Endocrine disruption in fish: An assessment of recent research and results

This report provides an assessment of recent investigations into endocrine disruption in fresh and saltwater species of fish. Most work to date has concen-trated on reproductive endocrine disruption. Laboratory studies have shown a variety of synthetic and natural chemicals including certain industrial intermediates, PAHs, PCBs, pesticides, dioxins, trace elements and plant sterols can interfere with the endocrine system in fish. The potency of most of these chemicals, however, is typically hundreds to thousands of times less than that of endog-enous hormones. Evidence of environmental endocrine disruption ranges from the presence of female egg proteins in males and reduced levels of endogenous hormones in both males and females, to gonadal histopathologies and intersex (presence of ovotestes) fish. Overt endocrine disruption in fish does not appear to be a ubiquitous environmental phenomenon, but rather more likely to occur near sewage treatment plants, pulp and paper mills, and in areas of high organic chemical contamination. However, more wide-spread endocrine disruption can occur in rivers with smaller flows and correspondingly large or numerous wastewater inputs. Some of the most severe examples of endocrine disruption in fish have been found adjacent to sewage treatment plants. Effects are thought to be caused prima-rily by natural and synthetic estrogens and to a lesser extent by the degradation products of alkylphenol poly-ethoxylate surfactants. Effects found in fish near pulp and paper mills include reduced levels of estrogens and androgens as well as masculinization of females, and has been linked to the presence of β-sitosterol, a plant sterol. Effects seen in areas of heavy industrial activity typically include depressed levels of estrogens and androgens as well as reduced gonadal growth, and may be linked to the presence of PAHs, PCBs, and possibly dioxins. At this time, however, there is no clear indication that large populations of fish are being seriously impacted as a result of endocrine disruption, although additional work is needed to address this possibility. (PDF contains 63 pages)

Coral Disease and Health Workshop: Coral Histopathology II

The health and continued existence of coral reef ecosystems are threatened by an increasing array of environmental and anthropogenic impacts. Coral disease is one of the prominent causes of increased mortality among reefs globally, particularly in the Caribbean. Although over 40 different coral diseases and syndromes have been reported worldwide, only a few etiological agents have been confirmed; most pathogens remain unknown and the dynamics of disease transmission, pathogenicity and mortality are not understood. Causal relationships have been documented for only a few of the coral diseases, while new syndromes continue to emerge. Extensive field observations by coral biologists have provided substantial documentation of a plethora of new pathologies, but our understanding, however, has been limited to descriptions of gross lesions with names reflecting these observations (e.g., black band, white band, dark spot). To determine etiology, we must equip coral diseases scientists with basic biomedical knowledge and specialized training in areas such as histology, cell biology and pathology. Only through combining descriptive science with mechanistic science and employing the synthesis epizootiology provides will we be able to gain insight into causation and become equipped to handle the pending crisis. One of the critical challenges faced by coral disease researchers is to establish a framework to systematically study coral pathologies drawing from the field of diagnostic medicine and pathology and using generally accepted nomenclature. This process began in April 2004, with a workshop titled Coral Disease and Health Workshop: Developing Diagnostic Criteria co-convened by the Coral Disease and Health Consortium (CDHC), a working group organized under the auspices of the U.S. Coral Reef Task Force, and the International Registry for Coral Pathology (IRCP). The workshop was hosted by the U.S. Geological Survey, National Wildlife Health Center (NWHC) in Madison, Wisconsin and was focused on gross morphology and disease signs observed in the field. A resounding recommendation from the histopathologists participating in the workshop was the urgent need to develop diagnostic criteria that are suitable to move from gross observations to morphological diagnoses based on evaluation of microscopic anatomy. (PDF contains 92 pages)

Control of Disease in Aquaculture: Proceedings of the Nineteenth U.S.-Japan Meeting on Aquaculture, Ise, Mie Prefecture, Japan, 29-30 October 1990, Satellite Symposium: 2 November

The United States and Japanese counterpart panels on aquaculture were formed in 1969 under the United States-Japan Cooperative Program in Natural Resources (UJNR). The panels currently include specialists drawn from the federal departments most concerned with aquaculture. Charged with exploring and developing bilateral cooperation, the panels have focused their efforts on exchanging information related to aquaculture which could be of benefit to both countries. The UJNR was begun during the Third Cabinet-Level Meeting of the Joint United States-Japan Committee on Trade and Economic Affairs in January 1964, In addition to aquaculture, current subjects in the program include desalination of seawater, toxic microorganisms, air pollution, energy, forage crops, national park management, mycoplasmosis, wind and seismic effects, protein resources, forestry, and several joint panels and committees in marine resources research, development, and utilization. Accomplishments include increased communication and cooperation among technical specialists; exchanges of information, data, and research findings; annual meetings of the panels, a policy-coordinative body; administrative staff meetings; exchanges of equipment, materials, and samples; several major technical conferences; and beneficial effects on international relations. (PDF file contains 150 pages.)

Control of bacterial disease in small scale fresh-water aquaculture: Project R0754. Project completion report December 1998 - May 1999

The work presented here represents an 18-month study to examine the relationship between environmental conditions, bacterial load in the water and bacteria levels in tissue macrophages of a range of clinically healthy freshwater fish species, farmed in a range of culture systems in Thailand and Vietnam. Preliminary assessment was made of the clinical significance of the macrophage bacterial load. The aim of this work was to improve production in fresh-water aquaculture through the control of clinical bacterial disease and subclinical infection, and to identify management practices most effective in promoting fish health. [PDF contains 37 pages]

Factors affecting the susceptibility of salmonid fish to disease

A review article discussing the degree of susceptibility of fish to outbreaks of disease and whether, besides from changes in the physical and chemical characteristics of the environment, this susceptibility is instrumental in determining whether or not pathogenic challenge results in disease. The article summarises a decade of work on this subject at the Windermere laboratory of the Freshwater Biological Association and suggests possible directions for future research. The article covers experimental design, effects of environmental stress (including discussion on the hypothalamic-pituitary-interrenal (HPI) axis in salmonid fish), sexual maturation, research areas for future development and evolutionary considerations. There are a number of accompanying figures and images.

Combating fish disease. An explanation of the controls on notifiable fish diseases in Great Britain and advice on steps to prevent the spread of disease

For many years action has been taken to prevent the introduction and spread of serious fish diseases in Great Britain. In 1993 national rules were replaced by European Union wide rules designed to promote trade within the single market while safeguarding those parts of the Union with a high fish health status - such as this country. This booklet details the checks and controls which are applied to prevent the spread of disease outbreaks in this country. One can see that different rules apply to different diseases, generally reflecting the severity and other characteristics of the disease. The booklet also tries to explain the diseases and helps to recognise symptoms. This booklet is split into three parts: Part 1 gives an overview of the controls; Part 2 gives details for each of the diseases; and Part 3 gives advice on some of the precautions you can take to guard against the spread of disease.