The Abundance, Condition Factor and Length-Weight Relationship of Sardinella madernensis (Jenyns, 1842) from Nkoro River Niger Delta, Nigeria

摘要

The abundance, condition factor and length - weight relationship of Sardinella madernensis from Nkoro River in the Niger Delta area of Nigeria was studied from January - December 2008. The fishery of Sardinella madernensis is highly commercial and marketed canned, fresh, smoked or dried. Apart from being a cheap source of highly nutritive protein, it also contains other essential nutrients required by the body. As a food, sardines are rich in minerals. They can be consumed in a variety of ways-grilled, pickled, or smoked, to name three-though canned sardines are most popular worldwide. Sardines are rich in omega-3 fatty acids, which can help maintain a healthy heart. Recent studies suggest that regular consumption of omega-3 fatty acids reduces the likelihood of developing Alzheimer's disease. These fatty acids can also help control blood sugar level. Not only are sardines high in omega-3 fatty acids, but they are also a good source of vitamin D, calcium, B12, and protein. Sardines are extremely low in contaminants such as mercury. No work has been done on the length - weight relationship of Sardinella madernensis from the Nkoro River. A study of the abundance, condition factor and length - weight relationship of Sardinella madernensis from the Nkoro River adds more information on the family, Clupeidae to complement the existing data in the management and culture of the species in the Nkoro River, Niger Delta. This is essential for formulation of development plan in the fishing industry. Nkoro River is economically important and rich in biodiversity. Numerous activities such as oil exploration and production and agricultural activities go on in the region. Most of Nigeria's oil and gas reserves and production, which account for over 80% federal government's revenue, are located w ithin the N iger Delta region. The highest catch was recorded in December (6.80), followed by November(4.10), February (3.40), April (1.60), March (1.10), October(0.64), January and September(0.12). May, June, July and August recorded no catch during the study. The highest catch per unit effort (6.42) w as recorded in station 1, followed by station 2 (6.34), station 4(3.42) and 3(1.26). From a sample size of 1800 specimens, K value was 1.00 and the exponential equation was Wt = 0.0478 (TL)3.580, indicating an allometric growth pattern. The highest condition factor value (0.95) was recorded in March and November the lowest (0.8) in June. Sardinella madernensis in Nkoro river is in a stable environment and was more abundant in the dry season months of November, December and February.