MESOFISH

About the Project

The MESOFISH project is a multidisciplinary research initiative funded by Fundación CajaCanarias and Fundación Bancaria “La Caixa”, with collaboration from the University of Las Palmas de Gran Canaria (ULPGC) and the Instituto Español de Oceanografía (IEO-CSIC). This three-year study conducts monthly sampling for one year at two key locations, east and south of Gran Canaria, along the continental slope. The project evaluates the functional ecology, trophic dynamics, and environmental vulnerability of mesopelagic fish communities, with funding supporting field campaigns, laboratory analyses, and open dissemination of scientific data.

The mesopelagic ecosystem (the zone extending between 200 and 1000 meters in depth) contains one of the largest concentrations of animal biomass on the planet, mostly composed of fish. These so-called “lantern” or mesopelagic fishes are considered the most abundant vertebrates in the biosphere, playing a fundamental role in marine food webs and in vertical transport processes of organic matter, facilitating carbon sequestration in the ocean depths. Thanks to their daily vertical migrations, they act as key intermediaries in the flow of energy and nutrients between ocean layers, while also accumulating contaminants such as microplastics and heavy metals, whose ecological and human health effects remain poorly understood. Their role in the ecosystem is as relevant as it is enigmatic, since despite their importance, mesopelagic fishes remain one of the least-known groups in the ocean.

Various studies have estimated that their global biomass could exceed 1,000 million tons, which has sparked growing international interest in their commercial exploitation as an alternative source of marine protein, fishmeal, oils for aquaculture, or dietary supplements. This emerging pressure highlights the urgent need for comprehensive scientific understanding of their ecological functions, vulnerability to fishing, and regenerative potential. In this context, the MESOFISH project was launched, proposing a multidisciplinary, long-term evaluation of the functional ecology of mesopelagic fishes in the northeastern Atlantic, with a particular focus on the Canary Islands.

Unlike previous studies, which were spatially or temporally limited, MESOFISH adopts a continuous and seasonal approach through monthly sampling campaigns over an entire year. This design will allow, for the first time in this region, capturing the seasonal variability of key ecological and physiological processes in response to factors such as temperature, primary productivity, and ocean current dynamics. One of the pillars of the project is understanding how climate change and anthropogenic pollution—two of the greatest environmental challenges of our era—affect these organisms, which are considered vectors of the biological carbon pump, as they are capable of transporting carbon to the deep ocean through their daily migrations and metabolic processes. Therefore, studying their physiology, ecology, and resilience has direct implications for climate change mitigation and the sustainability of deep-sea ecosystems.

The main objectives of MESOFISH are:
1. Characterize the functional ecology of representative species through integrated analysis of stomach contents, stable isotopes (δ¹³C and δ¹⁵N), fatty acids, and life cycle parameters (growth, longevity, reproduction, and metabolism). This characterization will allow understanding of their trophic position, ecological plasticity, and physiological adaptations throughout the year.
2. Assess the bioaccumulation of emerging contaminants, particularly microplastics, through gastrointestinal content analysis. Since mesopelagic fishes are an essential part of the marine food web, their exposure to these contaminants could have wide-ranging consequences for ecosystem health and commercially important predator species.
3. Estimate energy demand and metabolic activity of the species through measurements of the electron transport system (ETS), which will allow estimate of respiration rates and their effective contribution to the carbon flux toward the deep ocean.

Additionally, MESOFISH incorporates a crucial axis centered on life cycle studies, essential for understanding the vulnerability of these species to climate change and emerging overfishing. Knowledge of growth rates, reproductive strategies, or longevity is fundamental for modeling population dynamics and predicting their capacity to respond to environmental stress scenarios. This information is indispensable as a scientific basis for future conservation policies or for a potential responsible fishery exploitation, in line with sustainability principles.

