ReseaRch PaPeR Journal of Agricultural and Marine Sciences 2022, 27(2): 28–40 DOI: 10.53541/jams.vol27iss2pp28-40 Received 30 Dec 2020 Accepted 15 Nov 2021 Fish By-Products Consumption and Discard Pattern in Nigeria B. Egbedi*, and A. O. Osibona B. Egbedi*( ) brakemi.egbedi@gmail.com, Department of Marine Sciences, University of Lagos, Nigeria. Introduction Fish is an important source of livelihood for peo-ple in both developing and developed countries. Its contribution to food security is particularly important in Nigeria, where malnutrition, unbalanced nutrition, protein shortage, hunger and serious health problems are widespread (Akinyele, 2009). According to Amao et al. (2006), fish contributes 13.4 kg/person per year of the animal protein consumed in Nigeria, howev- er, this value is below the global average fish consump- tion level of 20.5 kg/person per year (FAO, 2018). De- spite its significant role, fish supply in Nigeria from all its sources (i.e. artisanal fisheries, aquaculture, industrial fishing and importation) have failed to meet the coun- try’s domestic demand (Akinrotimi et al., 2011), which is on the increase due to the increasing population growth in Nigeria and changing consumers’ preferences (Adewunmi, 2015). Amao et al., (2006) argued that the short fall in fish supply in Nigeria can also be attributed to the non-maximization and sustainable utilization of aquatic resources, some of which include by-products. There is no standard definition for the term ‘by-prod- uct’ (Rustad et al., 2011). It has been defined by Kim and Mendis (2006) as fish leftovers which are not regarded as ordinary marketable products. Ananey-Obiri and Taher- gorabi (2018) defined it as the remaining parts of fish left over after processing, which are often not considered as استهالك الـمنتجات الثانوية من األسـماك ومنط التخلص منها يف نيجرياي ب .إغبدي*، و أ. أوسيبوان Abstract. Significant portions of by-products are generated and discarded throughout the fish supply chain. To reduce the discard of these by-products and ensure their proper utilization, there is a need to ascertain its discard and consumption pattern among fish consumers. The main aim of this study was to investigate the by-products fish consumers in Lagos State, Nigeria regard as waste; discard and consume. Factors which influence the discard and con- sumption of these by-products were also investigated. Using a Multistage sampling procedure, a structured question- naire was used to obtain information from 300 respondents in three Local Government Areas (LGAs) in Lagos State, Nigeria and the data collected were analyzed using descriptive and inferential statistics. The results show that the scales (92%) were the most discarded by-product followed by gut (89%), gills and fins (85%). The skin was the most consumed by-product while the gut was the least consumed. The three major reasons given by the respondents for the discard of these by-products were that they considered them uneatable, useless and a waste. Several interrelating factors, such as social factors, type of fish species and socio-demographic characteristics also influenced the by-products respondents in this study regard as waste; discard and consume. The results in this study indicated that the scales, gut, gills, and fins were largely discarded and underutilized by fish consumers in Lagos State, Nigeria. There is a need for research on sustainable ways to recover and utilize discarded by-products for the development of value-added products and for the realization of a sustainable circular economy. Keywords: Fish by-products; Waste; Fish discard; Consumption; Nigeria. الـــملخص:يتم التخلــص مــن الكثــر مــن املنتجــات الثانويــة يف مجيــع مراحــل سلســلة توريــد األمســاك. ولتقليــل التخلــص مــن هــذه املنتجــات وضمــان االســتخدام الســليم هلــا، هنــاك حاجــة للتأكــد مــن منــط التخلــص منهــا واســتهالكها بــن مســتهلكي األمســاك. اهلــدف الرئيســي مــن هــذه الدراســة هــو التحقــق مــن مســتهلكي املنتجــات الثانويــة لألمســاك يف واليــة الغــوس، نيجــراي بشــأن اعتبــار هــذه املنتجــات نفــاايت: ســواء التخلــص منهــا أو اســتهالكها. كمــا مت دراســة العوامــل الــي تؤثــر علــى التخلــص مــن هــذه املنتجــات واســتهالكها. ابســتخدام إجــراء أخــذ العينــات متعــدد املراحــل، مت توزيــع اســتبيان علــى الفئة املســتهدفة )300 مســتجيب( للحصول على معلومات يف ثالث مناطق حكومية حملية )LGAs( يف والية الغوس، نيجراي ومت حتليل البياانت الي مت مجعها ابســتخدام