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

First report of the dynamic populations (structure size, growth, size at first maturity, longevity, natural mortality, and recruitment pattern) of black brotula Cherublemma emmelas in the Gulf of California. Growth parameters (L, k and to) were estimated using the von Bertalanffy model. The ELEFAN II method was used to estimate recruitment pattern and Taylor’s equation to estimate longevity. Natural mortality was determined using Pauly’s equations and Jensen’s. Size at first maturity was obtained by adjusting a logistics model. During four cruises on board the BIP-XI research ship, 2148 specimens were caught at 119-499 m depth in February and May 2005, and June and October 2007. The size structure showed a bimodal distribution with lengths from eight to 32 cm of total length and 15.9 cm average size. The biometric relationship between weight and length showing allometric growth rate (b ≠ 3) for sex. The fitted growth parameters were L∞ = 33 cm; k = 0.6 yr-1; to = -0.26 year indicated a moderate growth, while longevity was five years of age. Size at first sexual maturity was 18.8 cm, and natural mortality was 0.77 yr-1 (by Pauly) and 0.90 (by Jensen). The recruitment pattern showed peaks in June and July.

Reefs are the most biologically diverse marine ecosystems; therefore, to conserve the vast array of marine species that depend on them is vital. Many coral reefs around the world are under threat of extinction due to factors related to climate change and anthropogenic action. Studies have shown that specific infections develop at normal ocean temperatures and that warmer temperatures make the disease even more virulent. Also, as temperature increases, the infection in already infected corals becomes lethal. Thermal stress and the presence of pathogenic bacteria from the contribution of organic matter generates pathological affections in coral tissue, such as the White Band, Black Band, Yellow Band, White Plague, and Bacterial Whitening. This stimulates, in the short term, loss of coral cover and in the long term, negative impacts on the faunal composition of marine ecosystems. This review aims to present scientific information generated in the identification of different pathogenic bacteria that affect the health of corals.

Lipids requirement of tropical gar Atractosteus tropicus prejuveniles and juveniles was evaluated on growth, survival, chemical composition and apparent digestibility coefficient (ADC). Four semi-purified experimental diets (5, 10, 15 and 20% of lipids) were obtained with a mix of menhaden oil and soybean lecithin (2:1 ratio). Two trials were carried out, first with 600 prejuveniles of 0.5 g (35 days post-hatching, dph) for 56 days, and the second with 160 juveniles of 15 g (two-months-old) for 42 days. In the first trial, 15 (40.8 g) and 20% (40.2 g) lipid diets showed the best weight. Significant differences were obtained in condition factor (CF), daily lipid intake (DLI), hepatosomatic index (HSI), crude protein, ashes, nitrogen-free extract, moisture and ether extract between treatments. In the second trial, fish fed with the 10% lipid diet obtained the highest weight (89.1 g) compared with the other treatments. Significant differences were recorded for weight gain (WG), feed conversion ratio (FCR), specific growth rate (SGR), condition factor (CF), and lipid efficiency rate (LER). Also, significant differences were obtained in crude protein, ether extract, NFE, gross energy, apparent lipid ADC, protein ADC and dry matter ADC. The polynomial models applied to both trials indicated an optimum lipid requirement of 17% for 0.5 g juveniles and of 9% for 15.2 g juveniles.

Ophiothela mirabilis is native to the Pacific Ocean and has recently invaded the Caribbean and the southwestern Atlantic. In this study, using SCUBA diving techniques, we observed specimens of the invasive O. mirabilis in association with an octocoral host (Leptogorgia punicea) at the equatorial margin in the southwestern Atlantic (03°32′S, 38°47′W). We filled a gap of more than ~1,500 km between the Amazon reefs and the coast of Pernambuco State. The results indicate that O. mirabilis has invaded ~6,700 km of coastline in the southwestern Atlantic in the last 17 years. Moreover, our results support the hypothesis that the consistent color pattern of specimens from Brazil, French Guiana, Saint Vincent, and Tobago indicates the existence of a single lineage proliferating by asexual reproduction. Because the South Atlantic is the most recent of the oceans, as well as a hotspot for tropical biodiversity, much more information on invertebrate bioinvasions in this region is needed.

The present work reviews the different biomarkers and organisms that have been used to assess pollution in aquatic ecosystems of Mexico in the last 16 years. Ninety-three publications were reviewed; they showed that 70 species, most of them native (70%), have been used for this purpose. Fish have been the most commonly used group, but other non-conventional organisms have also been used. Biomarkers of oxidative stress such as catalase and superoxide dismutase activity, as well as cellular lipid peroxidation, were the most widely used and versatile. Those used less frequently included Acetylcholinesterase, Ethoxyresorufin-Odeethylase or Metallothionein. The omic approach was used for Cytochrome P450, Vitellogenin and heat shock proteins. Sixty-two percent of the species were used only on one occasion during the period studied here, while 13% were used more than twice. Girardinichthys viviparrus and Goodea atripinnis were the most frequently used species due to their regional endemism, but their use was restricted to the center of the country. Forty-four percent of the studies evaluated the data from at least two weather stations, and only 10% of the studies monitored pollution levels during more than two seasonal cycles. In Mexico, traditional and omic biomarkers are commonly used by researchers; however, further investigation is needed to determine which species and biomarkers should be used for each region and particular situation. It requires a joint effort between research centers and public funding agencies for the development of regional and national monitoring networks.

