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VIMS Articles

2006

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Articles 31 - 41 of 41

Full-Text Articles in Life Sciences

Growth And Maturity Of Salmon Sharks (Lamna Ditropis) In The Eastern And Western North Pacific, And Comments On Back-Calculation Methods, Kenneth J. Goldman, John A. Musick Jan 2006

Growth And Maturity Of Salmon Sharks (Lamna Ditropis) In The Eastern And Western North Pacific, And Comments On Back-Calculation Methods, Kenneth J. Goldman, John A. Musick

VIMS Articles

Age and growth estimates for salmon sharks (Lamna ditropis) in the eastern North Pacific were derived from 182 vertebral centra collected from sharks ranging in length from 62.2 to 213.4 cm precaudal length (PCL) and compared to previously published age and growth data for salmon sharks in the western North Pacific. Eastern North Pacific female and male salmon sharks were aged up to 20 and 17 years, respectively. Relative marginal increment (RMI) analysis showed that postnatal rings form annually between January and March. Von Bertalanffy growth parameters derived from vertebral length-at-age data are L-proportional to=207.4 cm PCL, k=0.17/yr, and t(0)=-2.3 …


Calculating Shoreline Erosion Potential Using Nearshore Stratigraphy And Sediment Volume: Outer Banks, North Carolina, Jennifer L. Miselis, Jesse E. Mcninch Jan 2006

Calculating Shoreline Erosion Potential Using Nearshore Stratigraphy And Sediment Volume: Outer Banks, North Carolina, Jennifer L. Miselis, Jesse E. Mcninch

VIMS Articles

[1] Despite the acknowledged influence of coastal geological framework on the behavior of beaches and barrier islands and a wealth of geological and bathymetric observations from the inner shelf, quantitatively connecting those observations to shoreline behavior has been difficult. Nearshore geologic and morphologic variability described by recent research is not well represented by conventional geologic parameters, such as mean grain size and shoreface slope, used in most shoreline change models. We propose that total nearshore sediment volume, as calculated to a continuous seismic reflection surface, provides a flexible and robust metric for use in the prediction of shoreline change. This …


Influence Of Shallow-Water Habitats And Shoreline Development On Abundance, Biomass, And Diversity Of Benthic Prey And Predators In Chesapeake Bay, Rochelle D. Seitz, Rom Lipcius, N. H. Olmstead, M. S. Seebo Jan 2006

Influence Of Shallow-Water Habitats And Shoreline Development On Abundance, Biomass, And Diversity Of Benthic Prey And Predators In Chesapeake Bay, Rochelle D. Seitz, Rom Lipcius, N. H. Olmstead, M. S. Seebo

VIMS Articles

Within the coastal zone, waterfront development has caused severe loss of shallow-water habitats, such as salt marshes and seagrass beds. Although the effects of habitat degradation on community structure within intertidal marshes have been well studied, little is known about the impact of habitat degradation on, and the ecological value of, subtidal shallow-water habitats, despite the prevalence of these habitats in coastal ecosystems. In coastal habitats, bivalves are dominant benthic organisms that can comprise over 50% of benthic prey biomass and are indicative of benthic production. We quantified bivalve diversity, density, and biomass in deep and shallow (< 1.5 m MLW) unstructured subtidal habitats in 2 tributaries of lower Chesapeake Bay (Elizabeth-Lafayette River system and York River). We also examined the effects of shoreline alteration in shallow habitats by contrasting the benthos of the subtidal areas adjacent to natural marsh, bulkhead, and rip-rap shorelines. Bivalve diversity, density, and biomass were significantly higher in shallow than in deep benthic habitats in both systems. Benthic abundance and diversity were higher in subtidal habitats adjacent to natural marsh than those adjacent to bulkhead shorelines; abundance and diversity were intermediate in rip-rap shorelines, and appeared to depend on landscape features. Predator density and diversity tended to be highest adjacent to natural marsh shorelines, and density of crabs was significantly higher in natural marsh than in bulkhead habitats. There is thus a crucial link between natural marshes, infaunal prey in subtidal habitats, and predator abundance. Consequently, the indirect effects of coastal habitat degradation upon secondary production in the shallow, subtidal habitats adjacent to salt marshes may be as great as or greater than direct habitat effects.


