15.0 8.0 16 Nov. 12.0 7.0 14.0 8.0 25 Dec. 10.0 5.0 20.0 8.0 25 (24) Appendix Table C-Hydrological' data collected'at the ffve Georgia Sampling statio'ns Bottom DO Salinity Turbidity pH (cm.) Month Temp. ('C) (ppm-) Station 1 Mar. 10.0 7.8 24.77 7.7 177 Apr. 22.5 G.6 23.69 7.8 81 May 23.0 5.5 16.15 7.8 86 June 28.5 5.1 19.38 7.7 56 July 30.0 4.8 24.77 7.7 61 Aug. 27.0 4.5 22.08 7.7 22 Sep. 26.0 4.9 19.92 7.3 81 Oct. 19.0 6.4 23.16 7.8 59 Nov. 16.5 7.4 25.85 7.8 125 Dec. 10.0 9.2 28.08 7.7 Station 2 Mar. 11.5 8.2 26.92 7. G 122 Apr. 20.5 6.8 27.46 7.7 112 May 25.0 4.4 24.77 7.6 76 June 28.0 3.0 22.62 7.6 61 July 29.5 3.0 21.00 7.6 36 Aug. 29.0 3.2 25.85 7.7 55 Z 'o P. 26.0 4.3 18.85 7.7 25 Oct. 25.0 4.1 22.08 7.6 33 Nov. 16.5 7.2 23.69 7.9 48 Dec. 10.0 9.4 24.23 7.9 42 Station 3 Afar. 12.0 8.6 24.23. 7.9 112 Apr. 20.0 7.8 27.46 7.9 81 .111 a y 24.0 5.4 21.54 7.7 86 June 28.5 3.9 22.62 7.8 84 July 29.5 4.3 24.23 7.7 50 Aug. 28.5 3.7 17.77 7.6 50 Sep. 28.0 4.4 16.1.5 7.3 38 Oct. 21.0 6.4 22.66 7.7 58 Nov. 14.0 8.5 23.16 7.9 55 Dec. 10.0 9.4 18.85 7.8 81 Station 4 Mar. 17.0 7.0 23.69 7.8 61 ADr. 19.0 7.1 25.85 7.7 132 May 22.5 5.8 23.69 7.9 86 June 26.0 5.2 20.46 7.9 112 July 29.5 5.7 32.31 8.1 147 Aug. 29.0 5.7 31.23 7.9 61 Sep. 25.5 5.0 16.69 7.6 25 Oct. 27.0 6.3 22.08 7.7 36 Nov. 18.0 7.4 28.00 8.2 22 Dec. 10.0 9.3 25.31 8.0 38 Station 5 Mar. 18.0 6.8 24.23 7.4 167 Apr. 21.0 6.5 26.38 7.9 112 May 24.5 5.4 26.92 7.8 64 June 28.5 4.2 26.38 7.8 58 July 31.0 4.6 29.08 7.9 61 Aug. 28.5 3.2 27.46 7.6 61 Sep. 25.6 6.2 18.85 7.6 43 Oct. 25.5 4.5 17.23 7.5 61 Nov. 18.5 6.2 15.08 7.7 60 Dec. 12.0 8.6 17.77 7.8 60 (25) -ological data collected at the five Appendix Table D-Hydi Florida Sampling Statioits Bottom DO Salinity Turbidity Month Temp. ('C) (ppm.) 0-0 PH (Cm.) Station 1 Mar. - - - - Apr. 21.5 4.7 19.92 7.4 70 May 25.0 5.7 26.92 7.9 105 June 29.5 6.9 24.77 8.0 1.20 July 30.0 6.3 24.23 7.8 15 5 Aug. 29.0 5.2 15.62 7.5 140 Sep. 28.5 5.3 12.38 7.5 85 Oct. 25.5 3.5 1.08 7.2 70 Nov. 20.0 5.0 1.08 7.5 70 Dec. 15.5 7.0 23.69 8.0 65 Station 2 Mar. - - - Apr. 20.5 3.6 32.31 7.7 90 May 26.0 5.3 33.93 8.0 120 June 27.0 6.5 33.93 9.0 95 July 29.9 5.6 33.39 ". 6 90 Aug. 27.9 6.2 34.47 8.0 90 Sep. 28.0 4.8 24.85 7.6 45 Oct. 25.0 4.8 15.62 7.5 43 Nov. 18.0 5.1 13.46 7. -r) 75 Dec. 16.5 6.1 26.91 7.5 55 Station 3 Mar. - - - - - Apr. 20.8 1.7 30.15 7.0 70 May 25.5 2.5 31.23 7.5 60 June 29.5 1.9 29.62 7.4 75 July 29.5 4.0 32.31 7.5 105 Aug. 31.0 5.3 31.23 7.5 60 Sep. 29.0 4.7 21.54 7.2 45 Oct. 24.5 2.3 16.15 7.0 43 Nov. 17.5 4.1 19.92 7.5 85 Dec. 15.5 5.8 24.23 7.5 65 Station 4 Mar. - - - - - Apr. 20.3 2.9 30.15 7.4 70 May 25.0 3.4 30.69 7.5 76 June 30.0 4.9 30.15 7.6 95 July 29.5 5.2 30.69 7.6 145 Aug. 30.0 5.3 35.54 8.0 150 Sep. 29.0 3.1 23.16 7.5 60 Oct. 24.5 4.4 23.69 