اإلحصاءات الوصفية واالســتنتاجية. أظهرت النتائج أن قشــور الســمك )92٪( هي عبارة عن منتجات اثنوية يتم يف الغالب التخلــص منهــا كنفــاايت، تليهــا األمعــاء )89٪(، واخلياشــيم والزعانــف )85٪(. كان اجللــد هــو املنتــج الثانــوي األكثــر اســتهالًكا بينمــا كانــت القنــاة اهلضميــة أقــل اســتهالًكا. إن األســباب الرئيســية الثالثــة الــي قدمهــا اجمليبــون علــى االســتبيان بشــأن التخلــص مــن هــذه املنتجــات هــي اعتبارهــا غــر صاحلــة لــألكل وعدميــة الفائــدة وابلتــايل مــن النفــاايت. هنالــك العديــد مــن العوامــل املرتابطــة، مثــل العوامــل االجتماعيــة، وأنــواع األمســاك واخلصائــص االجتماعيــة والدميوغرافيــة الــي أثــرت علــى إجــاابت املشــاركون يف هــذه الدراســة. أشــارت نتائــج هــذه الدراســة إىل أن القشــور، واألمعــاء، واخلياشــيم، والزعانــف يتــم التخلــص منهــا بشــكل كبــر وغــر مســتغلة بشــكل كاٍف مــن قبــل مســتهلكي املنتجــات الســمكية يف واليــة الغــوس، نيجــراي. هنــاك حاجــة للبحــث عــن االســتخدام األفضــل هلــذه املنتجــات الثانويــة مــن أجــل حتقيــق االســتدامة. الكلمات املفتاحية: منتجات األمساك الثانوية؛ نفاايت؛ التخلص من األمساك، االستهالك؛ نيجراي. 29Research Paper B. Egbedi, and A. O. Osibona fitting for human consumption. According to Rustad et al. (2011), by-products can be understood as any edible or inedible raw material remaining after the production of the main products. In this study, by-products are de- fined as any part of fish besides the flesh or fillet. In Ni- geria, the term ‘discard’ and ‘waste’ refer to two separate terms. The former refers to by-products that are thrown away by consumers or respondents for any reason, while the latter refers to by-products which cannot be used for any application (i.e., by-products considered worthless). By-products are generated during the processing of fish obtained from both capture fisheries and aquaculture (Olsen et al., 2014) and they include scales, heads, vis- cera, fins, skin, bones, and frames (Ananey-Obiri and Tahergorabi, 2018). There are varying estimates of the volume of by-products generated worldwide (Rustad et al., 2011). Pastoriza et al. (2003) claimed that by-prod- ucts make up about three-quarter of the total weight of the catch, while Suresh et al. (2018) reported that they can make up about 50-80% of the total catch, depend- ing on the fish species and level of processing. Although some of the by-products have been utilized in the pro- duction of low-price ingredients, such as fish meal, fish oil, fish silage, fish fertilizer, fish sauce (Suresh et al., 2018); the bulk of it is discarded (Falch et al., 2006) at seas, rivers or landfills. This creates disposal and pollu- tion problems as well as the underutilization of the nu- trients contained in the by-products (Suresh et al., 2018). Fish by-products contain protein, lipid, minerals (Ghaly et al., 2013) as well as other valuable compounds (Rustad et al., 2011). They can be used to produce value added products, such as amino acids, proteins, collagen, gela- tin, oil, enzymes, bioactive peptides (Ghaly et al., 2013), which in turn can be used to solve problems related to food security and help in generating additional revenue and employment opportunities in the fisheries industry. To effectively exploit these by-products generated from the fisheries industry (both from capture fisher- ies and aquaculture) in the development of value-added products, knowledge about its consumption and discard pattern among Nigerian consumers must be established. Research on the consumption, preferences, and market for by-products in Asia (Tonsberg et al., 1996); Iceland (Arason, 2003) and Norway (Jonsson and Vidarsson, 2016) have been documented. The head of fish makes up the bulk of fish by-product by volume and export from the Icelandic Fisheries. Other by-products, such as the skin is exported to countries like Canada and Spain, but a fraction is also used in the production of leather (Arason, 2003). The Chinese are acclaimed for consum- ing every part of fish, and the part of fish not eaten are largely used in Chinese traditional medicine. In Taiwan, most fish by-products are used and those not used, such as gall bladder and eyes, are sometimes exported to Ja- pan for fish oil production. Milk fish and eel offal are consumed in Taiwan. Taiwan is also known as Norway’s largest export market for Salmon heads which are used in the preparation of fish soup. (Tonsberg et al., 1996). Many Africans show a strong preference to