Sardine Sardina Pilchardus Research Articles

Age and Growth of European Pilchard Sardina pilchardus (Clupeidae) from the Southwestern Mediterranean Sea

Age and Growth of European Pilchard Sardina pilchardus (Clupeidae) from the Southwestern Mediterranean Sea

Detection of different Betanodavirus genotypes in wild fish from Spanish Atlantic coastal waters (Galicia, northwestern Spain).

The nervous necrosis virus (NNV; genus Betanodavirus) is an aquatic pathogen that is responsible for a neurological disease affecting marine fish. Despite its almost worldwide distribution, global warming could favor the spread of NNV to new areas, highlighting the importance of conducting epidemiological surveys on both wild and farmed marine fish species. In this study, we assessed NNV prevalence in wild fish caught along the Galician Atlantic coast. In total, 1277 fish were analyzed by reverse transcription real-time polymerase chain reaction. Twenty two (1.72%) of those fish tested positive for NNV, including two species in which the pathogen had not yet been reported. The reassortant RGNNV/SJNNV (red-spotted grouper NNV/striped jack NNV) was detected in 55% of NNV-positive individuals, while the remaining 45% harbored the SJNNV-type genome. Moreover, from European Pilchard Sardina pilchardus and Atlantic Mackerel Scomber scombrus, we isolated four reassortant strains that carried amino acid mutations at key sites related to NNV-host interaction.

Quantitative Analysis of Ovarian Dynamics of European Sardine Sardina pilchardus (Walbaum, 1792) during Its Spawning Period

Fish with indeterminate fecundity spawn multiple times throughout a protracted reproductive period. During that period several ovulation events succeed one another, and different oocyte developmental stages co-occur in the ovaries with new oocytes consistently recruiting from one growth phase to the next to form the sequential batches. In this study, we examined in detail the oocyte recruitment and development pattern of the sequential batches in a commercially important fish with indeterminate fecundity, the European sardine. The numbers and sizes of oocytes at different developmental stages were estimated for four phases of the ovulatory cycle (ovarian stages) and during the main spawning season (November–March) by applying the oocyte packing density theory in combination with stereological techniques. General linear models (GLMs) were used to test for changes in oocyte sizes as well as relative oocyte numbers per developmental stage within the different ovarian stages in the successive spawning months. A temporal association between several transition events of the oocyte development process was revealed. Specifically, the final maturation of the advanced batch triggered (a) the recruitment of oocytes from primary to secondary growth phase, (b) de novo vitellogenesis and (c) a surge of yolk deposition in primary vitellogenic oocytes. Oocyte recruitment was completed two days after the ovulation of the advanced batch and relative numbers of primary and secondary growth oocytes were thereafter stable until the next final maturation event. This pattern of oocyte recruitment and growth remained unchanged during the course of the spawning season. This study advances our knowledge on oocyte recruitment and development in fish with indeterminate fecundity, which is key to understanding reproduction and its drivers at the individual and population level.

Length Based Assessments for European Pilchard Sardina pilchardus and European Anchovy Engraulis encrasicolus, in the İzmir Bay, Aegean Sea

In the Mediterranean Sea, European pilchard Sardina pilchardus and European anchovy Engraulis encrasicolus are the most important small pelagic fish regarding their ecological role, and revenue. Here, we perform a comprehensive assessment of length-based methods for those small pelagics from İzmir Bay, Aegean Sea. Therefore, the Length-based Bayesian Estimator and Length-based Spawning Potential Ratio were used to evaluate the stock structure and status of two important small pelagic fish. The length range for Sardina pilchardus was from 7.1 cm to 17.3 cm in TL. The ratios Lmean/Lopt and Lc/Lc_opt were over 1, suggesting truncated length structure and fishing of not too small individuals. The proportion of mature individuals in the catch was far less than half (36%) suggesting that in these fisheries catch consists mostly of immature individuals. The length range for Engraulis encrasicolus was from 5 cm to 15 cm in TL. The ratios Lmean/Lopt and Lc/Lc_opt were over 1 (1.2 and 1.3, respectively), suggesting truncated length structure and fishing of large individuals. The proportion of mature individuals in the catch was over half (52%) suggesting that in these fisheries catch consists of adults. The estimated sizes at median 50% selectivity (SL50) for S. pilchardus (11.1 cm) was ∼0.6 cm shorter than its lengths at 50% maturity (L50) of 11.7 cm, which indicates that a large proportion of the catch was immature. The median estimate of the spawning potential ratio was ∼0.19 for S. pilchardus and ∼0.48 for E. encrasicolus.

