Inter- and intraspecific variation in anoxic survival among three bivalve species in intertidal and subtidal areas along the coast of Japan

Abstract

Abstract:Basal experiments that examine the impact of hypoxia on bivalves provide an explanation for dominant bivalve population maintenance in hypoxic soft-bottom habitats. We conducted laboratory experiments to assess the effect of persistent anoxia on the survival of three bivalve species: Manila clams (Ruditapes philippinarum), ark shells (Anadara kagoshimensis), and Veremolpa micra. Further, we compared the interspecific variation of ark shells among different habitats in the intertidal and subtidal regions of Ariake Bay and Lake Nakaumi, Japan. A marked inter-and intraspecific variation was detected with respect to survival under anoxic conditions. Specifically, the survival of V. micra and ark shells in Lake Nakaumi under persistent anoxia was significantly higher than that of ark shells in Ariake Bay and Manila clams in Tokyo Bay. Further experiments indicated that ark shell survival (LT 50 ) under persistent anoxia with sulfurization was significantly lower than that under anoxia alone. Such inter-and intraspecific variations in anoxia and sulfurization tolerance might reflect the dominance of certain bivalve species in hypoxic regions.

Impact of sea spider parasitism on host clams: susceptibility and intensity-dependent mortality

“…These results indicate a notable effect of interaction between parasitic infection and lack of food on host clams, supporting that mass mortality of host Manila clam in the field (Tokyo Bay) may not be caused solely by parasitic infection of sea spiders, and might possibly be due to interactive effects between the parasitic infection and other factors, such as lack of food and severe environmental conditions (e.g. hypoxia and low salinity; Wakita et al , 2014; Yamada et al , 2016a).…”

“…historical effect) and to ensure uniform conditions among the Manila clams (cf. Yamada et al , 2016a). A diatom Chaetoceros spp.…”

“…(cell diameter ~5–7 µm), was used to provide an algal diet. A sufficient feeding status of 5–10 × 10 7 cell·clam-g −1 day −1 (Toba & Miyama, 1991; Nakamura, 2004; Yamada et al , 2016a) was offered for 12 h every day until the end of the laboratory experiments. The number of algal cells was counted in a Coulter counter (Coulter Z1, Beckman Coulter, Inc., Tokyo, Japan), and those with a particle diameter of >2.5 µm were regarded as Chaetoceros spp.…”

Population dynamics of a hypoxia-tolerant bivalve: A comparison of two sites in the inner part of Ariake Bay, Japan

“…In the inner part of Ariake Bay, where seasonal hypoxia occurs, V. micra has been reported as a predominant species (Yoshino et al 2010. Additionally, V. micra collected from this region was highly tolerant to anoxic conditions (Yamada et al 2016). According to a long-term survey from 2002 to 2008 in Ariake Bay by Tsutsumi et al (2015), the density of V. micra at Stn A fluctuated greatly and was mainly composed of small individuals, whereas the population of V. micra at Stn B, which was adjacent to Stn A, had a high density and biomass.…”

The killer within: Endogenous bacteria accelerate oyster mortality during sustained anoxia

“…Despite the potential negative ramifications of increased bacterial levels for coastal animals, and the ubiquity of bacteria during summer under low oxygen, this mechanism of mortality remains understudied from an ecological perspective. While there is increasing evidence that bacteria are an important factor affecting bivalve mortality (e.g., Babarro and de Zwaan 2001, 2002, 2008; Yamada et al 2016), there are many uncertainties surrounding whether specific bacteria are responsible for bivalve death or if changes in behavior may limit exposure to stressful environmental conditions and/or bacteria. Given the paucity of information on this subject, it remains unclear what role bacteria play in anoxia‐related mortality, or how bivalves (and coastal organisms in general) respond to this additional stressor under hypoxia/anoxia.…”