Shrimp larval feed success depends not only on nutritional profile but also on its physical characteristics, and one of these properties is particle size. However, no clear criteria exist for selecting the appropriate size for each larval stage. Feed particle size significantly impacts shrimp growth performance and feed production costs. Therefore, the present study evaluates the effect of particle size on feed consumption in Penaeus vannamei larvae and early postlarvae. The extruded diet was crumbled and sieved into the following size ranges: <53, 53-106, 106-150, and 150-250 mu m, and fed to larvae and early postlarvae for 30 min. Organismal feed particle size preference was determined using the feeding efficiency (FE) index (FE = feeding incidence & times; gut fullness). Feeding incidence values indicate that larvae from Protozoea III to Postlarvae 6 had the capacity to identify, capture, and ingest feed particles from <53 to 250 & micro;m - no significant effect was detected by particle size. In contrast, particle size had a significant effect (P < 0.05) on feed intake, as indicated by gut fullness values. Larval stages had a greater ingestion capacity of particles smaller than 150 & micro;m, while early postlarval stages showed increased gut fullness when fed on particles larger than 150 & micro;m. In general, based on the FE results, feed particle sizes smaller than 150 & micro;m are recommended for larval stages, and 150-250 & micro;m for early postlarvae.
Dolphinfish (Coryphaena hippurus) is an important target species for the sport-fishing fleet in the southern Gulf of California, Mexico. However, little is known about its spatial distribution, primarily due to the lack of georeferenced data. The main objectives of this study were to evaluate the effect of environmental variability on nominal catch rates (CRs) of dolphinfish and to infer their spatiotemporal distribution. The data used in this study includes the number of individuals caught and the geographic coordinates recorded by one of the main sport-fishing fleets operating out of Cabo San Lucas, Mexico. Generalized additive models were applied to explore the complex, non-linear effects of environmental (temperature and chlorophyll-a), physical (depth), spatial, and temporal (year-month) variables on CRs. The results suggest that sea surface temperature, location, depth, and temporal factors significantly influence dolphinfish CRs in the study area. Specifically, higher CRs are expected along the western coast in shallow warm waters during the summer-autumn period (August to November).
Historically, scientific records of great white sharks (Carcharodon carcharias) in the Gulf of Mexico have been rare; however, on January 24, 2024, a subadult male was captured in Tamiahua, Veracruz, Mexico. The specimen measured 353 cm in total length and weighed 411.9 kg, which complements the reported presence of females of the species in other regions of the Gulf of Mexico. Although capture records suggest the species is rare, local ecological knowledge from fishermen indicates that specimens were captured in previous years. The presence of C. carcharias in this region may be associated with the fact that, in other areas (e.g. Mexican Pacific), individuals of similar size tend to remain near the continental shelf. This record is the first officially documented record of a subadult male of C. carcharias in the region. This finding expands our knowledge of the species' dynamics in the Gulf of Mexico, suggesting that, as in the Mexican Pacific (Guadalupe Island), the Veracruz coast plays a key role in the conservation of this endangered vulnerable species.
. This study aimed to describe the mass mortality of farmed Nile tilapia (Oreochromis niloticus) associated with co-infections during summer in Sinaloa, on the northwest coast of the Mexican Pacific. In July 2023, a parasitic infection occurred at a Nile tilapia farm, coinciding with an increase in water temperature and a decrease in dissolved oxygen, resulting in fish mortality. The fish farmers applied treatments to eliminate the infection and halt the deaths; however, fish continued to die for several days. Thirty moribund fish were collected for laboratory examination and histopathological analysis. The fish showed signs of emaciation, lethargy, and skin abrasions. Parasitological analysis identified ectoparasites, the most abundant of which were peritrichous ciliates on the gills and the host fish's epithelium. Five species were identified: Trichodina hypsilepis, T. magna, T. nigra, Trichodina sp., Ambiphrya sp., and one unidentified protozoan. The monogeneans Gyrodactylus cichlidarum and Ciclydogyrus sp. were identified, as well as Pseudomonas sp. (probably as a secondary agent). Histopathological examination of the fish gills showed that the protozoan attached to the gill filaments caused severe hyperplasia and gill epitheliocystis. The mortality event lasted 10 days, reaching 50,000 deaths (5,000 dead fish per day). Parasitic infections have significant consequences for farmed fish species and should be considered a fundamental factor in any aquaculture system.
