Brazilian Sardine Research Articles

Biological patterns of reproduction of the Brazilian sardine Sardinella brasiliensis in the purse seine fishery of Southwest Atlantic Ocean: A long-term assessment

Recent estimates of the size at first maturity (L50) of Sardinella brasiliensis showed contradictory results with a decreasing in the fish stock biomass encompassed by increasing values of L50. The methodological approach used hereby allowed to separate sardines classified in the virginal maturity stage from those categorized in the recovery stage, and ready for one next spawning event. This study evaluated the hypothesis of the existence of separated stocks experiencing distinct environmental conditions and fishing pressures which may have altered L50 estimates using a robust dataset based on biological samples collected along the entire species distribution area in the southeast-south Brazilian coast [Rio de Janeiro (RJ), São Paulo (SP), Paraná (PR), Santa Catarina (SC) and Rio Grande do Sul (RS)] between 2000 and 2018. A reclassification of the gonadal maturity stages provided a more realistic estimate of L50. Combining biological, reproductive, fishing data and the mean temperature of the catch (MTC), the leave-one-out classification correctly re-assigned individuals with an overall accuracy of 85% [100% (RJ), 45% (SP), 99% (PR), 99% (SC) and 82% (RS)]. The connectivity between the local populations of S. brasiliensis off RJ (23°S) and the southern populations is limited, contrasting to spatial structured semi-discrete population-units found between SP and RS (24°S-30°S). The northern extreme population-unit (RJ, 22°S-23°S) showed an expressive reduction of L50, and a negative correlation was detected between the increasing MTC values and the abundance of early maturing individuals and recruits of the species. Stock specific L50 estimates seemed to act as indicators of long term environmental fluctuations.

Contribution of the nursery areas to the major fishing grounds of the Brazilian sardine (Sardinella brasiliensis) in Southeastern Brazilian Bight inferred from otolith fingerprints

In the late seventies, studies on the population structure of Sardinella brasiliensis suggested the existence of two stocks (23–25°S and 26°S−28°S) based on distinct regional somatic growth rates and spawning areas. This scenario was recently confirmed by using geochemical signatures of whole otoliths combined with basic biological data from two-year-old individuals collected in southeast-south Brazil. However, information about sardine movements and connectivity between their main juvenile recruitment areas and the adult fishing grounds is currently limited. In this work, otolith natal elemental fingerprints (core section) of recruits (age 0+) and adults (age 2+), collected respectively in the main spawning areas (2019) and fishing grounds (2021) were evaluate. Otolith geochemical signatures (element/Ca) of recruits were compared with those of adult fish from the same cohort to estimate connectivity between juvenile recruitment areas (Rio de Janeiro RJ: 22°S, São Paulo SP: 23°S and Santa Catarina SC: 26°S) and regional adult populations captured in the major fishing grounds (22–23°S, 24–25°S and 26–27°S). Uni and multi-elemental signatures showed significant differences for recruits and adult’s individuals. This variability was mainly driven by Ba/Ca, Cu/Ca and Mg/Ca ratios. Pairwise comparisons associated recruits and adults from the northern distribution area (RJ+SP), but differentiated them from those individual from south (SC). The leave-one-out matrix combining otolith fingerprints reassigned the individuals to their original areas with moderate to high accuracy, for both recruits (RJ: 79%, SP: 73% and SC: 67%) and adults (RJ: 75%, SP: 60% and SC: 69%). A multinomial logistic regression suggested that for the 2019 cohort the replenishment of adult populations of S. brasiliensis along the Southeastern Brazilian Bight was mostly derived from the northern recruitment area (RJ+SP=89%). Nonetheless, minor contribution from the southern counterparts to the northern stock was detected (11%), supporting the hypothesis of meta-population structure for this species.

Influence of salinity on growth and survival of juvenile Sardinella brasiliensis

The aim of the study was to evaluate the influence of changes in seawater salinity on juvenile Brazilian sardine (Sardinella brasiliensis). Through two assays, the LC50 (96 h) and the zootechnical performance (42 days) were determined, respectively. In the first assay, six treatments of salinity 0, 7, 14, 21, 28 and 35 parts per thousand (ppt) with three replicates were established. For this, 100-L cylinder-conical tanks were used, with 30 individuals with 45-day after eclosion (DAE) per unit, without water renewal and feeding. In the groups of salinity 0 and 7 ppt, all fish died on the first day. The LC50 was estimated at salinity 11.13 ppt. The second trial was designed with five treatments (salinity 7, 14, 21, 28 and 35 ppt), with three replicates. Two thousand-L cylindrical-conical tanks were used, with 30 individuals (58 DAE) per unit, with water renewal and feeding until apparent satiation. In the treatment salinity 7 ppt, all fish died by the second day. At salinity 35 ppt, the highest growth rates (2.78 g) and survival (100%) were observed. Salinity 14 ppt had the lowest survival (83%) and growth (1.48 g). We concluded that the juvenile sardines can be adapted to environments with salinity from 14 ppt, with significant losses. However, salinity 35 ppt showed the highest survival and growth rates.

