Abstract: Background and Objective: Bivalve mollusk shellfish is nutritious food in the coastal cities of the Niger Delta and many countries around the world. No attention has been paid to the pattern of consumption and preferences by the consumers of this product in this part of world. This study was conducted to investigate the consumption patterns and preferences of bivalve mollusk shellfish among coastal population of the Niger Delta. Materials and Methods: Statistically based cluster sampling method was used to implement field survey on bivalve consumption at four coastal locations through the use of questionnaire structured into different sections and administered through face to face interview. Results: Results indicated positive relationship (p<0.05) between all the respondent’s demographic variables and levels of perception toward clam, mangrove oyster and bloody cockle. The levels of preference for bivalve species showed that majority of respondents preferred clam, while knife clam had the least. Accessibility to products indicated that most of the respondents obtained the products from local market while least got their products from super market. In terms of preferred forms of consumption, 62.8% of the respondent’s preferred bloody cockle. Conclusion: The current findings provide a useful tool for producers and consumers involved in the supply chain of bivalve mollusk shellfish to understand the consumption patterns and various indicators for preferences.
INTRODUCTION
Mollusks are soft-bodied animals that are protected by hard shells. There are six major classes of mollusks of which bivalves are the most organized and specialized1. The marine bivalve species are highly successful invertebrate found in aquatic habitats throughout the world. They play an important role in the marine ecosystems by filtering water and serving as habitat and prey for a variety of sea-life. They have also been part of the diet of coastal human population and many species are also commercially important for other purposes such as pearls and shells for handicrafts, jewelries decoration and for making buttons. The most important species are the mussels, oysters, clams, cockles and scallops1,2. The pattern of their distribution is characteristically different from one location to another depending on the sediment types, variations in water salinities as well as the tidal movements3. The consumption of bivalves and other seafood is believed to provide an inexpensive source of protein with high biological value, essential minerals such as selenium, calcium, iron, phosphorus as well as vitamins4. The nutritional characteristics of bivalves vary among species and between individuals of same species. Other factors that affect their nutritional qualities include age, sex, maturation stage, origin, season, seawater, physical/chemical properties and feed composition5.
Fish and seafood products especially bivalve mollusk shellfish are currently the cheapest source of animal protein consumed by the average Nigerian and it accounted for about 50% of the total protein intake6. Bivalve mollusk shellfish are economically and nutritionally very important for human consumption and particularly playing a central role in the Niger Delta gastronomy. In Nigeria mollusk and other shellfish constitute a greater part diet of the people of the Niger Delta. According to Akankali and Nwafili7, Fisheries resources constitute both traditional and primary source of enterprise and livelihood to most communities within the Niger Delta region of Nigeria. Bivalve mollusks are highly exploited by adult female and youth of the coastal communities. The mangrove oyster (Crassosstrea gasar) occurs abundantly in the coastal swamp and estuaries of the Niger Delta where they are exploited at subsistence level. Other bivalves harvested include various species of clams, bloody cockle (Anadara senilis), Tagelus spp., among others8. At the subsistent level of their production, bivalve are usually sold or marketed either fresh or dried in local markets. Bayers and consumers include individual consumers who buy the products for home consumption, street food vendors, restaurant operators and exporters. Information obtained during the conduct of value chain assessment shows high profitability of the products9.
Currently, limited quantities of bivalve enter from Nigeria and other developing countries into international trade. Species such as oysters and clams are informally exported to relatives or close-circuit customers in niche markets. Stringent sanitary requirements are constraint to be overcome if fresh products are to be exported for the purpose of national income. Sanitary requirement and control systems must be adequately met if bivalves are to be legally exported particularly to European and American markets, including those relating to risk assessment and implementation of adequate sanitary plans and consumer safety. This as it relates to pollution resulting from petroleum exploration and production in the Niger Delta region of Nigeria. The objective of this study was to analyze the consumption patterns and preferences toward bivalve mollusk shellfish in the coastal population of the Niger Delta.
MATERIALS AND METHODS
Study area: The study area is a stretch of Atlantic coastline in the Niger Delta region of Nigeria. The Niger Delta sustains Africa’s largest and the world’s third mangrove forest, bearing not only Nigeria’s most abundant petroleum resources, but also diversified ecosystems, with numerous aquatic and terrestrial organisms. Four locations along the Atlantic coastline of Niger Delta were chosen for this study: Andoni (4°28'-4°45' and 7°22'-7°23), Bonny (4°23`-4°25` and 7°05'-7°15'), Ibeno (4°56'-4°57` and 8°07'-8°15') and Iko Town (4°20'-4°35' and 7°40'-7°50'). Bonny and Andoni are located in Rivers State while Iko Town and Ibeno are located in Akwa Ibom State both in the Niger Delta region of Nigeria. The study was carried out between the months of February to June, 2019. The locations were chosen because of their accessibility and availability of different species of bivalve mollusks and also the fact that they served as important delicacy and food for indigenous people. They also served as an important source of income and employment for the people in these coastal communities.