Waves are the primary phenomenon to be considered in coastal engineering studies and designs, as they constitute the primary source of energy driving coastal flows and processes. This study examines the roles of gravity (G) and infragravity (IG) waves in suspended sediment transport within the surf zones of two Caribbean beaches in Colombia: the reflective-intermediate beach, Costa Verde, and the dissipative-intermediate beach, Bocagrande. Field measurements included free-surface elevation (eta), cross-shore (u) and alongshore (v) velocities, and sediment corrected backscatter (SCB, in dB). Results indicate higher sediment suspension during the dry season, with IG wave energy dominating cross-shore and alongshore currents. Strong correlations between u and v components and SCB, revealed by Cross Wavelet Transform (XWT) and Wavelet Transforms Coherence (WTC), show that IG waves largely control sediment flux. Energy and SCB fluxes did not exhibit a uniform direction, reflecting complex interactions with beach morphology, wave breaking, and anthropogenic structures. Overall, IG-driven currents are the primary factor controlling suspended-sediment transport and morphodynamic evolution in the surf zone. These findings provide essential insights for coastal management and the planning of erosion-mitigation measures for urban beaches.
Plastic pollution is a growing environmental concern, with macroplastics posing significant risks to human and animal health. However, despite increasing global attention, there remains a limited understanding of how research on macroplastic pollution has evolved across Latin America in marine and freshwater ecosystems. This study aims to conduct a scientometric review of macroplastic research in Latin America, identifying trends, gaps, and opportunities for future studies. A systematic search was conducted in Web of Science, Scopus, and SciELO databases, using bibliometric tools such as Bibliometrix and VOSviewer to analyze publication trends. Mann-Kendall and Pettitt's tests indicated a significant increase in the number of publications on macroplastic pollution in Latin America since 2013, which may be linked to the rise of global policies aimed at reducing plastic use due to its environmental impact. A total of 206 relevant studies were identified, with Marine Pollution Bulletin being the most prominent journal in this field. Research on macroplastic pollution was primarily conducted in marine coastal beaches (56.6%) and marine islands (12%), while freshwater ecosystems (7.2%) remained underrepresented. Few studies have explored trophic transfer, plastic fragmentation, or macroplastic ingestion by non-marine species. Our findings highlight the need to expand macroplastic research in Latin America, particularly in river and stream systems, which remain critically understudied. Future work in the region should extend sampling beyond beaches into inland and deep-sea environments, integrate hydrological context, incorporate multiple plastic size fractions within unified sampling designs, broaden taxonomic coverage, evaluate policy effectiveness, and strengthen citizen-science initiatives in inland waters to support evidence-based decision-making.
This study aimed to determine the population dynamics (size, weight, growth, and mortality) of the rock oyster Striostrea prismatica (Gray, 1825) settled in two different environments: the shallow rocky sublittoral of Faro de Campos and the Cuyutlan lagoon (Colima, Mexico). The oysters from Faro de Campos (coastal site) recorded greater size and weight than in the lagoon site. Analysis of the length-frequency distribution showed five modal groups in the overall population, four in the lagoon, and only three at the coastal site. The length-weight ratio indicated negative allometric growth in the oysters at both sites. Although the asymptotic length or infinite height (H-infinity) and growth coefficient (k) were similar in the lagoon (H-infinity = 176 mm; k = 1.3 yr(-1)) and in the coastal site (H-infinity = 174 mm; k = 1.06 yr(-1)), the lagoon oysters reach maximum length in less time than those on the coast. Mortality indicators showed signs of overexploitation on both sites, particularly in the lagoon (exploitation rate, E = 0.62), and at the upper limit of population exploitation at the coastal site (E = 0.5). This information is relevant for the sustainable management of the species in the Mexican central Pacific.
