Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

French Guiana region is one of the most productive in the world and hosts a wide variety of marine vertebrates. In the same time, anthropogenic activities are a growing concern in French Guiana, both in coastal and offshore areas. However, few studies are published on marine mammals, seabirds and potential interactions. Twenty-three marine mammal species are known to occur in the Exclusive Economic Zone (EEZ) and important seabird breeding sites are located in the area. Most of the existing literature relates to breeding birds and coastal cetaceans, but the continental slope appears to be an essential habitat for marine mammals and seabirds. Between October 22 and November 23, 2017, an oceanographic survey was conducted on the Guiana slope to study the quality of sediments and water. Three marine fauna observers (MFOs) were onboard to record sightings of marine mammals and seabirds opportunistically. During 462 h of visual effort in good sighting conditions, 313 sightings (824 individuals) were recorded: 61 marine mammals (501 individuals) and 252 seabirds (323 individuals). Seven seabird families were observed: Laridae (42%), Fregatidae (26%), Procellariidae (12%), Stercorariidae (10%), Hydrobatidae (4%), Sulidae (2%) and Phaethontidae (1%). 3% concerned wader species. The most frequently observed seabird species was the magnificent frigatebird (Fregata magnificens), as well as the common tern (Sterna hirundo), Cory’s shearwater (Calonectris diomedea) and the pomarine jaeger (Stercorarius pomarinus). Many Delphinidae species were observed (Stenella longirostris, Stenella attenuata, Stenella frontalis, Delphinus delphis, Tursiops truncatus) in addition to sperm whales (Physeter macrocephalus) and humpback whales (Megaptera novaeangliae). Only a few sightings of humpback whales have been previously recorded in this area. Sighted individuals were mainly mother-calf pairs suggesting that the area may be an extended part of a calving ground for humpback whales.

The activity of fish acid proteases is strongly dependent on the pH, and many basic and applied works had focused on researching the pH-profile of digestive proteases using different buffered media. Nevertheless, enzymatic activity is also known to be affected by the ionic strength (IS) of the medium. The present work is aimed at researching the combined effects of pH (2.5, 3.0, 3.5, 3.75 and 4.0) and IS (50, 100 and 200 mM) on the protease activity of gastric extracts of juvenile Coho salmon Oncorhynchus kisutch. It is concluded that the activity of Coho salmon gastric proteases is maximal at pH 2.5-3.0, drops towards pH 4.0 irrespective of ionic strength, and they showed a lower activity at IS 50 mM in comparison to IS 100 or 200 mM. The present results point out to the convenience of considering the effect of ionic strength when measuring the activity of fish gastric proteases.

Microanalysis of elemental composition using dispersive energy X-ray is a biomonitoring tool to identify hazard metals. Using scanning electron microscopy/energy dispersive X-ray spectrometry, we studied the bioaccumulation of toxic metals in the lorica of diatoms, dinoflagellates, rotifers, cladocerans, copepods and fish scales in the aquatic ecosystems of northeastern Quintana Roo, Mexico. The study was carried out in the coastal zone, where samples were collected in 16 exposed bodies of water, including dolines, mangroves and lagoons. Microanalysis of the most abundant organisms revealed evidence of the presence of essential trace elements and metals (Ag, Al, Br, Cd, Cu, Fe, Hg, Pb and Zn) in the lorica and scales. Furthermore, interpolation maps of the northeastern zone of Quintana Roo were produced to pinpoint critical pollution zones of Cd, Hg and Pb, elements that are deemed toxic to the health of humans and aquatic ecosystems. In conclusion, elemental microanalysis of species native to the Mexican state of Quintana Roo using X-ray is a powerful tool for aquatic and toxicological biomonitoring of hazardous metals.

The lionfish is the first invasive species that came to the western Atlantic region to establish itself as an ecological and economic threat to coral ecosystems and commercially important consumption species. Fifteen specimens were collected in Quintana Roo, Mexico, to analyze the chemical composition of the lionfish (Pterois volitans) as a strategy to promote its consumption by the population. They were gutted, filleted, homogenized and chemically analyzed. The analyzed LF had an energetic protein content of 103.89 kcal 100 g-1 of the fillet (20.19%) and a fat percentage of 2.56%. The content of P, Ca, Na, K and Mg were 174.15, 26.09, 81.47, 339.73 and 30.27 mg 100 g-1, respectively. The most abundant essential amino acid was lysine (12.98 g 100 g-1 protein). The present work is important because it reports that the LF could be used as food with the right quantity and quality of protein, and its consumption would diminish its environmental impact.

The Puelo and Petrohué rivers were surveyed between April 2016 and February 2017 to assess the presence and seasonal abundance of Didymosphenia geminata in the wild aquatic systems of these two important rivers in southern Chile. Didymo was reported in the Puelo River in 2012, while it was declared absent from the Petrohué River before this study commenced in the fall of 2016. Results showed that cells of D. geminata were recorded in both rivers, in the Phytobenthos as well as in the water column. However, the classical mucilage which characterizes this plague was only recorded in one of the sampled rivers (Puelo). The mucilage was not recorded in any of the sections sampled in the Petrohué River, which was attributed to the high concentration of phosphorous present in the system. The concentration of phosphorous recorded throughout the study in the Puelo River was low. However, differences in the recorded presence or absence of D. geminata between sampling sites on the Petrohué River was mainly attributable to the availability of incident sunlight. This study records for the first time the presence of D. geminata in the Petrohué River.

