Advances in Aquaculture and Fisheries Management

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 8 (2), pp. 001-008, February, 2020. © International Scholars Journals

Full Length Research Paper

Diversity of the edible fishes of the Lagos Lagoon, Nigeria and the public health concerns based on their Lead (Pb) content

F. E. Ajagbe¹, A. O. Osibona² and A. A. Otitoloju¹*

¹Department of Zoology, Faculty of Science, University of Lagos, Lagos, Nigeria.

²Department of Marine Sciences, Faculty of Science, University of Lagos, Lagos, Nigeria.

Accepted 24 October, 2019

Abstract

In this study, a total of eighteen fish species were recorded in the Lagos Lagoon, Nigeria during a one year survey. Among the animals species recorded, the following, Galeoides decadactylus, Dentex gibbosus, Elops lacerta, Scomber japonicus, Ethmalosa fimbriata, Lutjanus agennes, Caranx senegallus, Callinectes amnicola, Paeneus notialis and Mytilus edulis were considered to be abundant in the Lagos lagoon based on the frequency of occurrence in fishermen catches. The analysis of the lead content in muscles of the edible fisheries revealed that the animals accumulated measurable quantity of lead in the edible parts. The level of lead detected in most (12 out of 18 species) of the fisheries species were found to be lower than the daily allowable concentration of 2.0 µg/g standard recommended by the World Health Organisation (WHO). Fishes species with high level of lead in their edible parts include Senegal jack, C. senegallus (2.188 µg/g), Bobo croaker, Pseudotolithus elongatus (2.024 µg/g), Cassava croaker, Pseudotolithus senegalensis (3.157 µg/g), crayfish, Penaeus notialis (25.46µg/g), edible mussel, Mytilus edulis (17.69 µg/g) and crab, Callinectes amnicola (10.19 µg/g). The mean levels of lead in Mytilus edulis, Penaeus notialis, and Callinectes amnicola collected from the Lagos lagoon were about 8 to 24 times higher than the WHO daily allowable standards for lead in sea foods and are therefore unsafe for human consumption. The need for regular monitoring of the levels of metals and other contaminants in edible fisheries resources and collaboration between environmental, health and food agencies to avert human tragedies due to lead accumulation are discussed.

Key words: Bioaccumulation, lead, industrial pollution, aquatic ecosystem, biomonitoring.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 8 (2), pp. 001-008, February, 2020. © International Scholars Journals

Full Length Research Paper

Effect of dietary protein, lipid and carbohydrate contents on the liver composition and enzyme activity of Cyprinus carpio communis fingerlings

Muzaffar Ahmad.*, Qureshi T. A. and Singh A. B.

Department of Zoology and Applied Aquaculture, Barkatullah University, Bhopal, M .P. (462026), India.

Accepted 21 October, 2019

Abstract

This study aimed to determine a feed formulation with best protein to energy ratio which would result in better liver composition and enzyme activity of Cyprinus carpio communis. Fingerlings having average weight 1.64 g ± 0.13 and length 5.26 ± 0.10 cm were fed on four different formulated feeds and a control feed (each in a triplicate set), 6% of their body weight, three times a day, during 90 days. Feeds were formulated using ground nut oil cake, mustard oil cake, rice bran, wheat bran, fish meal and soybean meal in order to suffice the balanced need of protein and energy of the common carp. Liver composition and acid and alkaline phosphatase activity of fingerlings were measured. There was a significant increase in liver lipid content with the increase in dietary carbohydrate level. The ACP and ALP activity was the maximum in the fingerlings fed on the diet having optimum protein to energy ratio of 20.54 mg protein/Kj. This work concluded that a diet containing 40% protein, 9.31% lipid and 10.08% carbohydrate is the best one for a more profitable and successful culture of the common carp.

Key words: Protein to energy ratio, carp production, acid phosphatase, alkaline phosphatase.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 8 (2), pp. 001-009, February, 2020. © International Scholars Journals

Full Length Research Paper

Growth response and ionic regulation in common carp (Cyprinus carpio L.) after chronic dietary copper exposure and recovery

Ajani, E. K¹ and Akpoilih, B. U²*

¹Department of Wildlife and Fisheries Management, University of Ibadan, Ibadan, Oyo State, Nigeria.

²Department of Animal Science and Fisheries, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria.

