Short description Morphology Morphometrics Dorsal spines total : 0; Dorsal soft rays total : ; Anal soft rays : 49 - 58; Vertebrae : 62 - No serrations on the anterior part of the pectoral spine Ref. Head oval-shaped to rectangular dorsally; snout broadly rounded; eyes rather laterally placed; frontal fontanelle long and narrow; occipital fontanelle relatively long and oval shaped; 'postorbital' bones completely united; suprabranchial organ well developed; pectoral spine smooth; openings of secondary sensory canals with regular geometric pattern Ref. Coloration: preserved specimens: greyish-brown on back and sides, pale brown on belly; some specimens show a marbled colouration, particularly on posterior part of body; caudal fin often with one or more vertical cross-bars Ref. Body and fins occasionally with irregularly placed spots Ref. Denayer and M.

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The growth of the aquaculture industry in Nigeria depends to some extent on the availability of fish seeds. This study was carried out to measure the optimum growth of Heterobranchus bidorsalis and the best time to crop under maximum utilization of feed in semi-intensive pond condition. Optimum growth performances of fingerlings of artificially propagated Heterobranchus bidorsalis were investigated.

The fingerlings were stocked in three 0. Mean weight at stocking was 8. Temperature, dissolved oxygen , pH and total ammonia-nitrogen were measured in each treatment. Survival rate, specific growth rate and condition factor of fish species were also determined. Survival at harvest after 26 weeks was Standing crop at harvest was 10, kg ha There was positive correlation 0. Mean condition factor K was 1. Result demonstrated the potential of Heterobranchus bidorsalis for use in aquaculture.

It also indicates that the fish species can be grown to commercial size within 26 weeks from fingerling stage under semi-intensive pond conditions. The best time to harvest the fish for maximum gain in terms of good growth and maximum profit on feed utilization is 26 weeks after hatching. Intensification of aquaculture practices in Nigeria has been identified as one of the tools that can help in closing the gap between demand and supply of fish and fisheries products Owodeinde and Ndimele, This is particularly important in the culture of acceptable fish species Clarias gariepinus and Heterobranchus sp.

The clariid catfishes constitute an excellent food fish of high commercial value in Nigeria and some other countries of the world Adebayo and Popoola, ; Huda et al. Heterobranchus bidorsalis is one of the two main genera of the African mud catfish Clarias and Heterobranchus widely cultured in Africa, Asia and Europe Adewolu and Adoti, ; Kori-Siakpere et al. This is due to their outstanding culture characteristics such as ability to withstand unfavourable environmental conditions, efficient in utilizing various types of locally formulated fish feed, resistance to diseases, high economic potential and simple techniques in the propagation of their fingerlings Fagbenro and Sydenham, ; Dada and Olarewaju, ; Owodeinde and Ndimele, A lot of Nigerians have demonstrated their interest in catfish consumption.

This feeding habit of Nigerians tends to support the commercial propagation of clariid catfishes and this trend became noticeable since the late s. This was when it became apparent that commercially exploited clariid populations in the wild were declining but their commercial value was increasing. This situation triggered off interest in the culture of clariid catfishes as commercial food fish.

This high demand of the clariids resulted in generally high prices which serve as an added inducement to would-be fish farmers or groups interested in commercial fish culture. Studies on Heterobranchus species in Nigeria focused on stock and chromosome manipulations, performances of intraspecific hybrids and growth performances at different dietary compositions in indoor and outdoor concrete tanks Madu et al.

However, none had detailed investigation on the growth and survival of this clariid species- Heterobranchus bidorsalis under semi-intensive pond conditions.

This study is aimed at evaluating the potentials for culturing Heterobranchus bidorsalis to commercial size and using simple regression technique equation to determine the relationship between the body weight of Heterobranchus bidorsalis and the number of weeks of growth with a view of determining the optimum growth and the best time to crop under maximum utilization of feed in semi-intensive pond condition.

The fish were kept in the rearing tanks to allow them recover from stress due to transportation and acclimatized them to their new environment. They were in the rearing tanks for two weeks, during which they were fed on compounded diet.

Experimental procedure: Three rectangular earthen ponds of 20 m in lengthx10 m in width 0. Two weeks before stocking, the ponds were filled with water from the farm bore-hole, fertilized with complete in-organic fertilizer N 15 P 15 K 15 at the rate of kg ha -1 and poultry manure at the rate of kg ha -1 , then seeded with plankton collected from a culture farm pond by pumping pond water through plankton net.

At two weeks interval, the fish were sampled with a 2. Fish were not fed 24 h before the samples were collected to allow the intestinal contents to be digested. To avoid stress due to handling, the randomly selected fish were subjected to mild anesthetization in a 20 mg L -1 solution of MS tricaine methanesulfonate purchased from Sigma Chemical, St. Louis Missouri, USA. After all measurements, the fish were revived in fresh water and then returned to the ponds. On the 30th of August , the ponds were drained; all the fish were removed, counted and weighed to determine the survival rate and standing crops.

They were held in three 6 m 3 concrete tanks. Determination of water quality parameters: The following water quality parameters were measured during the study period; temperature, dissolved oxygen , pH and total ammonia-nitrogen.

