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Articles 1351 - 1380 of 1400

Full-Text Articles in Life Sciences

Aspects Of Biodeposition By Oysters And Other Invertebrate Filter Feeders, Dexter S. Haven, Reinaldo Morales-Alamo Jan 1966

Aspects Of Biodeposition By Oysters And Other Invertebrate Filter Feeders, Dexter S. Haven, Reinaldo Morales-Alamo

VIMS Articles

Quantities of suspended matter removed by oysters (Crassostrea virginica) and deposited as feces or pseudofeces varied seasonally, reaching maxima in September. Below 2.8C, measurable quantities were not produced. At certain seasons, levels of suspended solids influenced quantities of biodeposits. Laboratory studies indicated that the oysters on 0.405 hectare of an estuarine bottom may produce up to 981 kg of feces and pseudofeces weekly. Of the particles, 95% were under 3 µ in diameter. all types of algal cells present in the surrounding water were represented. The deposits contained 77–91% inorganic matter, mostly illite, chlorite, and mixed‐layer ...


Oyster Mortality Studies In Virginia .V. Epizootiology Of Msx A Protistan Pathogen Of Oysters, Jay D. Andrews Jan 1966

Oyster Mortality Studies In Virginia .V. Epizootiology Of Msx A Protistan Pathogen Of Oysters, Jay D. Andrews

VIMS Articles

MSX, a pathogen of oysters (Crassostrea virginica), produced a drastic epizootic in high-salinity areas of Chesapeake Bay from 1959 to 1963. The patterns of infection and mortality were determined by imports from disease-free seed-oyster areas. Winter and spring imports became infected in early summer and began dying in late summer. Late-summer imports apparently became infected promptly but infections remained subclinical until the following May. Death rates were highest during warm months but losses occurred throughout the year. MSX was assigned as the cause of a high percentage of deaths by sampling live and dead oysters.

Mortality for the first and ...


Apparatus For Holding The Individual Oysters Under Equal Water Flows, Dexter S. Haven, Reinaldo Morales-Alamo Apr 1965

Apparatus For Holding The Individual Oysters Under Equal Water Flows, Dexter S. Haven, Reinaldo Morales-Alamo

VIMS Articles

No abstract provided.


Studies On Oyster Scavengers And Their Relation To The Fungus Dermocystidium Marinum, Hinton D. Hoese Jan 1964

Studies On Oyster Scavengers And Their Relation To The Fungus Dermocystidium Marinum, Hinton D. Hoese

VIMS Articles

Dermocystidium marinum, a parasitic fungus of oysters, was demonstrated from the stomach of the snail, Urosalpinx cinerea, from the stomach, intestine, and body of three fishes, Gobiosoma bosci, Chasmodes bosquianus, and Opsanus tau, and from the body, especially setae, of two crabs, Neopanope texana and Rhithropanopeus harrisii. All animals containing D. marinum had scavenged oysters infected by the fungus. A few oysters became lightly infected when kept in aquaria with fishes that ·had been fed infected oyster tissue. In one tidal inlet of Chesapeake Bay, Virginia, Eurypanopeus depressus was the most abundant scavenger, followed by Nassarius vibex, Gobiosoma bosci, and ...


Oyster Mortality Studies In Virginia Iv. Msx In James River Public Seed Beds, Jay D. Andrews Jan 1964

Oyster Mortality Studies In Virginia Iv. Msx In James River Public Seed Beds, Jay D. Andrews

VIMS Articles

"MSX," an unnamed pathogen of oysters, caused an epizootic in Chesapeake Bay which removed from production nearly half of Virginia's private oyster-planting acreage between 1959 and 1961. The organism did not appear in James River seed beds .until fall of 1960. A tongueshaped distribution of MSX was apparently related to influx of salt water along the channel. In 1960-61 and 1961-62, infections of MSX appeared at Wreck Shoal in the middle of the seed area in October, and disappeared the following April coincident with lowest salinities. Infection levels were approximately 30 to 35% each year in populations adjacent to ...


