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Species of Artemia are regionally endemic branchiopod crustaceans composed of sexual species and parthenogenetic lineages, and represent an excellent model for studying adaptation and speciation to extreme and heterogeneous hypersaline environments. We tested hypotheses of whether populations from the Tibetan Plateau belong to A. tibetianaAbatzopoulos, Zhang & Sorgeloos,1998 and whether a population from Kazakhstan is a new species, using other Asian species of Artemia as outgroups. We conducted a multitrait phylogenetic study based on the complete mitogenome, mitochondrial (COI, 12S, 16S) and nuclear (microsatellites, ITS1) markers, and a suit of uni- and multivariate morphological traits. Our results led to the discovery of two new species, one from the Tibetan Plateau (Haiyan Lake) in China (Artemia sorgeloosin. sp.) and a second from Kazakhstan (Artemia amatin. sp.). Our analysis demonstrate that A. tibetiana and A. amatin. sp. are monophyletic, whereas A. sorgeloosin. sp., and A. tibetiana are polyphyletic. Evolutionary relationships based on mitochondrial and nSSR markers suggest that A. tibetiana may have arisen from a past hybridization event of a maternal ancestor of A. tibetiana with A. sorgeloosin. sp. or its ancestor. We present the complete mitogenome of A. tibetiana, A. amatin. sp., and A. sorgeloosin. sp. We also provide a novel taxonomic identification key based on morphology, emphasizing the phenotype as a necessary component of the species concept., This study has been supported by the Major Science and Technology Projects in Hainan Province (China) in 2019 (ZDKJ2019011-03-02).

Ecosystems of inland saline waters play a significant role in the biosphere and human life. Various articles of this Special Issue are devoted to a wide range of issues of their study and management. This introductory article gives a general overview of the types of inland waters on the planet, as well as the features of their ecosystems, reflected in 18 articles of this Special Issue. Attention is also paid to modern problems of conservation and integrated sustainable use of aquatic ecosystems in a changing climate and increasing anthropogenic pressure on water bodies.

The brine shrimp Artemia is a highly required, convenient and cost-effective live food used in fish and shellfish larviculture. Its cysts, originating from a limited number of inland salt lakes, are traded worldwide. Over the past decades, Artemia pond production in solar saltworks, integrated with salt production, has emerged as an alternative to cope with possible cyst shortages and high prices on the international market and as a tool to fulfill local cyst and Artemia biomass demands associated with local and regional aquaculture developments. This article reviews the principles of Artemia pond production and how it is practiced in terms of general management. It also describes the distinctive features that have evolved in various countries, due to geographical, environmental and socio-economic characteristics and the local aquaculture context. It highlights the lessons that may be learnt from previous successes and failures for new areas where the technique may be introduced. The principles of Artemia pond production are also discussed in the light of global and local Artemia biodiversity, as its protection is key to support the sustainability of the aquaculture industry. This review pioneers in bringing this information, much of which was restricted to grey literature until now, under the attention of the international scientific audience. Future research and development should focus on continued proper management to secure cyst production and to maximize cyst quantities. Moreover, using the information provided by the Artemia genome will allow as well to strive for improved cyst quality, by producing strains with specific market characteristics.

Further biogeographical studies of parasites are vital to improve our understanding of biodiversity distribution and predict the impacts of global change. Hypersaline lakes are good laboratories to investigate the avian cestode abundance and species diversity given the abundance of hosts (waterbirds and Artemia) and their broad latitudinal distribution. We analysed cestode infection in brine shrimp Artemia franciscana in northern (Atacama) and central Chile and compared them to results from A. persimilis in southern Chile (Patagonia). Thus, we covered a broad latitudinal gradient from 23° to 53° S. Five cestode taxa including two species of the genus Flamingolepis, Gynandrotaenia stammeri, Eurycestus avoceti, and Fuhrmannolepis averini were recorded from A. franciscana in Atacama lagoons (prevalence = 4.1%). In contrast, no cestode infection was detected in central Chile, likely because they are temporary wetlands. Parasites of flamingos and shorebirds were associated with Atacama lagoons (arid and higher salinity), while Confluaria podicipina and Fimbriarioides sp. (parasites of grebes and ducks, respectively) were dominant in Patagonian lagoons (sub-antarctic and of lower salinity). These differences mirror changes in the relative abundance of the respective final hosts. The flamingo parasite Flamingolepis sp. 1 was the most prevalent and abundant cestode in Atacama, where it was recorded only in autumn. Seasonality and habitat effects (especially abundance and phenology of different bird species) appear to override any latitudinal trends in the prevalence, diversity, and distribution of cestodes. Cestode prevalence was higher in larger wetlands but was not related to the sex of either intermediate host. We recorded a greater taxonomic richness at the cestode family level in Atacama, but a greater dominance of a single family of avian hosts (the flamingos). Ours is the first spatio–temporal study of Artemia cestodes at local and regional scales in the southern hemisphere.

