Publications by authors named "Lorenzo Rojas-Bracho"

To understand the scope and scale of the loss of biodiversity, tools are required that can be applied in a standardized manner to all species globally, spanning realms from land to the open ocean. We used data from the International Union for the Conservation of Nature Red List to provide a synthesis of the conservation status and extinction risk of cetaceans. One in 4 cetacean species (26% of 92 species) was threatened with extinction (i.

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Widespread use of unregulated acoustic technologies in maritime industries raises concerns about effects on acoustically sensitive marine fauna worldwide. Anthropogenic noise can disrupt behavior and may cause short- to long-term disturbance with possible population-level consequences, particularly for animals with a limited geographic range. Ultrasonic antifouling devices are commercially available, installed globally on a variety of vessel types, and are marketed as an environmentally-friendly method for biofouling control.

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In cases of severe wildlife population decline, a key question is whether recovery efforts will be impeded by genetic factors, such as inbreeding depression. Decades of excess mortality from gillnet fishing have driven Mexico's vaquita porpoise () to ~10 remaining individuals. We analyzed whole-genome sequences from 20 vaquitas and integrated genomic and demographic information into stochastic, individual-based simulations to quantify the species' recovery potential.

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The vaquita is the most critically endangered marine mammal, with fewer than 19 remaining in the wild. First described in 1958, the vaquita has been in rapid decline for more than 20 years resulting from inadvertent deaths due to the increasing use of large-mesh gillnets. To understand the evolutionary and demographic history of the vaquita, we used combined long-read sequencing and long-range scaffolding methods with long- and short-read RNA sequencing to generate a near error-free annotated reference genome assembly from cell lines derived from a female individual.

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Historical variation in food resources is expected to be a major driver of cetacean evolution, especially for the smallest species like porpoises. Despite major conservation issues among porpoise species (e.g.

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Article Synopsis
  • * Researchers examined nine vaquita carcasses between 2016 and 2018 to investigate their cause of death, finding evidence of fisheries bycatch but low levels of harmful pollutants.
  • * The study concludes that gillnet bycatch is the main reason for the vaquita's declining population, highlighting an urgent need for stronger protective measures in their habitat.
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Article Synopsis
  • The vaquita is a critically endangered porpoise found only in Mexico, facing severe population decline primarily due to bycatch in gillnets.
  • Despite a gillnet ban implemented in 2015, the population has continued to plummet, with estimates showing a 98.6% decline since 2011, leaving fewer than 19 individuals by the summer of 2018.
  • Ongoing illegal gillnet use remains a significant threat, necessitating urgent management initiatives to prevent the species from going extinct.
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The vaquita is a critically endangered species of porpoise. It produces echolocation clicks, making it a good candidate for passive acoustic monitoring. A systematic grid of sensors has been deployed for 3 months annually since 2011; results from 2016 are reported here.

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Article Synopsis
  • - The vaquita is the most endangered marine mammal, with around 245 individuals left in 2008, primarily due to bycatch in gillnets used for illegal fishing of the totoaba fish, which is highly valued in the wildlife trade.
  • - Population monitoring is challenging because vaquitas are hard to see; however, acoustic detectors revealed an 80% decline in their echolocation activity from 2011 to 2015, indicating a drastic decrease in their population.
  • - In response to these alarming findings, the Mexican government implemented a two-year gillnet ban in the vaquita's habitat to prevent extinction, costing about $74 million to compensate affected fishers, highlighting the importance of ongoing monitoring for
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The main objective of this study was to apply a set of sensitive non-lethal biomarkers in skin biopsies of fin whales (Balaenoptera physalus) to evaluate the toxicological status of this mysticete in the Pelagos Sanctuary (Mediterranean Sea) and in the Gulf of California (Sea of Cortez-Mexico). We developed a "multi-trial diagnostic tool" (based on field and in vitro studies), combining molecular biomarkers (western blot of CYP1A1, CYP2B) and gene expression (qRT-PCR of HSP70, ERα, AHR, E2F-1) with the analysis of OCs, PAHs and PBDEs. The study revealed a higher level of toxicological stress in the Mediterranean fin whales.

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Accurate knowledge of population structure in cetaceans is critical for preserving and managing breeding habitat, particularly when habitat is not uniformly protected. Most eastern gray whales return to their major breeding range each winter along the Pacific coast of Baja California, Mexico, concentrating in 3 major calving lagoons, but it is unknown whether genetic differences exist between lagoons. Previous photo-identification studies and genetic studies suggest that gray whales may return to their natal lagoons to breed, potentially resulting in the buildup of genetic differences.

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Although many studies confirm long-term small isolated populations (e.g. island endemics) commonly sustain low neutral genetic variation as a result of genetic drift, it is less clear how selection on adaptive or detrimental genes interplay with random forces.

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