Argentine Anchovy Research Articles

What are you eating? A stable isotope insight into the trophic ecology of short-beaked common dolphins in the Southwestern Atlantic Ocean

As the feeding habits of marine mammals are particularly difficult to observe, stable isotope analysis has become an essential tool to investigate several aspects of dolphin's trophic ecology. Short-beaked common dolphins (Delphinus delphis) occur off Argentina coastline from 36°S to 42°S, but nothing is known about latitudinal changes in diet. A stable isotope analysis has been performed on three short-beaked common dolphins groups: Buenos Aires group (n=20), Golfo San Matías inshore group (n=24), and Golfo San Matías offshore group (n=16). Highly significant differences in average δ15Nskin values were found among the three groups of dolphins considered. Differences were also statistically significant for the average δ13Cskin and Suess corrected δ13Cskin values. Furthermore, no significant differences were found in the δ13Cskin values of the dolphins from the inshore group sampled during summer and winter seasons at Golfo San Matías, although the δ15Nskin values changes seasonally, suggesting that probably dolphins forage at a higher trophic level in summer. The SIAR model indicated that juvenile Argentine hake (Merluccius hubbsi) had the highest mean feasible contribution to the diet of short-beaked common dolphins inhabiting the continental shelf off Buenos Aires and northern Patagonia, whereas the Argentine anchovy (Engraulis anchoita) did it for short-beaked common dolphins inhabiting the Golfo San Matías The results obtained in this study increase the knowledge of trophic ecology for high trophic level predators such as short-beaked common dolphins along the Argentina coast in support of effective conservation and management programs.

Assessment of the labelling accuracy of spanish semipreserved anchovies products by FINS (forensically informative nucleotide sequencing).

Anchovies have been traditionally captured and processed for human consumption for millennia. In the case of Spain, ripened and salted anchovies are a delicacy, which, in some cases, can reach high commercial values. Although there have been a number of studies presenting DNA methodologies for the identification of anchovies, this is one of the first studies investigating the level of mislabelling in this kind of products in Europe. Sixty-three commercial semipreserved anchovy products were collected in different types of food markets in four Spanish cities to check labelling accuracy. Species determination in these commercial products was performed by sequencing two different cyt-b mitochondrial DNA fragments. Results revealed mislabelling levels higher than 15%, what authors consider relatively high considering the importance of the product. The most frequent substitute species was the Argentine anchovy, Engraulis anchoita, which can be interpreted as an economic fraud.

Physicochemical and Functional Properties of Protein Recovered from Fish Waste

ABSTRACTThis work aimed to evaluate the physicochemical and functional properties of proteins recovered from whitemouth croaker (Micropogonias furnieri) and Argentine anchovy (Engraulis anchoita) residues obtained by the process of acid solubilization using HCl at pH = 2 and alkaline solubilization using NaOH at pH = 12 and isoelectric precipitation (pH = 5.5). The proximate composition and functional properties were determined. The solubilization and water holding capacity (WHC) of the recovered protein were studied in the pH range of 3, 5, 7, 9, and 11. The high protein content and lowest lipid reduction presented by the protein recovered from the whitemouth croaker residue and obtained by the acid solubilizing process was 97.1 and 98.4%, respectively. The maximum solubilized protein was at pH 3 and 11, and the minimum solubilized protein was at pH 5 for both species. The greater ability to retain oil was observed for the alkaline solubilization process (8.3 and 7.3). The lower WHC was at pH 5. The acid and alkali residue concentrates of the whitemouth croaker presented higher WHC at pH 3 and 11. These proteins can be used in preparing edible films and have been used to produce bioactive compounds for supplements or functional ingredients.