The Chilean north Patagonian inland waters are characterized by their low mineral concentrations. In their original status, many of these ecosystems have native vegetation in their surrounding drainage basins, but in the last decades the native vegetation was replaced by agricultural, urban, and industrial zones, with as a result of these human alterations that those aquatic communities changed. The aim of the present study was to make a literature review about the ecological role of crustaceans in Chilean north Patagonian lakes and rivers. The literature mentioned the presence of amphipods (Hyalella), crayfishes (Samastacus spinifrons), and freshwater crabs (genus Aegla), and many of these species hold a conservation risk due to the consequences of habitat damage and/or their high endemism. These crustaceans are important for the degradation of particulate organic matter originating from the surrounding vegetation, and are prey for native and introduced salmonid fishes. Similar patterns had already been observed for Argentinean Patagonian rivers.

The palm ruff, Seriolella violacea (Cojinoba), is a potential new species for Chilean aquaculture. To approach Cojinoba larviculture, an experimental Artemia enrichment emulsion, containing docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) = 2.5, supplemented with vitamin E, astaxanthin, and β-glucan, was evaluated in both Artemia and Cojinoba larvae, 30–50 d.a.h. This study tested an experimental enrichment emulsion versus a commercial emulsion, with an integral approach of multicompound emulsions. After 23 h enrichment, experimental emulsion (EE)-enriched nauplii reached DHA and EPA concentrations of 23.8 and 18.7 mg/g dry weight (dwt), respectively, while in Cojinoba larvae they were 18.4 and 19.7 mg/g dwt. Control emulsion (CE)-enriched nauplii exhibited lower DHA and EPA (6.1 and 7.7 mg/g dwt), while only DHA decreased in the control larvae (12.6 mg/g dwt). Vitamin E was higher in EE-enriched nauplii (29.2 mg/100 g dwt) than in the control (8.4 mg/100 g dwt). Larvae fed EE-enriched Artemia exhibited 8% increase in survival and 19% in growth compared with the control. Astaxanthin was detected only in larvae fed EE-enriched nauplii. The tumor necrosis factor-α concentration was not significantly different between larvae fed EE- and CE-enriched nauplii. EE looks promising as an Artemia enrichment and experimental diet to assess palm ruff larval requirements, and has a positive impact on fish larvae performance.

Laguna de los Cisnes (53°15’S) is a remote and unusual salty lagoon located in the Chilean Patagonia, declared natural monument to protect bird diversity in the area, which could also serve as a natural laboratory to monitor climate change. This study reports basic water, sediment and plankton characteristics observed during a summer (December) sampling, when the lagoon was hypersaline (51 g L -1 ), cold (9°C) and eutrophic, according to the high concentrations of phosphorous (0.30 ± 0.73 mg L -1 ), nitrate (0.66 ± 0.14 mg L -1 ) and chlorophyll-a (44.25 ± 2.52 µg L -1 ). The microalgae Spirogyra sp. and the micro-crustacean Artemia are predominating plankton. Results are discussed in the context of the climatic conditions affecting this lagoon year-round. Normal 0 21 false false false ES-CL X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}