Rhynchocoela: Nemerteans From Marine And Estuarine Waters In Virginia, William E. Mccaul Oct 1963

Rhynchocoela: Nemerteans From Marine And Estuarine Waters In Virginia, William E. Mccaul

VIMS Articles

This paper presents twenty-two species of nemerteans collected from various habitats in the York River, the Chesapeake Bay, and the Eastern Shore of Virginia during the summer of l962. For the presentation of supplementary descriptions, this number includes those already reported from the Chesapeake area (Ferguson and Jones, 1949) , besides seventeen species not previously reported from this region and two newly described species.


A Commentary On Claw Deformities In The Blue Crab, Carl N. Shuster, David H.B. Ulmer Jr., Willard A. Van Engel May 1963

A Commentary On Claw Deformities In The Blue Crab, Carl N. Shuster, David H.B. Ulmer Jr., Willard A. Van Engel

VIMS Articles

Throughout history mankind has probably reacted to all natural phenomena by some degree of either attraction or repulsion. Certainly the same objects or phenomena are not viewed exactly alike by all. The rhythmic, as contrasted with discordant, motion, or symmetrical versus non-symmetrical patterns of structure may elicit various feelings in different people. Since natural growth generally produces structural patterns which follow some type of symmetry, this is what we usually expect. While sluggish motion and radial symmetry often are associated, usually animals which dart about or are quick in action have evolved along lines of bilateral symmetry, as have fishes ...


Abundance, Age, And Fecundity Of Shad, York River, Va, 1953-1959, Paul R. Nichols, William H. Massman Jan 1963

Abundance, Age, And Fecundity Of Shad, York River, Va, 1953-1959, Paul R. Nichols, William H. Massman

VIMS Articles

A study of the American shad fishery of the York River Va. during 1959 showed an estimated total catch of 463,000 pounds, a fishing rate of 55.2 percent, and a total population of 839,000 pounds. Additional estimates of catch and effort were used to calculate fishing rate and population size for each year 1953 through 1958. Analyses of scales showed that most shad spawn at 3, 4, and 5 years of age and approximately, 23 percent of the fish caught during the 1957-59 seasons had spawned the previous year. The number of ova produced by. York River ...


The Blue Crab And Its Fishery In Chesapeake Bay Part 2 - Types Of Gear For Hard Crab Fishing, W. A. Van Engel Aug 1962

The Blue Crab And Its Fishery In Chesapeake Bay Part 2 - Types Of Gear For Hard Crab Fishing, W. A. Van Engel

VIMS Articles

During the 90-year history of the Chesapeake Bay blue crab fishery, many types of fishing devices were tried, but only pots, trotlines, and dredges proved suitable, and they emerged as the primary types of gear for catchfng hard crabs. In the early years of the fishery, trotlines with their various modifications were used princip~lly for catching hard crabs in the summer. The Chesapeake Bay crab pot, patented in 1938 and modified only slightly since, gradually replaced the trotline. Pots now account for two-thirds of the Virginia hard crab catch and more than half of the Maryland catch, The dredge ...


Respiration, Electron-Transport Enzymes, And Krebs-Cycle Enzymes In Early Developmental Stages Of The Oyster Crassostrea Virginica, Robert E. Black Aug 1962

Respiration, Electron-Transport Enzymes, And Krebs-Cycle Enzymes In Early Developmental Stages Of The Oyster Crassostrea Virginica, Robert E. Black

VIMS Articles

A marked increase in the rate of respiration during early development has been noted in many different organisms (see Brachet, 1950 ; Boell, 1955). In most cases the changes in respiratory enzymes which might contribute to the respiratory increases have not been fully studied. Of particular interest in this connection are studies which have dealt with enzymes of the tricarboxylic acid (citric acid) cycle, as well as those investigations of the enzymes involved in the transfer of electrons between substrates and oxygen, via the systems which oxidize reduced pyridine nucleotides and succinic acid.


