Advances in Aquaculture and Fisheries Management

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 6 (9), pp. 001-012, September, 2018. © International Scholars Journals

Full Length Research Paper

Reproductive biology and some observation on the age, growth, and management of Tilapia zilli (Gerv, 1848) from Lake Timsah, Egypt

Waheed Farg-Alla Mahomoud¹, Amal Mohamed Mahmoud Amin², Kamal Fathey Elboray¹ Amal Mohamed Ramadan and Magdy Mostafa Kamal Osman EL-Halfawy¹*

¹Fish Reproduction and Induced spawning Laboratory, Aquaculture Division, National Institute of Oceanography and Fisheries, Suez, Egypt.

²Stock Assessment Laboratory, Fisheries Division, National Institute of Oceanography and Fisheries, Suez, Egypt.

Accepted 12 March, 2018

Abstract

In the present investigation, some biological aspects of Tilapia zillii from Lake Timsah were studied. This was carried out on 700 fish samples collected during the period from October, 2002 to September, 2003. Total length of females ranged from 7 to 16 cm and males from 8 to 21cm. Age determination based on length frequency distributions showed that the life span are two and four years for females and males, respectively. Estimates of growth parameters are widely used for detailed assessment and modeling of fish species and fisheries. The length-weight relationship, age at length zero (t_o), growth coefficient (K), asymptotic length (L∞) and rates of natural (M) and total mortality (Z) were estimated for T. zillii from Lake Timsah. Length-weight relationships were calculated from individual fish length and weight records collected from sampling using gill nets. Analyses were obtained by sampling direct from the fisher’s catches. Data were analyzed using the FISAT software. T. zillii, the estimate of K was 0.320 and 0.680 year^-1 for males and females, respectively, whilst L∞ was approximately 22.05 and 17.85 cm, for males and females, respectively. T. zillii (males) had the lowest value of K and the largest L∞ than females. Natural mortality was the lowest for T. zillii (females) (M=0.464 and 0.38 year^-1) and fishing mortality was highest for T. zillii (males) (F=2.656, 1.88 year^-1). In addition, exploitation rate was estimated at E=0.83 and length at first capture (L_c) was calculated at 11.30 cm for males while E=0.78 and (L_c) was estimated as 6.68 cm for females. The majority of fish caught of the main commercial species in the Lake Timsah fishery were from the first age group, at a size far below the optimal length at capture. This suggests growth overfishing for T. zillii in Lake Timsah.

Key words: Lake Timsah, Tilapia zillii, age and growth, mortality, gonadosomatic index, length at first maturity, population structure.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 6 (7), pp. 001-006, July, 2018. © International Scholars Journals

Full Length Research Paper

Successful artificial reproduction of the African carp: Labeo parvus Boulenger, 1902 (Pisces: Cyprinidae)

Elie Montchowui^1,2*, Clément A. Bonou³, Philippe Lalèyè², Jean-Claude Philippart⁴ and Pascal Poncin⁴

¹National Higher School of Agricultural Sciences and Techniques of Kétou, University of Abomey-Calavi, 01BP526 Cotonou, Republic of Benin.

²Laboratory of Hydrobiology and Aquaculture, Faculty of Agricultural Sciences, University of Abomey-Calavi, 01BP526 Cotonou, Republic of Bénin.

³Laboratory of Applied Biology Research, Polytechnic School of Abomey-Calavi, University of Abomey-Calavi 01 BP 2009 Cotonou, Republic of Benin.

⁴Behavioural Biology Unit, University of Liège, 22 quai Van Beneden 4020 Liège, Belgium.

Accepted 14 March, 2018

Abstract

The effectiveness of hormonal treatments to induce gamete emission in Labeo parvus was investigated in two spawning seasons (2007 and 2008). Brood fishes measuring 15 to 30 cm were gill netted in the Ouémé River (Benin) during their migration to their spawning habitat and then held in captivity (ponds). Captive fish (N = 30 males and N = 37 females) were treated with GnRHa combined with a dopamine antagonist during their natural spawning season from July through October. Ovulation was stimulated in four experimental groups of females by injecting Dagin (0.2 to 0.3 mlkg⁻¹ body weight) and Ovaprim (0.5 to 0.6 mlkg⁻¹ body weight). No female ovulated either in the groups receiving normal (as recommended by the manufacturers) dose injections of Dagin and Ovaprim (0.2 and 0.5 mlkg⁻¹ body weight respectively) or in the group treated with a Dagin injection of 0.3 mlkg⁻¹ body weight. Successful ovulation was only obtained with Ovaprim in the group treated with 0.6 mlkg⁻¹ body weight. Latency times ranged from 10 to 14 h after hormone injection. L. parvus eggs were nonadhesive and transparent at ovulation. Fertilisation rates ranged from 74.0 to 97.7%. Hatching occurred after 10 to 14 h of incubation at 27 to 30°C and lasted 5 to 7 h. Hatching rates ranged from 70.0 to 83.3%. Larvae were 3.0 ± 0.4 mm long (total length) at hatching. In the two reproductive seasons, fertilisation rates and hatching were not significantly different (P > 0.05). The water temperature was shown to significantly affect spawning latency and incubation time. Our study demonstrated that captive L. parvus could be successfully induced to produce sperm and ova using injection of a synthetic gonadotropin-releasing hormone coupled with a dopamine antagonist (Ovaprim). Their ova could also be artificially fertilised in an experimental hatchery at water temperatures ranging from 27 to 30°C. The results obtained indicate that Ovaprim is the most effective agent for inducing artificial reproduction in L. parvus.

