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Javier Tovar-Ávila

Javier Tovar-Ávila
Instituto Nacional de Pesca y Acuacultura Mexico

Doctor of Philosophy

About

36
Publications
13,468
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302
Citations

Publications

Publications (36)
Chapter
Full-text available
En este trabajo se evalúa por primera vez los riesgos de vulnerabilidad para cada especie (A. pelagicus, A. vulpinus, A. superciliosus, C. falciformis, I. oxyrinchus e I. paucus) bajo los estresores asociados al cambio climático. Aunque este método de evaluación requiere información de campo, el método es rentable porque la mayoría de la informació...
Article
Shrimp trawl fisheries capture several species of elasmobranchs as bycatch that are commonly unreported, this lack of data makes it difficult to assess their populations using quantitative stock assessment methods. Rapid evaluations like the productivity and susceptibility analysis (PSA), can help to determine species at risk of overexploitation an...
Article
The median disc width at maturity DW^50) of males (n=91, 32.2–92.0 cm) and females (n=157, 31.0–130.0 cm) of the bat ray (Myliobatis californica) was estimated through a multi-model inference in northwestern Mexico. Gompertz’s model and four common logistics models (Lysack, Bakhayokho, White, and Brouwer and Griffiths) were compared and all fit the...
Article
We report results from the first detailed investigation of elasmobranch bycatch that contains data on species, sex, and length-frequency distributions of animals collected in the coastal south-eastern and entrance region of the Gulf of California. Using data from fishery-independent prawn trawl surveys between 2011–17, we found differences between...
Article
International trade in vulnerable marine species is regulated once they are listed in CITES Appendices (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Parties to the Convention submit proposal(s) 150 days prior to the CITES Conference for voting on the inclusion of new species in Appendices I and II, making a...
Article
The age of 296 juvenile scalloped hammerhead sharks Sphyrna lewini caught by several fisheries in the Mexican Pacific Ocean from March 2007 to September 2017 were estimated from growth‐band counts in thin‐sectioned vertebrae. Marginal‐increment analysis (MIA) and centrum‐edge analysis (CEA) were used to verify the periodicity of formation of the gr...
Chapter
Mexico is home to a broad biodiversity of shark species, and more than half of the sharks in Mexican waters are distributed in the Mexican Pacific, with over 62 species recorded. This high biodiversity is the result of numerous and diverse marine and coastal environments, including the dynamic Mexican seas, where circulation and spatial variation o...
Chapter
Feeding studies, since traditional stomach content analysis to stable isotopes analyses, provides insights into the trophic relationship among the apex predators and the ecosystems they inhabit. The Pacific Coast of Mexico (PCM) is inhabited by 62 known species (or 12%) of living sharks, which belong to 21 families and 34 genera. We divide the Paci...
Article
Full-text available
The brown smooth-hound shark Mustelus henlei is one of the most abundant species caught by the artisanal elasmobranch fishery off northwestern Mexico. The present study estimates the reproductive parameters for M. henlei using, for the first time, histological analysis and survey data collected from May 2008 to May 2016. Mustelus henlei was reporte...
Article
Quantitative assessments of shark populations are difficult to undertake due to the scarcity of studies focusing on species identification and landings. We used the productivity and susceptibility analysis and a rapid management-risk assessment (M-risk) method to examine the impact of the artisanal fishery on 29 shark species captured and landed of...
Technical Report
Full-text available
This aim of this working paper is to contribute to the knowledge of the spatially and temporal length and sex structure of the blue shark in the North Pacific Ocean with recent information from the Mexican longlines fleets which operate in the west coast of the Mexican Pacific. Data on 71,803 blue sharks measured on board by observers from two prin...
Article
Defining species boundaries is important not only for the appropriate attribution of life history and ecological traits but also for sustainable fishery management and for the conservation of biodiversity. Problems arise from taxonomic uncertainty and incorrect species delineation leading to historical misidentification. This is the case of Pacific...
Article
Full-text available
The silky shark Carcharhinus falciformis is one of the most important species in the shark catches in Mexico and maintains several fisheries along the Central Mexican Pacific. Based on information from catch and fishing effort collected by scientific observers on board semi-industrial fishery vessels of Manzanillo, Colima, the temporal variation of...
Article
The silky shark Carcharhinus falciformis is one of the most important species in the shark catches in Mexico and maintains several fisheries along the Central Mexican Pacific. Based on information from catch and fishing effort collected by scientific observers on board semi-industrial fishery vessels of Manzanillo, Colima, the temporal variation of...
Chapter
Full-text available
En el primer capítulo se realiza una evaluación rápida (análisis de productividad y susceptibilidad, aps) del riesgo relativo de todas las especies incluidas en el Apéndice ii de la cites a los efectos de las flotas pesqueras tiburoneras mexicanas, con el fin de detectar necesidades de investigación y prioridades de protección y manejo. En este aná...
Chapter
Full-text available
El tercer capítulo se describen las características sociodemográficas e indicadores económicos de los pescadores de tiburón del litoral del Pacífico, un tema pocas veces abordado pero esencial para el desarrollo y la mejora de las medidas de manejo necesarias para su protección y aprovechamiento sustentable.
Article
Full-text available
