The diversity, distribution and status of deep-water elasmobranchs in the Rockall Trough, north-east Atlantic Ocean

2015 ◽  
Vol 87 (6) ◽  
pp. 1469-1488 ◽  
Author(s):  
F. C. Neat ◽  
F. Burns ◽  
E. Jones ◽  
T. Blasdale
Author(s):  
Rhian G. Waller ◽  
Paul A. Tyler

Gametogenesis and reproductive periodicity of the solitary scleractiniansFlabellum alabastrum(from the Rockall Trough) andF. angulare(from the Porcupine Seabight) were investigated. Samples were collected between depths from 1370 to 2190 m forF. alabastrumand 2412 to 2467 m forF. angulare. Both species showed gonochorism with a 1:1 sex-ratio and broadcast spawning of gametes is inferred from the lack of brooded planulae. Oocyte sizes were large in both species (925 μm inF. alabastrumand 1015 μm inF. angulare), suggesting lecithotrophic larval development. Fecundity and periodicity of oocyte development differed between the two species.Flabellum alabastrumproduced a maximum of 2800 oocytes per polyp quasi-continuously, whereas the deeper speciesF. angulareproduced a maximum of 550 oocytes per polyp either seasonally or periodically. Both species showed size-dependent fecundity. The data show a decrease in oocyte size and fecundity with depth, in concordance with other deep-water scleractinian species.


Author(s):  
M.W. Clarke

A number of chondrichthyan fish species were caught on long-line in the Rockall Trough (north-east Atlantic) in 1997, which are first records for this area; Raja hyperborea, Raja kukujevi and Raja fullonica. The occurrence of R. hyperborea, usually found in colder boreal waters appears to be temperature related. The presence of the deep water squaliform shark Centrophorus uyato in the area was also confirmed and several species were caught at previously undocumented depths.The Rockall Trough is an extension of the North Atlantic deep environment (Mauchline, 1990). A long-line survey was undertaken in August 1997 on the eastern and southern slopes of the Rockall Trough (Figure 1), fishing gear and procedures are described by Connolly (1997). Identifications were undertaken by means of several texts (Compagno, 1984; Whitehead, et al., 1984; Stehmann, 1997). The specimens described below were lodged in the National Museum of Ireland (NMI) and the Hamburg University Zoological Museum, Germany (ZMH). Depth ranges, positions and catalogue numbers of the specimens described are given in Table 1.


Author(s):  
P. M. Hargreaves

The vertical distribution of Decapoda (Crustacea) at deep-water stations in the Rockall Trough and the Porcupine Seabight is discussed and compared to the near-bottom distribution of Decapoda on the continental slope of the Seabight. The vertical distribution of some species is unaffected by the shallowing of the sea floor in the slope area. Other species are found in much higher concentrations near-bottom over the slope than at similar depths at the adjacent deep-water stations and at least one species extends its lower vertical range. It is suggested that the increased food availability near-bottom may be the principal factor influencing aggregation.


Marine Policy ◽  
2017 ◽  
Vol 76 ◽  
pp. 159-168 ◽  
Author(s):  
Inma Álvarez-Fernández ◽  
Nuria Fernández ◽  
Noela Sánchez-Carnero ◽  
Juan Freire

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