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Background: In Morocco, fish is an important protein source especially, even not exclusively, for coastal communities and marketed fresh all along the coastline. One of the main targets of coastal artisanal fisheries is the European conger (Conger conger, Linnaeus 1758), a widely distributed benthic predatory species of a maximum weight of up to 50 kg. However, information on heavy metal contamination of conger is scarce. Therefore, concentrations of mercury, lead and cadmium were analysed in 108 European conger specimens from nine locations along the along the Atlantic and Mediterranean coasts of Morocco to describe the spatial distribution of heavy metal contamination. Results: The average heavy metal concentration in all conger samples under investigation was 246.90 ± 216.83 µg mercury/kg wet mass, 74.14 ± 87.02 µg lead/kg wet mass and 255.12 ± 287.15 µg cadmium/kg wet mass respectively. Mercury and cadmium showed a clear site-specific bioaccumulation in European conger but lead does not. Hence, the effect of fish length bias on contamination was corrected through a generalized linear model (GLM) prior to any spatial comparison. Conclusions: Different regional hotspots for the three analysed metals are identified and local sources are discussed. Mercury levels in big specimens of European conger exceeded the European threshold level for human consumption at some of the locations under investigation. [ABSTRACT FROM AUTHOR]

The study of Martin et al.[17] found higher Mn/Sr ratios in leptocephalus otoliths [1.66E-05 (mean)] from the Sargasso Sea compared to glass eel otoliths from 11 coastal water sites [5.25E-06 to 9.22E-06 (range of means)]. Chang et al.[1] misquote this study as evidence of a higher Mn concentration in glass eel otoliths compared to leptocephalus larvae from the Sargasso Sea. 17 Martin J. An otolith microchemistry study of possible relationships between the origins of leptocephali of European eels in the Sargasso Sea and the continental destinations and relative migration success of glass eels. [Extracted from the article]

The mysterious food source of anguilliform leptocephali has been difficult to understand, so this review evaluates potential interrelationships among recent discoveries on this subject. There are typically few identifiable gut-content objects in leptocephalus intestines, which usually contain amorphous materials. Gut content observation studies and stable isotope research have suggested that marine snow detrital-type particles are a food source, but this was difficult to validate. Recent gut-content DNA-sequence analyses indicated that small 4–25 mm Sargasso Sea European eel larvae, Anguilla anguilla, frequently ingest calycophoran siphonophore tissues as well as other taxa not likely to be ingested individually. A high-magnification photographic study of Sargasso Sea leptocephalus gut contents recently detected possible hydrozoan tentacles and apparent fatty acid-rich single-celled, heterotrophic thraustochytrid protists (class Labyrinthulomycetes), which have been found in marine snow in previous studies, but are not amplified by some DNA primers. Calycophoran siphonophores are abundant in the Sargasso Sea and have extensive tentacle arrays and short-lived eudoxid reproductive stages that might be appropriate sizes to be eaten directly or contribute to marine snow aggregates. The two groups may be interrelated because thraustochytrids are ubiquitously present decomposers that colonize detrital materials in oceanic and coastal ecosystems, so both siphonophore tissues and thraustochytrids may be present in marine snow consumed by European eel and other leptocephali. Therefore, future research on what leptocephali consume as food should be approached from a size-scaling perspective using systematic direct gut-content observations in combination with appropriate primers for next-generation DNA sequencing. [ABSTRACT FROM AUTHOR]

