Lionfish - A problematic invasive species that might have escaped from an aquarium in Florida to breed amd wreck havoc in the caribbean.

A paper has recently been published by Gordon Copp, Lorenzo Vilizzi, and Rodolphe Gozlan in the journal Aquatic Conservation: Marine and Freshwater Ecosystems which eludes to the fact that the higher the population density in England, the more likely the natural ecosystems can be tainted with pet fish.

This is not a new piece of information. It has been known for quite some time that the ecosystems which are closer to roads, fish markets and pet shops are more likely to be subjected to pet fish than those which are not close to these avenues.

The object of the study was to perform a statistical analysis to take a look at the spacial relationships between pet fish contamination and the demographics which led to these fish being released into the wild, and also to test whether or not these demographic factors are a reliable way of estimating how many alien species are introduced into these ecosystems.

The case study was carried out using an intermediate scale for all of England, dividing the country into 1500 squares of 10 square kilometers each.

The study consisted of the following data sets to be used in their analysis: non-native fresh water fish occurrences in the wild; the numbers of non-native fish imported, and demographic information such as: numbers of humans, pet shops, garden centers and fish farms per unit area.

The study found that the incidences of pet fish contamination directly co-related to the density of the human population.

If you would like to learn more check out the paper: Copp, GH, L Vilizzi and RE Gozlan (2010) The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in England. Aquatic Conservation: Marine and Freshwater Ecosystems 20, pp. 595–601.

“Small fish may have small brains but they still have some surprising cognitive abilities”, says Dr Jeremy Kendal* from Durham University’s Anthropology Department.

Dr Kendal is the lead author of a new study showing that Nine-spined stickleback fish (Pungitius pungitius) can compare the behaviour of other sticklebacks with their own experience and make choices that lead to better food supplies.

“‘Hill-climbing’ strategies are widely seen in human society whereby advances in technology are down to people choosing the best technique through social learning and improving on it, resulting in cumulative culture”, says Dr Kendal. “But our results suggest brain size isn’t everything when it comes to the capacity for social learning.”

Around 270 Nine-spined sticklebacks were caught from Melton Brook in Leicester using dip nets. After being divided into three experimental groups and one control group, the fish were housed in different aquariums and the fish in the experimental groups were subjected to two different learning experiences and two preference tests in a tank with a feeder placed at each end.

1.) The fish were free to investigate both feeders during a number of training trials. One feeder (dubbed “rich feeder”) always handed out more worms than the other one (dubbed “poor feeder”). The fish were then tested to see which feeder they preferred.
2.) In the second training trail, those fish that come to prefer the rich feeder could see other fish feeding. During this stage, the rich and poor feeders were swapped around and the rich feeder either gave even more worms than before or roughly the same or less. During the second test, the fish were once again free to explore the tank and both feeders. Around 75 per cent of the Nine-spined sticklebacks had learned from watching the other fish that the rich feeder, previously experienced first hand themselves as the poor feeder, gave them more worms. In comparison, significantly fewer sticklebacks favoured the feeder that appeared to be rich from watching other sticklebacks if they themselves had experience that the alternative feeder would hand out roughly the same or more worms.

Further testing showed that the sticklebacks were more likely to copy the behaviour of fast feeding fish.

“Lots of animals observe more experienced peers and that way gain foraging skills, develop
food preferences, and learn how to evade predators”, Dr Kendal explained. “But it is not always a recipe for success to simply copy someone. Animals are often better off being selective about when and who they copy. These fish are obviously not at all closely related to humans, yet they have this human ability to only copy when the pay off is better than their own.”

The study, which has been published in the journal Behavioral Ecology, was carried out by scientists from St Andrews and Durham universities and funded by the Biotechnology and Biological Sciences Research Council. The lead author of the study, Dr Kendal, is a Research Council UK Fellow.

Just like dolphins, sharks can be trained to roll over to be cuddled by humans. In experiments carried out in the United States, several species of shark allowed themselves to be picked up from the water and cuddled by their trainers.

The U.S. trainers used coloured boards and sounds to train their sharks to respond to commands. No one had attempted to train sharks in this way before and the results are truly ground breaking. Shark keepers now hope that the new technique will give sharks a higher quality of life in captivity. When sharks ned to be moved, the normal practise is to chase them around, but a trained shark could instead be thought to just gently swim to a certain spot.

“The US team has shown that many varieties of sharks can quickly learn to respond to a combination of audible and visual signals”, says Carey Duckhouse of UK’s Sea Life Centres.

Keepers at the UK’s Sea Life Centres are planning to use the methods developed in the U.S. to train sharks kept in British facilities. Colour boards and sounds will be used to show each shark when it is his or her turn to receive food. If everything goes according to plan, the fastest learners in the shark tanks will grasp the idea within three months.

When a shark have learned to associate particular colours and sounds with food, the signals will make it approach its keeper who will be holding a “target stick” against which the shark will rub its nose in hope of getting a tasty treat.

”Some species, such as zebra sharks, will even roll over to have their tummies scratched or allow themselves to be lifted from the water without any kind of struggle,” says Dickhouse.

“Every single spot of the ocean along the West Coast is affected by 10 to 15 different human activities annually”, says Ben Halpern, a marine ecologist at the National Center for Ecological Analysis and Synthesis (NCEAS) at the University of California at Santa Barbara.

In a two-year long study, Halpern and his colleagues have documented the way humans are affecting the ocean off the West Coast of the United States. The research team has overlaid data on the location and intensity of 25 human derived sources of ecological stress, including commercial and recreational fishing, land-based sources of pollution, and climate change. The information has been used to construct a composite map of the status of West Coast marine ecosystems.

“We found two remarkable and unexpected results in this research,” says Halpern. “Ocean management needs to move beyond single-sector management and towards comprehensive

ecosystem-based management if it is to be effective at protecting and sustaining ocean health. Also, the global** results for this region were highly correlated with the regional results, suggesting that the global results can provide valuable guidance for regional efforts around the world.”

The study results show that hotspots of cumulative impact are located in coastal areas close to urban centres and heavily polluted watersheds.

“This important analysis of the geography and magnitude of land-based stressors should help focus attention on the hot-spots where coordinated management of land and ocean activities is needed,” said Phillip Taylor, section head in NSF’s* Division of Ocean Sciences.

You can find more information in the article from the research team published in the journal Conservation Letters on May 11. The project was conducted at NCEAS, which is primarily funded by NSF’s Division of Environmental Biology.

* National Science Foundation (NSF)

** The lead scientists on the U.S. study have already carried out a similar analysis on a global scale; the results were published last year in Science.