Life Sciences Commons^™

Bivalve Molluscs: Barometers Of Climate Change In Arctic Marine Systems, Roger Mann, Daphne M. Munroe, Eric N. Powell, Eileen E. Hoffmann, John M. Klinck

VIMS Books and Book Chapters

Bivalve mollusks store a complete history of their life in the growth lines in their valves. Through sclerochronology, in combination with isotope signatures, it is possible to reconstruct both post-recruitment growth history at the individual level and commensurate environmental records of temperature and salinity. Growth patterns are integrators of local primary productivity; spatial and temporal changes in growth illustrate commensurate patterns of food availability. Mactrid clams are long-lived, benthic dominant species found on inner continental shelves throughout the Northern Hemisphere where they variously support major fisheries (Spisula solidissima in the Mid-Atlantic Bight, Mactromeris polynyma in eastern Canada, Spisula sachalinensis …

Landscape-Level Impacts Of Shoreline Development On Chesapeake Bay Benthos And Their Predators, Rochelle D. Seitz, Amanda S. Lawless

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Within the coastal zone, waterfront development has caused severe loss of shallow-water habitats such as salt marshes and seagrass beds. Little is known about the impact of habitat degradation and ecological value of subtidal shallow-water habitats, despite their prevalence. In coastal habitats, bivalves are dominant benthic organisms that can comprise over 50% of benthic prey biomass and are indicative of benthic production. We examined the effects of shoreline alteration in shallow habitats by contrasting the benthos of the subtidal areas adjacent to natural marsh, riprap, and bulkhead shorelines in three Chesapeake Bay subestuaries that differ in the level of shoreline …

Constraints On Sustainable Marine Fisheries In The United States: A Look At The Record, John A. Musick, Julia K. Ellis

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The factors that may either constrain or contribute to sustainable marine fisheries were examined by reviewing and analyzing the history and current status of several U.S. fisheries. Among major factors under consideration are inherent vulnerability (vulnerability in some species is high because of low intrinsic rates of increase and/or naturally infrequent recruitment); environmental degradation (fisheries may collapse because of anthropogenic habitat destruction); availability of data (information necessary co conduce accurate stock assessments may be inadequate for some species); quality of the scientific advice (inappropriate models or scientifically inaccurate assessments may be used); and effectiveness of management decisions (managers may disregard …

The Seagrasses Of The Mid-Atlantic Coast Of The United States, E. W. Koch, R. J. Orth

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The mid-Atlantic region of the United States includes four states: Delaware, Maryland, Virginia and North Carolina. It is characterized by numerous estuaries and barrier- island coastal lagoons with expansive salt marshes and seagrass beds in most shallow-water areas. There are no rocky shores . Hard substrates are either man-made [rock jetties and riprap or wood pilings) or biogeniclly generated [oyster and worm reefs). Sediments are predominantly quartz sand in shallow exposed areas with finer grain sediments in deeper or well-protected areas . Marsh peat outcroppings or cohesive sediments are sometimes found in the subtidal areas adjacent to eroding marshes. Climatic …

Sea Turtles, John A. Musick

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Description, keys, habitat and distribution of sea turtles.

Infection And Mortality Studies With Hematodinium Perezi In Blue Crabs, Jeffrey D. Schields

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Blue crabs, Callinectes sapidus, from the Delmarva Peninsula experience recurring epizootics of a pathogenic dinoflag ellate. The parasite, Hematodinium perezi , fulminates in late summer and autumn causing significant mortalities in high salinity embayments and estuaries. Mortality rates during epizootics a re difficult to estimate because dead crabs quickly deteriorate. Host mortality was investigated in naturally- and experimentally-infected crabs. Detection of the parasite, its proliferation in the hemolymph, and distribution in lower Chesapeake Bay were also examined. The dinoflagellate was highly pathogenic, killing 100% of naturally infected crabs, and 86% of inoculated crabs over 35 and 4 0 days, respectively. …

Efficacy Of Blue Crab Spawning Sanctuaries In Chesapeake Bay, Rochelle D. Seitz, Romauld N. Lipcius, William T. Stockhausen, Marcel M. Montane

