How do marine aquarium species colonise reefs.

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How do marine aquarium species colonise reefs.

Post  liquidg on 14th December 2013, 2:12 am

Many marine life forms give birth to live young and corals may expel eggs and sperm to mix in the ocean and find each other in the waters by accident.

Some species may lay their eggs upon a solid surface and the male will swim over these adding his sperm to these eggs.

Other species may lay already fertilised eggs onto a surface or directly into the surrounding waters.

Others may give birth to larvae or juveniles to live at their planktonic stage for quite some time.

For basically all marine aquarium species of fish and inverts and most other marine life, these as juveniles or fertilised or as unfertilised eggs, float to near the surface or make their way to near the oceans surface to feed on and live with the oceans predominant phyto-planktonic life, of which they are for a while, that being planktonic sized as well.

During this time of being planktonic most all of these are virtually transparent, whether its lobsters, angelfish to cod to marlin, the start of life is similar!

Dispersal.
The most abundant breeding potential is throughout the tropical waters of the world, which is within close proximity to the equator, maybe a thousand klms north and south †and in shallow waters.
This area has a breeding cycle that is perpetual (, unlike most southern species that breed for the summer), this is the reason the pristine areas of our far north have so much life and so much to give to the entire east coast of Australia.
Around the world the ocean currents vary, some run seasonally, some run constantly, some in surges.
Our east ausy current, runs most of the year with lager surges, which happens as the sun heads towards our side of the equator
We have four main surges and most are assisted by eddies that spiral pulling high nutrient deeper waters to the surface enabling an abundant food supply for the plankton that feeds the now planktonic sized aquarium life forms.
These current surges start towards the warmer months and ease off around the end of the warmer months, but are still part of the east ausy current.
There are two surges from the south to north that helps bring cooler water species north while in their planktonic stages.
These happen firstly in June and then around September, they normally only last for a max of two weeks.


Signals to breed and how to disperse the off spring.
The oceans cycle of life happens as a result of temperature, moon cycle, tides or currents.
One or all of these set off instinctive switches within our ocean creatures compelling them to breed.
Almost all the oceanís inhabitants release eggs or sperm or larvae into the surrounding waters.
Some intentionally carry out this action to moonlight, darkness or a specific current or condition.

All this is designed to give their offspring the best chance of survival.
Once a creature releases their eggs, sperm, larvae etc, (or for some creatures, they have live young or hatch from eggs attached to a rocky surface) they are at the mercy of the oceanís currents,swells and surges.
At this stage, most have a tiny bubble or use their swim bladder to keep them near the surface to be apart of and feed on the plankton.
This process can go on for days or weeks as they grow and are carried along by our east Aussie current.
From birth or release to the time that they are too big or leaving their transparent stage, they may be carried 20kms or they may travel 2 thousand klms, it depends on many things as to where they reach the stage where they need to head for the floor of the ocean or find any shelter as predators may soon be able to see them.

From this stage, the massive kill off begins.
The tiny amount of reef areas compared to sandy bottoms, massive depths, estuaries and they are also washed up on beaches and eaten by filter feeders like whales, corals, anemones, clams etc, all these claim massive numbers.
Also when carried too far south, the winter kills all tropical species.
Combine predators as they grow, territorial fights and water quality changes, you are left with what we see, only one percent, that is what is left for us to affect.

A miniscule amount reach adult hood of countless billions produced in our seasonal tropics.
This is unlike either side of the equator, where the oceans cycle of life is perpetual.

There are several ways that the different creatures produce offspring in the ocean, some give birth to live young, then a few mouth breed and pouch brood, and then there are some that lay eggs, then you have others that sense sperm or egg release as a signal to release. Then you have inverts like most anemones, tube worms, corals etc that divide and release eggs or sperm as well, this gives them more chances of perpetuating their species.

Over all, it is a very complex and tough beginning for all the creatures that make up the oceans cycle of life.

Temperate species.
In the cooler waters the breeding is seasonal as the young need the warmer temperatures to grow and attain some size for survival.
The colours on average of the cooler species is darker, more dull, as they do not need to blend in with tropical invert colours and other factors can affect them, planktonic food types which are more phytoplankton rich in cooler waters.
Most of the life that comes past in the stronger currents doesnít make it to the shoreline reefs unless something happens to push them in.
Once in the early eighties and then again in the mid nineties, we had mini cyclones or what could be compared to cycolic winds come in close to Stradbroke Island then the gold coast, both times several angel fish species were predominant in the plankton. With these species ready to drop from the plankton, the very strong winds literally bent the surface part of the current in towards shore.
In these years from late February on when the juveniles were big enough to see, we found enormous amounts of semicirculatus, imperators, bi colours, and coral beauties all in massive numbers.
So the next time we have a big blow in either October and November, expect a lot of aquarium species to saturate the coastline.

Sexual and A-sexual breeding
Some species, for instance, like the damselfish, which includes clown fish, lay their eggs onto a hard surface to be fertilized and await birth.
These fish have an instinctive function as they are moved along by the current to sense when near an anemone,high CO2 levels cnacel this function out.
Shrimps and lobsters flip there tail when their young have developed enough until they are all gone, then shed their shell releasing hormones to attract a male to do his bit before her shell goes hard.
Sometimes we find many males waiting for the big moment, some shrimp have a partner to do this.
Angelfish, male and female do a little dance normally up off the bottom then, release eggs and sperm to make contact, most wrasse while school normally, release sperm and eggs to make contact, some species have partners.
Corals, feather stars and tubeworms release their eggs and sperm to find each other, although tubeworms will detect a release from the opposite sex for them to release as well.
Most of the creatures in the ocean release the young or eggs to swim or float with in †the plankton rich currents to be carried along until they sense a reef via reef sounds like waves/clicking of crabs as such,or too big to be there, then the recently placed log, rock formation or sunken ship, that was near void of life, gradually becomes abundant with the oceans cycle of life.

This map is of the east Auzy current as summer intensifyís it, dispersing marine life at their planktonic stages along the east Australian coast from September through to December, at its strongest.

*. Represents the flow of the east Australian current.

E. Represents example of eddies.

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Queensland ocean currents and temperature of those currents and further marine conditions.

These pics will give you an insight into how the currents and ocean temperatures change over time and at what time of year.
September 2012
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October 2012
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November 2012
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December 2012
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January 2013
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