Assessment of Human Health Risk of Metal(Loid) Content in Brazilian Sardine Along the Southwestern Atlantic.

The Brazilian sardine (Sardinella aurita) is an important food resource found in the subtropical Southwestern Atlantic Continental Shelf (CSSWA), but limited information about its metal(loid) concentrations is available, restricting effective risk assessment by its consumption. On this research, we hypothesized that S. aurita presents different metal(loid) concentrations within a latitudinal gradient in the CSSWA (northern and southern sectors). We also assessed the S. aurita consumption contamination risk in both sectors of the CSSWA. The results indicated that S. aurita might present different chemical and contamination profiles between the observed sectors, with highlights to As, Cr, and Fe at greater levels than the safety limits established by regulatory agencies. Such finds could be explained by urbanization, industrialization, continental and oceanographic processes along the CSSWA, corroborating our hypothesis for most observed metals(loid). On the other hand, our risk assessment analysis of metal(loid) concentrations did not indicate hazards for human consumption.

On the trophic role of pelagic fishes and fishery landings shifts in the South Brazil Bight

Knowledge of the feeding habits of pelagic fishes off the Brazilian coast is scarce, making the analysis of trophic interactions often inaccurate. Here, we investigated the diet and trophic role of 12 pelagic fish species by revisiting samples obtained by the ECOSAR II Program (FURG/IO/IBAMA) between 23°S and 28°40'S, an area also known as South Brazil Bight. In addition, we analyzed their biomass and fisheries landings in order to examine shifts over time. The content of 432 stomachs was analyzed at the lowest taxonomic level possible. The frequencies of occurrence were used to cluster species, revealing three trophic guilds: "Planktivorous Clupeiformes", "Planktivorous Carangiformes", and "Piscivores". Most Carangidae consumed mainly copepods and other small crustaceans, except Selene setapinnis which clustered in the piscivorous guild together with Scombriformes specimens. In terms of biomass, the dominance of Trachurus lathami, Sardinella brasiliensis, and Trichiurus lepturus was evident. The species' trophic levels ranged from 2.98 to 4.5, showing that these fishes occupied intermediate to high trophic position. Comparing fisheries landings in two study periods (1986-2002 and 2003-2019), six species showed a decrease, while three an increase. Correlations between landings of the Brazilian sardine (Sardinella brasiliensis) and other pelagic fishes indicate that when the former's decreases, the catch of alternative species, such as Opisthonema oglinum and Chloroscombrus chrysurus, increases. The intermediate position of small pelagics in the food web may affect the availability of commercial species by controlling the abundance of lower and upper trophic-level organisms. These findings fill essential gaps for ecosystem modeling, suggesting that ecosystembased fisheries management should address multispecies issues of the pelagic realm rather than only singlespecies approaches. Combining past survey data with yield trends provides evidence for both natural and humaninduced ocean changes.

Spatiotemporal Variability of the Catch Composition and Discards Estimates of the Different Methods of Onboard Preservation for the Brazilian Sardine Fishery in the Southwest Atlantic Ocean

Spatiotemporal Variability of the Catch Composition and Discards Estimates of the Different Methods of Onboard Preservation for the Brazilian Sardine Fishery in the Southwest Atlantic Ocean

Stock structure of the Brazilian sardine Sardinella brasiliensis from Southwest Atlantic Ocean inferred from otolith elemental signatures

