Exploring the Potential of Icelandic Seaweeds Extracts Produced by Aqueous Pulsed Electric Fields-Assisted Extraction for Cosmetic Applications.

A growing concern for overall health is driving a global market of natural ingredients not only in the food industry but also in the cosmetic field. In this study, a screening on potential cosmetic applications of aqueous extracts from three Icelandic seaweeds produced by pulsed electric fields (PEF) was performed. Produced extracts by PEF from Ulva lactuca, Alaria esculenta and Palmaria palmata were compared with the traditional hot water extraction in terms of polyphenol, flavonoid and carbohydrate content. Moreover, antioxidant properties and enzymatic inhibitory activities were evaluated by using in vitro assays. PEF exhibited similar results to the traditional method, showing several advantages such as its non-thermal nature and shorter extraction time. Amongst the three Icelandic species, Alaria esculenta showed the highest content of phenolic (mean value 8869.7 µg GAE/g dw) and flavonoid (mean value 12,098.7 µg QE/g dw) compounds, also exhibiting the highest antioxidant capacities. Moreover, Alaria esculenta extracts exhibited excellent anti-enzymatic activities (76.9, 72.8, 93.0 and 100% for collagenase, elastase, tyrosinase and hyaluronidase, respectively) for their use in skin whitening and anti-aging products. Thus, our preliminary study suggests that Icelandic Alaria esculenta-based extracts produced by PEF could be used as potential ingredients for natural cosmetic and cosmeceutical formulations.

Diet and feeding strategy of Northeast Atlantic mackerel (Scombrus scomber) in Icelandic waters.

Predator-prey relations, as well as the trophic ecology of highly migratory marine species, is important to understand their impact on the ecosystem. Conventional methods were used to study the diet composition and feeding strategy of the Northeast Atlantic mackerel (Scombrus scomber), during their summer feeding migration to Icelandic waters in 2009-2014. In addition, generalised additive modelling (GAM) was used to determine which biological and environmental factors contribute to the variation of their stomach weight in the years 2011-2014. From the dietary analysis, we found that calanoid copepods (especially Calanus finmarchicus) were the most important contributor to the overall diet of mackerel in the years studied. Although in some years and areas, they also preyed heavily on larger prey items such as euphausiids, amphipods and megalopa larvae of crab and shrimp. The GAM showed that temperature and the time the day of sampling were significant explanatory variables for the stomach weight, while zooplankton biomass did not seem to have much influence. The Northeast Atlantic mackerel are ferocious feeders upon copepods, as well as exhibiting an overall opportunistic feeding strategy. During their feeding migration in Icelandic waters, they were found to feed on the most dominant species available to them.

Distribution, maturity and population structure of Meganyctiphanes norvegica and Thysanoessa inermis around Iceland in spring.

This study aims to explain the distribution, maturity and population structure of Meganyctiphanes norvegica and Thysanoessa inermis in springtime in relation to main hydrographic regions around Iceland: Atlantic in the southwest, Atlantic-Arctic mixture in the north and Arctic in the east. Krill were collected 14-29 May 2013 using a macrozooplankton trawl. Biomass of both species combined was significantly higher in the southwest than in north and east. M. norvegica clearly dominated in Atlantic waters, whereas T. inermis was more evenly distributed around the island, while the highest values were also observed in the southwest for this species. Simple linear regressions showed that the abundance of M. norvegica was positively related to temperature, salinity and phytoplankton concentration, while the abundance of T. inermis was negatively related to bathymetry. Multiple linear regression analyses did not add to this information of a positive relationship between abundance and temperature for M. norvegica, while T. inermis was shown to be negatively related to both temperature and bathymetry. During the latter half of May, the main spawning of both species was confined to the regions off the southwest coast. Sex ratio (males/females) of M. norvegica was higher in the southwest than in the north and east, whereas T. inermis showed a similar sex ratio all around the island. In all regions, M. norvegica appears to have a lifespan of 2 years while T. inermis of 1 year in the southwest and possibly 2 years in north and east.

Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters.

The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15-16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1-5 m into the water column from the bottom at an average vertical swimming speed of 0.20-0.25 m s(-1) and maintained an average spacing of 1.0-1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

Evidence of segregated spawning in a single marine fish stock: sympatric divergence of ecotypes in Icelandic cod?

There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ≥1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes.

Historical changes in genotypic frequencies at the Pantophysin locus in Atlantic cod (Gadus morhua) in Icelandic waters: evidence of fisheries-induced selection?

The intense fishing mortality imposed on Atlantic cod in Icelandic waters during recent decades has resulted in marked changes in stock abundance, as well as in age and size composition. Using a molecular marker known to be under selection (Pan I) along with a suite of six neutral microsatellite loci, we analysed an archived data set and revealed evidence of distinct temporal changes in the frequencies of genotypes at the Pan I locus among spawning Icelandic cod, collected between 1948 and 2002, a period characterized by high fishing pressure. Concurrently, temporal stability in the composition of the microsatellite loci was established within the same data set. The frequency of the Pan I(BB) genotype decreased over a period of six decades, concomitant with considerable spatial and technical changes in fishing effort that resulted in the disappearance of older individuals from the fishable stock. Consequently, these changes have likely led to a change in the genotype frequencies at this locus in the spawning stock of Icelandic cod. The study highlights the value of molecular genetic approaches that combine functional and neutral markers examined in the same set of individuals for investigations of the selective effects of harvesting and reiterates the need for an evolutionary dimension to fisheries management.

Are vertical behaviour patterns related to the pantophysin locus in the Atlantic cod (Gadus morhua L.)?

Throughout their geographic distribution, marine fish species often form subpopulations with limited connectivity, among which individuals display a variety of migratory behaviours. Fish behaviour experiments using Data Storage Tags (DSTs) have been useful to define the natural movement of individuals. In Icelandic waters, such experiments have indicated the presence of two distinct behaviour types of the Atlantic cod Gadus morhua, related to vertical migrations and habitat choice in feeding migrations. Some individuals have been shown to stay most of the time in shallow waters characterised by the seasonal trend in temperature for the shelf waters, while other migrate to deeper and colder waters where most of them forage in temperature fronts characterized by highly variable temperatures. The analysis of the pantophysin locus (Pan I) of the same individuals revealed that individuals carrying the Pan I AA genotype are likely to display a shallow water feeding migrations while individuals carrying the Pan I BB genotype preferred deeper waters and forage near thermal fronts. The heterozygote exhibited both type of behaviours. This study therefore suggests that further research need to be done on the pantophysin locus and its potential effects on cod phenotypes to assess the potential relationship between this locus and the behavioural types described.