The project builds on a solid knowledge base generated by previous initiatives such as the national projects MAFIA, BATHYPELAGIC, or DESAFIO, and in collaboration with European programs like MEESO, SUMMER, or TRIATLAS, with which it shares scientific synergies. However, MESOFISH differs by incorporating a systematic seasonal dimension, absent in most previous studies. This temporal perspective is essential for capturing the real dynamics of biological, chemical, and ecological processes in these deep ecosystems.

The Canary Archipelago offers optimal conditions for the development of this study, not only due to its strategic position in a transition zone between subtropical and temperate waters, but also because of its abrupt oceanic topography, high biodiversity, and strong tradition in research and fishing activity. In particular, the marine shelf of Gran Canaria provides an ideal setting for systematic sampling with adequate logistical access and oceanographic stability throughout the year.

Through the integration of tools from trophic ecology, physiology, biogeochemistry, and ecotoxicology, MESOFISH proposes a holistic and innovative approach to advancing knowledge of mesopelagic ecosystems. Its results will not only improve understanding of the role these fishes play in maintaining global ocean balance, but also assess their vulnerability to global threats such as ocean warming, acidification, pollution, and human exploitation.

In summary, MESOFISH represents a pioneering contribution to the study of one of the most important, yet least-known, components of the Earth’s climate system. The data obtained will serve as a key reference for designing adaptation and conservation strategies in the context of a Climate Emergency, and for evaluating, with solid scientific criteria, the true potential and risks associated with incorporating mesopelagic biomass into future blue economy models.

Our Mission

The work plan is structured into the following six work packages (WPs), each comprising specific tasks, responsible personnel, and expected milestones:

WP1: SAMPLE COLLECTION AND INITIAL PROCESSING

Objective: Obtain a representative set of mesopelagic fish throughout an entire annual cycle.

• Task 1.1: Identification and location of schools using video cameras (MOPS).
  Responsible: Dr. Antonio Carlos Domínguez Brito
  Milestone: Validation of the MOPS system for accurate school detection.
• Task 1.2: Monthly sample collection via oceanographic cruises.
  Responsible: Dr. Santiago Hernández León, Dr. Airam N. Sarmiento Lezcano, MESOFISH hire, ULPGC researchers
  Milestone: Completion of 12 cruises with recorded and preserved samples.
• Task 1.3: Taxonomic identification and biometrics of each individual, and preservation for further analyses.
  Responsible: Dr. Airam N. Sarmiento Lezcano, MESOFISH hire
  Milestone: Database with biological metadata and classified samples.

WP2: TROPHIC ANALYSIS

Objective: Determine diet, trophic level, and carbon/nitrogen sources of the species.

• Task 2.1: Stomach content analysis.
  Responsible: Dr. Airam N. Sarmiento Lezcano
  Milestone: Table of prey frequencies by species and size.
• Task 2.2: Analysis of stable isotopes (δ¹³C and δ¹⁵N) and fatty acids.
  Responsible: Dr. Airam N. Sarmiento Lezcano
  Milestone: Estimation of trophic position and niche.

WP3: LIFE HISTORY TRAITS

Objective: Describe growth and reproduction.

• Task 3.1: Otolith reading to estimate growth rates.
  Responsible: Dr. Airam N. Sarmiento Lezcano and MESOFISH hire
  Milestone: Growth rates and length-age curves by species.
• Task 3.2: Reproduction assessment: determination of gonadal maturity, GSI, fecundity.
  Responsible: Dr. María José Caballero Cansino
  Milestone: Reproductive parameters by species.

WP4: CONTAMINATION

Objective: Assess the presence of contaminants.

• Task 4.1: Quantification of microplastics in stomachs.
  Responsible: Dr. Airam N. Sarmiento Lezcano
  Milestone: Concentrations by species and tissue.

WP5: METABOLISM STUDY

Objective: Evaluate the metabolic activity of species through ETS assays.

• Task 5.1: Analysis of electron transport system (ETS) activity in muscle tissues.
  Responsible: Dr. Santiago Hernández León and MESOFISH hire
  Milestone: Standardized respiration rate by biomass and temperature.

