Comparison of Development and Larval Growth of Four Venerid Clams

Abstract

The development and larval morphology of four venerid calms, Ruditapes phibppinurum, Muctru veneriformis, Cyclinu sinensis, and Meretrix lusoriu, which cohabit the intertidal zone in western coastal Korea, were compared using laboratory culture techniques. At 87 pm, the fertilized eggs of C. sinensis and M. Iusoriu were the largest and at 53 pm, those of M. venervorm's were the smallest. D-shaped larvae of M. lusoriu were the largest and those of M. veneriform's were the smallest measuring at 135 pm and 89 pm, respectively. D-shaped larvae of R. philippinurum and M. lusoriu had symmetrical shoulder angles and an elliptical ventral form, in contrast to the asymmetrical shoulder angles and round ventral forms of M. veneriformis and C. sinensis. In general, pediveliger larvae of all species in the study were yellow, but those of M. veneriforks and C sinemis were a more pronounced yellow. In between the early D-shaped and pediveliger stage, 7 and 17 d elapsed for M. lusoniu and C. sinensis larvae, respectively. In the early larval stages for all species, the sheU length was longer than the height. However, shell length and height later became approximately the same size in all species except R. philippinurum, which exhibited a flat shape. These results indicate that for these four venerid clams, the different characteristics in larval growth and external morphology provide the evidence necessary for larval identification of natural seed production despite the fact that they spawn concurrently in the intertidal zone.

Spawning induction and embryonic development of the clam Ameghinomya antiqua (King, 1832)

“…The embryonic development of A. antiqua follows the pattern described for bivalve mollusks, where the first, second, and third division stages are achieved, followed by the state of morula, blastula, rotating blastula, gastrula, and trochophore (Reverol et al 2004, Hur et al 2005, Da Costa et al 2008, Aranda-Burgos et al 2014, Contreras-Guzmán et al 2014, Barría et al 2021. Nevertheless, in A. antiqua, the jelly coat disappears after the oocyte is fertilized, unlike T. elliptica (Barría et al 2021), where this layer disappears in the stage of gastrula-trochophore, and G. solida, the jelly coat remains during the complete embryonic cycle (Contreras-Guzmán et al 2014).…”

“…In Tawera elliptica and Tivela mactroides the best results have been achieved with biological induction with gonad extract (Reverol et al 2004, Barría et al 2021 and in Venerupis pullastra with desiccation (Cerviño 2011). On the other hand, other authors have used a mix of thermal shock, food and gonadal extract, and a combination of thermal shock and desiccation (Hur et al 2005, Cerviño 2011, Aranda-Burgos et al 2014, Contreras-Guzmán et al 2014. They achieved spawning in Gari solida, R. philippinarum, Venerupis pullastra, Cyclina sinensis, and Metrix lusoria.…”

Life history and population dynamics of the surf clam, Mactra veneriformis (Bivalvia: Mactridae), on an estuarine intertidal sandflat in western Kyushu, Japan

“…7). The duration of planktonic larvae to reach the competent pediveliger stage at 22.0ºC was reported to be 14 days (Hur et al 2005). Around the head of Ise Bay, central Honshu, Japan, a high-density larval assemblage was followed by an assemblage of high-density newly-settled juveniles with a 0.3 mm shell length, with time-lags varying from 0.6 month (from beginning to end of August) to 3.1 months (beginning of August to beginning of November) (Nanbu et al 2006).…”

“…In Japanese waters, it occurs from northern Honshu Island to the Shikoku and Kyushu Islands (Okutani et al 2000;Koga et al 2005) and is one of the dominant species of the benthic community on tidal flats in large estuaries such as Tokyo Bay (Hiwatari et al 2002), Ise Bay in central Honshu (Nanbu et al 2006), and Ariake Sound in western Kyushu (Tamaki et al 2008). Various biological or ecological traits of M. veneriformis have been investigated, including population genetic structure (Hou et al 2006), reproduction (Iwata 1948;Chung et al 1988;Chung and Ryou 2000), trematode infection (Han and Chai 2008), larval development (Hur et al 2005), coupling of larval and juvenile abundances (Nanbu et al 2006), recruitment, individual growth, and survivorship (Kim and Ryou 1991;Ryou and Chung 1995;Ryou 1997), food sources (Kasai et al 2004;Yokoyama et al 2005), body biochemical compositions (Shiraishi 2006), assimilation efficiency and benthic-pelagic coupling for nitrogen budget (Hiwatari et al 2002), influences of water turbidity on survival (Chang and Chin 1978;Ahn and Choi 1998), and the effect of water salinity on burrowing, feeding, and growth (Nakamura et al 2005). Of these studies, those related to population dynamics have previously concentrated mostly on the west coast population in South Korea facing the Yellow Sea, in particular in tidal flats around Kunsan.…”

Quantification of Reproductive Effort and Microscopic Observation on the Larval Development of Manila clam Ruditapes philippinarum (Adams and Reeve, 1850)

“…성 성숙은 수온 및 염분과 같은 환경인자와 더불어 먹이생물의 계절적 변화와도 밀접한 관계를 갖는 것으로 알려져 있다 (Kang et al, 2000(Kang et al, , 2010 (Hur et al, 2005). 바지락 유생발생 과정은 생활사는 모패 로부터 방출된 정자와 난자의 수정에 의한 극체 (polar body) 형성, 2,4,8,16 세포세포분열, 상실기 (morula) 및 운동성을 가 지게 되는 포배기 (blastula), 낭배기 (gastrula), 자유 유영 생 활을 하는 담륜자 유생기 (trochopore larvae) 를 거쳐 스스로 먹이활동을 시작하는 D 상유생기, 포복피면자유생 (pediveliger) 단계를 거쳐 최종적으로 족 (foot) 및 사이폰이 형성되고 먹이 섭식을 시작하는 post-set 단계로 구분된다 (Hur et al, 2005). 바지락 유생 발생에 영향을 미치는 환경 인자는 수온과 염분 및 먹이 등으로 알려지고 있으며, 특히 수 온에 따라 그 발달단계가 빨라지거나 느려지는 것으로 알려지 고 있다 (Zhang and Yan, 2006…”