fresh fish in its whole form, and when by-products are generated, they have been used as non-conventional supplementary feed or as ingredients for compounded feed as a source of animal protein and mineral especially in small-scale aquaculture farms in countries such as Kenya (Nyan- dat, 2007) and Nigeria. According to Ayinla (2007), fish by-products from processing companies were used in the production of fish meal for use as feed in aquacul- ture farms before the closure of the only fish meal pro- cessing plant in Nigeria. There is paucity of information on the consumption and discard pattern of fish by-prod- ucts among fish consumers in Nigeria. The knowledge of Nigerian consumers’ attitude towards fish by-products may increasingly contribute to its improvement in terms of recovery, maximization, and sustainable utilization. The main aim of this study was to investigate the by-products respondents in Lagos State regard as waste; discard and consume. Furthermore, this study aimed at determining the factors which influence the discard and consumption of by-products in the study area using three indices: Respondents’ responses, so- cio-demography and consumption of fish species. Lagos State was chosen for this study because it is a coastal state and one boasting of major fish markets with a high fish consumption pattern among its inhabitants. Materials and Methods Study Area Lagos State is located in the South-Western part of Nigeria. It is bordered in the North and East by Ogun State; in the West by Republic of Benin, in the South by the Atlantic Ocean and it stretches over 180 km along the Guinea Coast of the Bight of Benin on the Atlantic Ocean. In terms of land mass, it is the smallest state in Nigeria, yet it has the highest urban population (LASG, 2018). About 22% of its total land mass comprises an extensive network of Lagoons, rivers, creeks swamps and estuaries (Olaoye et al., 2014). Lagos which is the 6th megacity in the world is Nigeria’s economic, finan- cial, and commercial nerve center. It is dominated by the Yoruba ethic group and is divided into 20 Local Government Areas (LGAs) and 37 Local Council De- velopment Areas (LCDAs) respectively (LASG, 2018). Sampling procedure and Data Collection This study used a non-experimental survey design that consisted of the administration of questionnaires to ob- tain reliable data as well as to document respondent’s perceptions of fish by-products. The questionnaire com- prised of questions pertaining to the aim of this survey. Information on the socio-demographic characteris- tics of the respondents; possible factors that affect fish 30 SQU Journal of Agricultural and Marine Sciences, 2022, Volume 27, Issue 2 Fish By-Products Consumption and Discard Pattern in Nigeria by-product discard and the most frequently consumed fish species were retrieved. A complete list of all the local government areas, their constituencies and wards were obtained from the Lagos State Government. The target population for this study were male and female adults (18 years and above) who consume fish in Lagos State. The Multistage random sampling procedure was em- ployed in data collection as shown in Figure 1. A total of three hundred and thirty (330) questionnaires were administered to both male and female fish consumers and a quota of 55 questionnaires were administered per ward to ensure uniformity. In total, information from 300 fully completed questionnaires (50 ques- tionnaires per ward) was used to obtain the data used for this analysis. Informed consent was obtained from all respondents by seeking their approval before pro- ceeding with the questionnaire survey. To satisfy the inclusion criteria for participation in the survey, the respondents were asked whether they consume fish and if they were 18 years and above. On responding in the affirmative, the respondents in the selected build- ings/houses were included in the study population. In cases of plural eligibility in a building, all the eligi- ble respondents were selected. Visual aids in the form of pictures were incorporated in the interview process for easy identification of the listed fish by-products. Statistical Analysis The data collected for this study were analyzed using descriptive (i.e. frequency distribution and percentages) and inferential statistics (i.e. Chi-square). Chi-square (X2) test was used to check for statistical significance (P<0.05) in the relationship between the