WP6: RESULTS INTEGRATION AND DISSEMINATION

Objective: Synthesize generated information and disseminate results.

• Task 6.1: Integrated statistical analysis of all collected data.
  Responsible: Dr. Santiago Hernández León and Dr. Airam N. Sarmiento Lezcano
  Milestone: Results prepared for publication.
• Task 6.2: Writing scientific articles, presenting at conferences, disseminating results through social media (Instagram, Facebook, LinkedIn), and writing thesis/final report.
  Responsible: Dr. Santiago Hernández León, Dr. Airam N. Sarmiento Lezcano, Dr. María José Caballero Cansino, Dr. Antonio Domínguez Brito, and MESOFISH hire
  Milestone: Submission of at least 4 manuscripts and participation in at least 1 conference.

Project Team

Dr. Airam N. Sarmiento Lezcano

Project Coordinator/Researcher

Affiliation: Instituto Español de Oceanografía (IEO-CSIC), Spain

Email: airam.sarmiento@ieo.csic.es

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Dr. Airam N. Sarmiento Lezcano

Description: Postdoctoral researcher at the Spanish Institute of Oceanography (IEO-CSIC). His research focuses on the ecology, trophic dynamics, and population structure of mesopelagic fishes, with particular interest in their role in oceanic food webs and biogeochemical cycles.

Role: Overall coordination of the MESOFISH project, leading field campaigns, supervising data collection and analysis, integrating results, and preparing reports.

Website: airam.EPB.es

Social Media:

Dr. Santiago Hernández León

Principal Investigator

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: shernandezleon@ulpgc.es

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Dr. Santiago Hernández León

Description: Professor of Marine Ecology at the University of Las Palmas de Gran Canaria (ULPGC). Senior researcher at the Institute of Oceanography and Global Change (IOCAG). His research focuses on zooplankton ecology, oceanic food webs, and biogeochemical cycles, with particular emphasis on the role of mesopelagic organisms in carbon flux and ecosystem functioning in the open ocean.

Role: Design of trophic ecology studies, supervising laboratory analyses, mentoring junior researchers, and interpreting data for ecological models.

Website: santiago.ulpgc.es

Social Media:

Dr. María José Caballero Cansino

Co-director

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: mariajose.caballero@ulpgc.es

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Dr. María José Caballero Cansino

Description: Professor of Veterinary Medicine in the Department of Morphology at the University of Las Palmas de Gran Canaria (ULPGC). Senior Researcher at the Institute of Animal Health and Food Safety (IUSA) and European Specialist in Aquatic Animal Health (ECAAH). Her research focuses on fish anatomy, histology, physiology and pathology.

Role: Coordination of lab work, development of methodological protocols, supervision of analytical workflows, and quality control of data.

Website: maria.ulpgc.es

Social Media:@peces.iusa | @iusa.ulpgc

Dr. Antonio Domínguez Brito

Researcher

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: antonio.dominguez@ulpgc.es

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Dr. Antonio Domínguez Brito

Description: Associate Professor in the Department of Computer Science and Systems at the University of Las Palmas de Gran Canaria (ULPGC). His work focuses on computational methods, data analysis, and information systems applied to scientific research, supporting the processing, visualization, and interpretation of complex datasets.

Role: Data analysis, field sampling, contributing to ecological modelling, preparation of figures, and integration of lab and field results.

Website: antonio.ulpgc.es

Social Media:

Work Team

Dr. Laia Armengol

Work Team

Affiliation: Instituto Español de Oceanografía (IEO-CSIC), Spain

Email: laia.armengol@ieo.csic.es

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Dr. Laia Armengol

Description:PhD in Oceanography and Global Change. Scientific and Technical Consultant in Oceanography at the Instituto Español de Oceanografía (IEO-CSIC). Her research focuses on the ecology marine plankton, with particular emphasis on mixotrophic microorganisms and their role in marine food webs and biogeochemical cycles.