. This study evaluated the immunostimulatory and protective effects of a multispecies probiotic formulation -comprising Bacillus subtilis, Lactobacillus plantarum, and Pediococcus acidilactici- on juvenile Colossoma macropomum reared in biofloc and recirculating aquaculture systems over 70 days. The probiotic was administered via feed, water, or both, and its effects on growth performance, hematological and biochemical profiles, innate immune responses, and resistance to Aeromonas hydrophila infection were assessed. The combined probiotic strategy (feed + water) led to enhanced weight gain, improved serum lysozyme and protease activity, and higher reactive oxygen species production. Fish reared in biofloc systems exhibited higher hematocrit, hemoglobin, and innate immune markers than those reared in recirculating systems. However, recirculating aquaculture systems yielded superior growth and survivability. Following bacterial challenge, the combined probiotic treatment achieved 100% survival in the biofloc system, while the control group showed 50% survival. These findings highlight the potential of multispecies probiotics to improve immune competence and disease resistance in tambaqui, supporting their use as sustainable biotechnological tools in aquaculture. The choice of probiotic administration route and farming system significantly influenced host physiology and response to bacterial infection. Importantly, probiotic supplementation may serve as a viable alternative to antibiotics, reducing the risk of antimicrobial resistance and promoting more sustainable fish farming practices.
The El Soldado coastal lagoon in Sonora, Mexico, is a protected natural area and a Ramsar site; hence, fishing and aquaculture activities have been prohibited there since 2006. Considering its excellent state of conservation, it serves as a model for comparative studies with other coastal lagoons of the Gulf of California that are more heavily impacted by human activity. Therefore, it is essential to describe its biodiversity and emphasize the importance of its conservation. El Soldado has several species of mollusks; however, only two oyster species have previously been reported, which underestimates the diversity of the Ostreidae family in that area. This study was conducted to determine the species of ostreids inhabiting this coastal lagoon and to corroborate anatomical identification using molecular tools. The following four oyster species were found: the mangrove oyster Saccostrea palmula, the pleasure oyster Crassostrea corteziensis, the flat oyster Ostrea angelica, and the rock oyster Striostrea prismatica. However, some S. palmula specimens showed mitochondrial sequences and a nuclear region of Magallana gigas (= Crassostrea gigas), representing a threat to the evolutionary legacy of the S. palmula genome, and the magnitude of the impact at the population level and in other nearby coastal lagoons where M. gigas is cultured remains to be addressed.
The yaque catfish, Leiarius marmoratus, is a native South American fish with characteristics that make it a promising species for aquaculture; however, its nutritional requirements at any developmental stage remain unknown. To determine the protein requirement for juveniles of L. marmoratus and evaluate the protein-sparing effect by increasing dietary energy, a feeding experiment was conducted with five levels of crude protein in the diet (22, 28, 34, 40, and 47%) and two energy levels (3,400 and 3,750 kcal metabolizable energy kg(-1) diet). A total of 450 yaque fingerlings weighing 0.80 +/- 0.1 g were used, randomly distributed in 30 tanks (15 fish tank(-1)), fed to apparent satiation twice daily for 60 days. Zootechnical performance parameters were determined: weight gain (WG), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), condition factor (K), and survival (S). Final weight, WG, K, and PER were influenced by protein level (P < 0.05), but not by energy level. Significance was detected in the protein-energy dietary interaction. Feed intake, FCR, and SGR were not significantly affected by energy level (P > 0.05) but were affected by protein level (P < 0.05). The protein-sparing effect was evident when the energy level increased from 3,400 to 3,750 kcal kg(-1). The protein requirement for juvenile yaque, determined by a second-order polynomial regression model, is between 38.1 and 42.0% crude protein, depending on the energy level present in the diet.
The present work evaluated the combination of biopolymers used as preservative agents to enhance the viability and efficacy of the vB_Pd_PDCC-1 phage stored as a powder under high-temperature conditions. In the tests, phages were freeze-dried in a polymeric matrix with varying molar ratios of sodium alginate, gelatin, and trehalose, stored at 4, 25, 35, and 45 degrees C, and evaluated at 1, 30, 60, and 90 days post-freezedrying. The results indicated that the best treatment was the combination of trehalose (4% w/v) and gelatin (1.5% w/v), as it maintained phage viability (log 6) for up to 90 days at 45 degrees C. Likewise, phage therapy trials using Artemia nauplii inoculated with Vibrio diabolicus and lyophilized phages embedded in biopolymeric matrices showed survival rates similar to those of the control group, reducing bacterial concentration by 3 log orders of magnitude. The study identified the combination of trehalose and gelatin as a promising additive mixture for protecting the powdered bacteriophage Pd_PdCC-1.