Biological invasions create complex eco- logical and societal issues worldwide. Most of the knowledge about invasions comes only from success- ful invaders, but less is known about which processes determine the differential success of invasions. In this review, we develop a framework to identify the main dimensions driving the success and failure of invaders, including human influences, characteristics of the invader, and biotic interactions. We apply this frame- work by contrasting hypotheses and available evi- dence to explain variability in invasion success for 12 salmonids introduced to Chile. The success of On- corhynchus mykiss and Salmo trutta seems to be influenced by a context-specific combination of their phenotypic plasticity, low ecosystem resistance, and propagule pressure. These well-established invaders may limit the success of subsequently introduced salmonids, with the possible exception of O. tshawyts- cha, which has a short freshwater residency and limited spatial overlap with trout. Although propagule pressure is high for O. kisutch and S. salar due to their intensive use in aquaculture, their lack of success in Chile may be explained by environmental resistance, including earlier spawning times than in their native ranges, and interactions with previously established and resident Rainbow Trout. Other salmonids have also failed to establish, and they exhibit a suite of ecological traits, environmental resistance, and lim- ited propagule pressure that are variably associated with their lack of success. Collectively, understanding

Zooplankton diversity in shallow salt lakes of the Andean countries in South America is low and distribution is highly dependent on salinity, which varies from moderate to high. At salinities lower than 90 g/l, the halophilic copepod Boeckella poopoensis (Marsh, 1906) predominates, whereas above that level the anostracan Artemia franciscana (Kellogg, 1912) is the exclusive component of the habitat. This constitutes, however, fragmentary information only. A review of the available literature for Andean saline lakes in Bolivia, Chile, and Peru, confirms that presence and distribution of both species is significantly driven by salinity levels. The results of a species co-occurrence null model analysis, indicates that species associations are not random, and these results are supported by the correlation analysis, which indicates a significant, inverse correlation between species number and salinity, and a significant direct relation of species number with surface of the habitat. The low species diversity characteristically seen in these habitats and their dependence on salinity changes effectuated by weather conditions, provide a good model-system for monitoring weather change. La diversidad del zooplankton en lagos salinos poco profundos de Sudamerica es baja y su distribucion depende altamente de la salinidad, la cual varia de moderada a alta. A salinidades menores a 90 g/l predomina el copepodo halofilico Boeckella poopoensis (Marsh, 1906), mientras que a salinidades superiores a ese nivel, el anostraco Artemia franciscana (Kellogg, 1912) es el componente exclusivo de los habitats. Esto constituye sin embargo una informacion parcial. En una revision de la literatura disponible para lagos salinos Andinos en Bolivia, Chile y Peru se confirma que la presencia y distribucion de ambas especies esta significativamente regulada por el nivel de la salinidad. Los resultados del modelo nulo de co-ocurrencia de especies indican que las asociaciones de especies no son aleatorias, y estos resultados estan respaldados por el analisis de correlacion, el cual indica una relacion inversa significativa entre numero de especies con salinidad, y hubo relaciones directas significativas entre numero de especies con la superficie del habitat. El bajo numero de especies que es caracteristico de estos habitats y su dependencia con los cambios de salinidad efectuado por las condiciones climaticas provee un buen modelo de sistema de monitoreo de cambios climaticos.

Previous researches have established that the swim speed of some microcrustaceans is influenced by chemical compounds emitted by conspecifics. We examined the hypothesis that cuticular compounds present on the body surface of A. franciscana, the most widespread member of Artemia genus, play a role in the swim speed of conspecific males. The movements (swim) of one male confronted to a sponge soaked with female or male cuticular extract, were recorded during 30 minutes and the swim speed was determined using a behavioral tracking software (Ethovision 3.1, Noldus Technologies). As a control, the movements of one male confronted to a sponge soaked with salty water or with a mixture of the solvents used in the extraction (chloroform-methanol), was recorded. The results showed that cuticular compounds from either female or male increase 1.5 (ca.) times the swim speed of males in comparison with the controls treatments salty water and the solvents. There was no a significant difference between the controls (salty water and chloroform-methanol). Chemical characterization was developed by sterification of the cuticular extracts and analyses by GC-FID and GC-MS. Four saturated fatty acid (myristic acid, palmitic acid, estearic acid, arachidic acid) and five insaturated fatty acids (oleic acid, linoleic acid, linoleic acid 3n3, cis-11-eicosanoic acid, euric acid) were identified. Myristic acid was found in female cuticular extract, but not in male cuticular extract. Results suggest that chemical compounds present in the cuticular surface of A. franciscana females could have an important role in the intra-specific recognition in this specie.

