Feeding Habits of Dwarf Goatfish (Upeneus parvus: Mullidae) on the Continental Shelf in the Gulf of Mexico

Feeding habits of dwarf goatfish on the continental shelf off Alvarado, Veracruz, Mexico, were analyzed to determine seasonal variation and size-class changes in diet composition and trophic overlap between size classes. Food was found in 63% of the 1,437 dwarf goatfish guts analyzed. The 52 dietary items identified consisted mainly of crustaceans, with Solenocera vioscai being the most important prey. Dwarf goatfish exhibited seasonal and size-class changes in prey consumption. Despite the high number of prey items, low values of diversity and diet breadth were found in the trophic spectrum. A high trophic overlap between size classes was observed in the north-winds season between length classes (92-111 vs 112-130 mm) (λ = 0.81) and (92-111 vs 131-150 mm) (λ = 0.80), and (112-131 vs 131-150 mm) (λ = 0.67). In the rainy season high overlaps were obtained between (92-111 vs 112-131 min) (λ = 0.73) and (112-131 vs 131-150 mm) (λ = 0.84) length classes. Dwarf goatfish appear to be opportunistic carnivorous predators that impact benthic and epibenthic invertebrates

Seasonal and diel influences on bottlenose dolphin acoustic detection determined by whistles in a coastal lagoon in the southwestern Gulf of California

Marine mammals in subtropical coastal habitats are sentinels of the health of the ecosystem and offer important ecosystem services. They rely on prey that pursues feeding opportunities, while both avoid unfavorable conditions. In many cases, these predator-prey dynamics fluctuate seasonally and are regulated by lunar, tidal, and/or diel cycles (hour). However, these rhythmical patterns may vary under different seasonal conditions. Bottlenose dolphins (Tursiops truncatus) in the Ensenada de La Paz in Baja California Sur, Mexico, were detected acoustically over the course of an annual cycle on 21 separate occasions, covering 640 h from June 2017 to May 2019. The presence of bottlenose dolphins was examined using Generalized Additive Models (GAM) including variables that are related directly to their habitat (direct variables: hour, distance, depth) and to their prey (indirect variables: SST, moon phase and tides). Seasonal differences in the presence of bottlenose dolphins were influenced more by indirect variables (explained deviance: 34.8% vs. 37.7%). Hourly acoustic detections occurred less frequently when SST exceeded 27.4 °C (Aug–End of Nov.) and more frequently at moderate temperatures (22.7 °C to 26.3 °C) in May through July. Moreover, bottlenose dolphins were detected more frequently during waning and new moon phases, at the onset of flood and ebb tides, and during day (04:00 to 20:00). The seasonal differences in acoustic detections rates were highlighted by the global GAM and hierarchical clustering. The strong seasonal pattern indicated possible interactions with rhythmic pattern of bottlenose dolphins. Four candidate variables (SST, moon, tide, and hour) were tested for plausible interaction terms additional to their individual consideration, out of which only hour changed significantly between seasons. The patterns of presence likely increase feeding opportunities or may favor other behaviors such as socializing, resting, or nursing. These might prove responsible for the distinct occurrence and hourly patterns of bottlenose dolphins.</p

Comparison of ecological diversity and species composition of macroalgae, Benthic macroinvertebrates, And fish assemblages between two tropical rocky reefs [Comparaci�n de la diversidad ecol�gica y composici�n de especies de ensambles de macroalgas, Macroinvertebrados bent�nicos y peces en dos arrecifes rocosos tropicales]

Within the marine environment, the rocky shores are recognized for their high species diversity and particularly transitional zones represent areas of biotic mix, promoted by historical and ecological natural variations that allow the presence of taxa from different regions and which present dissimilar biological traits. An extensive survey describes the benthic macroalgae, macroinvertebrates (molluscs, crustaceans, and echinoderms), and fish assemblages at two rocky reefs, Islas Marietas and near Tehuamixtle, in a tropical-temperate transitional zone in the Pacific waters of central Mexico using traditional ecological indices (richness, diversity, and evenness) and complementary taxonomic distinctness indices. Biological material inside each of ten randomly-chosen quadrants (25 � 25 cm) placed along two 50 m transects oriented parallel to the coastline, between 6 and 2 m depth was collected. From field collections, 204 species were identified: macroalgae (22), molluscs (55), crustaceans (78), echinoderms (11), and fish (38). The structure of macroalgae, macroinvertebrates and fishes was similar between sites. Species of macroalgae, molluscs, and fishes were more diverse in summer; crustaceans and echinoderms were more diverse in winter. Our results and the literature suggest a latitudinal pattern of lower seasonal changes in echinoderms and crustaceans at high latitudes, as compared to southern regions of the Mexican tropical Pacific. � 2014 Universidad de Valparaiso. All rights reserved