Chlorophyll-a (Chl-a) is widely regarded as a proxy for phytoplankton biomass. In marine environments, the concentration of Chl-a and its vertical and horizontal distributions are closely linked to the water column hydrography and nutrient availability. This study aimed to assess the spatial distribution of Chl-a in the deep waters of the southern Gulf of Mexico and evaluate its relationship with hydrography and nutrient concentrations during the summer season. A multidisciplinary research cruise was conducted in August and September 2018 to collect high-resolution hydrographic data and water samples at various depths (surface, 10, 20, 50, 100, and 150 m). These samples were analyzed for nutrient content and Chl-a concentration. The results revealed significant horizontal and vertical variability. Notably, a low-temperature, high-density core was identified at 50 m depth, indicating the presence of a cyclonic eddy. Within this cold, dense core, nutrient levels increased, while Chl-a concentrations peaked at depths of 50 m and below. Principal Component Analysis confirmed that temperature and nutrients were the primary drivers of Chl-a concentrations, particularly at 50 m depth, and below. While previous research has explored Chl-a distribution in the southern Gulf of Mexico, few studies have used in situ observations to examine deeper regions. This study demonstrates how hydrographic conditions regulate nutrient and Chl-a dynamics in an area where deep-water sampling remains operationally and economically challenging.
Sea temperature anomaly events play a fundamental role in the environmental variability within the Eastern Pacific Ocean (EPO). However, the magnitude and spatial extent of these events should be acknowledged, as they are not uniform across all areas. A comprehensive understanding of this variability is necessary for regional analyses. The present study used sea surface temperatures (SST; 2000-2020) from the Global Ocean Ensemble Physics Reanalysis database to represent the spatial distribution of SST anomalies within the EPO during four intense El Ni & ntilde;o Southern Oscillation (ENSO) events. Additionally, time series of anomalies based on the Extended Reconstructed Sea Surface Temperatures database were obtained for uniformly selected quadrants along the EPO, as well as for its main currents and water masses. The findings revealed significant differences between prominent ENSO events and certain EPO areas: the central EPO showed a higher frequency, whereas others, such as the Costa Rica Dome, showed a lower frequency, particularly during La Ni & ntilde;a events. Furthermore, the present study identified disparities when comparing the outcomes reported by the main El Ni & ntilde;o regions widely used for ENSO identification. For instance, while La Ni & ntilde;a 2000/01 and El Ni & ntilde;o 2002/03 were identified by the Oceanic El Ni & ntilde;o Index and the El Ni & ntilde;o 3 and El Ni & ntilde;o 4 indices, these events were not observed in all the EPO. Likewise, certain events showing clear warm-anomaly trends, such as those in 2017/18, were classified by the indices as cold periods. In contrast, strong events such as La Ni & ntilde;a 2010/11 and El Ni & ntilde;o 2014/16 were consistently identified in all selected areas in the EPO, in coincidence with the indices.
Seabirds are important biological pathways, moving pollutants from sea to land via their guano and feathers. This study investigated the influence of Humboldt penguin nesting activities on trace element concentrations in soils at Pajaros Ninos Islet, central coast of Chile. Soil samples were collected from penguin nesting sites and control areas during July 2022 and analyzed for seven trace elements (Pb, Cu, Co, Cr, Zn, Ni, and As) using inductively coupled plasma optical emission spectroscopy (ICP-OES). Lead concentrations were significantly higher in nesting sites compared to control sites (3.57 +/- 0.64 vs. 2.66 +/- 0.70 mg kg(-1), P < 0.05), while Cu, Zn, and Ni showed elevated but non-significant concentrations in nesting areas. The trace element hierarchy in nesting sites was Zn > Cu > Cr > Pb > As > Co > Ni, differing from typical crustal abundance patterns. Spearman correlation analysis revealed a strong positive correlation between Cu and Zn (r = 0.93, P < 0.01) and a moderate correlation between Co and As (r = 0.83, P < 0.05) in nesting sites. Principal component analysis revealed considerable overlap among site types, suggesting subtle geochemical differences. These findings suggest that while Humboldt penguins influence soil trace element composition through guano inputs, the magnitude of change is modest compared to natural variation. The results contribute to understanding seabird-mediated biotransport of trace elements and highlight the need for further research on the ecological implications of metal accumulation in coastal nesting habitats.