Se realizaron dos experimentos conductuales para evaluar que A. franciscana muestra patrones de cortejo especificos, que en parte, serian gobernados por semioquimicos liberados por hembras. El etograma del cortejo, construido a partir de la grabacion individual de 30 parejas adultas virgenes (1 hembra v/s 1 macho) durante 1 hora, revelo que los machos mostraron cuatro patrones de actividad independientes: 1) acercamiento y toque, 2) nado en retroceso, 3) intento de monta, y 4) exito de monta. El analisis de las transiciones entre los patrones observados sugirio dos maneras de conseguir una monta exitosa, en ambas el patron acercamiento y toque fue fundamental. La primera transicion consistio en que una vez que los machos se acercan y tocan a las hembras, intentan montar a las hembras (27% de probabilidad de ocurrencia), pero si esto no ocurre los machos comienzan nuevamente a acercarse y tocar a las hembra (23% de probabilidad de ocurrencia) para finalmente lograr una monta exitosa (19% de probabilidad de ocurrencia). La ruta alternativa es mediante la aproximacion y toque para luego desarrollar el nado en retroceso (7% de probabilidad de ocurrencia) y montaje exitoso (5% de probabilidad de ocurrencia). El rol de los semioquimicos liberados por hembras fue evaluado mediante el uso de la solucion polar (SP) obtenida desde agua acondicionada con 40 hembras virgenes. Machos virgenes fueron empapados con SP para obtener pseudo hembras. Luego, se enfrentaron 1 pseudo hembra, 1 hembra, 1 macho control a ya sea 1 o 5 machos. En todos los casos, la conducta fue registrada durante 1 hora (n=10), y se analizaron las frecuencia de ocurrencia de cada uno de los patrones de cortejo. Los resultados mas importantes mostraron que: 1) la hembra virgen y pseudo hembra elicito la misma frecuencia de respuesta en 1 macho en los cuatro patrones de cortejo (P˃0,05); b) hembras virgenes y pseudo hembras obtuvieron la misma respuesta cuando se evaluaron contra 5 machos en acercamiento y toque, nado en retroceso e intento de monta (P˃0,05). El hecho que en todo los casos el macho control siempre elicito el menor valor de frecuencia en cada patron de cortejo sugiere el posible rol de semioquimicos sexuales en la conducta de cortejo de A. franciscana. La combinacion de senales quimicas y conductuales sugieren un elaborado reconocimiento de pre-cortejo.

Hatchery-reared Argopecten purpuratus larvae were fed a Dunaliella tertiolecta-diet (DUN-diet) supplemented with 0%, 20% or 40% of a highly unsaturated fatty acid (HUFA) lipid emulsion (ICES Reference Emulsions), rich in docosahexaenoic acid (22:6n−3, DHA) and eicosapentaenoic acid (20:5n−3, EPA). A standard diet (ST-diet), consisting of a mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile was used as a positive control. The supplementation of 20% and 40% HUFA-emulsion to the DUN-diet led to a significantly better daily growth rate (136–177% as compared to DUN-diet) and a higher percentage of eyed-pediveliger larvae in comparison with the non-supplemented DUN-diet. Practically no eyed-larvae were present when fed with D. tertiolecta only, whereas 17% of the larvae developed an eyespot when fed a 20% HUFA-supplement. An increase of the lipid supplement from 20% to 40% further improved the larval performance, although the difference was not significant and less than compared with the changes between the non-supplemented DUN-diet and the DUN+20%-diet. The poor performance of larvae that received D. tertiolecta only was attributed to the depletion of the lipid reserves in the triglyceride fraction and possibly to the very low levels of saturated fatty acids 14:0 and 16:0, rather than to the low levels of EPA and DHA (in absolute terms). Limited biosynthesis of DHA from EPA as a precursor molecule is proposed. Despite similar relative and absolute fatty acid levels of DHA and EPA in larvae that received the ST-diet and the DUN+40%HUFA-diet, the former performed significantly better. Other factors such as the arachidonic acid (20:4n−6) content and the n−3/n−6 ratio are suggested to play a determining role.

