Size-structured patterns of piscivory of the longfin inshore squid (Loligo pealeii) in the mid-Atlantic continental shelf ecosystem

2006 ◽  
Vol 63 (4) ◽  
pp. 754-765 ◽  
Author(s):  
Mary E Hunsicker ◽  
Timothy E Essington
Keyword(s):  
Continental Shelf ◽  
Time Period ◽  
Size Constraints ◽  
Body Sizes ◽  
The Usa ◽  
Juvenile Stages ◽  
Commercially Important ◽  
Shelf Region ◽  
Loligo Pealeii

The longfin inshore squid (Loligo pealeii) dominates the landings in the USA mid-Atlantic continental shelf region, yet the potential ecological effects of harvesting this species are not known. Because squid feed on a wide variety of prey items, including juvenile stages of commercially important fish species, a full exploration on the predatory role of squid in this ecosystem is warranted. We examined the seasonal diet contents of L. pealeii and evaluated the importance of size constraints in governing patterns of piscivory. Our analyses showed that piscivory was dictated by size constraints, with larger squid demonstrating higher rates of piscivory than small squid. Squid were piscivorous at smaller sizes in the winter and spring than during the summer and autumn. Also, the frequency of piscivory was highest during the winter and spring, coincident with the time period when the number of vulnerable prey species was greatest. Our findings suggest that the frequency and intensity of piscivory are likely to be related to the duration of time that prey are vulnerable to predation, which in turn is dictated by the relative body sizes of L. pealeii and juvenile fishes.

scholarly journals The role of continental shelves in nitrogen and carbon cycling

2010 ◽  
Vol 7 (1) ◽  
pp. 177-205
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region ◽  
Transformation Processes

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in observation-based estimates of nitrogen and carbon fluxes mostly result from uncertainties in the shelf-open ocean exchange of organic and inorganic matter, which is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

scholarly journals The role of continental shelves in nitrogen and carbon cycling: Northwestern North Atlantic case study

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 539-548 ◽  
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in the magnitude of organic and inorganic matter exchange between shelves and the open ocean is a major source of uncertainty in observation-based estimates of nitrogen and carbon fluxes. The shelf-open ocean exchange is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

Evaluating the potential for trophodynamic control of fish by the longfin inshore squid (Loligo pealeii) in the Northwest Atlantic Ocean

2008 ◽  
Vol 65 (11) ◽  
pp. 2524-2535 ◽  
Author(s):  
Mary E. Hunsicker ◽  
Timothy E. Essington
Keyword(s):  
Published Data ◽  
Apex Predator ◽  
Northwest Atlantic ◽  
Fish Stocks ◽  
Juvenile Mortality ◽  
Fish Recruitment ◽  
Juvenile Stages ◽  
Commercially Important ◽  
A Minor ◽  
Loligo Pealeii

Many marine apex predator populations have been depleted via targeted fishing, potentially enhancing the productivity of lower trophic-level species such as squid. Squid may be predators of juvenile stages of fish stocks, so fishing could induce depensatory juvenile mortality. Here we evaluate the energetic potential of the longfin inshore squid ( Loligo pealeii ) to exert trophodynamic control on recruitment of several commercially important fish populations. We estimated the population prey consumption of L. pealeii by developing bioenergetics and population models based on previously published data. Our predictions of population consumption showed that squid consume high quantities of prey on daily and seasonal time scales. Further, comparisons between our estimates of population consumption and fish recruitment biomass indicate that L. pealeii may potentially exert a trophodynamic control on the recruitment success of commercially exploited fish species even if these species are only a minor prey item of squid. Overall, our findings suggest that the predation interactions of L. pealeii should be considered when managing and rebuilding fish stocks in the northwest Atlantic continental shelf ecosystem.

Effects of cumulative language exposure on heritage and majority language skills

2019 ◽  
Author(s):  
Lily Tao ◽  
Qing Cai ◽  
Tamar H. Gollan
Keyword(s):  
Early Adulthood ◽  
Cumulative Exposure ◽  
Language Performance ◽  
Language Groups ◽  
Time Period ◽  
The Usa ◽  
Parental Input ◽  
Time Periods ◽  
Different Sources

This study investigated the effects of the amount of cumulative heritage language (HL) exposure during three time periods, on heritage and majority language performance in young adulthood, among two distinct groups of immigrant populations in the USA. Within each time period, exposure from three different sources were examined, and amount of cumulative exposure was calculated encompassing exposure from preceding periods. Factors that may modulate exposure effects were also assessed. Results showed that greater cumulative HL exposure from people at home during all three time periods significantly predicted HL skills for both language groups. For effects on English skills, only the Spanish group showed any influences of exposure. These effects were modulated by parental English proficiency. Input from other sources had less impact. The present findings support the role of parental input throughout childhood, adolescence, and early adulthood in improving HL skills, with less noticeable consequences for the majority language.

