Showing papers in "Chesapeake Science in 1965"
TL;DR: The family Ostreidae consists of a large number of edible and nonedible oysters, confined to a broad belt of coastal waters within the latitudes 64° N. and 44° S, with few exceptions oysters thrive in shallow water.
Abstract: NOTE.-Approved for publication April 24, 1964. The family Ostreidae consists of a large number of edible and nonedible oysters. Their distribution is confined to a broad belt of coastal waters within the latitudes 64° N. and 44° S. With few exceptions oysters thrive in shallow water, their vertical distribution extending from a level approximately halfway between high and low tide levels to a depth of about 100 feet. Commercially exploited oyster beds are rarely found below a depth of 40 feet. The· name "Ostrea" was given by Linnaeus (1758) to a number of mollusks which he described as follows: "Ostrea. Animal Tethys, testa bivalvis inaequivalvis, subaurita. Cardo edentulus and fossula cava ovata, striisque lateralibus transversis. Vulva anusve nullus." The name Tethys (from Greek mythology and also refers to the sea) applies to the type of marine animals, living either within the shells or naked, that Linnaeus listed under a general name "Vermes" which includes worms, mollusks, echinoderms, and others. The translation of Linnaeus' diagnosis reads as follows: Shell bivalve, unequal, almost ear-shaped. Hinge toothless, depression concave and oval-shaped, with transverse lines on the sides. No vulva or anus. Taxonomic characters _ SheIL _ Anatomy _ Sex and spawnlng _ Habitat _ Larvll! shell (Prodlssoconch) _ The genera of living oysters _ Genus 08trea _ Genus Cra8808trea _ Genus Pycnodonte _ Bibliography _ Page
519 citations
TL;DR: A study was made on mysid species composition, reproductive periods, and diurnal and seasonal abundance in Indian River Inlet, Delaware as mentioned in this paper, where Neomysis americana was present in the surface plankton throughout the year and was the dominant species averaging 80% of the mysid population.
Abstract: A study was made on mysid species composition, reproductive periods, and diurnal and seasonal abundance in Indian River Inlet, Delaware. Neomysis americana was present in the surface plankton throughout the year and was the dominant species, averaging 80% of the mysid population. This species was most numerous in surface waters during hours of darkness and seasonally was most abundant from April through September. It may possibly produce three generations per year—two short-lived summer generations and a longer-lived winter generation. Mysidopsis bigelowi was also present through the year. It averaged 17% of the mysid population and was sporadically abundant from September through February. It reproduces from April through November. Metamysidopsis munda andGastrosaccus dissimilis were infrequently collected and together averaged less than 3% of the mysid population. They were encountered only in late summer and fall, during which time egg-bearing females or larvae were observed. Mysids are extremely abundant in these Delaware waters and there is evidence that they serve as an important source of food for fish populating these inshore waters during the warmer months.
47 citations
TL;DR: The Patuxent River Estuary was sampled in mid-stream at 12 stations which were distributed from a point near solomons, Maryland, to Milltown Landing upstream in three transects, which spanned the river in the vicinity of Chalk Point as mentioned in this paper.
Abstract: Rates of production were measured at 22 stations located in a 29-mile segment of the Patuxent River Estuary. The river was sampled in mid-stream at 12 stations which were distributed from a point near solomons, Maryland, to Milltown Landing upstream. Thirteen of the stations were arranged in three transects, which spanned the river in the vicinity of Chalk Point. Standing crops of chlorophyll and rates of photosynthesis were measured at a depth of 1.0 meter on 14 cruises spaced over a 23-month, interval. Concentrations of chlorophyll, and coefficients of carbon assimilation and light extinction were employed to convert estimates at a depth of 1.0 meter to rates of production for the entire water column. Both salinity and thickness of the cuphotic layer showed a considerable gradient in the study area. Salinity increased threefold and thickness of the euphotic zone increased fivefold at the downstream end. The gradient was steepest in the study area upstream of the bridge at Benedict, Maryland. Concentrations of chlorophyll were related to season and position in the estuary. They ranged from 33.3 mg/m3 in October to 3.7 mg/m3 in December, the amplitude being largest at the upstream end of the study area. Average concentration at Station 1 was only 1/3 of the concentration 20 miles upstream at Station 22. The gradient was steeper upstream from the bridge at Benedict. Chlorophyll was least uniformly distributed, in the water column immediately downstream from the bridge. Photosynthetic activity of chlorophyll, at probably subsaturation light intensity, ranged from a mean of 5.21 in August to 1.09 in December. The average for all cruises, when corrected rected to saturation intensities of light, was near a widely accepted value for rates of carbon assimilation per unit of chlorophyll. Rates of carbon assimilation ranged from 2.3 to I48.5 mgC/m3/hr. The months from June through October were the most productive in 1963. However, the Spring of 1964 was con. siderably more productive than was the preceding year, suggesting that the productive period is of longer duration in some years. Seasonal trends in productivity were similar at all stations along a 29-mile segment of the river. The downstream end was only 1/3 as productive on a per-unit-volume basis. Despite the larger rates of production at the upstream end of the study area, the region was least productive per unit of area, owing to the shallowness of the euphotic zone. Mean daily rates for the year were 1.2 gC/m2 for the upstream area and 1.8 gC/m2 for the area downstream from the bridge. The limitations of the computations for the highly turbulent upstream area are discussed.