The impact of dietary fatty acids on the fatty acid composition and content in different organs (digestive gland, adductor muscle and male and female gonad) of Argopecten purpuratus was evaluated during the process of gonad maturation under controlled laboratory conditions. A mixed algal diet of Isochrysis galbana (clone T-Iso), Pavlova lutheri , Chaetoceros gracilis and Tetraselmis suecica was either fed alone (Al) or supplemented with 50% lipids (expressed as % of the algal dry weight (DW)) using an emulsion rich in 22:6 n −3 (Al+EmDHA) or an emulsion rich in 20:5 n −3 (Al+EmEPA). Results showed the algal diet having the greatest impact on the fatty acid composition (mainly an increase of 18:1 n −9, 18:2 n −6; 18:3 n −3 and a decrease of 20:5 n −3) of the digestive gland and female gonad, moderate in the male gonad while the fatty acid composition of the adductor muscle was hardly affected. Our data indicated that 16:1 n −7 and 18:1 n −9 were partially elongated to 18:1 n −7 and 20:1 n −9, respectively. The supplementation of the algal diet with EmDHA or EmEPA (which contained 45% and 19% 22:6 n −3, respectively) increased significantly the concentration of 22:6 n −3 (mg g −1 DW) in the digestive gland, female gonad and male gonad with 78%, 57% and 51%, respectively, for (Al+EmDHA)-fed scallops and 18%, 33% and 19%, respectively, for (Al+EmEPA)-fed scallops, while the 22:6 n −3 concentration in the adductor muscle was not affected. Broodstock conditioning was associated with a significant increase of the lipid content in the female and to a lesser extent in the male gonad. The significant increase (as compared to the initial sample) of the 22:6 n −3 concentration in the digestive gland, female gonad and eggs of A. purpuratus fed 22:6 n −3-rich lipid illustrated that recently ingested fatty acids did significantly contribute to the lipid accumulation process in the maturing female gonad. The similarities between the fatty acid composition of the female gonad and digestive gland suggest that lipids were transferred from the lipid-rich digestive gland to the female gonad.

The endemic marine gastropod Chorus giganteus represents a significant part of the benthic biomass subject to heavy exploitation by artisanal fisheries in Chile. Overexploitation has restricted its formerly wide distribution to few sites, and this study deals with the electrophoretic characterisation of three populations from the two main fishing grounds in the south coast of Chile (37–39°S). While frequency of polymorphic loci is high (41–50%), the observed heterozygosity is low (between 0.028 and 0.040) though within the range for molluscs. Heterogeneity in allelic frequencies at six polymorphic loci suggests potential for population substructuring. All these loci showed significant heterozygote deficits. The calculated number of migrants per generation ( N e m =4.75), based on a Wright’s F ST mean value of 0.05, accounts for low gene flow among populations in line with breeding behaviour (locally restricted). These preliminary results set a baseline for further evaluation of the intraspecific genetic diversity of an overexploited mollusc with low larval dispersal ability, and hence limited ability for colonisation. Since basic culture techniques are not yet available, genetic monitoring of this species throughout its entire distribution should be promoted for proper management and/or conservation of the species gene pool, in addition to current regulations aimed at restricting further exploitation.

