420 Dive Log Australasia OCTOBER 2026

ENVIRONMENTAL PRESSURE Survival from challenges of life varies a great deal amongst individuals. To survive, you need to be able to find food and water, avoid being eaten and to find shelter and warmth to name a few challenges. In times of starvation and disease, some people are susceptible to disease and others survive. Many people survived exposure to COVID 19, some did not. In the greatest pandemic of all in England in 1347 and 1348, up to half of the population of towns and cities died from the Black Plague. Why did some people survive? They had an immunity of sorts that enabled their bodies to combat the deadly bacteria until their health was restored. In the ocean, all lifeforms have to deal with problems relating to infection and sanitation. This is extremely important in all marine life . The photo below shows a Cleaner Cling Goby tending to the eggs of a Weedy Sea Dragon. Eggs can be fouled by algae, hydroids and all sorts of marine parasites that try to use the eggs as a food source or an anchor. All life forms are under continual attack every day from a host of pathogens, parasites and they must find ways to overcome them or they may die. In this case, a mutualistic arrangement has developed between the tiny Cling Goby and the Weedy Sea Dragon. The goby gets food and the

Weedy ‘s eggs are cleaned of ecto-parasites. Salinity is another aspect of environmental pressure. Humans will go mad and die of we Female Sea Horses send out powerful pheromones to alert males that she is fertile and wishes to mate. If she cannot find a mate, the species is endangered.

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Dive Log Australasia #420 October ’26

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