Donna-Mareè Cawthorn

Fish species substitution and misnaming in South Africa: An economic, safety and sustainability conundrum revisited

While fish species mislabelling has emerged as a global problem, the tracking of improvements or deteriorations in seafood trading practices is challenging without a consistent basis for monitoring. The aim of this study was to develop a robust, repeatable species authentication protocol that could be used to benchmark the current and future incidences of fish mislabelling in South Africa. Using this approach, 149 fish samples collected from restaurants and retailers in three provinces (KwaZulu-Natal, Western Cape and Gauteng) were identified using DNA barcoding, supplemented in certain cases with mitochondrial control region sequencing. Overall, 18% of samples were incorrectly described in terms of species, with similar misrepresentation rates in restaurants (18%) and retail outlets (19%). While there appears to be some improvement in the transparency of local seafood marketing compared to previous studies, the results remain of concern and signal the need for enhanced seafood labelling regulations, monitoring and law enforcement.

Establishment of a mitochondrial DNA sequence database for the identification of fish species commercially available in South Africa

The limitations intrinsic to morphology‐based identification systems have created an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species, particularly those that are prone to overexploitation and/or market substitution. The aim of this study was to develop a comprehensive reference library of DNA sequence data to allow the explicit identification of 53 commercially available fish species in South Africa, most of which were locally caught marine species. Sequences of approximately 655 base pairs were generated for all species from the cytochrome c oxidase I (COI) gene, the region widely adopted for DNA barcoding. Specimens of the genus Thunnus were examined in further detail, employing additional mitochondrial DNA control region sequencing. Cumulative analysis of the sequences from the COI region revealed mean conspecific, congeneric and confamilial Kimura 2‐parameter distances of 0.10%, 4.58% and 15.43%, respectively. The results showed that the vast majority (98%) of fish species examined could be readily differentiated by their COI barcodes, but that supplementary control region sequencing was more useful for the discrimination of three Thunnus species. Additionally, the analysis of COI data raised the prospect that Thyrsites atun (snoek) could constitute a species pair. The present study has established the necessary genetic information to permit the unambiguous identification of 53 commonly marketed fish species in South Africa, the applications of which hold a plethora of benefits relating to ecology research, fisheries management and control of commercial practices.

The bushmeat and food security nexus: A global account of the contributions, conundrums and ethical collisions

Abstract Wild meat or ‘bushmeat’ has long served as a principal source of protein and a key contributor to the food security of millions of people across the developing world, most notably in Africa, Latin America and Asia. More recently, however, growing human populations, technological elaborations and the emergence of a booming commercial bushmeat trade have culminated in unprecedented harvest rates and the consequent decline of numerous wildlife populations. Most research efforts aimed at tackling this problem to date have been rooted in the biological disciplines, focused on quantifying the trade and measuring its level of destruction on wildlife and ecosystems. Comparatively little effort, on the other hand, has been expended on illuminating the role of bushmeat in human livelihoods and in providing alternative sources of food and income, as well as the infrastructure to make these feasible. This paper aims to shift the focus to the human dimension, emphasising the true contributions of bushmeat to food security, nutrition and well-being, while balancing this perspective by considering the far-reaching impacts of overexploitation. What emerges from this synthesis is that bushmeat management will ultimately depend on understanding and working with people, with any approaches focused too narrowly on biodiversity preservation running the risk of failure in the long term. If wildlife is to survive and be utilised in the future, there is undoubtedly a need to relax adherence to unswerving biocentric or anthropocentric convictions, to appreciate the necessity for certain trade-offs and to develop integrated and flexible approaches that reconcile the requirements of both the animals and the people.