The Brazilian sardine (Sardinella brasiliensis) supports the most important pelagic fishery in the southeast-south Brazil. The first studies on the population structure of S. brasiliensis suggested the existence of two stocks taking into account distinct regional somatic growth rates and spawning areas. However, subsequent works were unable to confirm this scenario, and at present for fisheries management purposes a single stock is considered in Brazil. In order to unravel the stock structure of S. brasiliensis, ninety adult individuals (two-year-old fish) were collected between February and October 2018 in three fishing grounds within its distribution area [Rio de Janeiro (RJ), Santa Catarina (SC) and Rio Grande do Sul (RS)]. Multi-elemental signatures of whole otoliths were determined using inductively coupled plasma mass spectrometry and combined with basic biological data (somatic condition, sex and gonadal developmental stages). A generalized linear model found somatic growth rates significantly different across regions. Whole otolith chemical signatures exhibited distinct regional patterns, mainly driven by differences in Ba/Ca, Cu/Ca, Li/Ca, Mg/Ca, Mn/Ca, Sr/Ca, and Zn/Ca. Combining somatic and reproductive data with multi-elemental signatures, the leave-one-out reclassification reassigned the individuals to their areas of origin with a high accuracy (100%, 93% and 87% for RJ, SC and RS, respectively). The results indicate a spatial isolation for the RJ individuals and some degree of intermixing between SC and RS. The data suggest that these fishing grounds should be considered as two stocks (RJ and SC+RS) for fisheries management purposes, although the southern stock is not necessarily homogeneous.

Population structure of the Brazilian sardine (Sardinella brasiliensis) in the Southwest Atlantic inferred from body morphology and otolith shape signatures

Population structure of the Brazilian sardine (Sardinella brasiliensis) in the Southwest Atlantic inferred from body morphology and otolith shape signatures

Live diet for first feeding of Brazilian sardine, Sardinella brasiliensis (STEINDACHNER, 1879), larvae in captivity

Previous studies indicate that Brazilian sardine can be produced in captivity as an alternative to fishing their overexploited stock. However, no research has been conducted about how to improve efficiency in larviculture, a bottleneck phase in aquaculture. Therefore, the aim of this study was to define the optimal live diet in the first feeding of Brazilian sardine larvae, testing five diets of (a) microalgae, (b) rotifer, (c) microalgae plus rotifer, (d) microalgae plus enriched rotifer and (e) microalgae plus wild zooplankton. After eight days, the larvae were sampled to verify survival, growth, digestive enzyme activities (lipase and alkaline protease) and RNA:DNA ratio. Separately, microalgae and rotifer were not enough to support the larvae, resulting in low survival (0% and 3.2 ± 2.9% respectively). However, when offered together they promoted higher survival (up to 40 ± 7.3%). Diets of rotifer enriched with oil emulsion or not produced similar growth (9.23 ± 0.16 mm and 9.13 ± 0.13 mm length respectively). The ingestion of microalgae plus zooplankton significantly increased larvae growth (10.26 ± 0.25 mm length and 2.49 ± 0.20 mg weight), lipase activity and RNA:DNA ratio after eight days. Therefore, the first feeding of Brazilian sardine larvae has better results when microalgae and zooplankton are offered together.

Unexpected diversity in the diet of Doryteuthis sanpaulensis (Brakoniecki, 1984) (Mollusca: Cephalopoda) from the southern Brazilian sardine fishery identified by metabarcoding

Growing fishing pressure worldwide has led to an increase in the exploitation of cephalopod products in fish markets where these taxa were not traditionally consumed. Squid catches have surged to meet that demand, yet for many species little is known about their role in food webs. Doryteuthis sanpaulensis is an important squid species in southeastern Brazilian fisheries. Despite many previous efforts at morphological analysis of its diet, few demersal and benthic species of fishes, crustaceans and mollusks have been identified to species level because the food is consumed in small digestible fragments. Here we used metabarcoding to analyze the diet of adult D. sanpaulensis caught as bycatch in the southern Brazilian sardine fishery. MOTUs generated from COI amplicons were assigned to taxa by matching against the NCBI nt database. Fishes constitute the majority of the diet of the analyzed samples. Considerable variability in the relative read abundance and frequency of occurrence of prey items across samples indicates the importance of increased sample sizes in analyses investigating ontogenetic, spatial, or temporal variation in diet. The results elucidate the rich diet of D. sanpaulensis off the Brazilian coast, and specifically that its varied diet includes more neritic diversity than previous studies have indicated.

