Performance variability of matched‐field processors on a shelf‐break region in the Mid‐Atlantic Bight

2005 ◽  
Vol 118 (3) ◽  
pp. 2002-2003
Author(s):  
Young‐Nam Na ◽  
Peter C. Mignerey ◽  
Bruce H. Pasewark
Keyword(s):  
Shelf Break ◽  
Performance Variability ◽  
Break Region

Temporal and spatial patterns of spawning in jack mackerel, Trachurus declivis (Pisces:Carangidae), during 1988-91 in eastern Tasmanian waters

1995 ◽  
Vol 46 (5) ◽  
pp. 831 ◽  
Author(s):  
A Jordan ◽  
G Pullen ◽  
J Marshall ◽  
H Williams
Keyword(s):  
Thermal Structure ◽  
Shelf Break ◽  
Eastern Coast ◽  
Jack Mackerel ◽  
Spatial And Temporal Patterns ◽  
Cold Event ◽  
Temporal And Spatial ◽  
High Concentrations ◽  
Break Region ◽  
Eggs And Larvae

Ichthyoplankton surveys conducted during the summer and autumn of 1988-89, 1989-90 and 1990-91 along the eastern coast of Tasmania were used to examine the spatial and temporal patterns of eggs and larvae of jack mackerel, Trachurus declivis. Results indicate that the species spawns along the entire eastern coast during summer. Trachurus declivis eggs were most abundant at shelf-break stations, indicating that spawning is concentrated in this region, although high concentrations of eggs were present on the inner shelf in 1988-89, which can be attributed to rapid onshore transport in that year. Larvae were evenly dispersed over the shelf, with the distribution of larval ages showing no indication of inshore recruitment. Considerable interannual differences in sea surface temperatures and vertical thermal structure were apparent, with the warmer waters and strong thermal stratification in the summer of 1988-89 resulting from the influx of subtropical East Australian Current (EAC) water onto the shelf, which corresponded with a major La Nina 'cold event' at that time. It is suggested that the distribution of spawning is unaffected by the interannual variations in oceanography as the mature population spawns in deeper water in the shelf-break region that is unaffected by the warming in surface waters.

Metamorphosis of the final phyllosoma and secondary lecithotrophy in the puerulus of Panulirus cygnus George: a review

1997 ◽  
Vol 48 (8) ◽  
pp. 783 ◽  
Author(s):  
Paulette S. McWilliam ◽  
Bruce F. Phillips
Keyword(s):  
Energy Levels ◽  
Field Studies ◽  
Shelf Break ◽  
Energy Reserves ◽  
Specific Level ◽  
Larval Phase ◽  
Larval Recruitment ◽  
Panulirus Cygnus ◽  
Break Region ◽  
Nutritional Studies

The final phyllosoma of Panulirus cygnus metamorphoses to a non-feeding puerulus that lives on energy reserves accumulated in the final larva, and the metamorphic moult occurs mainly in the slope region adjoining the shelf-break off Western Australia. A review of the literature on field studies, laboratory rearing and nutritional studies of phyllosomal and other decapod zoeal larvae provided no evidence that metamorphosis in P. cygnus (or other shallow-water palinurids) is triggered by a direct environmental cue. It did indicate that metamorphosis results from the culmination of sustained nutrition and reserve energy levels through the later larval phase. Therefore, since the puerulus is secondarily lecithotrophic, it is considered that metamorphosis occurs only after the final phyllosoma has reached some critical, specific, level of stored energy reserves. Appropriate food for later larval development and successful metamorphosis of P. cygnus is more abundant in the shelf-break region (than further offshore) because this is a region of high plankton and micronekton biomass dominated by the Leeuwin Current. It also explains why metamorphosis occurs mainly in the shelf-break region. This review indicates research necessary for evaluation of the present interpretation and of larval recruitment processes in this species.

Mixing and bottom water formation in the shelf break region of the southern Weddell Sea

1987 ◽  
Vol 34 (11) ◽  
pp. 1771-1794 ◽  
Author(s):  
Theodore D. Foster ◽  
Arne Foldvik ◽  
Jason H. Middleton
Keyword(s):  
Bottom Water ◽  
Shelf Break ◽  
Weddell Sea ◽  
Water Formation ◽  
Break Region ◽  
Bottom Water Formation

Baroclinic eddies bordering the celtic sea in late summer

1979 ◽  
Vol 59 (3) ◽  
pp. 689-703 ◽  
Author(s):  
R. D. Pingree
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Large Scale ◽  
Late Summer ◽  
Shelf Break ◽  
Sea Surface ◽  
Growth Time ◽  
Infra Red ◽  
Celtic Sea ◽  
Break Region

Infra-red images of sea surface temperature indicate that shelf sea frontal regions around the British Isles are characterized by cyclonic eddies with typical wavelengths between 20 and 40 km and growth time scales in the order of a day. A similar analysis for the shelf-break region of the Celtic Sea based on the interpretation of structures observed in infra-red sattllite images and a survey at sea shows that this region is also characterized by eddies. These eddies are usually associated with a general lowering of sea surface temperature that occurs over the shelf-break region in late summer. In this paper, observed eddy scales are compared with estimates based on theory originally developed for large-scale (3000 km wavelength) atmospheric eddies and the role of eddies in cross-frontal exchange is examined in more detail.

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