Advances in Aquaculture and Fisheries Management

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 4 (1), pp. 001-006, January, 2017. © International Scholars Journals

Full Length Research Paper

Diversity, intensity and prevalence of parasites of cichlids in polluted and unpolluted end of Eleyele Dam in Ibadan, Oyo State

Simon-Oke, I.A

Department of Biology, Federal University of Technology, Akure, Ondo State, Nigeria.

Email: [email protected], [email protected]

Received 19 July, 2016; Revised 02 October, 2016; Accepted 18 January, 2017 and Published 30 January, 2017

Abstract

This study aimed to investigate the diversity, intensity and prevalence of parasites in Cichlids. A total of 354 specimens of cichlids was sampled in polluted and unpolluted ends of Eleyele River, Ibadan, Nigeria and examined for parasites. The total prevalence was 57.34%.Recovered parasites wereClinostomum tilapiae, Euclinostomum heterostomum,Neascus, Allocreadium ghanensis, Phagicola longa, Alloglossidium corti and the acanthocephalan;Acanthogyrus tilapiae and Acanthella.Clinostomum tilapiaehad higher prevalence and abundance (42.90%) with Allocreadium corti recording least abundance (0.49%).Tilapia zilli was the most abundant (41.53%) among the fish hosts but Oreochromis niloticus harboured the highest percentage of parasites (80.00%). The fish hosts in the polluted end of the river harboured the highest percentage of parasites(71.18%)against (43.50%) parasites recovered from the unpolluted end. There was a significant difference in the parasites harboured (P<0.05). Heavy infection with a broad number of parasites in fish hosts could reduce performance and productivity of the species, especially in fish farming.

Keywords:Cichlids, parasites,polluted, unpolluted, Eleyele Dam.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 4 (12), pp. 001-009, December, 2016. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper 

Growing the threatened seahorse Hippocampus erectus Perry 1810 in the laboratory

Rosana Beatriz Silveira1and José Rodrigo Santos Silva1,2

¹Laboratório de Aquicultura Marinha-LABAQUAC/Projeto Hippocampus, Porto de Galinhas, Ipojuca-PE, Brazil.
²Departamento de Estatística e Ciências Atuariais, Universidade Federal de Sergipe, São Cristóvão-SE, Brazil.

Accepted 04 June, 2016

Abstract

In Brazil, a seahorse pair of Hippocampus erectus was collected, and in captivity, mating and copulation occurred, followed by a pregnancy period of 12 days. The fry at birth had a mean height of 7.07 ± 0.947 mm and weight of 0.0037 ± 0.0049 g. The initial feed consisted of zooplankton up to the 10th day, and subsequently, they were fed nauplii and juveniles of Artemia salina and marine shrimp Litopnaeus vannamei. At 53 and 91 days of life, the animals had a mean height of 4.36 ± 0.315 and 6.03 ± 0.409 cm and mean weight of 0.377 ± 0.074 and 0.910 ± 0.172 g, respectively. At formation of the male's brood pouch, at 114 days of life, the mean height was 6.26 ± 0.374 cm and weight 0.9363 ± 0.1681 g. It was estimated that between 53 and 91 days of age, for every centimeter the seahorse grew, it gained about 0.3215 grams, where the equation height-weight obtained was W = 0.00731 L2.67728. Sexual maturity was reached at a height of 8.05 ± 0.56 cm. The size of the gestational period was 17.2 ± 6.70 days, and number of offspring produced was 377 ± 35.36 per pregnancy.

Keywords: diet, height-weight ratio, fertility, brood pouch, sex ratio, Artemia salina, Litopenaeus vannamei, Syngnathidae. 

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 4 (11), pp. 001-006, November, 2016. © International Scholars Journals

Full Length Research Paper

Genetic characteristics of hybrid populations derived by crossing Chinese and Indian pearl oysters, Pinctada fucata, based on AFLP markers

Da Hui Yu¹*, Gui-ju Huang¹, Yi-hui Guo¹, Xiao-yu Wang¹ and Ai-min Wang²

¹South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, Guangdong, China.

²Ocean College, Hainan Univeristy, Haikou 570228, Hainan, China.

Accepted 11 June, 2016

Abstract

In selective breeding, hybrid populations of pearl oysters Pinctada fucata were made by crossing Indian pearl oysters with Chinese ones. Genetic characteristics of 2 hybrid populations, Indian( ) × Sanya( ) and Sanya( ) × Indian( ) and 2 pure populations, Indian × Indian and Sanya × Sanya, were investigated using AFLP markers. A total of 230 loci were generated by 3 pairs of primer combinations. Indian-Sanya hybrid showed the highest proportion of polymorphic loci (99.6%) and the largest number of dominant, monomorphic loci (38). Gene diversity was 0.422 for total, 0.364 for average, ranging from 0.360 to 0.372. The level of gene diversity in Indian-Sanya (0.372) was significantly higher than those in the other populations (P < 0.001). Significant and high levels of overall and pairwise genetic differentiation were observed among the 4 populations as revealed by G_ST and AMOVA. These results suggested that both the hybrid and pure populations were characterized by high levels of genetic diversity and genetic differentiation at the beginning of selection, implying that artificial reproduction could have more impact on genetic differentiation than on genetic diversity at the first stage of selective breeding. Yet the high level of genetic divergence among populations suggested that monitoring changes of genetic variation of selected strains is necessary and critical for rational management of brood stocks in selective breeding practice.

