Comparative study of the Genus Isurus (Rafinesque, 1810), and description of a form (Marrajo Criollo) apparently endemic to the Azores

1992 ◽  
Vol 43 (1) ◽  
pp. 109 ◽  
Author(s):  
JA Moreno ◽  
JQ Moron
Keyword(s):  
Western Mediterranean ◽  
Distinctive Features ◽  
The North ◽  
Western Mediterranean Sea ◽  
Shortfin Mako ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
Western Morocco ◽  
First Time ◽  
North Western

Numerous captures of mako sharks (Isurus sp.) are made annually by the Spanish longline fishing fleet in the north-eastern Atlantic Ocean and the western Mediterranean Sea. Sampling of catches allowed us to compare the morphology of two species of Isurus (I. Oxyrinchus and I. Paucus) and to document the variations due to size or sex observed in populations exploited by the different fisheries. The distinctive features of a form apparently endemic to the Azores ('marrajo criollo') are defined, and the form's taxonomic identity is discussed. This form is possibly a distinct population of shortfin mako (I. Oxyrinchus). The presence of longfin mako (I. Paucus) is confirmed in waters off north-western Morocco, and this species is recorded for the first time off the Iberian peninsula.

The true identities of the slipper lobsters Nisto laevis and Nisto asper (Crustacea: Decapoda: Scyllaridae) verified by DNA analysis

2009 ◽  
Vol 23 (1) ◽  
pp. 77 ◽  
Author(s):  
Ferran Palero ◽  
Guillermo Guerao ◽  
Paul F. Clark ◽  
Pere Abelló
Keyword(s):  
Dna Analysis ◽  
Historical Review ◽  
Western Mediterranean ◽  
History Museum ◽  
Larval Stages ◽  
The North ◽  
Western Mediterranean Sea ◽  
Eastern Atlantic Ocean ◽  
Reference Collection ◽  
North Western

In 1885, Sarato created Nisto as a new genus of slipper lobster and assigned two species to his taxon, namely Nisto laevis and N. asper. Bouvier later regarded these two species as post-larval stages of Scyllarus arctus (Linnaeus, 1758). This viewpoint of two post-larval stages has been accepted and retained, including being cited in the most recent scyllarid literature. The discovery of N. laevis and N. asper specimens in the reference collection of the Natural History Museum, London and the capture of three nisto-stage individuals, one in the north-western Mediterranean Sea and two in the Gulf of Cádiz (eastern Atlantic Ocean) have facilitated a historical review into the post-larval stages of S. arctus, as well as new detailed morphological descriptions. From the present study, it has been possible to describe and illustrate the nisto stages of S. arctus and S. pygmaeus (Bate, 1888) and to resolve the true identities of N. laevis and N. asper by DNA analysis. Accordingly, N. laevis has been identified as the nisto stage of S. pygmaeus and N. asper as that of S. arctus.

Reproductive biology of the Bigeye Thresher Shark, Alopias superciliosus (Lowe, 1939)

1992 ◽  
Vol 43 (1) ◽  
pp. 77 ◽  
Author(s):  
J Moreno ◽  
J Moron
Keyword(s):  
Gravid Female ◽  
Western Mediterranean ◽  
Embryo Morphology ◽  
The North ◽  
Western Mediterranean Sea ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
Imaginary Line ◽  
Thresher Shark ◽  
Gravid Females

More than 1000 specimens of Alopias superciliosus from fisheries exploited by the Spanish fishing fleet in the north-eastern Atlantic Ocean (from Cape SLo Vicente to the Ivory Coast) and in the western Mediterranean Sea (i.e. west of an imaginary line between Monaco and Algiers) were observed in discontinuous samples between 1981 and 1989. Ten gravid females, 20 fetuses and a large number of egg capsules were studied in detail. The embryo morphology provided evidence of ovophagy. Size at birth was probably at least 100 cm. Six males with total lengths of 400-410 cm exceeded the previously reported maximum length for this sex. The characteristics of the claspers and deferent ducts suggested a total length at maturity of about 276 cm for males. The smallest gravid female was 341 cm long. Also described are litter sizes, indications of reproductive seasonality, and the possible existence of a nursery area in waters off the south-western Iberian peninsula.

