Rajids ovipositing on marine litter: A potential threat to their survival.

Marine litter is a complex environmental issue threatening the well-being of multiple organisms. In the present study, we present an overlooked pathway by which marine litter interaction with certain ovigerous skates (Family: Rajidae) communities could compromise their survival. We propose that skates from the genus Sympterygia deposit their egg capsules on marine litter substrates by accident, which are then washed ashore still unhatched. We conducted 10 monitoring surveys on three beaches of La Libertad Region, on the north coast of Peru, looking for marine litter conglomerates to determine the presence of egg capsules. We registered a total of 75 marine litter conglomerates, containing 1595 egg capsules, out of which only 15.9 % were presumably hatched, and 15.8 % were still fresh. Fishing materials were identified as the main item in marine litter conglomerates. We conclude that this behavior could contribute to the decline of Sympterygia communities, although further research is needed.

First record of plastiglomerates, pyroplastics, and plasticrusts in South America.

Beaches in the Anthropocene carry the heavy burden of human-derived pollution, like that induced by plastic litter. For decades, plastic debris has been classified based on its source or physical size. In recent years, studies described and documented new forms of plastic formations, including plastiglomerates, plasticrusts, and pyroplastics. However, reports of these newly described formations are substantially lacking. Therefore, in the present study, we reported the first evidence of plasticrusts (plastic encrusting rock surfaces), plastiglomerates (organic/inorganic composite materials in a plastic matrix), and pyroplastics (burned and weathered plastics) in Peru. The plastic pollutants were recovered from the field through marine litter surveys on four beaches where illegal litter burning and campfires take place. All the suspected plastic formations were analyzed and confirmed using Fourier transformed infrared (FTIR) spectroscopy, and one of each type was analyzed by X-Ray fluorescence (EDX) spectrometry. Plastiglomerates consisted of a high-density polyethylene (HDPE) or polypropylene (PP) matrix with rock and sand inclusions. Pyroplastics were found in various stages of weathering and consisted of various polymers, including HDPE, PP, polyethylene terephthalate (PET), and polyamide (PA). Interestingly, our field observations suggest a new plasticrust formation pathway based on plastic burning and filling of rock crevices with molten plastic. The latter was identified as either PP or HDPE. Elements typically found in the sand and seawater (e.g., Na, Cl, Ca, Si, Fe) were identified on the surface of the plastic formations, as well as others that could potentially be associated with the leaching of additives (e.g., Ti, Br). Although the present study contributed to the knowledge concerning the occurrence of the new types of plastic formations, as well as possible formation pathways, there are still many questions to answer. Hence, we encourage future studies to focus on the toxicity that new plastic formations may induce in contrast with conventional plastics, the release of secondary contaminants (e.g., microplastics, additives), and their degradation in the environment. Lastly, standardized sampling and data treatment protocols are required.