Key words: AFLP, gene diversity, genetic differentiation, pearl oyster, hybrid population.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 4 (10), pp. 001-006, October, 2016. © International Scholars Journals

Full Length Research Paper

Genetic diversity of small yellow croaker Larimichthys polyactis revealed by AFLP markers 

Zhi Qiang Han¹, Long Shan Lin², Bo Nian Shui¹ and Tian Xiang Gao^{1, 2}*

¹Fishery College, Zhejiang Ocean University, Zhoushan. 316004 P. R. China.

²The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003 P. R. China.

Accepted 07 May, 2016

Abstract

The population genetic structure of small yellow croaker Larimichthys polyactis in the Yellow Sea and East China Sea was analyzed using amplified fragment length polymorphism (AFLP). A total of 304 loci were detected by four primer combinations among 53 individuals collected from four locations representing three stocks of small yellow croaker, 231 of which were polymorphic (75.99%). The proportion of polymorphic loci and Nei’s genetic distances for four populations ranged from 58.11% to 69.43% and from 0.1076 to 0.1331. AMOVA analysis and pairwise F_ST revealed significant genetic differentiation among four samples, supporting separate stocks in this species and endemic branch tribes in South Yellow Sea stock. The UPGMA tree also revealed the significant geographic structure in this species. Pattern of isolation by distance was observed in this species, indicating that significant genetic differentiation among localities of small yellow croaker was mainly due to the geographic distance. Besides geographic distance, the migratory behavior might be another factor, which influences the genetic structure of this species.

Key words: Larimichthys polyactis, small yellow croaker, genetic structure, AFLP.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 4 (7), pp. 001-007, July, 2016. © International Scholars Journals

Full Length Research Paper

The fish industry in Eritrea: from comparative to competitive advantage

Teweldemedhin, M. Y

¹Department of agriculture, Polytechnic of Namibia, Namibia. E-mail: [email protected]. Tel: +264 61 207 2030; fax +264 61 207 2143

Accepted 19 April, 2016

Abstract

The paper examines the main constrains in stimulating extent of production driven supply chains, that could able to transform into market driven supply chain management.; Questionnaires, were developed and administered to marketing agents using purposive sampling, with the application of Porter’s diamond of national competitive advantage. Red sea being underexploited resource; and it is unique opportunity for the development of the country (MOF, 1997) . However, this comparative advantage has never been converted to competitive advantage. Comparing to the percentage of fish population with in 100km from the coastal, Eritrea has the larger fish resource concentration in the region (73%). However, the sector has never made significant contribution to the country food security. The study confirms that all the role payers in the fish market chain and policy makers need to take a strategic approach, in identifying target markets, and ways to build strong and sustainable production. Moreover, all stack holder in the sector needs to formulate how to move up to: the value chain; niche marketing opportunity; converting comparative into competitive advantage; specifically focus on the services revolution; and overcoming technical and structural barriers.

Key words: supply chain management, comparative advantage, competitiveness and porter analysis.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 4 (6), pp. 001-010, June, 2016. © International Scholars Journals

Full Length Research Paper

Toxicity of glyphosate herbicide on Nile tilapia (Oreochromis niloticus) juvenile

Ayoola S.O

Department of Marine Sciences, University of Lagos, Akoka, Yaba, Lagos State, Nigeria. E-mail: [email protected]. Tel: 234-0803-4650102.

Accepted 24 November, 2015

Abstract

Fish are particularly sensitive to a wide variety of agrochemicals including glyphosate herbicide that may arise from not only deliberate discharge of these chemicals into waterways but also from approved agricultural practices. In the present study, the toxicity of glyphosate an herbicide was investigated with emphasis on histopathological effects. Nile tilapias (Oreochromis niloticus) juvenile 15 ± 1.0 g were exposed to 0, 2, 9, 30, 97, 310 mg/l of glyphosate. The lethal concentration (LC₅₀) value of glyphosate was 1.05 mg/l for 96 h of exposure. Glyphosate concentration corresponding to the 96 h LC₅₀ values for juvenile tilapia was used to study the effects of glyphosate exposure for 4 days in inducing histopathological changes of gills, livers, kidneys and brains. In the gills, filament cell proliferation, lamellar fusion, lamellar cell hyperplasia, and epithelial lifting were observed. In the liver, there was vacuolation of hepatocytes and necrosis. Kidney lesion consisted of hyaline droplets in the tubular epithelial cells and pkynosis. The brain lesion also consisted of generalized neuronal degeneration and spongiosis. The changes in these tissues occur predominantly in the 96 h exposure. Respiratory stress, erratic swimming and instant death of fish were observed in exposed fish, which varied with the concentration of the toxicant and this showed that mortality increased with increase in concentration. Glyphosate is highly toxic to Nile tilapias, which are more susceptible to this herbicide; therefore their use near fish farm or in area close to aquatic environment should be discouraged.

Key words: Nile tilapia, Oreochromis niloticus, glyphosate toxicity, histopathology.