2019 Galápagos Marine Iguana Report
Conservation of the endemic Galápagos Marine Iguana: investigating the emerging threat of marine plastic pollution
Jen Jones – Galápagos Conservation Trust (GCT), University of Exeter (UoE)
Juan Pablo Muñoz-Pérez – UNC-Chapel Hill & Universidad San Francisco de Quito (USFQ) Galápagos Science Center and University of the Sunshine Coast (USC)
Overview and Objectives
The goal of this project is to provide a baseline for the current risk of plastic pollution to the Galápagos marine iguana (Amblyrhynchus cristatus) and provide management recommendations for ongoing monitoring. This work follows a desk-based plastics:wildlife risk assessment undertaken in 2018 by the University of Exeter that identified the marine iguana as high risk for ingestion and entanglement. This species is the only marine lizard and is endemic to Galápagos. The IUCN Status for the species is ‘Vulnerable’ although many sub-species are considered ‘Endangered’. Key questions include: (i) Are Marine Iguanas ingesting plastics?; (ii) does location affect the probability of micro and macroplastic exposure and ingestion?; (iii) do plastics affect health? Fieldwork took place between June and September 2019 and lab work is ongoing.
- We have collected data to establish a baseline for plastic contamination across ten distinct marine iguana habitats including four sub-species and four islands (see map of study sites and sub-species sampled).
- We have collected green, red and brown algae samples to provide a proxy for possible ingestion risk of microplastics and other contaminants for marine iguanas (and other algae eating species such as the endangered Galápagos green turtle).
- We have engaged Galápagos National Park staff with the research and shared all protocols to inform ongoing monitoring strategies.
- Supported by the Galápagos Conservation Trust (GCT), we have ensured that the results of this project will be incorporated into the long-term Galápagos Marine Litter Management Plan.
- We have developed a case study for the bilingual educational ‘Discovering Galápagos’ websites and with our partners at the Galápagos Science Center (GSC), have supported two community awareness raising events in San Cristóbal island.
- We have undertaken 98 iguana health surveys and taken scat samples generating a unique dataset to support future iguana studies.
Outcomes and Impact
- Across our ten sites, we have a strong dataset on the abundance and type of large plastic items in coastal zones that may prove an entanglement risk using standardised beach survey methods that have been co-developed with Park Rangers and our wider research network. Microplastic contamination will be profiled in beach sediments, the sea surface and benthic sediments to get a holistic picture of pollution and therefore exposure risk for different iguana populations. This information will allow us to highlight areas of high pollution to focus conservation attention and reduce risks to iguanas and other marine wildlife.
2. At all sites we undertook a habitat survey to assess food availability for marine iguanas. Any plastic interactions with marine algae were recorded e.g. algae growing on plastic debris or plastic fishing lines entangled in marine algae. Samples were taken of green algae for microplastics and heavy metals analysis.
3. All protocols have been documented and have been shared with the Galápagos National Park Directorate. Two rangers have received training during fieldwork, and we have also engaged two further Park rangers with a plastics workshop in Quito in September 2019 where the project was discussed with a group of 35 scientists and managers from the Eastern Pacific region. We also presented some results at the Galápagos Day event in October 2019 in London at the Royal Geographical Society: https://Galápagosconservation.org.uk/Galápagos-day-2019-our-biggest-yet/
4. Following laboratory analysis of the samples, the resulting hotspot risk map and recommendations for ongoing monitoring of the risk of pollution to marine iguanas will be presented to the Galápagos National Park Directorate for incorporation into their Galápagos Marine Litter Management Plan (of which GCT is a strategic advisor), ensuring a long-lasting legacy for the project.
5. We have developed an educational case study resource for GCT’s Discovering Galápagos website for schools which is currently being redesigned for a relaunch in autumn 2020. This will complement existing marine iguana themed resources that are linked to the school curriculum written with fellow researcher, Dr Amy MacLeod. Sixteen families and more than 50 people attended two community events held at the GSC in San Cristóbal to explain the ongoing research and its importance. The attendees took part in different educational activities, among which are significant commitments to protect marine iguanas.
6. The detailed marine iguana health assessment included: Standard measurements, Blood films, Body temperature, Heart rate, Respiratory rate, iSTAT blood values (Chem8), Lactate, Blood spot cards (heavy metals, PCB’s, phthalates), Total bilirubin, Cholesterol, Alanine aminotransferase, Alkaline phosphatase, Albumin, Uric acid, Globulin and Aspartate transaminase. A preliminary assessment of the data indicates that the animals captured and sampled were clinically healthy based on standard vital signs, morphometrics, and blood value data. These values have been compared to published and unpublished data on the marine iguana. The blood spot cards (used to detect toxins and heavy metals) have not yet been analyzed. No abnormalities were found during physical examination. This was a healthy group of mixed age and sex Marine Iguanas.
Juan Pablo undertook a research residency at the University of Exeter, UK in November 2019 to process the iguana scat samples to determine evidence of microplastic ingestion. He also analysed all suspected particles by FT-IR (fourier transform infra-red spectroscopy) increasing the confidence in results
In total, 101 synthetic fibers and fragments were found across the scat samples from 98 animals. Each Marine Iguana scat had 2 – 4 synthetic particles per sample after controls were applied.
- The most common type of synthetic particles found were:
- Alpha- cellulose (99.5% pure) – likely cotton e.g. from clothing
- Nylon – likely from fishing equipment
- Polyester – likely from clothing, possibly fishing gear
- Polyethylene – likely from degraded beach litter
The analysis of the remaining samples will be undertaken when laboratories reopen. We are hopeful that even with the delays from COVID-19, that all samples will be processed and the data analysed by September 2020. We are aiming for a journal submission by December 2020 presenting the results of this project kindly funded by the International Iguana Foundation. This work will continue to have impact as we work to undertake similar risk assessments with other species including the Galápagos green sea turtle and the Galápagos sea lion.