The ambivalent role of the institution in the history of child and adolescent psychiatry: a case study of the Hawthorn Centre in Michigan, USA

2020 ◽  
Vol 31 (4) ◽  
pp. 440-454
Author(s):  
Robert Cesaro ◽  
Laura Hirshbein
Keyword(s):  
Psychiatric Care ◽  
Child And Adolescent Psychiatry ◽  
Economic Factors ◽  
Psychiatric Institutions ◽  
Time Period ◽  
The Usa ◽  
History Of ◽  
Different Characteristics

Historians have examined the role of psychiatric institutions in the USA and addressed whether this form of care helped or harmed patients (depending on the perspective of the time period, historical actors, and historians). But the story for children’s mental institutions was different. At the time when adult institutions were in decline, children’s mental hospitals were expanding. Parents and advocates clamoured for more beds and more services. The decrease in facilities for children was more due to economic factors than ideological opposition. This paper explores a case study of a hospital in Michigan as a window into the different characteristics of the discussion of psychiatric care for children.

Public decisions on animal species: does body size matter?

2010 ◽  
Vol 38 (1) ◽  
pp. 28-36 ◽  
Author(s):  
EDO KNEGTERING ◽  
HENNY J. VAN DER WINDT ◽  
ANTON J. M. SCHOOT UITERKAMP
Keyword(s):  
Body Size ◽  
Animal Species ◽  
Factors Affecting ◽  
Time Period ◽  
Body Sizes ◽  
Mollusc Species ◽  
Species Specific ◽  
Size Matter ◽  
Average Body

SUMMARYSystematic knowledge about factors affecting the willingness of societies to conserve biodiversity is still scarce. This study investigates the role of body size in national decisions on wild animal species by analysing the average body sizes of the animal species subject to species-specific legislation in the Netherlands over the period 1857–1995. Three legal objectives were distinguished, namely ‘control’, ‘use’ and ‘protection’. For most taxa, average body sizes of species were found to differ significantly between legal objectives within a substantial number of subperiods analysed. Throughout the entire period examined, protected bird, mammal, fish and mollusc species were of smaller average body size than those subject to use legislation and protected bird, mammal and mollusc species were also smaller than those subject to control legislation most of the time. Protected insects were generally larger than those subject to control or use. For vertebrate taxa, average sizes of protected species increased over the time period selected for examination, suggesting that legislation initially excluded larger vertebrates from protection, possibly partly owing to demands to maintain use of these species. The results emphasize that conservation context is important, as other studies suggest that conservation policy generally favours larger species.

EPIZOOTOLOGICAL FEATURES OF MODERN CATTLE LEUKEMIA

1970 ◽  
pp. 53-58
Author(s):  
V. V. Makarov ◽  
D. A. Lozovoy
Keyword(s):  
Dairy Cattle ◽  
Western Europe ◽  
Control Programs ◽  
Foreign Countries ◽  
Negative Order ◽  
Dairy Cattle Breeding ◽  
The Usa ◽  
Epizootic Process ◽  
National Programs

  Enzootic bovine leucosis (EBL) has been known for more than a century and a half. Its occurrence and registration may have historically been associated with intensive breeding of dairy cattle in Western Europe to increase target productivity. It is known that any limiting intervention in the nature of the animal organism is always accompanied by an uncontrolled and unpredictable change in the genotype of a wider range than the required, particularly negative order. In particular, a decrease in the resistance to macroorganisms and the possibility of the new diseases emergence, including infectious ones (for example, immunodeficiencies such as BLAD syndrome of black-motley cattle and stress syndrome in pigs, the occurrence of scrapie and other slow sheep infections). In the last two decades of the last century, in many disadvantaged countries, primarily Western European, national programs for the eradication of EBL have been developed and subsequently successfully implemented. First of all the motivation was the economy of dairy cattle breeding (mainly the extension of productive age, as well as the tightening of requirements in international trade in cattle and bull products, breeding, pricing, etc.). In an analytical article are reviewed the elements of epizootology of EBL in the foreign countries with special attention to the situation in the USA, scenarios of various control programs, and promising methods for assessing the role of infected animals in the epizootic process. A critical assessment of the problem of EBL in the Russian Federation is given, the reasons for the ineffectiveness of against leucosis measures are discussed.

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