Caged fiddler crabs, Uca pugilator, were exposed to field ULV applications to measure the impact of fenthion. Two nozzle systems, conventional flat-fan nozzles (Tee Jet 8002SS) and high-pressure hydraulic nozzles (1/8 MIS), were compared using single spray swaths. Fenthion residues were detected throughout the 4.83-km test zone for both systems. Heavy ground deposits (650-1,670 microg/m2) of fenthion were found within 1 km using the flat-fan nozzle systems, which resulted in 80% fiddler crab mortality. Less than 100 microg/m2 fenthion ground deposits were detected during the high-pressure nozzle trials. No fiddler crab mortality was observed within the first 1-km zone following 3 single swath applications repeated during 3 consecutive nights. We found also that when the fiddler crabs were exposed to 700-800 microg/m2 fenthion, mortality occurred. Significant crab mortality (>50%) was observed when residues exceeded 1,000 microg/m2.
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Mar Pollut Bull
December 2024
School of Biology, Scottish Oceans Institute, University of St Andrews, KY16 8LB, UK.
The Indo-West Pacific region has a rich fiddler crab fauna. In East Asia, some species of fiddler crabs, such as Tubuca coarctata (H. Milne Edwards, 1852) and T.
View Article and Find Full Text PDFThe spoon-tipped (ST) setae coverage and their abundance on the second maxillipeds as well as the morphology of the urocardiac and zygocardiac ossicles from the gastric mills of the four ocypodid species, viz., Austruca annulipes (H. Milne Edwards, 1837), Gelasimus vocans (Linnaeus), 1758, two typical deposit-feeding fiddler crabs, Petruca panamensis (Stimpson, 1859), an atypical herbivorous-cum-'sediment swallower' fiddler crab, and Ocypode ceratophthalmus (Pallas, 1772), an omnivorous ghost crab, were described and compared in relation to their respective trophic habits.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
Université de Mayotte, 8 Rue de L'Université, BP 53, 97660, Dembeni, Mayotte, France.
At land-sea interface, mangroves are likely to be exposed to pesticides due to agricultural run-offs. In Mayotte Island (Comoros archipelago, Mozambique Channel), dimethoate (DMT) is found in high concentrations in tomatoes, but no data confirm its presence in mangroves. We aimed at screening the presence of DMT in three mangroves of Mayotte at different levels (highest point above crops, village, upstream mangrove, downstream mangrove) and assessing the impact of DMT coupled with reduced salinity on mangrove crab physiology.
View Article and Find Full Text PDFEcology
December 2024
Duke University Marine Lab, Beaufort, North Carolina, USA.
Predators regulate communities through top-down control in many ecosystems. Because most studies of top-down control last less than a year and focus on only a subset of the community, they may miss predator effects that manifest at longer timescales or across whole food webs. In southeastern US salt marshes, short-term and small-scale experiments indicate that nektonic predators (e.
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