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Sanctuaries can potentially protect a significant fraction of the spawning stock, and thereby sustain heavily exploited populations. Despite the worldwide use of marine and estuarine spawning sanctuaries, the effectiveness of such sanctuaries remains untested. We therefore attempted to quantify the effectiveness of the spawning sanctuaries for adult female blue crabs (Callinectes sapidus) in Chesapeake Bay. We used baywide winter dredge survey data to estimate the potential spawning stock prior to the major exploitation period, and summer trawl survey data to estimate spawning stock abundance within the Lower Bay Spawning Sanctuary and adjacent Bayside Eastern Shore Sanctuary during the reproductive period. …

A Deepwater Dispersal Corridor For Adult Female Blue Crabs In Chesapeake Bay, Romuald N. Lipcius, Rochelle D. Seitz, William J. Goldsborough, Marcel M. Montane, William T. Stockhausen

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In marine ecosystems, there is no empirical evidence for the utility of dispersal corridors in conservation, despite widespread migrations by mammals, fish, and invertebrates. We investigated the potential for a deepwater dispersal corridor (> 13 m depths) in protecting adult females of the blue crab, Callinectes sapidus, en route from shallow-water nursery and mating areas to the spawning sanctuary in lower Chesapeake Bay.

The Evolution Of The Chesapeake Oyster Reef System During The Holocene Epoch, William J. Hargis Jr.

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The oyster industries of Virginia and Maryland were based upon adult and juvenile oysters, and their shells, produced naturally on the reefs of the Chesapeake oyster reef system. Without those reefs the billions of bushels of live oysters and shells taken by humans could neither have been produced naturally nor harvested and the valuable social and economic activities derived therefrom would never have occurred.

The origin and development of the formerly massive, naturally self-renewing Chesapeake reef system were directly associated with the evolution of the Bay. Its destruction can be linked primarily to the increase of humans around the Bay …

Small-Scale Patterns Of Recruitment On A Constructed Intertidal Reef: The Role Of Spatial Refugia, Ian K. Bartol, Roger Mann

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Traditional oyster repletion activities have utilized a two-dimensional approach to shell (substrate) deployment to attain maximal coverage in subtidal locations with little consideration for optimal thickness of deployed shell and tidal elevation. Vertical dimensionality may play a vital role, however, in the establishment and persistence of oyster communities. Therefore, a three-dimensional oyster reef was constructed in the Piankatank River, Virginia, and settlement and mortality patterns of oysters were recorded from June of 1993 through September of 1994.

Oyster Restoration Efforts In Virginia, James Wesson, Roger L. Mann, Mark Luckenbach

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Long-term restoration of the Virginia Oyster resource has been assisted by a series of governmental and regulatory initiatives. Following the 1990 Blue Ribbon Panel the Virginia Marine Resources Commission set as goals that the oyster resources and oyster fishery would be so managed as to achieve (a) no net loss of existing standing stock of the native oyster over the next five years, and (b) a doubling of the existing standing stock of the native oyster over the next ten years. The 1994 Chesapeake Bay Aquatic Reef Plan and Oyster Fishery Management Plan both recommended the creation of 5,000 acres …

Materials Processing By Oysters In Patches: Interactive Roles Of Current Speed And Seston Composition, Deborah A. Harsh, Mark W. Luckenbach

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Filtration rates for oysters have typically been measure in still water laboratory experiments and ecosystem-level effects estimated by extrapolation. With the exception of in situ measures of oyster filtration by Dame (1999, Chapter 18, this volume and references cited therein) these estimates have failed to account for the effects of hydrodynamic effects on oyster filtration rates and on physical redistribution of particles. In this chapter we report on a series of experiments conducted in a recirculating seawater flume designed to address the effects of flow speed and seston composition on filtration rates in a bed of oysters. In six separate …

Use Of Dredged Material For Oyster Habitat Creation In Coastal Virginia, Walter I. Priest Iii, Janet Neslerode, Christopher W. Frye