The decline in fishery production has driven technological changes and increased fishing effort, threatening sustainability. On the Campeche Bank, artisanal vessels have been modified to enhance their autonomy and their capacity to catch grouper and associated species. These vessels are converted into "lanchones" Athrough transverse, longitudinal, or combined cuts to extend their overall length and beam, followed by raising the gunwale and molded depth. These vessels are not regulated under Mexican law, and their operational dynamics are unknown. The analysis reveals that their average catch volume is comparable to that of the semi-industrial fleet. Still, their species composition is similar to that of the artisanal fleet, positioning them with an operational profile between both fishing segments. However, they use more hooks than either fleet, amplifying fishing effort. While the selectivity of the fishing gear surpasses the minimum legal catch size for red grouper, factors such as depth and hook size also influence this outcome. Given that the red grouper population is considered overexploited, it is crucial to assess the impact of these vessels and strengthen regulatory measures to ensure the sustainability of both the resource and fishing activities.
Although muricid snails are an important ecological and fisheries resource in northwest Mexico, information on their allometry and morphometry is scarce. For one year (February 2022-January 2023), 30 specimens of the "Chinese black" snail, Hexaplex nigritus (shell height = 101.4 +/- 13.7 mm, total snail weight = 192.3 +/- 89.1 g) were monthly collected from a coastal lagoon of the southeastern Gulf of California. The biometrics of shells (height SH, length SL, width SW, and shell opening width WSO) and operculum (height OH, length OL, and width OW) and weight variables (total snail weight TWS, total hell weight TSW, total tissue weight TTW, total gonad weight TGW, and total operculum weight TOW) of sampled snails were morphometrically analyzed. All biometric indicators of the snail shell and operculum showed significant differences (P < 0.05) monthly and presented linear and positive equations in all associations. The SH/SL relationship represents the most appropriate tool to describe the relative growth of this gastropod (coefficient of determination, R-2 = 0.80), considering an empty shell; meanwhile, TWS/SL better describes the shell/weight interaction (R-2 = 0.80) for live snails. The water temperature showed a positive correlation with the biometric indicators. The measurements obtained from the shell dimensions of this gastropod indicate that the sampled population consisted of adult snails. These data are fundamental for the management and conservation of this muricid species in the study area, providing valuable information for planning sustainable management strategies.
. Mealworm (MW) from the red wriggler, Eisenia fetida, has been used as a dietary substitute or complement in aquaculture diets. However, the substrate in which it is cultivated varies its proximate composition. This study aimed to evaluate the inclusion of MW produced in two substrates-vegetal culture (VC) and animal culture (AC)-in mixed diets for juvenile Penaeus vannamei. A 2 & times;3 factorial experimental design was used, consisting of two substrates (VC and AC) and three inclusion levels (5, 10, and 20%), yielding six diets, each with three replicates. Shrimp (2.29 +/- 0.13 g) were cultured for 75 days in a recirculating system and were fed twice daily. Growth performance, survival, and digestive enzyme activity were evaluated. Shrimp fed with 10% VC showed a higher final weight (8.07 +/- 0.39 g) and weight gain (5.66 +/- 0.45 g) (P < 0.05) at the end of the experiment. The final weight, weight gain, and specific growth rate were higher in organisms fed with VC, regardless of the inclusion level. Survival was similar (>90%) across all treatments (P > 0.05). Except for lysine, the levels of essential and nonessential amino acids increased with the MW substitution level produced using both substrates. Both 10% VC and 10% AC groups showed the highest digestive protease activity (39.83 +/- 3.0 and 50.87 +/- 4.4 U mg protein-1 in VC and AC, respectively). In contrast, the highest chymotrypsin activity was observed in the 5% AC group (6.08 +/- 0.43 U mg chymotrypsin-1). The results indicate that incorporating MW from E. fetida, produced on either substrate, into a mixed diet alters shrimp growth and enzymatic activity without affecting survival. However, future studies evaluating MW as an ingredient in formulated shrimp feeds should proceed with caution, particularly regarding the characteristics of the worm-culture substrate.