46 citations
TL;DR: In general, fishes which lead a comparatively sedentary existence possess fewer erythrocytes and less hemoglobin per unit volume of blood than the more active types.
Abstract: Mean erythrocyte number per mm3 of blood among nine species of fishes studied ranged from 680,000 for toadfish to 4,120,000 for white perch. Intermediate values were obtained for eel (2,020,000), searobin, flounder, blackfish, puffer, scup, and bluefish (3,830,000) in that order. In general, fishes which lead a comparatively sedentary existence possess fewer erythrocytes and less hemoglobin per unit volume of blood than the more active types. Within each species, a statistically significant correlation exists between erythrocyte number and hemoglobin content.
45 citations
TL;DR: The histopathology of Crassostrea virginica parasitized by the sporocysts of Bucephalus sp.
Abstract: The histopathology ofCrassostrea virginica parasitized by the sporocysts ofBucephalus sp. is studied. Unlike the condition reported inC. virginica parasitized byB. cuculus further south along the Atlantic and Gulf coasts, the primary site of infection in oysters taken during June and July, 1964, from Ninigret Pond, Washington County, Rhode Island, is the digestive gland rather than the gonads. The young sporocysts are carried to the intertubular spaces in the digestive gland from the gut via blood vessels. Destruction of the digestive diverticula is believed to have resulted from both mechanical pressure and physiological degradation. Only in heavy and older infections are large numbers of sporocyst branches found in the gonads. Ova present in parasitized ovaries are reabsorbed. In extremely heavy infections, sporocysts are found in the palps, gills, and mantle in addition to the digestive gland and gonads. In the first three structures, destruction appears to be by mechanical pressure alone.
42 citations
TL;DR: Hatching mechanisms were investigated in the blue crab and in its egg- and gill-parasite, the nemerteanCarcinonemertes carcinophila, collected in the southern Chesapeake Bay area.
Abstract: Hatching mechanisms were investigated in the blue crab,Callinectes sapidus, and in its egg- and gill-parasite, the nemerteanCarcinonemertes carcinophila, collected in the southern Chesapeake Bay area.
38 citations
TL;DR: Dermocystidium marinum is a pathogen which kills oysters in Chesapeake Bay from July through October as mentioned in this paper. The fungus proliferates readily only at temperatures above 25°C but overwinters in oysters as sub-clinical cases.
Abstract: Dermocystidium marinum is a pathogen which kills oysters in Chesapeake Bay from July through October. The fungus proliferates readily only at temperatures above 25°C but overwinters in oysters as sub-clinical cases. Experiments were conducted in Nature to demonstrate the effects of proximity of infected oysters on epizootiology in isolated disease-free populations. Prevalence ofDermocystidium in the York River was moderate in 1957, heavy in 1959, and extremely low in 1963. In 1957, with 40 feet of isolation, groups mixed with infected oysters showed large increases in deaths and prevalences over controls. In 1959, the fungus was so widely prevalent in York River during a long hot summer that relatively minor reductions in death rates were obtained by 50 feet of isolation. In 1963, with the fungus nearly absent, a failure in laboratory infection techniques caused late timing of the experiment, and results were inconclusive. A new disease caused by “MSX”, a protistan parasite, developed high prevalences in the 1963 lots. This organism, by destroying oyster, populations in high-salinity waters (above 15‰ in late summer) has effectively reducedDermocystidium to a minor role as an oyster pathogen in lower Chesapeake Bay. Losses fromDermocystidium in Chesapeake Bay are dependent upon duration of warm seasons and survival of cases through winter. MSX, is slightly more sensitive to low salinities but much more tolerant of low temperatures thanDermocystidium. The decline ofDermocystidium with the disappearance of oyster populations suggests that the pathogen may be dependent solely upon transmission from oyster, to oyster.
