FSN-FB 0013 FOOD HABITS OF

FSN-FB 0013 FOOD HABITS OF Chrysichthys furcatus (GUNTHER, 1964) FROM SOMBREIRO RIVER NIGER DELTA, NIGERIA AMAKIRI 1, N. E., J.F ALFRED-OCKIYA 2 and S. I. IORCHOR 3 1 Department of Fisheries and Aquatic Environment University of Science and Technology, Port Harcourt, Rivers State. 2 Department of Fisheries, Niger Delta University, Wilberfore Island, Bayelsa State. 3 Department of Fisheries, Akperan Orshi College of Agriculture Yandeve Benue State. Copyright 2010, Fisheries Society of Nigeria. This paper was prepared for presentation at the 25 th Annual International Conference and Exhibition in Administrative Staff College of Nigeria (ASCON), Topo-Badagry, Lagos, Nigeria, 25 th 29 th October, 2010. This paper was selected for presentation by an FISON Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Fisheries Society of Nigeria and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Fisheries Society of Nigeria, its officers, or members. Papers presented at FISON meetings are subject to publication review by Editorial Committees of the Fisheries Society of Nigeria. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Fisheries Society of Nigeria is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgement of where and by whom the paper was presented. Write Librarian, Fisheries Society of Nigeria (FISON), P. O. Box 2607 Apapa, Lagos. ABSTRACT The study examined the food habits of Chrysichthys furcatus (catfish) from the artisanal fisheries of the Sombrero River in the Niger Delta; from May 2009 to April 2010. A total of 360 specimens were used for the stomach analysis using a combination of the frequency of occurrence, gravimetric and numerical methods. Data was analysed using Shannon Weaver diversity index (H), Relative diversity (J) and index of relative importance (IRI). The results show that small Chrysichthys 28.55%, 45.23% and 39.20; fish tissues 14.70%, 9.08% and 17.44%; fish parts 25.95%, 18.76% and 18.39%, fish scale 2.60%,3.93% and 2.55%, insects 25.78%,21.95% and20.12% as the secondary and detritus 2.42%,1.06% and 2.30% as incidental food items. The Shannon Weaver and relative diversity indicate that Chrysichthys furcatus is a predator and had no food preference. INTRODUCTION Fish and fishery products are some excellent and easily digestible protein of high nutritional value and tests have shown that 85-95% of fish protein is assimilable (SFC, 2005). It is therefore recommended that fish should be used as protein source because of the possible benefits of fish oils for coronary artery disease (SFC, 2005). Fish is also a satisfactory source of magnesium, iron and copper. These minerals aid in the development of bones and teeth, haemoglobin content in blood, help to prevent nutritional anemia and the proper functioning of the thyroid gland. These minerals also reduce the cholesterol level in blood and decrease the chances of heart disease (SFC, 2005). The basic body functions like growth, development and reproduction are at the expense of food (Nikolsky, 1978). The successful culture of any fish species requires proper understanding of the various food habits and ecological niches for the production of different fish species. One common fish species often used in aquacultural projects in the Niger Delta Area is the grey catfish Chrysichthys furcatus. The C. furcatus is one of the species in genus Chrysichthys in the family Bagridae (Reed et al., 1967). Food and feeding habits of some important species has been studied by various scientists in the Niger Delta. For example Edema (1985) studies food habits of Mudskipper in Buguma River reported that diets of the fish contained a lot of detritus along with terrestrial insects, chironomids and crabs. He said that mudskipper was a strict herbivore and a frequent feeder. Alfred-Ockiya and George (1997) observed that, based on stomach content analysis Pomadasys peroteti is a predator feeding on invertebrates (penaeid shrimps, callianassids, polychaetes and hermit crabs) and fishes.

