Thirteen species of freshwater fish have been recorded in Tobago, but only a handful of these have successfully conquered the Main Ridge. While we humans can easily drive along the Roxborough – Parlatuvier road to access the reserve, fish must initially colonise inland from the sea. In North East Tobago, fish in the lower reaches moving upstream soon reach one of many waterfall barriers at the edge of the Ridge. Often these are tens of metres high, much like those at Argyll. Most fish will never manage to traverse these barriers, forever restricted to the lowland rivers. Only the most intrepid make it through to dominate the uplands.
Without a doubt, the king of the Main Ridge rivers is the Jumping Guabine, Aneblepsoides hartii. Ordinarily, this species reaches around 10cm from head to tail. However, the Main Ridge individuals are decidedly larger, as with fewer fish predators they can live longer.
This piece originally appeared in the Tobago Newsday on March 16th 2017.
Trinidad & Tobago’s rivers are filled with at more than 40 different species of fish of all shapes, sizes and habits. One of the best-known is the ‘teta’, also called the ‘Anne Marie’, and known to scientists as Hypostomus robinii.
This article originally appeared in the T&T Newsday as part of the TTFNC's natural history series.
Most of us associate crabs with a trip to the beach – scuttling across the sand or hiding in a rockpool. However, here in T&T, these ten-legged crustaceans have even colonised the upper reaches of our forest streams. The mountain, or manicou, crab (Rodriguezus garmanii – formerly placed in the genus Eudaniela) is typically found at between 50-800 metres elevation, and displays several impressive adaptations that allow it enjoy an inland existence.
This article originally appeared in the Newsday as part of the TTFNC's natural history series.
The rivers of Trinidad are home to six very distinctive types of catfish. These include armoured catfish such as the leopard-spotted ‘teta’ (Hypostomus robinii), the enigmatic ‘cascadu’ (Hoplosternum littorale) and the popular aquarium fish ‘pui pui’ (Corydoras aeneus). All tend to be bottom-dwellers and are grouped together as ‘cat’ fish on account of their barbels, which are sensory ‘whisker-like’ structures on their faces used to locate food. In Trinidad the fish most commonly referred to by the name ‘catfish’ is Rhamdia quelen, which unlike the species listed above, is silvery, unarmoured and scale-less.
Rhamdia is found throughout much of Central and South America, from Mexico to Argentina. In T&T, it is especially common in the rivers of the southern slopes of the Northern Range, but is found throughout the country, with the exception of Trinidad’s north coast and the whole of Tobago.
Like many catfish species, Rhamdia possess mildly venomous spiny rays on their pectoral and dorsal fins, which are used for defence against larger predatory fish. The barbels on either side of their face help them locate food in dark or murky waters, such as their preferred prey of small fish. However, their varied omnivorous diet also includes insects, zooplankton, plant matter and crustaceans.
This feature originally appeared as part of the TTFNC's weekly natural history series in the national 'Newsday' paper.
If you are lucky enough to have spent any time as a child catching fish in ditches and streams, you have almost certainly encountered this particular species. It is known by several names, including the formal scientific name of Anablepsoides hartii (formerly Rivulus hartii), Hart’s rivulus, and ‘seven colours’. However, most people probably know it as the ‘jumping guabine’.
At full size, these small fish are around 10cm and although dull from a distance, they have vivid horizontal coloured stripes stretching along their body. Males and females can be distinguished fairly easily by their colouration; males tend to be brighter and have distinctive pale orange edges to the tail, while the female’s tail has a darkened tip (see photo below).
Jumping guabines are found throughout T&T as well as in northern Venezuela. They thrive in a variety of habitats, from muddy road-side puddles to the shallow edges of large rivers.
We are now entering the final year of the 5-year biodiversity project out here in Trinidad.
To mark this milestone, I have begun writing a blog for the BioTIME website, which will be updated regularly to document fieldwork adventures over these last months.
I hope to offer insights into what it's like doing fieldwork here on a day-to-day basis, and from time to time it will also feature species' profiles of some of the most interesting inhabitants of the Northern Range streams...
You can visit the blog here.
I enjoy writing about natural history, science and other interesting things. Links to some of these pieces are posted here.