Key words: GnRH analogues, Induced spawning, Labeo parvus.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 6 (5), pp. 001-004, May, 2018. © International Scholars Journals

Full Length Research Paper

Growth, survival and proximate body composition of Labeo rohita larvae fed artificial food and natural food organisms under laboratory condition

Yahya Bakhtiyar¹*, Seema Langer¹, S.K. Karlopia¹ and Imtiaz Ahmed²

¹Department of Zoology, University of Jammu, Jammu-1800 06, India.

²Department of Zoology, University of Kashmir, Srinagar-1900 06, India.

Accepted 11 January, 2018

Abstract

This investigation was carried out to study the effect of different live feed and dry feed on growth and survival of Labeo rohita at a stocking density of 20 larvae per trough having 10 L of water. The increase in weights and lengths were used as measures of growth. The duration of the experiment was 30 days. Seven dietary treatments were tested viz. Artificial diet with 45% protein (LFr1), rotifers like Asplanchna and Brachionus (LFr2), wild zooplankton (LFr3), bioenriched zooplankton (raised on Chlorella, cod liver oil and vitamin C) (LFr4), Artemia (LFr5), Chironomous (LFr6) and Oligochaetes (LFr7). Among the different treatments, larvae fed with diet LFr4 resulted in the maximum body weight gain (BWG) (13.18 ± 0.13 mg) which was significantly (P < 0.05) higher than all the treatments which followed the order of preference as: LFr5 (12.31 ± 0.10 mg), LFr3 (9.75 ± 0.08 mg), LFr2 (7.85 ± 0.10 mg), LFr7 (6.49 ± 0.15 mg), LFr6 (5.66 ± 0.13 mg) and LFr1 (4.99 ± 0.14 mg). The diet LFr4 recorded maximum survivability (92.0 ± 2.0%). All the values recorded for the BWG and survival were found to be significantly different (P < 0.05) among others. Protein and lipid content of the prawn after the treatment was found to be highest for LFr5 and LFr4, respectively.

Key words: Labeo rohita, food organisms, growth, body composition.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 6 (4), pp. 001-008, April, 2018. © International Scholars Journals

Full Length Research Paper

Economic performance of crab fishery in Lagos lagoon, Nigeria

Adeogun O. A.¹*, B. B. Solarin¹, H. K. Ogunbadejo¹, E. E. Ambrose¹, O. R. Akinnigbagbe¹, A. A. Ajulo¹, Bolaji D. A.¹, O. A. Olusola¹ and M. O. Adeogun²

¹Nigerian Institute for Oceanography and Marine Research, 3 Wilmot Point Road, Victoria Island, Lagos, Nigeria.

²Federal College of Fisheries and Marine Technology, 2 Wilmot Point Road, Victoria Island, Lagos, Nigeria.

Accepted 11 January, 2018

Abstract

The study evaluates the economic performance of small-scale crab fishery operations in terms of economic indicators and success performance during 2009 and 2010 fishing season in five lagoon systems in Lagos state. The objectives of the study were to state economic viability of the crab fishing activity and to identify factors influencing the cost structure. Initial analysis reveals that a large variation in cost structure exists in the crab fishing in Lagos lagoon. Economic results of the study showed that small-scale crab fishing have a positive net profit and fully recover their costs, with no losses. The net cash flow, economic and financial performance of the crab fishers was very satisfactory. The result shows that increasing catch decreases costs implying that scale and improving efficiency is key to reducing cost.

Key words: Crab fishery, economic viability, economic performance, returns on capital, Lagos lagoon.

Key words: Resource use, efficiency, fishers.

Advances in Aquaculture and Fisheries Management ISSN: 9424-2933 Vol. 5 (11), pp. 001-005, November, 2017. © International Scholars Journals

Full Length Research Paper

Studies on the hepatic antioxidant defense system in λ cyhalothrin-induced oxidative stress in fresh water tilapia (OREOCHROMIS  MOSSAMBICUS)

Rekha Parthasarathy* and John Joseph

Department of Zoology, Sacred Heart College, Thevara- Ernakulam Kerala, India.

Accepted 11 May, 2017

Abstract

The present study was undertaken to determine the effects of λ cyhalothrin-induced oxidative stress in fresh water tilapia (OREOCHROMIS MOSSAMBICUS) with respect to changes in the levels of lipid peroxidation [LPO], reduced glutathione [GSH], glutathione-dependent antioxidant enzymes (glutathione peroxidase [GPX] and glutathione-S-transferase [GST]) and antiperoxidative enzymes (catalase [CAT] and superoxide dismutase [SOD]). Significant (P<0.05) elevation in the level of lipid peroxidation was observed in λ cyhalothrin-intoxicated fishes as compared to controls. A concomitant (P<0.05) decline in hepatic antioxidant status was also observed. The results of the present investigation have indicated that the tissue antioxidant defense system is operating at a lower rate despite increased λ cyhalothrin-induced oxidative stress.

Key words: Antioxidant status, λ cyhalothrin, lipid peroxidation, Oreochromis mossambicus, oxidative stress, synthetic pyrethroid.