Analysis of consumption pattern and perceptions of bivalve mollusks: The analysis of consumption patterns and preferences toward bivalve mollusks in Niger Delta was carried out through the use of structured questionnaire. The method of Anacleto et al.10 was adopted with some modifications, the questionnaire was structured into 2 sections. The first section deal with demographic characteristics of the respondents while the second section investigated the consumption patterns and preferences toward bivalve mollusk shellfish. The questionnaire was administered using face-to-face interviewers who were natives of the communities and can communicate fluently with their local dialects. The interviewers were given a proper orientation on the objectives of the study, the content of the questionnaire and appropriate way to meet the respondents. To compute the size or the number of people to be interviewed at each study locations the equation of Dagnelie11, was used:
where, n is the total number of people in the group of concern to be interviewed, d is the expected error margin in the conclusion, which was fixed at 0.05 and p is the proportion of the group of population of concern. Two hundred and fifty questionnaires were used for this study.
Statistical analysis: Data obtained from the questionnaires were aggregated according to various indicators at each section and results expressed using percentages and number of respondents (frequencies). A chi-square (χ2) test was performed to examine the possible relationship between characteristics of respondent’s demographic variables with the levels of perceptions of bivalve mollusks12. Level of significance was set at p<0.05.
RESULTS
Demographic characteristics of the respondents: The demographic characteristics of respondents in the studied locations are presented in Table 1. They were determined using the following variables; Gender, marital status, age, educational level, employment status and monthly household income. The respondent were placed under three different age groups (20-37, 38-55 and 56-71). The highest number of respondent (46.0%) was from the age groups 38-55. Gender distributions of the respondents indicated that 64.8% of the respondents were female while 35.2% were male. The marital status of the respondents indicated that 53.2% were married, 24.0% were single, 13.2% were widows while 9.6% were separated. The educational attainment of the respondent showed that 32.8% attended colleges and polytechnic education; 20.8% had secondary education, 23.2% had university degree while 21.6% had various vocational trainings as presented in Table 1.
| Table 1: | Demographic characteristic of the respondents |
Over 70.4% of the respondents were employed out of which 8.8% are involved in farming and fishing related activities. Household available income level revealed that 35.6% of the respondents fell into income group between N41, 000-50,000.
Relationship between demographic characteristics and levels of perception toward bivalve consumption: A chi-square test indicated that statistical significant relationship (p<0.05) was observed between some demographic variables such as gender marital status, age, educational attainment, employment status of the respondents and the levels of perception toward bloody cockle consumption. However, no statistical significant relationship (p>0.05) existed between respondents place of residence and average household income on the level of perception toward bloody cockle. Also, positive significant relationship (p<0.05) existed between all the demographic variables of the respondents and the levels of perception toward Donax clam and mangrove oyster. While no meaningful relationship was found in a chi-square test between demographic variables such as consumer average monthly income and the level of perception toward knife clam.
| Table 2: | Number of respondents consuming bivalve species in Niger Delta |
| Table 3: | Preferred form of bivalve consumption by respondent in Niger Delta |
| Table 4: | Preferred place of consumption of bivalve by respondents in Niger Delta |
| Fig. 1: | Source of bivalve species by the respondents in Niger Delta |
Consumption patterns and preferences toward bivalve mollusc shellfish: The result of analysis of consumption patterns and preferences toward bivalve mollusk shellfish in the Niger Delta are shown in Table 2-4 and Fig. 1. The results of respondents consumption pattern of bivalve mollusk in the Niger Delta was determined through the following indicators, the rate of bivalve consumption, access point or point of collection, preferred form of consumption and preferred place or point of consumption. The rate of bivalve consumption presented in Table 2, based on species indicated that 37.2% of the respondents did not consumed mangrove oyster, 33.6% avoided bloody cockle while 26.0% do not consumed clam. In the case point of collection or access point, majority of the respondents got their products for local market, while less than 1% of the respondents buy from supermarket as shown in Fig. 1. When considering the preferred form of consumption, 62.8 and 57.6% of the respondent prefer cockle and clam slightly cooked while 20.4% preferred fried clam as presented in Table 3 and 4.
DISCUSSION
The consumption patterns and preferences for bivalve mollusk in the Niger delta region largely influenced by demographic characteristics of the population as well as other attributes such as low price and availability. The Niger Delta consists of rural communities and the inhabitants generally live below poverty line relying mostly on fishing and agriculture to survive13. This is also in agreement with Udotong et al.8 who investigated that bivalve mollusk such as bivalve are highly exploited by adult women and youth. The knowledge of consumption and perceptions regarding bivalve mollusk is critical in addressing fundamental challenges in the supply chain management of bivalve and other seafood. This is with emphasis on cost-effective, supply of cheap healthy foods, dietary changes for improve health as well as disease prevention being widely acknowledged.