The effects of gender, size and life-cycle stage on the chemical composition of smoothhound shark (Mustelus mustelus) meat

BACKGROUND Knowledge on the chemical composition of foods, and on the variation in such components as influenced by endogenous factors, is required for nutritional labelling, dietetic planning and food processing. This study examined the effects of endogenous factors (gender, size and life-cycle stage) on the chemical components (proximate, amino acid, fatty acid, mineral and mercury contents) of smoothhound shark (Mustelus mustelus) meat. RESULTS Levels of moisture, protein, lipids, ash, amino acids and most minerals were not affected (P > 0.05) by the gender, size or life-cycle stages of the sharks. The fatty acid content was higher in females than in males, as well as in non-pregnant females compared to pregnant females. Certain fatty acids decreased in quantity in medium-sized sharks (prior to maturity). Pregnant females had higher aluminium (Al) and copper (Cu) levels than non-pregnant females and mercury (Hg) levels were highest in large male sharks. CONCLUSION This study has, for the first time, established that endogenous factors have minimal influence on the chemical composition of M. mustelus meat, demonstrating the feasibility of describing an average composition for this species. Additionally, new insights have been obtained on potential safety concerns (mercury) associated with consumption of the meat that require further investigation.

SPECIES OF MEAT ANIMALS | Game and Exotic Animals

An overview is presented describing the characteristics of the meat (game and venison) obtained from various land animals and birds that are not conventionally considered domesticated. The species discussed include those derived from wild harvesting or farming, such as game birds, deer, antelope, kangaroos, rabbits, and wild Suid species, as well as camelids, buffalo, and bison. Physical and chemical meat quality attributes are considered, focusing on carcass characteristics, meat composition, and sensory aspects. Particular emphasis is placed on the meat’s nutritional value, as well as its potential to contribute to food security and the health of a growing population.

Physical quality attributes of male and female wild fallow deer (Dama dama) muscles

Physical meat quality measurements were conducted on the longissimus thoracis et lumborum, biceps femoris, semimembranosus, semitendinosus, infraspinatus and supraspinatus muscles from male (n=6) and female (n=6) fallow deer (Dama dama) harvested in South Africa. Ultimate pH (pHu), drip loss, cooking loss and shear force values were influenced (p≤0.05) by muscle, but not gender. Mean pHu readings were 5.4-5.6 in the muscles with the two forequarter muscles having the highest readings, while drip loss, cooking loss and shear force values ranged from 1.3-1.6%, 29.4-36.1% and 31.3-61.9N, respectively. Muscle, however, had an effect (p≤0.05) on all the measured colour parameters (L*, a*, b*, chroma, hue angle), whereas gender only influenced (p≤0.05) the a* and chroma values in certain muscles. It can be concluded that the physical meat quality attributes of the fallow deer muscles compare favourably with that from other game species commonly consumed in South Africa.

Proximate and fatty acid composition of zebra (Equus quagga burchellii) muscle and subcutaneous fat

BACKGROUND The meat from African game species is healthy, naturally produced and increasingly popular with consumers. Among these species, zebra (Equus quagga burchellii) are growing in number in South Africa, with the meat from surplus animals holding potential to contribute to food security and economic stability. Despite being consumed locally and globally, little information exists on the composition of zebra meat. This study aimed to determine the proximate composition of zebra meat as well as the fatty acid composition of the intramuscular (IMF) and subcutaneous (SCF) fat. RESULTS Zebra longissimus lumborum muscle was shown to have a high mean protein content (22.29 g per 100 g) and low mean fat content (1.47 g per 100 g). High proportions of polyunsaturated fatty acids (PUFAs) were found in the IMF (41.15%) and SCF (37.71%), mainly comprising α-linolenic (C18:3n-3) and linoleic (C18:2n-6) acids. Furthermore, the IMF and SCF had favourable PUFA/saturated fatty acid ratios (>0.4) and omega-6/omega-3 ratios (<4), indicating that both components are healthy lipid food sources. CONCLUSION This study has shed new light on the nutritional value of zebra meat, which will not only be important for food product labelling, nutritional education and incorporation into food composition databases, but will also be indispensable for marketing and export purposes.

MEAT, ANIMAL, POULTRY AND FISH PRODUCTION AND MANAGEMENT | Exotic and other Species

An overview is presented describing the human usage of exotic animal species (including birds, buffalo, camels, deer, game animals, goats, rabbits, rodents, reptiles, kangaroos, and yaks) around the world, which are derived either from wild harvesting or farming. The production systems are discussed with particular emphasis on the challenges and opportunities arising from the commercial use of exotic species, the products produced for subsistence or for financial gain, and the problems faced with overexploitation of certain species.