Complications Of A Non-Native Oyster Introduction: Facilitation Of A Local Parasite, Melanie J. Bishop, Ryan Carnegie, Nancy A. Stokes, Charles H. Peterson, Eugene Burreson Jan 2006

Complications Of A Non-Native Oyster Introduction: Facilitation Of A Local Parasite, Melanie J. Bishop, Ryan Carnegie, Nancy A. Stokes, Charles H. Peterson, Eugene Burreson

VIMS Articles

Among the risks of introducing non-native species to novel environments is the possibility that the non-native might serve as a reservoir for enzootic pathogens formerly at low abundance. The recent identification of Bonamia sp. in previously uninfected non-native Suminoe oysters deployed to Bogue Sound, Morehead City, North Carolina, USA, raises serious concerns about the oyster's ability to act as a reservoir for the parasite, not formerly known along the east coast of the USA. To assess the current distribution of the Bonamia sp. parasite and its environmental tolerances, non-reproductive triploid Suminoe oysters, certified as uninfected, were deployed at 5 high …


Assessing Effectiveness Of The Blue Crab Spawning Stock Sanctuary In Chesapeake Bay Using Tag-Return Methodology, Debra M. Lambert, Rom Lipcius, John M. Hoenig Jan 2006

Assessing Effectiveness Of The Blue Crab Spawning Stock Sanctuary In Chesapeake Bay Using Tag-Return Methodology, Debra M. Lambert, Rom Lipcius, John M. Hoenig

VIMS Articles

The blue crab spawning stock in Chesapeake Bay sustained a severe and persistent decline beginning in 1992. As part of the effort to enhance the spawning stock, the spawning sanctuary in lower Chesapeake Bay was enlarged to over 240 000 ha. This marine reserve and corridor prohibits exploitation of mature females en route to or in the spawning grounds during the summer spawning season (1 June to 15 September). To assess the effectiveness of the sanctuary, we tagged terminally melted, mature females inside and outside the sanctuary during 3 sanctuary seasons (2002 to 2004). Crabs were captured throughout the bay …


Plankton Development And Trophic Transfer In Seawater Enclosures With Nutrients And Phaeocystis Pouchetii Added, J. C. Nejstgaard, M. E. Frischer, P. G. Verity, J. T. Anderson, A. Jacobson, Mj Zirbel, A. Larsen, J. Mrtinez-Martinez, Af. Sazhin, T. Walters, Da Bronk, Sj. Whipple, Sr. Borrett, Bc Patten, Jd Long Jan 2006

Plankton Development And Trophic Transfer In Seawater Enclosures With Nutrients And Phaeocystis Pouchetii Added, J. C. Nejstgaard, M. E. Frischer, P. G. Verity, J. T. Anderson, A. Jacobson, Mj Zirbel, A. Larsen, J. Mrtinez-Martinez, Af. Sazhin, T. Walters, Da Bronk, Sj. Whipple, Sr. Borrett, Bc Patten, Jd Long

VIMS Articles

In high latitude planktonic ecosystems where the prymnesiophyte alga Phaeocystis pouchetii is often the dominant primary producer, its importance in structuring planktonic food webs is well known. In this study we investigated how the base of the planktonic food web responds to a P. pouchetii colony bloom in controlled mesocosm systems with natural water enclosed in situ in a West Norwegian fjord. Similar large (11 m(3)) mesocosm studies were conducted in 2 successive years and the dynamics of various components of the planktonic food web from viruses to mesozooplankton investigated. In 2002 (4 to 24 March), 3 mesocosms comprising a …


Biodiversity And The Functioning Of Seagrass Ecosystems, J. Emmett Duffy Jan 2006

Biodiversity And The Functioning Of Seagrass Ecosystems, J. Emmett Duffy

VIMS Articles

Biodiversity at multiple levels - genotypes within species, species within functional groups, habitats within a landscape - enhances productivity, resource use, and stability of seagrass ecosystems. Several themes emerge from a review of the mostly indirect evidence and the few experiments that explicitly manipulated diversity in seagrass systems. First, because many seagrass communities are dominated by 1 or a few plant species, genetic and phenotypic diversity within such foundation species has important influences on ecosystem productivity and stability. Second, in seagrass beds and many other aquatic systems, consumer control is strong, extinction is biased toward large body size and high …