Minimum rotifer density for best growth, survival and nutritional status of Brazilian sardine larvae, Sardinella brasiliensis

Live feed accounts for an important share of hatcheries costs and until now no study has examined how to reduce these costs in Brazilian sardine aquaculture. Therefore, this study verified and defined the minimum rotifer density in the first feeding of Brazilian sardine larvae that results in the best growth, survival, rotifer clearance and nutritional status (Lipase activity and RNA:DNA ratio). After initial exogenous feeding, six groups in triplicate were fed at 0.1, 1, 5, 10, 15 and 20 rotifer mL−1 during eight days. No residual rotifers were observed in the low-density treatments after the second day, which reduced by half larvae survival at 0.1 rotifer mL−1 (20 ± 2%) and mean growth by more than 20% when larvae were fed below 1 rotifer mL−1 (7.7 ± 0.1 mm length). On the other hand, densities above 5 rotifer mL−1 did not increase the RNA:DNA ratio (6.02–8.68) and decreased digestion efficiency at 15 and 20 rotifer mL−1, since lipase activity dropped by 30% to 3.79 U mg−1 of protein. Therefore, based on segmented regression, the breaking point that obtained maximum growth with the minimum requirement for rotifer ranged from 2.66 to 5.79 mL−1, or 266 to 579 rotifer larvae−1 per day.

SPONTANEOUS SPAWNING OF BRAZILIAN SARDINE IN CAPTIVITY

In one year, 76 first generation (F1) Brazilian sardine Sardinella brasiliensis breeders spawned 84 times spontaneously in captivity. This is the first report for the genus Sardinella. Following the pattern found in the natural environment, the number of spawns, as well as fertilization and hatching rates were higher in spring, summer and fall than in winter. Until now, winter spawning was only presumed to occur in a natural environment. Water temperature, and not photoperiod, was positively correlated with reproductive performance.

Etnoictiologia dos pescadores de seis comunidades caiçaras de Angra dos Reis-RJ

A Etnoictiologia, vertente das etnociências, vem sendo utilizada como ferramenta no manejo de estoques pesqueiros por fornecer informações sobre os aspectos biológicos e comportamentais de organismos marinhos. Os pescadores artesanais possuem um conhecimento ecológico tradicional sobre a maior parte das espécies que exploram, sendo capazes de opinar e sugerir alternativas para que a exploração do recurso se dê de forma sustentável, sendo assim o objetivo do presente trabalho é verificar o conhecimento dos pescadores de seis comunidades caiçaras de Angra dos Reis sobre variações nas abundâncias dos grupos de peixes por eles explorados. Os 28 pescadores participantes da pesquisa responderam um questionário socioeconômico e um questionário etnoictiológico. A partir dos resultados percebe-se que a pesca artesanal no local está entrando em declínio, devido à alta média de idade dos pescadores e ao descaso pela falta de investimento em infraestrutura na Baía da Ilha Grande. Os pescadores observaram principalmente a diminuição de corvina e sardinha-verdadeira, que vem sendo sobreexplorada pela pesca industrial, o que reflete na diminuição de cavalinha, xerelete/carapau e galo, que fazem parte de sua fauna acompanhante. Sendo assim, são necessárias alternativas de manejo pesqueiro, que priorizem não somente aspectos ecológicos, como também aspectos socioculturais dos pescadores artesanais.

Neutron Activation Analysis characterization procedures for fish consumed at São Paulo City

The characterization of edible tissues of fishes consumed by humans is very important for determination of several toxic and potentially toxic elements, ensuring the food safety. The Instrumental Neutron Activation Analysis (INAA) comparative method allows the determination of several of these elements, as well as others, for example of nutritional character. This study is part of an International Atomic Energy Agency (IAEA) technical cooperation project of Latin America and Caribbean countries to ensure the quality of food and biomonitoring of contaminants in shellfish and fishes. Ten specimens of 4 of the most consumed fish in São Paulo city: whitemouth croaker (Micropogonias Furnieri), smooth weakfish (Cynoscion learchus), common snook (Centropomus undecimalis) and Brazilian sardine (Sardinella brasiliensis) were analyzed. Complete procedures for analysis, which includes purchase in the largest warehouse in Latin America, transport to the laboratory, storage, freeze-drying, milling, weighting and others preparations of the subsamples, and the short irradiation parameters for the determination of Br, Cl, K, Mg, Mn and Na are reported. Results obtained under the same irradiation conditions for reference materials (oyster and mussel tissues) for macro and microelements are presented and are in agreement with their certificates, which indicate that the performed analyses were appropriate. Regarding to the mass fraction values obtained for the fish samples, they were in agreement with the literature.

