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Axel Temming - One of the best experts on this subject based on the ideXlab platform.
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metabolic costs of spontaneous swimming in Sprattus Sprattus l at different water temperatures
PLOS ONE, 2019Co-Authors: Laura Meskendahl, Jens-peter Herrmann, Rene Pascal Fontes, Axel TemmingAbstract:Oxygen uptake (MO2; mgO2 fish-1h-1) of fish groups was measured at temperatures between 10–19°C in an intermittent-flow respirometer to quantify the metabolic costs of spontaneous swimming patterns in the small clupeid Sprattus Sprattus. Movements of individual fish within the school were tracked automatically during respirometry. Oxygen uptake was then related to mean swimming speeds and the number of sharp turns (>90°), which are common behavioural elements of spontaneous swimming in clupeid fish. Different possible model formulations for describing the relationship between respiration and swimming patterns were compared via the AIC. The final model revealed that costs for sharp turns at a frequency of 1 s-1 doubled the metabolic costs compared to those with zero turns but with likewise a moderate swimming speed of 0.28 body length -1. The cost for swimming doubled if the swimming speed was doubled from 0.28 to 0.56 BLs-1 but increased by a factor of 4.5 if tripled to 0.84 BLs-1. Costs for transport were minimal at a speed of 0.4 body lengths s-1 at all temperatures. New basic input parameters to estimate energy losses during spontaneous movements, which occur typically during foraging in this small pelagic fish, are provided.
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vertically resolved prey selectivity and competition of baltic herring clupea harengus and sprat Sprattus Sprattus
Marine Ecology Progress Series, 2013Co-Authors: Matthias Bernreuther, Daniel Stepputtis, Jorn Schmidt, Axel TemmingAbstract:Prey selectivity of Baltic herring Clupea harengus and sprat Sprattus Sprattus was studied in the Bornholm Basin, Baltic Sea, in June 2001. A total of 165 sprat stomachs (10 to 15 cm total length, TL) and 214 herring stomachs (12 to 30 cm TL) were analysed. The diel vertical distribution of zooplankton prey was analysed by multi-net samples; clupeid distributions were estimated by hydroacoustic measurements. These measurements enabled us to describe the diel feeding rhythm and to estimate vertically resolved selectivity indices for the 2 most important zoo-planktivores in the Baltic Sea. Diet composition of herring and sprat were similar (mainly copepods and cladocerans), resulting in strong competition. Possibly to reduce this competition, both species were partly specializing on certain prey species (sprat: Podon spp.; herring: Evadne nordmanni and Temora longicornis) and copepodite stages (sprat: adult [C6] males of Pseudocalanus acuspes; herring: C6 females of P. acuspes). Sprat and, to some extent, herring exhibited a marked shift in prey preference between day and night. Sprat mainly selected T. longicornis during the day and Podon spp. during the night, while herring mainly selected T. longicornis during the day and E. nordmanni during parts of the night. A comparison of the field stomach contents with the estimated gastric evacuation predicted by parameters based on laboratory experiments indicated that sprat fed during the night, while herring did not or only to a minor extent. Comparison of our zooplankton sampling scheme with commonly used sampling designs revealed that investigations which consider both time and stage are needed to fully understand the feeding selectivity dynamics of herring and sprat in the Baltic Sea. However, the objective of a selectivity study should determine the most appropriate zooplankton sampling scheme.
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effect of temperature on the gastric evacuation in sprat Sprattus Sprattus
Journal of Fish Biology, 2009Co-Authors: Matthias Bernreuther, Axel Temming, Jens-peter HerrmannAbstract:Gastric evacuation of groups of juvenile (mean 63 mm total length, LT, 0.283 g dry mass, MD) sprat Sprattus Sprattus feeding on brine shrimp Artemia sp. nauplii was studied at six temperatures (7.5, 10, 13, 16, 19.5 and 21.5 degrees C) in the laboratory. Gastric evacuation was best described with a general model: St=S0(1-B)-R(1-B)t)1-B(-1), with St=stomach content at time t, S0=stomach content at time 0, t=time , R, B=constants. The shape parameter was estimated as B=0.668. For comparison with other studies, an exponential model was fitted also to the data. The evacuation constant (R) of the general gastric evacuation model increased exponentially with temperature between 7.5 and 16 degrees C. The slope of the increase was reduced between 16 and 19.5 degrees C and a slight decrease was observed between 19 and 21.5 degrees C. Additionally, the effect of mean MD (range 0.286-1.025 g) was examined. A simple power function (R=R'MDC) described the influence of predator mass on exponential evacuation constant with C=0.503. The results of this investigation were integrated into a consumption model for the calculation of daily rations of S. Sprattus: C24=0.0177e0.0775T/S0.668 MD0.503 (1-{1[1+e(-0.659)(T-23.989)](-1)})24/S0.668, with T=ambient temperature (degrees C) and /S0.668= mean of field stomach contents (g dry) individually raised to the power of 0.668.