respondents’ age, sex, income, education, and the by-products they regard as waste; discard and consume. Results Socio-demographic Characteristics of Respon- dents The results of the socio-demographic characteristics of the respondents are shown in Table 1. Two-thirds of the respondents were female and about one-third were male. Majority of the respondents (42%) were within the age group 25-35 years. All the respondents had a form of formal education. Only 5% had a Masters’ degree while 54% of the respondents had tertiary education (OND/HND and Bachelors’ degree). The distribution of respondents by occupation shows that about 82% of the respondents had a source of livelihood. The results further indicate that majority (31%) of the respondents were involved in entrepreneurship. In addition, very few people (1%) were civil servants. Even though all the re- spondents had formal education and many had a means of livelihood, only about 35% earn above ₦ 50, 000. Figure 1. Multi-stage random sampling procedure used in data collection. 31Research Paper B. Egbedi, and A. O. Osibona Consumers Response on Fish By-products Fish by-products regarded as waste: The results of re- spondents’ responses on the various by-products they regard as waste is shown in Figure 2. Although there were varying responses from the respondents on the by-products they regard as waste; the results indicated that the scales were the by-products largely considered to be a waste by the respondents while the skin was the by-product least considered to be a waste. Fish by-products discarded by respondents: As shown in Figure 3, the scales were the by-products mostly dis- carded as reported by 96% of the respondents. Following the scales; the gut, fins and gills were the by-products largely discarded by more than 80% of the respon- dents. The skin was the least discarded by-product. Distribution of Consumers’ Responses Fish by-products consumed by respondents: As shown in Figure 4, the skin was the most consumed by-product. The gut was the least consumed by-product followed by the scales. The respondents’ reasons for discarding the various fish by-products are shown in Figure 5. The three major reasons which influenced the respondents’ choice for discarding these by-products were because they found them uneatable (54%) of no use to them (30%) and a waste (24%). The respondents also listed other factors which influenced their attitude towards fish by-prod- ucts consumption some of which include preference, beliefs, family upbringing and other social factors. The fish species consumed by the respondents are shown in Figure 6. Atlantic Mackerel (locally called Titus) was the fish species mostly consumed by the respondents. Inferential Statistics Chi-Square test was used to check for significant dif- ferences and to gain a deeper understanding of the re- lationship between the socio-demographic character- istics: age, sex, income and education (re-categorized) of the respondents and the by-products they discard, consume and regard as waste. There was no statistically Table 1. Percentage distribution of respondents by Socio-de- mographic characteristics. Variable Frequency (n) Percentage (%) SEX Male Female AGE GROUPS 18-24 years 25-35 years Above 35 years HIGHEST LEVEL OF EDUCATION SSCE OND/HND Bachelor’s degree Master’s degree Others OCCUPATION Entrepreneur/Business men Professional Services Artisans Students Sales representatives/Executives Civil Servants Clerical workers Unemployed MONTHLY INCOME (₦) Less than 20,000 20,000-50,000 Above 50, 000 98 202 89 125 86 116 77 83 15 9 94 58 53 52 32 4 4 3 96 100 104 33 67 30 42 29 39 26 28 5 3 31 19 18 17 11 1 1 1 32 33 35 Figure 2. Percentage frequency of fish by-products regarded as waste. 32 SQU Journal of Agricultural and Marine Sciences, 2022, Volume 27, Issue 2 Fish By-Products Consumption and Discard Pattern in Nigeria significant relationship (P>0.05) between the respon- dents’ age and the by-products evaluated. There was a statistically significant relationship (P<0.05) in the sex of respondents and certain by-products they discarded and regarded as waste. The chi-square analysis in Table 2 also shows a statisti- cally significant relationship (P<0.05) between respon- dents’ income and their response to whether they dis- carded the fins and considered it a waste. Their response to the other listed by-products were not statistically Figure 3. Percentage distribution of respondents who discard fish by-products. Figure 4. Percentage distribution of respondents who consume fish by-products. 