Land Use, Macroalgae, and a Tumor-Forming Disease in Marine Turtles

Wildlife diseases are an increasing concern for endangered species conservation, but their occurrence, causes, and human influences are often unknown. We analyzed 3,939 records of stranded Hawaiian green sea turtles (Chelonia mydas) over 28 years to understand fibropapillomatosis, a tumor-forming disease linked to a herpesvirus. Turtle size is a consistent risk factor and size-standardized models revealed considerable spatial and temporal variability. The disease peaked in some areas in the 1990s, in some regions rates remained constant, and elsewhere rates increased. Land use, onshore of where the turtles feed, may play a role. Elevated disease rates were clustered in watersheds with high nitrogen-footprints; an index of natural and anthropogenic factors that affect coastal eutrophication. Further analysis shows strong epidemiological links between disease rates, nitrogen-footprints, and invasive macroalgae and points to foraging ecology. These turtles now forage on invasive macroalgae, which can dominate nutrient rich waters and sequester environmental N in the amino acid arginine. Arginine is known to regulate immune activity, promote herpesviruses, and contribute to tumor formation. Our results have implications for understanding diseases in aquatic organisms, eutrophication, herpesviruses, and tumor formation

National Oceanic and Atmospheric Administration Report 54

This document summarizes the findings from the 2015 International Summit pm Fibropapillomatosis (FP) convened in Honolulu, Hawaii June 11-14, 2015. The purpose of this convention was to provide a forum to assess the status and trends of the disease globally and its demographic impact on sea turtles

Marine Sponges, Other Animal Food, and Nonfood Items Found in Digestive Tracts of the Herbivorous Marine Turtle Chelonia mydas in Hawai‘i

v. ill. 23 cm.Also available through BioOne: http://www.bioone.org/doi/abs/10.2984/65.3.375QuarterlyAlthough the usual diet of Chelonia mydas comes from algae and sea grasses (plant material), animal material has been found in samples taken over the past 35 yr. The small black-brown protein sponge Chondrosia chucalla resembles the alga Codium arabicum in size, color, and texture, and both grow next to each other on the reefs. We hypothesize that turtles are actively seeking and eating these sponges and not mistaking them for C. arabicum. Both protein and silica sponges occur in the diet of Chelonia, but only 6.8% of the time are eaten in addition to their usual plant diet. Thirty different kinds of other animals were found in the samples, including Cnidaria, Mollusca, Crustacea, Insecta, Echinodermata, squid, fish, tumor flesh, and other animals but in low frequency (5%). Most of the miscellaneous nonfood debris items were terrestrial leaves, plastic, paper, string, fibers, hair, and paint chips but also in low frequency (<7%). Among animal food items known to have nutritional value, the protein sponge C. chucalla could be contributing an important nutritive factor, but this needs further research