Accepted 21 October, 2019

Abstract

Effects of exposure of common carp juveniles (Cyprinus carpio L.) to dietary copper and its recovery rate were investigated with the aim of determining the growth and physiological impact. The fish were fed elevated copper diets (1000 and 2000 mgCukg^-1 as diet 2 and diet 3 respectively) and control diet (5 mgCukg^-, as diet 1) for 42days and were then fed the control diet for a further 21days. After 42days of exposure to elevated copper diets, growth performance examined showed that there was significant increase at (p<0.05) in feed intake, %body weight, weight gain and condition factor by fish fed diet 2 compared to diet 1 and diet 3. There was, however, no difference in specific growth rate, feed conversion ratio, in all treatments (p>0.05). Hepatosomatic index increased significantly in fish fed both elevated diets compared to control diet (p<0.05). Recovery period on normal diet (control) showed no significant effect of copper recovery on fed intake, weight gain, %body weight, specific growth rate and feed conversion ratio in all treatments (p>0.05), but, fish fed diet 2 showed a significant reduction in condition factor compared to other diets (p<0.05). Tissue Na⁺, Ca²⁺ K⁺ were disturbed throughout the experiment with sodium increasing from 257.82±2.50 to 388.14±1.32 mmol/g and calcium increasing from 499.54±6.81to 1025.94±9.16mmolg^-1 reducing gill copper from 11.63±0.37to 0.00±0.00 mgCukg^-1. Intestinal copper decreased from 14.93 ±0.1 to 0.00±0.00 mgCukg^-1 as a result of sodium increasing from 130.30±5.12 to 438.72±2.44 mmolg^-1. Increased gill copper of the 1000 mgCukg^-1 diet exposed fish during exposure compared to the control was due to copper induced decrease in plasma ion regulatory sodium (Na ATPase activity), which protected fish from direct toxicity effect and could also suggest another pathway other than the common Na/Cu apical channel shared between sodium and copper through which copper binds to fish gill; diet 2 fish showing significant increase at (p<0.05) in haematocrit, red blood cell, white blood cell and neutrophil, and a significant reduction in lymphocyte and mean cell haemoglobin compared to diet 1 and diet 3, (p<0.05). This increase in blood indices is indicative of stress onset to which fish fed diet 2 is subjected. Fish fed diet 3 showed significant reduction in haematocrit, red blood cell, white blood cell and increased lymphocyte (p<0.05) and became anaemic with severe skin discoloration, indicative of a worsening effect of excess dietary copper exposure on the fish. There were no significant differences in moisture content of all tissues during and after copper exposure (p<0.05). Gills of fish fed diet 3 increased post-exposure, indicative of protection of the structural integrity of the gill to prevent hypoxia through oxygen supply from water.

Key words: Chronic, dietary copper, growth, ionic regulation, exposure, recovery, common carp.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 8 (1), pp. 001-006, January, 2020. © International Scholars Journals

Full Length Research Paper

The sediment characteristic and benthic macro-invertebrate fauna of some fish ponds in Ife north local government area (LGA), Nigeria

A. A. Adedeji*, I. F. Adeniyi and O. R. Adetokunbo

Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria.

Accepted 21 October, 2019

Abstract

This study investigated the sediment characteristics as well as the taxonomic composition of macrobenthic invertebrate faunae of some ponds in Ife north local government area,(LGA) Nigeria. The sediments were generally sandy, moderately acidic (pH range of 3.8 to 5.8) and well drained. The organic carbon of the sediment were within the usual range of 0.5 to 5% organic carbon while the nutrients (NO₃^-, PO ₄^3-, SO₄^2-) varied from very low to moderate concentration in all the ponds. The failure for a buildup of organic material and nutrients to a very high level indicated that the wastes from the fish and exogenous feed were rapidly and completely broken down and thus does not develop to poor sediment characteristic. Macro-invertebrate fauna recorded were dominated by the molluscs typical of freshwater macrobenthic communities. Orders Architaeniaglossa and opisthobranchia were encountered with Melanoides (Melanoides) tuberculata of the order Architaeniaglossa being the most dominant taxon in the ponds. The abundance of pulmonates in these ponds showed that they were mesosaprobic – eutrophic water bodies that are slightly polluted and nutrient rich.

Key words: Poor sediment, organic carbon, acidic pH, nutrients, macrobenthic invertebrate.