Adventure Ausrama Blog

As international trade continues so does "equalization" of the planet. Many marine species are now found in all waters of the world. This is because transport ships literally hoover up animals in ballast water, which is released at any time, any place, when it is no longer needed. All ballast water is released into a port when cargo is taken onboard. Marine survivors of this rough treatment give the local environment a go. Some are successful and multiply to epidemic proportions. Zebra mussels and Pacific seastars in particular are a major problem. An Australian study gathered data such as ports where ballast was likely to be taken on and where it would probably be released. Marine species spread this way were identified and it was predicted how long they would survive. This data was fed into a computer. It was noticed that shipping volume was increasing mainly in the transport of primary products. Most of this Australian export was delivered to Asia and

Mussel sperm have to find the right egg. This is not as easy as it seems. When the eggs are released they can be scattered through ocean water or river. While mussels are attached to rocks, eggs and sperm are at the mercy of the elements. The eggs have to let sperm know that the eggs are available, so they send out a chemical message to attract suitable sperm. Many species release chemical signals. The message sent has to be differentiated to prevent fertilization by siblings. A test was done forcing sperm to fertilize chosen eggs. Only compatible matches gave healthy offspring. In a later test mussel sperm were observed to choose compatible eggs to produce health young. This is the first time chemical attraction has been observed in mussels. It shows how important compatibility is in many species. This brings into question the theory of gene pools where there is deemed to be no barrier to gene pairing. The idea that any male and female can have offspring no longer stan