Allopodocotyle margolisi n.sp. (Digenea: Opecoelidae) from the deep-sea fish Coryphaenoides (Chalinura) mediterraneus in the northeastern Atlantic

An opecoelid digenean parasite, Allopodocotyle margolisi n.sp., is described from the macrourid fish Coryphaenoides (Chalinura) mediterraneus from benthopelagic waters of the North Rockall Trough, NE Atlantic Ocean. This is the first member of the genus to be recorded from deep-sea fishes. It is distinguished from its neritic congeners on the basis of features that include the arrangement of the testes, length of the cirrus-sac, and sucker-ratio. Its distinctness from other opecoelids from deep-sea fishes is also commented upon.

Seismic investigations of sedimentary structure in the northern Rockall Trough—a synopsis

Single channel, analogue, seismic reflection profiles using Sparker and small capacity Air gun sources were used to investigate late Tertiary and Quaternary sedimentation both around the margins and on the floor of the north Rockall Trough. The data complement, by being intermediate in penetration and resolution, previous seismic studies; particularly, they allow the upper 500 m of the sediment sequence to be examined in greater detail than hitherto.

Water masses and mesoscale circulation of North Rockall Trough waters during JASIN 1978

During the Joint Air-Sea Interaction Experiment (JASIN 1978) grids of temperature and salinity profiles were worked within an area of about 150 km x 150 km to obtain details of the mesoscale circulation around the location of the experiment in the North Rockall Trough. Data were also obtained from moored current meters and from research vessel observations in the surrounding waters. In the uppermost layers two water masses were present, North Atlantic Water from southern parts of the Rockall Trough and fresher Modified North Atlantic Water from the north and west. Beneath these an intermediate water formed by Atlantic Water in contact with Subarctic Intermediate Water was found and at greater depth distinctions could be drawn between water from the south, water with an admixture of Norwegian Sea Deep Water from the Scotland-Iceland ridges and, more sparse, water with a component of Arctic Intermediate Water from the Faroe-Shetland Channel. The patterns of circulation were found to change little between the lower depths and 200 m. An anticyclonic eddy of fresher, colder water moved westwards across the northern half of the grid at about 1.4 km day-1, the northern sector of a more saline meander expanded westwards across the southern part of the area, and smaller less well resolved circulations were found in the west. The eddy contained water of overflow origin and the meander appears to have been part of the main Atlantic to Norwegian Sea current. When inverse analysis was applied to two of the data sets to investigate choices of reference level, zero velocity at the bottom gave the only physically realistic solution. Although the necessary process of averaging the observations to data points 45 km apart obscured the resolution of smaller features, confidence in the reference level that satisfied the inverse analysis allowed classical geostrophic analysis to be performed on the full set of stations, supporting and quantifying the earlier analysis of patterns. The influence of the deeper circulation can be seen in the modification of the thermohaline structure in the seasonal thermocline and mixed layers. Boundaries between adjacent upper water masses were distorted by underlying convergences or fragmented by horizontal shears.