Biological patterns of the Brazilian sardine in the purse seine fishery off Brazil

Biological patterns of the Brazilian sardine in the purse seine fishery off Brazil

Body and otolith shape analyses of the Brazilian sardine, Sardinella brasiliensis, to differentiate population-units in the purse seine fishery off Brazil

Body and otolith shape analyses of the Brazilian sardine, Sardinella brasiliensis, to differentiate population-units in the purse seine fishery off Brazil

Fishers' knowledge in Southeast Brazil: The case study of the Brazilian sardine

Fishers' local ecological knowledge (LEK) presents the enormous potential to assist in the conservation of depleted natural resources available to small-scale fisheries worldwide. Due to the significant socioeconomic value of sardines in the Southwestern Atlantic, the objective of this work was to register the LEK about Brazilian sardine of the traditional fishing village of Arraial do Cabo, Rio de Janeiro State, Brazil. Social science tools were used to extract data from biology, ecology, food taboos and human uses of Brazilian sardine. A qualitative analysis was performed through accurate coding and cross-checking using an emic-etic approach and all data made available was taken into consideration. Fishers highlighted information on areas of habitat, migration patterns, trophic ecology, and reproduction season. The LEK showed compliance with scientific literature in relevant points of the ecology and biology of this species which have a life the history that leads to increased vulnerability due to overfishing and management difficulties. We emphasize the importance of continuously sharing the LEK of the sardines between the community, researchers, and managers in favor of a more effective socio-ecological conservation of this fishing resource in Arraial do Cabo.

INVESTIGAÇÃO SOBRE fishing down marine food webs NO SUL DO BRASIL: IMPLICAÇÕES FINANCEIRAS E PARA A SUSTENTABILIDADE

O crescente desembarque pesqueiro de espécies de nível trófico baixo leva ao efeito fishing down food webs. O presente trabalho investiga se há sinais do efeito na pesca marinha no sul do Brasil entre os anos 1990 e 2007, e discute implicações financeiras e para a sustentabilidade da pesca. Consideraram-se peixes piscívoros os recursos de nível trófico ‘alto’ (P), e os de nível trófico ‘baixo’ os não piscívoros (NP). Compilaram-se informações sobre desembarques e valor de primeiro comércio. Constatou-se que na década de 1990 os desembarques de P eram permanentemente superiores apenas no Rio Grande do Sul, mas na década seguinte passaram a sê-lo também em São Paulo e Santa Catarina, contrário ao fishing down. Apesar de recursos P terem valor de comércio superior a NP, o valor financeiro dos desembarques (VDF) em dois estados caiu mais de 50%: em São Paulo, pela diminuição na safra de NP, como sardinha-verdadeira; e no Rio Grande do Sul, de P, como pescada-olhuda. Em Santa Catarina o VFD cresceu, por aumento nos desembarques de P, como bonito-listrado. Nessa pescaria o fishing down manifesta-se de forma indireta, preocupante, pelo significativo contingente de sardinha verdadeira capturada para uso como isca-viva.

Domestic landings and imports of seafood in emerging economies: The Brazilian sardines market

Seafood imports have increased strongly in emerging economies during the last decades. However, the impacts of increased imports on price determination process, local fishers' income and fish stocks have received limited attention. This paper presents a market integration and price transmission analysis for the Brazilian sardine market, comprising the fresh and canned sardines segments, to shed light on these issues. Imports currently supply about one-half the sardines in the Brazilian market, and even more when the domestic fishery landings are low. The results suggest not only a fully integrated market but also a complete price transmission in both sardine value chains. Hence, import competition with domestic fisheries limit price increases in the domestic fishery and reduce fishers' income and fishing effort. However, the canneries, consumers and fish stocks are better off.

Conserving Brazilian Sardine: Fisher’s attitudes and knowledge in the Marine Extractive Reserve of Arraial do Cabo, Rio de Janeiro State, Brazil

Due to the socioeconomic importance of sardines in the South Atlantic, the aim of this study was to evaluate the fishers’ LEK and the attitudes towards conservation of S. brasiliensis in the fishing village of the Arraial do Cabo, Rio de Janeiro, Brazil. A total of 134 semi-structured interviews were conducted from April to July 2016. The LEK was classified as moderate (0.56) as well as the conservation attitudes (0.60). It was shown that there was a correlation between LEK and income of fishers. There were differences in LEK and attitudes regarding conservation of sardines in all educational groups analyzed in the sampling population. The LEK and the attitudes also show significant association with boat ownership, occupation and if the fisherman belonged to the local fishing association. As a way to improve fishers’ attitudes in practice, we also encouraged the promotion of education among youth and adults is recommended so that the behavior of fishers becomes more favorable to the conservation of sardines in this fishing community. We also emphasize that local management must take into account the sociodemographic variables of fishers since these can influence LEK and their predisposition to conserve sardines. This approach would increase the likelihood of ensuring the efficient support of the local community in the conservation of this small pelagic fish.