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Dredging can have a beneficial effect on oyster habitat when the placement of the dredged material is effectively managed to help provide the bottom structure necessary to develop an oyster reef. Construction and maintenance of the Waterway on the Coast of Virginia (WCV) by the U. S. Army Corps of Engineers (Corps) has provided a number of examples of this process, both serendipitous and deliberate. The historical development of reefs that evolved from the random overboard placement of dredged material and the subsequent leasing of these areas for oyster cultivation is reviewed. A monitoring plan for the development of a …

Chesapeake Oyster Reefs, Their Importance, Destruction And Guidelines For Restoring Them, William J. Hargis Jr., Dexter S. Haven

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The eastern oyster, Crassostrea virginica (Gmelin), can live any place in coastal marine and estuarine waters of the North American east coast offering suitable setting and survival opportunities. It occurs singly or in small clumps scattered widely but thrives best in colonial aggregations which, like those of tropical corals, are truly reefs. The massive self-renewing oyster reefs ("whole banks and beds") reported by early Chesapeake observers have yielded much. Without readily accessible oyster reefs the first English colonists of Jamestown might have starved. Without them the rich oyster industries of later years could never have developed.But oyster reefs benefitted the …

Utilization Of Seagrass Habitat By The Blue Crab, Callinectes Sapidus Rathbun, In Chesapeake Bay: A Review, Robert J. Orth, Jacques Van Montfrans, Romuald N. Lipcius, Karen S. Metcalf

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Seagrasses are generally presumed to provide important habitats for numerous species of vertebrates and invertebrates, serving as a nursery, structure for attachment, or foraging area. However, few species appear directly dependent on seagrass, one notable exception being the bay scallop, Argopecten irradians Lamarck. Research in Chesapeake Bay on the abundant, and commercially exploitable blue crab, Callinectes sapidus Rathbun, over the last decade, focused on the relevance of seagrass habitat for the overall population. Our research has demonstrated: I. higher densities of juvenile blue crabs in seagrass habitats compared to adjacent marsh and unvegetated areas, 2. seagrasses to be an important …

Sediment Characteristics And Inorganic Fluxes Associated With Vegetated And Nonvegetated Subtidal Habitats Of The Goodwin Islands, Virginia, Christopher P. Buzelli

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The Goodwin Islands Ecosystem is a National Estuarine Research Reserve location and consisting of about 200 ha of intertidal mudflat and marshes surrounded by about 600 ha of vegetated and nonvegetated subtidal habitats extending to the -2.0 m depth contour. It is hypothesized that vegetated subtidal and intertidal habitats are seasonal sources of oxygen and fixed carbon and sinks for inorganic nutrients while sediments represent longer- term carbon storage for the ecosystem as a whole. This study focuses upon subtidal sediment microalgal distribution and biomass, sediment organic and inorganic content, and sediment/water oxygen and nutrient exchange processes in vegetated and …

Effects Of A Polyhaline Sav Bed On Spatial And Temporal Variability In Water Quality, Kenneth A. Moore, Jill L. Goodman

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Beds of submerged aquatic vegetation (SAY) may moderate or enhance the standing stocks of dissolved oxygen, nutrients, suspended particulates, and chlorophyll in water masses that are exchanged with adjacent channel areas of the Bay or its tributaries. This study investigated the short-term variability in commonly measured water column parameters at four stations located along a 1 km transect across a polyhaline SAV bed in the lower Bay. Data were collected for 10-day periods during June, August, and October 1993 at 15 min to 3 hr intervals using automated water samplers, arrays of spherical PAR quantum sensors, and Hydrolab datasondes. A …

Trends In Shark Abundance From 1974 To 1991 For The Chesapeake Bight Region Of The U.S. Mid-Atlantic Coast, John A. Musick, Steven Branstetter, James A. Colvocoresses

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Recent stock assessments indicate that the shark stock of the western North Atlantic is exploited at a rate twice the maximum sustainable yield. This finding is supported by data generated by the Virginia Institute of Marine Science longline program for sharks of the. Chesapeake Bay and adjacent coastal waters. Trends in catch per unit of effort since 1974 indicate 60-80% reductions in population size for the common species - sandbar (Carcharhinus plumbeus) , dusky (C. obscurus) , sand tiger (Odontaspis taurus), and tiger (Galeocerdo cuvier) sharks. Declines include numbers of individuals for all species, size classes within species, and in …

