Juan Carlos Pérez Jiménez
Who I am
A fisheries research scientist at the College of the Southern Border (EcoSur) in Campeche, Mexico, I am also a biologist at the University of Guadalajara and hold a Master’s and a PhD from the Center for Scientific Research and Higher Education of Ensenada (CICESE), Mexico. During my 20-year career I have written 55 scientific papers and book chapters on several aspects of elasmobranch biology and ecology, as well as elasmobranch-related fisheries. I have been with the IUCN Shark Specialist Group since 2004 and am a member of the workshops advisory panel for the National Marine Fisheries Service’s Atlantic Highly Migratory Species SouthEast Data, Assessment, and Review (SEDAR), which is coordinated by the National Oceanic and Atmospheric Administration (NOAA). As part of a group conducting a regional assessment of the status of shark fisheries, I have been involved in a tripartite initiative between Cuba, Mexico and the USA that examined the marine sciences and conservation in the Gulf of Mexico and the Westen Caribbean. In addition, as a scientific adviser to CONABIO, the Mexican Commission for the Knowledge and Use of Biodiversity, I evaluate shark species listed on CITES Appendices. I recently joined the Blue World Foundation as a scientific adviser and in 2023 participated in fishery-independent surveys in the Guatemalan Caribbean where I focused on deep-water shark species.
Where I work
I conduct research in the southern Gulf of Mexico, where coastal small-scale fisheries catch bony fish and elasmobranch species. More specifically, I work in the western Yucatán Peninsula, in the Mexican states of Campeche and Tabasco. A wide continental shelf, the Campeche Bank, extends as far as 216 kilometres (134 miles) offshore of Campeche, becoming narrower as it follows the coast westward to adjoining Tabasco. The Champotón River, on the central coast of Campeche, divides the western Yucatán Peninsula into two distinct regions: one without rivers and reef areas in the north and, in the south-west, one with rivers and oil platforms. The presence of rivers means that sediments along the shelf change from being calcareous to being terrigenous (derived from erosion on land). This occurs at Terminos Lagoon, the second largest lagoon in the Gulf of Mexico. My study area is therefore divided into a calcareous section and a terrigenous one.
What I do
Typically I visit the fishing ports where small-scale fisheries land their catches and I record data on the fishing effort, such as the days the fishers go out, the gear they use and where they fish. In addition, I note the number of individual sharks or rays caught per species and, from a percentage of the catch, their size, sex and stage of maturity. Sometimes I also include information about an individual’s reproductive organs to estimate its reproductive status. During field work, when landing conditions permit, I collect vertebrae for age and growth studies, and stomachs to analyse feeding habits. With all these data, I estimate catch rates by species and life-history parameters such as size and age at maturity, size at birth, growth rate and reproductive cycle. This helps us understand the effects of fishing on elasmobranch populations.