The Concentrations Of Some Enzymes Of The Citric Acid Cycle And Electron Transport System In The Large Granule Graction Of Eggs And Trochophores Of The Oyster, Crassostrea Virginica, Robert E. Black Aug 1962

The Concentrations Of Some Enzymes Of The Citric Acid Cycle And Electron Transport System In The Large Granule Graction Of Eggs And Trochophores Of The Oyster, Crassostrea Virginica, Robert E. Black

VIMS Articles

In an accompanying report Black (1962) has shown that considerable changes in the relative activities of several enzymes of the tricarboxylic acid cycle occur during early development of the oyster. Thus, between the blastula and trochophore stages two enzymes, TPN-specific isocitric dehydrogenase and aipha-keto glutaric dehydrogenase, increase 2- to 3-fold, roughly paralleling the increase in respiration during this same period. Five other enzymes were found not to change appreciably during development to the trochophore. These were: aconitase, succinic dehydrogenase, malic dehydrogenase, DPNH oxidase, and cytochrome oxi dase. Following the trochophore stage cytochrome oxidase decreased somewhat in activity, while the other ...


Oyster Mortality Studies In Virginia: Ill. Epizootiology Of A Disease Caused By Haplosporidium Costale Wood And Andrews, Jay D. Andrews, Johon L. Wood, H. Dickson Hoese Jan 1962

Oyster Mortality Studies In Virginia: Ill. Epizootiology Of A Disease Caused By Haplosporidium Costale Wood And Andrews, Jay D. Andrews, Johon L. Wood, H. Dickson Hoese

VIMS Articles

A short, sharp eplzootic disease of oysters on Seaside of Eastern Shore, Virginia, has been associated with a new pathogen, Haplosporidium costale Wood and Andrews. Native oysters in trays have shown closely timed May-June losses for three consecutive years. Losses at other seasons were small. May-June losses ranged from 12 to 14 percent in 1959 to 36 to 44 percent in 1960. James River oysters moved to Seaside showed higher losses than natives after a year of acclimation. Oysters in Bayside creeks revealed late summer losses caused by Dermocystidimn marinmn Mackin, Owens, and Collier rather than May-June deaths.

The new ...


The Blue Crab And Its Fishery In Chesapeake Bay. Part 2. Types Of Gear For Hard Crab Fishing, W. A. Van Engel Jan 1962

The Blue Crab And Its Fishery In Chesapeake Bay. Part 2. Types Of Gear For Hard Crab Fishing, W. A. Van Engel

VIMS Articles

During the 90-year history of the Chesapeake Bay blue crab fishery, many types of fishing devices were tried, but only pots, trotlines, and dredges proved suitable, and they emerged as the primary types of gear for catching hard crabs. In the early years of the fishery, trotlines with their various modifications were used principally for catching hard crabs in the summer. The Chesapeake Bay crab pot, patented in 1938 and modified only slightly since, gradually replaced the trotline. Pots now account for two-thirds of the Virginia hard crab catch and more than half of the Maryland catch. The dredge, first ...


Sexual Behavior Of The Oyster Drills Eupleura Caudata And Urosalpinx Cinerea, William J. Hargis Jr., Clyde L. Mackenzie Jr. Jul 1961

Sexual Behavior Of The Oyster Drills Eupleura Caudata And Urosalpinx Cinerea, William J. Hargis Jr., Clyde L. Mackenzie Jr.

VIMS Articles

The observations reported herein are part of an extensive study of the biology of Urosalpinx cinerea (Say), the smooth oyster drill, and Eupleura caudata (Say), the rnugh oyster drill, which is in progress at our laboratory. Results of studies of other aspects of the behavior and ecology of these predatory snails will be reported as they become available.

Little is known of the copulatory behavior of dioecious marine gastropods. Though Stauber (1943) reported a partial pairing of E. caudata, pairing of U. cinerea has never been described. Our studies show that pairing of both species is a complex process involving ...


Measurement Of Shell Growth In Oysters By Weighing In Water, Jay D. Andrews Jan 1961

Measurement Of Shell Growth In Oysters By Weighing In Water, Jay D. Andrews

VIMS Articles

Extensive use of a modification of the Havinga method of weighing oysters in water, using a Type K7 T GD Mettler balance with suspension attachments, has shown that weekly weighing of numbered individuals reveals individual differences . in rate of shell deposition which correlate with feeding, parasite infections, etc. The method is quick, sensitive, and accurate.