The current study aimed to describe the massive mortality of farmed Nile tilapia Oreochromis niloticus associated with the monogenean Gyrodactylus cichlidarum from the northwestern Mexican Pacific coast. The ectoparasite was identified using measurements of the hard parts and compared with previous literature. Approximately 20,000 tilapias were subjected to subsequent losses over a three day period, a total of 2% of the initial seed stocked died due to the presence of this gyrodactylid parasite. The presence of the monogenean was the principal cause for chemical treatments. There is no doubt that infections by parasites have major consequences for species of small fish in culture and must consequently be considered as a fundamental factor within any system of aquaculture. A histo-pathological examination of the gills of fish showed the presence of the monogenean attached to the fi laments was causing hyperplasia. The fish showed no signs of bacteria or virus infection. This study reports for the first time the occurrence of massive mortality caused by this monogenean in a tilapia fish farm in the Mexican Pacific and also extends their known geographical distribution.  

Fish actively select an adequate environment that fits their optimum culture/preferred temperature, this mechanism is called thermoregulatory behavior. However, what exactly is this mechanism, how does it work and what can we learn from it? Helped by their thermal limits, fish avoid temperature variations not favorable for their maximum growth. They find a thermal window where optimal temperature culture is located and use it in the best way possible for all activities. The present study is based on thermal biology studies, and its purpose is to learn the aerobic scope functions on Pargo-UNAM juveniles. The importance of this study is related to the fact that Pargo-UNAM fish, being a hybrid, has five different genetic backgrounds. We found that acclimation temperature influenced the preferred temperature of Pargo-UNAM, having a metabolic adjustment in the 20-32ºC range; the Final preferendum obtained was 29.5ºC. The maximum and minimum range of critical thermal limits was between 39.2-43.5ºC and 8-14.9ºC, respectively. The thermal window had an area of 355.2ºC2 . The acclimation response ratio had a 0.40-0.35 interval for CTMax, and 0.52-0.69 for CTmin. Chase method used in Pargo-UNAM caused a maximum aerobic scope at 29ºC. Blood lactate concentration was the highest in fish acclimated at 20ºC; these values decreased while acclimation temperature increased. Results from Pargo-UNAM juveniles showed that these can be grown successfully in a 26-32ºC temperature range, with their greater performance at 29ºC, where the aerobic scope was at its maximum capacity

Laguna Verde Bay, a World Biosphere Reserve, seems to be barely uncontaminated due to its isolated geographical position (18 km south of Valparaíso, Chile) and low amount of anthropogenic activities. At its coastal border, there is a thermoelectric generator (using coal since 1939 and diesel since 2007 as fuel), a small village (≈10.000 inhabitants) and a local fishermen’s wharf. A freshwater creek flows into the beach, creating a small coastal pond that sporadically overflows into the bay. With the objective of estimating the origin of the Laguna Verde Bay surface sediments and its heavy metal pollution level, the content of Total Organic Matter (TOM), organic carbon to total nitrogen ratio (C:N ratio), stable carbon isotope ratio (δ13C), Al, Fe, Cu, Mn, Pb and Hg in samples collected in August 2015, were measured. According to the δ13C values, the sediment origin was mostly terrestrial, with an allochthonous content greater than 50%. Since there is no legislation in Chile to establish the heavy metal concentrations for unpolluted marine sediments, a normalized metal enrichment factor (NEF) was computed to infer the contamination level. Despite the high Fe and Pb contents in the bay’s sediment at two stations (13.3 mg g-1 and 18.0 µg g-1, respectively), the NEF values in the bay generally correspond to a low level of pollution.

The aim of this study was to evaluate the growth performance and survival of the Pacific white shrimp (Litopenaeus vannamei) with red tilapia hybrid (Red Florida: Red Yumbo) and spotted rose snapper (Lutjanus guttatus), stocked at different densities in intensive brackish water mix-culture systems compared with monoculture of shrimp. The experiment, conducted in twenty-one plastic tanks (750 L) was set up to evaluate water quality, growth; production and survival of shrimp, tilapia, and snapper, for 60 days. Three replicates were assigned to seven treatments: After 30 day, initial densities were unfolded (shrimp = 50 org m-3, tilapia = 16 org m-3 and red snapper = 8 org m-3).  Feeding rate was adjusted at 5 and 10% of body weight d-1 for shrimp and fish, respectively. The shrimp-tilapia mix cultures produced the higher nitrogen and phosphorus in water concentrations. Significant lower survival values were obtained for shrimp (60.0 ± 0.6%) cultured with snapper and for tilapia (79.0 ± 3.1%) reared with shrimp. Mean final biomass for shrimp, tilapia and snapper were higher for the mix-cultures (2.04, 7.7 and 2.9 fold increase, respectively) with respect to their initial biomass. The mix culture system allowed an increase in total production with lower feed conversion ratios, thus contributing with the system sustainability.

Circulating levels of estradiol, vitellogenin and prostaglandins could be references of oocytes quality in the aquaculture industry. This study evaluated the performance of 17β-estradiol (E2) and vitellogenin (Vtg) levels in plasma and prostaglandins in oocytes (PGE 2) during the reproductive period of Oreochromis niloticus in a commercial farm in Ecuador. Adults fish females were treated with estradiol-synthetic (ES) and tilapia pituitary extracts (TP) during 25 days. For quantification of E2 and PGE 2, an enzyme-linked immunosorbent assay (ELISA) was used, while for Vtg relative quantification a Western blot analysis was performed. Circulating E2 concentrations were different during the first week of follow-up (P < 0.05) resulting in different levels of Vtg per treatment (P < 0.05) affecting on gonadal growth. The ovaries had an asynchronous development, where the mature oocytes proportions were higher with ES and TP than control. Relative fecundity was different between treatments (P < 0.05), where TP generated 15.7 ± 5.8 oocytes per g of spawning female. Furthermore, concentrations of PGE 2 were different between treatments (P < 0.05). The information reported in this study will be useful to improve the reproduction methods and have some biological signals before ovulation in tilapia commercial culture.