Measurements and the Occurrence of Young Sandbar Shark, Carcharhinus milberti, in Chesapeake Bay, Maryland

1960 ◽  
Vol 1 (3/4) ◽  
pp. 204
Author(s):  
Frank J. Schwartz
Keyword(s):  
2020 ◽  
Vol 652 ◽  
pp. 123-136
Author(s):  
DP Crear ◽  
RJ Latour ◽  
MAM Friedrichs ◽  
P St-Laurent ◽  
KC Weng

Nursery area habitats such as estuaries are vital for the success of many fish populations. Climate change is altering conditions in these areas, which can thus impact the availability of suitable nursery habitat. The sandbar shark Carcharhinus plumbeus uses Chesapeake Bay (USA) as a nursery habitat during the summer months from birth up to 10 yr of age. To assess the impacts of climate change on juvenile sandbar sharks, we developed a habitat model using longline data collected from a fishery-independent survey within Chesapeake Bay. With this model, we projected contemporary and future distributions of suitable habitat for juvenile sandbar sharks in Chesapeake Bay under varying environmental regimes. Predicted suitable juvenile sandbar shark habitat was negatively impacted by future increases in temperature, but positively influenced by future decreases in dissolved oxygen. The latter trend was likely related to the habitat partitioning that occurs between different life stages. Changes in salinity had relatively small impacts. By end-of-century the projected amount of suitable bottom habitat decreased; however, when incorporating the entire water column, projected suitable habitat increased. This suggests that juvenile sandbar sharks may need to make a behavioral shift to avoid non-preferred conditions, which could alter their foraging ecology or refuge strategies. As nursery habitats change with climate change, it is crucial to understand how a species may be impacted during this vital life stage when trying to predict overall species success in the future.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniel P Crear ◽  
Rich W Brill ◽  
Peter G Bushnell ◽  
Robert J Latour ◽  
Gail D Schwieterman ◽  
...  

Abstract Climate change is causing the warming and deoxygenation of coastal habitats like Chesapeake Bay that serve as important nursery habitats for many marine fish species. As conditions continue to change, it is important to understand how these changes impact individual species’ behavioral and metabolic performance. The sandbar shark (Carcharhinus plumbeus) is an obligate ram-ventilating apex predator whose juveniles use Chesapeake Bay as a nursery ground up to 10 years of age. The objective of this study was to measure juvenile sandbar shark metabolic and behavioral performance as a proxy for overall performance (i.e. fitness or success) when exposed to warm and hypoxic water. Juvenile sandbar sharks (79.5–113.5 cm total length) were collected from an estuary along the eastern shore of Virginia and returned to lab where they were fitted with an accelerometer, placed in a respirometer and exposed to varying temperatures and oxygen levels. Juvenile sandbar shark overall performance declined substantially at 32°C or when dissolved oxygen concentration was reduced below 3.5 mg l−1 (51% oxygen saturation between 24–32°C). As the extent of warm hypoxic water increases in Chesapeake Bay, we expect that the available sandbar shark nursery habitat will be reduced, which may negatively impact the population of sandbar sharks in the western Atlantic as well as the overall health of the ecosystem within Chesapeake Bay.


Itinerario ◽  
2000 ◽  
Vol 24 (2) ◽  
pp. 146-169 ◽  
Author(s):  
Michael Leroy Oberg

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.


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

2020 ◽  
Vol 651 ◽  
pp. 125-143
Author(s):  
TD Auth ◽  
T Arula ◽  
ED Houde ◽  
RJ Woodland

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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