Reproductive biology of the seastar Ceramaster grenadensis from the deep north-western Mediterranean Sea

2015 ◽  
Vol 95 (4) ◽  
pp. 805-815 ◽  
Author(s):  
A. Mecho ◽  
U. Fernandez-Arcaya ◽  
E. Ramirez-Llodra ◽  
J. Aguzzi ◽  
J.B. Company
Keyword(s):  
Mediterranean Sea ◽  
Population Distribution ◽  
Gonad Index ◽  
Western Mediterranean ◽  
The North ◽  
Western Mediterranean Sea ◽  
Continuous Reproduction ◽  
First Time ◽  
Wide Geographic Distribution ◽  
North Western

Ceramaster grenadensis is one of the most abundant bathyal seastars in the north-western Mediterranean Sea and also presents a wide geographic distribution in the Atlantic Ocean. As with other species in this genus, little information is available on the biology and reproductive strategy of C. grenadensis. In this context, we describe for the first time the reproductive cycle of this species from bathyal depths in the north-western Mediterranean Sea. Specimens (N = 141) were collected seasonally from 194 benthic trawls (141 Otter Trawls and 53 Agassiz trawls) conducted during 10 cruises from October 2008 to April 2013. Open slope and canyon systems were sampled at depths between 900 and 2250 m. The population distribution of C. grenadensis showed a depth-related structure, with the smaller adult specimens and juveniles present at greater depths. Sex ratio was 2:1 females per male, constant among seasons and depths. Histological analyses of the gonads showed an asynchronous ovarian organization, with previtellogenic and vitellogenic oocytes throughout the year. These oogenesis patterns suggest a continuous reproduction. However, the Pyloric Caeca Index (PCI) decreased in summer while the Gonad Index (GI) increased in autumn in males, suggesting a higher spawning capacity in autumn. In both sexes, an increasing GI and PCI trend was observed with increasing depth.

scholarly journals Foraging dives of sperm whales in the north-western Mediterranean Sea

2012 ◽  
Vol 92 (8) ◽  
pp. 1799-1808 ◽  
Author(s):  
Alexandre Gannier ◽  
Estelle Petiau ◽  
Violaine Dulau ◽  
Luke Rendell
Keyword(s):  
Prey Capture ◽  
Sperm Whale ◽  
Western Mediterranean ◽  
Sperm Whales ◽  
The North ◽  
Western Mediterranean Sea ◽  
Single Animal ◽  
Components Analysis ◽  
Passive Acoustic ◽  
North Western

Oceanic odontocetes rely on echolocation to forage on pelagic or benthic prey, but their feeding ecology is difficult to study. We studied sperm whale foraging dives during summer in the north-western Mediterranean, using visual and passive acoustic observations. Clicking and creaking activities were recorded during dives of focal whales, at distances <3000 m using a towed hydrophone and DAT recorder. A total of 52 sperm whales were recorded over at least one full dive cycle. Data were obtained for 156 complete dives in total, including sequences of up to nine consecutive dives. Various dive and environmental variables were entered in multiple linear regression and principal components analysis, as well as estimated mass of whales. Creak rate was 0.80 creak/minute on average, with moderate variance. Bigger whales tended to dive longer at greater depths (as suggested by ascent durations), and emitted more creaks during a dive: 20.2 creaks/dive on average for individuals <24 tons, compared to 25.6 creaks/dive for animals >24 tons of estimated mass. For individual whales, creak rates did not vary significantly with size (range 0.78–0.80 creak/minute), but decreased with time of the day, and increased for shorter foraging phases. For different dives, higher creak rates were also observed earlier in the day, and linked to shorter foraging phases and surface durations. Although the exact significance of creak emissions (i.e. foraging attempt or prey capture) is not precisely determined, creak rates may be reliably used to quantify sperm whale foraging when single animal dives can be followed acoustically.

