Scielo RSS <![CDATA[Latin american journal of aquatic research]]> vol. 48 num. 2 lang. en <![CDATA[SciELO Logo]]> <![CDATA[North Atlantic white shrimp <em>Litopenaeus setiferus</em> (Decapoda: Penaeidae) as an aquaculture target species for farming: a review]]> ABSTRACT Litopenaeus setiferus has been described as an economically important native species ranging from the north Atlantic along the coast of the Gulf of Mexico to Florida. Its reproduction has been studied in captivity, as well as some aspects of its nutritional physiology, diseases and adaptation to various environments, including nurseries. In terms of growth, L. setiferus has been compared with L. vannamei for its performance in ponds. As a native species, L. setiferus benefits local fisheries and is also used as a bait shrimp for recreational activity. The present review covers background information and recent advances in research and development efforts to determine its potential both for aquaculture in ponds and intensive biofloc systems (BFT), as well as for the stocking of fishing grounds. The collective research advances for this species presented in this review could help to sustain various strategies, including highly intensive techniques, to rehabilitate L. setiferus in connection with potential institutes. <![CDATA[Chilean Antarctic krill fishery (2011-2016)]]> ABSTRACT: Antarctic krill (Euphausia superba) is a key resource in the Antarctic region, as it is the primary food source for fish, whales, seals, flying birds, penguins and cephalopods. The high concentrations of the species and its possible uses -food for human and animal consumption and in the production of industrial, pharmaceutical and dietetic products- generates interest in the fishing industry. Its relevance motivated the implementation of administrative measures and international regulations for this fishery, which are summarized in this review. Chile is the only South American fishing country that has shown interest in participating in Antarctic krill fishery. Thus, between 1983 and 1994, the Fisheries Development Institute and some companies carried out fishing activities mainly aimed at prospecting and researching this species. However, starting in 2011, the factory trawler FV Betanzos began sustained commercial krill fishing aimed at krill meal production. This document analyzes the information collected by said vessel between 2011 and 2016, including areas of operation, fishing depth catches and CPUE obtained. Also, the main challenges faced by this fishery and the actions planned as solutions are assessed. <![CDATA[Diatomaceous earth application to improve shrimp aquaculture: growth performance and proximate composition of <em>Penaeus vannamei</em> juveniles reared in biofloc at two salinities]]> ABSTRACT Silicon dioxide has been used in aquaculture to increase the abundance of diatoms; however, its relationship with water quality or productive performance has not been investigated. Our study evaluated the effect of diatomite on water quality, growth performance and proximate composition of Penaeus vannamei reared in seawater (E1) and brackish water (E2) with biofloc. Two independent experiments (E1 and E2), each one with three treatments with biofloc were evaluated: treatments D with a weekly addition of diatomite (10 g m-3); the treatments D plus a continuous inoculum of diatom Chaetoceros muelleri (DD); and only biofloc like control, for E1 was used post-larvae with an initial body weight (IBW) of 0.0075 g; while in E2 was used juvenile with an IBW of 1.42 g. After seven weeks in E1, non-significant differences were registered in survival, weight gain (WG), specific growth rate (SGR) and feeding conversion rate (FCR) between DD treatment and control. However, in E2, the treatment D showed significantly higher WG (9.83 g) and SGR (4.25% d-1) compared to control (7.64 g and 3.86% d-1, respectively). Conversely, the FCR was lower in treatment D (1.16) compared to control (1.49). Non-significant differences were recorded in the proximate composition for shrimp, periphyton, and biofloc, among treatments in both experiments. Levels of nitrogenous wastes were similar among treatments. While in E2, the concentration of settleable solids was significantly higher in treatments with diatomite compared to control. Our results recommend the use of diatomite to improve the growth performance of shrimps cultured in brackish water with biofloc. <![CDATA[Histopathology and molecular identification of <em>Henneguya pseudoplatystoma</em>]]> ABSTRACT The present study proposes to characterize the parasites isolated during the initial phase of production in fish farms located in Mato Grosso do Sul in the central-western region of Brazil, using histopathology analysis and molecular techniques. A total of 340 hybrid surubim fish (Pseudoplatystoma reticulatum × P. corruscans) from four farms were examined during the co-feeding