296 Amakiri N. E., Alfred-Ockiya J.F & Iorchor S. I. FISON EKO 2010 Abowei et al (2008) stated that Pseudotolithus elongatus is a predator, feeding on invertebrates such as penaeid shrimps. Mantis shrimps, Macrobrachium species, hermit crabs and fishes in Bonny estuary Nigeria and Oboh et al. (2003), revealed algae, diatoms, macrophytes, zooplanton, shrimps, insects, fish, fish scales, detritus, sand and unidentified materials as main food of Chrysichthys furcatus in Jamieson River, Delta State Nigeria. However there are few known studies of the species Chrysichthys furcatus from the Eastern Niger Delta (Rivers State). This study is therefore aimed at providing information on the food habits of species Chrysichthys furcatus in the family of Bagridae to complement the existing data in culture of the species. Since a good knowledge of food and feeding habits of fishes is inevitable in aquaculture. MATERIALS AND METHOD Study Area The Sombreiro River is one of the major rivers in the Niger Delta that empties into the Atlantic Ocean. It is located between latitude 4 30 and 5 30 North and longitude 5 30 and 6 30 East. The river is relatively narrow and deep, it widens as it flows southward (Ezekiel, 1986). The river system serves the residents in different form, ranging from domestic to commercial (cassava fermentation, washing of clothes, bathing, fetching for drinking, fishing, sand quarrying and waste disposals). Specimens of C. furcatus were collected monthly from May 2009 to April 2010. A total of 360 specimens were collected and identified in the field using various taxonomic keys (FAO, 1981; Idodo-Umeh, 1987; Lowe-McConnell, 1964; Olaosebikan and Raji, 1998). The fish were transported in ice-chest to the Fisheries Laboratory of Rivers State University of Science and Technology, Port Harcourt for preservation and further analysis. The fish were dissected and their guts removed and cut open. The stomach contents (all food items in the stomach) of the dissected fish were studied following the methods of Hynes (1950) and Hyslop (1980). Each stomach content was emptied into a Petri disc and dispersed with small quantity of distilled water. Sub-samples were taken from the stock and examined under a microscope at magnification (x 100). The stomach contents were examined both qualitatively and quantitatively by using the numerical (N), frequency of occurrence (F) and gravimetric (G) methods Pillay, 1952; and Lagler, 1973. The Shannon Weaver s diversity index was used to determine the food preference. Shannon Weavers index (H) has the form H = -K pi logpi Where K = number of categories (group), Pi = proportion of observation found in categories That is H = nlogn- fi logfi n Where fi = number of groups in I, n = fi, H = Shannon Weaver s diversity index. Also, J = H H max. The relative diversity (J) which indicates the evenness of the composition of food item was estimated as the equation. Where J =Pielous index of evenness, H max =Maximum possible diversity =log S S =number of species or categories (Alfred-Ockiya, 2001). An index of relative importance for all prey items combined was calculated with the formula IRI = (C n + C w ) F Where IRI = index of relative importance C n = percentage of numerical composition C w = percentage of gravimetric composition F = percentage of frequency of occurrence.

297 Food Habits Of Chrysichthys Furcatus (Gunther, 1964) From Sombreiro River Niger Delta, Nigeria FISON EKO 2010 The dietary components for the species examined were expressed as percentages. The most important food item was determined by using the index of relative importance (IRI) ( Backok et al, 2004). RESULTS AND DISCUSSION Out of the 360 specimens examined, 79% contain various food items in their stomach while 21% were empty as shown in Table 1. The food items found were small Chrysichthys, insects, fish tissue, partly digested fish, fish scale and detritus. The stomach content analysis based on a combination of numerical, frequency of occurrence and gravimetric methods shows that C. furcatus is a predator. The fish fed on Chrysichthys, insects, fish tissue, fish scale and detritus. This finding agrees with the results of Oboh et al, (2003) that C. furcatus fed on insects, fish, fish scales, detritus and shrimps. Nikolsky, (1978) stated that, the Bagridaes are very predatory. The Shannon- Weaver diversity index (H) calculated was 0.66(frequency of occurrence), 0.60 (numerical), and 0.64 (gravimetric). The Shannon-Weaver s diversity index indicates a moderate diversity of food intake. The high relative diversity index (J) of 0.76, 0.83 and 0.87 for numerical, gravimetric and frequency of occurrence methods respectively, observed for C. furcatus in the study indicates the evenness of food items in the stomach of the fish examined. Alfred-Ockiya and George (1997) recorded J values of 0.75 G, 0.91 F and 0.97 N for Pomadasys species from the New Calabar River, Niger Delta. Alfred-Ockiya (2001) also recorded high J. value of 0.61 N and 0.75F for Porogobius schelgelii from the Elechi Creek Niger Delta. Also, Abowei et al. (2008), reported high J value of 0.73 N, 0.75 G and 0.87 F for Pseudotolithus elongatus from Bonny Estuary Niger Delta. The relative diversity index (J) was high, it ranged from 0.76 to 0.87 Table 1. The Index of Relative Importance (IRI) of food items calculated is presented in Table 2. From table 2 small Chrysichthys had IRI value of 2410.48 which is 49.46%, insects with IRI 1084.31 and 22.25%, fish tissue 390.11 and 8%. Others are partly digested fish with IRI 964.04 and 19.78%, fish scale 16.85 IRI and 0.35% and detritus 8.13 IRI and 0.17%. This results indicated that small Chrysichthys is the main food item of C. furcatus. However Backok et al (2004) reported that the high number of frequency of occurrence of certain prey item in fish diets does not mean that the given food types are of nutritional importance to the consumer. The IRI percentage by number over emphasizes the importance of smaller prey that weigh less than larger prey. According to scientist the percentage by weight emphasized the importance of large prey. CONCLUSIONS Based on the results of this study, it can be concluded that Chrysichthys furcatus from Sombrero River in Niger Delta had Chrysichthys (fish) as the primary food item, insects as secondary food item and detritus as an incidental food item. This could imply that small Chrysichthys are more plentiful in the environment, which may indicate a nursery ground for Chrysichthys furcatus. ACKNOWLEDGEMENT The field and laboratory assistance from Mr. Hanson Uyi is highly appreciated. REFERENCES Abowei, J.F.N; Tawari, C.C; George, A.D.I. and Amakiri, N.E (2008). A study of the food habit of Pseudotolithus elongatus (Bowdich, 1825) from Bonny estuary, Niger Delta Nigeria. Afri. J of Appl. Zool. & Environ Biol. Vol. 10: pp27-31. Alfred-Ockiya, J. F. and George, A.D. I.(1997). A study of food habits of The Parrot grunt Pomadasys peroteti (Cuvier, 1825) from New Calabar River, Rivers State,