Occurrence Of Imposex And Seasonal Patterns Of Gametogenesis In The Invading Veined Rapa Whelk Rapana Venosa From Chesapeake Bay, Usa, Roger L. Mann, Juliana M. Harding, Erica Westcott Jan 2006

Occurrence Of Imposex And Seasonal Patterns Of Gametogenesis In The Invading Veined Rapa Whelk Rapana Venosa From Chesapeake Bay, Usa, Roger L. Mann, Juliana M. Harding, Erica Westcott

VIMS Articles

The prevalence and intensity of imposex and observations on the seasonal gametogenic cycle are reported for the Asian veined rapa whelk Rapana venosa (Valenciennes, 1846), an invader of the Chesapeake Bay on the North American Atlantic coast. Adult whelks from opportunistic collections by commercial fishermen demonstrated inactivity from mid-November through early March, copulation from February through mid-November, and egg-laying activity from late May through August. All imposex females examined did not have a functional vas deferens (below Stage 3 on the vas deferens scale of Gibbs et al. 1987; J Mar Biol Assoc UK 67:507-523) and were expected to function …


Mesocosm Study Of Particle Dynamics And Control Of Particle-Associated Bacteria By Flagellate Grazing, Kam W. Tang, Hans-Peter Grossart, Emily M. Yam, George A. Jackson Jan 2006

Mesocosm Study Of Particle Dynamics And Control Of Particle-Associated Bacteria By Flagellate Grazing, Kam W. Tang, Hans-Peter Grossart, Emily M. Yam, George A. Jackson

VIMS Articles

The goal of this study was to attain an integrated understanding of the dynamics of attached microbial communities in nature as governed by the component processes of particle formation, colonization, detachment, growth and interspecific interactions among the microbes. The study was conducted in mesocosms in a Danish fjord over a 2 wk period in April to May 2005. Despite nutrient additions, chlorophyll and particle concentrations were low and no distinct phytoplankton blooms were observed. Particle volume concentration was dominated by particles > 100 Pm. The abundance of attached bacteria was weakly but positively correlated with total particle volume. Phylogenetic composition of …


Predation On Posidonia Australis Seeds In Seagrass Habitats Of Rottnest Island, Western Australia: Patterns And Predators, R J. Orth, Gary A. Kendrick, Scott R. Marion Jan 2006

Predation On Posidonia Australis Seeds In Seagrass Habitats Of Rottnest Island, Western Australia: Patterns And Predators, R J. Orth, Gary A. Kendrick, Scott R. Marion

VIMS Articles

Seed predation is an important process governing the dynamics of many plant populations. We assessed seed mortality due to predation in the seagrass Posidonia australis by identifying predators and quantifying predation events using underwater video cameras, laboratory and field observations, and field tethering experiments in shallow-water habitats off Rottnest Island, Western Australia in 2003 (2 sites) and 2004 (5 sites). We assessed 4 dominant habitats: within seagrass meadows of (1) P. australis, (2) Amphibolis antarctica and (3) Halophila ovalis, and on (4) unvegetated sand. Video analysis and field and laboratory observations showed that at least 6 different crustacean taxa were …


Estimating Consumption Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus) In Chesapeake Bay, Virginia, Using A Bioenergetics Model, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick Jan 2006

Estimating Consumption Rates Of Juvenile Sandbar Sharks (Carcharhinus Plumbeus) In Chesapeake Bay, Virginia, Using A Bioenergetics Model, W Wesley Dowd, Richard Brill, Peter Bushnell, John A. Musick

VIMS Articles

Using a bioenergetics model, we estimated daily ration and seasonal prey consumption rates for six age classes of juvenile sandbar sharks (Carcharhinus plumbeus) in the lower Chesapeake Bay summer nursery area. The model, incorporating habitat and species-specific data on growth rates, metabolic rate, diet composition, water temperature (range 16.8-27.9 degrees C), and population structure, predicted mean daily rations between 2.17 +/- 0.03 (age-0) and 1.30 +/- 0.02 (age-5) % body mass/day. These daily rations are higher than earlier predictions for sandbar sharks but are comparable to those for ecologically similar shark species. The total nursery population of sandbar sharks was …