Effects of short- and long-term treatments of sardine (Sardina pilchardus) protein hydrolysates on blood lipid concentrations and antioxidant status, in rats fed cholesterol-enriched diets

Hypercholesterolemia is a major risk factor of cardiovascular diseases (CVD). A limited number of experimental studies have shown that sardine protein hydrolysates (SPH) could be a very useful natural compound to prevent hy-percholesterolemia by both improving the lipoprotein profile and modula-ting oxidative stress. In the present study, the effect of short and long term treatments with SPH were examined on serum lipid contents, lipid peroxida-tion and antioxidant enzymes activities in rats fed cholesterol-enriched diet. At day 0, rats were divided into five groups. The group of day 0 was the stan-dard group, and the four remaining groups were divided into two parts of two groups each consuming for 14 or 28 days an hypercholesterolemic diet, and treated (HC-SPH) or not (HC) by gavage with SPH. Compared with day 0, serum TC contents were increased at day 14 and remained unchanged at day 28 in HC-SPH group. These values were decreased in HC-SPH versus HC. Liver and heart TBARS concentrations were increased at day 14 then diminished at day 28 in HC-SPH group. Liver and heart SOD and CAT activities were decrea-sed at short term then remained unchanged at long term in HC-SPH group. In addition, these activities were enhanced in HC-SPH versus HC. In conclusion, these results indicate the potential effects of short and long term treatments of SPH to improved cholesterolemia and reduced radical attack in rats fed high-cholesterol diets.

Effect of Temperature on the Daily Increment Deposition in the Otoliths of European Sardine Sardina pilchardus (Walbaum, 1792) Larvae

Otolith microstructure analysis is a valuable tool to evaluate the relationship between larval age and growth and how it relates to environmental variability. Otolith growth and daily increment deposition were analyzed in sardine (Sardina pilchardus) larvae reared in the laboratory under different temperatures (13, 15, and 17 °C), with a diet rich in microalgae, rotifers, and copepods Acartia grani. The number and width of growth increments, first-check and otolith diameter were determined in the otoliths and then related to larval age and total length. At hatching, the sagittal otoliths consisted of a lenticular core with a diameter of 10.56 μm (±1.07 μm SD). Somatic growth increased with the increasing temperature and the growth rate of larvae reared at 13 and 15 °C was significantly lower than for larvae reared at 17 °C. At 17 °C, otoliths exhibited a higher diameter with wider increments than at 13 °C. There was a high variability of increment counts-at-age for larvae reared within the same temperature treatment. The increase of growth increments with larval size was higher for larvae reared at 17 °C until 35 days post-hatching than those growing at 15 °C. Scanning electronic microscopy confirmed that increments are deposited daily, with an average width smaller than 1 µm and as low as 0.33 μm, therefore impossible to distinguish using light microscopy. At colder temperatures, larval otoliths had thinner and less marked increments and lower growth rates, which can lead to incorrect age determinations. The effect of temperature on the otolith microstructure can help in identifying strong temperature gradients experienced by wild sardine larvae.

Effect of food availability on the growth and age determination of European sardine (Sardina pilchardus Walbaum, 1792) larvae

AbstractAccurate assessment of age and growth of fish is essential to understand population dynamics, namely for age-structured stock assessment and for determining vital rates of fish (e.g. age at sexual maturity) and their relationship with environmental variability. To validate the daily deposition in the otoliths of European sardine (Sardina pilchardus) larvae, these were reared with a range of food densities translating into feeding rates extending from less than required for maintenance to saturated feeding levels. When exogenous feeding began, a high variability in the relationship between number of growth increments (GI) and elapsed days after hatching (dph) was observed, irrespective of the feeding treatment. GI counts using a light microscope were less than one per day for larvae <15 dph (ranging from 0.17–0.43 GI day−1) and similar for larvae reared with different food concentrations. The rate of GI count vs age was significantly higher for larvae older than 15 dph. GI count from 3–30 dph was lower than one per day (0.45–0.75 GI day−1 95% CI) for fed larvae 3–30 dph. Scanning electron microscopy confirmed the daily deposition of GI and revealed some increment widths around 0.2 μm, particularly during the first week post-hatch. Otoliths of wild sardine larvae exhibited narrow GI (<0.5 μm) comparable with reared larvae. This study demonstrates that during the first weeks after hatch the daily increment deposition is underestimated using traditional light microscopy, which must be taken into account in future works determining wild sardine larval growth.

