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

Background Electromagnetic pulses that precede earthquakes, and the ensuing crust deformations and vibrations, have been associated with unusual animal behavior (UAB), most commonly in terrestrial species but also in certain marine species, chiefly in the Chordata phylum (eg fish, cetaceans). Goals . The present study explored the occurrence of earthquake-related UAB in an entirely new marine phylum, the Echinodermata. Methods.   Formal and informal surveys conducted by fishing vessels and pre- and post-earthquake along the southern coast of Belize (Central America) were collated. Results The first cases of post-earthquake UAB in echinoderms were documented. They involved thousands of individuals of the holothuroidsIsostichopus badionotus and Holothuria mexicana spawning on May 29 2009 and January 10 2018, respectively. These rare accounts represent the first direct correlation between an earthquake and spawning activity, which occurred outside the normal spawning season and at an unusual time of day. Conclusion. While a growing number of reports indicate that many terrestrial and a smaller number of marine species can change their behavior before and during an earthquake, post-earthquake effects related to reproduction have apparently never been reported before in the animal kingdom. While underlying mechanisms remain unclear, holothuroid echinoderms may be reacted directly or indirectly to seismic activity, or the pressure change generated by it.

Background. Until 2015, the aquatic mammal’s biodiversity in the Mexican Caribbean was unknown, but was in that year when 18 species were confirmed to be distribute in this region, none of them a Rorcual species. Goals. The aim of this work is to report the first sighting of a Balaenopteridae whale in the Mexican Caribbean. Methods. CONANP patrolling activities at the National Park Isla Contoy were conduced. Results On 2th August 2018, a stranded-live whale was found. The animal was identified as a ~18m (in length)  fin whale Balaenoptera physalus (Linnaeus, 1758). Conclusions. This note is the first confirmed record of this species in the Mexican Caribbean increasing the list of confirmed aquatic mammal species distributed in this region.

Background. Probiotics in aquaculture are becoming important to improve the growth of fish, because of some useful modifications of physiological process, and consequently in fish growth.Goals.To assess the effects of two autochthonous bacterial strains, with probiotics features, on rainbow trout growth and digestive enzyme activities. Methods. In this study, was tested the effect of Bacillus pumilus (BP), Bacillus sp. (BSP) and the mixture (BPSP), on the growth and the activity of digestive enzymes of rainbow trout. The autochthonous strains, previously characterized as potentials probiotics in vitro, were administered individually at 1 x 107CFU g-1food, and as a mixture, the cellular concentration 0.5 x 107CFU g-1 food each one; during eight weeks. Results. Neither of the strains used generated significative growth, compared to the control. Were the fish fed with BSP that had the best growth, respect to BP and BPSP. The highest activity of enzymes was obtained in the fish treated with bacteria, and only in the case of BPSP the fish had a significant increase (P < 0.05) of proteases and amylase activity, compared with CTRL. Under the current trial conditions, strains BP and BSP, had no positive effects on growth and enzyme activities. The mixture improved the activity of protease and amylase of rainbow trout.

Background. One of the most relevant topics in ecology and evolution is understanding the relationship between biological  and functional diversity at the ecosystem level;  both important in the evolutionary processes and the structuring of complex communities.  Goals. In this essay, the explanatory hypotheses focused on global patterns of the distribution of species are described along with selected hypotheses relating species richness/biodiversity to ecosystem function, and the differentiation of the terms guild and functional group are discussed. Methods. Both biodiversity and functional diversity are key in the evolutionary processes and the structuring of complex communities and thus examples of functional equivalence of convergent evolution derivatives are presented in terms of the form and ecological habits of fishes of the Tropical Eastern Pacific Ocean. Finally, the importance of redundancy in ecosystem functioning is examined as well as the impact of environmental disturbances on ecosystem function. Results. In general, systems with low species richness and redundancy within functional groups are more vulnerable to disturbances. However, despite the extensive effort to understand the relationship between species richness/biodiversity and ecosystem functioning, there is no consensus on the effect of species loss on the functioning of the ecosystem. Some hypothesize that each species is unique and plays a unique role in the ecosystem whereas alternate hypotheses indicate that species overlap in function supporting sustainability at the ecosystem level, such that the removal of one species function may be replaced by another. Conclusions.The most widely accepted concept is that a greater number of species increases the efficiency in the use of resources and also provides resilience against environmental changes or impacts through functional redundancy.

