Influence of Winter Conditions on the Age, Hatch Dates, and Growth of Juvenile Atlantic Menhaden in the Choptank River, Maryland

2017 ◽  
Vol 146 (6) ◽  
pp. 1126-1136 ◽  
Author(s):  
Alexandra N. Atkinson ◽  
David H. Secor
Keyword(s):  
Atlantic Menhaden ◽  
Winter Conditions ◽  
Choptank River

Utilizing next-generation sequencing to identify prey DNA in western North Atlantic grey seal Halichoerus grypus diet

2020 ◽  
Vol 655 ◽  
pp. 227-240
Author(s):  
KR Flanders ◽  
ZH Olson ◽  
KA Ono
Keyword(s):  
Next Generation Sequencing ◽  
Feeding Habits ◽  
Atlantic Menhaden ◽  
Halichoerus Grypus ◽  
Frequency Of Occurrence ◽  
Grey Seal ◽  
Next Generation ◽  
Significant Difference ◽  
Generation Sequencing ◽  
Seal Diet

Increasing grey seal Halichoerus grypus abundance in coastal New England is leading to social, political, economic, and ecological controversies. Central to these issues is the foraging ecology and diet composition of the seals. We studied grey seal feeding habits through next-generation sequencing of prey DNA using 16S amplicons from seal scat (n = 74) collected from a breeding colony on Monomoy Island in Massachusetts, USA, and report frequency of occurrence and relative read abundance. We also assigned seal sex to scat samples using a revised PCR assay. In contrast to current understanding of grey seal diet from hard parts and fatty acid analysis, we found no significant difference between male and female diet measured by alpha and beta diversity. Overall, we detected 24 prey groups, 18 of which resolved to species. Sand lance Ammodytes spp. were the most frequently consumed prey group, with a frequency of occurrence (FO) of 97.3%, consistent with previous studies, but Atlantic menhaden Brevoortia tyrannus, the second most frequently consumed species (FO = 60.8%), has not previously been documented in US grey seal diet. Our results suggest that a metabarcoding approach to seal food habits can yield important new ecological insights, but that traditional hard parts analysis does not underestimate consumption of Atlantic cod Gadus morhua (FO = 6.7%, Gadidae spp.) and salmon Salmo salar (FO = 0%), 2 particularly valuable species of concern.

MEASURE COMPLEX SUPPORTING SAFETY AND EFFECTUVE OPERATION OF MUNICIPAL BUSES UNDER WINTER CONDITIONS

2020 ◽  
Vol 2020 (10) ◽  
pp. 37-41
Author(s):  
Sergey Bulatov
Keyword(s):  
Residual Life ◽  
Technical State ◽  
Manufacturing Equipment ◽  
Winter Conditions ◽  
On Line ◽  
State Changes ◽  
The City

The effectiveness of manufacturing equipment use taking into account its productivity and reliability for faulty parts of transmission units in municipal buses is estimated. The on-line mode is the most effective method of control allowing the tracking of the processes of technical state changes in municipal buses. As a result of monitoring there were obtained selected data on PAZ-3205 municipal bus operated under winter conditions in the city of Ohrenburg. During the trip there was recorded 39.1 l/100km petrol consumption. The residual life of the PAZ-3205 municipal bus was 1800km.

Archive of Chirp subbottom data collected during USGS Cruise RAFA01025, Choptank River, Maryland, March 6-9, 2001

2003 ◽  
Author(s):  
B. Ann Swift ◽  
E.R. Thieler ◽  
Steven M. Colman ◽  
D.R. Nichols
Keyword(s):  
Choptank River

Archive of Boomer subbottom data collected during USGS Cruise RAFA01025, Choptank River, Maryland, March 6-9, 2001

2003 ◽  
Author(s):  
B. Ann Swift ◽  
E.R. Thieler ◽  
Steven M. Colman ◽  
D.R. Nichols
Keyword(s):  
Choptank River

Obtaining Secondary Treatment with RBC/Underflow Clarifiers

1982 ◽  
Vol 14 (6-7) ◽  
pp. 429-442
Author(s):  
I L Bogert
Keyword(s):  
Treatment Process ◽  
High Rate ◽  
Experimental Program ◽  
Secondary Treatment ◽  
Lower Zone ◽  
Treatment Efficiency ◽  
Winter Conditions ◽  
Rotating Biological Contactors ◽  
One Year ◽  
The U.S

A one-year experimental program conducted at Edgewater, New Jersey, U.S.A. evaluated the concept of providing secondary treatment by the installation of rotating biological contactors (RBC's) in modified primary sedimentation tanks. A primary tank was divided horizontally into two zones separated by an intermediate floor. Four RBC's were placed in the upper zone. The lower zone provided secondary sedimentation. High rate primary sedimentation was provided to remove grit and trash without removing substantial portions of BOD and SS. The experimental program funded by the U.S. EPA and the Borough of Edgewater was conducted over a full year at different loads. The system proved to be an effective secondary treatment process with little difference in treatment efficiency between summer and winter conditions.

An ecological study of the branchiobdellid commensals (Annelida-Branchiobdellidae) of some mid-western Ontario crayfish

1968 ◽  
Vol 46 (5) ◽  
pp. 835-843 ◽  
Author(s):  
John E. Bishop
Keyword(s):  
Host Specificity ◽  
Dominant Species ◽  
Ecological Study ◽  
Rabbit Serum ◽  
First Year ◽  
Serological Testing ◽  
Severe Winter ◽  
Orconectes Propinquus ◽  
Winter Conditions ◽  
Laurel Creek

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

scholarly journals Shorter, warmer winters may inhibit production of ephyrae in a population of the moon jellyfish Aurelia aurita

Hydrobiologia ◽  
2020 ◽  
Author(s):  
Alexandra Loveridge ◽  
Cathy H. Lucas ◽  
Kylie A. Pitt
Keyword(s):  
Incubation Time ◽  
Life Stage ◽  
Aurelia Aurita ◽  
The Moon ◽  
Minimum Period ◽  
Moon Jellyfish ◽  
Winter Conditions ◽  
Scyphozoan Jellyfish ◽  
Significant Production ◽  
Planula Larvae

AbstractScyphozoan jellyfish blooms display high interannual variability in terms of timing of appearance and size of the bloom. To understand the causes of this variability, the conditions experienced by the polyps prior to the production of ephyrae in the spring were examined. Polyps reared from planula larvae of Aurelia aurita medusae collected from southern England (50°49′58.8; − 1°05′36.9) were incubated under orthogonal combinations of temperature (4, 7, 10 °C) and duration (2, 4, 6, 8 weeks), representing the range of winter conditions in that region, before experiencing an increase to 13 °C. Timing and success of strobilation were recorded. No significant production of ephyrae was observed in any of the 2- and 4-week incubations, or in any 10 °C incubation. Time to first ephyra release decreased with longer winter incubations, and more ephyrae were produced following longer and colder winter simulations. This experiment indicates that A. aurita requires a minimum period of cooler temperatures to strobilate, and contradicts claims that jellyfish populations will be more prevalent in warming oceans, specifically in the context of warmer winter conditions. Such investigations on population-specific ontogeny highlights the need to examine each life stage separately as well as in the context of its environment.

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