An unknown species of Leucochloridium (Trematoda: Leucochloridiidae) from northern Honshu, Japan.

Pulsating broodsacs of Leucochloridium sp. (Trematoda: Leucochloridiidae) were found from amber snails (Succinea lauta) in Iwate, the northern part of Honshu, Japan. A pattern with red-brown vertical stripes was characteristic of the broodsac. Very similar broodsacs were already detected from Okinawa Islands, the southern archipelago of Japan, and tentatively identified as Leucochloridium cf. passeri. A phylogenetic analysis based on DNA sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) showed that Leucochloridium sp. is different at species level from L. cf. passeri and that both species are related to Leucochloridium vogtianum from Europe. In this study the definitive identification of larval Leucochloridium sp. was impossible, but the resulting phylogeny confirmed that at least 4 species of Leucochloridium are distributed in Japan, depending on locality and climate. The DNA barcode generated in this study will be useful in detecting the adult stage of Leucochloridium sp. from birds.

Comparative age-specific demography of four commercially important deep-water snappers: implication for fishery management of a long-lived lutjanid.

Lutjanid snappers belonging to the subfamilies Apsilinae and Etelinae are commercially valuable components of tropical deep-water fisheries throughout much of the Indo-Pacific region. Based on age assessment using sagittal otoliths, the age-specific demographic characteristics of four deep-water snappers, Etelis coruscans, Paracaesio caerulea, Pristipomoides filamentosus and Pristipomoides sieboldii, in the Okinawa Islands, southwestern Japan, were examined, and the results were discussed for fishery management. Age validation using edge-type analysis demonstrated that opaque zones in all species were formed once per year and were considered valid annual growth increments. The von Bertalanffy growth equations were also determined for each species. These snappers are long-lived (>50 years for E. coruscans and P. caerulea and >30 years for the two species of Pristipomoides) and relatively slow-growing. The age of acquiring sexual maturity in females was relatively later in E. coruscans, P. caerulea and P. filamentosus than in P. sieboldii. The results revealed differences in the biological traits among these four species; E. coruscans and P. caerulea with long life spans and late maturation are particularly more vulnerable to fishing impact than the two Pristipomoides species. Therefore, further approaches to decrease and control fishing intensity, such as networking of marine-protected areas and regulation to control the numbers of boats and/or the total allowable catch, are necessary for the management of the stock of these species, especially for E. coruscans and P. caerulea.