phase. Histopathology analysis showed that 10.9% (n = 37) of the fish were infected with parasites. Branchitis, lifting epithelium, hypertrophy of epithelial cells, lamellar fusion, aneurisms and infection in the bone tissue of the gill filament was observed. The parasite species was determined by amplification of the 18S rRNA gene followed by sequencing. The phylogenetic analysis of nucleotide sequences indicates a close relationship (99.6%) with Henneguya pseudoplatystoma reported to be infecting the hybrid Pseudoplatystoma. This study demonstrates the occurrence of H. pseudoplatystoma in hybrid surubim (P. reticulatum × P. corruscans) during the co-feeding phase in fish farms in Mato Grosso do Sul. Also, molecular techniques provide a faster and sensitive method to identify fish parasites, and may assist in the development of new management techniques aimed at improving the sanitary conditions contributing to the reduction of mortality rates in these animals. <![CDATA[An empirical relationship between sea surface temperature and massive stranding of the loggerhead turtle (<em>Caretta caretta</em>) in the Gulf of Ulloa, Mexico]]> ABSTRACT Two mass stranding events of loggerhead sea turtles (Caretta caretta) in the vicinity of the Gulf of Ulloa, Baja California Sur, Mexico, were analyzed during 2003-2006 and 2012-2014. Stranding events were related to the accumulation of consecutive days with lower sea surface temperature (SST) series for the corresponding periods using Pearson correlations. Our results showed that in both periods, a significant cross-correlation was observed between mass stranding and accumulation of consecutive days with temperatures below 18, 17, and 16°C, with a time lag of three to five months. Numerical evidence supports the hypothesis that although the loggerhead turtle mortality is caused by multiple factors under extreme cold events, the environment turns markedly unfavorable for these organisms. Side-effects on health and swimming behavior of the species C. caretta, compromise their ability to avoid obstacles or flee from predators, thus increasing their vulnerability to sickness or lethargy, and possibly leading to the massive stranding of weakened individuals or dead bodies to the beaches of the Gulf of Ulloa. Hence, while SST may not be the direct cause of turtle mortality, it can be a determining factor for the survival of this species. <![CDATA[Biological responses in gills and hepatopancreas of <em>Ucides cordatus</em> (Crustacea, Decapoda, Ocypodidae) as indicative of environmental contamination in mangrove areas in Maranhão State, Brazil]]> ABSTRACT This study aimed to identify alterations in gills and hepatopancreas of the crab Ucides cordatus as indicative of environmental contamination in mangrove areas subject to chemical effluents from port activities in Maranhão, Brazil. Samples of gills and hepatopancreas were removed from each animal and fixed in Davidson's solution until the procedure of histological technique. The biometric data (means and standard deviations) of the specimens collected in the study areas indicated that the crabs in the reference area are significantly (P &lt; 0.05) higher and heavier than the crabs collected in the potentially impacted area (port area). Gill alterations (rupture of pilaster cells, dilation of the marginal channel, cuticle rupture and necrosis) and hepatopancreas alterations (abnormal lumen, vacuolized B cells, pycnotic nuclei and necrosis) were significantly (P &lt; 0.05) more frequent in crabs collected in the port area than crabs collected in the reference area. These data indicate that the health of crabs is compromised due to the pollutants present in the mangroves that surround the port area in São Marcos' Bay. <![CDATA[The seasonal entrance of <em>Penaeus setiferus</em> and <em>Penaeus duorarum</em> postlarvae into Términos Lagoon, Campeche, México]]> ABSTRACT This study establishes the season for the immigration (recruitment) of Penaeus setiferus and P. duorarum postlarvae into Términos Lagoon, México, as well as the hydrological conditions that occur during this event. The abundance of postlarvae of both species was used to infer the reproductive period for each species. The zooplankton collection was carried out monthly for three years. The nets used were 50 cm in diameter, 1.5 m in length and 505 μm mesh size, and temperature and salinity were measured with an YSI. The fluvial discharges were taken from Comisión Nacional del Agua (CONAGUA). The harmonic pattern variation (HPV) was analyzed for each variable (density of postlarvae, salinity, temperature and fluvial discharge). A cycle was analyzed and divided into two episodes (rise and descent) to estimate the HPV of each postlarval species. The entrance of both postlarval species starts from June to September, with higher density in August, which decreases from October to May, with the lowest density in March. The