7.6 75 Nov. 18.5 5.4 29.62 8.0 80 Dec, 15.0 6.8 26.92 7.6 70 Station 5 Mar. - - - - Apr. 18.6 2.G 29.08 8.0 65 May 25.5 3.6 29.62 7.5 90 June 29.5 7.2 25.31 7.5 90 July 30.0 6.7 29.08 7.7 135 Aug. 30.0 5.4 30.69 7.5 90 Sep. 27.5 4.0 26.92 7.5 75 Oct. 24.5 3.1 17-03 7.2 60 Nov. 18.5 4.8 23.16 7.7 85 Dt,,c. 14.5 6.8 29.62 8.0 127 (2) 6) Appendix Table E-Pesticide -resitille levels found in tAe soft tissue of bhte crabs col.lected hi North Carolina. Ile,,;ticidx levels are expressed in T)pm,. Month Sta. I,ab.Nlo. DDE DDD DDT Dieldrin Mirex March 1 C-36 .063 C90 .170 2 0-17 .084 .195 - 3 C-18 .086 .072 .1.34 .005 4 C-19 .067 .072 .111 - 5 C*21 .122 .087 .099 April 1 C-40 .065 .057 .078 2 C-37 .060 .029 .058 3 C-34 .120 .067 .134 4 C-50 .076 .048 .089 I C-21 0,47 -.099 May I C-47 .043 .026 .055 - - 2 C-33 .099 .188 .213 - - 3 C@41 .076 .052 .080 - - 4 C-22 .53 .090 .173 - - 5 C-42 .051 .024 .051 - - June I C-44 .048 .031 .065 - - 2 C-43 .017 .020 .031 - - 3 C-49 .100 .063 .085 - - 4 C-45 .014 .016 .027 - - 5 C-46 .024 .013 .037 - - July I C-51 .076 .048 .089 - 2. IC-38 .035 .040 .083 3 C-32 .108 .075 .127 4 C-48 .053 .021 .059 5 C-39 .047 .055 .109 August I C-107 .080 .069 .108 - - 2 C-109 .040 .051 .070 - - 3 C-158 .060 .090 .095 - - 4 C-113 .045 .062 .080 - - 5 C-Ill .042 .060 .082 - - Saptember 1 C-103 .075 .080 .095 - - 2 C-115 .060 .060 .085 - - 3 .057 .073 .092 - - 4 C-104 .060 .080 .085 - - 5 4C-110 .051 .070 .082 October I C-163 .022 .035 .030 - 2 C-161 .023 .035 .036 .012 3 C,-'114 .092 .081 .130 - 4 C-153 .042 .032 .036 .020 5 C-1.54 .042 .034 .051 - November I C-162 .623 .035 .025 2 C-160 .038 .039 .036 .005 3 C-156 .068 .026 .035 .008 4 C-155 .018 .014 .020 - 5 0-157 .026 .030 .035 - .020 December I C-181 .01.3 .012 .027 .003 .045 2 C-183 .020 .01.1 .012 .003 - 3 C-179 .020 .014 .023 .004 .045 4 C-182 .020 .0io .025 .002' .030 5 .012 .027 - - (27) Appendix Table F-Pesticide residue levels fou,-izd in the soft tissue of blue crabs coUected in South Carolina. Pesticide levels are expressed ir. ppm. Month Sta. Lab.No. DDE DDD DDT Djeldrin Mirex March I C-16 .095 .107 .247 .112 2 C-15 .134 .085 .110 .089 3 C-13 .096 .149 .172 .074 4 C-14 .086 .126 .162 5 0-12 .153 .117 .@47 .005 - April 1 C-85 .1.13 .134 .120 - .140 2 0-!87 .115 .114 126 .100 3 C-88 .120 .072 .063 - .120 4 C-494 .083 .072 .088 .014 - 5 C-86 .134 .095 .095 - - May 1 C-91 .059 .048 .074 .020 .125 2 C-93 .165 .101 .087 .020 .209 3 C-94 .083 .072 .088 .014 - 4 :C-88 .120 .072 .062, - .179 5 G90 .050 .031 .029 - - June 1 C-97 .082 .107 .128 .014 2 C-96 .050 .129 .106 - 3 C-92 .096 .025 .071 .019 4 C-99 .043 .076 .104 - 5 C-98 .057 .107 .126 - July I C-101 .072 .114 .151 - 2 C-102 .108 .160 .166 - - 3 C-117 .085 .102 .130 - .086 4 C-62 .123 .058 .103 - - 5 C-100 .061 .126 .130 - - August 1 C-63 .092 .051 .065 .004 .150 2 C-66 .108 .072 .083 - .075 8 C-65 .180 .116 .099 .085 4 C-64 .163 .076 .123 - - 5 C-61 .117 .087 .106 - September I C-121 .126 .114 .120 - - 2 C-119 .140 .104 .130 - .080 3 C-118 .095 .110 .105 - .106 4 C-120 .104 .101 .135 - - 6 C-116 .115 .130 .162 - - October I C-141 .020 .029 .033 - - 2 C-138 .048 .096 .108 - - 3 C-139 .030 .040 .051 4 C-140 .050 .064 .068 - 5 0-142 .069 .060 .046 - .030 November 1 C-193 .022 .015 .015 .002 .038 2 192 .024 .016 .027 .002 - 3 190 .017 0.10 .015 - 4 191 .011 .009 .018 - - 5 186 .030 .022 .016 .004 .010 December 1. 187 .012 .010 .012 .005 .010 2 188 .028 .017 .018 - .052 a 186 .030 .010 .014 .002 - 4 189 .015 .011 .01.9 .005 .005 194 .030 .025 .023 - .067 (28) Apper.-jix Table G-Pesticide residue levels -found in the soft tissue of.blue crabs collected in Georgia. Pesticide levels are expressed in pp?)?,. Month Sta. Lab.No. DDE DDD DDT Dieldrin Mirex March 1 C-22 .101 .081. .108 - - 2 C-23 .047 .067 .097 - - 3 C-24 .101 .179 .145 - - 4 C-25 .064 .072 .083 - - 5 C-26 .094 .104 .106 - - April 1 C-6 .082 .101 .134 2 C-7 .073 .036 .106 .006 - 3 C-9 .143 .060 .108 .011 .294 4 C-10 .231 .060 .176 - .308 5 C-8 .075 .075 .165 .010 - May 1 C-2 .055 .068 .109 2 C-I .045 .052 .073 3 C-4 .088 .085 .142 4 C-3 .077 .098 .126 5 C-5 .075 .090 .114 June I C-125 .092 .097 .115 - .165 2 C-126 .085 .090 .120 .004 - 3 C-127 .120 .090 .160 .008 .201 4 C-84 .063 .048 .067 - - 5 IC-83 .072 .047 .058 .005 - July I C-82 .072 .043 .071 - .298 2 C-124 .102 .120 .136 - .120 3 C-73 .120 .102 .160 - .226 4 C-123 .082 .099 .112 - - 5 G-122 .075 .068 .089 - August 1 C-131 .081 .103 .109 - .106 2 C-128 .090 .101 .098 - - 3 C-132 .102 .075 .120 - .103 4 C-129 .120 .108 .125 - .108 5 C-130 .065 .090 .108 - .070 September I C-136 .080 .092 .130 .015 .195 2 C-133 .090 .089 .095 - .080 3 C-1.35 .030 .034 .039 .070 4 G-134 .070 .115 .105 .095 C-137 .072 .085 .120 .105 October 1 C-172 .069 .038 .044 .072 .330 2 C-173 .139 .039 .054 .018 .190 3 C-171 .139 .079 .043 - .038 4 C-169 .015 .057 .048 - 5 -C-170 .038 .025 .029 .015 November I C-197 .040 .023 .037 .025 .389 2 C-196 .038 .016 X18 .014 3 C-199 .078 .060 .063 .012 .140 4 C-198 .024 .023 .060 .030 - 5 G-195 .022 .012 .024 .005 - December 1. C-204 .01.9 .016 .018 .025, .143 2 -C-201 .026 .015 .046 - 209 3 C-203 .072 .030 .062 .005 .150 4 C-202 .043 .030 .093 .030 .112 6 -C-200 .040 .020 .035 .008 - Appendix Table H-Pesticide -residue levels found in the soit tissue of blue crabs collected in Florida. Pesticide levels are expressed in ppm. Month Sta. Lab.No. DDE DDD DDT Dieldrin Mirex April 1 .064 .155 .196 2 .072 .155 .166 3 .046 .060 .114 4. .060 .068 .079 5 .108 .180 .