Sampling is the act, process, or technique of selecting a suitable sample, or a representative part of a population for the purpose of determining parameters or characteristics of the whole population (Mugo, 2004). Samples of the groups targeted were obtained instead of a complete enumeration (census) for many reasons, it is cheaper to observe a part rather than the whole (though careful consideration was taken to the dangers of using samples), timelines, the large size of many groups targeted, inaccessibility of some of the groups, destructiveness of the observation and accuracy (Mugo, 2004). To draw conclusions about groups from samples, inferential statistics were used, which enable to determine a population’s characteristics by directly observing only a portion (or sample) of the population.
Determination of sample size should take into consideration several factors; i.e. type of research, research hypotheses, financial constraints, the importance of the results, the number of variable studies, the method of data collection, and the degree of accuracy needed (Dillon and Hardaker, 1993; Malhotra, 1999; McMillan, and Schumacher, 1989).
For this study, the sample size was defined using a mix of judgemental and snowball sampling techniques8, as the research aimed to target those individuals with the most dynamic role (as described previously) within the tilapia industry. The approx number of institutions/businesses for each group targeted by the study and the number of individuals sampled for each group are summarised in Table 2.3. The size of the sample selected for each group targeted by the study was defined as follows:
Farmers
The regions and businesses targeted by the study were defined according to the information gathered from secondary data and cross-checked with data gathered from the first stage of the field work, which included the feedback of governmental institutions, local associations, input suppliers, NGOs and farmers. As the aim of the research was to apprise the trade of farmed tilapia products in Mexico, commercial operations were particularly targeted in the study.
Table 2.3 Number of individuals/businesses/institutions sampled in the study per marketing sector.
8
Judgemental sampling is a form of convenience non-probability sampling technique in which the population elements are purposively selected based on the judgement of the researcher. While snowball sampling selects an initial group of respondents randomly, and subsequent respondents are selected based on referrals or information provided by the initial respondents. This process might be carried out in waves by obtaining referrals from referrals (Malhotra, 1999; McCrossan, 1984; Mugo, 2004).
Sector/Group Population Sample size Farmers 801* 72** Fishermen 196,481 24 Middlemen n/a 10 Importers n/a 6 Processor 346 3 Wholesalers 365 36 Supermarkets 2,590 8*** Fishmongers 6,558 35 Caterers 31,902 32
Policy Makers n/a 28
Financing Institutions n/a 12
Input Suppliers 507 14
Other Groups n/a 30
Total 310
* Data provided only by some states and included producers from the social sector. ** 32 Hatcheries and 40 ongrowing
*** Head offices
The research covered 72 commercial farms (32 hatcheries and 40 complete-cycle or on- growing farms); were businesses with productions and trade above 1 t yr-1 were considered, as below that commonly resulted in operators practicing tilapia farming for subsistence purposes only with little or no trade intended. Moreover, due to the large size of the country, the study covered those operations located within the main producing regions. As an agri-business and due to the particular requirements of the species, commercial tilapia farms were normally located within rural tropical and sub-tropical regions of the country (below the tropic of Cancer) (Morales, 1991). Thus, individuals targeted by the study were mostly located within central and southern states of the country, including the states of Sinaloa, Nayarit, San Luis Potosi, Guanjuato, Tamaulipas, Jalisco, Colima, Michoacan, Veracruz, Tabasco, Chiapas, Campeche, Yucatan and Quintana Roo.
Additionally, the research also includes description of successful case studies in Mexico, highlighting their businesses organisation (integration9, partnerships10, and diversification11) and their strategies.
Fishermen
The states with the largest productions and their respective fisheries were the main target for assessment of the catching sector; which included the interview of 24 fishermen from the main fisheries / fishing associations (i.e. El Infiernillo, Temascal, Aguamilpa, La Angostura and El Salto), with trading volumes of approx 20 t yr-1. Selection of individuals was cross-checked with information provided from middlemen.
