Utilization of the jellyfish occuring in the bycatch for human consumption in the south of Brazil CARLA CAMILA BAZI, MARCUS PESSATTI & CHARRID RESGALLA JUNIOR* School of the Sea, Science and Technology, Universidade do Vale do Itajaí (UNIVALI), C.P. 360, Itajaí, Santa Catarina, 88.302-901, Brazil * Corresponding author: [email protected] Abstract. With the increase in reports of the occurrence of jellyfish and the recent discoveries about their potential use in the areas of healthcare, biotechnology, and nutrition, this work tested a salt processing protocol for jellyfish caught off the Santa Catarina coast, in the south of Brazil, in an attempt to produce a unique product with nutritional value. The jellyfish were captured in bottom trawling artisanal shrimp fishing nets, and a mixed salt process was applied using a mixture of salts in six stages of dehydration. The most frequently occurring and potentially useful species for human consumption in the bycatch were Rhacostoma atlanticum, Chiropsalmus quadrumanus, and Lychnorhiza lucerna. The mean percentage yield values (salted weight/wet weight) of 10.6% for C. quadrumanus, 6.6% for L. lucerna, and 1.7% for R. atlanticum. The results of microbiological tests on the salted material were negative and the percentage of weight gain following rehydration was greater than 95% in all cases. The salting process for the three species was adapted to be started on board and completed in 21 days on land, generating a final product with color and odor characteristics that meet the standards found in the market. Key words: jellyfish, food, salting, bromatology Resumo: Utilização de medusas ocorrentes na pesca acidental para consumo humano no sul do Brasil. Com o aumento dos relatos da ocorrência de águas-vivas e as recentes descobertas sobre seu potencial de uso nas áreas de saúde, biotecnologia e nutrição, este trabalho testou um protocolo de processamento de salga para águas-vivas capturadas no litoral catarinense, sul do Brasil, na tentativa de produzir um produto único com valor nutricional. As águas-vivas foram capturadas em redes de pesca de camarão artesanal de arrasto pelo fundo, e um processo de salga mista foi aplicado usando uma mistura de sais em seis estágios de desidratação. As espécies mais frequentes e potencialmente mais úteis para o consumo humano nas capturas acessórias foram Rhacostoma atlanticum, Chiropsalmus quadrumanus e Lychnorhiza lucerna. Os valores médios do percentual de rendimento (peso salgado/peso úmido) foram 10,6% para C. quadrumanus, 6,6% para L. lucerna e 1,7% para R. atlanticum. Os resultados dos testes microbiológicos no material salgado foram negativos e o percentual de ganho de peso após a reidratação foi superior a 95% em todos os casos. O processo de salga das três espécies foi adaptado para ser iniciado a bordo e concluído em 21 dias em terra, gerando um produto final com características de cor e odor que atendem aos padrões encontrados no mercado. Palavras-chave: Medusa, Alimento, Salga, Bromatologia. Introduction 2010, Morandini et al. 2005, Resgalla Jr et al. 2005, Due to the potential for stings, large medusae 2011, Nogueira Jr. 2006). They are also avoided by are avoided by bathers and divers (Haddad et al. fishermen, as they interfere in the fishing (Nagata et Pan-American Journal of Aquatic Sciences (2019), 14(1): 13-23 14 C. C. BAZI ET AL. al. 2009). On the other hand, it is recognized that salting (Sloan & Gunn 1985, Huang 1988) in these organisms make a significant ecological basically the same way as for fish, such as sardines contribution to the carbon cycle of the oceans and cod. This type of processing promotes the (Graham et al. 2014), mainly due to the mortality of extraction of water from the tissues of the animal, the organisms after episodes of occurrence in high inhibits the growth of microorganisms, and increases densities (Sweetman et al., 2016). shelf-life. At the same time, the characteristics of The occurrence of high densities of gelatinous palatability, such as consistency, a slight organisms, known as blooms, have been correlated crunchiness, and a pleasant color are preserved with favorable conditions in the marine environment (Hsieh & Rudloe 1994, Hsieh et al. 2001). or intrinsic biological characteristics of each group Due to the great occurrence of jellyfish in (Lucas & Dawson 2014). These phenomena have artisanal shrimp fishing along the Santa Catarina been occurring frequently, and may be associated coast, in the south of Brazil, the feasibility of the with global warming, changes to the marine salting protocol technique applied to different environment from pollution, and overfishing of their jellyfish species was investigated, and the definite main predators and competitors (Mills 2001, Purcell nutritional value of the product, as demonstrated by et al. 2007, Condon et al. 2012). Recent studies bromatological