Distribution of deep-water benthic and bentho–pelagic cephalopods from the north-east Atlantic

Author(s):  
Martin A. Collins ◽  
Cynthia Yau ◽  
Louise Allcock ◽  
Michael H. Thurston

The distribution of deep-water (150–4850 m) benthic and bentho–pelagic cephalopods in the north-east Atlantic is described, based on 592 specimens collected from commercial and research trawling. Thirty-six different species of cephalopod belonging to 14 families were identified, though problems remain with the taxonomy of some of the octopod genera. At the shallower depths (150–500 m) sepiolids were the most abundant group with five species identified. Sepiola atlantica, Sepietta oweniana and Rondeletiola minor were restricted to the shallow depths (<300 m), but Neorossia caroli (400–1535 m) and Rossia macrosoma (205–515 m) extended into deeper water. The squids Todaropsis eblanae and Loligo forbesi were also common in shallow areas (<250 m). Among the incirrate octopods, Eledone cirrhosa was found at depths of 208–490 m. Three putative species of Benthoctopus and two of Bathypolypus were identified occupying depths of 250–2700 m. Graneledoneverrucosa was caught at depths of 1785–2095 m. Cirrate octopods dominated the cephalopod catch from the deeper areas, with Opisthoteuthis massyae occurring from 877 to 1398 m, O. grimaldii from 2165 to 2287 m, Stauroteuthissyrtensis from 1425 to 3100 m, Cirroteuthismuelleri from 700 to 4854 m, Cirrothauma murrayi from 2430 to 4850 m and Grimpoteuthis (five putative species) from 1775 to 4877 m. Abundance estimates of the more frequently caught species were calculated from swept areas of trawls and sledges in the Porcupine Seabight and on the Porcupine Abyssal Plain.

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):  
C.M. Howson ◽  
S.J. Chambers

A new species of Ophlitaspongia (Porifera: Microcionidae) from wave-exposed sublittoral rock in the north-east Atlantic is described and compared to the two other species recorded from the genus in the north-east Atlantic. The species known as Ophlitaspongia seriata is considered to be a junior synonym of Halichondria panicea. Consequently, the name O. papilla has been reinstated. The other recorded species O. basifixa, is from deep water. Ophlitaspongia basifixa has characters which differentiate it from Ophlitaspongia sp. nov. The genus Ophlitaspongia has been separated from related genera and reinstated for species in the North Atlantic.


2008 ◽  
Vol 59 (3) ◽  
pp. 214 ◽  
Author(s):  
Teresa Moura ◽  
Mónica C. Silva ◽  
Ivone Figueiredo ◽  
Ana Neves ◽  
Pablo Durán Muñoz ◽  
...  

Two genera of elasmobranchii, Centrophorus and Centroscymnus, include species that represent the highest landings of deep-water sharks caught by fishing fleets operating in the north-east Atlantic. There are morphology-based identification problems among and within genera, and landings of processed shark products further prevent an objective assessment of these species. The present study is the first attempt to test the suitability of using a DNA barcode approach to discriminate accurately among the four most important commercial deep-water shark species: Centrophorus squamosus, Centrophorus granulosus, Centroscymnus coelolepis and, recently discovered in Portuguese ports, Centroscymnus owstoni. Sequence analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) gene revealed low levels of haplotypic and genetic diversities. Higher levels of inter-specific relative to intra-specific divergences allowed discrimination among species, which form reciprocally monophyletic clades. Inclusion of published COI sequences from other species within the same genera revealed haplotype sharing among species, which calls into question the current taxonomy and accuracy of fisheries data available. Amplification of the COI gene coupled with MboI restriction digests was found to be a fast and inexpensive strategy to resolve within genera identification problems. Molecular barcoding constitutes a critical tool for the assessment and implementation of urgent management policies for this group of 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.


1998 ◽  
Vol 78 (4) ◽  
pp. 1385-1388 ◽  
Author(s):  
Afonso Marques

The diet of Synaphobranchus kaupi from the Porcupine Seabight is described. A sample of 110 eel stomachs containing food, were analysed and the general size–depth trend among eels with food in their stomachs. Larger individuals are found in deeper waters. Fish are the main prey for larger eels and crustaceans are preferred by smaller individuals.Synaphobranchus kaupi Johnson, 1862 is a slope dwelling eel, abundant in the north-east Atlantic Ocean from 230 to 2420 m deep on the continental slope (Haedrich & Merrett, 1988). It is the most abundant species on the slopes of the Porcupine Seabight, off south-west Ireland (Merrett et al, 1991; Priede et al., 1994) and was classified as a benthopelagic predator of the fourth level, predator of predators (Saldanha, 1991).The diet of S. kaupi has been described from the slope off the middle Atlantic coast of the USA (Sedberry & Musick, 1978), from the Portuguese slope and in the Bay of Biscay (Saldanha, 1991), from the west African slope (Merrett & Marshall, 1981; Merrett & Domanski, 1985) and from the Rockall Trough (Gordon & Mauchline, 1996).Our specimens were captured during a joint IOS/SAMS survey (Merret et al., 1991). From a total catch of 8792 S. kaupi, captured between 1979 and 1983 in the Porcupine Seabight, ranging from 470 to 2230 m deep, fish stomachs were removed aboard ship and 110 with food were kept in 5% formalin for further analysis.


2000 ◽  
Vol 43 (1) ◽  
pp. 15-31 ◽  
Author(s):  
R. Witbaard ◽  
G.C.A. Duineveld ◽  
J.A. Van der Weele ◽  
E.M. Berghuis ◽  
J.P. Reyss

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