first episode was established from June to August and the second episode in September. During the first episode the hydrological conditions were: high salinity (34), a warm temperature (30°C) and low accumulated fluvial discharge (2,828 m3 s-1), while, in the second, they were low salinity (28), a moderately warm temperature (29°C) and high accumulated fluvial discharge (3,934 m3 s-1). <![CDATA[Parental contribution in a cultivated stock for the spotted rose snapper <em>Lutjanus guttatus</em> (Steindachner, 1869) estimated by newly developed microsatellite markers]]> ABSTRACT The spotted rose snapper Lutjanus guttatus is a fishery relevant species from the eastern Pacific Ocean, with aquaculture potential. Species-specific genetic markers are needed for the genetic characterization of wild and cultivated populations to help management strategies. Eighteen hypervariable microsatellites were developed by Next Generation Sequencing and characterized in a wild population sample. Genetic diversity was high (observed heterozygosity = 0.88 ± 0.050; the number of alleles per locus = 13.4 ± 1.3) and few loci departed from the Hardy-Weinberg Equilibrium, leaving 14 loci potentially suitable for population genetic studies. A reduced panel of five loci was tested in a cultivated stock to determine the parentage of progeny (embryonated eggs; n = 413), to estimate the temporal contribution of each parental broodstock. The above resulted in the successful assignment of 95.6% of the progeny to its parental couple, representing 17 out of the 24 possible families. Two of the four females produced most of those progeny (97.3%). These females, which reproduced throughout the season, did not spawn on consecutive days. The contribution of males was evenly distributed during the season and occurred on successive days. Some microsatellites can be used in other lutjanids (L. peru, L. argentiventris, and Hoplopagrus guentherii). <![CDATA[Chilean benthic species identified as a new source of antibiotic substances]]> ABSTRACT Benthic marine organisms are a natural source of bioactive substances with applications in medicine to treat infections, cancer and other diseases. In Chile, this community possesses rich biodiversity that has been scarcely studied as a producer of bioactive substance so far. For that reason, we studied the potential production of antibiotic substances in 28 benthic species that inhabit the coast of the Tarapacá region in northern Chile, and belong to phylum Porifera, Cnidaria, Mollusca, Sipuncula, Annelida, Echinodermata and Chordata. The antibiotic activity was evaluated on ethanol extract obtained from their entire body or dissected tissues and was tested against Staphylococcus aureus ATCC 25923 with the diffusion agar method. According to the halo diameter, the antibiotic potency was classified as mild, regular or high. In this way, we could identify 21 benthic species as a producer of antibiotic substances with different antibiotic potency. This activity was found in more than one tissue and with regular or high antibiotic activity in the species; Acanthopleura echinata, Chiton cumingsii, Aulacomya atra, Fissurella crassa, Fissurella latimarginata, Luidia magellanica, Stichaster striatus, Arbacia spatuligera, and Loxechinus albus. The extracts obtained from the entire body and showed regular and high antibiotic activity were from the species; Phymanthea pluvia, Abarenicola affinis, Glycera americana, and Ophiactis kroyeri. In conclusion, northern Chile possesses a rich biodiversity of benthic species producer of antibiotic substances, and more research is encouraged to identify these substances with application in medicine. <![CDATA[How do spatial and environmental factors affect the fish community structure in seasonally flooded karst systems?]]> ABSTRACT Spatial and temporal variation of the physical and chemical conditions of coastal karst wetland ecosystems, which annually range from flooded to completely dry, generate a very dynamic fish community structure. We assessed the relative influence of spatial dependence and environmental factors on fish community structure in a seasonally flooded tropical karst system on the north-western coast of the Yucatan Peninsula, Mexico. Sampling was carried out between November 2009 and April 2010, while the area was inundated by seasonal floodwater. Fish biomass, abundance and species richness, as well as environmental variables and geographic location, were recorded. A variation partitioning analysis was performed to assess the influence of the spatial and environmental variables on the fish community using multiple regression, and a principal coordinates analysis of neighbor matrices (PCNM). Spatial factors had a greater influence on the changes in the community structure than the environmental factors. After spatial variation, environmental effects from conductivity, oxygen saturation, temperature and depth