analyses, indicated an alternative for show the occurrence of increasingly intense blooms the use of certain jellyfish species within the fishing along the coasts of the countries of Oceania production chain. (Richardson et al. 2009), East Asia (Dong et al. 2010), and in the Mediterranean Sea (Boero, 2013, Material and Methods Purcell et al. 2001). Collection: Sampling campaigns for the collection However, in Brazil, little is known about the of jellyfish were conducted monthly, from February abundance pattern of these organisms. In a study 2012 to January 2016, on the northern coast of Santa conducted on the southern coast of Brazil, Schereder Catarina and in the region around the mouth of the et al. (2014) measured the density of animals caught Itajaí-açu River, between the 10 to 20 m isobaths as bycatch in the fishing nets of the commercial and 25 km off the coast (26°45’ to 27°00’ S) (Fig. 1). fleet. The authors identified that the jellyfish with 49 o 26 o Itaj aí- açu ri ver o 27 28 o the highest frequency and number, especially in 29 o spring and summer, was the hydromedusa Rhacostoma atlanticum. Because of it high biomass, organisms of this species have become a problem for fishermen, since in warmer seasons fishing is greatly hampered by the large volume occupied by the jellyfish in the trawling nets, increasing the fishing time of the boats and consequently reducing income. On the other hand, the knowledge of the potential use of these organisms for commercial purposes, and the utilization of the bycatch, is still in its early stages. The capture and processing of jellyfish for human consumption have been developed in Asian countries for more than 1700 years (Li & Hsieh 2004, Martínez & Tello 2013). Because it is considered to be a delicacy, jellyfish production has already been commercialized in those countries, as is the case of the species Rhopilema esculentum, which is farming in China (You et al. 2007). Recently, countries of North and South America, particularly the USA and Mexico, have begun to invest in the capture and processing of these Figure 1 - Coast of Santa Catarina and shrimp artisanal fishing area (marked area) used to obtain macromedusae products, but this exploration is far more intense in specimens. Asian countries (Brotz et al., 2016). The processing of medusa jellyfish as food is carried out mainly by Pan-American Journal of Aquatic Sciences (2019), 14(1): 13-23 Use of bycatch jellyfish 15 The bottom trawls were performed from a Protein, mineral residue, and aluminum content: motorized boat, using nets with a mesh size of 50 The chemical analyses were performed according to mm between opposite knots in the body and 30 mm Horwitz (2000). The total crude protein analysis was in the bagger, with a length of 14 meters and performed using an adaptation of the protocol of opening of 5 meters. Surface temperature and Galvani & Gaertner (2006). To the procedure was salinity data were obtained using a YSI 30 thermo- used 50 mg of the dry sample and 500 mg of salinometer. For the salting process, 22 sampling catalyzer (Na2SO4 and CuSO4.5H2O), which was campaigns were conducted to collect organisms digested in 2 mL of sulfuric acid in a block digestor during the study period, 9 of which gathered enough at 350 ºC for about 3 hours, until the color change. organisms to perform the salting process. The After digestion, distillation was performed, adding 6 jellyfish obtained in the trawls were bagged on mL of distilled water to the digested sample. The board and transported to the laboratory, where they sample was neutralized in the distiller with NaOH at were washed in running water and sent to the salt 8 M and the receiver solution was composed of 25 processing. To estimate the density of the species mL of boric acid at 4% and universal coloring. captured, the data were standardized by number of Finally, the receiver solution was titrated with HCl at organisms per 10 minutes of bottom trawling. 0.05 N and the protein content calculated, Salting: The protocol used for jellyfish processing considering 6.25 as the nitrogen conversion factor was that proposed by Sloan & Gunn (1985), with for protein. To determine the mineral residue modifications in an attempt to initiate the processing content, the hydrated (desalted) jellyfish samples on board, eliminating the problem of having to land were dried at a constant weight in a heating chamber immediately after the catch, since jellyfish cannot be at 105°C and incinerated in a muffle oven at 550ºC kept on ice prior to processing (steps I-VI, Table I). for 2 hours. The mineral residue content was defined For this reason, the first 24 hours of the protocol as the difference between the weight of the dry were conducted in sea water. In this procedure, a sample before incineration and the weight of the mixture of sodium chloride, potassium alum, and sample after incineration.