33Research Paper B. Egbedi, and A. O. Osibona significant (P>0.05). There was no association between the education of respondents and the by-products they discarded but a statistically significant (P<0.05) rela- tionship was observed in their views on whether they regarded the bone as waste and whether they consumed the fins, skin and bones. Discussion Knowledge of fish by-products consumers regard as waste; discard and consume is essential if these resourc- es are to be harnessed and utilized effectively. In this study, the term waste and discard refer to two different terms. The scales were the by-products largely regarded as waste followed by the gut, fins, gills bone, head and skin as shown in Figure 2. A similar trend was observed Figure 5. Respondents’ reasons for discarding fish by-products fish species consumed. Figure 6. Fish species mostly consumed by respondents Inferential Statistics . 34 SQU Journal of Agricultural and Marine Sciences, 2022, Volume 27, Issue 2 Fish By-Products Consumption and Discard Pattern in Nigeria in the by-products discarded by the respondents. As shown in Figure 3, 96% of the respondents discarded the scales, thus making it the most discarded by-prod- ucts followed by the gut (89%), fins and gills (85%). The skin (3%) was the least discarded by-product. A possi- ble reason why the respondents in this study discarded certain by-products such as the scales, gut, gills and fins more than the bone, head and skin may be because they regard them as inedible and worthless. This was further confirmed from the distribution of responses on the factors influencing the discard of by-products as shown in Figure 5. where the most discarded by-prod- ucts were those considered uneatable, of no use or a waste. This finding is in agreement with Caruso (2016) who reported that more than 50% of fish by-products were discarded because they were considered a waste. Malaweera and Wijesundara (2014) also reported that certain by-product, such as the scales are discarded be- cause they are largely considered to be worthless. These by-products: scales, gut, gills, fins, bones, head, and skin are not worthless or a waste because they have potential applications in various industries such as the food, feed and pharmaceutical industries owing to their nutritional or chemical composition. Fish scale is a rich source of collagen, the most abundant protein in the body of ani- mals and one which has a vital role in the formation and maintenance of various parts of the body like the bones, ligaments, hair, nails and skin (Jonsson and Vidarsson, 2016). Collagen can be utilized in cosmetic and skin care products owing to its moisturizing, regenerating and film-forming properties (Sionkowska et al., 2020). Type I collagen obtained from the scales of Sea bream were used in the hydrolysate form and it demonstrated Angiotensin converting enzyme (ACE) inhibitory activ- ity, which can be further used in the treatment of hy- pertension (Fahmi et al., 2004). Kandyliari et al. (2020) recorded varying concentrations of proteins, lipids, fatty acids, and minerals in the head, skin, bones, trim- mings, gut and gills of large Gilthead seabream. When compared to the skin and head, the most consumed by-products in our study, Kandyliari et al. (2020) found out that the bones had a higher mineral or ash value. The gills (37.46%) and intestines (43.19%) proved to be good sources of lipids and their values were higher than the lipid content in the head (37.08%) and bones (30.56%). All the by-products had high protein values greater than 30% thus, they can be considered as potential sources of bioactive peptides and for use in the development of functional foods. Falkenberg et al. (2014) recorded radi- cal scavenging activity in gill extracts from Salmon fish. The skin of cod fish has been used in the development of wound patches and tissue regeneration solutions (Jonsson and Vidarsson, 2016). Research on the produc- tion of enzymes from fish intestines are being carried out for potential use in food, pharmaceutical, cosmet- ic, health and industrial applications (Arason, 2003). Table 2. Chi-Square test result on the socio-demographic characteristics and the by-products respondents regard as waste, discard and consume. Statements Age Sex Education Income By-products regarded as waste