@80 May 1 .055 .068 .090 .070 .084 .102 3 .075 .098 .120 4 .036 .043 .065 5 .114 .096 .117 June 1 .036 .120 .108 2 .048 .060 .076 3 .065 .080 .165 4 .064 .078 .095 .029 .040 .055 July 1 .032 .048 .065 - - 2 .049 .051 .089 - - 3 .068 .095 .128 - - 4 .075 .085 .09G - - 5 .080 .095 .130 - - August 1 .04 8 .072 .099 - - 2 .043 .080 .045 - - 3 .065 .090 .110 - - 4 .055 .082 .098 - - 5 .066 .095 .101 - - September 1 .012 .021. .049 - 2 .023 .039 .068 .00-9 3 .026 .064 .042 .030 4 .044 .096 .117 - 6 .070 .060 .090 - - October 1 .024 .035 .078 .008 .038 2 .042 .042 .036 - .025 3 .021 .058 1038 .028 4 .018 .046 .040 - 5 .030 .029 .029 .015 'November 1 .065 .080 .097 .015 2 .028 .025 .036 .010 3 .020 .025 .045 .005 4 .019 .018 .022 .020 5 .019 .039 .024 - December 1 .044 .03, .101 .1.64 2 .012 .017 .028 .031 3 .010 .012 .018 .010 4 .026 .015 .026 - 5 .027 .032 .036 .040 (30) Descriptions of Stations estuary is an important nursery area for iinniature blue crabs. The mean annual -Yorth Carolina salinity is around 32/,,, and sampling depths were .5 to 8 meters, Station 1. Eastern Channel is located between the inland waterway and Ocean Station 4. Polly River is an estuary in- Isle 13'each and extends 3.0 miles from tersecting Charleston Harbor at the north- ern end and Stono River at the south. The Tubbs Inlet to the Ocean Isle Beach Bridge. rivell proper is about 3.5 miles in length Mean annual salinity is about 32.1.@', and the sampling depths were from I to 5 and terminates @ii a narrow sound filled meters. with marsh islan'ds and a network of wind- ing channels. Mean annual salinities run Station 2. Located where Shallotte around 265@ and sampling depths were I Creek and Saucepan Creek join the Shal- to 5 meters. lotte River at the Shallotte Inlet. Mean Station 5. IVIiale Branch i6 a natural annual salinity is about 33%@ and the samp- connection or cut-off between Coosaw and ling depths were f rom. 1 to 3 meters. Broad Rivers near Beaufort. It is ap- Station 3. The Elizabeth River is a tidal proximately 1/3 of a mile wide and 2 to 7 river about 2 miles long surrounded by meters deep at low water. The tida,l am- extensive marsh. It extends from the In- plitude, runs nearly 2.5 meters and exceeds tracoastal Waterway to the Cape Fear 3 meters on spring tides. This station is River. Mean annual salinity is about 21'/,@ 17 miles from the ocean and salinities are and sampling depths were from 2 to 5 around 20Y,.. meters. Station 4. Located on Stones Bay about Georgia 5.0 miles in from the New River Inlet. Station 1. Located where Grinriball Mean annual salinity is about 23%@ and Greek joins the Skidaway River. Grimball the sampling depths were from I to 3 Creek drains a larcre inarsh area. Skidaway meters. River is part of the Intracoastal Waterway. Station 5. Located adjacent to Core This station was strongly influenced by rainfall and tidal flow. @ampling