298 Amakiri N. E., Alfred-Ockiya J.F & Iorchor S. I. FISON EKO 2010 Nigeria. Global J. of Pure and Applied Sci.4(3) pp 233-236. Alfred-Ockiya J.F.(2001). Study of food habits of Goby, Paragobius Schleaelui (Gunter, 1861) from Elechi Creek Off Bonny River Niger Delta Nigeria. J. of Aquatic Sci. 15: pp79-82. Bachok, Z.; Mansor, M. I and Noodin, R. M (2004). Diet Composition And food habits of demersal and Pelagic Marine fishes from Terengganu waters east coast of Peninsular Molayia. Naga. World Fish Center Quarterly vol. 27 (3&4) pp41-47. Edema, S. A. (1985). Brackish water fishery biology 4 th Edition Bull Fish Resource Board Can.(19):pp 1-382. Ezekiel, E. N (1986). Longitudinal zonation of ichthyofauna of the river Sombreiro Rivers State (unpublished B. Sombrero River B.Sc project Rivers State University of Science and Technology Port Harcourt p74. FAO (1981). Species Identification Sheets for the Eastern Central Atlantic Area.34(11) Rome.45. Hynes, J. P.(1950). Bulletin of Fisheries Statistics, CECAF Statistical Bull 1994 pp 7-10. Hyslop, S.E. (1980). The food and feeding habits of grey mullet species in Lagos London J. Fish Biol. pp 151-156. Idodo-Umeh, G. (1987). Studies on the fish community of River Ase, Bendel State, with special emphasis on The food and feeding habits of Ctharinidae, Bagridae, Schilbeidae and Mochokidae. PhD Thesis, University of Benin City, Nigeria pp 1-412. Lagler, K. F.(1973). Freshwater Fishery Biology. Second Edition. Dobuque W. M. C. Brown Company Publishers: p421. Lowe-Mc-Connel, R.H.(1964). The fishes of the Rupununi Savanna district of British Guiana, South America. Part 1 Ecological groupings in fish species and effects of the seasonal cycle on fish. J. Linn. Soc.(Zool.) 45: pp103-144. Nikolsky, G. V. (1978). The ecology of fishes. T. F. H. Publications, Inc. Ltd. p 372. Oboh, I. P; Edema, C. U; Tango, O. L (2003). The food and feeding habits of fishes of the Jamieson Rivers Nigeria. Pakistan J. of Scientific and Industrial Research: vol. 46 No. 4 pp 255-260. Olaosebikan, B. D. and Raji, A. (1998). Field guide to Nigeria Freshwater Fishes. Federal College of Freshwater Fisheries Technology, New Bussa p106. Reed, W. Burchard, U. J; Hopson, A. J; Jannes, J; and Yaro, I. (1967). Fish and Fisheries of Northern Nigeria Min. Of Agric. Zaira Nigeria p226. Saudi Fisheries Company (SFC) (2005). Nutritional value of fish. http://www.saudi-fisheries.com.

299 Food Habits Of Chrysichthys Furcatus (Gunther, 1964) From Sombreiro River Niger Delta, Nigeria FISON EKO 2010 Table 1: Summary of food items in the stomach of C. furcatus from Sombreiro River using frequency of occurrence, numerical and gravimetric methods May 2009- April 2010 Food item Frequency of Percentage frequency Numerical Percentage numerical Gravimetric Percentage gravimetric occurrence Chrysichthys 165 28.55 598 45.23 176.89 39.20 Insects 149 25.78 290 21.94 90.80 20.12 Fish tissues 85 14.70 120 9.08 78.70 17.44 Partly digested fi 150 25.95 148 18.76 83.00 18.39 Fish scales 15 2.60 52 3.93 11.50 2.55 Detritus 14 2.42 14 1.06 10.40 2.30 Total 578 100 1322 100 451.29 100 H 0.66 0.60 0.64 H max. 0.76 0.79 0.77 J 0.87 0.76 0.83 No. of fish 360 360 360 stomach examined No. of 284 284 284 stomachs with food. Empty stomachs 76 76 76 Table 2: Index of relative importance (IRI) and percentage IRI of food items in the stomach of C. furcatus from Sombreiro River May 2009- April 2010 Food items Frequency % Numerical % Gravimetric % Index of % IRI Frequency Numer. Gravim. relative importance (IRI) Small 165 28.55 598 45.23 176.89 39.20 2410.48 49.46 Chrysichthys Insects 149 25.78 290 21.94 90.80 20.12 1084.31 22.25 Fish tissue 85 14.71 120 9.08 78.70 17.44 390.11 8.00 Partly 150 25.95 248 18.76 83.00 18.39 964.04 19.78 digested food Fish scale 15 2.60 52 3.93 11.50 2.55 16.85 0.35 Detritus 14 2.42 14 1.06 10.40 2.30 8.13 0.17 Total 578 100 1322 100 451.29 100 4873.92 100