Gelatinous zooplankton (GZ) such as medusae, ctenophores, siphonophores, pyrosomes and salps are important components of oceanic pelagic communities and small calycophoran siphonophores (CS) are typically abundant at shallow depths. The Sargasso Sea spawning area of the Atlantic catadromous freshwater eels has a regular pattern of shallow autumn to spring temperature fronts. There is limited information about the southern Sargasso Sea GZ fauna, and it is not known which species are distributed across these frontal zones. Plankton samples from a survey of larval European eel (Anguilla anguilla) abundance in March and April 2017 using an Isaacs-Kidd Midwater Trawl (0–300 m, 35 stations, three transects) were used to examine the distribution and abundance of net-captured CS and other GZ species in relation to oceanographic characteristics. More than 2200 specimens of 15 taxa were sub-sampled, with five CS (Abylopsis tetragona, A. eschscholtzii, Chelophyes appendiculata, Eudoxoides spiralis and E. mitra) dominating catches at every station. GZ were most abundant around the 22 and 24 °C isotherms, and higher abundances of CS in the north were correlated with lower water temperature. The widespread presence of CS across the European eel spawning area is consistent with a recent study detecting their DNA sequences in the gut contents of young eel larvae collected in the Sargasso Sea, suggesting CS material was either eaten directly or as part of ingested marine snow particles. The present study shows that both types of organisms occupy the southern Sargasso Sea during the European eel spawning season. [ABSTRACT FROM AUTHOR]

Leptocephali of the shallow-water congrid eel Ariosoma balearicum are abundant during February–April in the Sargasso Sea, and larval and adult meristic data indicates this species includes several regional subpopulations/cryptic species. Four multiple-transect larval surveys (2011, 2014, 2015, 2017) were used to examine the geographic size distribution of two myomere-count types of A. balearicum leptocephali. High-count (HC) larvae were consistently mostly between 80 and 100 mm in size (60–132 mm; 87.9 ± 6.8 mm) as observed previously, and frequently had narrow size ranges. The usually larger LC larvae (78–176 mm; 111.4 ± 26.7 mm) were more abundant in western or central areas. HC larvae tended to decrease in size from west to east and increase from south to north. Catch rates were geographically variable relative to hydrographic structure/frontal positions across the wide 2015 sampling area. Mitochondrial 16 s rRNA sequences of HC and LC larvae show species-level differences, providing evidence of the existence of two cryptic species with different larval dispersal strategies in the Sargasso Sea subtropical gyre region. The HC larvae disperse widely into the gyre, seemingly through Gulf Stream recirculation or eastward frontal-jet flows, and apparently must use directional swimming to cross the Florida Current to recruit into the South Atlantic Bight. LC leptocephali may mostly be retained near the Bahamas, with few larvae dispersing into the gyre. This seems to indicate natural selection occurred for spawning location and larval behavior due to the powerful Florida Current/Gulf Stream, resulting in two completely different spawning and larval dispersal strategies within a local geographic region. [ABSTRACT FROM AUTHOR]

Here, we report on a comprehensive collection of mainly early life cephalopods that were sampled during a research cruise to the Sargasso Sea with the RV Maria S. Merian in April 2015. A total of 2466 cephalopods were caught which belonged to at least 27 species (17 families). The most abundant family was represented by the hooked squids (Onychoteuthidae) with a share of 19.18% of the total cephalopod catch. The subtropical convergence zone (STCZ) was found approximately around 27 °N. The STCZ was characterised by a sharp near-surface temperature gradient and divided the Sargasso Sea into a northern and a southern area. This division was also reflected in the cephalopod community composition. For example, the cranchiid Leachia lemur prevailed in the northern part, and the incirrate octopod, Japetella diaphana, was mainly distributed in the southern part of the study area. Principal component analysis (PCA) and redundancy analysis (RDA) analyses detected a significant correlation between species occurrence and sea surface temperature (SST) as well as a longitudinal gradient with distinct clusters along the five transects from west to east. Ordination analysis (MDS) showed significant differences in the cephalopod assemblages between day and night with midwater forms (Enoploteuthidae, Pyroteuthidae) dominating the night catches, probably due to their upward migration into the top 200 m during the night. [ABSTRACT FROM AUTHOR]

