Growth and reproduction in the Antarctic brooding bivalve Adacnarca nitens (Philobryidae) from the Ross Sea

Abstract

We present information on the reproductive biology, population structure, and growth of the brooding Antarctic bivalve Adacnarca nitens Pelseneer 1903, from the Ross Sea, Antarctica. Individuals ranging from 0.85 to 6.00 mm were found attached to a hydrozoan colony. This species shows low fecundity and large egg size, common to other brooding species. The minimum size at which oogenesis was detected was 2.3 mm and the minimum size at which brooding was evident was 3.9 mm. Embryos of a full range of developmental stages were brooded simultaneously in females. The population showed a log-normal distribution and results suggest non-periodic reproduction with continuous embryonic development. The reproductive traits of A. nitens are discussed in the context of circumAntarctic species distribution and limitations to dispersal in brooding benthic invertebrates.

Plasticity in shell morphology and growth among deep-sea protobranch bivalves of the genus Yoldiella (Yoldiidae) from contrasting Southern Ocean regions

“…Yager, P.L., Sherrell, R.M., Alderkamp, A.C., Schofield, O., Ducklow, H., Arrigo, K.R., Bertilsson, S., Lowry, K.E., Moknes, P.O., Ndungu, K., Post, A.F., Randall-Goodwin, E., Riemann, L., Severmann, S., Thatje, S., Van Ducken, G.L., Wilson, S., 2012 (Brey and Hain, 1992), Lissarca miliaris (Richardson, 1979), and Adacnarca nitens (Higgs et al, 2009 (Gage, 1994). and South Atlantic (n=15); c, f) Yoldiella valettei from the Amundsen Sea (n=22), Scotia Sea (n=22), and Weddell Sea (n=22).…”

“…Only lines that could be traced around the whole length of the shell were counted (Brey and Hain, 1992;Higgs et al, 2009). To confirm subtle growth lines, 20 individuals of each species from each area, covering the full size range of the sample, were selected for analysis using a Scanning Electron Microscope (SEM).…”

“…Size-at-age data were analysed using the von Bertalanffy growth function (vBGF); -e -k(t-t0) where S t is length, S is asymptotic length, K is growth coefficient, t is age and t 0 is age when size equals zero. This method, commonly used for fish growth analysis, has more recently been used for bivalve growth (Brey and Hain, 1992;Brey, 2001;Heilmayer et al, 2004;Brey et al, 2011;Higgs et al, 2009). As individual growth is non-linear, it is difficult to compare the overall growth between individuals.…”

“…5.2mm) than Y. ecaudata (3.3mm). Assuming growth increments represent a constant time increment, both species demonstrate slower growth than the three filter feeding philobryid bivalves Adacnarca nitens (Higgs et al 2009), Lissarca notorcadensis (Brey and Hain 1992), and Lissarca miliaris (Richardson 1979) …”

The reproductive ecology of the Antarctic bivalve Aequiyoldia eightsii (Protobranchia: Sareptidae) follows neither Antarctic nor taxonomic patterns

“…The reproductive patterns of Antarctic shallow-water benthos are often characterised by a prolonged reproductive cycle (18-24 months), lecithotrophy, and direct development, low fecundity, and seasonal reproductive patterns (Clarke 1979;Brey and Hain 1992;Chiantore et al 2002;Grange et al 2004Grange et al , 2007Higgs et al 2009;Pearse et al 2009;Reed et al 2013a). However, a few species also demonstrate shorter gametogenic periods (12 months or less) (Clarke 1988;Chiantore et al 2002;Tyler et al 2003;Grange et al 2011), planktotrophic larvae (Stanwell-Smith et al 1999;Bowden et al 2009), and relatively high fecundity (McClintock and Pearse 1986;Bosch and Pearse 1990;Grange et al 2004;Orejas et al 2007).…”