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 relation to strong environmental events such as El Niño Southern Oscillation 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.
Spatial and temporal behavior
Satellite Tagging is used to evaluate spatial behavior of fish, turtles, and marine mammals at aggregation sites within MPAs as well as in the national and international waters between them. We use several types of tag: 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 (placed 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 to the hard or soft shells in turtles.
Acoustic tagging is used to assess the fine-scale habitat use and connectivity of marine species throughout the Eastern Pacific. It uses acoustic devices that emit a coded signal which can be detected by receiver stations deployed at key sites whenever the animal comes within range (usually around 200 m). These tags can either be tethered to a stainless-steel dart with stainless steel wire and attached by using a pole spear, or be surgically implanted in the abdominal cavity of fish. MigraMar has an array of receivers located at island and coastal locations throughout the Eastern Pacific Ocean. Our array of receivers and the data we collect are constantly uploaded to the Ocean Tracking Network portal Ocean Tracking Network portal.
Spatial and temporal abundance trends
The baited remote underwater video stations (BRUVs) (BRUVS) technique is used to assess abundance, size structure and biomass of pelagic marine species. A stereo-BRUVS consists of two front facing cameras placed at an angle of 8 degrees which are used to create a three-dimensional (stereo) image, which is later used to measure any object (or fish) that passes in front of the cameras. A BRUVS set has three to five 3D stations placed in parallel resembling longline fishing gear. While BRUVS use bait to attract fish with the smell, it replaces hooks from longlines for the 3D camera systems. This makes it a non-invasive technique in comparison to experimental fishing. Also, our BRUVS systems are coupled with a central 360 camera to allow observing animals passing by all angles and reduce bias associated to counting individuals while watching a reduced field of view.
BRUVS deployment is generally done near seamounts and in open waters inside and outside MPAs. We are using BRUVS to explore previously unknown seamounts outside MPAs, such as around the Cocos, Galapagos, Coiba and Malpelo islands.
Underwater visuals surveys (UVS) are used to estimate the relative abundance of marine megafauna species within and around MPAs. Two divers count all the animals that pass by in a 30-minute period. The census begins at 25 m and ends at 15 m depth ascending gradually during this time. At the same time the current strength and visibility are estimated, water temperature and thermocline are measured.
Photo-identification is used to identify unique individuals visiting a study area and estimate true population size. To achieve this, calculations are made based on the sighting of new and resighting of previously known individuals. Photos are taken of the left-hand cephalic-branchial area of whale sharks and manta rays, and of the tail and dorsal area of whales and dolphins encountered. These photos are submitted to world databases that store and compare data on marine megafauna sightings and identities. For example, whale shark data is constantly uploaded into the ECOCEAN whale shark global data bank (www.whaleshark.org). The photos are also distributed to all the institutions participating for the compilation of local data banks.
Citizen Science: are you planning on diving or snorkeling in the Eastern Pacific. We have developed an App where you can report your encounters with marine megafauna and help us track their distribution and abundance over time. To download the free app and for more information, click here: https://sharkcount.org
Species response to the environment
To assess the behavior and population dynamic response of marine migratory species to changes in the oceanographic setting, we can match remote sensing data with behavioral and population dynamics data. Oceanographic variables that have been considered or are in use are sea surface temperature (SST) obtained from the NOAA’s Optimum Interpolated Sea Surface Temperature, the SST from the EU Copernicus Marine Service Global Ocean Physics Reanalysis; Chlorophyll-a data from the Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua satellites, Chlorophyll-a from the EU Copernicus Marine Service Global Ocean Chlorophyl; the mixed layer density from the EU Copernicus Marine Service Global Ocean Physics Reanalysis; and the eddy kinetic energy (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.
Genetic diversity, gene flow and effective population size
To assess the genetic diversity, gene flow and effective population size between marine species (sub) populations living within MPAs under assessment, DNA tissue collection is carried out. This activity was developed with the aim of building on the pre-existing fish, reptile and marine mammal 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 animal is used. The samples are then preserved in alcohol and labelled.
Furthermore, to assess the diversity of marine species populations living within and beyond MPAs, environmental DNA (eDNA) collection is carried out. Water samples are collected and preserved in Niskin crystal water bottles to preserve DNA fragments left by marine species found in the area. eDNA is a genetic tool developed to assess the species richness of an area based on traces of DNA an individual left behind when swimming freely. The use of eDNA could increase the probability of detecting species that other methods cannot detect.
Animal ethics: handling wildlife with care
All research carried out by MigraMar follows the United States and Australian codes on human and animal experimentation. Our research methods have been reviewed and approved by the Animal Care and Use Committee of the University of California – Davis, and the Safety, Ethics and Institutional Biosafety Committees of the University of Tasmania. Currently, we operate under guidelines of 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 and Energy of Costa Rica.