The homeopathy has been practiced for many years, mainly using rodent as a research model. Zebrafish have been used as an animal model in different scientific areas and may represent an important model in studies with this therapy. This paper aimed to evaluate the action of Homeopatila 100® on the growth, the action on the liver and reproduction of zebrafish. The study was carried out with 192 six months old animals. The experimental period was three months, being evaluated the growth, the hepatosomatic and viscerosomatic indexes, the number of hepatocytes per area and the percentage of glycogen in these cells, performing the hepatic histology of males and females. It was evaluated the reproduction of the animals, checking the production and probability of hatching of the eggs. It was found that homeopathy increases the number of hepatocytes and glycogen in females, as well as improved the reproductive indices evaluated.

A new size record of the lollipop shark Cephalurus cephalus is described. It is a 367 mm of total length female captured offshore Bahía Magdalena, Mexico. This is a contribution to the knowledge of rare deep-sea Chondrichthyans of demersal habits.

The present study evaluated the growth performance and whole-body composition of the hybrid red tilapia (Oreochromis mossambicus × O. aureus) raised in saltwater and fed three experimental diets containing different protein levels (25.6, 30.8 and 35.6% CP; crude protein). The hybrid red tilapia showed a high production performance across all dietary treatments: specific growth rate (SGR) = 3.12-3.51% body weight d-1; weight gain = 391-503%; feed conversion ratio (FCR) = 0.90-1.07; thermal growth coefficient (TGC) = 1.50-1.67; condition factor (CF) = 0.19-0.26. Dietary protein content significantly affected feed intake; fish fed the 30.8% CP diets displayed higher feed intake than those fed the 25.6% CP diet. Although the protein efficiency ratio (PER) was not significantly affected by dietary treatments, fish fed 25.6% CP diet demonstrated numerically higher values than those fed the other dietary treatments (4.34 vs. 3.06-3.35). The viscerosomatic index was significantly reduced in the 25.6% CP group compared to 30.8 and 35.6% CP groups. Regarding the whole-body composition, dietary protein affected all parameters, except lipid content. Fish fed the 30.8% CP diet exhibited significantly reduced relative protein content and elevated ash content in the whole-body in comparison to other dietary groups. The results of the present study indicated that juveniles of hybrid red tilapia accepted all dietary treatments. However, according to polynomial regression analyses based on PER and the high ash content in tilapias fed the 30.8% CP, it is suggested that the optimum dietary protein content for juvenile hybrid red tilapia was 25.6%.

This study assessed the effect of protein level in diet and feeding schedule on the digestive enzymatic activity of Macrobrachium tenellum juveniles. Freshwater prawn juveniles (0.31 ± 0.004 g and 32.48 ± 0.27 mm) were fed diets with 20, 25, 30, 35 and 40% crude protein (CP) (p/p). In a second experiment, feeding schedules were assessed at 08:00, 14:00 and 20:00 h with feed at 30% CP with juveniles of 0.22 ± 0.002 g and 29.36 ± 0.28 mm. In both experiments, five organisms were sampled after 60 days of treatment in a time-lapse of one hour (08:00 to 09:00 h) per experimental tank and treatment. The enzymatic extract was obtained from the complete organisms to determine specific general protease, trypsin, chymotrypsin, amylase and lipase activities. Greater general protease, trypsin and lipase activities were observed in feed at 40% CP. The feeding schedules with greater general protease, trypsin, lipase and amylase activities were found at 14:00 and 20:00 h. Chymotrypsin did not show differences among treatments at CP levels or feeding schedules. Protein level in diets for M. tenellum modified basal digestive enzymatic activity and increased proteolytic and lipolytic activities, while it decreased amylolytic activity as the inclusion of CP level increased in the diet; likewise, the activity was modified by feeding schedule, showing a direct correlation between the increase in digestive enzymatic activity and food offering at the end of the day.

The red seaweed Pyropia orbicularis is an economic important species that occurs predominantly in the high intertidal zone along the chilean coast where it experiences extreme conditions under daily turning tides. Its gametophytic phase has been demonstrated to have a high desiccation tolerance, both at the genomic and proteomic levels, but studies at the metabolomic level are still lacking. This research aimed at characterizing compounds related to desiccation stress tolerance by performing several phase solid extractions with different solvents. Bioactivity-guided fractionation (antioxidant and antibacterial activities) was made for a more specific characterization. Compounds identification was done using LC-MS/MS. Results showed that P. orbicularis produces different compounds depending on the state of hydration during the tidal cycle. For example, minoxidil was only found under hydration, while vincamine only during desiccation. It was also found that the main antioxidant activity was most likely due to lutein and the antibacterial activity could be mainly attributed to compounds of lipid nature such as phosphatidylethanolamine (PE), phosphatidylserine (PS) and monogalactosyldiacylglycerol (MGDG). These results help to get a better understanding of the stress tolerance mechanisms in P. orbicularis and place it like a potential source of bioactive compounds.