scholarly journals The impact of Saharan dust on the particulate export in the water column of the North Western Mediterranean Sea

2010 ◽  
Vol 7 (3) ◽  
pp. 809-826 ◽  
Author(s):  
E. Ternon ◽  
C. Guieu ◽  
M.-D. Loÿe-Pilot ◽  
N. Leblond ◽  
E. Bosc ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Mass Flux ◽  
Total Mass ◽  
Spring Bloom ◽  
Western Mediterranean ◽  
Saharan Dust ◽  
The North ◽  
Western Mediterranean Sea ◽  
Total Mass Flux ◽  
North Western

Abstract. Simultaneous measurements of atmospheric deposition and of sinking particles at 200 and 1000 m depth, were performed in the Ligurian Sea (North-Western Mediterranean) between 2003 and 2007, along with phytoplanktonic activity derived from satellite images. Atmospheric deposition of Saharan dust particles was very irregular and confirmed the importance of sporadic high magnitude events over the annual average (11.4 g m−2 yr−1 for the 4 years). The average marine total mass flux was 31 g m−2 yr−1, the larger fraction being the lithogenic one (~37%). The marine total mass flux displayed a seasonal pattern with a maximum in winter, occurring before the onset of the spring bloom. The highest POC fluxes did not occur during the spring bloom nor could they be directly related to any noticeable increase in the surface phytoplanktonic biomass. Over the 4 years of the study, the strongest POC fluxes were concomitant with large increases of the lithogenic marine flux, which had originated from either recent Saharan fallout events (February 2004 and August 2005), from "old" Saharan dust "stored" in the upper water column layer (March 2003 and February 2005), or alternatively from lithogenic material originating from Ligurian riverine flooding (December 2003, Arno, Roya and Var rivers). Those associated export fluxes defined as "lithogenic events", are believed to result from a combination of forcing (winter mixing or Saharan events, in particular extreme ones), biological (zooplankton) activity, and also organic-mineral aggregation inducing a ballast effect. By fertilising the surface layer, mixed Saharan dust events were shown to be able to induce "lithogenic events" during the stratification period. These events would be more efficient in transferring POC to the deeper layers than the spring bloom itself. The extreme Saharan event of February 2004 exported ~45% of the total annual POC, compared to an average of ~25% for the bloom period. This emphasises the role played by these "lithogenic events", and in particular those that are induced by the more extreme Saharan events, in the carbon export efficiency in the North-western Mediterranean Sea.

scholarly journals A new species of Pista Malmgren, 1866 (Polychaeta, Terebellidae) from the north-western Mediterranean Sea

ZooKeys ◽  
2019 ◽  
Vol 838 ◽  
pp. 71-84
Author(s):  
Céline Labrune ◽  
Nicolas Lavesque ◽  
Paulo Bonifácio ◽  
Pat Hutchings
Keyword(s):  
New Species ◽  
Mediterranean Sea ◽  
Anterior Part ◽  
Posterior Part ◽  
Western Mediterranean ◽  
Single Pair ◽  
The North ◽  
Western Mediterranean Sea ◽  
North Western ◽  
A New Species

A new species of Terebellidae, Pistacolinisp. n., has been identified from the harbour of Banyuls-sur-Mer, north-western Mediterranean Sea. This new species was found in very high densities, exclusively in gravelly sand deposited manually, and was not found in the original source habitat of the gravel. This species is characterized by the colour of the ventral shields with pinkish anterior part and a blood red posterior part in live specimens, a pair of unequal-sized plumose branchiae inserted on segment II and anterior thoracic neuropodia with long-handled uncini. The presence of long-handled uncini even in the smallest specimens constitutes the major difference between Pistacolinisp. n. and other Pista species with a single pair of branchiae such as P.lornensis and P.bansei.

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