Interannual trophic behaviour of a pelagic fish predator in the western Mediterranean Sea

The exploitation of forage fish species can modify the functioning of marine ecosystems potentially impacting the population status of predators. This may be the case for the western Mediterranean Sea, where a reduction in the biomass of two key pelagic forage fish (European anchovy Engraulis encrasicolus and European sardine Sardina pilchardus) could produce a change in the diet composition of their main predators, which would consume alternative preys or change the size of the prey consumed. Here, we aimed to investigate the potential effect of biomass reduction of sardine and anchovy in the western Mediterranean Sea on the trophic preferences of the little tunny (Euthynnus alletteratus), a medium-sized predator that present a high consumption of these forage fish. We compared its interannual trophic ecology by combining the analysis of stomach contents and stable isotopes. Specifically, we examined if the diet of little tunny changed in its main trophic habits (diet composition, prey size, and trophic niche) during a 6-year period. We found that small pelagic fish, especially clupeiformes, were the most important prey group for the little tunny during the study period. However, we found changes in the body size of anchovy and the relative importance of sardine in recent years, probably reflecting the reported reduction in the biomass and body size of these two forage fish in the study area. In addition to these changes, we found an increase in some demersal and benthopelagic species in the diet of little tunny, which could act as an alternative diet resource.

Diet Composition and Isotopic Analysis of Nine Important Fisheries Resources in the Eastern Adriatic Sea (Mediterranean)

We examined how the trophic ecology of nine economically important marine taxa varied across three distinct areas of the Adriatic Sea. These taxa included three species of demersal fishes (European hake Merluccius merluccius, red mullet Mullus barbatus, black-bellied angler Lophius budegassa) and two species of decapod crustaceans (Norway lobster Nephrops norvegicus, deep-water rose shrimp Parapenaeus longirostris) and four species of pelagic fishes (sardine Sardina pilchardus, anchovy Engraulis encrasicolus, Mediterranean horse mackerel Trachurus mediterraneus, Atlantic horse mackerel Trachurus trachurus). We used two complementary methods that differed in their temporal context to examine and compare diet. Stomach contents analysis was used to describe the short term diet while stable isotope analysis was used compare long-term assimilated diet. Results showed that although there were spatial differences in what each species consumed, and in their trophic and isotopic niches, each species fed at similar trophic position across locations, indicating similar ecological function. Comparisons of biomass-weighted trophic position (δ15N) and consumer body size (log2 mass) showed evidence for a common isotopic size spectrum across areas, indicating the existence of a size-structured food web. In turn this allowed us to provide a first estimate of the predator–prey body mass ratio (PPMR) for this area (655:1). Results obtained within this study, in future, could be used for ecological modeling and improved long-term management of the Adriatic Sea’s marine resources.

Effect of Different Salting Methods on Physicochemical Properties, Quality Characteristics and Microbiological Analysis of Sardine (Sardina Pilchardus) during Ripening at Ambient Temperature

Effect of Different Salting Methods on Physicochemical Properties, Quality Characteristics and Microbiological Analysis of Sardine (Sardina Pilchardus) during Ripening at Ambient Temperature

Evaluation of Histamine Contents during the Fish Meal Production Process

Abstract Evaluation of histamine levels at various stages of manufacturing fish meal made from European pilchard Sardina pilchardus by-products was conducted on two batches which are distinguished by the quality of raw materials expressed through total volatile basic nitrogen (TVBN) content. The goal was also to assess the impact of the reuse of the concentrated stickwater, the liquid from the pressing process of fish meal. The results revealed that the level of raw material deterioration influenced the level of histamine in the finished product. When the freshness of the raw material is acceptable (TVBN content: 30 mg/100 g), histamine contents recorded in the finished product remain clearly below the limit value of 500 ppm. In this case, incorporation of concentrated stickwater into press cake before drying did not affect the concentration of histamine accumulated in the finished product. When the raw material was spoiled (TVBN content: 120 mg/100 g), the recorded histamine content was twice the limit value (975.1 ± 33.9 ppm).

