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Full-Text Articles in Aquaculture and Fisheries
Effects Of Hypoxia And Anoxia On Survival, Energy Metabolism, And Feeding Of Oyster Larvae (Crassostrea Virginica, Gmelin), J Widdows, Rie Newell, Roger L. Mann
Effects Of Hypoxia And Anoxia On Survival, Energy Metabolism, And Feeding Of Oyster Larvae (Crassostrea Virginica, Gmelin), J Widdows, Rie Newell, Roger L. Mann
VIMS Articles
The tolerance of Crassostrea virginica larvae to anoxia increases with developmental stage and body size. Median mortality times range from 11 h for prodissoconch larvae of 82 micro m (shell length) to 51 h for pediveliger larvae of 3 12 micro m, and 150 h for juvenile oysters. Simultaneous calorimetry and respirometry showed that in response to declining oxygen tension (P02), the rates of heat dissipation and oxygen uptake by oyster larvae are maintained independent of PO2 down to low Pc values (2 kPa for prodissoconch larvae and 8 kPa for pediveliger and juveniles). Therefore, total energy metabolism is sustained …
Commercial Practices And Fishery Regulations. The United States Northwest Atlantic Sea Scallop, Placopecten Magellanicus (Gmelin, 1791), Fishery, James E. Kirkley, William D. Dupaul
Commercial Practices And Fishery Regulations. The United States Northwest Atlantic Sea Scallop, Placopecten Magellanicus (Gmelin, 1791), Fishery, James E. Kirkley, William D. Dupaul
VIMS Articles
Fishery regulations are based on discipline specific concepts, empirical analyses, and public comment. Supporting empirical analyses, however, often neglect commercial fishing practices. If supporting analyses do not adequately consider commercial practices, resultant regulations may fail to achieve stated objectives and impose unnecessary costs on industry. This may have been the case for the United States Atlantic sea scallop, Placopecten magellanicus, fishery in which empirical analyses determined a target specification of 30 meats per pound, as a maximum average value, would provide significant long-term benefits in terms of yield per recruit and the overall productivity of the resource. Targeted meat count …
Anatomical Features In Histological Sections Of Crassostrea Virginica (Gmelin, 1791) As An Aid In Management Of Gonad Area For Reproductive Assessment, Reinaldo Morales-Alamo, Roger L. Mann
Anatomical Features In Histological Sections Of Crassostrea Virginica (Gmelin, 1791) As An Aid In Management Of Gonad Area For Reproductive Assessment, Reinaldo Morales-Alamo, Roger L. Mann
VIMS Articles
The relationship between gonad area in transverse histological sections of the American oyster Crassostrea virginica (Gmelin 1790) and body location from which the section was cut was studied in specimens collected from four stations in the James River, Virginia in 1984 and 1986. Gonad area, expressed as percentage of total body area, increases in an antero-posterior direction; this requires use of sections from the same body location in comparisons between oysters. Approximate body locations, identified according to the anatomy and arrangement of the internal organs in the sections, were grouped into five types with similar gonad area percentages. One of …
The Location And Topography Of Oyster Reefs In The Rappahannock River Estuary, Virginia., James P. Whitcomb, Dexter S. Haven
The Location And Topography Of Oyster Reefs In The Rappahannock River Estuary, Virginia., James P. Whitcomb, Dexter S. Haven
VIMS Articles
Public oyster grounds in the Rappahannock River, Virginia were charted in 1976 and 1977 using an electronic positioning system to locate oysters, shell, sand, or mud. Hydraulically operated patent tongs were used to sample the bottoms to validate the charts. During this study 17277.6 ha of public bottoms were surveyed; of this total, 3845.3 ha was oyster reef, sand-shell or mud-shell bottoms; the remainder, 13432.3 ha (78%) was sand, mud or buried shell. The location, extent, topography and environment of the oyster producing areas are discussed. Setting of oysters, physiography and productivity were analyzed.
Biological Control Of Crab Predation On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758) By The Toadfish Opsanus Tau (Linnaeus) In Tray Cultures, Robert Bisker, Michael Castagna
Biological Control Of Crab Predation On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758) By The Toadfish Opsanus Tau (Linnaeus) In Tray Cultures, Robert Bisker, Michael Castagna
VIMS Articles
Oyster toadfish Opsanus tau (Linne) were tested as biological controls of crab predation on juvenile hard clams Mercenaria mercenaria (Linne) in trays with crushed stone aggregate. Clam survival after 34 weeks was 69.5% in the presence of toadfish and 2.3% in trays without toadfish. Toadfish reduced the total number of crabs (mud crabs and blue crabs). Crabs in trays with toadfish present had smaller carapace widths.
Predation By The Oyster Toadfish Opsanus Tau (Linnaeus) On Blue Crabs And Mud Crabs, Predators Of The Hard Clam Mercenaria Mercenaria (Linnaeus, 1758), Robert Bisker, Mary Gibbons, Michael Castagna
Predation By The Oyster Toadfish Opsanus Tau (Linnaeus) On Blue Crabs And Mud Crabs, Predators Of The Hard Clam Mercenaria Mercenaria (Linnaeus, 1758), Robert Bisker, Mary Gibbons, Michael Castagna
VIMS Articles
The oyster toadfish, Opsanus tau (Linne), reduces predation by xanthid and portunid crabs on juvenile hard clams, Mercenaria mercenaria (Linne), in field cultures. This study examined the influence of size and species on the predator-prey relationship between toadfish and crabs. The mud crabs Eurypanopeus depressus (Smith), Neopanope sayi (Smith), and Panopeus herbstii Milne Edwards of 5-40 mm carapace width and blue crabs Callinectes sapidus Rathbun of 77-105 mm carapace width were offered to toadfish of 70-322 mm total length. Toadfish predation rates on mud crabs were higher with increasing toadfish size and lower with increasing crab size. Toadfish injured or …
Shell And Pallet Morphology In Early Developmental Stages Of Teredo Navalis Linne (Bivalvia : Teredinidae), S. Cynthia Fuller, Ya-Ping Hu, Richard Lutz, Michael Castagna
Shell And Pallet Morphology In Early Developmental Stages Of Teredo Navalis Linne (Bivalvia : Teredinidae), S. Cynthia Fuller, Ya-Ping Hu, Richard Lutz, Michael Castagna
VIMS Articles
Dimensions of the shell and provinculum distinguish Teredo novalis larvae from the larvae o[ other bivalve mollusks. In the present scanning electron microscopic stud) of shell and pallet morphology during early ontogenetic stages of this species, the characteristic teredinid provinculum, with two interlocking pairs of small teeth and a wide central loath and socket was well-developed in shells 90 μm long. Provinculurn length ranged from 44 to 51 μm during the larval period. Average lengths of provincular teeth of the left valve were 9.6 μm for the anterior tooth and 8.2 μm for the posterior tooth; in the right valve, …