Seasonal Cycle Of Condition Index On Oysters In The York And Rappahannock Rivers, Dexter Haven Aug 1960

Seasonal Cycle Of Condition Index On Oysters In The York And Rappahannock Rivers, Dexter Haven

VIMS Articles

Five series of studies were made to test for differences in condition index of oysters grown in the York and Rappahannock Rivers. Oysters were cultured in elevated trays and on the bottom from 1956 through 1961. All groups came from a single source and were selected for uniformity in size. Rappahannock oysters showed high indices in late spring and fall with a low in late summer; the level of condition of bottom groups was below that of trays. York River oysters showed a peak of condition in late spring; in most years there was no increase in quality in late ...


The Pound-Net Fishery In Virginia. Part 2. Species Composition Of Landings Reported As Menhaden, J. L. Mchugh Feb 1960

The Pound-Net Fishery In Virginia. Part 2. Species Composition Of Landings Reported As Menhaden, J. L. Mchugh

VIMS Articles

Pound nets have been the most important fishing gear for food fishes in Virginia waters of Chesapeake Bay since 1880 (Reid 1955) and the history of this fishery to a great extent reflects the varying fortunes of the fisheries of that State. Since 1929 the average annual catch in pound nets in Virginia has been about 50 million pounds, roughly 20 percent of which was reported as menhaden. Actually these menhaden include varyint?: quantities of other fish species, sometimes predominantly young food fishes, too small to market as human food. This part of the pound-net catch is sometimes used as ...


Fresh-Water Kill Of Oysters (Crassostrea Virginica) In James River, Virginia, 1958, Jay D. Andrews, Dexter Haven, D. B. Quayle Jan 1959

Fresh-Water Kill Of Oysters (Crassostrea Virginica) In James River, Virginia, 1958, Jay D. Andrews, Dexter Haven, D. B. Quayle

VIMS Articles

Fresh water invaded the upper half of James River seed area in winter and spring of 1958. Many oysters died between 1 May and 15 ·June. On some grounds, salinities did not become suitable until l July when temperature had reached 23°c. Death rates of native oysters were as high as 90 percent.

Oysters exposed to fresh water from midwinter were "conditioned" to a low physiological state as evidenced by absence of heart beat, ciliary motion and mantle sensitivity when first opened. Oysters held in trays at one extremity of the seed area withstood fresh-water conditions similarly to oysters ...


Effects Of Pea Crabs, Pinnotheres Ostreum, On Oysters Crassostrea Virginica, Dexter Haven Jan 1959

Effects Of Pea Crabs, Pinnotheres Ostreum, On Oysters Crassostrea Virginica, Dexter Haven

VIMS Articles

Oysters with and without pea crabs were compared for growth and fatness. Measurements included volume, wet and dry meat weight, and shell cavity volume. Oysters with crabs contained less eat per unit of shell cavity volume than those without crabs but per cent water content was similar. Incidence of pea crabs in the lower James, York and Rappahannock rivers from 1953-1958 varied from 6 to 22 per cent.


Observations On Distribution And Elimination Of Spores Of Nematopsis Ostrearum In Oysters, Sung Yen Feng Jan 1958

Observations On Distribution And Elimination Of Spores Of Nematopsis Ostrearum In Oysters, Sung Yen Feng

VIMS Articles

A non-random distribution of cysts of Nematopsi.s along the mantle margin of oysters was discovered. Sampling sites must be carefully chosen for cornparative studies. When oysters with high and low initial infections of Nematopsis were transplanted into areas of low and high infestation respectively, the transplants attained the characteristic level of inf'ections of native oysters in that area. Presumably a dynamic equilibrium of elimination and reinfection of the parasite was reached. Spores discharged from living oysters may infect crabs.