35 citations
TL;DR: Of the 29 species studied, 11 are perennial, 6 occur in three seasons, 7 in two seasons, and 5 in one season only, the appearance and disappearance of these algae are closely related to the changes in temperature of the surface water.
Abstract: Semi-monthly (monthly in winter) studies of the reproductive cycles of 8 benthic Chlorophyta, 3 Phaeophyta, and 18 Rhodophyta were carried out over a period of three years at three different localities in the lower Chesapeake Bay. Of the 29 species studied, 11 are perennial, 6 occur in three seasons, 7 in two seasons, and 5 in one season only. The appearance and disappearance of these algae are closely related to the changes in temperature of the surface water. The annual surface water temperature gradient is 25.6'C and the surface water salinity gradient is 6.2%,. The phenological records for these algae show that the climax of reproductive activity for most of the taxa studied is in summer and early autumn. During that period all Chloro- phyta produce swarmers, the phaeophyte Punctaria plantaginea has plurilocular reproductive organs, and all Florideophyceae develop either carposporangia or spermatangia, or both. The Phaeophyta Petalonia fascia and Scytosiphon lomentaria, as well as the Rhodophyta Porphyra leucosticta and P. umbilicalis, release their reproductive cells in the spring. Most Florideophyceae pass the winter in the tetrasporophytic stage or as a sporeling. Like most of the Chlorophyta and the 3 Phaeophyta, these species have an annual cycle. In some of the Ceramiales however, i.e. Ceramium rubrum, Grinnellia americana, Poly- siphonia harveyi, and P. nigrescens, gametophytic plants and tetrasporophytic plants are present at the same time in two different periods of the year. These algae seem to be biennial rather than annual.
30 citations
TL;DR: Bottle collectors were placed in the Tred Avon River, Maryland, during 1961, 1962, and 1963, to obtain information on the setting of bivalves.
Abstract: Bottle collectors were placed in the Tred Avon River, Maryland, during 1961, 1962, and 1963, to obtain information on the setting of bivalves. The bottle collector was an economical and efficient tool for obtaining and studying newly metamorphosed invertebrates in shallow estuarine waters. Seven bivalve species were caught on or in these bottles and the seasonal setting patterns of five species were observed. Of these species,Mya arenaria andMacoma balthica appeared to have dual spawning cycles each year, whileBrachidontes recurvus, Macoma phenax, andMulinia laterali had a single annual spawning cycle.
30 citations
TL;DR: Effects of carbohydrate supplements on shell and tissue (meats) growth of the oysterCrassostrea virginica were evaluated by laboratory studies and had no detectable effect on shell or meat development.
Abstract: Effects of carbohydrate supplements on shell and tissue (meats) growth of the oysterCrassostrea virginica were evaluated by laboratory studies. During spring, the addition of about 5 ppm cornstarch or wheat flour to York River water flowing at optimum rates had no detectable effect on shell or meat development. Similar studies in fall resulted in a significant increase in tissue weights of oysters but no effect on shell size. Tissue development was inhibited if the water supply was restricted or if the inflowing water was initially passed over a large group of actively feeding oysters, (“pre-filtered”). Under these conditions wheat or cornstarch at about 5 to 32 ppm partially or wholly compensated for effects of reduced flows or pre-filtered water on meat development. Effects on shell size were inconclusive. Concentrations of 2 to 5 mg/l dextrose added to inflowing water had no influence on shell or tissue growth. At 34 mg/l there was a significant effect on meat development, but no detectable effect on shell measurements. The study suggests that under estuarine conditions, tissue weights of oysters may beinfluenced by quantities of starch in planktonic algal cells rather than by the species or volume of plankters ingested.
