Habitat, behaviour and colour patterns of orange roughy Hoplostethus atlanticus (Pisces: Trachichthyidae) in the Bay of Biscay

2002 ◽  
Vol 82 (2) ◽  
pp. 321-331 ◽  
Author(s):  
Pascal Lorance ◽  
Franz Uiblein ◽  
Daniel Latrouite
Keyword(s):  
Food Resource ◽  
High Water ◽  
Foraging Strategy ◽  
Fine Tuning ◽  
Bay Of Biscay ◽  
Orange Roughy ◽  
North East ◽  
Peripheral Areas ◽  
Colour Patterns ◽  
Red Coloration

Analyses of 13 submersible dives on the continental slope of the Bay of Biscay (north-east Atlantic) showed that: (i) orange roughy formed dense aggregation of more than 4000 individuals per ha close to the bottom of a small underwater canyon. In all other study areas only a few individuals were observed. Orange roughy aggregations are probably associated with areas of high water mass movements and mixing; (ii) most individuals observed within this aggregation or in its peripheral areas were behaviourally inactive and could be approached with the submersible at close distance; (iii) a large number of these orange roughy showed a completely pigmentless white, or weak red coloration, never observed from specimens caught in trawls. Two individuals which were disturbed by the submarine changed from white to the ‘typical’ red coloration.These observations suggest fine tuning of the foraging strategy and life cycle of the species. It is speculated that, as an active predator of a sparse food resource, orange roughy has developed adaptations to exploit areas with specific hydrological conditions which offer high prey encounter rates and shelter during metabolic relaxation phases between foraging trips.

scholarly journals Evolutionary fine-tuning of background-matching camouflage among geographical populations in the sandy beach tiger beetle

2020 ◽  
Vol 287 (1941) ◽  
pp. 20202315
Author(s):  
Nayuta Yamamoto ◽  
Teiji Sota
Keyword(s):  
Sequence Data ◽  
Evolutionary Process ◽  
Fine Tuning ◽  
Colour Pattern ◽  
Tiger Beetle ◽  
Background Matching ◽  
Geographical Populations ◽  
Geographical Distances ◽  
The Japanese Archipelago ◽  
Colour Patterns

Background-matching camouflage is a widespread adaptation in animals; however, few studies have thoroughly examined its evolutionary process and consequences. The tiger beetle Chaetodera laetescripta exhibits pronounced variation in elytral colour pattern among sandy habitats of different colour in the Japanese Archipelago. In this study, we performed digital image analysis with avian vision modelling to demonstrate that elytral luminance, which is attributed to proportions of elytral colour components, is fine-tuned to match local backgrounds. Field predation experiments with model beetles showed that better luminance matching resulted in a lower attack rate and corresponding lower mortality. Using restriction site-associated DNA (RAD) sequence data, we analysed the dispersal and evolution of colour pattern across geographical locations. We found that sand colour matching occurred irrespective of genetic and geographical distances between populations, suggesting that locally adapted colour patterns evolved after the colonization of these habitats. Given that beetle elytral colour patterns presumably have a quantitative genetic basis, our findings demonstrate that fine-tuning of background-matching camouflage to local habitat conditions can be attained through selection by visual predators, as predicted by the earliest proponent of natural selection.

Octomagelona bizkaiensis (Polychaeta: Magelonidae) a new genus and species from the Capbreton Canyon (Bay of Biscay, north-east Atlantic)

2001 ◽  
Vol 81 (2) ◽  
pp. 221-224 ◽  
Author(s):  
Florencio Aguirrezabalaga ◽  
Argiloa Ceberio ◽  
Dieter Fiege
Keyword(s):  
New Genus ◽  
Bay Of Biscay ◽  
New Genus And Species ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The Family ◽  
North Eastern

Octomagelona bizkaiensis (Annelida: Polychaeta), a new genus and species of the family Magelonidae is described from the north-eastern Atlantic. The specimens were collected from the Capbreton Canyon, Bay of Biscay, at a depth of 1000–1040 m. The new genus and species differs from all known genera and species of the family Magelonidae by the presence of eight instead of nine thoracic chaetigers.

scholarly journals Interannual evolutions of (sub)mesoscale dynamics in the Bay of Biscay

2017 ◽  
Author(s):  
Guillaume Charria ◽  
Sébastien Theetten ◽  
Frédéric Vandermeirsch ◽  
Özge Yelekçi ◽  
Nicole Audiffren
Keyword(s):  
High Resolution ◽  
Mixed Layer ◽  
Large Scale ◽  
Mixed Layer Depth ◽  
Relative Vorticity ◽  
Circulation System ◽  
Western Boundary ◽  
Bay Of Biscay ◽  
Coastal System ◽  
North East

Abstract. In the North-East Atlantic Ocean, the Bay of Biscay is an intersection between a coastal constrained dynamics (wide continental shelf and shelf break regions) and an eastern boundary circulation system. In this framework, the eddy kinetic energy is one order of magnitude lower than in western boundary systems. To explore this coastal complex system, a high resolution (1 km, 100 vertical sigma layers) model experiment including tidal dynamics over a period of 10 years (2001–2010) has been implemented. The ability of the numerical environment to reproduce main patterns over interannual scales is demonstrated. Based on this experiment, the features of the (sub)mesoscale processes are described in the deep part of the region (i.e. abyssal plain and continental slope). A system with the development of mixed layer instabilities at the end of winter is highlighted. Beyond confirming an observed behaviour of seasonal (sub)mesoscale activity in other regions, the simulated period allows exploring the interannual variability of these structures. A relationship between winter maximum of mixed layer depth and the intensity of (sub)mesoscale related activity (vertical velocity, relative vorticity) is revealed and can be explained by large scale atmospheric forcings (e.g. the cold winter in 2005). The first high resolution exploration of this 3D coastal system shows the importance of (sub)mesoscale activity in this region and its evolution implying a potential significant impact on vertical and horizontal mixing.

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