Role: Coordination of phytoplankton sampling and analyses, development of methodological protocols, supervision of laboratory workflows, and quality control of phytoplankton data

Website: -

Social Media:

Dr. Cristina López Pérez

Work Team

Affiliation: Instituto de Ciencias del Mar (ICM-CSIC), Spain

Email: clopez@icm.csic.es

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Dr. Cristina López Pérez

Description: Researcher at the Spanish Institute of Oceanography (IEO-CSIC). Her research focuses on marine ecology and fisheries science, with particular interest in the biology, population dynamics, and trophic ecology of pelagic and mesopelagic fishes, contributing to a better understanding of their role in oceanic ecosystems.

Role: Coordination of fish reproductive data analysis and interpretation, development of methodological protocols, supervision of analytical workflows, and quality control of reproductive datasets

Website: -

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MSc. Giorgio Leonardi

Work Team

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: giorgioleonardi66@gmail.com

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MSc. Giorgio Leonardi

Description:PhD student at ULPGC

Role: Technical support for field cruises and laboratory activities, maintenance of sampling equipment, data organization, and assistance in analytical workflows.

Website: -

Social Media:

MSc. Lorena Martínez Leiva

Work Team

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: lorena.martinez102@alu.ulpgc.es

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MSc. Lorena Martínez Leiva

Description:PhD student at ULPGC

Role: Technical support for field cruises and laboratory activities, maintenance of sampling equipment, data organization, and assistance in analytical workflows.

Website: -

Social Media:

MSc. Nicolás Larrumbide Zúñiga

Work Team

Affiliation: University of A Coruña, Spain

Email: n.larrumbide@gmail.com

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MSc. Nicolás LarrumbideZúñigaa

Description:PhD student at UAC

Role: Technical support for field cruises and laboratory activities, maintenance of sampling equipment, data organization, and assistance in analytical workflows.

Website: -

Social Media:

MSc. Javier Díaz Pérez

Work Team

Affiliation: University of Las Palmas de Gran Canaria, Spain

Email: javier.perez@ulpgc.es

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MSc. Javier Díaz Pérez

Description: PhD student at ULPGC

Role: Coordination of decapods sampling and analyses, development of methodological protocols, supervision of laboratory workflows, and quality control of decapods data

Website: -

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In Situ Data

These figures display environmental variables extracted from the Copernicus Marine Environment Monitoring Service. They provide an overview of the oceanographic conditions in the study area, including sea surface temperature, currents, chlorophyll concentration, sea surface height, and estimated mesopelagic biomass. Together, these datasets help contextualize the physical and biological processes influencing mesopelagic fish ecology.

Physical Oceanography

Sea Surface Temperature and surface currents ℹ️ Sea surface temperature and surface circulation patterns that influence stratification, productivity, and horizontal transport of zooplankton and micronekton.

Sea Surface Temperature and geostrophic currents ℹ️ Sea surface temperature combined with geostrophic circulation derived from satellite altimetry, highlighting mesoscale ocean dynamics.

Sea Surface Height and geostrophic circulation ℹ️ Sea surface height anomalies and derived geostrophic flow revealing mesoscale structures such as eddies and fronts affecting ecosystem variability.

Primary Productivity

Chlorophyll concentration and geostrophic currents ℹ️ Chlorophyll-a concentration as a proxy for phytoplankton biomass, indicating primary productivity and potential feeding grounds.

Water Column Structure

Vertical profiles at sampling locations ℹ️ Vertical profiles of physical and biogeochemical variables describing water column structure and habitat conditions for pelagic organisms. Two points are shown, one east of the island and another south of it, representing potential sampling locations.

Mesopelagic Ecosystem

Estimated daily biomass of mesopelagic fishes ℹ️ Estimated mesopelagic fish biomass derived from acoustic or modeled micronekton distributions, showing temporal variability in deep pelagic communities.

Temporal series of zooplankton, micronekton, and NPP ℹ️ Time series of biogeochemical and micronekton variables used to examine environmental variability and potential drivers of mesopelagic ecosystem dynamics.

What’s New