The North Rupununi region of southwestern Guyana, South America, is sparsely populated with small settlements and Amerindian communities over vast areas of rainforests and savannah. The Amerindian communities are small villages of 200 to 1000 people who rely mainly on subsistence farming and fishing. A few of the settlements are old cattle ranches that have transitioned into ecolodges and tourism in the North Rupununi is growing rapidly. A Catch and Release Sport Fishing Program (USAID/CARANA) was started to help establish an alternative and sustainable business for these communities. The project has continued with funding from Compete Caribbean (IDB) to establish a workable management plan specifically for Arapaima that allows continued traditional harvesting of these fish as well as catch and release sport fishing.
Arapaima are among the world's largest freshwater fish and are native to the Amazon and Essequibo river basins of South America (Arapaima arapaima specifically localized to the Guyana region). This group of fishes is listed as a CITES threatened species. Assessing the effects of catch-and-release angling on arapaima will be critical to a sustainable fishery.
Angling events will cause physiological disruptions that may have consequences compromising the health and survival of arapaima. Implementing studies are challenging and only preliminary results are presented. Stress responses after capture were measured using an array of blood chemistry parameters and various testing methodologies (laboratory assays, portable ISTAT and lactate units). Pre and post measurements are currently not possible in the field; therefore, baseline values were established using aquacultured Arapaima gigas (n = 10). Glucose levels were increased from the first to the second sampling event, suggesting that energy stores were mobilized following capture. High glucose levels are also an indication of stress. Conversely, l-lactate in the serum decreased in the post-sample event, and this may be related to anaerobic respiration at capture, followed by reduced blood lactate levels over time. Lactate concentrations can also rise in the blood with exercise or hypoxia. Cortisol results are pending and we will determine if the mobilization of glucose is due to a stress response. Field samples are currently being collected and will be compared with baseline values.
We thank Andrea and Salvador de Caries, who were instrumental in organizing, writing and facilitating the grant; the North Rupununi Amerindian villages and ecolodges for their hospitality; and to Compete Caribbean Grant (Cluster Competitiveness Improvement Plan) GY-CC3002 for funding support.
* Presenting author