Biodiversity and biogeography in heterospecific teleostean (Gadidae) – copepod (Lernaeocera) associations

1993 ◽  
Vol 71 (8) ◽  
pp. 1639-1645 ◽  
Author(s):  
Claire Tirard ◽  
Patrick Berrebi ◽  
André Raibaut ◽  
François Renaud
Keyword(s):  
Geographical Area ◽  
Western Mediterranean ◽  
Merluccius Merluccius ◽  
Predator Prey ◽  
The North ◽  
Large Sector ◽  
The North Sea ◽  
Merlangius Merlangus ◽  
The Mediterranean ◽  
Host Parasite

This genetic study confirms the validity of two controversial parasite species, Lernaeocera branchialis and Lernaeocera lusci (Copepoda, Pennellidae). These species cohabit throughout a large sector of the North Sea and the Atlantic Ocean, parasitizing Merlangius merlangus and Trisopterus luscus (Teleostei, Gadidae), respectively. In the Mediterranean Sea, it was L. branchialis that was described initially. We have shown, however, that it is L. lusci that parasitizes T. luscus and Merluccius merluccius in this geographical area. The distribution of L. lusci, as well as that of its host, T. luscus, must extend into the Mediterranean. Lernaeocera lusci has colonized a phylogenetically distant host (Merluccius merluccius) in the Mediterranean and our results show that this species has become the preferred host for the maturation of L. lusci in this region. In addition, we have demonstrated the existence of genetic differentiation between T. luscus from the Atlantic and from the western Mediterranean. Thus, it is possible that the specialization of L. lusci in a new resource (M. merluccius) in the Mediterranean might be related to biological changes undergone by this copepod's original host, Trisopterus luscus. In contrast to other parasite groups such as the Monogenea, the specialization of species of the genus Lernaeocera would appear to depend more on ecological parameters (relative abundance and availability of resources) than on phylogenetic constraints. The relationships within these host–parasite systems are therefore compared with the predator–prey relationships.

Encouragement to Others, 1650–1780

The Great Sea ◽  
2011 ◽  
Author(s):  
David Abulafia
Keyword(s):  
Gain Control ◽  
Western Mediterranean ◽  
Spanish Empire ◽  
Political Realism ◽  
The North ◽  
Oliver Cromwell ◽  
The North Sea ◽  
The Mediterranean ◽  
Confessional Identity ◽  
The Relationship

In the course of the seventeenth century the character of the relationship between the European states changed dramatically, with important repercussions in the Mediterranean. Until the end of the Thirty Years’ War in 1648, Catholic confronted Protestant, and confessional identity was an issue of surpassing significance for the competing powers in Europe. After 1648, a greater degree of political realism, or cynical calculation, began to intrude. Within a few years, it was possible for the English arch-Protestant Oliver Cromwell to cooperate with the Spanish king, while English suspicion of the Dutch led to conflict in the North Sea. The character of English involvement in the Mediterranean changed: royal fleets began to intervene and the English (after union with Scotland in 1707, the British) sought out permanent bases in the western Mediterranean: first Tangier, then Gibraltar, Minorca and, in 1800, Malta. The period from 1648 to the Napoleonic Wars was marked, therefore, by frequent about-turns as the English switched from Spanish to French alliances, and as the whole question of the Spanish royal succession divided Europe and opened up the prospect of spoils from a declining Spanish empire in the Mediterranean. While Spain’s difficulties were obvious, it was less clear that the Ottomans had passed their peak: the Ottoman siege of Vienna in 1683 was unsuccessful, but in the Mediterranean Turkish galleys still posed a serious threat, and their Barbary allies could be relied upon to give support when naval conflict broke out. Even so, the Venetians managed to gain control of the Morea or Peloponnese for several years, and, interestingly, it was they who were the aggressors. Bolder than they had been for some time, the Venetians ambitiously aimed to crack Turkish power in the regions closest to their navigation routes. In 1685 and 1686 they captured and demolished a number of Turkish fortresses on either side of the Morea, culminating in the capture of Nafplion on 30 August 1686. This was only the prelude to an attempt to clean up the Dalmatian coast, starting with the Turkish base at Herceg Novi, which they captured in September 1687.

scholarly journals Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) in the North Sea

2014 ◽  
Vol 71 (6) ◽  
pp. 1342-1355 ◽  
Author(s):  
Xochitl Cormon ◽  
Christophe Loots ◽  
Sandrine Vaz ◽  
Youen Vermard ◽  
Paul Marchal
Keyword(s):  
North Sea ◽  
Linear Models ◽  
Spatial Dynamics ◽  
Distribution Patterns ◽  
Trawl Survey ◽  
Spatial Interactions ◽  
Merluccius Merluccius ◽  
The North ◽  
Sediment Types ◽  
The North Sea

