![]() ![]() The guppy is also famous in the world of science. The name was later changed when it was discovered that the same species had already been described from Venezuela, but the ‘guppy’ part stuck. Robert John Lechmere Guppy was an avid naturalist, and in 1866 sent samples of these pretty little fish to the British Museum in London where the species was initially named after him: Girardinus guppii. Many do not realise that the guppy, now world-famous in the aquarium trade and as a mosquito control agent, is named after a Trinidadian. Therefore, one chance colonisation above a waterfall can lead to a permanent population. As well as being prolific breeders they also mature extremely quickly, completing as many as 3-4 generations in a single year. Even from the river bank it is possible to watch males perform their distinctive ‘sigmoid’ courtship dance, which involves arching into an s-shape, raising their dorsal fin and intensifying their colouration in an attempt to seduce a female.Īlthough they are not quite as adept at scaling waterfalls, their special trick is that once a single female guppy manages to find herself in a new stream or pool, she can colonise it single-handedly by using stored sperm to produce vast numbers of live babies in a matter of weeks. Males are smaller and display vivid patches of orange, green and yellow, while the larger females are plain. Like the jumping guabine, these tiny (2-3cm) fish are also found almost everywhere in both Trinidad and Tobago and are usually seen in shoaling in large numbers in shallow water. Photo courtesy Amy DeaconĪ second species that has managed to breach at least some of the barriers and make its home in the Main Ridge streams is the Guppy or Millions-fish, Poecilia reticulata. Jumping guabine can travel for some distance on land and even up waterfalls. While in the water, they are ravenous predators of aquatic invertebrates, small fish and tadpoles. Incredibly, they have been recorded jumping as high as 14cm, more than their total body length, to catch prey on overhanging vegetation or at the water’s edge. ![]() Travelling outside of water is also the reason that they are often the only fish found in the highest stretches of rivers in both the Main Ridge and the Northern Range: Jumping guabine can simply make multiple jumps to scale the sheer rock face of a waterfall! Another advantage of jumping is that it allows hungry individuals to hunt prey, such as ants, that may be otherwise out of reach. This allows it to travel short distances over land to new bodies of water, and it is not unusual to find a few individuals in isolated puddles, often some distance from permanent water. As such, it can ‘jump’ out of water onto land and survive for a considerable time, as long as it does not dry out entirely. The ability to beach yourself may not seem like much of an evolutionary advantage, but the jumping guabine has another trick up its sleeve– it can breathe atmospheric air through its tail, which is covered in capillaries. As the name suggests, this fish has the ability to launch itself completely out of the water. However, the Main Ridge individuals are decidedly larger, as with fewer fish predators around they live longer. ![]() Ordinarily, this species reaches around 10cm from head to tail. Without a doubt, the king of the Main Ridge rivers is the Jumping Guabine, Aneblepsoides hartii. Typical aquatic habitat in the upper reaches of the Main Ridge Reserve. Only the most intrepid make it through to dominate the uplands. Most fish will never manage to traverse these barriers, forever restricted to the lowland rivers. Often these are tens of metres high, much like those at Argyll. In North East Tobago, fish in the lower reaches moving upstream soon reach one of many waterfall barriers at the edge of the Ridge. While we humans can easily drive along the Roxborough – Parlatuvier road to access the reserve, fish must initially colonise inland from the sea. Thirteen species of freshwater fish have been recorded in Tobago, but only a handful of these have successfully conquered the Main Ridge. This time, we dip our nets into the cool, glistening streams that run through the reserve and see what we might catch! This feature was first published in the Tobago Newsday on March 16, 2017. In this week’s column Amy Deacon, Lecturer in the Department of Life Sciences at The University of the West Indies, St Augustine and Secretary of the Trinidad and Tobago Field Naturalists’ Club, returns to the Main Ridge. ![]()
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