54 research outputs found
Eficacia de la persecución penal en la investigación preparatoria del delito de fraude informático, Callao, 2022
El estudio tuvo el propósito de analizar cómo la eficacia de la persecución penal
influye en la investigación preparatoria del delito de fraude informático, Callao,
2022. Se aplicó el enfoque cualitativo, tipo básico, con un diseño fenomenológico,
aplicándose la guía de entrevista como instrumentos de recolección de datos, seis
fiscales, dos asistentes en función fiscal y dos abogados litigantes, conforme a ello
a ello se llegó a la conclusión que existe una investigación penal ineficaz durante la
etapa de investigación preparatoria del delito de fraude informático, ello en razón a
que no se han creado fiscalías especializadas en Ciberdelincuencia en el distrito
fiscal del Callao, generando con ello deficientes investigaciones llevadas a cabo por
Fiscalías Corporativas
Characterizing larval swordfish habitat in the western tropical North Atlantic
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Fisheries Oceanography, 27 (2018): 246-258, doi:10.1111/fog.12249.Swordfish Xiphias gladius (Linnaeus, 1758) are a circumglobal pelagic fish targeted by
multiple lucrative fisheries. Determining the distribution of swordfish larvae is important for
indicating reproductive activity and understanding the early life history of swordfish. We
identify and characterize larval swordfish distributions during peak swordfish spawning
throughout the Gulf of Mexico and western Caribbean Sea with generalized additive models
(GAMs) using catches of swordfish larvae during ichthyoplankton surveys in April and May of
2010, 2011, and 2012. The best fit GAM, as determined by stepwise, backward Akaike
Information Criterion selection, included both physiochemical (temperature at 5 m, sea surface
height anomaly (SSHA), eddy kinetic energy (EKE)), temporal (lunar illumination, hour of
sampling) and spatial (location) variables, while near-surface chlorophyll a concentration
residuals remained as a random effect. The highest probability of larval swordfish catch occurred
at sub-surface temperatures, SSHA, and EKE values indicative of boundary currents. Standard
lengths of larvae were larger further downstream in the boundary currents, despite high
variability in length with location due to multiple spawning locations of swordfish near these
currents. Probability of larval swordfish catch also peaked during the crescent and gibbous
moons, indicating a lunar periodicity to swordfish spawning. These results suggest that swordfish may spawn during select moon phases near boundary currents that transport their larvae to larval
and juvenile habitat including the northern Gulf of Mexico and coastal waters of the southeast
United States.NASA Grant Numbers: NNX11AP76G, NNX08AL06
Influence of food quality on larval growth of Atlantic bluefin tuna (Thunnus thynnus) in the Gulf of Mexico
Larval abundances of Atlantic bluefin tuna (ABT) in the Gulf of Mexico are currently utilized to inform future recruitment by providing a proxy for the spawning potential of western ABT stock. Inclusion of interannual variations in larval growth is a key advance needed to translate larval abundance to recruitment success. However, little is known about the drivers of growth variations during the first weeks of life. We sampled patches of western ABT larvae in 3–4 day Lagrangian experiments in May 2017 and 2018, and assessed age and growth rates from sagittal otoliths relative to size categories of zooplankton biomass and larval feeding behaviors from stomach contents. Growth rates were similar, on average, between patches (0.37 versus 0.39 mm d−1) but differed significantly through ontogeny and were correlated with a food limitation index, highlighting the importance of prey availability. Otolith increment widths were larger for postflexion stages in 2018, coincident with high feeding on preferred prey (mainly cladocerans) and presumably higher biomass of more favorable prey type. Faster growth reflected in the otolith microstructures may improve survival during the highly vulnerable larval stages of ABT, with direct implications for recruitment processes.En prensa1,74
Bluefin Tuna Larvae in Oligotrophic Ocean Foodwebs, Investigations of Nutrients to Zooplankton: Overview of the BLOOFINZ-Gulf of Mexico program
Western Atlantic bluefin tuna (ABT) undertake long-distance migrations from rich feeding grounds in the North Atlantic to spawn in oligotrophic waters of the Gulf of Mexico (GoM). Stock recruitment is strongly affected by interannual variability in the physical features associated with ABT larvae, but the nutrient sources and food-web structure of preferred habitat, the edges of anticyclonic loop eddies, are unknown. Here, we describe the goals, physical context, design and major findings of an end-to-end process study conducted during peak ABT spawning in May 2017 and 2018. Mesoscale features in the oceanic GoM were surveyed for larvae, and five multi-day Lagrangian experiments measured hydrography and nutrients; plankton biomass and composition from bacteria to zooplankton and fish larvae; phytoplankton nutrient uptake, productivity and taxon-specific growth rates; micro- and mesozooplankton grazing; particle export; and ABT larval feeding and growth rates. We provide a general introduction to the BLOOFINZ-GoM project (Bluefin tuna Larvae in Oligotrophic Ocean Foodwebs, Investigation of Nitrogen to Zooplankton) and highlight the finding, based on backtracking of experimental waters to their positions weeks earlier, that lateral transport from the continental slope region may be more of a key determinant of available habitat utilized by larvae than eddy edges per se.Postprint1,74
Genetic connectivity between Atlantic bluefin tuna larvae spawned in the Gulf of Mexico and in the Mediterranean Sea