Fisheries Assessment And Management Synthesis: Lessons For Chesapeake Bay, William A. Richkus, Steven J. Nelson, Herbert M. Austin

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Describes the basic approaches that are used for stock assessment of the fish and shellfish stocks of the Chesapeake Bay system. The authors summarize the principal methods of stock assessment and fisheries management that have been and are being-applied to Bay fisheries, with particular emphasis on data collection and the use of models. Three case studies of critical species are presented - the striped bass, the blue crab and the Eastern oyster.

Hard Clam Mercenaria Mercenaria, G. Curtis Roegner, Roger L. Mann

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The hard clam is found along the eastern coast of North America from the Gulf of St. Lawrence to Texas. In Chesapeake Bay, the hard clam is restricted to salinities above approximately 12 ppt. An extensive survey of hard clam resources is overdue.

Statements concerning long term trends in populations are not feasible. Hard clams ·grow to a maximum shell length of about 120 mm. There are few documented cases of diseases in wild hard clam populations. Parasitic infestations are also slight. The life cycle of the hard clam includes a pelagic larval phase and a relatively sedentary benthic juvenile …

Hypothetical Northern Spawning Limit And Larval Transport Of Spot, Brenda L. Norcross, Deborah A. Bodolus

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The exact northern limit of the spawning grounds of spot (Leiostomus xanthurus) has not been determined. Previous reports of spot spawning during the winter/spring in the Middle Atlantic Bight (MAB) are refuted based on the presence of low bottom-water temperatures at that time. Analyses of historic bottom isotherms in the MAB during winter/spring show that the most northerly occurrence of required 17° C bottom temperatures from December to May is on the outer continental shelf off North Carolina near the Gulf Stream. It is therefore suggested that spot recruiting to Chesapeake Bay are spawned near Cape Hatteras at the shelf …

Early Life-History Implications Of Selected Carcharhinoid And Lamnoid Sharks Of The Northwest Atlantic, Steven Branstetter

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The size of most newborn sharks makes them susceptible to predation from their own kind and other large fishes. In the northwestern Atlantic, juvenile nursery grounds can be generally classified according to whether or not the young are exposed to such predatory risk. Several related factors-breeding frequency, litter size, size at birth, early growth rate-may help offset early natural mortality. These factors are counterbalanced by the different species in several different ways, producing numerous early life history strategies. In general, slow growing species are either born at relatively large sizes or use protected nursery grounds, whereas faster growing species tend …

Western North Atlantic Shark-Fishery Management Problems And Informational Requirements, Thomas B. Hoff, John A. Musick

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The Mid-Atlantic Fishery Management Council (Council) has primary responsibility for the development ofihe Western North Atlantic Shark Fishery Management Plan (FMP). Currently, there is a consensus among the five East Coast Councils that an FMP for sharks should be prepared. The current concerns focus on many of the same issues that were germane a decade ago when a shark FMP was initiated and then halted mainly because of inadequate information. These issues include 1) an expanded, nondiscriminant, commercial longline fishery ; (2) an existing and rapidly expanding recreational fishery; (3) concern for the extensive waste which occurs from both recreational …

Habitat Use And Population Biology Of Bahamian Spiny Lobster, William F. Herrnkind, Romauld N. Lipcius

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The spiny lobster Panulirus argus is extremely important both for basic scientific research (Davis, 1980) and the seafood industry. Despite the economic significance of Bahamian lobsters, their ecology has been the subject of limited study. Investigators have recorded fishery information (Smith, 1948, 1951), mass migration (Herrnkind and Kanciruk, 1978; Kanciruk and Hermkind, 1978; Hcrmkind, 1980), autumnal reproduction (Kanciruk and Herrnkind, 1976), commercial size composition (Simpson, 1976), life history and ecology of juveniles, and experimental fishing techniques (Waugh and Waugh, 1977; Waugh, 1980). (...) We report here on a 10-month (Sept, 1979-June, 1980) study of Panulirus argus in the region of …