The Blue Crab And Its Fishery In Chesapeake Bay. Part 1. Reproduction, Early Development, Growth And Migration, W. A. Van Engel Jan 1958

The Blue Crab And Its Fishery In Chesapeake Bay. Part 1. Reproduction, Early Development, Growth And Migration, W. A. Van Engel

VIMS Articles

Blue Crabs are abundant on the East And Gulf Coasts of North America, on the East Coast of South America, and have been reported from France, Holland, and Denmark, and the East Coast of the Mediterranean. In Chesapeake Bay, fishing has been intensive for over 80 Years; in the last 10 years, the average annual production has been about 60 million pounds, valued about three million dollars, approximately two-thirds of the entire United States blue crab harvest.


Survival And Growth Of Venus Mercenaria, Venus Campechiensis, And Their Hybrids In Suspended Trays And On Natural Bottoms, Dexter Haven, Jay D. Andrews Jan 1957

Survival And Growth Of Venus Mercenaria, Venus Campechiensis, And Their Hybrids In Suspended Trays And On Natural Bottoms, Dexter Haven, Jay D. Andrews

VIMS Articles

In. the course of laboratory experiments on spawning of mollusks and propagation of larvae and young, Loosanoff and Davis (1950) of the Milford Laboratory of the U. S. Fish and Wildlife Service crossed the southern hard-shell clam, Venus campechiensis Gmelin, with the northern species Venus mercenaria Linne (Loosanoff, personal communication). ·To determine the ecological adaptations of the hybrids, groups of the parent species and their reciprocal hybrids were sent for testing to six laboratories from Maine to Florida, The northern quahog or hard-shell clam inhabits the shores of the Western.Atlantic from·the. Gulf·of St. Lawrence to Florida and ...


Some Effects Of High-Frequency X-Rays On The Oyster Drill Urosalpinx Cinerea, William J. Hargis Jr., Mary F. Arrighi, Robert W. Ramsey, R. Williams Jan 1957

Some Effects Of High-Frequency X-Rays On The Oyster Drill Urosalpinx Cinerea, William J. Hargis Jr., Mary F. Arrighi, Robert W. Ramsey, R. Williams

VIMS Articles

Scientists of ·the.Department of Agriculture (Bushland et al. 1955) recently announced the successful eradication of the screw-worm, Callitroga hominivorax, from the Dutch Island of Curacao. This was accomplished by releasing x-ray steralized males, which competed successfully with normal indigenous males for the females. After such matings the monogamous females deposited only sterile egg masses. Although several releases, Were necessary, eventually no fertile eggs Were detected at any of the.numerous observation points. Subsequent checks failed to reveal any live flies.

Because existing information concerning ecology and reproduction of drills appeared favorable, our group was encouraged to investigate this technique ...


History Of Virginia's Commercial Fisheries: Neglected Historical Records Throw Light On Today's Problems, J. L. Mchugh, Robert S. Bailey Jan 1957

History Of Virginia's Commercial Fisheries: Neglected Historical Records Throw Light On Today's Problems, J. L. Mchugh, Robert S. Bailey

VIMS Articles

As the Susan Constant, the Godspeed, and the Discovery made their way through Hampton Roads and up the James River toward Jarnestown in 1607, they traversed a 15-mile stretch of water that was to play an important part in the history and economy of Virginia. Beneath these pleasant waters, and sometimes forming reefs that were awash at low tide, lay the most prolific natural oyster beds in the world. Three hundred and fiftv years later these grounds still provide the seed that makes Virginia's oyster industry supreme, producing about one-quarter of the nation's supply of these delicious mollusks ...


The Survival And Growth Of South Carolina Seed Oysters In Virginia Waters, Jay D. Andrews, J. L. Mchugh Jan 1957

The Survival And Growth Of South Carolina Seed Oysters In Virginia Waters, Jay D. Andrews, J. L. Mchugh

VIMS Articles

Most of the seed oysters planted on private grounds along the Atlantic Coast of the United States are obtained from public seed beds. The supply depends largely upon a wild crop over which there is little control. It is to be expected, perhaps, that the quantity of seed available at various localities along the coast is in proportion to the duration of the warm season. It follows that oystermen are usually searching southward for their supply of seed and the ramifications of this hunt are complex and ever changing.