An Artemia population from a site recently described in Chile and located in a semi-arid and humid hydrographical zone (Torres del Paine National Park), was electrophoretically characterized and cross-bred (followed through F 3) to reference samples of A. franciscana (San Francisco Bay, California, U.S.A.) and A. persimilis (Buenos Aires, Argentina), which are the species most likely to be found in Chile. The population exhibited high levels of genetic variability as judged by the percentage of polymorphic loci (P=53.3), mean number of alleles per locus (n=2.2) and mean heterozygosity ( $$\bar H$$ =0.176). Based on the analysis of 15 loci it seems to be closer to A. persimilis (D Nei=0.211) than to A. franciscana (D=0.591). Laboratory cross-fertility tests do not suggest barriers to gene flow or infertility in accordance with eletrophoretic results (genetic distance values or population-specific alleles), though offspring quality tended to be biased toward the production of cysts rather than nauplii, most obviously in F33, which may be an indication of post-zygotic reproductive isolation.

An allozyme survey was conducted in three naturalized populations of rainbow trout, Oncorhynchus mykiss (Walbaum), from rivers in two Andean lakes of southern Chile. The analysis was based on 32 presumed loci, 10 of which were variable, and revealed that the mean percentage of polymorphic loci (P= 21.8%; range = 15.6-28.1%), the mean number of alleles per locus (n=1.26; range = 1.2-1.3) and the mean observed heterozygosity (HO=7.0%; range = 6.0-8.2%) are high, although within the range reported for rainbow trout. Although the mean genetic distance between the samples was low (D = 0.003), and only 5.2% of the total observed genetic variation can be accounted by interpopulation differences (FST= 0.052), eight out of 10 polymorphic loci exhibited significant allelic heterogeneity. Some loci, notably EST-1*, IDHP-3,4*, MEP-1* and PGM-1*, showed considerable discriminatory capacity among the samples. Rainbow trout has a longer history in Chilean waters since salmonid introduction started earlier this century. Under current intensive farming practices, the preliminary information provided in the present paper is likely to be helpful in setting up a baseline for further characterization and/or monitoring of naturalized populations.

In order to enhance genomic resources for the brine shrimp Artemia franciscana, RNA-Seq analysis was conducted for adult females and males. Through de novo assembly, 36,896 high quality contigs were obtained, of which 13,749 sequences were annotated with arthropod sequences. Just 4.5% matched against previously reported sequences for Artemia spp. Additionally, different transcriptional patterns between males and females were found, evidencing sex-related transcriptional responses. Furthermore, 221 and 534 putative SNPs were identified exclusively in males and females, respectively. These results will build the foundation for further genomic studies in A. franciscana.

The electrophoretic characterization of an Artemia population from a saline lake of the Chilean Andes with unusual ecological features (Salar de Atacama, 23° 30′ S; 68° 10′ W) was carried out with the aim of comparing its genetic variation with, and genetic similarity to, representative populations of A. persimilis (Buenos Aires, Argentina) and A. franciscana (San Francisco Bay, USA). Based on the analysis of 22 loci it is concluded that the Chilean population and that from San Francisco are conspecific (D = 0.144), while the Chilean strain and A. persimilis are congeneric species (D = 1.171), differing in more than 40% of the loci. Parameters measuring genetic variation (e.g., percentage of loci polymorphic, mean number of alleles per locus, mean heterozygosity per locus) demonstrate that values for the Chilean Artemia (50.0, 1.68, 0.126, respectively) are within the range for bisexual Artemia in general and A. franciscana in particular.

The impact of supplementing lipid emulsions rich in eicosapentaenoic acid (EmEPA), docosahexaenoic acid (EmDHA) or saturated fatty acids (EmCOCO) to a standard algal diet [3:1 mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile, St-diet] on Argopecten purpuratus broodstock was evaluated. Broodstock fecundity was compared as well as the egg quality in terms of lipid content, fatty acid composition and lipid class distribution. Fecundity was defined as the number of eggs released in the spawning process, since spawning was virtually complete. Results indicated that the total lipid content of the eggs of A. purpuratus was diet independent. A greater energy reserve was spent on a larger number of oocytes and not on bigger sized oocytes with a higher lipid content. The lipids supplied through the emulsions were at least partially allocated to the eggs, demonstrating that the fatty acid composition of the eggs could be manipulated, especially the neutral lipid fraction. Levels of EPA changed more rapidly than DHA levels, supporting the observation that they fulfilled an energetic and structural role, respectively. The St-diet supplemented with 50%EmCOCO resulted in a significantly higher fecundity compared to the algal diet supplemented with 25%EmEPA + 25%EmDHA and the non-supplemented algal diet. It would seem that saturated fatty acids (SAFA) were more easily or preferentially incorporated in the female gonads of A. purpuratus. The relative content of SAFA and 18:2( n-6) in these eggs rose significantly. The relative content of the highly unsaturated fatty acids, EPA and DHA, on the other hand was substantially lower in the neutral lipid fraction, but hardly affected in the polar lipid fraction. It appeared that the maintenance of an adequate DHA/EPA ratio (approximately 1.2) was more important than the absolute levels of the two fatty acids, as long as a threshold value was reached.

