Ictiotoxismo por consumo de barracuda (Sphyraena barracuda) y morena manchada (Gymnothorax moringa) en la comunidad de pescadores artesanales de Tasajera, Caribe colombiano

An icthyotoxism event was studied in the Tasajera fishermen’s community, department of Magdalena. The ciguatera intoxication was diagnosed to 7 individuals whose ages were ranging between 17 and 53 years (63,4 %), with symptoms of vomit (100 %), muscular pain in low members (71,4 %), abdominal spasms (85,7 %), diarrhea (100 %), numbness and tingling of face, hands, feet (85,7 %), sickness (100 %), and cutaneous outbreak (14,2 %), the symptoms in the majority of the cases disappeared in a space from 8 to 12 days. The consumption of the barracuda (Sphyraena barracuda) spotted moray (Gymnothorax moringa) meat was determined as principal source of the ciguatera event.Se estudió un evento de ictiotoxismo en la comunidad de pescadores de la población de Tasajera, departamento del Magdalena. La intoxicación por ciguatera fue diagnosticada a 7 individuos cuyas edades oscilaban entre los 17 y 53 años (63,4% de rango de edades de los pescadores del sector), con síntomas de vómito (100%), dolor muscular en miembros inferiores (71,4%), espasmos abdominales (85,7%), diarrea (100%), entumecimiento y hormigueo de cara, manos, pies (85,7%), mareo (100%), y brote cutáneo (14,2%), los síntomas en la mayoría de los casos desaparecieron en un lapso de 8 a 12 días. Se determinó como causa principal del evento de ciguatera el consumo de carne de barracuda (Sphyraena barracuda) y morena (Gymnothorax moringa). (Duazary 2007; 2: 160 - 167

Functional insights into the testis transcriptome of the edible sea urchin Loxechinus albus

© The Author(s) 2016. The edible sea urchin Loxechinus albus (Molina, 1782) is a keystone species in the littoral benthic systems of the Pacific coast of South America. The international demand for high-quality gonads of this echinoderm has led to an extensive exploitation and decline of its natural populations. Consequently, a more thorough understanding of L. albus gonad development and gametogenesis could provide valuable resources for aquaculture applications, management, conservation and studies about the evolution of functional and structural pathways that underlie the reproductive toolkit of marine invertebrates. Using a high-throughput sequencing technology, we explored the male gonad transcriptome of this highly fecund sea urchin. Through a de novo assembly approach we obtained 42,530 transcripts of which 15,544 (36.6%) had significant alignments to known proteins in public databases. From these transcripts, approximately 73% were functionally annotated allowing the identification of several candidate genes that are likely to play a central role in developmental processes, nutrient reservoir activity, s exual reproduction, gamete generation, meiosis, sex differentiation, sperm motility, male courtship behavior and fertilization. Additionally, comparisons with the male gonad transcriptomes of other echinoderms revealed several conserved orthologous genes, suggesting that similar functional and structural pathways underlie the reproductive development in this group and other marine invertebrates.Link_to_subscribed_fulltex

Evaluación financiera y ambiental de una piscicultura de pargo rayado Lutjanus synagris en el Caribe colombiano

With the aim of evaluate and determine the economic and environmental factibility and the viability of the  production and comercialization of the lane snapper (Lutjanus synagris), a Cost-Benefit, Net Utility, Equivalent  Uniform Periodic Value, and Internal Return Rate (IRR) financial analysis were made involving variables  associated to the culture in floating cages or land ponds, diets and mechanisms of marketing. According to  the financial evaluation criteria, the project would generate an additional wealth of 39.5%. Cost-Benefit ratio  showed that investment would be recovered, obtaining an additional 65% for each monetary unit invested.  The payback period of investment is 7 years and the IIR would exceed the discount rate of the project, which  is 18.95%,  indicating, as well as the others assessment criteria, that this project is favorable when dealing with financing and a 5% increase on the price per unit in smoked fish of 250 g in the model associated with  floating cages culture. The Leopold matrix allowed to identify that the main environmental impacts associated  with the project are involved in the construction phase of the facilities and the land pondsCon el fin de evaluar y determinar la factibilidad y viabilidad económica y ambiental de la producción y comercialización de pargo rayado (Lutjanus synagris) en el Caribe colombiano, se efectuaron análisis financieros de la relación costo-beneficio, Utilidad Neta, Valor Periódico Uniforme Equivalente (VPUE) y Tasa Interna de Retorno (TIR), incorporando variables asociadas al cultivo en jaulas flotantes o estanques en tierra, dietas y mecanismos de comercialización. De acuerdo con los criterios de evaluación financiera, el proyecto generaría una riqueza adicional de 39,5%. La relación costo- beneficio demostró que se recuperaría el capital utilizado, obteniendo un adicional del 65% por unidad monetaria invertida. El periodo de recuperación de la inversión sería de 7 años y la TIR sería superior a la tasa de descuento del proyecto, la cual es de 18,95%, indicando, al igual que los demás criterios de evaluación, que el presente proyecto es favorable cuando se manejan financiaciones y un aumento del 5% sobre el precio por unidad establecido para peces ahumados en presentación comercial de 250 g con un modelo de cultivo asociado a jaulas flotantes. La matriz de Leopold permitió identificar que los principales impactos ambientales asociados al proyecto están involucrados en la etapa de construcción de las instalaciones y tanques de tierra