Head Gills Fins Gut Scales Skin Bones By-products discarded Head Gills Fins Gut Scales Skin Bones By-products consumed Head Gills Fins Gut Scales Skin Bones 4.968 8.471 4.235 2.854 0.324 4.827 0.097 7.643 0.793 6.159 1.937 6.791 1.585 3.290 6.828 0.933 0.622 1.940 3.316 2.408 0.401 2.478 14.116** 6.895* 11.775** 9.345** 1.472 8.111* 0.636 7.222* 10.589** 0.498 3.178 4.926 5.737 1.069 2.772 2.312 2.870 1.498 5.178 2.606 1.557 2.629 5.868 1.134 2.614 2.375 7.462* 4.903 0.098 4.237 1.854 3.116 2.192 2.809 2.338 0.532 8.316* 4.433 0.984 9.129* 15.136** 2.804 4.428 11.282* 1.124 8.738 3.806 1.146 6.042 2.172 10.378* 4.055 5.811 1.498 0.687 8.184 6.341 8.638 2.524 6.085 6.321 1.538 Note: *= Significant at 5% (P<0.05) and ** = Significant at 1% (P< 0.01) 35Research Paper B. Egbedi, and A. O. Osibona The results of the by-products consumed by the respon- dents indicated that the by-products least consumed were those frequently discarded and regarded as waste. Olsen (2004) opined that taste (positive effect), distaste (negative effect) and nutrition are factors that influence consumers preference for particular foods. Certain at- tributes, beliefs and social norms may also contribute to the negative effect of food attitudes. Social norms or factors which can be defined as the expectations from people in one’s family, locality or immediate social circle, play a role in determining fish consumption among peo- ple all over the world (Olsen, 2004; Rozin, 1995). During the field survey, the respondents in this study further expressed certain social bias which influenced their consumption of by-products. According to them, social factors such as family upbringing (i.e. watching their mothers discard certain by-products), beliefs (i.e. bones can choke a person to death; gills and guts contain a lot of dirt), social norms (such as the cutting off of the fins of fish by fish mongers in the markets even without be- ing asked to do so) positively contributed to why a large proportion of certain by-products such as the scales, gut, gills and fins were considered uneatable. The social bias stated by respondents in this survey was similar to the findings of Gomna and Rana (2007). The authors ob- served that women in various households in Niger and Lagos State Nigeria, could not give certain by-products such as the head and tails to their husbands to consume. According to the women, serving their husbands these by-products to consume may embarrass them owing to the ‘perceived societal expectations’, which saliently infer that consumption of certain parts of fish, indicate the poverty level of a person. The fact that more than 50% of the respondents consumed the skin, head and bone showed that these by-products were considered edible by many Nigerians. This can explain why ma- jority of the respondents did not regard the skin, head and bone as waste nor discard them as shown in Fig- ures 2 and 3 respectively. Jonsson and Vidarsson (2016) affirmed that dried cod heads in Iceland are mostly ex- ported to Nigeria. This is in agreement with the findings of this study where the head of fish was the second most consumed fish by-product among the respondents. The kind of fish species may also influence consum- ers’ attitude toward by-products. This may be the reason why few respondents agreed that the various by-prod- ucts (i.e. bone, head, gut, fins, gills and scales) may not always be consumed, discarded or regarded as waste. If the fish is of low value, it is also possible that its by-prod- ucts may not be regarded as valuable hence, may be dis- carded and/or regarded as waste. The hypothesis that the kind of fish species may play a role in determining the consumption and discard pattern of its by-products was affirmed by the findings of Falch et al. (2006) who reported that liver and roe from relatively large Cod (Gadus morhua) are the by-products utilized for human consumption in Northern Europe. According to Jonsson and Vidarsson (2016), Cod is the most important spe- cies in Iceland and its salted by-products, such as the tongues and cheeks from big cod heads are the most sought after in Southern Europe. Although the fish species consumed by the respon- dents was not correlated with their response on the by-products they regard as waste, discard and consume; the results in Figure 6 show that Atlantic Mackerel (a frozen fish locally called Titus) was the most consumed fish species followed by Catfish (Clarias gariepinus). The result is in agreement with the findings of Oluwaniyi and Dosumu (2009) who reported that Scomber scombrus (Atlantic Mackerel) and two other forms of frozen fish namely Clupea harengus (Herring) and Trachurus tra- churus (Horse Mackerel) were the most consumed and readily available marine fish species in South-Western Nigeria. Dauda et al. (2016) also reported that Atlantic Mackerel was the most preferred frozen fish in Kastina State, Nigeria. According to Oluwaniyi and Dosumu (2009) Atlantic mackerel being one of the most import- ed fish species in Nigeria; is one of the major sources of animal protein for the average individual and family in Nigeria because it is readily available and affordable. The reason for the lower consumption of Catfish when compared with Atlantic Mackerel may be because of its relatively high cost. This is in agreement with Oyewole and Amosu (2012) who observed that the consumption of Catfish in many parts of Nigeria was often regard- ed as a delicacy for the upper class. The texture of the by-products in each fish species may also contribute to whether their by-products can be consumed or not. This is in agreement with Oyewole and Amosu (2012) who observed that 47.1% of respondents in South-Western affirmed that the texture of Catfish (Clarias gariepinus) which they considered too soft and sometimes nauseat- ing made them averse to Catfish consumption. Accord- ing to Malde et al. (2010), bone structure in fish varies between species. The head and fins of Mackerel are soft thus can be chewed safely without the fear of the bones choking or wounding the buccal cavity of consumers. The soft texture of its by-products such as the head and bones may be the reason why more than 50% of the re- spondents in this study consume the head and bones. The Chi-square analysis of the socio-demographic characteristics of the respondents show that only sex, ed- ucation and income were found to be statistically signifi- cantly (P<0.05) related to the by-products respondents regarded as waste and those discarded. The Chi-square analysis in Table 2 show a statistically significant (P<0.05) relationship between the sex of respondents and certain by-products regarded as waste (gills, fins, gut, scales and bone) and those discarded (gills and fins). The results further indicated that the female respondents regarded the gills, fins, gut, scales and bone as waste when com- pared to the male respondents. The same pattern was also observed in their discard of gills and fins. In Nigeria, females are more directly involved in the preparation of 36 SQU Journal of Agricultural and Marine Sciences, 2022, Volume 27, Issue 2 Fish By-Products Consumption and Discard Pattern in Nigeria meals in the family and as a result, by-products which they do not consume or those they regard as waste may be discarded. If this happens, such by-products may never be consumed by other members of their house- hold. This may be the possible reason for the variation in responses between the male and female respondents. The findings from this study showed that education was the sole socio-demographic characteristic which was observed to have a statistically significant (P<0.05) relationship in the by-products (fins, skin and bone) consumed by the respondents. Respondent’s knowl- edge of the nutritional benefits of certain by-products may also have an influence on the by-products they consume. This may explain why the respondents who had a tertiary education consume the fins and bones more than those having lower educational degrees (as shown in Appendix 2). The positive relationship ob- served between education and the by-products con- sumed by the respondents implies that an improvement in the educational status of Nigerians on the health benefits of these by-products may lead to an increase in their consumption. This is in agreement with Dau- da et al. (2016) who observed a positive correlation be- tween education and fish demand among consumers. Income plays a role in shaping consumer’s food choices (Dauda et al. 2016). The result of the inferential statistics as shown in Table 2 indicate that there was a statistically significant (P<0.05) relationship between the respondents’ income and whether they discard and/or regard the fins as waste. In this study, it was surprising to note that a higher number of respondents who earned the least (Below ₦ 50, 000) regarded the fins as waste