According to Olsen14, the most important control factors influencing consumption of seafood are purchasing price and availability. This suggests the reason why average monthly income and place of residence have direct influence on consumption of bivalve mollusk. Education has been known to have an impact on seafood consumption especially bivalve mollusk as highly educated people tend to eat more seafood than people with lesser education15. It is also known that education and income levels have an effect on fish consumption16. In the present study, a meaningful relationship was found between education and consumption level and frequency. Myrland et al.17, stated that university graduates in Norway consumed more fish compared to others however, this position is in contrast with the report of Verbeke and Vackier18, who noted that people who completed a higher education do not necessary consume more shellfish especially bivalve than the less educated because of the knowledge of risk factors that are associated with bivalve, but income has proven to play a critical role on the perception and consumption of bivalve. Also the chi-square test revealed that both male and female respondents consume all the bivalve mollusks irrespective of gender. This is consistent with the report of Myrland et al.17 which indicated that there is no difference in gender regarding seafood consumption level in Norwegian households.
Bivalve mollusk shellfish have remain one of the major source of protein to Niger Delta diets and its consumption pattern has not change considering culture, poverty and environmental factors occasioned by various anthropogenic activities. Product attributes are vital in consumer decision making. The attributes such as freshness, size, appearance, taste, price and availability can directly influence the price and consumption. Also, while consumers considered these attributes, consumption decision tend to concentrate more on products freshness and size rather than cost19,20. In this present study, there was not clear distinction in reported attributes among species studied, but product availability and price are important attributes influencing choices. In the Niger Delta, the frequency or number of time of consumption indicated that most respondents consumed bivalve weekly and twice monthly. It further showed clam had the highest consumption rate of 32.4% weekly and 26.4% twice monthly. Knife clam recorded the least consumption rate of 17.2% weekly and 16.8% twice monthly. It was noted that the availability of species all round the year is serious factor affecting their consumption pattern as stated by Andalecio et al.19. Also seasonality plays an important role in bivalve availability; the author noted that more species are consumed in summer than autumn in Portugal and other European countries whereas in the Niger Delta species are available all year round. Also the frequency of consumption is an indication that bivalve apart from being a cheap source of protein is an important food for everyday life. The result obtained from the access point of bivalve shellfish in this study is consistent with the report of UNEP13 that the Niger delta region consists of rural communities whose inhabitants engage in agriculture and trading, also trading on fishery products take place mostly at the river banks in the morning, evening as well as their regular local markets days. It is important to note that there is a general lack of means of distribution, basic facilities such as electricity as well as cold-chain distribution system in the Niger Delta which is consistent with the reports of Hu et al.21, on an online study of consumer preference on aquatic products in china where it was noted that in rural areas, there are less facilities and as such only regular market serves as a point for exchange of fishery products.
The preference for slightly cook product is because of the believe that it reduces bacteria pathogens while retaining their original flavor and texture. Also, Azanza et al.22 noted that hot water baths give quicker shell opening, increased meat yield and improved sensory characteristics or bivalve meats without changing their physiochemical characteristics. Of the four species studied mangrove oyster appears to be consumed in different forms; 43.3% preferred slightly cooked, 14.4% preferred dried sample while 10.4% preferred roasted form. Dried mangrove oyster is usually sold in wet markets or vended along road sides especially in Port Harcourt a major city in the Niger Delta region of Nigeria. Very few respondents indicated interest in eating raw products. This is consistent with the report of Batzios et al.23, where the author noted that consumers of clam and other shell fish in European market are highly driven by fear of food poisoning rather than the price when choosing their preferred form of consumption. Also eating raw mollusk has been avoided because this has been link to several illnesses such as gastroenteritis, septicemia and food poisoning24. This similar trend was observed in Portugal where consumers had a strong preference (86%) for slightly cooked products10. Slightly cooked products are mostly preferred preparation method as indicated by the respondents. On the preferred place of consumption, majority of respondents prefer consuming the product from their homes. Similarly, 17.6 and 11.6% of the respondents preferred getting clam and bloody cockle respectively from hawkers/vendors. This similar trend was also observed by respondents in Philippines where over 79% preferred to consumed the product in their homes10,19, a development that is believed to be attributed product freshness, taste, flavor and issues of safety.
CONCLUSION
The analysis showed that the demographic characteristics of the people have a positive influence on consumers’ behavior. The most important species of bivalve consumed include clam, mangrove oyster, bloody cockle and knife clam. Factors such as frequency of consumption, sources of the products, preferred form and point of consumption were major indicators that were used in this study to assess the consumption pattern and preferences of bivalve mollusk shellfish. Bivalves are mostly consumed weekly at home and in a slightly cooked form in the Niger Delta.
SIGNIFICANCE STATEMENT
This survey may help producers and stakeholders involved in the trade chain of bivalve mollusk shellfish to understand the consumption behavior as well as the most important indicators of preferences involved in its purchase. In this way, producers will be able to create and adapt their products and the trade chain according to consumers’ requirements.