Several surveys and studies have examined the Atlantic anguillid eels' larval distributions, but little is known about their larval growth rates. Otoliths of 17 European eel Anguilla anguilla (8.8-46.0 mm) and 19 American eel Anguilla rostrata (9.8-59.9 mm) leptocephali collected in the Sargasso Sea (25-31°N, 58-70°W) in March and April 2011 were analyzed and their spawning times and larval growth rates were estimated. Ages calculated from the number of otolith increments of European and American eel larvae showed ranges of 10-127 days and 14-233 days, respectively. Linear relationships between age and total length indicated early larval growth rates of 0.31 mm/day for the European eel and 0.35 mm/day for the American eel. This suggested slower growth rates in low temperatures in the Sargasso Sea compared to other anguillid species in the Indo-Pacific, where water temperatures are higher. The back-calculated hatching dates of small leptocephali (8.8-26.7 mm) were in February and March 2011. More American eels hatched in February and more European eels hatched in March. The hatching times of two larger European eel leptocephali (38.7 and 46.0 mm) and a larger American eel leptocephalus (59.9 mm) were back-calculated to November and December 2010 and July 2010, respectively, suggesting hatching times outside of the primary spawning seasons. These novel observations provide important information on the timing of spawning and larval growth characteristics of Atlantic eels, which would benefit from validation by additional otolith studies of leptocephali. [ABSTRACT FROM AUTHOR]

Background: Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. Environmental pollution of fish is a topic of rising attention in Morocco. However, only few studies have been carried out so far, describing the potential threat of organic pollution to Moroccan aquatic ecosystem. Two polycyclic aromatic hydrocarbon (PAH) metabolites, 1-hydroxypyrene (1-OH-Pyr) and 1-hydroxyphenanthrene (1-OH-Phen), were identified and quantified from the bile of 18 European eels ( Anguilla anguilla), 7 Moray ( Muraenidae), and 28 Conger eels ( Conger conger) collected from Moulay Bousselham lagoon and Boujdour coast. The bile metabolites were separated by high-performance liquid chromatography with fluorescence detection. The present study aims to compare the levels of PAH metabolites in fish from the lagoon and the open sea and to compare levels of PAH metabolites in different fish species. Results: The major metabolite present in all fish was 1-hydroxypyrene (

In a process called silvering, European eels prepare for their long-distance migration from European freshwater systems to the Sargasso Sea for reproduction. During this journey, eels perform extended diel vertical migrations, and the concomitant changes in hydrostatic pressure significantly affect the swimbladder, functioning as a buoyancy organ. As the swimbladder is primarily filled with oxygen, the tissue has to cope with extreme hyperoxic conditions, which typically are accompanied by the generation of reactive oxygen species (ROS) and oxidative stress. In addition, since the introduction of the parasitic nematode Anguillicola crassus in the early 1980s, swimbladder function of most of the European eels is impaired by the infection with this parasite. However, the exact pathways to detoxify ROS and how these pathways are affected by silvering or the infection are still unknown. In swimbladder and muscle tissue from uninfected and infected yellow, and from uninfected and infected silver eels, we measured the level of lipid peroxidation, which increases with ROS stress. To assess the capacity of the ROS defense systems, we analyzed the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione reductase (GR), and determined the concentration of the antioxidant glutathione (GSH + GSSG). In swimbladder tissue, we found increased concentrations of GSH + GSSG as well as higher activities of SOD, GPx and GR, suggesting that SOD and the glutathione cycle are important for ROS detoxification. Comparing swimbladder tissue of uninfected yellow with uninfected silver eels, the concentration of GSH + GSSG and the activity of SOD were higher after silvering, corresponding with lower levels of lipid peroxidation. Whereas in yellow eels the infection with A. crassus had no effect, in silver eels the capacity to cope with ROS was significantly impaired. In muscle tissue, silvering or the infection only affected the activity of SOD but in exactly the same way as in swimbladder tissue. [ABSTRACT FROM AUTHOR]