Comparison of ecological diversity and species composition of macroalgae, Benthic macroinvertebrates, And fish assemblages between two tropical rocky reefs [Comparación de la diversidad ecológica y composición de especies de ensambles de macroalgas, Macroinvertebrados bentónicos y peces en dos arrecifes rocosos tropicales]

Within the marine environment, the rocky shores are recognized for their high species diversity and particularly transitional zones represent areas of biotic mix, promoted by historical and ecological natural variations that allow the presence of taxa from different regions and which present dissimilar biological traits. An extensive survey describes the benthic macroalgae, macroinvertebrates (molluscs, crustaceans, and echinoderms), and fish assemblages at two rocky reefs, Islas Marietas and near Tehuamixtle, in a tropical-temperate transitional zone in the Pacific waters of central Mexico using traditional ecological indices (richness, diversity, and evenness) and complementary taxonomic distinctness indices. Biological material inside each of ten randomly-chosen quadrants (25 × 25 cm) placed along two 50 m transects oriented parallel to the coastline, between 6 and 2 m depth was collected. From field collections, 204 species were identified: macroalgae (22), molluscs (55), crustaceans (78), echinoderms (11), and fish (38). The structure of macroalgae, macroinvertebrates and fishes was similar between sites. Species of macroalgae, molluscs, and fishes were more diverse in summer; crustaceans and echinoderms were more diverse in winter. Our results and the literature suggest a latitudinal pattern of lower seasonal changes in echinoderms and crustaceans at high latitudes, as compared to southern regions of the Mexican tropical Pacific. © 2014 Universidad de Valparaiso. All rights reserved

Разработка технологических процессов создания экспериментальных образцов сенсорных электронных компонентов на основе углеродных нанотрубок: отчет о НИР (заключ.)

Разработаны технологические процессы создания чувствительных элементов датчиков механических величин на основе массивов углеродных нанотрубок, осаждаемых в процессах химического парофазного синтеза на полимерные подложки. Разработаны технологические процессы функционализации и интеркаляции для чувствительных элементов датчиков на основе массивов углеродных нанотрубок, выполнена оптимизация технологических процессов создания и исследованы образцы сенсорных электронных компонентов на основе модифицированных углеродных нанотрубок

Long term changes in the fish fauna of Lago de p�tzcuaro in central M�xico [Cambios a largo plazo en la fauna de peces del lago de p�tzcuaro en M�xico central]

Fish assemblages of lakes from central M�xico have been altered as a result of water over-exploitation, pollution, habitat fragmentation, and introduction of exotic species. Patterns and the extent of change in most of these systems are poorly documented. This paper presents a long-term study of changes in the fish fauna of Lago de P�tzcuaro (State of Michoac�n, M�xico). Long-term information (years 1900-2010) of fish communities was used to explore trends in the composition of the fish community and their ecological attributes. Trends across time for each fish guild were evaluated through a multivariate analysis of variance. Native species dominated total species richness over the entire study period, but exotic fish comprised 46% of the community in the 2010s. During the last 110 years, there has been a decline in the number of carnivore species and an increase of omnivore species in the Lago de P�tzcuaro fish community. Sensitive species have disappeared from the lake and species tolerant to environmental degradation have increased from 13 to 61%. The data suggest that anthropic effects on the environmental condition of Lago de P�tzcuaro are associated with the loss of ecosystem elements (fish species) and ecosystem processes (species interactions). Ecological restoration and conservation programs must include information of these long term studies to be more effective in their efforts

Long term changes in the fish fauna of Lago de pátzcuaro in central México [Cambios a largo plazo en la fauna de peces del lago de pátzcuaro en México central]