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Investigating the selective survival of summer-over spring-born sprat, Sprattus Sprattus, in the Baltic Sea
Fisheries Research, 2008Co-Authors: Hannes Baumann, Rudi Voss, Hans-harald Hinrichsen, Volker Mohrholz, Joern O. Schmidt, Axel TemmingAbstract:To better understand recruitment variability in small pelagic fish like sprat, it is important to know when during the extended spawning season the successful recruits are predominantly produced and which environmental factors determine potential survival windows. Here, we inferred the temporal origin of 2-year classes (2002–2003) of western and central Baltic sprat by means of otolith microstructure analysis, and found that in both years recruits mainly originated from the summer months June and July. In both years, this period coincided with temperature conditions in the surface layer of >12 °C and peak seasonal abundance of the largest copepod stages of Acartia spp., the major prey item of sprat larvae. The peaks in seasonal sprat egg abundance, however, occurred in April 2002 and March 2003 and therefore about 1–2 months earlier than the long-term mean spawning peak of sprat in this area (end of May/beginning of June). We hypothesize that increased temperatures in the bottom layer of the Baltic, where the pre-spawning sprat stock concentrates during winter months, potentially caused this shift in sprat spawning patterns, although early spring temperatures and feeding conditions in upper water layers were still unfavourable for larval survival. Sprat recruitment, however, was comparatively strong in both 2002 and 2003, suggesting that summer born individuals had high enough survival rates to compensate for the spawning shift, possibly due to high summer temperatures, limited dispersion, and low predation mortalities by Baltic cod as the major predator of sprat. Recruits were on average younger in 2003 than 2002, yet length distributions in October were almost identical, likely because a period of substantially higher temperatures in July/August 2003 promoted faster initial (larval) growth of survivors. Given the strength of the 2003 year class, in spite of lower overall prey concentrations in 2003 than 2002 in the study area, our findings appear to emphasise the paramount importance of summer temperatures as the recruitment determinant in Baltic sprat
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Depth-dependent nutritional condition of sprat Sprattus Sprattus larvae in the central Bornholm Basin, Baltic Sea
Marine Ecology Progress Series, 2007Co-Authors: Andreas Dänhardt, Catriona Clemmesen, Myron A. Peck, Axel TemmingAbstract:Bimodal depth distribution patterns observed for sprat Sprattus Sprattus larvae in previous field studies conducted in the deep basins of the Baltic Sea have led researchers to hypothesise that larval sprat condition was depth-dependent. We examined this hypothesis by measuring morphological, biochemical and otolith-based proxies for nutritional condition in sprat larvae collected in discrete 5 m depth intervals from the surface to the bottom in the central Bornholm Basin. Similar to earlier studies, larval sprat were most abundant in 2 depth strata (0 to 10 and 65 to 75 m). Their nutritional condition in surface and deep waters was not uniformly expressed by the different indices. For example, sprat larvae from 0 to 10 m could not be distinguished from conspecifics caught at 65 to 75 m by a long-latency condition proxy (otolith-based growth rates). Similarly, a medium-latency proxy (RNA:DNA) did not suggest differences in condition between the depths. However, short-latency proxies (protein:standard length and DNA:dry weight) supported the depth-dependent condition hypothesis. The lack of correspondence and pitfalls associated with the use and interpretation of multiple condition indices (e.g. the influences of temperature and body size) are discussed and recommendations to strengthen these various metrics are provided.
Dursun Avsar - One of the best experts on this subject based on the ideXlab platform.
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population parameters of sprat Sprattus Sprattus phalericus risso from the turkish black sea coast
Fisheries Research, 1995Co-Authors: Dursun AvsarAbstract:Abstract Population parameters of the sprat ( Sprattus Sprattus phalericus RISSO), collected from the Turkish Black Sea cost between 1990 and 1992 were investigated. The mean annual growth rates in length and weight were 25.1 mm and 2.3 g, respectively. Von Bertalanffy growth constants were calculated as W ∞ = 15.78 ( g ), L ∞ = 137.59 ( mm ), K = 0.42 (year −1 ) and t 0 = −1.09 (year). The growth parameters found in this study were compared with those from previous studies in the Black Sea and other areas. Total mortality rate and its components were Z = 1.64, M = 0.73 and F = 0.91. All mortality rates increased during winter-spring and decreased in autumn. A slight over-exploitation was found on the stock of the Turkish Black Sea sprat.
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a stock differentiation study of the sprat Sprattus Sprattus phalericus risso off the southern coast of the black sea
Fisheries Research, 1994Co-Authors: Dursun AvsarAbstract:Abstract Stock differentiation studies of sprat ( Sprattus Sprattus phalericus Risso) from the Black Sea coast of Turkey have been carried out morphometrically and meristically applying the generalised distance of Mahalanobis (GDM) and also physiologically using three-level nested ANOVA (TLNA). Fifteen morphometric measurements, together with nine meristic counts and fat concentration of wet tissues of sprat have been used in the analyses of GDM and TLNA, respectively. Insufficient differences in general phenotypic, genotypic ( P > 0.01) and physiological ( P > 0.05) characteristics implied the existence of a single unit stock. Samples collected in the same period showed greater similarity than those taken from the same areas in different periods.
