The release of sediment and algae-boosting fertilizers into Lake Victoria can cause cichlid species to interbreed in the murky water, according to Ole Seehausen, evolutionary biologist at the University of Bern in Switzerland and the Swiss Federal Institute of Aquatic Science and Technology in Kastanienbaum.

In a recent article published in Nature, Seehausen and his colleagues are shedding some light on the question of how closely related species of cichlids living adjacent to each other in Lake Victoria manages to avoid interbreeding. According to Seehausen et al, species may develop and stay distinct because of how the members of each species see colours.

Seehausen and his research team have studied closely related species of Lake Victoria cichlids where the males are either blue or red. It has since long been known that females of these species prefer to mate with the male displaying the brightest colours, but the new research suggests that both sexes have evolved to preferentially see only red or blue. This means that if a brightly coloured red male swims by a blue-seeing female, she will not be able to appreciate his sexy brightness since see can not see the colour red.

“Reds and blues live in the exact same spot,” says Seehausen,. “Colour is very important in mate choice.”

In order to fully understand the role of vision in underwater evolution, we must be aware of how light acts when it penetrates the water. Blue colours shine much brighter than red ones in the shallows, while red pigmentation trumps blue as we proceed farther down. As you probably have guessed already, red cichlid species tend to be found near the surface in Lake Victoria, while the blue ones inhabit greater depths.

To learn more about what happens to cichlids in the transition between red and blue zones in the lake, Seehausen and his team studied species inhabiting the shores of five different islands. The cloudiness of the surrounding waters varies from island to island due to variations in sedimentation, giving the researchers a great opportunity to study the effects of varying water clearness.

In comparatively clear waters, the colour that appears brighter slowly and gradually changes from red to blue with depth. This makes each species stay within its own zone and prevents interbreeding. In more clouded waters, the change from red to blue occurs much more suddenly, causing a higher prevalence of interbreeding between closely related species of fish.

Further testing in laboratory aquariums showed that hybrid females, like the ones living in cloudy waters, did not favour red males over blue ones or the other way around. This distinguished them from non-hybrid females, since females belonging to a species with red-sensing eyes picked red males in the laboratory tanks while the blue-sensing females opted for blue beaus.

Seehausen is now worried that the unchecked release of sediment and algae-promoting fertilizers into Lake Victoria will cause more and more fish to interbreed, thereby greatly reducing the number of species in a lake famous for its astonishing biological diversity and degree of endemic species. “Species diversity in this lake has imploded in the last 30 years,” Seehausen says. “It is the largest human-witnessed mass extinction of vertebrates.“

You can read more in the article “Speciation through sensory drive in cichlid fish” by Seehausen et al. http://www.nature.com/nature/journal/v455/n7213/abs/nature07285.html

New animal cruelty laws in Switzerland deem recreational fishing as animal cruelty.

The law ban catch and release fishing as the authorities have found that this fishing technique is morally wrong as it in facts is the practice of torturing animals for fun. You will however still be able to fish if you kill and/or eat the fish you catch as this is not consider recreational fishing as it has another purpose than just your enjoyment. The new law also outlaws using live fish as bait. It does not appear to regulate other types of live bait items.

This new laws make the Swiss fishing laws some of the most strict / if not the strictest, in the world today.

Switzerland has adopted new strict animal cruelty laws. The new law contains more strict rules regulating how to keep most pets and domestic animal. An example is that many animals such as hamsters, lamas, alpacas and sheep no longer can be kept alone. They need to have visual contact with other specimens of the same species. Another example is that people who want to buy their first dog have to go to compulsory classes for “want to be dog owners” before they can legally buy a dog. The law details how all domestic animals should be kept regardless of whether they are kept as pet, for scientific research or in zoos.

I will not go into depth about exactly what this new rule stipulates but I will say a few words relating to fish keeping (If you live in Switzerland and want to know more about I recommend reading the original law text or contact a local authority).

The law bans the flushing live fish. You need to kill the fish before you can legally flush it. The law does not state exactly how the fish should be killed before being flushed.

Starting September 2008 Switzerland legislation is going to be enforcing some new guidelines to for fish owners.  Aquariums will no longer be allowed to be transparent on all sides, and any fish over 20cm will have to be housed in a tank/pond that meets the size restrictions that will be put into place. The new legislation also speaks of the importance of proper maintenance, and water quality, temperature, oxygen levels and salinity should be correct for the individual species being cared for.

Social Fish, to include goldfish, will no longer be able to be kept in a solitary habitat, but will require at least one friend. Forget about freezing your fishy friend or flushing it down the loo. From now on fish keepers will be required to stun the fish before killing it, using a non-prescription narcotic available to the general public.

To read this article in its entirety and see how the new legislation will effect anglers throughout Switzerland visit: http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=1671