The increase of disease in our ocean

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The increase of disease in our oceans. Case
study the Pilchards Sardinops sagax of the
Southern Oceans of Australia.
Andrew G Challingsworth Ph0439962581aquanet-
place_at_hotmail.com www.aquanetplace.com.au,
Deakin University.
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Abstract

• A literature review was conducted of Scientific
  journals.
• To accurately assess the scientific information,
  on the increase of disease in our oceans.
• We can now accurately generalize that disease
  outbreaks in marine organism have increased in
  recent years.
• Disease outbreaks correspond to a list of
• environmental factors.
• Case study the Australian pilchard Sardinops
  sagax and how changing environmental factors
  resulted in a disease epidemic.

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Introduction

• After reviewing the scientific literature.
• We can accurately assess, that disease is more
  prominent in the ocean environment.
• Environmental factors are increasing disease
  episodes in our oceans.
• Environmental change can interact with disease in
  our oceans in many ways. (Lafferty, Porter Ford
  2004).

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• The aquatic environment needs to be thoroughly
• understood.
• Growth and reproduction of fishes is affected
  when the environmental parameters of aquatic
  environments diverge beyond acceptable limits.
• This may lead to acute or chronic disease
  conditions. (De Silva et al 2003,Topic one).

Australian Pilchard Sardinops sagax,
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Methods

• An accurate study of our environmental factors
  needs to be established.
• Environmental factors
• Physical factors i.e. Temperature, Light,
  Dissolved Gases.
• Anthropomorphic influences/factors i.e.
  Pollution from factories, Sewage.
• Biological factors i.e. Microorganisms,
  Dinoflagelates, Blue green algae.

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• A biopsy of the Biology of the Australian
  Pilchard Sardinops sagax.
• A biopsy of the disease epidemic (PHV) Pilchard
  Herpes Virus.

Dead pilchards on a beach in Western
Australia during the mortality event in 1998.
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Results

• Environmental factors
• Physical factors
• Temperature thermal tolerance limits, optimum
  required. (De Silva et al 2003,Topic one).
• Affects resistance to disease.

Red coral, tolerance limits to temperature change,
Climate warming.
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• Light
• Increasing light levels.
• Growth in unicellular algae.
• Result of climate change.

A
B
A Increase in harmful algal blooms 1970-1990
Climate change. (Lafferty, Porter Ford
2004). B Dinoflagellate.
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• Temperature changes solubility of toxic compounds
  i.e. crude oil, pesticides.

• Crude Oil Toxicants increase susceptibility to
  disease by impairing defenses i.e. mucus
  production. (Lafferty, Porter Ford 2004).

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• Heavy metals also become more toxic.
• (De Silva et al 2003,Topic one).

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• Physical factors affecting the aquatic
  environment
• Light
• Light and the effects of climate change with
  increasing temperature and light levels can cause
  growth in unicellular algae.
• There has been a notable increase in harmful
  algal blooms between the periods of 1970-1990
  corresponding to climate change. (Lafferty,
  Porter Ford 2004).

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Physical factors

• Dissolved Gases
• Excess Carbon dioxide dissolved in water can
  depress fish respiration. Global factors include
  predicted rise in oceanic carbon dioxide
  concentrations. (Lafferty, Porter Ford 2004).

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Environmental factors

• Anthropomorphic influences
• Pollution from factories
• Heavy metals
• In Australia Mercury and Cadmium are contaminants
  of fish.

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Anthropomorphic influences

• Non-Metals
• Biodegradation resistant organochlorine compounds
  are toxic to fish.
• Can become concentrated in the food chain DDT and
  dieldrin as they are highly resistant to
  degradation.
• Sewage
• Discharge reduces water quality causes oxygen
  depletion caused by microbial growth.
• Nitrates and phosphates may stimulate excessive
  algal blooms and leads to oxygen depletion.