Growth of Mya arenaria L. at the northern edge of the range: heterogeneity of soft-shell clam growth characteristics in the White Sea

Abstract

Linear growth of soft-shell clams, Mya arenaria L., was studied at six locations in the White Sea situated in the middle and low tidal zones. The main aim was to analyse the growth heterogeneity both within beds (with respect to individual growth) and between beds (with respect to group growth). Mya population was characterized by a slow growth and a long lifespan. Maximum shell size was 70-80 mm, and longevity was at least 25 years. In addition, growth rates were highly variable, statistically significant differences being present both within and between the beds. No differences were found in group growth between different tidal horizons of the same site. The slowest growth of soft-shell clams was observed at sites with the greatest content of fine particles (silt and clay) in sediments. Differences between beds in Mya group growth could reflect variability of feeding conditions, which were probably determined by some local features (e.g. hydrodynamic regime). However, the variation of the individual growth rate within beds was comparable to that of the group growth rate between studied locations. To a great extent it seemed to be determined by the characteristics of the initial period of soft-shell clam growth.

Distribution and growth of bivalve molluscs Serripes groenlandicus (Mohr) and Macoma calcarea (Gmelin) in the Pechora Sea

“…The differences in molluscan growth at the early stages can be associated with the conditions of spat formation. The correlation between the size by the start of the second growth season and later growth rate (during the entire life cycle) was shown for several bivalve species such as Mytilus edulis (Maximovich et al 1993), Mytilus trossulus (Gagaev et al 1994), Macoma balthica (Cloern and Nichols 1978) Macoma incongrua (Maximovich and Lysenko 1986) and Mya arenaria (Gerasimova et al 2016(Gerasimova et al , 2017. In S. groenlandicus and M. calcarea the differences in size by the start of the second growth season could be caused by the difference in the time of juvenile settling due to prolonged (up to 2-4 months) reproduction period in the northern seas (Ockelmann 1958;Petersen 1978;Günther and Fedyakov 2000;Garcia et al 2003).…”

“…For several bivalve species at the White Sea, an almost linear dependence of the growth rate on the size of the first growth ring is shown (Gerasimova et al 2003(Gerasimova et al , 2014(Gerasimova et al , 2016(Gerasimova et al , 2017. Accordingly, it can be assumed that individuals that have reached a larger size before their first winter will grow faster afterwards.…”

“…As noted above, practically nothing is known about the variability of individual growth rate of M. calcarea and S. groenlandicus. However, there are more data on other bivalve species, e.g., Mytilus edulis (Kulakovskii and Kunin 1982;Sukhotin 1992;Sukhotin and Kulakowski 1992;Gerasimova et al 2014), Mytilus trossulus (Gagaev et al 1994); Macoma balthica (Cloern and Nichols 1978); Macoma incongrua (Maximovich and Lysenko 1986); and Mya arenaria (Gerasimova et al 2016(Gerasimova et al , 2017. The differentiation of individual growth of S. groenlandicus and Macoma calcarea apparently occurred early in the life cycle and persisted afterwards.…”

Distribution and density of Lutraria rhynchaena Jonas, 1844 relate to sediment while reproduction shows multiple peaks per year in Cat Ba-Ha Long Bay, Vietnam

“…The clams were not found on coarse silt or fine silt substrate types, although these are the dominant substrate types within the study area. Substrate type influences the distribution of macro-benthic communities [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. For example, Mya arenaria with burrowing behaviour similar to L. rhynchaena primarily inhabits sand and mud substrates [ 24 ], with higher densities being observed in sand substrates [ 25 ].…”

“…For example, Mya arenaria with burrowing behaviour similar to L. rhynchaena primarily inhabits sand and mud substrates [ 24 ], with higher densities being observed in sand substrates [ 25 ]. In some cases, growth rates of clams can be impacted by sediment type, with slower growth rates being associated with the sites comprising greater contents of fine particle (silt and clay) sediments [ 20 ]. Certain substrate compositions provide bivalves with refuge against predators.…”