Copper Toxicity on Survival, Respiration and Organ Structure of Mactra veneriformis (Bivalvia: Mactridae)

Abstract

This study was conducted to find out the changes of survivorship, respiration and organ structure of Mactra veneriformis exposed to copper (Cu). Experimental period was four weeks. Experimental groups were composed of one control condition and three copper exposure conditions (0.025, 0.050 and 0.100 mg/L). The results of the study confirmed that copper induces reduction of survival rate and respiration rate and histopathology of organ structure of the bivalve. In the copper concentration of 0.100 mg/L, mortality was 100% after Cu exposure of 3 weeks. Respiration rate was observed exposure groups lower than control decline by 75%. Histological analysis of organ system illustrated expansion of hemolymph sinus, disappearance of epidermal layer and degeneration of connective tissue layer of the mantle. Also, histological degenerations as epithelial necrosis and hyperplasia of mucous cells are recognized in the gill and it was observed expansion of hemolymph sinus, disruption of epithelial layer, decrease of mucous cell and degeneration of connective tissue layer in the foot. In the digestive diverticulum, it was showed atrophy of basophilic cell and degeneration of epithelial cell in the digestive tubules, and as the concentration of copper increased the accumulation of lipofuscin increased.

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

“…In the latter case, 36% of males and 25% of females had reached Ripe stage at shell lengths of 21−25 mm. Higher percentages (64% of males and 58% of females with 21−25 mm) were recorded on another sampling occasion in Kunsan (Mature stage in Chung et al 1988). The smallest mature shell length in the Shirakawa population (16.7 mm) is comparable to that in the Kunsan population in which 33% of males and 12.5% of females with 15−20 mm shell lengths were at Mature stage (Chung et al 1988).…”

“…In the Kunsan population, South Korea, there seems to be three recruitment events during June to July (fig. 4 in Ryou and Chung 1995), but no firm records are found for the period from August to September despite the documented reproductive season lasting until September (Chung et al 1988;Chung and Ryou 2000). The time interval between gamete spawning by adults and newly-settled juveniles reaching the smallest size class (class's median shell length, 1 mm) on the Shirakawa sandflat could be 1 month, as estimated from the first date of egg spawning in 2005 (9 May; Fig.…”

“…The sex and the developmental stage of each gonad were examined under an optical microscope and photographed (Olympus SP-350; × 600). The assignment of gonadal stages basically followed the scheme for M. veneriformis given in Chung et al (1988) and Chung and Ryou (2000), with some modifications (see the Discussion): Pre-developmental (stage I), Follicular (stage II), Growing (stage III), Mature (stage IV), Spawning (stage V), Postspawning (stage VI), and Degenerating (stage VII). The gonadal stage-frequency distributions were made for each sampling occasion.…”

“…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.…”

Chronic Effects of Copper on Antioxidant Enzymes and Acetylcholinesterase Activities in Rock bream Oplegnathus fasciatus

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