Mitogenomics of southern hemisphere blue mussels (Bivalvia: Pteriomorphia): Insights into the evolutionary characteristics of the Mytilus edulis complex

Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere (M. trossulus, M. edulis, M. galloprovincialis, M. californianus and M. coruscus) and three in the Southern Hemisphere (M. galloprovincialis, M. chilensis and M. platensis). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another fr om the Pacific M. chilensis. These mitogenomes exhibited similar architecture to those of other genomes of Mytilus, including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic divergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species.Link_to_subscribed_fulltex

Variation in Thermal Sensitivity and Thermal Tolerances in an Invasive Species across a Climatic Gradient: Lessons from the Land Snail Cornu aspersum

The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Inter-and intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e.g., critical and lethal limits), influencing the biogeographic patterns of species' distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermal-coma recovery times, expression of heat-shock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the "hotter is better" and the generalist-specialist trade-offs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints ("hotter is better") and thermal adaptations to their local environments (generalist-specialist trade-offs). This finding is also consistent with some thermal tolerance indices such as the Heat-Shock Protein Response and the recovery time from chill-coma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heat-coma recovery. © 2013 Gaitán-Espitia et al.Link_to_subscribed_fulltex

Cool-edge populations of the kelp Ecklonia radiata under global ocean change scenarios:strong sensitivity to ocean warming but little effect of ocean acidification

Kelp forests are threatened by ocean warming, yet effects of co-occurring drivers such as CO2 are rarely considered when predicting their performance in the future. In Australia, the kelp Ecklonia radiata forms extensive forests across seawater temperatures of approximately 7-26°C. Cool-edge populations are typically considered more thermally tolerant than their warm-edge counterparts but this ignores the possibility of local adaptation. Moreover, it is unknown whether elevated CO2 can mitigate negative effects of warming. To identify whether elevated CO2 could improve thermal performance of a cool-edge population of E. radiata, we constructed thermal performance curves for growth and photosynthesis, under both current and elevated CO2 (approx. 400 and 1000 µatm). We then modelled annual performance under warming scenarios to highlight thermal susceptibility. Elevated CO2 had minimal effect on growth but increased photosynthesis around the thermal optimum. Thermal optima were approximately 16°C for growth and approximately 18°C for photosynthesis, and modelled performance indicated cool-edge populations may be vulnerable in the future. Our findings demonstrate that elevated CO2 is unlikely to offset negative effects of ocean warming on the kelp E. radiata and highlight the potential susceptibility of cool-edge populations to ocean warming.</p

The hibernating South American marsupial, Dromiciops gliroides, displays torpor-sensitive microRNA expression patterns

When faced with adverse environmental conditions, the marsupial Dromiciops gliroides uses either daily or seasonal torpor to support survival and is the only known hibernating mammal in South America. As the sole living representative of the ancient Order Microbiotheria, this species can provide crucial information about the evolutionary origins and biochemical mechanisms of hibernation. Hibernation is a complex energy-saving strategy that involves changes in gene expression that are elicited in part by microRNAs. To better elucidate the role of microRNAs in orchestrating hypometabolism, a modified stem-loop technique and quantitative PCR were used to characterize the relative expression levels of 85 microRNAs in liver and skeletal muscle of control and torpid D. gliroides. Thirty-nine microRNAs were differentially regulated during torpor; of these, 35 were downregulated in liver and 11 were differentially expressed in skeletal muscle. Bioinformatic analysis predicted that the downregulated liver microRNAs were associated with activation of MAPK, PI3K-Akt and mTOR pathways, suggesting their importance in facilitating marsupial torpor. In skeletal muscle, hibernation-responsive microRNAs were predicted to regulate focal adhesion, ErbB, and mTOR pathways, indicating a promotion of muscle maintenance mechanisms. These tissue-specific responses suggest that microRNAs regulate key molecular pathways that facilitate hibernation, thermoregulation, and prevention of muscle disuse atrophy.Link_to_subscribed_fulltex

Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO2 waters are not preadapted to ocean acidification

Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally over-calcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hyper-calcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 vs. 1200 µatm), the over-calcified morphotypes showed the same growth inhibition (−29.1±6.3 %) as moderately calcified morphotypes isolated from non-acidified water (−30.7±8.8 %). Under the high-CO2–low-pH condition, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC ∕ POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. The high-CO2–low-pH condition affected coccolith morphology equally or more strongly in over-calcified strains compared to moderately calcified strains. High-CO2–low-pH conditions appear not to directly select for exceptionally over-calcified morphotypes over other morphotypes, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turnover and large population sizes, do not necessarily exhibit adaptations to naturally high-CO2 upwellings, and this ubiquitous coccolithophore may be near the limit of its capacity to adapt to ongoing ocean acidification