Observations on the early development of the kelpfish Myxodes viridis (Clinidae) with the first description of their spawning habitat in subtidal kelp forests (Lessonia trabeculata)

The spawning sites, embryonic development, and initial larval stages were described for the Chilean kelpfish, Myxodes viridis. Six different egg clutches were found attached by an elastic filament to the fronds of the subtidal kelp, Lessonia trabeculata, at shallow depths (0-7 m). All egg clutches were cared by one large (>15 cm TL) male, and egg color varied depending on the developmental stage. Embryonic development until hatching was categorized into 7 stages, which were completed within about 18 days in the laboratory. Recently hatched larvae presented fully pigmented eyes, a well-developed mouth with major shape changes in the head during the first week suggesting their ability to feed on plankton early in their larval development.

The intensity of kelp harvesting shapes the population structure of the foundation species Lessonia trabeculata along the Chilean coastline

Kelp are foundation species that support high levels of biodiversity and, either directly or indirectly provide a wide range of ecological goods and services to human society. In recent decades, due to the high demand for kelp-derived products such as alginate, commercial wild harvesting has increased, leading to declines of kelp biomass in some regions. Chile accounts for 40% of the global kelp harvest, with the subtidal kelp, Lessonia trabeculata being one of the main target species. Currently, however, there is a lack of information on how different degrees of harvesting intensity, governed by distinct management regimes and their enforcement influences L. trabeculata populations. Here we examined the effect different management regimes, characterised by distinct levels of exploitation of kelp and kelp-associated fauna, have on L. trabeculata density and morphology along ~ 1600 km of the Chilean coastline. The findings demonstrated that harvesting intensity likely influences both L. trabeculata density and morphology. Juvenile density of L. trabeculata was five times higher in the most harvesting-affected areas, while kelp morphology values, including holdfast diameter, number of stipes and total length, were always higher in the less-intensively harvested areas. Our study suggests that different degrees of protection can influence density and morphology of subtidal L. trabeculata populations, which in turn has important implications for the conservation of the kelp forest ecosystems and management of this important fishery.

The seaweed resources of Peru

The coast of Peru (3.5–18°S) is one of the most productive marine areas in the world. The updated seaweed checklist reports a total of 260 specific/intraspecific taxa, of which the Rhodophyta show the highest number (185 species), followed by Chlorophyta (41 species) and Phaeophyceae (34 species). Since 2012, an increase in molecular studies has been reported mostly in Rhodophyta, while Chlorophyta and Phaeophyceae have lagged far behind. Utilization of seaweed resources has been based on artisanal collection from natural beds. These are mainly consumed fresh or salt-dried (Chondracanthus chamissoi and Porphyra/Pyropia species), or exported for polysaccharide extraction (Lessonia nigrescens, Lessonia trabeculata, Macrocystis pyrifera). Although some regulations for brown seaweed extraction exist, overexploitation is a constant threat that must be addressed. Biomass from seaweed farms accounts, at most, for only 4% of the total annual landings, and there is a decreasing trend on seaweed aquaculture production since 2012. However, some cultivation projects for C. chamissoi and Porphyra/Pyropia species are currently being undertaken. In addition, recent studies have started to explore new uses of commercial and non-commercial seaweeds. Uncovering the Peruvian seaweed diversity and establishing well sustained culture and management projects are essential for utilizing and preserving the seaweed resources of Peru.

Incremento de la viabilidad, producción de especies reactivas de oxígeno, IL-1 y TNF-α en células mononucleares de sangre periférica humana tratadas con fucoidan de Lessonia trabeculata

Las algas pardas constituyen una fuente de alto contenido de polisacáridos como los fucoidanos que poseen importantes propiedades inmunomoduladoras. El objetivo fue determinar la viabilidad de células mononucleares de sangre periférica humana (CMSPh), producción de óxido nítrico (NO), especies reactivas de oxígeno (ROS) y de las citoquinas proinflamatorias IL-1α, IL-6, TNF-α e IFN-γ en cultivos tratados con fucoidan de Lessonia trabeculata. Se empleó fucoidan de Lessonia trabeculata proveniente de la bahía San Nicolás de Marcona-Ica. Las CMSPh se aislaron empleando Ficoll-Hypaque, se distribuyeron a una concentración de 1x105 células/pocillo en medio RPMI-1640 completo y se trataron con diferentes concentraciones de fucoidan durante 24 y 48 h. La actividad citotóxica se determinó por la reducción de MTT, la producción de NO por la reacción de Griess y las ROS por la reducción del NBT. La producción de citoquinas se cuantificó por ELISA. El fucoidan de L. trabeculata estimuló la proliferación de CMSPh y produjo el incremento de ROS a concentraciones de 100-2000 μg/mL respecto al control (p<0.001), la reacción para nitritos resultó negativa. El fucoidan incrementó la producción de IL-1α y TNF-α a concentraciones de 100 y 10 μg/mL respectivamente, mientras que la producción de IL-6 e IFN-γ no mostró diferencias significativas. Se concluye que el fucoidan de L. trabeculata estimula la proliferación de CMSPh, producción de especies reactivas de oxígeno y las citoquinas proinflamatorias IL-1α y TNF-α que poseen importantes propiedades inmunomoduladoras.