Relationships between environmental features, distribution and abundance of the Argentine anchovy, Engraulis anchoita, on the South West Atlantic Continental Shelf

Marine fisheries in Brazil follow a similar trend as the rest of the world, with reduced catches of most stocks. Although extensive, the Brazilian coast is poorly assessed, and marine fishery resources are not properly managed. Small pelagic fishes are secondary consumers, which feed on zooplankton and serve as foraging species for large, carnivorous fishes. The anchovy (Engraulis anchoita) is an abundant, small pelagic fish found in abundance in Brazilian waters as it migrates along the Brazilian, Uruguayan and Argentine shelves. In 2010, five acoustic assessment cruises were conducted to estimate anchovy biomass in the southernmost part of the Brazilian coast. Hydroacoustic data were obtained using a SIMRAD EK 500 echo sounder along parallel transects. CTD (conductivity temperature depth) casts and mid-water trawl hauls were used to collect environmental and biological data. Anchovy biomass was estimated using NASC values, the fish target strength by size and the dimension of the surveyed area. For each survey, a GLM binomial was fitted to anchovy presence and the following explanatory variables: surface salinity and temperature, bottom salinity and temperature, and depth. Anchovy biomass ranged between 73,000 (June) and 814,000 (August) tons. We observed a mean temperature decrease of ∼3°C during the June and August surveys. This sharp environmental change was followed by a distinct increase in adult anchovy biomass from the first to the second survey. Fitted GLM models indicated that the bottom layers of cold, saline water had a positive effect on anchovy presence in August but not in June. Furthermore, during the August survey, a sharp change in the surface layer waters was observed on the Southern Brazilian Shelf, as the result of a low-salinity water inflow to this area. This phenomena was due to the Patos Lagoon runoff and also to the coastal winds over the Argentine Shelf, which forces the northward spreading of the Plate River plume to lower latitudes. This inflow increases primary productivity and, subsequently, the occurrence of fishes within the area.

New methods for impact assessment of biotic-resource depletion in life cycle assessment of fisheries: theory and application

It is difficult to address all of the direct environmental impacts of fisheries using conventional methods of Life Cycle Assessment (LCA). A methodological framework was developed that calculates regionalised characterisation factors for biomass uptake by fishing activities to assess impacts of biotic-resource depletion at both species and ecosystem levels. These two levels were studied to include effects of catch on the collapse of a particular stock of a given species and on total biomass availability in oceans. Characterisation factors were calculated for 127 fish species and 88 marine provinces. The compatibility of this method with other frameworks is discussed, as well as the methodological limitations. The method was applied to two contrasting examples from fisheries (Northern Atlantic albacore tuna and Northern Argentine anchovy). The impacts of one tonne of tuna on biotic natural resources were 4 and 14 times as high as those of anchovy at the ecosystem and species levels, respectively. The application demonstrates that the method is relevant, as it addresses a topic of global interest and fills a gap in LCA impact assessment to contrast impacts of removals of different fish species in terms of biotic natural resource depletion.

Argentine anchovy (Engraulis anchoita) stock identification and incipient exploitation in southern Brazil

The Argentine anchovy (Engraulis anchoita) is an essential species in the pelagic ecosystem of the southwest Atlantic Ocean, and a potentially important fishery resource. Exploitation has recently started in southern Brazil, so it requires a better understanding of their structure and population dynamics. This work aims to update the information on the population identification of E. anchoita. Parameters such as age and size composition, length-at-age data and other parameters using sagittae otoliths were used to compare anchovy of the continental shelf between 20o and 32oS. The results indicate the existence of different populations in the southeastern and southern regions of Brazil: the bonaerense stock in southern Brazil is shared with Argentina and Uruguay and exhibits migratory behavior, while in the southeast there is a population confined to this region and shows different population characteristics. This has implications for the management of this species and should be taken into account by the institutions responsible for the assessment and management of fisheries in Brazil.

Physical, mechanical and antimicrobial properties of Argentine anchovy (Engraulis anchoita) protein films incorporated with organic acids

Physical, mechanical and antimicrobial properties of protein films from Argentine anchovy (Engraulis anchoita) incorporated with 0, 0.50, 0.75 and 1.50% sorbic or benzoic acids were investigated against Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Enteritidis and Staphylococcus aureus. The effects of films containing 1.50% sorbic or benzoic acids were tested on meat inoculated with Escherichia coli O157:H7 and Listeria monocytogenes during storage at 5 °C. The increased concentration from 0.50 to 1.50% of sorbic and benzoic acids resulted in decreased tensile strength and increased elongation at break, color difference, opacity, water vapor permeability and solubility. Scanning electron microscopic images of the control film revealed a homogeneous and continuous structure and the presence of micropores on the film surface containing 1.50% of sorbic or benzoic acids, which contributed to the physical and mechanical properties of the resulting films. The control films did not inhibit many microorganisms tested in this study. Films with 1.50% sorbic or benzoic acids had the highest inhibition against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes, however they did not inhibit Staphylococcus aureus. Films with 1.50% sorbic or benzoic acids applied in meat showed the greatest inhibition of Listeria monocytogenes and Escherichia coli O157:H7. These results suggest that the films containing antimicrobials can be used to promote safety and quality of packaged meat, though the physical and mechanical properties of the films could be modified.

