Effects of sea bloom, chattonella antiqua, on gill primary lamellae of the young yellowtail, seriola quinqueradiata.

Abstract

Histological and histochemical alterations on gill primary lamellae of the teleost, young yellowtail (Seriola quinqueradiata), affected by the sea bloom (Chattonella antiqua) were studied and causative factors responsible for fish death were considered in the present work.A significant loss of mucous goblet cells on the afferent ridges occurred within about one hr. Among the remainder, mucous cells located on the afferent ridge of the basal part of the gill primary lamellae were markedly impaired (64% decrease in number). For TEM preparation, hyaline degenerations of the mucous cell membrane were observed.Histochemically, these mucous goblet cells contained neutral and acid glycoproteins.The cell layer on both ridges exposed to sea bloom appeared to be thinner than that of the control.The cell body of the internal multilayered mass was shrunk and intercellular spaces were markedly expanded. These edematous gill lamellae might be caused by the disappearance of the mucous coat, leading to locally impaired osmoregulations. As a result, gas exchange on the gill lamellae might be disturbed.The sea bloom often appearing on the Seto Inland Sea during the summer causes great damage to the fish farms, especially to young yellowtails. The species of plankton causing the sea bloom depend on the time, place, and year. The effects of these organisms on the fish are thought to concern oxygen deficiency (7,11,14). However, the mechanisms leading to fish death are still unknown. In the previous work, the effects of sea bloom (Gymnodinium) on gill primary lamellae of the teleost, young yellowtail (Seriola quinqueradiata) were investigated from the morphological and histochemical point of view (1, 12). As a result, it was found that the mucous coat on the gill and most of the mucous goblet cells located on the afferent ridge disappeared, though they were intact on the efferent ridge. Scanning electronmicroscopically, pavement cells were swollen also on the afferent ridge, while they were intact on the efferent ridge. Chloride and mucous goblet cells with many cellular extensions appeared in the epithelia of the afferent ridge of the primary lamellae. These observations suggest that the causative factors responsible for fish death might be locally impaired osmoregulations on the gill lamellae, leading to the respiratory disorders (oxygen deficiency).

Antioxidant responses and lipid peroxidation in gills and erythrocytes of fish (Rhabdosarga sarba) upon exposure to Chattonella marina and hydrogen peroxide: Implications on the cause of fish kills

“…Physical clogging may lead to over-production of mucus or edema, which were observed in the gills of fish killed by exposure to Chattonella in both laboratory (Shimada et al, 1983;Ishimatsu et al, 1996b;Hishida et al, 1997;Nakamura et al, 1998) and field (Tiffany et al, 2001) conditions. Physical clogging leads to the impairment of oxygen transfer and hence fish kills.…”

Histological Analysis of the Mechanisms of <i>Chattonella</i>-Induced Hypoxemia in Yellowtail

“…Secretion of mucus in response to Chattonella exposure has in fact been repeated ly reported.2,4,10,20) Shimada et al 10) found that loss of mucus from the afferent side of the filament was more pronounced than that on the efferent side. We also noticed such difference between the two sides ( Table 1).…”

Clearance effects of the Pacific oyster Crassostrea gigas on the fish-killing algae Chattonella marina and Chattonella antiqua

“…The genus Chattonella is widely known to be toxic to fish and is especially harmful to young yellowtail Seriola quinqueradiata Temminck & Schlegel (Shimada et al 1983, Toyoshima et al 1985. However, there is no universal agreement on the mechanisms of toxicity of this genus (Landsberg 2002).…”