Determinism of Temporal Variability in Size at Maturation of Sardine Sardina pilchardus in the Bay of Biscay

Age and size at maturation appear as key parameters governing the dynamics of a population as they affect growth rate, fecundity, and survival. The expression of such life history traits is determined by genetic make-up and modulated by environmental factors mainly through phenotypic plasticity. Moreover, fishing, besides decreasing population size and changing demographic composition can alter allelic frequencies through fisheries-induced evolution by selecting for some particular traits. In the Bay of Biscay, a decreasing trend in both sardine body condition and size-at-age has recently been pointed out at the population level. The Probabilistic Maturation Reaction Norm (PMRN) approach was applied to help disentangle phenotypic plasticity and genetic changes. Based on the analysis of sardine spawning seasonality, PMRN was estimated by considering body condition as additional life-history state variable to predict the onset of maturation. The resulting PMRN was then used to investigate temporal trends in reaction norm midpoints to test whether changes in length at maturation can be explained by plastic and/or evolutionary adaptive change. Overall, our results emphasize for the first time that including sardine body condition as explanatory variable improves predictions of maturation probability. We found that better individual condition increases maturation probability. The assessment of temporal changes in length at maturation confirms the low plasticity in this trait for a species maturing mostly at age-1 and advocates for the use of a monthly time scale when investigating PMRNs for this species. Beside environmental variables included in this analysis (water temperature, chlorophyll-a, and population biomass) that only show a weak correlation with PMRN midpoints, our results reveal no evidence for recent fisheries-induced evolution in the sardine stock of the Bay of Biscay. They suggest that the short-term variability in length at maturation is strongly dependent upon individual growth which is likely driven by environmental factors. For sardine fisheries management, our study highlights the need to consider both the length-composition data and the seasonality within a stock assessment model. Finally, we discuss the fact that considering individual growth trajectories should improve our understanding of the relationship between environmental variability and changes in maturation for sardine.

SOS small pelagics: A safe operating space for small pelagic fish in the western Mediterranean Sea

Sustainable fishing practices must ensure human wellbeing by safeguarding the integrity of marine life-supporting systems. Unfortunately, a significant challenge to fisheries management is that sustainable fishing levels can decline, often synergistically, by co-occurring with climate-driven environmental stressors. Within one of the most impacted marine areas in the world, and encompassing a number of highly targeted commercial species, the small pelagic fish community of the western Mediterranean Sea has recently shown signs of collapse. In this study, we identify a worrying coincidence where fishing hotspots for the commercially valuable European sardine Sardina pilchardus and anchovy Engraulis encrasicolus occur in marine areas mostly affected by climate change. To identify these areas, we overlayed detailed, spatially explicit measurements of fishing pressure with the finest-scale maps of cumulative climate change impacts onto these species. According to our results, doubly impacted marine areas largely occur in the north-western Mediterranean Sea, with climate and fisheries mostly affecting European sardine. Reducing local stressors (i.e., fishing pressure) in highly impacted areas may contribute to maintain these communities within a “safe operating space” (SOS), where they remain resilient to climate change. Accordingly, the redistribution and/or reduction of fishing intensity may alleviate pressure in those areas already affected by climate change. Sustainable fishing strategies may benefit, therefore, from the SOS concept and the spatial assessments provided in this study.

Growth and Status Stock, of The Sardine Sardina Pilchardus (Walbaum, 1792) Among the Moroccan Atlantic Center-Case of Agadir Bay

Growth and Status Stock, of The Sardine Sardina Pilchardus (Walbaum, 1792) Among the Moroccan Atlantic Center-Case of Agadir Bay

A review of reproduction biology and spawning/ nursery grounds of the most important Adriatic commercial fish species in the last two decades

Recently, despite long-term systematic research of the Adriatic Sea ecosystem, the necessity to improve the existing protection of commercially exploited species occurred since the status of many renewable marine stocks were not in good state. In order to realize that review of scientific knowledge gather within the last two decades was required. In this paper emphasis has been placed on all the scientific knowledge concerning the reproductive biology, spawning and nursery grounds of four ecologically and economically important Adriatic fish species – sardine Sardina pilchardus, anchovy Engraulis encrasicolus, European hake Merluccius merluccius, Common pandora, Pagellus erythrinus. Main aim of this review was to establish new scientific platform that in near future should result with better conservation measures that will insure long-term sustainability of exploited marine living resources.

