Spatial variation in the abundance and condition of the bivalve Nuttallia olivacea in relation to environmental factors and sublethal predation

Abstract

Our aim was to assess the spatial heterogeneity in the abundance and condition of the tellinacean bivalve Nuttallia olivacea in estuarine tidal flats, as well as to reveal the relationships between these variables and abiotic and biotic factors. The intensity of sublethal siphon predation by juvenile stone flounder Platichthys bicoloratus was considered as a possible factor affecting the bivalve condition. A 2-scale sampling of stations at 200 to 800 m intervals and 2 to 5 plots at 5 to 20 m intervals on a transect line at each station was conducted in the Natori River estuary, Japan. Abundance and somatic condition greatly varied at both scales. Densities varied from 0 to 4902 ind. m -2 among stations and from 2480 to 6448 ind. m -2 among plots at the station with the highest density. Body mass index varied from 4.0 to 5.0 between stations and from 4.9 to 5.7 between plots at the station with the highest body mass. It was commonly observed that N. olivacea was abundant and that body condition was high at sites with low silt-clay contents and low elevations, as revealed by generalized linear models. A negative influence of siphon predation was detected only on somatic condition, but it accounted for only 1.2% of the variation, whereas environmental variables accounted for 30.2%. These results indicate that environmental variables are key factors affecting bivalve abundance and condition, while sublethal predation is only a potential factor affecting bivalve condition.

Impacts of the 2011 Tsunami on Sediment Characteristics and Macrozoobenthic Assemblages in a Shallow Eutrophic Lagoon, Sendai Bay, Japan

“…japonica survived the tsunami, although the population size decreased. This species occurred abundantly in sandy unconsolidated sediments forced by high water currents [ 28 ]. In the Nanakita River estuary, this species was also highly abundant on unconsolidated sandy bottoms in the tidal channel and outside the levee [ 18 , 19 ].…”

Seasonal and spatial variations in prey utilization and condition of a piscivorous flatfish Paralichthys olivaceus

“…Initial explanatory variables were the same except for 'season'. All response variables were fitted with a GLMM with a Gaussian error structure and log-link function, similar to the GLMs presented by Tomiyama et al (2010). The GLMMs were constructed and finalized by stepwise backward selection based on the AIC.…”

A suite of essential biodiversity variables for detecting critical biodiversity change

“…However, as it reflects the health status of animals, it also indicates the occurrence of microbial pathogens and parasites as well as plant food sources and is therefore more comprehensive than implied. BMI is used widely across all animal groups [invertebrates (Sheppard et al, 2009;Tomiyama et al, 2010;Johnson et al, 2014); fish (Kolm, 2002;Macedá-Veiga et al, 2014); amphibians (Bancila et al, 2010); birds (Chastel et al, 1995;Karell et al, 2008;Labocha & Hayes, 2012); mammals (Ozgul et al, 2010;Peig & Green, 2010;Rode et al, 2010)]. However, the ecological literature contains a substantial number of alternative indices for BMI (Peig & Green, 2010;Labocha & Hayes, 2012;Macedá-Veiga et al, 2014).…”