The highly migratory Atlantic bluefin tuna (ABFT) is currently managed as two distinct stocks, in accordance with natal homing behavior and population structuring despite the absence of barriers to gene flow. Larval fish are valuable biological material for tuna molecular ecology. However, they have hardly been used to decipher the ABFT population structure, although providing the genetic signal from successful breeders. For the first time, cooperative field collection of tuna larvae during 2014 in the main spawning area for each stock, the Gulf of Mexico (GOM) and the Mediterranean Sea (MED), enabled us to assess the ABFT genetic structure in a precise temporal and spatial frame exclusively through larvae. Partitioning of genetic diversity at nuclear microsatellite loci and in the mitochondrial control region in larvae spawned contemporarily resulted in low significant fixation indices supporting connectivity between spawners in the main reproduction area for each population. No structuring was detected within the GOM after segregating nuclear diversity in larvae spawned in two hydrographically distinct regions, the eastern GOM (eGOM) and the western GOM (wGOM), with the larvae from eGOM being more similar to those collected in the MED than the larvae from wGOM. We performed clustering of genetically characterized ABFT larvae through Bayesian analysis and by Discriminant Analysis of Principal Components (DAPC) supporting the existence of favorable areas for mixing of ABFT spawners from Western and Eastern stocks, leading to gene flow and apparent connectivity between weakly structured populations. Our findings suggest that the eastern GOM is more prone for the mixing of breeders from the two ABFT populations. Conservation of this valuable resource exploited for centuries calls for intensification of tuna ichthyoplankton research and standardization of genetic tools for monitoring population dynamics.This collaborative study was supported by “ECOLATUN” PROJECT CTM2015-68473-R (MINECO/FEDER) funded by Spanish Ministry of Economy and Competitiveness; “TUNAGEN” project funded by Instituto Español de Oceanografía (IEO); and “BLUEFIN” project financed by IEO and Balearic Island Observing and Forecasting System (SOCIB). This research was funded by NASA (NNX11AP76G S07), the NOAA National Marine Fisheries Science Service through the Southeast Fisheries Science Center, as well as by the Cooperative Institute for Marine and Atmospheric Studies under Cooperative Agreement NA15OAR43200064 at the University of Miami, Miami, FL, USA. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.En prens
Do western Atlantic bluefin tuna spawn outside of the Gulf of Mexico? Results from a larval survey in the Atlantic Ocean in 2013
In 2013, a larval survey was conducted north and east of the Bahamas aboard the NOAA Ship
NANCY FOSTER. Sampling areas were selected based on larval habitat model predictions, and
daily satellite analysis of surface temperature and ocean color. Samples were collected at 97
stations, and 18 larval BFT (Thunnus thynnus) were found at 9 stations. Six of these stations came
from oceanographically complex regions characterized by cyclonic and anticyclonic gyres. Larvae
ranged in size from 3.22mm to 7.58 mm, corresponding to approximately 5-12 days in age. Analysis
of satellite derived surface currents and CTD data suggest that these larvae were spawned and
retained in this area. Larval habitat models show areas of high predicted abundance extending east
to 650 W, but the actual extent of spawning in this area remains unknown.En prens
Trade-Offs Between Risks of Predation and Starvation In Larvae Make the Shelf Break an Optimal Spawning Location For Atlantic Bluefin Tuna
Atlantic bluefin tuna (ABT) (Thunnus thynnus) travel long distances to spawn in oligotrophic regions of the Gulf of Mexico (GoM) which suggests these regions offer some unique benefit to offspring survival. To better understand how larval survival varies within the GoM a spatially explicit, Lagrangian, individual-based model was developed that simulates dispersal and mortality of ABT early life stages within realistic predator and prey fields during the spawning periods from 1993 to 2012. The model estimates that starvation is the largest cumulative source of mortality associated with an early critical period. However, elevated predation on older larvae is identified as the main factor limiting survival to late postflexion. As a result, first-feeding larvae have higher survival on the shelf where food is abundant, whereas older larvae have higher survival in the open ocean with fewer predators, making the shelf break an optimal spawning area. The modeling framework developed in this study explicitly simulates both physical and biological factors that impact larval survival and hence could be used to support ecosystem based management efforts for ABT under current and future climate conditions
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45th Annual Larval Fish Conference & 13th International Larval Biology Symposium San Diego, California 29 August – 1 September, 2022
INDITU
Plankton food webs of the Gulf of Mexico spawning grounds of Atlantic Bluefin tuna
We used linear inverse ecosystem modeling techniques to assimilate data from extensive Lagrangian field experiments
into a mass-balance constrained food web for the Gulf of Mexico open-ocean ecosystem. This region is highly
oligotrophic, yet Atlantic bluefin tuna (ABT) travel long distances from feeding grounds in the North Atlantic to
spawn there. Our results show extensive nutrient regeneration fueling primary productivity (mostly by cyanobacteria
and other picophytoplankton) in the upper euphotic zone. The food web is dominated by themicrobial loop (>70% of
net primary productivity is respired by heterotrophic bacteria and protists that feed on them). By contrast, herbivorous
food web pathways from phytoplankton to metazoan zooplankton process <10% of the net primary production
in the mixed layer. Nevertheless, ABT larvae feed preferentially on podonid cladocerans and other suspensionfeeding
zooplankton, which in turn derive much of their nutrition from nano- and micro-phytoplankton (mixotrophic
flagellates, and to a lesser extent, diatoms). This allows ABT larvae to maintain a comparatively low trophic level (∼4.2
for preflexion and postflexion larvae), which increases trophic transfer from phytoplankton to larval fish.ECOLATUNECOlogía trófica comparativa de LArvas de aTUN rojo atlántico (Thunnus thynnus) de las áreas de puesta del Medterraneo-NO y el Golfo de México.S
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