Middlemen
The study focused on the most representative businesses from major fisheries (i.e. El Infiernillo, Temascal, Aguamilpa, La Angostura y El Salto), normally trading more than 100 t yr-1 of tilapia products. The study included 10 middlemen in the study, located mainly in nearby populations to the source (major tilapia fisheries). Individuals were selected through cross-checked information gathered from fishermen and wholesalers, as official figures were unavailable.
9 Can be described as horizontal and vertical integration, in the former businesses merge or acquire other business within the same level of the marketing chain (Clemente et al., 2001), whereas in the latter the firm owns all or part of its upstream suppliers and its downstream buyers (Greaver II, 1998).
10 A partnership is the relationship existing between two or more persons who join to carry on a trade or business. Each person contributes money, property, labour, or skill, and expects to share in the profits and losses of the business (IRS, 2006).
11 Business diversification seeks to increase profitability through greater sales volume obtained from new products and/or new markets (Hutt et al., 2003; Singh et al., 2001).
Importers
The study included 6 major importers, with trading volumes above 500 t yr-1. Businesses were mostly based on major bordering cities in the north (i.e. Tijuana, Ensenada, and Reynosa), large cities (i.e. Mexico City, Guadalajara and Monterrey) and merchant ports (i.e. Mansanillo and Mazatlan) (F. Jaimes-Cantu, Importer, personal communication, 4 November, 2003). The selection of individuals depended on cross-checked information from wholesalers, supermarkets and fishmongers; as no official figures were available for this particular sector.
Processors
In contrast to the large number of seafood processing businesses available in the country, at the time of the study, there were only three industrial processing plants (i.e. registered and certified) producing tilapia products: Barol (Hermosillo, Sonora), Pisimex (Tomatlan, Jalisco) and Pescados de Michoacan (Patzcuaro, Michoacan), which were included in the research (J. Lara-Zumaya and J.R. Calderon-Chavez, processors, personal communication, November/December, 2003).
Wholesalers
Due to the large number of businesses and their wide distribution, the research focused on targeting those businesses located within major wholesaling centres (i.e. “La Nueva Viga”, Mexico City; “Mercado del Mar”, Guadalajara; and Seafood Wholesalers in Monterrey. The study covered 36 businesses wholesaling businesses, with trading volumes above 100 t yr-1.
Supermarkets
Out of the 42 supermarket chains registered in Mexico, 8 highlighted for their trade in seafood products, i.e. Wal-Mart, Gigante, Comercial Mexicana, Soriana, Chedraui, Casa Ley, HEB, Carrefour (Sanchez, 2003). Commonly these corporations had collection centres (typically located in Mexico City, Guadalajara and Monterrey) were products were
re-distributed to their outlets. The research targeted these collection centres due to its practicality and representative on the corporation’s views on the research issues.
Fishmongers
Fishmongers were found all over the country. For effect of practicality, the research targeted 35 businesses located in major cities of regions were tilapia is most consumed, i.e. Mexico City, Guadalajara, Culiacan, Colima, Veracruz, Tabasco and Campeche (J. Reyes, FIRA Financer, personal communication, 10 October, 2003).
Caterers
Caterers were represented mainly by restaurants. Similar to fishmongers, the businesses offering tilapia were located within major cities within the centre and south of the country. Thus the study included 32 businesses located within the same areas. Individuals were selected through cross-checked information gathered from producers and wholesalers, as official figures of businesses trading tilapia products were unavailable.
Other institutions/businesses related to the tilapia industry
The study included 28 policy and regulatory institutions and 12 financing organisations. Most of these organisations/institutions were located in Mexico City or the capital of each state. The individuals targeted were located in major producing and trading regions (centre and south of the country), and selected through cross-checked information gathered from producers, traders, and other institutions.
Input suppliers and other businesses related to the industry were also targeted in the study, which included 14 businesses for the former and 30 individuals for the later. Most of these businesses/individuals were located within producing areas, and selected through cross- checked information gathered from producers, traders and other businesses/institutions related to the industry.