and discarded them when compared to respondents who earned above ₦ 50, 000. The findings in this study therefore contradicts those of Adeniyi et al. (2012) who reported that an increase in income, result in a shift of consumers preference towards more expensive sourc- es of animal protein. Consumer preference for certain by-products may be the reason why respondents with higher incomes (Above ₦50, 000) consumed the fins when compared with those with lower incomes. This is in agreement with Albert and Tasie (2016) who observed that the consumption of frozen fish among respondents in Rivers State, Nigeria, was solely dependent on their preference and not their income. Attitudes and prefer- ence are suggested to play a major role in explaining food consumption behavior in humans (Olsen, 2001). Food consumption pattern of humans is an extremely com- plex issue, and it varies significantly across countries, cultures, families, and individuals. It is influenced by many interrelating factors such as the food’s quality, sen- sory attributes, and availability; consumers preference, personality, knowledge (Olsen, 2004), social norms and socio-demographic characteristic of the respondents (Verbeke and Vackier, 2005). The result in this study indicates that several interrelating factors, such as so- cial factors, type of fish species and socio-demographic characteristics determine the by-products respondents in the study area regard as waste; discard and consume. Conclusion The results of this study have shown that the scales, gut, gills and fins are the by-products mostly discard- ed and underutilized in the three LGAs used in this study; while the skin, head and bones are the most consumed by-products. There is a need to educate the public on the benefits of utilizing these by-products to reduce the deleterious effects their discard will have on the environment. To prevent their discard, further re- search on ways these by-products can be developed into value-added products for both economic and en- vironmental benefits as well as for the realization of a sustainable circular economy is needed. 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Socio-demo- graphic characteristics Percentage responses (%) Percentage responses (%) It is not a waste It is not always a waste Yes, it is a waste I do not discard I do not always discard Yes, I discard SEX Head Male Female Gills Fins Gut Scales Skin Bone 72.4 77.2 13.3 12.4 14.3 9.4 12.2 4.0 9.2 2.0 87.8 92.1 50.0 59.9 17.3 10.9 16.3 4.0 13.3 5.9 17.3 9.9 5.1 3.0 7.1 4.5 30.6 16.3 10.2 11.9 70.4 83.7 72.4 84.7 70.4 86.1 85.7 95.0 5.1 3.5 19.4 23.8 66.3 70.8 5.1 6.9 7.1 7.4 1.0 1.5 1.0 3.5 85.7 93.1 41.8 54.5 15.3 12.9 15.3 5.9 15.3 4.5 11.2 8.9 3.1 1.0 10.2 4.0 33.7 21.8 18.4 16.3 79.6 87.1 77.6 88.1 87.8 89.6 95.9 95.5 4.1 3.0 24.5 23.8 Appendix 2: Percentage distribution of Socio-demographic characteristics (Education) and by-products consumed. Socio-demographic characteristics Percentage responses (%) I do not eat I do not always eat Yes, I eat Education Head SSCE and Others Tertiary Education Gills Fins Gut Scales Skin Bone 20.8 20.0 84.8 81.7 90.4 77.7 84.8 88.6 96.8 95.4 4.8 5.7 30.4 14.3 12.8 19.4 10.4 12.0 6.4 14.9 12.8 11.4 2.4 2.3 1.6 10.3 14.4 28.0 66.4 60.6 4.8 6.3 3.2 7.4 2.4 0.0 0.8 2.3 93.6 84.0 55.2 57.7 40 SQU Journal of Agricultural and Marine Sciences, 2022, Volume 27, Issue 2 Fish By-Products Consumption and Discard Pattern in Nigeria Appendix 3: Percentage distribution of Socio-demographic characteristics (Income) and by-products discarded and regarded as waste. Socio-demo- graphic characteristics Percentage responses (%) Percentage responses (%) It is not a waste It is not always a waste Yes, it is a waste I do not discard I do not always discard Yes, I discard Income Head Less than ₦ 20,000 ₦ 20,000–₦50,000 Above ₦ 50, 000 Gills Fins Gut Scales Skin Bone 79.2 77.8 70.5 17.7 11.1 9.5 8.3 10.1 14.3 8.3 5.1 6.7 0.0 7.1 5.7 88.5 93.9 89.5 60.4 54.5 55.2 10.4 13.1 15.2 6.3 7.1 10.5 2.1 9.1 13.3 13.5 12.1 11.4 3.1 2.0 5.7 5.2 5.1 5.7 17.7 22.2 22.9 10.4 9.1 14.3 76.0 81.8 80.0 89.6 80.8 72.4 78.1 82.8 81.9 96.9 90.9 88.6 6.3 1.0 4.8 21.9 23.2 21.9 75.0 72.7 61.0 6.3 6.1 6.7 6.3 5.1 10.5 3.1 0.0 1.0 1.0 2.0 4.8 91.7 90.9 89.5 53.1 48.5 49.5 9.4 13.1 18.1 12.5 7.1 7.6 3.1 7.1 13.3 10.4 10.1 8.6 2.1 3.0 0.0 5.2 7.1 5.7 25.0 25.3 26.7 15.6 14.1 21.0 81.3 86.9 85.7 90.6 87.9 76.2 86.5 89.9 90.5 96.9 94.9 95.2 3.1 2.0 4.8 21.9 26.3 23.8