Trapping Oyster Drills In Virginia Iii. The Catch Per Trap In Relation To Condition Of Bait, J. L. Mchugh Jan 1957

Trapping Oyster Drills In Virginia Iii. The Catch Per Trap In Relation To Condition Of Bait, J. L. Mchugh

VIMS Articles

In the course of trapping experiments previously described (Andrews 1955, McHugh 1955), a question arose concerning deterioration of bait with time. It is fairly obvious to those who fish the traps that the condition of the bait changes. The smallest oysters die first, through predation by drills, crabs, and other enemies, and through smothering in the muddy bottom. Barnacles and other organisms on the shells also die from various causes. The valves of the dead oysters soon separate, and some are lost through meshes of the trap, so that the volume of bait also decreases. Stauber (1943) found that efficiency ...


Oyster Mortality Studies In Virginia. Ii. The Fungus Disease Caused By Dermocystidium Marinum In Oysters Of Chesapeake Bay, Jay D. Andrews, Willis G. Hewatt Jan 1957

Oyster Mortality Studies In Virginia. Ii. The Fungus Disease Caused By Dermocystidium Marinum In Oysters Of Chesapeake Bay, Jay D. Andrews, Willis G. Hewatt

VIMS Articles

A high death rate of oysters in Virginia waters during the warm months of summer and fall was reported by Hewatt & Andrews (1954b). One of the most important causes of this warm-season mortality is the fungus Dermocystidium marinum, a pathogen discovered in the Gulf of Mexico by Mackin, Owen & Collier (1950). The fungus is found along the coast of the Western Atlantic from Delaware Bay to Florida and on the coast of the Gulf of Mexico from Florida to Texas.

In Chesapeake Bay the disease was studied for pathogenicity to oysters, seasonal occurrence, distribution, and its effect on the oyster ...


Distribution, Growth, And Availability Of Juvenile Croaker, Micropogon Undulatus, In Virginia, Dexter S. Haven Jan 1957

Distribution, Growth, And Availability Of Juvenile Croaker, Micropogon Undulatus, In Virginia, Dexter S. Haven

VIMS Articles

The shore fisheries of Virginia have long produced an important part of the nation's seafood supply. The principal fishing gears, the pound net and the haul seine, take a variety of fishes, of which the most important is the croaker, Micropogon undulatus. Prior to World War II from one-quarter to one-half of the landings of food fishes in Virginia consisted of croakers, and the catch reached a maximum in 1945 when more than 55 million pounds were landed (Fig. 1). Since that time the croaker catch has decreased precipitously, and in 1952, the latest year for which records are ...


Trapping Oyster Drills In Virginia I. The Effect Of Migration And Other Factors On The Catch, Jay D. Andrews Aug 1955

Trapping Oyster Drills In Virginia I. The Effect Of Migration And Other Factors On The Catch, Jay D. Andrews

VIMS Articles

Virginia oystermen have tried trapping of drills as a control measure and discarded it as ineffective and too costly. It is true that their efforts were sporadic and lacking in persistence, and the effects of their trapping were not adequately appraised. They expected returns in the form of increased yields too quickly. Nevertheless, these brief trials have convinced even the most progressive oystermen that trapping· drills is not the answer to their predation problem. In Chesapeake Bay, consequently, no conscious effort is made to control drills. Oyster grounds are often allowed to lie fallow for several year's, a practice ...


Temperature Control Experiments On The Fungus Disease, Dermocystidium Marinum, Of Oysters, Willlis G. Hewatt, Jay D. Andrews Aug 1955

Temperature Control Experiments On The Fungus Disease, Dermocystidium Marinum, Of Oysters, Willlis G. Hewatt, Jay D. Andrews

VIMS Articles

In 1950 Mackin, Owen, and Collier described a fungus parasite, Dermocystidium marinim, found in oysters of Louisiana coastal waters. Since that, time numerous studies have been conducted on the nature of the fungus and its effects upon the host. It has been definitely established that the pathogen is the main contributor to the causes of mortality of oysters in some areas. Ray and Chandler (1955) have adequately reviewed the literature on the subject.

Among the various observations that have been made on the fungus disease there is very positive evidence that the incidence and intensity of the infection are primarily ...