The reproduction and growth of the sardine Sardina pilchardus in West Mediterranean, Morocco

The reproduction and growth of the sardine Sardina pilchardus in West Mediterranean, Morocco

Comparison of Growth Parametres Between Sardine Sardina Pilchardus (Walbaum, 1792) and Anchovy Engraulis Encrasicolus (Linnaeus, 1758) from the Eastern Adriatic Sea

Sardine Sardina pilchardus (Walbaum, 1792) and anchovy Engraulis encrasicolus (Linnaeus, 1758), besides being ecologically very important pelagic resources, are also the most numerous fish species in Croatian fisheries landings. Hence, the aim of this study was to compare sardine and anchovy growth parameters: length, length-weight relationship, condition and age population structure. All samples (N=3313) were collected from purse seine catches of eastern Adriatic Sea, during period June 2015 – August 2016. Total lengths of sardine and anchovy ranged from 10.5 to 17.5 cm (average ± SD: 13.94 cm ± 1.07) and from 10.0 to 17.5 cm (average ± SD: 14.09 cm ± 0.88), respectively. Both sardine and anchovy length-weight relationship indicated positive allometry, although allometric coefficient was higher in anchovy (b=3.201) than in sardine (b=3.069). In general, condition of both species grew with fish length. Sardine and anchovy age composition varied from one to five years, while most of the analysed samples belonged to the 3 year class. Growth parameters were for anchovy: L∞=18.36cm; K=0.317; t0= -1.89 and for sardine L∞=19.71 cm; K=0.286; t0= -1.82.

Leucism in the European sardine Sardina pilchardus (Clupeidae)

• First record of leucism in the European sardine. • Leucism in fish as an ecological indicator. • Color abnormality as an indicator of the recent historic decline of sardine. The first case of abnormal leucism in the European Sardine or Pilchard Sardina pilchardus (Walbaum, 1792) is reported. A few sardines with abnormal pigmentation were captured by fishermen in the northern part of the Gulf of Cadiz (SW Atlantic coast), between Portugal and Spain, and one specimen was presented to the authors for examination. Species identification was verified using both morphological and genetic criteria. Despite the relative abundance of sardines along the Atlantic coast of the Iberian Peninsula, the current specimen represents the first known case of leucism in S. pilchardus . The observed colour aberration may have been caused by either heavy metal pollutants and/or a high level of endogamy in this heavily exploited local sardine stock.

Study of the Toxic Contaminants Cadmium and Lead in Sardines (Sardina pilchardus) in the Bay of Algiers (Algeria)

ABSTRACTThe study of the discharge of metallic pollutants into the marine environment through biological material such as sardines makes it possible to evaluate the quality of the biological resources and of the marine environment. The sardine (Sardina pilchardus) is the most popular species for fishing and the most consumed species by the Algiers population. Two toxic metals that can affect human health are studied in this fish. A year of sampling with fishermen was conducted. Sampling was done in the spring, in the autumn, and in April between April 2014 and April 2015. Sampled sardines were grouped by size classes. The gills and muscle were recovered by size classes. The results were explored using a principal components analysis and compared by a Mann-Whitney distribution test. An atomic absorption spectrophotometer was used in the laboratory for analysis. The most important results show that lead levels were higher than those of cadmium in the gills and muscle. For sardines, lead contamination appears to have both gill and food origins. Mann-Whitney comparison tests confirmed this homogeneous distribution of lead between the gills and muscle. The correlation between cadmium in the gills and height or weight is more substantial than that with muscle. The origin of cadmium in sardines is branchial. The food origin appears secondary. From our point of view, the effect of season, i.e., winter (December) and spring (April), favors an increase in metal levels in parallel to the production reserves planned for spawning. The effect of season was observed by use of a biplot. A significant reduction in cadmium and lead content was observed in September. The high temperature, an environmental factor, induced stress that reduced the metal concentrations and the decontamination induced by the issuance of genital products in early summer.

Number Dynamics of Mass Ichthyoplankton Species in the Waters of Morocco

Data on the number dynamics of the mass fish species at early developmental stages in the northern and southern regions of Morocco during 2003–2016 have been analyzed. The values of number index and absolute number of eggs and larvae of the mass fish species have been calculated. As a rule, the values of absolute number of ichthyoplankton are 1.3–2.9 times higher than of the number index values. In general, the trends of interannual fluctuations of these values are similar. The study revealed that the patterns of fluctuations of the subtropical fish species at early developmental stages (European pilchard Sardina pilchardus, Atlantic horse mackerel Trachurus trachurus, and mackerel Scomber japonicus colias) are similar over the whole study area within the Morocco economic zone (32°–21° N). The fluctuations in the number of the tropical fish eggs and larvae (round sardinella Sardinella aurita and Cunene horse mackerel T. trecae) are not identical in the northern and southern parts of Morocco. No clear correlation between these fluctuations in the bordering regions is revealed.