This study reports the first occurrence of xanthism in captive juveniles of the leopard grouper Mycteroperca rosacea, a species of high ecological and commercial value in the Gulf of California. One hundred fifty individuals (mean +/- standard deviation: 106.1 +/- 36.7 g; 19.5 +/- 2.3 cm) were reared from eggs obtained at the Centro de Investigaciones Biol & oacute;gicas del Noroeste (CIBNOR, La Paz, Mexico) between March and October 2009. Changes in body coloration from the normal brown pattern to a yellow (xanthic) phenotype were observed on five separate occasions during this period. The transition began in the dorsal and ventral regions and extended to the flanks and caudal fin, eventually covering the entire body surface. These findings provide the first documentation of xanthic pigmentation in M. rosacea under controlled aquaculture conditions and highlight the potential influence of genetic, environmental, and dietary factors on colour expression in this species.
This study evaluated alternative carbohydrate sources available in the Brazilian Amazon for use in biofloc systems for the cultivation of white shrimp (Penaeus vannamei). The motivation stems from the limited accessibility in this region of sugarcane molasses, a conventional carbon source for the production of bioflocs. Four sources of carbohydrates were tested: coffee grounds, cassava meal, tapioca starch, and molasses, for 35 days. Juvenile shrimp (initial weight 0.14 g) were stocked at a density of 300 ind m(-3) in 12 70-L polyethylene tanks, across four treatments with three replications. The effects of the springs on water quality, zootechnical performance of shrimp, and centesimal composition of biofloc and animals were evaluated. All sources maintained water quality within the recommended range for the species. However, the molasses treatment resulted in significantly higher zootechnical performance, with a final weight of 0.61 g and a weekly gain of 0.09 g (P < 0.05). Regarding composition, only moisture content varied significantly between treatments, and coffee grounds and molasses differed from cassava meal and tapioca gum. In addition, shrimp produced with coffee grounds differed significantly from those treated with tapioca gum. In conclusion, although molasses yielded the best performance, all alternative sources also proved efficient. The results show the potential of regional inputs as viable alternatives, expanding the applicability of biofloc technology in areas where molasses is not readily available, contributing to the consolidation of aquaculture practices adapted to Amazonian conditions, and promoting greater productive and environmental autonomy in the activity.
Optimum feed ratio and frequency ensure maximum growth and efficient feed utilization across feeding management strategies. The present study evaluated the effects of feeding frequency and ration restriction on Penaeus vannamei juveniles (0.8 +/- 0.06 g) fed two diets over 53 days. Feeding frequency included two (10:00, 16:00 h) and four times a day (10:00, 16:00, 22:00, 04:00 h), using isonitrogenous diets (35% protein) formulated with fish hydrolysates produced via external (FHEE) or internal (FHIE) enzymes. Feed was supplied at 100 and 80% of apparent satiation. At the end of the experiment, survival was not different among treatments (P > 0.05). Shrimp fed twice showed a significantly higher weight gain than those fed four times (6.27 +/- 0.43 vs. 5.76 +/- 0.38 g, respectively); no significant difference (P > 0.05) in feed conversion ratio (FCR) was found between two and four times a day treatment at 100% ration size. However, feed efficiency was significantly affected by feeding frequency (P < 0.05) at 80% of apparent satiation, with four daily feedings showing improved FCR (1.55 +/- 0.07) compared to two feedings per day (1.73 +/- 0.08). The results demonstrated improved feed efficiency at 80% satiation compared with 100% satiation (FCR = 1.64 +/- 0.07 vs. 1.93 +/- 0.12, respectively), at the expense of growth (5.79 +/- 0.31 vs. 6.23 +/- 0.51, respectively). No differences in weight gain were observed between the distinct diet types (FHEE or FHIE). The results highlight the significant impact of ration size and feeding schedules, demonstrating that restricted rations (80%) improve feed efficiency at the expense of growth and that increasing feeding frequency at night does not provide additional benefits compared to daytime feeding.