The stock of European Eel ( Anguilla anguilla L.) has reached an all-time low in 2011. Spawner quality of mature eels in terms of health status and fitness is considered one of the key elements for successful migration and reproduction. Dioxin-like Polychlorinated Biphenyls (dl-PCBs) are known persistent organic pollutants potentially affecting the reproductive capability and health status of eels throughout their entire lifetime. In this study, muscle tissue samples of 192 European eels of all continental life stages from 6 different water bodies and 13 sampling sites were analyzed for contamination with lipophilic dl-PCBs to investigate the potential relevance of the respective habitat in light of eel stock management. Results of this study reveal habitat-dependent and life history stage-related accumulation of targeted PCBs. Sum concentrations of targeted PCBs differed significantly between life stages and inter-habitat variability in dl-PCB levels and -profiles was observed. Among all investigated life stages, migrant silver eels were found to be the most suitable life history stage to represent their particular water system due to habitat dwell-time and their terminal contamination status. With reference to a possible negative impact of dl-PCBs on health and the reproductive capability of eels, it was hypothesized that those growing up in less polluted habitats have a better chance to produce healthy offspring than those growing up in highly polluted habitats. We suggest that the contamination status of water systems is fundamental for the life cycle of eels and needs to be considered in stock management and restocking programs. [ABSTRACT FROM AUTHOR]

Environmental pollution of fish with organic contaminants is a topic of rising attention in Morocco. Polycyclic aromatic hydrocarbons (PAH) are prominent organic contaminants which are rapidly metabolized in fish. Their metabolites are accumulated in the bile fluid and can be used to assess PAH exposure. The two PAH metabolites 1-hydroxypyrene and 1-hydroxyphenanthrene were quantified in European eels ( Anguilla anguilla) from two Moroccan river systems by high-performance liquid chromatography with fluorescence detection. Mean values ranged from 52 to 210 ng/mL 1-hydroxypyrene and from 61 to 73 ng/mL 1-hydroxyphenanthrene. The overall concentrations of PAH metabolites in eel from Morocco appeared moderate compared to eel from European rivers and coastal sites. The present study provides first information on concentrations of PAH metabolites in fish from Morocco. [ABSTRACT FROM AUTHOR]

The European eel Anguilla anguilla has shown decreased recruitment in recent decades. Despite increasing efforts to establish species recovery measures, it is unclear if the decline was caused by reduced numbers of reproductive-stage silver eels reaching the spawning area, low early larval survival, or increased larval mortality during migration to recruitment areas. To determine if larval abundances in the spawning area significantly changed over the past three decades, a plankton trawl sampling survey for anguillid leptocephali was conducted in March and April 2011 in the spawning area of the European eel that was designed to directly compare to collections made in the same way in 1983 and 1985. The catch rates of most anguilliform leptocephali were lower in 2011, possibly because of the slightly smaller plankton trawl used, but the relative abundances of European eel and American eel, Anguilla rostrata, leptocephali were much lower in 2011 than in 1983 and 1985 when compared to catches of other common leptocephali. The leptocephali assemblage was the same in 2011 as in previous years, but small larvae of mesopelagic snipe eels, Nemichthys scolopaceus, which spawn sympatrically with anguillid eels, were less abundant. Temperature fronts in the spawning area were also poorly defined compared to previous years. Although the causes for low anguillid larval abundances in 2011 are unclear, the fact that there are presently fewer European and American eel larvae in the spawning area than during previous time periods indicates that decreased larval abundance and lower eventual recruitment begin within the spawning area. [ABSTRACT FROM AUTHOR]

The stock of the European eel ( Anguilla anguilla L.) continues to decline and has reached a new minimum in 2011. Poor health status of the spawners due to organic contaminants is one of the possible causes for this dramatic situation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants, which are rapidly metabolized in vertebrates. EROD (ethoxyresorufin- O-deethylase) and GST (glutathione- S-transferase) are two enzymes involved in PAH detoxification in fish. In this study, PAH metabolites as well as EROD and GST activity in a large, comprising dataset of more than 260 migratory and pre-migratory eels from five large German river basin districts were used to describe PAH exposure and its metabolism as possible indicators for the habitat quality for eels. Eel from the river Elbe appear to be moderately contaminated with PAH. Highest mean values of PAH metabolites were analysed in fish from the river Rhine. However, the results suggest that contaminants such as PAH are metabolized in the fish and may have contributed to EROD activity in eels caught from the Elbe estuary to 600 km upstream. Since the eel's onset of cessation of feeding is closely linked to maturation and migration, we propose bile pigments as new indicators contributing to identify the proportion of migratory eel, which is crucial information for eel management plans. We showed that PAH metabolites normalized to bile pigments as well as EROD could be used to describe the habitat quality and might be suitable parameters in search for suitable stocking habitats. [ABSTRACT FROM AUTHOR]

