Environment: peculiar pigment cell neoplasm in fish

Area of Science:

• Environmental toxicology
• Ichthyology
• Marine biology

Background:

• Chromatophoroma, a fish neoplasm, exhibits unusual geographic distribution.
• Previous studies suggest environmental chemicals contribute to chromatophoroma in croaker (Nibea mitsukurii).

Purpose of the Study:

• To investigate the role of environmental chemicals in the etiology of chromatophoroma in Nibea mitsukurii.
• To establish a link between industrial pollutants and pigment-cell neoplasms in fish.

Main Methods:

• Induction of chromatophoroma in tank-reared N. mitsukurii using known carcinogens (e.g., 7,12-dimethyl-benz(a)anthracene).
• Comparative analysis of pigment-cell hyperplasia in catfish (Protosus anguillaris) and N. mitsukurii chromatophoroma.
• Monitoring of chromatophoroma incidence before and after sediment remediation.
• Analysis of mutagenic substances in factory wastewater and subsequent exposure studies on catfish.

Main Results:

• Chromatophoroma was successfully induced in N. mitsukurii using specific carcinogens.
• Pigment-cell hyperplasia in catfish showed similarities to N. mitsukurii chromatophoroma.
• Fish neoplasm incidence decreased significantly after removing contaminated sediment (47% to 20%).
• Factory wastewater contained mutagens (chloroacetones, glyoxals) that induced pigment-cell hyperplasia in catfish.

Conclusions:

• Environmental chemicals, particularly industrial pollutants, are strongly implicated in the development of chromatophoroma in croaker.
• Sediment remediation and wastewater management are crucial for reducing fish neoplasm incidence.
• The study highlights the ecotoxicological impact of industrial discharge on aquatic ecosystems.