ACEITABILIDADE DE PREPARAÇÕES A BASE DE ANCHOITA (Engraulis anchoita)

This study aimed to assess the acceptability of two preparations of Argentine anchovy with 69 untrained panelists of a university in the southern state of Rio Grande do Sul, Brazil, given the importance of fish consumption for health, the need to increase fish consumption by the Brazilian population and the possibility of using a new self-sustaining fishery resource. Acceptability was assessed using a scale of 7 points and purchase intent by a 5-point scale. Chemical composition of preparations was analyzed in the laboratory, following the methodology of Adolfo Lutz Institute. The results showed that the pizza and baked rice with anchovy had excellent acceptability, 92% and 86%, respectively. There was a significant difference between the averages of preparations, in which the pizza achieved better acceptability and better purchase intent than the baked rice with anchovy. In the analysis of the chemical composition of preparations, the pizza had a higher content of protein and fat due to use of other ingredients with high protein content and vegetable oil. It was concluded that both preparations with anchovy could be an excellent vehicle to include fish more often in people’s diet and increase the consumption of fish in Brazil.

Histological and histochemical study of the digestive system of the Argentine anchovy larvae (Engraulis anchoita) at different developmental stages of their ontogenetic development

AbstractIn this work, histological and histochemical features of the larval digestive system of Argentine anchovy Engraulis anchoita were described. Structural changes during ontogenetic development were also characterized, and comparisons between the beginning and the end of larval development were made. Histological sections of larvae were subjected to histochemical and routine histological techniques to localize and differentiate glycoproteins (GPs). Both at an early and a late larval stage, the oesophageal goblet cells reacted more intensely than those of the rest of the digestive tract, and only the oesophagus exhibited metachromasia with toluidine blue techniques at different pHs, thus revealing diverse GPs at different concentrations. The GPs histochemical composition in the intestine varied with the developmental stage and the intestinal zone. The absence of goblet cells characterized the foregut; however, they started differentiation at an advanced stage in the midgut. These cells could be detected in the hindgut both at the beginning and at the end of development. The attached glands showed a varied glycoprotein composition. The digestive tract of E. anchoita presented a high level of complexity, related to the multiple functions of mucus in the digestive tract, such as lubrication, protection, antimicrobial function and ionic and osmotic regulation.

Fine scale distribution constrains cadmium accumulation rates in two geographical groups of Franciscana dolphin from Argentina

Franciscana dolphin is an endemic cetacean in the southwestern Atlantic Ocean and is classified as Vulnerable A3d by the International Union for Conservation of Nature. Cadmium accumulation was assessed in two geographic groups from Argentina; one inhabits the La Plata River estuary, a high anthropogenic impacted environment, and the other is distributed in marine coastal, with negligible pollution. Despite the environment, marine dolphins showed an increase of renal Cd concentrations since trophic independence; while in estuarine dolphins was from 6years. This is associated with dietary Argentine anchovy which was absent in the diet of estuarine dolphins, being a trophic vector of cadmium in shelf waters of Argentina. Cluster analysis also showed high levels of cd in association with the presence of anchovy in the stomach. The difference in the fine scale distribution of species influences dietary exposure to Cd and, along with other data, indicates two stocks in Argentina.