29 citations
TL;DR: Larvae ofRangia cuneata were raised from eggs in laboratory cultures and found that both anterior and posterior shoulders were rounded, and an apical flagellum was conspicuous on swimming larvae.
Abstract: Larvae ofRangia cuneata were raised from eggs in laboratory cultures. Lengths increased from 75 to 175 μ during a seven-day larval life. Height varied from 5 to 20 μ less than length, and thickness 45 to 65 μ less than length. The straight-hinge line was 55 to 60 μ long. A round inconspicuous umbo appeared when larvae were about 120 to 130 μ long. Both anterior and posterior shoulders were rounded. An apical flagellum was conspicuous on swimming larvae. Neither eye spots nor hinge teeth were observed in larvae.
TL;DR: B. truncata larvae are nearly round in appearance with a dark band around the margin of the shell, and metamorphosis occurs when larvae reach a length of 250–315 μ.
Abstract: B. truncata larvae are nearly round in appearance with a dark band around the margin of the shell. The shell is faintly pink near the umbo and at the ventral margin of large larvae. Two interlocking hinge teeth are present in each valve of larvae 70 μ in length or larger. One tooth is about 25 μ long while the other three are 5–10 μ. Straight hinge larvae measure 55–95 μ in length with a straight hinge line about 45 μ long. Height is 0–10 μ less than length, and thickness 20–25 μ less. The umbo is a rounded knob giving larvae a circular appearance and is present in larvae from 85–315 μ in length. In umbo larvae, height is 0–20 μ less than length, and thickness 25 to 80 μ less. Gills are formed before the loss of the velum, and metamorphosis occurs when larvae reach a length of 250–315 μ.
TL;DR: Twenty species of planktonic fish eggs and larvae were identified from 75 surface plankton tows made at river, bay, and ocean locations in the Sandy Hook estuary, with winter flounder most ubiquitous and exhibited a marked diel variation in abundance.
Abstract: Twenty species of planktonic fish eggs and larvae were identified from 75 surface plankton tows made at river, bay, and ocean locations in the Sandy Hook estuary. A gradual increase in the number of species through the spring to a peak in the summer was followed by a decline in the fall and winter. Seventeen species were collected at a location where the Navesink River joins with Sandy Hook Bay. Seven species: American eel, Atlantic herring, American sand lance, winter flounder, bay anchovy, northern pipefish, and Atlantic silverside made up 98$ of all larvae collected. Winter flounder were most ubiquitous and exhibited a marked diel variation in abundance. The most abundant eggs were those of searobin and Atlantic menhaden. Larvae of several species were collected whose adults are either summer or winter visitors to inshore waters.
TL;DR: Follicle cell inclusions and other cells observed in the gonad are discussedAlong with their seasonal changes, more gametes are formed during the autumn or primary period of maturation than during the spring or secondary period.
Abstract: Samples of three year-classes of the soft-shelled clam,Mya arenaria, were dredged at approximately two-week intervals from the mouth of the Patuxent River, Maryland. Changes in gonadal development were noted from histologically prepared sections of male and famale clams. Two separate periods of gametogenesis were noted. More gametes are formed during the autumn or primary period of maturation than during the spring or secondary period. Clams as small as 25 mm in shell length were found to contain mature gametes. Follicle cell inclusions and other cells observed in the gonad are discussed along with their seasonal changes.
TL;DR: Five species of caprellid amphipods occur in Virginia waters: Aeginina longicornis, Hemiaegina minuta, Paracaprella tenuis, Caprella equilibria, and Caprella geometrica.
Abstract: Five species of caprellid amphipods occur in Virginia waters:Aeginina longicornis, Hemiaegina minuta, Paracaprella tenuis, Caprella equilibria, andCaprella geometrica. Though all are offshore species, the latter three commonly occur within Chesapeake Bay.Deutella abracadabra is placed as a juniro synonym ofParacaprella tenuis and the nameCaprella geometrica is assigned to the “acutifrons” form found along the Atlantic and Gulf of Mexico coasts of the United States.
TL;DR: It is suggested that the use of organ weight: body weight ratios may be valuable in evaluating the relationship between certain experimental situations and the biological response of a test organism.
