Aquaculture and Fisheries Commons^™

Molting In The Mature Female Blue-Crab, Callinectes-Sapidus Rathbun, Kirk J. Havens, Jr Mcconaugha

VIMS Articles

The present study examined the hypothesis that mature female blue crabs, Callinectes sapidus, do not enter a terminal anecdysis. Induced molting via eyestalk ablation, size frequency distributions, gonad development and limb regeneration indices from field collected animals are used as indicators of potential post maturity molts. Eyestalk ablation of 15mature females resulted in ecdysis in II individuals approximately 51 days (standard error = 0.64) after ablation, indicating a physiological ability of mature females to complete ecdysis. Analysis of size frequency distributions from catch data indicated two distinct shifts from smaller to larger females, one in early spring and a second …

Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia, Ej Olmi, J Van Montfrans, Rn Lipcius, R J. Orth, Pw Sadler

VIMS Articles

Blue crab, Callinectes sapidus, megalopae and juveniles were sampled in the plankton and on natural (grassbeds) and artificial settlement substrates (collectors) at two sites in each of two areas of a lower Chesapeake Bay tributary (York River, Virginia) to examine spatial variability in blue crab recruitment. Spatial patterns of abundance were not consistent across habitats (plankton, artificial collectors and grassbeds) or time. Densities of planktonic megalopae were homogeneous at 1-2 m (within site) but varied at spatial scales of hundreds of meters (between sites) and kilometers (between areas). Settled megalopae were distributed unevenly within and between sites, but their abundance …

A Review Of Introductions Of Exotic Oysters And Biological Planning For New Importations, Jay D. Andrews

VIMS Articles

Importation and transplantation of exotic oysters has probably resulted in the introduction into new areas of more marine invertebrate species than any other of man's activities. Unintentional introductions have resulted from careless movements of oysters without planning or consideration of consequences.

Haplosporidian And Haplosporidian-Like Diseases Of Shellfish, Frank O. Perkins

VIMS Articles

No abstract provided.

Cell Structure Of Shellfish Pathogens And Hyper-Parasites In The Genera Minchinia, Urosporidium, Haplosporidium, And Marteilia - Taxonomic Implications, Frank O. Perkins

VIMS Articles

No abstract provided.

Dermocystidium-Marinum Infection In Oysters, Frank O. Perkins

VIMS Articles

A review of knowledge concerning the life cycle, structure, taxonomy, and pathology of Dermocystidium marinum is presented. The pathogen causes mortalities of the American oyster, Crassostrea virginica, along the Atlantic and Gulf coasts of the United States.

Occurrence Of Hematopoietic Neoplasms In Virginia Oysters (Crassostrea-Virginica), Em Frierman

VIMS Articles

The three predominant pathogens of oysters in Virginia are the haplosporidans Minchinia costalis and M. nelsoni and the protist Dermocystidium marinum (Wood and Andrews, 1962; Haskin, Stauber, and Mackin, 1966; Mackin, Owen, and Collier, 1950).

Oyster Mortality Studies In Virginia. Vii. Review Of Epizootiology And Origin Of Minchinia Nelson, Jay D. Andrews

VIMS Articles

Intensive epizootics in Crassostrea virginica caused by Minchinia nelsoni (MSX) show no signs of abating in lower Chesapeake Bay. Prevalences of the pathogen have commonly exceeded 50% in susceptible stocks during the first year of exposure; mortalities of 50 to 70% occurred during the first year and slightly lower losses in succeeding years. Disease activity increased in isolated lots of oysters from 1963 to 1966 during a drought period with high salinities. Native and planted oysters were extremely scarce in the lower Chesapeake Bay hence density of populations appears not to be important for disease activity. Seasonal patterns of death …

Studies On Oyster Scavengers And Their Relation To The Fungus Dermocystidium Marinum, Hinton Dickson 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 …

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

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, John 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 …

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 as a …

The River Shrimp, Macrobrachium Ohione (Smith), In Virginia, Horton H. Hobbs, William H. Massman

VIMS Articles

The ''river shrimp" belonging to the genus Macrobrachium, which range in length from 34 to more than 230 mm., are not to be confused with the smalier "glass shrimp" belonging to the genus Palaemonetes, at least one species of which is a common form in the waters of the Piedmont and Coastal Plain of Virginia.