Fish assemblages of lakes from central México have been altered as a result of water over-exploitation, pollution, habitat fragmentation, and introduction of exotic species. Patterns and the extent of change in most of these systems are poorly documented. This paper presents a long-term study of changes in the fish fauna of Lago de Pátzcuaro (State of Michoacán, México). Long-term information (years 1900-2010) of fish communities was used to explore trends in the composition of the fish community and their ecological attributes. Trends across time for each fish guild were evaluated through a multivariate analysis of variance. Native species dominated total species richness over the entire study period, but exotic fish comprised 46% of the community in the 2010s. During the last 110 years, there has been a decline in the number of carnivore species and an increase of omnivore species in the Lago de Pátzcuaro fish community. Sensitive species have disappeared from the lake and species tolerant to environmental degradation have increased from 13 to 61%. The data suggest that anthropic effects on the environmental condition of Lago de Pátzcuaro are associated with the loss of ecosystem elements (fish species) and ecosystem processes (species interactions). Ecological restoration and conservation programs must include information of these long term studies to be more effective in their efforts

Trophic interrelations between introduced common carp, Cyprinus carpio (Actinopterygii: Cypriniformes: Cyprinidae), and fish community in a eutrophic shallow lake

Background. Introduction of the common carp, Cyprinus carpio Linnaeus, 1758, may cause a cascade of alterations in trophic webs, among other negative effects, indirectly due to its feeding behaviour. A simplified model site, covenient for studying such interrelations is Lago de Pátzcuaro, México, a shallow lake where carp was first introduced in 1974. The aim of our study was to characterize diet composition, diet breadth and trophic position of C. carpio and local fish fauna, and to assess diet overlap between fish fauna from sites with different habitat characteristics during the wet and the dry seasons. Materials and methods. We assessed the diet of C. carpio and local fish fauna in six sites during the wet and the dry seasons. Stomach content analysis was carried out separately for each length class. The importance of each item was estimated by the index of relative importance (IRI) and the omnivory index was used to assess the feeding behaviour. The trophic guild and trophic position were determined using the TrophLab software and stable isotope analysis. Diet breadth was calculated by Levin’s Index and diet overlap by the Horn’s Index. Fish dorsal muscle and water hyacinth tissues were obtained from nitrogen isotope signature analysis. Results. We found that C. carpio is an omnivorous fish that feeds in shallow areas with water hyacinth cover and rooted macrophytes, consuming mainly detritus and plant debris (>60%). However, δ 15N values indicate that C. carpio is also a secondary consumer because it also ingests invertebrates associated with plant debris. The carp diet overlaps with native blackfin, Goodea atripinnis Jordan, 1880, at most sites. Small carp

Trophic interrelations between introduced common carp, Cyprinus carpio (Actinopterygii: Cypriniformes: Cyprinidae), and fish community in a eutrophic shallow lake

Background. Introduction of the common carp, Cyprinus carpio Linnaeus, 1758, may cause a cascade of alterations in trophic webs, among other negative effects, indirectly due to its feeding behaviour. A simplified model site, covenient for studying such interrelations is Lago de Pátzcuaro, México, a shallow lake where carp was first introduced in 1974. The aim of our study was to characterize diet composition, diet breadth and trophic position of C. carpio and local fish fauna, and to assess diet overlap between fish fauna from sites with different habitat characteristics during the wet and the dry seasons. Materials and methods. We assessed the diet of C. carpio and local fish fauna in six sites during the wet and the dry seasons. Stomach content analysis was carried out separately for each length class. The importance of each item was estimated by the index of relative importance (IRI) and the omnivory index was used to assess the feeding behaviour. The trophic guild and trophic position were determined using the TrophLab software and stable isotope analysis. Diet breadth was calculated by Levin’s Index and diet overlap by the Horn’s Index. Fish dorsal muscle and water hyacinth tissues were obtained from nitrogen isotope signature analysis. Results. We found that C. carpio is an omnivorous fish that feeds in shallow areas with water hyacinth cover and rooted macrophytes, consuming mainly detritus and plant debris (>60%). However, δ 15N values indicate that C. carpio is also a secondary consumer because it also ingests invertebrates associated with plant debris. The carp diet overlaps with native blackfin, Goodea atripinnis Jordan, 1880, at most sites. Small carp