Use Of Immunoassays In Haplosporidan Life Cycle Studies, Eugene M. Burreson

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The development of mitigating measures for the major oyster diseases has been hindered by our poor understanding of the life cycles of the pathogens. Evidence from epidemiological studies and transmission experiments suggests that an intermediate host is present in the life cycle of Haplosporidium species. Immunoassay is a valuable tool for identifying parasite antigen in an intermediate host, and, because of the potential for stage-specific antigens, assays incorporating polyclonal antibodies may be more effective than assays incorporating monoclonal antibodies. Rabbit antibody against purified spores of Haplosporidium costale recognized spores in paraffin sections of oyster tissue , but the antibody did …

Uncertainties And Speculations About The Life Cycle Of The Eastern Oyster Pathogen Haplosporidium Nelsoni (Msx), Harold H. Haskins, Jay D. Andrews

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For 30 years, the pathogen Haplosporidium nelsoni (MSX) has been causing serious mortalities of eastern oysters Crassostrea virginica in the Delaware and Chesapeake bays of the eastern USA. Its life cycle is largely unknown, and methods for control are wanting. Breeding of resistant eastern oyster strains, at this time, offers the best hope for some degree of control of the disease. Although haplosporidians are known by their spores, controlled transmission, with one possible exception, has not been achieved in any of the 30 recognized species. Haplosporidium nelsoni rarely sporulates in eastern oysters, and this and other observations led to early …

Humoral Defense Factors In Marine Bivalves, Fu-Lin E. Chu

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Natural humoral components have been discovered and described in hemolymph from several marine bivalve species including eastern oyster Crassostrea virginica, blue mussel Mitilus edulis, northern quahog Mercenaria mercenaria, softshell Mya arenaria, and Pacific oyster Crassostrea gigas, These hemolymph components are enzymes of lysosomal origin, agglutinins, lectins, hemolysin, and antimicrobial substances, These components are proteins or glycoproteins found in the serum, hemocytes, or both, The exact relationship of these substances to the internal defense of marine bivalves against parasites and pathogenic microorganisms is not known. Lysosomal enzymes seem to have a double role, defense and nutrition. The free- and cell-bound lectins …

Structure Of Protistan Parasites Found In Bivalve Molluscs, Frank O. Perkins

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The literature on the structure of protists parasitizing bivalve molluscs is reviewed, and previously unpublished observations of species of class Perkinsea , phylum Haplosporidia, and class Paramyxea are presented. Descriptions are given of the flagellar apparatus of Perkinsus marinus zoospores, the ultrastructure of Perkinsus sp. from the Baltic macoma Macoma balthica, and the development of haplosporosome-like bodies in Haplosporidium nelsoni. The possible origin of stem cells of Marrteilia sydneyi from the inner two sporoplasms is discussed. New research efforts are suggested which could help elucidate the phylogenetic interrelationships and taxonomic positions of the various taxa and help in efforts to …

Epizootiology Of The Disease Caused By The Oyster Pathogen Perkinsus Marinus And Its Effects On The Oyster Industry, Jay D. Andrews

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Perkinsus marinus is a protozoan parasite that causes a major disease of eastern oysters Crassostrea virginica from Chesapeake Bay south along the Atlantic coast of the USA and throughout the Gulf of Mexico. It is a warm-season disease that kills eastern oysters at temperatures above 20°C. The pathogen requires salinities of at least 12-15%0 to be active, but it persists tenaciously when low temperatures and salinities occur during winter and spring. Prolonged droughts that increase salinities cause extensions of the range of disease. In the Chesapeake Bay, mortalities begin in June and end in October, and up to 50% of …

Submerged Aquatic Vegetation In Delaware's Inland Bays, Robert J. Orth, Kenneth A. Moore

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Submerged aquatic vegetation (SAV) is an important living resource in many coastal areas throughout the world. These plant communities have been cited as some of the most biologically important in the world. ...