Abstract: The following were recorded for 17 Mongolian gerbils,Meriones unguiculatus, which varied in weight between weanling size and almost 100 grams: body lengths, body weights, organ weights of the thyroid, kidney, adrenal, brain, pituitary, lung, testis, spleen, heart, eye, and liver. Results were analyzed graphically and statistically. The thyroid, kidney, adrenal, brain, pituitary, lung, and eye weights vary with respect to body weight in an allometric fashion. The heart, spleen, and body length vary with respect to body weight in a linear manner, following the ordinary equationy=a+bx, wherey is the organ weight in milligrams or the body length in millimeters andx is the body weight in grams. The prediction equation which best expresses the relationship of the testis, and the liver to body weight is logy=a+x logb, wherey is the organ weight andx is the body weight, It is suggested that the use of organ weight: body weight ratios may be valuable in evaluating the relationship between certain experimental situations and the biological response of a test organism.
TL;DR: In this paper, the authors reported that the southern limit of the periwinkle Littorina littorea is correlated with water mean isothern of 21°C in the warmest month.
Abstract: The common periwinkle,Littorina littorea, is reported from Ocean City, Maryland, and its southern spread is reviewed. A southward flowing longshore current has assisted its southward spread. The southern limit of this species is correlated with water mean isothern of 21°C in the warmest month on both sides of the Atlantic. This limit may be expected to fluctuate with yearly variations in coastal water temperatures.
TL;DR: The distribution of aquatic vascular plants in two transition areas was studied on the South River, an estuarine branch of the Chesapeake Bay located in Anne Arundel County, Maryland (N 38°54′, W 76°20′) as discussed by the authors.
Abstract: The distribution of aquatic vascular plants in two transition areas was studied on the South River, an estuarine branch of the Chesapeake Bay located in Anne Arundel County, Maryland (N 38°54′, W 76°20′). One transition area was near the mouth of the river, where salinities were constantly high due to the proximity of Chesapeake Bay. The other area was at the headwaters of the river, where salinities were lower and without diurnal variation. Temperature, pH, surface currents, and tide levels were measured. Laboratory analyses included three of the major cations in the water, calcium, sodium, and potassium. The dominant species at the mouth of the river wereMyriophyllum spicatum, Potamogeton perfoliatus, Elodea Nuttallii, andSpartina alterniflora. The dominant species found at the headwaters wereElodea canadensis, Typha angustifolia, Pontederia lanceolata, Peltandra virginica, and species of the genusSagittaria.
TL;DR: In this paper, 30 different species of copepods were found in inner continental shelf waters off Virginia from December 1959 through November 1960, and the range of surface water temperature during this period was 25°C (1.6 to 26.6°C).
Abstract: Thirty different species of copepods were found in inner continental shelf waters off Virginia from December 1959 through November 1960. The range of surface water temperature during this period was 25°C (1.6 to 26.6°C). Most of the copepods were colder water forms whose relative abundance throughout the year was similar to that observed by other investigators for the Atlantic coast north of Cape Hatteras. Species of tropical origin were relatively scarce, probably limited by the low winter-spring temperatures. Numerous other crustacean plankters were identified, some to species; decapod larvae were most numerous from April through June. The mean annual displacement volume of total zooplankon, excluding the data for August and September when coelenterates, ctenophores, and tunicates were particularly abundant, was 9.5 ml per 20-minute half-meter-net haul.
TL;DR: Herbicides tested were principally 2,4-D formulations which showed promise of effectively controlling Eurasian watermilfoil (Myriophyllum spicatum L.), an aquatic perennial, which recently has infested much of Chesapeake Bay and its tributaries.
Abstract: Caged blue crabs (Callinectes sapidus), eastern oysters (Crassotrea virginica), softshell clams (Mya arenaria), and various species of fish were exposed experimentally to different concentrations of herbicides in the field in Maryland and Virginia tidewaters to determine possible toxicity effects. Herbicides tested were principally 2,4-D formulations which showed promise of effectively controlling Eurasian watermilfoil (Myriophyllum spicatum L.), an aquatic perennial, which recently has infested much of Chesapeake Bay and its tributaries.
TL;DR: A screen is described which successfully excludes jellyfish and ctenophores from Clarke-Bumpus plankton samples and possible avoidance by copepods of the plankton sampler because of the screen was tested for.