Reproductive success of the Argentine anchovy, Engraulis anchoita, in relation to environmental variability at a mid‐shelf front (Southwestern Atlantic Ocean)

AbstractThe mid‐shelf front (MSF) of the Buenos Aires province continental shelf in the Southwestern Atlantic Ocean plays a central role in the pelagic ecosystem of the region acting as the main spring reproductive area for the northern population of the Argentine anchovy Engraulis anchoita and supporting high concentrations of chlorophyll as well as zooplankton, the main food of anchovy. To investigate the influence of environmental variability on the reproductive success of E. anchoita, we analyzed a 13‐yr time series (1997–2009) of environmental data at MSF including chlorophyll dynamics, as well as zooplankton composition and abundance, ichthyoplankton distributions, and recruitment of E. anchoita. Spring chlorophyll concentrations showed high interannual variability and were mainly influenced by changes in water temperature and vertical stratification, which in turn control nutrient supply to the surface. Chlorophyll dynamics (magnitude, timing, and duration of the spring bloom) explained most of the variability observed in E. anchoita recruitment, most likely via fluctuations in the availability of adequate food for the larvae. Our results suggest that satellite ocean color products can be valuable tools for understanding variability in ecosystem dynamics and its effects on the recruitment of fish.

Influence of heating, protein and glycerol concentrations of film-forming solution on the film properties of Argentine anchovy (Engraulis anchoita) protein isolate

This study was conducted to evaluate the influence of thermal treatment (74, 82, and 90°C), glycerol (30%, 35%, and 40%, w/w) and protein concentrations (3.0%, 3.5%, and 4.0% w/w) of film-forming solution on the properties of Argentine anchovy (Engraulis anchoita) protein isolate (API) films produced by casting. The API presented 88.8% of proteins, 5.5% moisture, 1.3% lipids, 1.0% ash and 53.3% of polar amino acids. The DSC of protein isolate was observed at maximum temperature of 62.2°C and ΔH 6.4J/g. The thickness, water vapor permeability, color difference and opacity of the films were not affected by the experimental variables studied (p>0.05). The lowest solubility, elongation, and highest tensile strength of the films occurred at low temperature, low protein and glycerol concentrations (p<0.05). Micrographs obtained by scanning electron microscopy of the films showed homogeneous surfaces at low temperature.

Long-term changes in the spiny dogfish (Squalus acanthias) trophic role in the southwestern Atlantic

We used a comprehensive dataset on the diet of Squalus acanthias in the southwestern Atlantic Ocean (35–55°S) to test the hypothesis that fishery has caused a decrease in the trophic level of this species (fishing down process). Of 3,644 stomachs examined between the years 1985 and 2010, 2,214 (60.77%) contained prey items. Generalized linear models were used to evaluate the support in our data for five explanatory variables (sex, predator’s total length, season, region and decade) that may explain the consumption of the given prey. The frequency of fish, mainly Merluccius hubbsi, and benthos in the stomachs decreased through time, whereas the squid Illex argentinus and jellyfishes exhibited positive trends. The trophic level of S. acanthias declined from the 1980s to the 1990s due to the high consumption of prey items at lower trophic levels. On the other hand, the consumption of argentine anchovy, Engraulis anchoita, an underexploited species, did not reveal changes through time.

The diet of the South American Tern: the Argentine Anchovy as key prey in the non-breeding season

The Argentine Anchovy (Engraulis anchoita) is one of the most important pelagic fishery resources of the Patagonian Shelf and is known to be an important prey item for several seabirds of the northern Argentine coast. The South American Tern (Sterna hirundinacea) is endemic to the Atlantic and Pacific coasts of South America and, on the Atlantic coast, breeds from central Brazil to southern Argentina. Large non-breeding flocks form during the austral winter and spring from southern Brazil to northern Patagonia. The diet of the South American Tern was studied over three consecutive non-breeding seasons through the analysis of regurgitated pellets. The Argentine Anchovy comprised >80% (index of relative importance) of fish prey in the diet, and remained important throughout the study period. Other important fish prey were Cornalito Silverside (Odonthestes incisa), Pejerrey Silverside (O. argentinensis) and Stripped Weakfish (Cynoscion guatucupa). The growing interest in commercially fishing Argentine Anchovies makes it important that studies are conducted to determine the potential effect of the harvest of Anchovies on South American Terns and other top predators.

