Potential Impacts of Climate Change on the Inland Fisheries of Arid and Semi-Arid Regions of Africa

Inland fisheries of arid and semi-arid regions of Africa are seriously threatened by negative impacts of climate change. Literature and several models show increase in temperature of 1.1oC in some areas. Sea level rise is projected to increase to 0.8 m by the year 2100. Fish yields have increased almost linearly by around half a million metric tons per decade over the past 60 years, while clear cyclical variations in the residuals of about 20 years' periodicity above and below the trend line have been observed. Although fisher folks, their communities, and local institutions are already constantly adapting to various forms of change, flimsiness in the wider governance and macro-economic environment has weakened the overall adaptive capacity of these regions and fishers are vulnerable to projected climate change. For significant benefits of inland fisheries to be accomplished, planned adaptation at scales from the local to the regional is very necessary.

Morphometric Evaluations and Yields from Commercial Cuts of Black Pacu Colossoma macropomum (Cuvier, 1818) in Different Body Weights

For the Amazon, it is important to encourage the production of native fish, since there are several species of zootechnical interest. For this, it is necessary to know the species since its acquisition, production, processing, and marketing. Therefore, the aim of this study was to analyze the yield, correlations, and profitability of different cuts of black pacu (Colossoma macropomum) in five weight categories. Data from 220 black pacus were obtained, with a weight range of 2725 ± 1975 g. Yields of commercial cuts and morphometric measurements were evaluated in five weight classes. Kruskal–Wallis test (α = 0.05) was used to compare the average income. And, to verify the correlation between the morphometric measures and the yields, Spearman’s correlation was performed (α = 0.05). To obtain the profit of the weight classes due to the cut produced, an economic analysis was carried out considering the cost of buying the fish. Yields of fillet, ribs, and steak were higher in classes 3 and 4, while in the same classes, the yield of residues was the lowest. Despite classes 1, 2, and 5 showing lower yields, the economic analysis presented that the production of fillet and ribs was profitable. The measures of total length and standard length have a high positive correlation with the yield of meat in all classes, as well as the average circumference and caudal circumference in classes 1, 2, and 4, which can be used to determine the yields of this commercial cut.

Fish Feeder for Aquaculture with Fish Feed Remaining and Feed Out Monitoring System Based on IoT

Feeding fish is a process that affects fish yields. Undisciplined feeding of fish resulted in decreased quality and quantity of fish. The potential for this problem can be reduced by implementing an IoT-based technology. That technology needs to have a monitoring system for remaining feed and the success of feeding. This study using a proximity sensor and infrared distance sensor for the monitoring system for the fish feeder. The results obtained are that the infrared distance sensor can provide information about the remaining fish feed more accurately after being calibrated, the average percentage error of the total test is 5,1%. While the proximity infrared sensor can provide information on the success of throwing feed, from the total testing of the proximity sensor, the success rate of detecting throw feed is 100%. Both information can be monitored via the Blynk platform on the user’s smartphone.

Intensive pond culture of Pangasius hypophthalmus in the Mekong Delta, Vietnam.

Silver striped catfish (Pangasius hypophthalmus), 'ca tra' in Vietnamese, has been cultured intensively in cages in the Mekong Delta, Vietnam, for at least 30 years, but pond culture of this species is traditionally semi-intensive. Recently, intensive pond culture of the species has been developed. A study of P. hypophthalmus intensive pond culture was conducted in Thotnot and Omon Districts, Cantho City. The stocking density is 10-20 fingerlings m-2. Fish are fed with both artificial and farm-made feed. After 6 months of culture, fish yields ranged from 189 to 212 t ha-1 in experimental ponds. With good water quality management, meat is white and suitable for export. Intensive pond culture of this catfish has high potential to increase aquacultural production and improve farmers' income in the Mekong Delta of Vietnam. Production from farmers' ponds range from 50 to 300 t ha-1 at stocking densities of 8-40 fingerlings m-2.

Culture-based fisheries - oxbow lakes.

Oxbow lakes or baors are a major resource for culture-based fisheries in Bangladesh. Most of the oxbow lakes are situated in the southwest part of the country, mainly in the five districts of Chuadunga, Faridpur, Jessore, Jhenaidah and Kushtia. Traditionally fishers catch wild fish from the lakes. After implementation of the second Oxbow Lake Project (OLPII), fish yields increased tremendously through culture-based fisheries management. Current yields in oxbow lakes average 760 kg ha-1 year-1, while some lakes produce 1,800 kg ha-1 year-1 (Ramboll, 1998; Ahmed et al., 2003). The oxbow lakes are managed through organized Lake Fishing Teams (LFTs) and Fish Farmer Groups (FFGs), both of them raising fish in oxbow lakes and in so-called "baor fish ponds". Fish production has been increased 3-10 times compared to pre-OLPII intervention with institutionalized fisheries management. The LFTs and FFGs manage the lake properly. Fingerlings are stocked to increase fish production and provide income from the culture-based fisheries. In the baors, 86% of FFG members were female and 67% of women participated in fisheries-related activities.

Potential Impacts of Climate Change on the Inland Fisheries of Arid and Semi-Arid Regions of Africa

Inland fisheries of arid and semi-arid regions of Africa are seriously threatened by negative impacts of climate change. Literature and several models show increase in temperature of 1.1oC in some areas. Sea level rise is projected to increase to 0.8 m by the year 2100. Fish yields have increased almost linearly by around half a million metric tons per decade over the past 60 years, while clear cyclical variations in the residuals of about 20 years' periodicity above and below the trend line have been observed. Although fisher folks, their communities, and local institutions are already constantly adapting to various forms of change, flimsiness in the wider governance and macro-economic environment has weakened the overall adaptive capacity of these regions and fishers are vulnerable to projected climate change. For significant benefits of inland fisheries to be accomplished, planned adaptation at scales from the local to the regional is very necessary.