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MigraMar

Research methods

Research Methods

Methods

MigraMar relies on several cutting-edge technologies to achieve our scientific and conservation goals:

  • To assess the spatial and temporal behavior of migratory marine species.
  • To assess the spatial and temporal trends in abundance, size structure and biomass productivity of migratory marine species.
  • To assess the behavior and population dynamic response of marine migratory species to changes in the oceanographic setting, particularly in awe of strong environmental events such as ENSO and long-term climate change scenarios.
  • To assess the genetic diversity, gene flow and effective population size between marine species (sub) populations living within the MPAs under assessment.
Research Methods

Spatial and temporal behavior

Satellite Tagging is used to evaluate spatial behavior of fish, turtles, and marine mammals in areas of known aggregation within MPAs as well as national and international waters between them. There are several tag types that are used within the scope of our project: i) tags that are affixed to the fin of a shark (via bolt and nuts or fin clamps), ii) tags that freely float but are affixed via a tether nylon line and an anchoring device (place inside the individual’s muscle over the dorsal area), iii) tags that are affixed to the dorsal area (via suction cups or percutaneous); and iv) tags that are attached into the hard or soft shells in turtles.

Acoustic tagging is use to assess the fine-scale habitat use and connectivity of marine species throughout the ETP region. It consists uses acoustic devices that emit a coded sound signal to passively track a marine animal whenever it passes by receiver stations that are permanently listening for the coded signals. Marine animals are fitted coded VEMCO V16-6H tags (diameter 16mm, length 95mm). These tags can be either tethered to a stainless-steel dart with stainless steel wire and be placed by using a pole spear while free diving, or be surgically implanted in the abdominal cavity of fish.

To passively track all tagged individuals, MigraMar has an array of receivers located all around the Eastern Pacific Ocean. This array is mostly comprised by VEMCO VR2W receivers set at 30 m deep and anchored to concrete blocks by PVC coated marine stainless-steel cable ropes. In some deep-sea areas, VEMCO VRAR underwater acoustic receivers are in place. The detection range of these receiver was previously estimated to vary from a distance of 200 to 300 m. Our array of receivers and the data we are continuously collecting are constantly uploaded to the Ocean Tracking Network portal.

Research Methods

Species response to the environment

To assess the behavior and population dynamic response of marine migratory species to changes in the oceanographic setting, remote sensing data matched with behavioral and population dynamics data is used. Selected oceanographic variables currently used are sea surface temperature (hereafter SST) obtained from the NOAA’s Optimum Interpolated Sea Surface Temperature; Chlorophyll a data from the Moderate Resolution Imaging Spectroradiometer (Modis)-Aqua satellites; and the eddy kinetic energy (hereafter EKE) derived from the TOPEX ⁄ Poseidon and ERS-2 altimeters. The EKE is a measure of the energy associated with the turbulent flow of the ocean.

Research Methods

Genetic diversity, gene flow and effective population

To assess the genetic diversity, gene flow and effective population size between marine species (sub) populations living within the MPAs under assessment, DNA tissue collection will be carried out. This activity was developed with the aim of building on the pre-existing fish, reptiles and marine mammals genetic sample collections that already exists in the region. A Hawaiian sling spear, pneumatic launcher, and crossbows with a modified biopsy tip that is designed to extract the smallest possible amount of tissue from the skin of the fish or mammal will be used. The samples will be labelled and preserved in alcohol.

Research Methods

Animal Ethics: taking care of nature

All the research carried out by MigraMar strictly follows the United States and Australian codes on human and animal experimentation. Our research methods have been carefully reviewed and approved by the Animal Care and Use Committee of the University of California – Davis and the Smithsonian Tropical Research Institute in Panama; the Safety, Ethics and Institutional Biosafety Committees of the University of Tasmania; the Galapagos National Park Directorate animal welfare regulations; the Ministry of Environment and Sustainable Development through the Natural National Parks of Colombia; the Ministry of Environment of Panamá; and the Ministry of Environment of Costa Rica.