depths Sound in Jarrett Bay and between Willis- ton and Wade Creeks. Mean annual salin- ed greatly in a small area ranging ity is about 25/1', and sampling depths were from I to 15 meters. f rom I to 3 meters. Station 2. Located where Ashley Creek empties into St. Catherines Sound. Ash- South Carolina ley Creek originates in an extensive marsh. Sampling depths range from 2 to 6 meters. Station 1. Harbor River, a narrow channel winding through marshland, is Station 3. Sapelo River is a large body of water that runs directly into Sapelo located 4.5 miles south of McClellanville and Sound. This station was chosen for col- is tributary to the Intracoastal Wateri vay lectffig disease and parasite samples be- opening into Bulls Bay. This system is a lower distributary of the Santee River cause of the massive mortalities that had Delta with a mean annual salinity of ap- occurred there the two previous years. proximately 25Y,,. Sampling depths ranged Sampling depths varied from 2 to 8 meters. from I to 10 meters. Station 4. Located at the southeast tip Station 2. Wando River is a main branch of St. Simons Island in St. Simons Sound; the area is fed by rivers polluted by indus- of Charleston Harbor and runs northeast- erly from its mouth at the Cooper River tries located in Brunswick. Sampling depths varied from 1 to 12 meters. for about 17.5 miles. The mean annual salinity is around 16%@ and sampling Station 5. Crooked River is the south- depths ranged from 5 to 10 meters. ern-most station in Georgia. The sample area was near Crooked River State Park. Station 3. Point of Pines is located Sampling depths ranged from 2 to 5 along the western shores of North Edisto meters. River about 3 miles from the ocean. This (31) P Florida of Fernandina Beach near the head of Lanceford 'reek, abundant in mud flats Station 1. Florida's southernmost sta- and poorly drained swales; depth 3 to 8 tion site, located 8 miles west of St. Johns meters. Inlet between two small tributarieF, Clap- board Creek and Browns Creek; depth 2 Station 4. Near the ocean in Cumber- t6 6 meters. land Sound between Tiger Creek and Amelia River; bottom type sandy mud; Station 2. In Nassau Sound, near the three main rivers flow into 'Uhis area, the southern tip of Amelia Island; bottom type Jolly, the St. Marys, and the Amelia, creat- sandy mud, continually scoured by rapid ing strong cross currents and extensive flow of water during tidal changes. Two mixing of waters; depth 1 to 5 meters. large rivers drain into this basin, the Station 5. In St. Marys Ri 'er near the Nassau and the South Amelia; depth 5 to v G meters. outflow of Jolly River; Florida's northern- most station joining bou, ndaries with Station 3. Approximately 4 miles west Georgia; depth 3 to 8 meters. (32) 3 6668 14100 0747