further shaped the community. These results imply that, despite the diversity of niches and wide variation in environmental conditions, the structuring force of the community is the spatial dynamic probably linked to species dispersal mechanisms and reproductive strategies. <![CDATA[Effect of the deficiency of nitrate and silicate on the growth and composition of the benthic diatom <em>Navicula incerta</em>]]> ABSTRACT Navicula incerta is a benthic diatom with potential use in nutrition and health for humans and aquaculture. Therefore, it is important to know its optimal growth conditions and biochemical composition. In this study, the effects of nitrate and silicate concentration on the growth kinetics and biochemical composition of N. incerta under laboratory conditions were measured. F/2 media was used as the control, and different concentrations of nitrogen (N/4, N/8 and N/16) and silicates (Si/4, Si/8 and Si/16) were evaluated. We measured cell concentration, chlorophyll-a and conducted proximal chemical analyses. It was found that different concentrations of nutrients affected the diatom's growth kinetics and affected the concentrations of ash, chlorophyll, protein, lipids and carbohydrates. The highest concentration of lipids was obtained in the limiting treatment of nitrogen N/8 (27.09%), while the lowest value was found with silicate Si/8 media (16.97%). Carbohydrates increased compared to the control, with the N/16 treatment presenting the maximal concentration (23.31%). Treatments with reduced nitrate (N/8 and N/16) demonstrated the lowest concentrations of protein (18.75 and 12.44%, respectively), while in reduced silicate treatments, no statistical differences (P ≥ 0.05) were observed. Therefore, media limited nitrogen and silicates affected the growth kinetics and proximal chemical composition of N. incerta. The growth of this species using the N/8 medium is a suitable method for increasing lipid concentration in N. incerta. <![CDATA[Evidence of illegal catch in the benthic artisanal fisheries of central Chile: patterns across species and management regimes]]> ABSTRACT Non-compliance with fishing regulations is a widespread phenomenon in fisheries worldwide, jeopardizing the recovery of stocks and ecosystem services. There is an urgent need to fill the gaps in our understanding of the scale and nature of illegal fishing in artisanal fisheries, balancing the advances made in industrial fisheries. We explored patterns of fisher compliance with the existing minimum legal size (MLS) regulation in the small-scale benthic fisheries of central Chile. We focus on two of the most conspicuous species (loco Concholepas concholepas and keyhole limpets Fissurella spp.) and comparing two management regimes: management areas (MAs; local name for territorial use rights for fisheries) and open access areas (OAAs; no spatial entry restrictions). We also evaluated the effect of the spatial distribution of MAs, which determines the availability of OAAs on compliance. For both species, we measured the size of individuals in the catch in two consecutive years. We developed an index that accounts for the availability of open access areas per fisher. We found that a) the number of undersized individuals in the catch in OAAs is enormous, b) management regime influences both the median size and fraction of the undersized catch, and c) as the availability of OAAs per fisher decreases, illegal fishing increases, demonstrating the need to manage the levels of effort displacement in designing area-based instruments for management and conservation. Our findings also highlight the need to a) analyze the benefits of area-based instruments at the seascape scale, and b) develop and adapt instruments to prevent illegal fishing. <![CDATA[Antarctic demersal finfish around the Elephant and the South Orkney islands: distribution, abundance and biological characteristics]]> ABSTRACT A research survey for demersal finfish was completed using bottom trawl fishing gear, following a random stratified sampling design, between 50 and 500 m on shelf areas of Subarea 48.1 (Elephant Island) and Subarea 48.2 (South Orkney Island). An acoustic survey was simultaneously carried out to enhance knowledge of bathymetry and the distribution of fish and krill in the studied area. The cruise took place between the 6 and 27 January 2018. A total of 36 hauls were carried out, 15 around Elephant Island and 21 around the South Orkney Islands. A total of 37 fish species were caught with a total biomass of 19,112 kg. The main species encountered included Notothenia rossii and Champsocephalus gunnari, with nominal catches weighing 16,204 (85%) and 876 kg (5%), respectively. Other species of fish accounted noticeably for lower amounts (11%), such as Gobionotothen gibberifrons (330 kg), Chaenocephalus aceratus (322 kg), and Pseudochaenichthys georgianus (299 kg). Indicative estimates of standing stock biomass