Spatial interactions between saithe (Pollachius virens) and hake (Merluccius merluccius) were investigated in the North Sea. Saithe is a well-established species in the North Sea, while occurrence of the less common hake has recently increased in the area. Spatial dynamics of these two species and their potential spatial interactions were explored using binomial generalized linear models (GLM) applied to the International Bottom Trawl Survey (IBTS) data from 1991 to 2012. Models included different types of variables: (i) abiotic variables including sediment types, temperature, and bathymetry; (ii) biotic variables including potential competitors and potential preys presence; and (iii) spatial variables. The models were reduced and used to predict and map probable habitats of saithe, hake but also, for the first time in the North Sea, the distribution of the spatial overlap between these two species. Changes in distribution patterns of these two species and of their overlap were also investigated by comparing species’ presence and overlap probabilities predicted over an early (1991–1996) and a late period (2007–2012). The results show an increase in the probability over time of the overlap between saithe and hake along with an expansion towards the southwest and Scottish waters. These shifts follow trends observed in temperature data and might be indirectly induced by climate changes. Saithe, hake, and their overlap are positively influenced by potential preys and/or competitors, which confirms spatial co-occurrence of the species concerned and leads to the questions of predator–prey relationships and competition. Finally, the present study provides robust predictions concerning the spatial distribution of saithe, hake, and of their overlap in the North Sea, which may be of interest for fishery managers.

scholarly journals Further spreading of the non-indigenous bryozoan Celleporaria brunnea in the Mediterranean Sea: port to port morphological variations

2015 ◽  
Author(s):  
Jasmine Ferrario ◽  
Agnese Marchini ◽  
Martina Marić ◽  
Dan Minchin ◽  
Anna Occhipinti-Ambrogi
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Indigenous Species ◽  
Large Variability ◽  
Morphometric Characters ◽  
Morphological Variations ◽  
The North ◽  
Western Mediterranean Sea ◽  
The Pacific ◽  
The Mediterranean

The Pacific cheilostome bryozoan Celleporaria brunnea (Hincks, 1884), a non-indigenous species already known for the Mediterranean Sea, was recorded in 2013-2014 from nine Italian port localities (Genoa, Santa Margherita Ligure, La Spezia, Leghorn, Viareggio, Olbia, Porto Rotondo, Porto Torres and Castelsardo) in the North-western Mediterranean Sea; in 2014 it was also found for the first time in the Adriatic Sea, in the marina “Kornati”, Biograd na Moru (Croatia). In Italy, specimens of C. brunnea were found in 44 out of 105 samples (48% from harbour sites ad 52% from marinas). These data confirm and update the distribution of C. brunnea in the Mediterranean Sea, and provide evidence that recreational boating is a vector responsible for the successful spread of this species. Previous literature data have shown the existence of differences in orifice and interzooidal avicularia length and width among different localities of the invaded range of C. brunnea. Therefore, measurements of orifice and avicularia were assessed for respectively 30 zooids and 8 to 30 interzooidal avicularia for both Italian and Croatian localities, and compared with literature data, in order to verify the existence of differences in the populations of C. brunnea that could reflect the geographic pattern of its invasion range. Our data show high variability of orifice measures among and within localities: zooids with broader than long orifice coexisted with others displaying longer than broad orifice, or similar values for both length and width. The morphological variation of C. brunnea in these localities, and above all the large variability of samples within single localities or even within colonies poses questions on the reliability of such morphometric characters for inter and intraspecific evaluations.

Spatial and temporal dynamics of European hake (Merluccius merluccius) in the North Sea

2018 ◽  
Vol 75 (6) ◽  
pp. 2033-2044 ◽  
Author(s):  
Arved Staby ◽  
Jon Egil Skjæraasen ◽  
Audrey J Geffen ◽  
Daniel Howell
Keyword(s):  
North Sea ◽  
Temporal Dynamics ◽  
Trawl Survey ◽  
Merluccius Merluccius ◽  
Frequency Distributions ◽  
The North ◽  
The North Sea ◽  
Northern North Sea ◽  
Central North Sea ◽  
European Hake

Abstract Catches of European hake (Merluccius merluccius) in the North Sea have increased substantially during the last decade, even though there is no directed commercial fishery of hake in this area. We analysed the spatial distributions of hake in the northern the parts of its range, (where it is less well-studied), using ICES international bottom trawl survey data from 1997 to 2015. We examine length-frequency distributions for (i) distinct modes enabling the assignment of fish into categories which likely corresponded to the ages 1, 2, and 3+ and (ii) patterns of seasonal spatial distribution for the different groups. Age categories 1 and 2 fish were most abundant in the northern North Sea, and appear to remain in the North Sea until 2 years of age, when they move into deeper waters. Their distribution has expanded into the western-central North Sea in the last decade. Age category 3+ fish were most abundant in the northern and central North Sea during summer, indicating a seasonal influx of large individuals into this area likely associated with spawning activity. The distribution of these older fish has gradually expanded westward in both seasons.

scholarly journals Age composition, growth, movements, meristics and parasites of the whiting, Merlangius merlangus, in the Severn Estuary and Bristol Channel

1988 ◽  
Vol 68 (2) ◽  
pp. 295-313 ◽  
Author(s):  
I. C. Potter ◽  
D. C. Gardner ◽  
P. N. Claridge
Keyword(s):  
Irish Sea ◽  
Age Composition ◽  
Severn Estuary ◽  
Main Site ◽  
The North ◽  
The North Sea ◽  
Inshore Waters ◽  
Merlangius Merlangus ◽  
The Irish Sea ◽  
Copepod Parasites

