Barnacle Epibiosis on Sea Turtles in Korea: A West Pacific Region With Low Occurrence and Intensity of Chelonibia testudinaria (Cirripedia: Chelonibiidae)

Abstract

Loggerhead and green turtles inhabit all oceans except the polar regions. External surfaces of sea turtles are often colonized by epibiotic chelonibiid barnacles. Barnacle taxonomy studies in Korea began in 1985, but until present, no turtle barnacles were recorded. This suggests that either the diversity and frequency of occurrence of turtle barnacles in Korean waters are low or the turtle barnacles have been understudied. This study complies with data collected over 6 years of sea turtle stranding events in Korea (2015–2020). We examined the diversity, frequency, and intensity of turtle barnacle occurrence. Of the 55 recorded strandings, loggerhead turtles were the most common (58%), followed by green turtles (33%). Only one species of barnacle, Chelonibia testudinaria, was found on both loggerhead and green turtles. The frequency of barnacle occurrence on loggerhead turtles was 28%, with an intensity of 2.4 ± 2.7 barnacles per turtle. Notably, 11% of green turtles had barnacles, with an average of one individual per turtle. The frequency and intensity of barnacle occurrence on green turtles analyzed in this study were five times lower than that on green turtle populations in Okinawan, Bornean, and Australian waters in the Indo-Pacific. Based on these new data and the available literature, we speculated that the barnacle larval pools in cold, high-latitude Korean waters are smaller than those occurring in other locations in the Indo-Pacific. The frequency and intensity of occurrence of barnacles on loggerhead turtles in Korea fall within the range recorded in other Indo-Pacific locations. The longer migratory routes of loggerhead turtles allow them to pass through different larval pools in the Indo-Pacific water, exposing them to higher barnacle abundances.

Variations in body condition of green turtles (Chelonia mydas) in two nearby foraging grounds indicate their sensitivity to foraging habitats

“…Higher occurrence and abundance of C. testudinaria in Kudat Mainland than Balambangan Island aggregations can also be explained if nutrient supply and availability were higher in the coastal waters of the Kudat Mainland. Barnacle occurrence and abundance are known to differ between sea turtle species (Lim, Syed Hussein & Palaniappan, 2020; Boyd et al, 2021) and aggregations (Boyd et al, 2021; Kim et al, 2022). Low water temperature is one of the factors for the low occurrence and abundance of barnacles (Kim et al, 2022), but persistent differences in water temperature among nearby aggregations are unlikely.…”

“…Barnacle occurrence and abundance are known to differ between sea turtle species (Lim, Syed Hussein & Palaniappan, 2020; Boyd et al, 2021) and aggregations (Boyd et al, 2021; Kim et al, 2022). Low water temperature is one of the factors for the low occurrence and abundance of barnacles (Kim et al, 2022), but persistent differences in water temperature among nearby aggregations are unlikely. In contrast to previous research, the higher abundance of barnacles on larger turtles was not supported, but this has been observed elsewhere (Hayashi & Tsuji, 2008; Lim, Syed Hussein & Palaniappan, 2020).…”

The host range and distribution pattern of rhizocephalan parasitic barnacles in Korean coasts and their relationship with geographical factors

“…Due to the highly degenerated morphological features of rhizocephalan species (Høeg, 1992;Høeg & Lützen, 1995;Øksnebjerg, 2000) that often make species identification very challenging, the author also determined mtDNA cox1 sequences as molecular evidence of their correct identification. Afterward, the decapod host and distribution of each identified Rhizocephala were confirmed based on the three Korean coast ecoregions, i.e., Yellow Sea, East China Sea, and East Sea (Kim et al, 2020;2022). The author analyzed the relationship between Rhizocephala and its host and the diversity of Rhizocephala in each marine ecoregion to confirm trends and special features of the results.…”

“…To fill the gap in our knowledge, an extensive examination of three host taxa-Gebiidea, Anomura, and Brachyura-sampled from 28 locations representing three marine ecoregions of (Kim et al, 2020;2022) was performed, building upon previous work of Jung et al (2019;2021) 1 . Due to the highly degenerated morphological features of rhizocephalan species (Høeg, 1992;Høeg & Lützen, 1995;Øksnebjerg, 2000) that often make species identification very challenging, the author also determined mtDNA cox1 sequences as molecular evidence of their correct identification.…”

Connectivity between sea turtles off Jeju Island on the Korean Peninsula, and other populations in the western Pacific

“…Jeju Island on the Korean Peninsula is the northern boundary for most sea turtle species inhabiting the western Pacific region and has been recognized as a foraging ground for green (Chelonia mydas) and loggerhead turtles (Caretta caretta) (Jung et al, 2012b;Jang et al, 2018). To date, all five species of sea turtles reported in the northwestern Pacific have also been observed in the waters around the Korean Peninsula: green, loggerhead, hawksbill (Eretmochelys imbricata), olive ridley (Lepidochelys olivacea), and leatherback turtles (Dermochelys coriacea) (Kim et al, 2017;Kim et al, 2022). Satellite tracking data of green turtles suggest that the aggregation off Jeju originates from neighboring rookeries in Japan, Taiwan, and China (Moon et al, 2011;Jang et al, 2018).…”