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The reliable quantification of microplastic contamination in chitinous organisms requires validated methods to remove interfering complex organic and inorganic material. This study trialled KOH, H 2 O 2 and HNO 3 digestion methods on the digestive tracts of two large decapods (Panulirus cygnus and Portunus armatus) to validate a protocol that facilitates reliable microplastic extraction. KOH digestion provided the best recovery (>95 %) of all polymers (e.g. polyamide, polyethylene, polyethylene terephthalate, polypropylene, polystyrene and polyvinyl chloride), with the lowest impact to their physical morphology and chemical spectra. While HNO 3 , and HNO 3 + H 2 O 2 treatments were more effective at digesting chitin, they destroyed polyamide, and altered several other polymers. High digestion efficiency did not result in high matrix clarification or high microplastic recovery for large decapods. This study emphasises the importance of validating species-specific microplastic extraction methods, whilst proposing additional post-digestion protocols, such as density separation, for complex samples, that can be applied in future research investigating plastic contamination in large decapods. • KOH provided best recovery of microplastics from digestive tracts of large decapods. • High digestion efficiency (HNO 3 /H 2 O 2) did not result in high polymer recovery. • Specific method protocols depend on sample composition. • Density separation is needed when digestive tracts contain sediment. [ABSTRACT FROM AUTHOR]

Abstract The frequency of disease within coral communities was evaluated using an 18-month series of coral photographs taken before, during, and after a major dredging program at Barrow Island, off Australia's northwest coast. Up to 60 corals were assessed repeatedly at each of four dredging 'impact' sites (<1 km from dredging), and four 'reference' sites (>20 km from dredging). Contrary to an earlier report, the frequency of occurrence of coral disease (usually <5% of corals) was not significantly altered by dredging. The pattern of occurrence of coral disease does not constitute a suitable early warning bioindicator of dredging impacts on coral. This study suggests that disease is difficult to measure and evaluate, and is not a key indicator in the potential impacts of dredging on coral health. We propose that environmental monitoring during dredging should continue to focus on known impact indicators. Highlights • Investigation showed no increase in coral disease during or after a large dredging program. • Disease may occur naturally in many coral communities without much impact. • Coral disease is not a suitable indicator of dredging impacts. • Visual diagnosis of some coral diseases may be unreliable. [ABSTRACT FROM AUTHOR]