Abstract: A screen is described which successfully excludes jellyfish and ctenophores from Clarke-Bumpus plankton samples. Possible avoidance by copepods of the plankton sampler because of the screen was tested for by analysis of variance of paired tows made with and without the screen. Avoidance could not be demonstrated.
TL;DR: In this paper, twenty-five mammal species are listed from Assateague Island, off the Atlantic Coast of Maryland and Virginia, of which 11 are native land species, 6 are feral or semi-feral forms introduced by man, and 8 are marine.
Abstract: Twenty-five mammal species are listed from Assateague Island, off the Atlantic Coast of Maryland and Virginia, of which 11 are native land species, 6 are feral or semi-feral forms introduced by man, and 8 are marine. The land species are discussed in relation to their habitats which include coastal dunes, fresh and salt water marshes, swamps and forests.
TL;DR: The mineral composition of the Eurasian water milfoil,Myriophyllum spicatum L., in Maryland was investigated to determine the feasibility of its use as a supplement or substitute for commercial fertilizer.
Abstract: The mineral composition of the Eurasian water milfoil,Myriophyllum spicatum L., in Maryland was investigated to determine the feasibility of its use as a supplement or substitute for commercial fertilizer. From June 1962 to January 1963, samples were collected and analyzed from one freshwater and four estuarine habitats.
TL;DR: In this paper, an extratropical storm surge prediction scheme is derived empirically for a station at each end of the Chesapeake Bay by using meteorological observations with various time lags at three stations.
Abstract: An extratropical storm surge prediction scheme is derived empirically for a station at each end of the Chesapeake Bay. The regression equations, which are determined by the multiple correlation-screening process, give an interpolation of the wind field over the Bay by using meteorological observations with various time lags at three stations. Practical prediction equation, each containing six terms, are presented for Baltimore and Hampton Roads storm surges. The Predictors for the Baltimore storm surge have time lags of twelve hours or more whereas those for the hampton Roads storm surge have lags of six hours or more. Tests on independent data show root-mean-square errors of 0.7 feet and 0.5 feet, respectively, for Baltimore and Hampton Roads.
TL;DR: Catch data logged by charter boat captains fishing off Virginia's Eastern Shore from 1955 through 1962 reflect seasonality, migrational patterns, and population trends of species caught as mentioned in this paper, and a discussion of factors affecting catch rate data is presented and related to these charter boat catches.
Abstract: Catch data logged by charter boat captains fishing off Virginia's Eastern Shore from 1955 through 1962 reflect seasonality, migrational patterns, and population trends of species caught. Nineteen percent of 2,369 trips recorded were for offshore “big game” species, 31% of the trips were for inshore “big game”, species, and 50% of the trips were for the smaller game fishes. Seasonal patterns and catch data for bluefish, cobia, dolphin, weakfish, kingfish, Atlantic croaker, black and red drum, little tuna, Atlantic bonito, bluefin tuna, white marlin, summer flounder, and black sea bass are given. A discussion of factors affecting catch rate data is presented and related to these charter boat catches.
TL;DR: Previous comparisons of free amino acids and small peptides from the adductor muscles of oysters to experimental stocks from Delaware Bay, Long Island Sound, Louisiana, Virginia, and several sections of the Chesapeake Bay are extended.
Abstract: This paper extends previous comparisons of free amino acids and small peptides from the adductor muscles of oysters to experimental stocks from Delaware Bay, Long Island Sound, Louisiana, Virginia, and several sections of the Chesapeake Bay. A modified technique, adapted from thin-layer chromatography and used in this study, is described.
TL;DR: A method of gonadal biopsy is described here whereby a tissue specimen of the gonad is obtained from a live fish for sex determination using a pair of serrated alligator-jawed forceps.
Abstract: There is no practical and exact way of telling the sex of the striped bass,Roccus saxatilis (Walbaum), from external characteristics since this species does not exhibit sexual dimorphism, except when they are running ripe. A method of gonadal biopsy is described here whereby a tissue specimen of the gonad is obtained from a live fish for sex determination. A pair of serrated alligator-jawed forceps is used as the tool for obtaining the gonadal tissue via the sterile urogenital tract.