Nutritional condition of Argentine anchovy Engraulis anchoita larvae in connection with nursery ground properties

Nutritional condition of anchovy Engraulis anchoita larvae from Northern Argentinean sea was assessed and compared in three areas characterized by dissimilar oceanographic features (estuarine, mixed and shelf waters). Morphometrical, histological and biochemical (RNA/DNA) indexes were used and larvae were compared through different developmental stages. Multivariate analyses performed on normalized morphometric variables showed that larvae from mixed waters where characterized by higher body depths; variables that indicate a better nutritional condition. Mean histological condition index obtained for larvae at intermediate developmental stages was significantly lower in estuarine waters than those estimated with samples from mixed or shelf waters. Anchovy larvae from the mixed water area showed a higher slope in the log RNA versus log DNA relationship than larvae from the other areas, which indicates that the former were in better condition. Also, standardized RNA/DNA index (RNA/DNA s) resulted slightly better in mixed waters than in shelf area, for larvae at intermediate developmental stages, but due to the high variability of RNA/DNA ratio, no significant differences were found between areas. Finally, using literature equations relating RNA/DNA s, temperature and growth, growth rate and growth performance were estimated. Mean growth performance did not differ between areas and was temperature independent. In conclusion, larval condition was relatively high at all stations, but our results suggested that it was slightly better in frontal areas characterized by water masses with intermediate salinities. We also provide evidence that anchovy larvae might not be food limited in any of the studied areas.

Provisioning of mates and chicks by Cayenne and Royal Terns: resource partitioning in northern Patagonia, Argentina

Cayenne (Thalasseus sandvicensis eurygnathus) and Royal Terns (Thalasseus maximus) breed in mixed colonies in Argentina. This paper presents the first detailed information on their breeding diet and assesses differences and overlap between species in the type and size of prey. During 2004 and 2005, observations of prey delivered to mates and chicks were carried out at Punta León, Patagonia. The diet of Cayenne and Royal Terns comprised nine and 10 prey species respectively. Fish comprised >99% of the prey of both species of tern in the two study years. Both species had a fairly specialised diet based on pelagic schooling fish, mostly Argentine Anchovy (Engraulis anchoita) and two species of silversides (Odontesthes spp.). Despite observed overlap in trophic resources, our results showed that Argentine Anchovy was the main prey for Royal Terns, whereas the two species of silversides together with Anchovy comprised the bulk of the diet for Cayenne Terns. Fish delivered by Cayenne Terns were significantly smaller than those by Royal Terns. Results suggested that both type and size of prey may be important factors permitting food partitioning between the two species of tern during the breeding season.

Egg cannibalism in the northern population of the Argentine anchovy, Engraulis anchoita (Clupeidae)

Cannibalism by Engraulis anchoita on their eggs was investigated on the spring spawning ground of the northern population of the species during the 1993–1999 period. Egg distribution was patchy and egg cannibalism was only found in a limited number of fish. The maximum number of eggs found in a single stomach analyzed was 433. This value corresponded to 5.1% of the total number of eggs in the stomach of all fish sampled in 1993. Mean number of anchovy eggs per stomach ranged between 3.9 and 10.0 (mean S.E.: 1.5–5.1) for 1993–1996 and 1.3 (mean S.E.: 0.5) for 1999. Consumption of eggs over a 12-h feeding period represented, on average, 15–33% (mean S.E.: 6.2–20.1) of the total egg mortality within the study area in 1993–1996, but only 2% (mean S.E.: 0.8) in 1999. The mean abundance of copepods in the plankton samples (69,000 copepods/m 2), especially calanoids, in 1999 was higher than in previous years (6000–53,000 copepods/m 2). The same pattern was observed with the number of copepods ingested (400 copepods by fish in the 1993–1996 period and 1200 in 1999). Relationship between consumption rate and density of plankton eggs revealed a marked decrease in the egg cannibalism to low egg density values and an increase of that parameter with the increment of the plankton eggs. There was strong evidence of a decrease in egg cannibalism as copepod density increased. Our results indicate that not only intra-specific predation on anchovy eggs was high, but also anchovy egg cannibalism could be an extra source of energy when the principal food (calanoid copepods) is scarce. In areas where cannibalism was intense, that behavior supplied 91% of the daily energy necessary for reproduction.