Given their biological characteristics, sharks exhibit low resilience and thereby are considered a fishery resource particularly vulnerable to overfishing. Yet, for several decades, three shark species (Sphyrna lewini, Rhizoprionodon longurio, and Carcharhinus falciformis) have contributed consistently to the catches of the artisanal shark fishery...
Article
Full-text available
In Mexico sharks are an important fishery resource, however, their biological characteristics make them highly vulnerable to overfishing. In order to assess the vulnerability (v) and ecological risk (ER) of 20 species caught by the artisanal fishery at the entrance of the Gulf of California, a Productivity and Susceptibility Analysis (PSA) was perf...
Article
Shark landings are not registered by species in Mexico, preventing their use for population assessments and fishery management. In the present study temporal variations of landings in the islands and central region of Nayarit are determined based in the official records, analyzing their usefulness and deficiencies. Total monthly catches were estima...
Article
The estimated age (around 45 years) from vertebral growth band counts for the largest Sphyrna mokarran caught in the Gulf of California and Central Mexican Pacific in the last decades, locates it as the oldest elasmobranch reported to date in Mexican Pacific waters. The specimen studied was a mature female of approximately 550 kg of total weight an...
Article
Full-text available
The suitability of using the interdorsal length (IL) to estimate total (TL), fork (FL) and precaudal (PL) lengths of Carcharhinus falciformis in the Central Mexican Pacific (CMP) was analyzed. A linear model described adequately the relationships (TL = 3.974IL + 8.277, FL = 3.297IL + 6.561 and PL = 3.016IL + 4.814, r = 0.99 and p < 0.001 in all cas...
Article
The estimated age (around 45 years) from vertebral growth band counts for the largest Sphyrna mokarran caught in the Gulf of California and Central Mexican Pacific in the last decades, locates it as the oldest elasmobranch reported to date in Mexican Pacific waters. The specimen studied was a mature female of approximately 550 kg of total weight an...
Article
Shark landings are not registered by species in Mexico, preventing their use for population assessments and fishery management. In the present study temporal variations of landings in the islands and central region of Nayarit are determined based in the official records, analyzing their usefulness and deficiencies. Total monthly catches were estima...
Article
Full-text available
Evaluación de riesgo ecológico de la pesca artesanal para los tiburones capturados en la entrada del Golfo de California Ecological risk assessment of artisanal capture methods on sharks fished at the entrance of the Gulf of California Golfo de California. (2014) Hidrobiológica 24 (2): 83-97. RESUMEN En México los tiburones son un importante recurs...
Article
A rapid semi-quantitative ecological risk assessment method (productivity and susceptibility analysis) indicated that, despite its low biological productivity, the Port Jackson shark Heterodontus portusjacksoni is at low risk to all fishing methods in far-eastern Victoria, Australia, under the present fishing practices, because of its low catch sus...
Article
Full-text available
Three stochastic models were used to describe the growth of Heterodontus portusjacksoni off eastern Victoria, Australia. The models are based on a reparametrization of the von Bertalanffy growth model to take account of length-at-age heterogeneity, and incorporate random variation of the von Bertalanffy growth coefficient (k), using three different...
Article
Full-text available
Four methods for counting growth bands using vertebrae and dorsal-fin spines of the Port Jackson shark, Heterodontus portusjacksoni, are compared. Both calcified structures presented observable growth bands, allowing cross comparison among structures for the first time in a shark species. Whole and sectioned vertebrae and dorsal fin-spines possess...
Article
Four methods for counting growth bands using vertebrae and dorsal-fin spines of the Port Jackson shark, Heterodontus portusjacksoni, are compared. Both calcified structures presented observable growth bands, allowing cross comparison among structures for the first time in a shark species. Whole and sectioned vertebrae and dorsal fin-spines possess...
Technical Report
Full-text available
The present report provides a comprehensive collation of results relevant to rapid assessment of sustainability for ecological risk of sharks, rays and holocephalans in southern Australia. The present study complements a similar study titled ‘Northern Australian sharks and rays: the sustainability of target and bycatch species, Phase 2’ (FRDC 2002/...
Article
Full-text available
A prospective model of dorsal-fin spine growth in chondrichthyans is devised by studying the growth of spines from captive and wild Heterodontus portusjacksoni injected with several fluorochromes. Evidence was found for only two dentine layers in the spine trunk of H. portusjacksoni, contrasting with conjectures about the presence of a third middle...
Article
Full-text available
Age and growth estimates of Squalus megalops were derived from the first dorsal fin spine of 452 sharks, ranging from 274 to 622 mm total length. Age bias plots and indices of precision indicated that the ageing method was precise and unbiased. Edge analysis of the enameled surface of whole spines and similarities in the banding pattern deposited i...
Article
Full-text available
Significant differences in the length–frequency composition of catch samples, mass–length relationships and length-at-maturity found between Heterodontus portusjacksoni from western and far-eastern Victoria, suggest the presence of at least two separate breeding populations off south-eastern Australia, with some mixing between these regions. In eac...

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Projects

Projects (6)
Project
1. TO EVALUATE THE VULNERABILITY OF FISHERIES POPULATIONS, PARTICULARLY CHONDRICHTHYANS TO FISHING AND CLIMATE CHANGE STRESSORS. 2. TO IDENTIFY THOSE SPECIES AT HIGH VULNERABILITY AND RISK.