Leptocephali of several elopomorph families can reach sizes of 100-300 mm or larger, but it is questionable if these large eel or notacanth larvae are effectively sampled by small-mesh sampling gear in the open ocean because of net avoidance or insufficient fishing effort. A sampling survey in the Sargasso Sea using both an Isaacs-Kidd Midwater Trawl (IKMT) with fine mesh and a large pelagic trawl with large mesh sizes found that fewer species and individual large leptocephali >100 mm were collected by 25 IKMT tows compared to 4 trawl deployments. Net avoidance of the IKMT by the larger leptocephali appeared to occur at least during the day, and the large trawl did not catch any small leptocephali because of the large mesh size. A combination of net avoidance of the IKMT and greater sampling effort of the much larger mouth-opening trawl seems to have resulted in more large leptocephali being collected by the trawl. This indicates that IKMT surveys undersample large leptocephali species and that large trawls do not sample the whole assemblage of leptocephali. To fully understand the biodiversity and abundance of leptocephali in the world's oceans, large fine-mesh sampling gear like the IKMT and very large trawls with smaller mesh will likely be needed. This may be important because leptocephali are probably more abundant in the open ocean than is realized, and their role in the ocean surface layer communities and carbon cycle is not understood. [ABSTRACT FROM AUTHOR]

Much attention has been paid to the molecular phylogeny of holocephalan fishes during recent years, but sampling was very low and not all genera were examined. This study offers an extended sampling of species from all known genera to clarify their phylogeny and to provide an estimate of the time of origin of extant holocephalan taxa. Three mitochondrial genes (cytochrome b, 12S rRNA, and 16S rRNA) were sequenced and analysed using a variety of phylogenetic methods (Bayes, maximum likelihood, and maximum parsimony). Callorhinchidae diverged from Rhinochimaeridae and Chimaeridae about 187 Ma ago. Chimaeridae and Rhinochimaeridae diverged from each other about 159 Ma ago. Within Rhinochimaeridae, Neoharriotta is the sister genus to the closely related Harriotta and Rhinochimaera. Eight species of the family Chimaeridae, belonging to the genera Hydrolagus and Chimaera, were examined. They probably had a common ancestor about 107 Ma ago and appear paraphyletic. These results indicate that the traditional morphological generic definition of the families Rhinochimaeridae and Chimaeridae has to be reinvestigated. [ABSTRACT FROM AUTHOR]

The Antarctic fish fauna is characterized by high endemism and low species diversity with one perciform suborder, the Notothenioidei, dominating the whole species assemblage on the shelves and slopes. Notothenioids diversified in situ through adaptive radiation and show a variety of life history strategies as adults ranging from benthic to pelagic modes. Their larval development is unusually long, lasting from a few months to more than a year, and generally includes a pelagic larval stage. Therefore, the advection of eggs and larvae with ocean currents is a key factor modulating population connectivity. Here, we compare the genetic population structures and gene flow of seven ecologically distinct notothenioid species of the southern Scotia Arc based on nuclear microsatellites and mitochondrial DNA sequences (D-loop/cytochrome b). The seven species belong to the families Nototheniidae ( Gobionotothen gibberifrons, Lepidonotothen squamifrons, Trematomus eulepidotus, T. newnesi) and Channichthyidae ( Chaenocephalus aceratus, Champsocephalus gunnari, Chionodraco rastrospinosus). Our results show low-population differentiation and high gene flow for all investigated species independent of their adult life history strategies. In addition, gene flow is primarily in congruence with the prevailing ocean current system, highlighting the role of larval dispersal in population structuring of notothenioids. [ABSTRACT FROM AUTHOR]