Samples collected from power station intake screens between 1972 and 1977 have been used to study aspects of the biology of the whiting in the Severn Estuary and Bristol Channel. 0+ whiting generally started appearing in the inner estuary in July, at which time their standard length was at least 38 mm. Their numbers peaked in October and subsequently declined particularly rapidly during the wet winter of 1976/7 when salinities were frequently below 10‰. The size of 0+ whiting in the late autumn and early winter was generally less in the shallows of the Inner Severn Estuary than in neighbouring deeper waters and in the Inner Bristol Channel. Growth rates of 0 + whiting fell within the range of those recorded for the North Sea, but below those generally found in inshore waters and sea lochs on the west coast of Scotland. Following their immigration into inshore waters in the Bristol Channel and Inner Severn Estuary, young whiting became infected with the copepod parasites Lernaeocera branchialis and Clavella adunca and the metacercariae of the heterophyid digenean Cryptocotyle lingua. Prevalence of infection was less in 0+ than older fish and infection by L. branchialis caused a significant decline in condition. As whiting became larger, the main site of attachment of Clavella adunca changed gradually from the wall of the branchial chamber to the primary rakers of the first gill arch. Vertebral counts suggest that the whiting which enter the Inner Bristol Channel and Severn Estuary are not representatives of the populations found in the Irish Sea.

Coastal climatology of the North-Western Mediterranean area for long-term and short-term risk assessment.

2020 ◽  
Author(s):  
Carlo Brandini ◽  
Stefano Taddei ◽  
Valentina Vannucchi ◽  
Michele Bendoni ◽  
Bartolomeo Doronzo ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Resolution ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Climate Trends ◽  
Short Term ◽  
The North ◽  
The Mediterranean ◽  
North Western

<p>In this work we present the results obtained through a dynamic downscaling of the ERA5 reanalysis dataset (hindcast) of ECMWF, using high-resolution meteorological and wave models defined on unstructured computation grids along the Mediterranean coasts, with a particular focus on the North-Western Mediterranean area. Downscaling of the ERA5 meteorological data is obtained through the BOLAM and MOLOCH models (up to a resolution of 2.5 km) which force an unstructured WW3 model with a resolution of up to 500 m along the coast. Models were validated through available meteorological stations, wave buoy data and X-band wave radars, the latter for the purposes of wave spectra validation.</p><p>On the one hand, this allowed, by extracting the time series of some attack parameters of the waves along the coast, and according to the type of coast (rocky coasts, sandy coasts, coastal structures etc.), to compute the return periods and to characterize the impact of any individual storm. On the other hand, it is possible to highlight some trends observed in the last 30 years, during which recent research is showing an increasing evidence  of some changes in global circulation at regional to local scales. These changes also include effects of wind rotation, wave regimes, storm surges, wave-induced coastal currents and coastal morphodynamics. For example, in the North-Western Mediterranean extreme events belonging to cyclonic weather-types circulation with stronger S-SE components (like the storm of October 28-30th 2018 and many others), rather than events associated with perturbations of Atlantic origin and zonal circulation, are becoming more frequent. These long-term wind/wave climate trends can have consequences not only in the assessment of long-term risk due to main morphodynamic variations (ie. coastal erosion), but also in the short-term risk assessment.</p><p>This work was funded by the EU MAREGOT project (2017-2020) and ECMWF Special Project spitbran  “Evaluation of coastal climate trends in the Mediterranean area by means of high-resolution and multi-model downscaling of ERA5 reanalysis” (2018-2020).</p>

Two live sightings of Sowerby's beaked whale (Mesoplodon bidens) from the western Mediterranean (Tyrrhenian Sea)

2017 ◽  
Vol 98 (5) ◽  
pp. 1003-1009 ◽  
Author(s):  
Luca Bittau ◽  
Mattia Leone ◽  
Adrien Gannier ◽  
Alexandre Gannier ◽  
Renata Manconi
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Beaked Whale ◽  
Long Distance ◽  
The North ◽  
Western Mediterranean Sea ◽  
Beaked Whales ◽  
Species Groups ◽  
The Mediterranean

Sowerby's beaked whale (Mesoplodon bidens) was previously known in the Mediterranean Sea from a single live stranding of two individuals in the French Riviera. We report here on two live sightings in the western Mediterranean, central-western Tyrrhenian Sea off eastern Corsica (Montecristo Trough) and off eastern Sardinia (Caprera Canyon) in 2010 and 2012, respectively. In both cases single individuals, possibly the same individual, occurred within groups of Cuvier's beaked whales (Ziphius cavirostris) suggesting inter-specific interactions. Based on our close observations of mixed-species groups of Sowerby's and Cuvier's beaked whales, we hypothesize that some previous long-distance sightings of beaked whales in the Mediterranean may not be reliably attributed to Z. cavirostris. The present sightings and previous live stranding indicate that the western Mediterranean Sea is the easternmost marginal area of M. bidens within the North Atlantic geographic range. Notes on behaviour are also provided.

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.

Sign in / Sign up

Export Citation Format

Share Document