Composition and seasonal variation in the diet of the South American sea lion (&lt;i&gt;Otaria flavescens&lt;/i&gt;) from Quequén, Argentina

Diet seasonality in South American sea lions, Otaria flavescens , was studied using 252 scats from a male-exclusive haul-out site located in Puerto Quequen (38°37'S, 58°50'W) Argentina during 2001. Prey species were identified from hard remains and their relative importance was assessed considering frequency of occurrence, abundance and biomass. The main prey consumed by sea lions were teleost fish (20 species), followed by cephalopods (four species) and crustaceans. The raneya, Raneya fluminensis , was the most frequent prey year-round, and the most abundant in autumn and winter. The Argentine anchovy, Engraulis anchoita , and the stripped weakfish, Cynoscion guatucupa , were the most abundant prey in spring and summer, respectively. Seasonal differences in the sizes consumed were only found for C. guatucupa . The sea lions from Puerto Quequen showed a diverse diet, mainly feeding on demersal and pelagic prey. Our study fills a geographical gap on the seasonal variation of the diet of South American sea lions. Two main patterns emerged from studies conducted along the geographic range of the species: (1) O. flavescens is a generalist and opportunist feeder, preying on a wide range of species; mainly those of pelagic and demersal habits, (2) South American sea lions change the frequency and/or specific composition of their diet seasonally, possibly as a result of changes in the relative availability of each species in the environment.

Appendicularians: an important food supply for the Argentine anchovy Engraulis anchoita in coastal waters

Summary The stomach contents of 532 adult specimens of the Argentine anchovy, Engraulis anchoita, caught in coastal waters of the Argentine Sea from 1994 to 1996, were analyzed. Larger amounts of food were found in the stomachs of anchovies collected in the northern surveys (35–40°S), with the highest values attained in 1994. Main diet items were copepods, appendicularians, cladocerans, fish eggs, and pteropods. Anchovies caught in the southern surveys (40–45°S) ingested less food, whereby the main items were copepods and appendicularians. Plankton samples collected simultaneously with the fishing trawls were also analyzed. Except for Fritillaria borealis, which occurred only in plankton samples, the same appendicularian species (Oikopleura dioica and O. fusiformis) were found in both stomach contents and in plankton samples. The Ivlev selectivity index calculated for O. dioica and O. fusiformis and for the different maturity stages of both species were in all cases ∼0, supporting the hypothesis of a non-selective feeding.

Feeding habits of the juvenile striped weakfish, Cynoscion guatucupa Cuvier 1830, in Bahía Blanca estuary (Argentina): seasonal and ontogenetic changes

The aim of this study was to analyze the feeding habits of the juvenile striped weakfish, Cynoscion guatucupa Cuvier, from Bahia Blanca estuary, Argentina. C. guatucupa is one of the most important regional fishing resources although in the last 10 years landings have greatly decreased. The year class strength of fish as well as stock size and yield are determined during the early life stages. Knowledge about the diet of young C. guatucupa may therefore contribute to our better understanding of the influence that the changes occurring in the biota of the estuary exert on the abundance fluctuations of this species. To this end, we investigated the ontogenetic and seasonal dietary changes of C. guatucupa between 1.00 and 12.99 cm total length (age 0+), and we related them to changes in habitat use and prey selection. Two dietary shifts were found during ontogeny. The first shift, at approximately 4 cm total length, involved a change from demersal-pelagic prey (mysid shrimps) to demersal-benthic prey (Peisos petrunkevitchi Burkenroad). The second shift, at approximately 8 cm total length, involved a progressive increase in ichthyophagy (mainly an increase consumption of the Argentine anchovy Engraulis anchoita Hubbs & Marini). Seasonal dietary changes were also found. They evidenced the changes in the availability of organisms. In autumn, the chaetognath Sagitta friderici Ritter-Zahoni, P. petrunkevitchi, and E. anchoita were the dominant prey items; in winter, the copepod Labidocera fluviatilis Dahl along with S. friderici, mysids, and P. petrunkevitchi constituted the majority of the diet; and, in summer, mysids were the most important prey item consumed. Selectivity data showed that whereas some prey items, such as the copepods Acartia tonsa Dana and Paracalanus parvus (Claus) and S. friderici, were consistently negatively selected by all size classes throughout the year, other prey items, such as fish larvae, mysids, and P. petrunkevitchi,were selected in one season and avoided in another. Additional dietary seasonal differences observed in our research indicate that the limited food supply and the low water temperatures are limiting factors for winter juveniles in BahOa Blanca estuary. These factors may also directly influence the more-than-10 cm total length seaward migration of large numbers of C. guatucupa that is registered at the end of every autumn.