We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
High microplastic and anthropogenic particle contamination in the gastrointestinal tracts of tiger sharks (Galeocerdo cuvier) caught in the western North Atlantic Ocean
AI summary Read the abstract
Every tiger shark examined in this study of western North Atlantic specimens contained anthropogenic particles in their digestive tracts, with one individual carrying over 1,600 particles. Of the particles chemically confirmed via spectroscopy, 45% were true microplastics, with polypropylene the most common polymer. Tiger sharks' wide-ranging, generalist feeding habits — consuming nearly anything they encounter — make them effective sentinels for ocean plastic pollution, and the high contamination levels found here were the highest reported for any elasmobranch species.
Few studies have documented microplastics (<5 mm) in shark gastrointestinal (GI) tracts. Here, we report microplastic contamination in the tiger shark (Galeocerdo cuvier), an apex predator and generalist feeder, at several different life stages. We examined seven stomachs and one spiral valve from eight individuals captured off the United States Atlantic and Gulf of Mexico coasts (eastern US) and conducted a literature review of publications reporting anthropogenic debris ingestion in elasmobranchs. Specimens were chemically digested in potassium hydroxide (KOH) and density separated using calcium chloride (CaCl) before quantifying and categorizing suspected anthropogenic particles (>45 μm) by size, morphology, and colour. Anthropogenic particles were found in the stomachs and spiral valve of all sharks. A total of 3151 anthropogenic particles were observed across all stomachs with 1603 anthropogenic particles observed in a single specimen. A subset of suspected anthropogenic particles (14%) were chemically identified using Raman spectroscopy and μ-Fourier Transform Infrared spectroscopy to confirm anthropogenic origin. Overall, ≥95% of particles analyzed via spectroscopy were confirmed anthropogenic, with 45% confirmed as microplastics. Of the microplastics, polypropylene (32%) was the most common polymer. Diverse microparticle morphologies were found, with fragments (57%) and fibers (41%) most frequently observed. The high occurrence and abundance of anthropogenic particle contamination in tiger sharks is likely due to their generalist feeding strategy and high trophic position compared to other marine species. The literature review resulted in 32 studies published through 2022. Several methodologies were employed, and varying amounts of contamination were reported, but none reported contamination as high as detected in our study. Anthropogenic particle ingestion studies should continue in the tiger shark, in addition to other elasmobranch species, to further understand the effects of anthropogenic activities and associated pollution on these predators.
More Papers Like This
Microplastics and other anthropogenic fibres in large apex shark species: Abundance, characteristics, and recommendations for future research
AI summary Read the abstract
This study provided the first investigation of microplastics and microfibres in large apex shark species, documenting their presence and characteristics across multiple species. The results confirm that microplastic contamination extends to marine megafauna at the top of the food web.
Tropical sharks feasting on and swimming through microplastics: First evidence from Malaysia
AI summary Read the abstract
Researchers examined microplastic contamination in five tropical shark species from Malaysian waters, finding that 100% of the 74 sharks sampled contained microplastics. A total of 2,211 plastic particles were found in gastrointestinal tracts and gills, averaging about 30 particles per shark, with black fibers being the most dominant type and polyester the most common polymer. The study suggests that microplastic uptake may be gender-related in some shark species.
Investigating the presence of microplastics in demersal sharks of the North-East Atlantic
AI summary Read the abstract
Researchers found evidence of microplastic and anthropogenic fibre ingestion in four demersal shark species from North-East Atlantic waters off the United Kingdom, investigating whether contamination levels varied by species, sex, or body size.
Coupling Gastro-Intestinal Tract Analysis With an Airborne Contamination Control Method to Estimate Litter Ingestion in Demersal Elasmobranchs
AI summary Read the abstract
This study assessed plastic and microplastic ingestion by demersal elasmobranchs (bottom-dwelling sharks and rays) in the Mediterranean, combining stomach analysis with strict airborne contamination controls. By demonstrating that plastic ingestion occurs even in these deepwater predators, the study shows microplastic contamination has reached the upper levels of Mediterranean marine food webs.
Microplastics in Demersal Sharks From the Southeast Indian Coastal Region
AI summary Read the abstract
Researchers examined microplastic ingestion in demersal sharks from the southeast Indian coast, finding widespread contamination across species with fibers and fragments as the most common particle types, indicating that bottom-dwelling sharks are vulnerable to microplastic exposure.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.