A preliminary biometric and ecologic database for the brine shrimp Artemia from Mexico and Chile is presented. The area abounds in small and seasonal ponds and large inland lakes, the latter mainly located in Mexico, although relatively large and isolated lakes are found in complex hydrological settings in pre-high plateau areas of Chile. This paper summarizes research efforts aimed at the localization, characterization, and evaluation of the aquaculture potential of Artemia populations in Mexico and Chile, which exhibit great habitat diversity (ponds, salterns, coastal lagoons, sea arms, coastal and inland lakes), contrasting weather conditions and different levels of isolation and human intervention. This study covered locations between 29° north latitude (Baja California, Mexico) to 50° south latitude (Puerto Natales, Chile). Biological characteristics considered are species name, reproductive mode, cyst diameter, chorion thickness, and nauplius length, whereas ecological data include pond size, pH, salinity, temperature, and water ionic composition. Artemia franciscana is the only species found in Mexico, it exists together with A. persimilis in Chile, though separated geographically. Ecological differences in habitat exist between both regions but also within countries, a pattern particularly clear with regard to water composition. Surprisingly, a Mexican (Cuatro Cienegas, A. franciscana) and a Chilean location (Torres del Paine, A. persimilis) share habitat characteristics, at least for the period when data were collected. The discriminat analysis for cyst diameter and nauplius length shows that Artemia from only one location match in cyst diameter with those from San Francisco Bay (SFB) (Point Lobos), and one (Marquez) is far apart from SFB and all the others. The Chilean locations (Pampilla, Cejar, Cahuil, Llamara, Yape) share cyst diameter, but tend to differ from SFB. The remaining Mexican locations (Juchitan, Ohuira, Yavaros) are well separated from all the others. With regard to nauplii length, populations tend to distribute in a relatively random manner, being Marquez the location differing the most in cyst diameter from SFB. This database will contribute to the knowledge of radiation centers and serves as a baseline for further biogeographic studies, population characterization, management, and monitoring of Artemia biodiversity. Likewise, the impact of colonization and translocations for aquaculture purposes can be better assessed with a baseline for reference. Mexico and Chile exemplify the need to increase and further integrate regional information to tackle fundamental problems underlying practical utilization of Artemia.

Biodiversity can be measured at different hierarchical levels, from genetic diversity within species to diversity of ecosystems, though policy-makers tend to use species richness. The 2010 goal of reducing biodiversity loss, agreed by the subscribers to the Convention on Biological Diversity, requires simple and reliable protocols to evaluate biodiversity at any level in a given ecosystem. Stakeholders, particularly policy makers, need to understand how ecosystem components interact to produce social and economic benefits on the long run, whilst scientists are expected to fulfil this demand by testing and modelling ideally simple (low diversity) ecosystems, and by monitoring key species. This work emphasizes the unique opportunity offered by inland, isolated salt lakes and the brine shrimp Artemia, an example of biodiversity contained at the intra-specific level, as simple models to understand and monitor biodiversity, as well as to assess its predicted positive association with ecosystem stability. In addition to having well identified species and strains and even clones, that allow to test reproductive effects (sexual versus asexual), Artemia benefits from the possibility to set up experimental testing at both laboratory scale and outdoor pond systems, for which a comprehensive cyst bank with sufficient amount of samples from all over the world is available.