suggested that in this cruise, N. rossii was the most abundant demersal finfish species in the Elephant Island area, followed by C. gunnari. Differently, on the South Orkney Islands shelf, the most abundant species was G. gibberifrons, followed by P. georgianus. The study provides biological data (length frequency distribution, median size, sex ratio, gonad maturity stages, length-weight relationship) on the main species captured during the survey, and the oceanographic characteristics (depth profiles of temperature, salinity, density) obtained with CTD around the South Orkney Islands. <![CDATA[Compelling palatability of flavoring Atractus AQVA<sup>®</sup> for Nile tilapia juveniles]]> ABSTRACT This study determined the compelling palatability of Atractus Aqva® flavoring for Nile tilapia juveniles (Oreochromis niloticus). Five isoproteic (40% crude protein) and isoenergetic (3,420 kcal kg-1) experimental diets were elaborated containing 0.25 (A25), 0.50 (A50) and 0.75% (A75) flavoring inclusion, a positive control diet with 10% fishmeal (FPE) and a negative control without fishmeal (SPE). Five juvenile individuals (2.58 ± 0.27 g) were distributed in five 10 L tanks and were fed four times a day with one of the diets, randomly raffled. The same number of pellets was offered, and the following behaviors were observed: time to capture the first pellet, number of pellet rejections, and number of approximations without capture and consumed pellets in each feeding event, using three-minute recordings with a digital camera. A significant effect (P &lt; 0.05) was found regarding the number of approximations without capturing the pellet, as well as a higher palatability index for A75, followed by A50, A25, SPE and FPE. Therefore, it was concluded that A75 provided the highest compelling palatability of all diets by increasing the palatability index by 10.49% and displaying a 23.13% reduced rejection of pellets, besides presenting a 3.3 fold reduction in the number of approximations without capturing pellets with diet FPE. <![CDATA[Screening of Chilean fish-killing microalgae using a gill cell-based assay]]> ABSTRACT Fish-killing algal species are responsible for important global economic losses to the finfish industry. Chile is the world’s second-largest salmon exporter, and fish-killing algal blooms have widely impacted its production in the last decades. The lack of standardized analytical methods to quantify and characterize the so-called “ichthyotoxins” has hindered our understanding of the underlying ichthyotoxic modes of action. The novel application of a highly sensitive and reproducible fish RTgill-W1 cell line-based assay has allowed significant progress in the field. In this study, the ichthyotoxic potency of the main microalgae species, which has been reported in fish-killing events in the historical Chilean monitoring programs, was assessed. The dinoflagellate Karenia selliformis was the most ichthyotoxic species against the RTgill-W1 (cell viability down to 8%), representing the major threat for the local salmon industry. In comparison, the raphidophyte Heterosigma akashiwo and the dinoflagellate Prorocentrum micans were the least toxic (gill cell viability down to 81 and 89%, respectively). Importantly, ichthyotoxic flagellates were more toxic to fish gill cells upon rupture. These results have important implications for the mitigation and management of algal blooms by the salmon industry. <![CDATA[Does protein content influences accumulation and biomagnification of tantalum in fishes and invertebrates of marine coastal environments?]]> ABSTRACT Tantalum (Ta) is a rare transition metal widely used in the manufacture of new technologies such as computers, cell phones, solar panels and implants in biomedicine, and their use is continuously increasing. Most non-essential metals are immobilized in the organism through complexation with proteins, but it is not known if new-technology elements (such as Ta) present the same behavior. In aquatic environments, metals tend to concentrate in biota and some can be biomagnified through the trophic chain, even reaching humans. This study aimed to investigate any possible relationship between Ta and proteins. Invertebrates and fishes were collected from coastal marine ecosystems of northern Chile, Patagonia, and South Shetland Islands (Antarctic Peninsula). A direct positive relationship was found between Ta and total proteins throughout the food chain from marine ecosystems of the Patagonia and the Antarctic Peninsula area, revealing that proteins are probably the pathway by which Ta bioaccumulates and biomagnifies in macroinvertebrates and fish of pristine coastal marine environments. Our data suggest that site-specific factors (e.g., water temperature, pH, geography) may be influencing the environmental fate of Ta. Therefore, further studies are needed to understand the biological implications of this metal.