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.

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.

Age-related trends in otolith chemistry of Merluccius merluccius from the north-eastern Atlantic Ocean and the western Mediterranean Sea

2005 ◽  
Vol 56 (5) ◽  
pp. 599 ◽  
Author(s):  
B. Morales-Nin ◽  
S. C. Swan ◽  
J. D. M. Gordon ◽  
M. Palmer ◽  
A. J. Geffen ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Western Mediterranean ◽  
Elemental Concentrations ◽  
The Core ◽  
The North ◽  
Western Mediterranean Sea ◽  
Growth Increments ◽  
Age Related ◽  
North Eastern ◽  
The Mediterranean

Sagittal otoliths of European hake obtained from five geographic locations in the north-eastern Atlantic and western Mediterranean were examined using laser ablation and inductively coupled plasma mass spectrometry. Otolith sections were analysed for the isotopes 24Mg, 55Mn, 66Zn, 85Rb, 86Sr, 138Ba and 208Pb, measured relative to 43Ca counts. These analyses considered only age 0 (core area) and ages 1 to 3. Age-related trends in otolith elemental composition were observed in hake from all areas, but were masked by variability between locations. Elemental concentrations generally decreased outside the core, with some increase at age 3. The composition of the otolith core was very distinct from that of the other growth increments. In the Mediterranean, part of this differentiation was a result of Mn, which was present in the core at high concentrations compared with the rest of the otolith. Mediterranean otoliths also had higher concentrations of Sr, Zn and Ba in the core. For most samples a similar trend was observed, although samples from one of the Mediterranean areas showed some differences, mainly in the concentrations of Mg and Sr. These results provide new empirical evidence of the variation in elemental concentrations across hake otoliths with age, at least throughout the first 3 years of life.

scholarly journals Immunohistopathological response against anisakid nematode larvae and a coccidian in Micromesistius poutassou from NE Atlantic waters

2021 ◽  
Vol 95 ◽  
Author(s):  
B. Sayyaf Dezfuli ◽  
E. Simoni ◽  
G. Bosi ◽  
M. Palomba ◽  
S. Mattiucci ◽  
...  
Keyword(s):  
Sensu Stricto ◽  
Cell Swelling ◽  
Epithelioid Cells ◽  
Larval Stages ◽  
The North ◽  
Eastern Atlantic Ocean ◽  
Larval Infection ◽  
High Infection ◽  
North Eastern ◽  
Multilocus Approach

Abstract A survey on Anisakis simplex (sensu stricto (s.s.)) from blue whiting, Micromesistius poutassou, in the north-eastern Atlantic Ocean revealed the occurrence of high infection levels of third larval stages in visceral organs and flesh. Larvae were genetically identified with a multilocus approach as A. simplex (s.s.). Histochemical, immunohistochemical and ultrastructural observations were conducted on 30 M. poutassou specimens. Gonads, pyloric caeca and flesh harboured encapsulated larvae of A. simplex (s.s.) but no intense host reaction was encountered around the parasite in the above organs. In the liver, the most infected organ, the larvae co-occurred with the coccidian Goussia sp. Within the granuloma around the A. simplex (s.s.) larvae, two concentric layers were recognized, an inner mostly comprising electron-dense epithelioid cells and an outer layer made of less electron-dense epithelioid cells. Macrophages and macrophage aggregates (MAs) were abundant out of the granulomas, scattered in parenchyma, and inside the MAs, the presence of engulfed Goussia sp. was frequent. In liver tissue co-infected with Goussia sp. and A. simplex (s.s.), hepatocytes showed cytoplasmic rarefaction and acute cell swelling. Results suggest that the host-induced encapsulation of A. simplex (s.s.) larvae is a strategic compromise to minimize collateral tissue damage around the larval infection sites, to facilitate the survival of both parasite and host.

scholarly journals Dynamical Downscaling of ERA5 Data on the North-Western Mediterranean Sea: From Atmosphere to High-Resolution Coastal Wave Climate

2021 ◽  
Vol 9 (2) ◽  
pp. 208
Author(s):  
Valentina Vannucchi ◽  
Stefano Taddei ◽  
Valerio Capecchi ◽  
Michele Bendoni ◽  
Carlo Brandini
Keyword(s):  
Mediterranean Sea ◽  
Wind Wave ◽  
Dynamical Downscaling ◽  
Wave Climate ◽  
Western Mediterranean ◽  
Limited Area ◽  
Computational Domain ◽  
Wave Hindcast ◽  
The North ◽  
Western Mediterranean Sea

A 29-year wind/wave hindcast is produced over the Mediterranean Sea for the period 1990–2018. The dataset is obtained by downscaling the ERA5 global atmospheric reanalyses, which provide the initial and boundary conditions for a numerical chain based on limited-area weather and wave models: the BOLAM, MOLOCH and WaveWatch III (WW3) models. In the WW3 computational domain, an unstructured mesh is used. The variable resolutions reach up to 500 m along the coasts of the Ligurian and Tyrrhenian seas (Italy), the main objects of the study. The wind/wave hindcast is validated using observations from coastal weather stations and buoys. The wind validation provides velocity correlations between 0.45 and 0.76, while significant wave height correlations are much higher—between 0.89 and 0.96. The results are also compared to the original low-resolution ERA5 dataset, based on assimilated models. The comparison shows that the downscaling improves the hindcast reliability, particularly in the coastal regions, and especially with regard to wind and wave directions.

scholarly journals Temperature statistics above a deep-ocean sloping boundary

2015 ◽  
Vol 775 ◽  
pp. 415-435 ◽  
Author(s):  
Andrea A. Cimatoribus ◽  
H. van Haren
Keyword(s):  
Deep Ocean ◽  
Passive Scalar ◽  
Convective Activity ◽  
Flow State ◽  
Ocean Turbulence ◽  
The North ◽  
Numerical Studies ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
Turbulence Scaling

We present a detailed analysis of temperature statistics in an oceanographic observational dataset. The data are collected using a moored array of thermistors,$100~\text{m}$tall and starting$5~\text{m}$above the bottom, deployed during four months above the slopes of a Seamount in the north-eastern Atlantic Ocean. Turbulence at this location is strongly affected by the semidiurnal tidal wave. Mean stratification is stable in the entire dataset. We compute structure functions, of order up to 10, of the distributions of temperature increments. Strong intermittency is observed, in particular, during the downslope phase of the tide, and farther from the solid bottom. In the lower half of the mooring during the upslope phase, the temperature statistics are consistent with those of a passive scalar. In the upper half of the mooring, the temperature statistics deviate from those of a passive scalar, and evidence of turbulent convective activity is found. The downslope phase is generally thought to be more shear-dominated, but our results suggest on the other hand that convective activity is present. High-order moments also show that the turbulence scaling behaviour breaks at a well-defined scale (of the order of the buoyancy length scale), which is however dependent on the flow state (tidal phase, height above the bottom). At larger scales, wave motions are dominant. We suggest that our results could provide an important reference for laboratory and numerical studies of mixing in geophysical flows.

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.

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