In recent years, thicklip grey mullet Chelon labrosus has shown increasing expansion of its native habitats in the north-eastern Atlantic into northerly adjacent areas including the North Sea and the brackish Baltic Sea. Despite the regular annual and seasonal occurrence of C. labrosus in the western Baltic during the warm months, nothing is known of the origin or whereabouts of the mullet during the cold season. As different possible migration scenarios can be considered, we performed otolith microchemistry analyses on specimens from the western Baltic Sea to identify the origin of this nonindigenous species. Comparison with North Sea samples revealed common habitat preferences and underlined the highly euryhaline nature of C. labrosus in different recently occupied habitats. Occasional fluctuations of Sr/Ca ratio along the growth axis suggest periodical migration between waters of different salinities but did not reveal distinct migration pathways. [ABSTRACT FROM AUTHOR]

Sequence variation in the mitochondrial control region was studied in the Mediterranean rainbow wrasse ( Coris julis), a species with pronounced pelagic larval phase inhabiting the Mediterranean Sea and the adjacent coastal eastern Atlantic Ocean. A total of 309 specimens from 19 sampling sites were analysed with the aim of elucidating patterns of molecular variation between the Atlantic and the Mediterranean as well as within the Mediterranean Sea. Phylogeographic analyses revealed a pronounced structuring into a Mediterranean and an Atlantic group. Samples from a site at the Moroccan Mediterranean coast in the Alboran Sea showed intermediate frequencies of 'Mediterranean' and 'Atlantic' haplotypes. We recognised a departure from molecular neutrality and a star-like genealogy for samples from the Mediterranean Sea, which we propose to have happened due to a recent demographic expansion. The results are discussed in the light of previous studies on molecular variation in fish species between the Atlantic and the Mediterranean and within the Mediterranean. [ABSTRACT FROM AUTHOR]

The present study experimentally tested the influence of water temperature on the inclusion of 15 elements into juvenile European eel ( Anguilla anguilla) otoliths in freshwater. It should be investigated (1) if temperature effects on otolith Sr/Ca might impair the interpretation of migration studies and (2) if the elemental composition of otoliths can be used to reconstruct experienced temperature histories of eels. Therefore, eels were kept under full experimental conditions at three different water temperatures (14 °C, 19 °C and 24 °C) for 105 days. Thereafter, laser ablation inductively coupled mass spectrometry (LA-ICPMS) was conducted on the outer edge of their otoliths. Our analyses revealed significant temperature effects on otolith Na/Ca, Sr/Ca, Mg/Ca, Mn/Ca, Ba/Ca, Zr/Ca and Y/Ca ratios. Variations of Sr/Ca caused by temperature were far below those used to detect eel movements between waters of different salinities and will therefore not affect the interpretation of migration studies. Elemental fingerprints of Sr/Ca, Mg/Ca, Mn/Ca and Ba/Ca ratios resulted in clearly separated groups according to temperature treatments, indicating that changes in water temperature might lead to characteristic changes in otolith element composition. However, the successful application of elemental fingerprints to reconstruct moderate changes of water temperature seems doubtful because the influence of somatic growth on otolith microchemistry still remains unclear, and temperature-induced variations could be overlaid by changes of water element concentrations during growth periods. Nevertheless, our results contribute to the completion of knowledge about factors influencing element incorporation and help to explain variations in element composition of fish otoliths. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Otolith microchemistry is widely used as a tool to track individual migration pathways of diadromous fish under the assumption that the elemental composition of fish otoliths is directly influenced by the physicochemical properties of the surrounding water. Nevertheless, several endogenous factors are reported to affect element incorporation into fish otoliths and might lead to misinterpretations of migration studies. This study experimentally examined the influence of eight different diets on the microchemical composition of European eel ( Anguilla anguilla) otoliths using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Seven natural prey types and one artificial diet were fed during 8 weeks in freshwater circuits. Results show for the first time that food has no significant influence on the incorporation of Na, Sr, Ba, Mg, Mn, Cu and Y into European eel otoliths. This indicates that the incorporation of elements usually chosen for migration studies is not affected by diet and that individual feeding behaviour of A. anguilla will not lead to any misinterpretation of migration pathways. [ABSTRACT FROM AUTHOR]

