Oyster Shell Production and Loss in the Chesapeake Bay

2022 ◽  
Vol 40 (3) ◽  
Author(s):  
Roger Mann ◽  
Melissa Southworth ◽  
James Wesson ◽  
John Thomas ◽  
Mitchell Tarnowski ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
Oyster Shell ◽  
Shell Production

scholarly journals A conservation palaeobiological perspective on Chesapeake Bay oysters

2019 ◽  
Vol 374 (1788) ◽  
pp. 20190209 ◽  
Author(s):  
Rowan Lockwood ◽  
Roger Mann
Keyword(s):  
Chesapeake Bay ◽  
Fossil Record ◽  
Ecosystem Engineer ◽  
Oyster Shell ◽  
Eastern Oyster ◽  
Vital Role ◽  
The Past ◽  
Region Data ◽  
Order Of Magnitude ◽  
Fossil Data

The eastern oyster plays a vital role in estuarine habitats, acting as an ecosystem engineer and improving water quality. Populations of Chesapeake Bay oysters have declined precipitously in recent decades. The fossil record, which preserves 500 000 years of once-thriving reefs, provides a unique opportunity to study pristine reefs to establish a possible baseline for mitigation. For this study, over 900 fossil oysters were examined from three Pleistocene localities in the Chesapeake region. Data on oyster shell lengths, lifespans and population density were assessed. Comparisons to modern Crassostrea virginica , sampled from monitoring surveys of similar environments, reveal that fossil oysters were significantly larger, longer-lived and more abundant than modern oysters from polyhaline salinity zones. This pattern results from the preferential harvesting of larger, reproductively more active females from the modern population. These fossil data, combined with modern estimates of age-based fecundity and mortality, make it possible to estimate ecosystem services in these long-dead reefs, including filtering capacity, which was an order of magnitude greater in the past than today. Conservation palaeobiology can provide us with a picture of not just what the Chesapeake Bay looked like, but how it functioned, before humans. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

scholarly journals Habitat complexity and benthic predator-prey interactions in Chesapeake Bay

2017 ◽  
Author(s):  
Cassandra N. Glaspie ◽  
Rochelle D. Seitz
Keyword(s):  
Chesapeake Bay ◽  
Habitat Complexity ◽  
Age Distribution ◽  
Oyster Shell ◽  
Mercenaria Mercenaria ◽  
Mya Arenaria ◽  
Hard Clam ◽  
Population Declines ◽  
Predator Prey ◽  
Mesocosm Experiments

ABSTRACTIn Chesapeake Bay, the soft-shell clam Mya arenaria (thin-shelled, deep-burrowing) exhibits population declines when predators are active and persists at low densities. In contrast, the hard clam Mercenaria mercenaria (thick-shelled, shallow-burrowing) has a stable population and age distribution. We examined the potential for habitat and predators to control densities and distributions of bivalves in a field caging experiment (Mya only) and laboratory mesocosm experiments (both species). In the field, clams exposed to predators experienced 76.3% greater mortality as compared to caged individuals, and blue crabs were likely responsible for most of the mortality of juvenile Mya. In mesocosm experiments, Mya had lower survival in sand and seagrass than in shell hash or oyster shell habitats. However, crabs often missed one or more prey in seagrass, shell, and oyster shell habitats. Predator search times and encounter rates declined when prey were at low densities, likely due to the added cost of inefficient foraging; however, this effect was more pronounced for Mya than for Mercenaria. Mercenaria had higher survival than Mya in mesocosm experiments, likely because predators feeding on Mercenaria spent less time foraging than those feeding on Mya. Mya may retain a low-density refuge from predation even with the loss of structurally complex habitats, though a loss of habitat refuge may result in clam densities that are not sustainable. A better understanding of density-dependent predator-prey interactions is necessary to prevent loss of food-web integrity and to conserve marine resources.

Between ‘Savage Man’ and ‘Most Faithful Englishman’ Manteo and the Early Anglo-Indian Exchange, 1584–1590

Itinerario ◽  
2000 ◽  
Vol 24 (2) ◽  
pp. 146-169 ◽  
Author(s):  
Michael Leroy Oberg
Keyword(s):  
North Carolina ◽  
Chesapeake Bay ◽  
One Year ◽  
Anglo Indian

In August of 1587 Manteo, an Indian from Croatoan Island, joined a group of English settlers in an attack on the native village of Dasemunkepeuc, located on the coast of present-day North Carolina. These colonists, amongst whom Manteo lived, had landed on Roanoke Island less than a month before, dumped there by a pilot more interested in hunting Spanish prize ships than in carrying colonists to their intended place of settlement along the Chesapeake Bay. The colonists had hoped to re-establish peaceful relations with area natives, and for that reason they relied upon Manteo to act as an interpreter, broker, and intercultural diplomat. The legacy of Anglo-Indian bitterness remaining from Ralph Lane's military settlement, however, which had hastily abandoned the island one year before, was too great for Manteo to overcome. The settlers found themselves that summer in the midst of hostile Indians.

Developing TMDLs for Local Impairments Consistent with the Regional Chesapeake Bay TMDL

2012 ◽  
Author(s):  
Gene Yagow ◽  
Brian Benham ◽  
Karen Kline ◽  
Becky Zeckoski ◽  
Carlington Wallace
Keyword(s):  
Chesapeake Bay

Spatial ecology and growth in early life stages of bay anchovy Anchoa mitchilli in Chesapeake Bay (USA)

2020 ◽  
Vol 651 ◽  
pp. 125-143
Author(s):  
TD Auth ◽  
T Arula ◽  
ED Houde ◽  
RJ Woodland
Keyword(s):  
Chesapeake Bay ◽  
Spatial Ecology ◽  
Environmental Variability ◽  
Larval Growth ◽  
Larval Abundance ◽  
Spatial And Temporal Variability ◽  
Estuarine Ecosystem ◽  
Anchoa Mitchilli ◽  
Larval Production ◽  
Bay Anchovy

The bay anchovy Anchoa mitchilli is the most abundant fish in Chesapeake Bay (USA) and is a vital link between plankton and piscivores within the trophic structure of this large estuarine ecosystem. Baywide distributions and abundances of bay anchovy eggs and larvae, and larval growth, were analyzed in a 5 yr program to evaluate temporal and spatial variability based on research surveys in the 1995-1999 spawning seasons. Effects of environmental variability and abundance of zooplankton that serve as prey for larval bay anchovy were analyzed. In the years of these surveys, 97.6% of eggs and 98.8% of larvae occurred in the polyhaline lower bay. Median egg and larval abundances differed more than 10-fold for surveys conducted in the 5 yr and were highest in the lower bay. Within years, median larval abundance (ind. m-2) in the lower bay was generally 1-2 orders of magnitude higher than upper-bay abundance. Salinity, temperature, and dissolved oxygen explained 12% of the spatial and temporal variability in egg abundances and accounted for 27% of the variability in larval abundances. The mean, baywide growth rate for larvae over the 5 yr period was 0.75 ± 0.01 mm d-1, and was best explained by zooplankton concentration and feeding incidence. Among years, mean growth rates ranged from 0.68 (in 1999) to 0.81 (in 1998) mm d-1 and were fastest in the upper bay. We identified environmental factors, especially salinity, that contributed to broadscale variability in egg and larval production.

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