Background: The diclofenac (DCF) is a non-steroidal anti-inflammatory drug (NSAID) that has been found in groundwater and superficial water, as a result of its high consumption in animal and human health. Moreover, DCF toxicity has been studied in different fresh-water animal models and it has been shown to have harmful effects on cladocerans, fish and amphibians, but the available information is still scarce in terms of induced alterations in organisms that are the basis of trophic levels such as rotifers. Goals: The present work assessed the effect of DCF on acute and chronic responses of the freshwater rotifer Lecane papuana (Murray, 1913). Methods: Acute toxicity tests were carried out to determine the LC50 of DCF (128.82 mg/L). Then, five sublethal concentrations were selected (1/160, 1/80, 1/40 y 1/20, y 1/10 of the corresponding LC50), and a control group (reconstituted hard water), to which amictic eggs were exposed to determine the effect on hatching and neonates were exposed to evaluate the effects on further fecundity and population increase in terms of r. Results: DCF diminished the r rate through the inhibition of eggs hatching and reduced fecundity of exposed females (fewer eggs per female) at 0.80 mg/L and higher concentrations. The effective median concentrations were about 700-fold lower than the corresponding LC50. Conclusions: These results indicate that DCF can affect rotifer populations at concentrations, that despite being higher than environmental concentrations, and due to the continuous release of DCF to the aquatic systems, would eventually have a negative impact on the exposed populations.  

Background. The Antillean or sharpnose shark is one of the main exemplars of shark species in the commercial catch in southern Gulf of Mexico. Oceanic dynamics on the planet Earth varies year-on-year due to the oscillation of solar radiation; fish abundances (and catches) likely respond to these oscillations. Goals. This study focuses on the analysis of landings variability of the antillean sharpnose shark (Rhizoprionodon terraenovae) in the Mexican coast of the Gulf of Mexico, from 1940 to 2006, and its possible connection with solar activity as assessed by the average sunspot number (Zürich Index). Methods. A polynomial curve by least-squares best fitting was used to eliminate the tendency from the sharpnose shark landings time series. Spectral techniques of Maximum Entropy (ME) and Fast Fourier Transform (FFT) were used to analyze the time series of sharpnose shark landings and the Zürich Index. Results. The time series of sharpnose shark landings showed a remarkable spectral peak with a period of about 12.8 years, while the Zürich Index showed a marked peak at a period of 11.6 years. Cross-correlation revealed a delay between the average number of solar spots and sharpnose shark landings. Conclusions. This work is the first to report such a low frequency variability for landings of the Rh. terraenovae fishery in the Gulf of Mexico, using a particular methodology that can provide information for the design of predictive models in the future. The analyzed landing volumes of the sharpnose shark Rh. terraenovae showed as a result a periodical behavior in coincidence with Wolf’s solar activity cycle of 10.6 years.

Background: The exploitation of aquaculture resources, such as the freshwather crayfish C. montezumae (Mexican endemic crustacean), is related with fertility of females due to the available number of postlarvae that can be cultivated. Goals: To evaluate the impact on reproductive aspects of the sex ratio C. montezumae in relation to obtained postlarvae. Methods: The impact of three sex ratio of males and females in the number of ovigerous females, fertility, fecundity, hatching time and the relation between these variables was determinate under laboratory conditions. Results: The analysis of variance shows that sex ratio 1:1 produced the highest number of ovigerous females (61) and a higher number of postlarvae (2451). When comparing the average fecundity (37 eggs per female) and the mean hatching percentage (97.96%), no significant differences between treatments were obtained. Females of first reproduction influenced the absence of linear relationships between size (weight and length) and reproductive aspects evaluated (fecundity and fertility). Conclusions: The sex ratio 1:1 is set as the optimum to get the highest number of postlarvae. The absence of linear relationship between size and studied variables provides the opportunity to study the influence of second breeding females to determine the technical conditions of higher postlarvae production in this specie.  

Background: Chimaeras are cartilaginous fish that live in waters more than 200 m deep. There are two species of the genus Harriotta in the Rhinochimaaeridae Family, but only one, H. raleighana Goode & Bean 1895, occurs in Mexican waters. In almost one hundred years it has been collected only six times in the Mexican Pacific, and it is considered a rare and poorly known species. Goals: this note describes the last and most recent specimen collected in this region. Methods: in early 2018 a specimen was found in a fishing net in the south of Bahia de Banderas, Jalisco, and represents the second record in the area, the only place in Mexico with two records. Results: data and measurements are included. A female weighing 1.343 kg, with a total length of 85.5 cm, corresponding to the largest specimen ever collected in México. Digestive tract was empty. Conclusions: this is the second report for this species for Jalisco, particularly in Bahía de Banderas, the only place in Mexico with two records of this rare species.