The family Labridae is a large assemblage of marine fish composed of about 580 species in 82 genera distributed in tropical and temperate marine waters around the world. Several subgroups, currently classified as tribes, have been identified in this large family, yet only a few phylogenetic analyses have been performed on labrid clades. We confirm monophyly of the labrid tribe Labrini and propose a phylogeny of the 23 species of the genera Acantholabrus, Centrolabras, Ctenolabrus, Labrus, Lappanella, Symphodus, Tautoga, and Tautogolabrus occurring in the eastern and western Atlantic and the Mediterranean. We analyzed a 577-bp segment of the mitochondrial 16S rDNA and a 506-bp segment of the mitochondrial control region in 22 species, for a total of up to 1069 bp per species. We used both parsimony and likelihood approaches under a variety of assumptions and models to generate phylogenetic hypotheses. The main features of the molecular phylogeny for the Labrini turned out to be the same for the two algorithms applied. The tree structure is similar to a previous, unpublished morphological phylogeny for a subset of labrine species. Estimated divergence times of the Labrini based on fossils and a molecular clock range from about 15 mya for the deepest splits to less than 1 mya for younger clades. Biogeographic patterns of the Symphodus species group and the genus Labrus are dominated by speciation events driven by the closing and opening of the Mediterranean Sea and periodic glaciation events during the past 1 million years. The Labrini are the only clade in the entire Labridae that exhibit nest-building and broodcare behavior. We use the phylogeny to show that similar broodcare behavior has evolved twice in the labrine fish and discuss scenarios for the evolution of broodcare from the diandric protogynous hermaphroditism found in ancestral labrines and many other wrasses. [ABSTRACT FROM AUTHOR]

Seabreams are among the most valuable fish, not only for small-scale and semiindustrial fisheries but also for aquaculture throughout the Mediterranean. Nevertheless, their phylogenetic relationships are not at all clear. The current taxonomy is based solely on trophic morphology and rests on the assumption that each trophic type evolved only once from a less specialized ancestral condition. We analyzed a 486-bp segment of the mitochondrial 16S rDNA of all 24 seabream species described for the northeastern Atlantic and the Mediterranean to elucidate their generic and subfamily-level relationships. Three major mitochondrial lineages, each comprising species of different feeding strategy and dentition, were found that do not agree with the present taxonomic assignments. Most of the investigated genera were resolved paraphyletically, indicating that the structure and arrangement of oral teeth must have repeatedly evolved from a less specialized ancestral condition. Further, the genus Sparus was resolved as distantly related to the genus Pagrus, in that it was assigned to a different major mitochondrial lineage. Oblada melanura was consistently placed within the Diplodus radiation as sister group to Diplodus puntazzo. Our phylogenetic hypothesis thus suggests multiple independent origins of similar trophic specializations within the Sparidae and indicates that the currently recognized three or four subfamilies need to be redefined. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants (POPs) are monitored regularly in water, sediment, and biota in the Baltic Sea. Lipophilic substances are measured in remarkable concentrations especially in the fatty parts of fish, such as herring (Clupea harengus). However, less lipophilic POPs, e.g. perfluorinated compounds (PFCs), can also be detected. For the first time to our knowledge, this study provides a broad range of contaminant concentrations simultaneously measured in filet, liver, and gonads of both sexes of Baltic herring. We analysed organochlorines, polybrominated diphenyl ethers (PBDEs), and PFCs in mature autumn-spawning individuals and found distinct organ pollutant pattern for all POPs in both sexes. POP concentrations found in the gonads of both sexes indicate that not only females but also males tend to reduce contaminants via reproduction. However, sex-dependent differences could be identified for hexachlorobenzene, PBDEs, and were most remarkable for PFCs. This transfer of contaminants to the gonads in both male and female herring is being underestimated, as it may directly affect the general reproduction success as well as the healthy development of the next generation. Hence, the accumulation of contaminants in the gonads should be considered one possible threat to a healthy wildlife as its achievement is stated by the Baltic Sea Action Plan. Inclusion of a periodic monitoring of POP concentrations in gonads of fish may be an important bioeffect measure to assess the environmental status of biota in the Baltic Sea. [ABSTRACT FROM AUTHOR]