Temperature was monitored with a simple mercury-in-glass thermometer graduated in 0. Analysis of growth: The linear regression relationship between body weight and the number of weeks of growth of Heterobranchus bidorsalis was calculated using this formula Uzoagulu, :. B O is the intercept on Y-axis; B 1 is the slope of the line or gradient and X 1 is no of weeks of growth.

Mean specific instantaneous growth rates SGR estimated as percentage increase in weight per growth period of Heterobranchus bidorsalis was calculated at the end of each growth period using the formula:. The calculation of SGR which accounts for both initial and final sizes is useful in comparing growth of the fish species at different sizes Brown, , This formula estimated the percentage increase in weight per growth period.

Condition factor K to determine the relative robustness i. The amount of food dispensed kg to the fish stocked in the three experimental ponds were adjusted bi-weekly by sub-sampling the population of the fish species in order to reflect the fortnightly increase in biomass using the following Stickney, :. Several investigators have recently demonstrated that Heterobranchus bidorsalis can be grown to commercial size in various types of culture systems Madu et al.

The present study yielded the best growth and production rates yet published in Nigeria on H. Growth, survival and production: During the period of study after the initial stocking of fish per 0.

Growth was rapid from May to August wish coincides with the raining season. The relationship between the body weight and the number of weeks of growth is shown in Fig. The graphical representations and the statistical computations of the body weight against the number of weeks of growth of the study fish showed that they were highly correlated.

The computation of the data provides the following:. A geometric growth curve was observed when the relationships between the two variables were plotted against each other. The observed growth curve shows the best time to harvest H.

The study shows that H. Beyond this time there was decreased efficiency of feed utilization and a decline in growth rate set in Fig. At the final harvest survival was Since no physical mortality was recorded during the study period, piscivorous birds and poaching contributed to the mortality. This practice would allow consolidation of smaller fish into fewer ponds for additional growth. The removal of larger fish would also provide early cash return and eliminate the need of looking for buyers for a large percentage of the Heterobranchus bidorsalis which would have been commercially marketable in the restaurant trade Fig.

Specific growth rate SGR and condition factor K : Daily specific growth rate declined from a maximum of 4. High initial specific growth rates that decrease with increasing age and individual fish biomass and consequent increased metabolic costs followed typical pattern of fish growth Kerby et al. Mean condition factor K for fish sampled was 1. Fish that were sacrificed after the harvest contained appreciable quantities of abdominal fat. Water quality: Water quality parameters were generally within acceptable limits.

Bore-hole water with an alkalinity of Water quality values were generally satisfactory for the growth and health of the experimental fish species Ndimele and Kumolu-Johnson, ; Ndimele et al. Values for total ammonia nitrogen did not exceed 0.

The pH ranged between 7. All these water quality parameters fall within the range reported by Huet as good for pond fish culture. Though, the FCR in most fishes e. The reason for this high FCR is not known. Since sinking pelleted feed was used, significant amount of feed might be wasted, this could account for high FCR observed in this study. We believe that feeding practices can be refined to provide more efficient conversion ratios without reducing growth rates.

In conclusion, this study has shown clearly that optimum growth and the best time to crop Heterobranchus bidorsalis under maximum utilization of feed can be determined in semi-intensive pond. We thank Mr. Austin Anetekhai and Mr.

Pascal Opuehi for their assistance in the collection of data and for taking care of the fish. Subscribe Today. Science Alert. All Rights Reserved. Research Article. Similar Articles in this Journal. Search in Google Scholar. How to cite this article: F. Owodeinde , Journal of Biological Sciences, DOI: Final length-weight relationship, correlation coefficient and condition factor of study fish.

Relationship between mean body weight and number of weeks of growth in Heterobranchus bidorsalis. Relationship between mean body weight and mean standard length of Heterobranchus bidorsalis in June. Relationship between mean body weight and mean standard length of Heterobranchus bidorsalis in July. Relationship between mean body weight and mean standard length in Heterobranchus bidorsalis.

Adebayo, O. Popoola, Comparative evaluation of efficacy and cost of synthetic and non-synthetic hormones for artificial breeding of African catfish Clarias gariepinus Burchell, Adoti,


Human uses

The dearth of African giant catfish Heterobranchus bidorsalis seeds poses great threat to its aquaculture and biodiversity, hence detailed knowledge and understanding of its embryology is indispensable for its artificial propagation and conservation programmes. Photomicrographs of extruded oocyte through all developmental cell stages of live embryo to larval stage are documented with the aid of a light microscope. The optical transparency of the developing embryo enabled us to describe its deep structures, distinctive features and characterize the stages pictorially. Blastula was featured by formation of enveloping layer and yolk syncytial layer. Neurulation period was distinct from segmentation where organogenesis was fully active. The fin bifurcation to dorsal and adipose fins was observed at third and half weeks post-hatchability with the dorsal fin length to adipose fin was 1.


Heterobranchus bidorsalis Geoffroy Saint-Hilaire, 1809

Heterobranchus bidorsalis , the African catfish or eel-like fattyfin catfish , is an airbreathing catfish found in Africa. The head of Heterobranchus bidorsalis is shaped like an oval and has a rectangular dorsum. The snout is round and the eyes are lateral. The frontal fontanelle is long and narrow while the occipital fontanelle is relatively long and is shaped like an oval.

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