Tuesday, February 03, 2004

The second sampling fieldtrip

The second sampling fieldtrip was scheduled On 2feb2004. Despite the drizzling rain, we went to Sungai Buloh from 2pm to 5pm. As we were able to get Prof. Peter Ng and another experienced shrimps taxonomist, Mr. Cai Yixiong to come along, we aimed to find the all six species of mangrove shrimps previously found from Sungai Buloh.

At the beginning, we focused on finding the less common small prawns species, these included: Potamalpheops tigger, Potamalpheops johnsoni and Athanas Polymorphus. As recent studies reported that the Potamalpheops spp. and Athanas polymorphus were found at shallow water pools under roting log, we tried to look for these type of microhabitat, turned over the log and look for the prawns. However, as the luck was not with us, after trying for almost 3 hours, we only managed to get a juvenile Alpheus spp. and 2 small prawns, either Potamalpheops spp. or Athanas spp. The prawns were kept alive in plastic container filled with seawater.

On a second note, there were quite a lot of juvenile marine prawns observed from the study site. These marine prawns included Penaeide prawns, Macrobrachium spp. and Palemon spp. As mangroves have been always the nursery area for marine prawns, these juvenile marine prawns found in mangrove were just 'visitors' rather than 'residents' of mangroves. However, these juvenile prawns were similar to the true small mangrove prawns in terms of size (both about 1-1.5 cm in length), they can be differentiated at field by observing the color, body shape, rostrum and the eyes morphology.

Equipment used for this sampling included: small hand net, clear plastic containers or ziplock bags (filled with clear seawater, enable to differentiate to genus level of the shrimps) and some Nalgene bottles with 75% alcohol (to kill and preserve the prawns).