Friedrich W Koster - One of the best experts on this subject based on the ideXlab platform.
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climate zooplankton and pelagic fish growth in the central baltic sea
Ices Journal of Marine Science, 2005Co-Authors: Christian Mollmann, Marina Fetter, Georgs Kornilovs, Friedrich W KosterAbstract:Oceanographic conditions in the brackish central Baltic Sea are strongly linked to atmospheric forcing and the unusual period of persistently strong westerlies that, since the late 1980s, have resulted in an increase in average water temperatures and decreasing salinity. These changes in temperature and salinity resulted in a change in the dominance of the mesozooplankton community from Pseudocalanus sp. to Temora longicornis and Acartia spp. Similar to the copepod community, the central Baltic fish community shifted from cod (Gadus morhua), dominant during the 1980s, to sprat (Sprattus Sprattus), dominant during the 1990s. Further, the commercially important pelagic fish species herring (Clupea harengus) and sprat exhibited reductions in growth. Using Principal Component and Correlation Analyses we investigated the temporal variability in the importance of the food supply as well as competition on condition of central Baltic pelagic fish species. Our results indicate that herring condition results from a combined effect of changes in the food environment and increased competition with sprat, while sprat condition appeared to be primarily determined by intra-specific competition.
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estimating baltic sprat Sprattus Sprattus balticus s population sizes from egg production
Fisheries Research, 2004Co-Authors: Gerd Kraus, Friedrich W KosterAbstract:The sprat (Sprattus Sprattus balticus S.) population size in the Bornholm Basin, one of the major spawning areas of the species in the Baltic Sea, was estimated with the daily egg production method. Egg abundance, stock structure, sexual and gonadal maturation, spawning frequency and the batch fecundity of sprat throughout the sprat spawning season were simultaneously investigated to obtain an estimate of the population size at spawning time. The results confirmed the population estimate from a hydroacoustic survey, but contrasted spatially down-scaled results from an area dis-aggregated stock assessment model applying fisheries statistics. Conflicting results from both latter methods have previously hampered quantitative studies on recruitment processes of sprat and cod, for example the estimation of predation pressure on cod eggs by sprat. The egg production method did not allow an estimation of the population size of sprat in the entire assessment area larger than the Bornholm Basin, i.e. ICES sub-division 25. This failure is caused by sprat spawning activity outside the Bornholm Basin, not covered by the standard egg surveys and has consequences for the general applicability of available egg abundance time series to retrospectively estimate sprat stock development.
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egg cannibalism in baltic sprat Sprattus Sprattus
Marine Ecology Progress Series, 2000Co-Authors: Friedrich W Koster, Christian MollmannAbstract:Throughout the last 2 decades a shift from a cod- to a sprat-dominated system occurred in the upper trophic levels of the Central Baltic Sea. This was caused by a decline in the cod stock, due to recruitment failure and high fishing intensity, resulting in a decrease in predation pressure on sprat. Concurrently with the lowest cod stock size on record, sprat reached biomass values of above 2 x 10 6 t in 1992, being relatively stable afterwards. Besides predation mortality through cod and in recent years also an increasing fishing pressure, cannibalism on eggs may be a compensatory process limiting the reproductive success of sprat and hence contributing to the population regulation in the Central Baltic. Based on sprat stomach sampling on 21 cruises between March 1988 and July 1996 cannibalism on sprat eggs was investigated in the Bornholm Basin, one of the main spawning areas of Central Baltic sprat. Using a model of gastric evacuation to estimate daily food intake rates and a Virtual Population/Extended Survivor Analysis for computing predator population sizes, egg cannibalism rates were estimated. These were compared to egg abundance data from ichthyoplankton surveys and to preliminary estimates of seasonal egg productions. The study revealed significant interannual differences in the intensity of sprat egg cannibalism with considerable predation in 1990 to 1992 (>15% of the egg abundance during peak spawning and >60% of the seasonal production) and a reduction in most recent years (<16% of the corresponding abundance and production). As a possible reason for these differences a combination of changes in the vertical overlap of predator/prey and variability in the food environment were identified. Shortcomings of the applied methods and the possible impact of cannibalism on the reproductive success and population development of sprat in the Central Baltic Sea are discussed.
Christian Mollmann - One of the best experts on this subject based on the ideXlab platform.
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feeding ecology of pelagic fish species in the gulf of riga baltic sea the importance of changes in the zooplankton community
Journal of Fish Biology, 2010Co-Authors: Ain Lankov, Mart Simm, Maria Pollupuu, Henn Ojaveer, Christian MollmannAbstract:: The feeding ecology of four pelagic fish species was studied in relation to their prey availability in the Gulf of Riga (Baltic Sea) during the summer 1999-2006. The zooplankton community was dominated by the cladoceran Bosmina longispina, rotifers Keratella cochlearis and K. quadrata and the copepod Eurytemora affinis, with the highest interannual variability in abundance recorded for B. longispina. The last influenced the diet of adult sprat Sprattus Sprattus, juvenile smelt Osmerus eperlanus and three-spined stickleback Gasterosteus aculeatus as these were strongly selecting for B. longispina. The fish feeding activity did not match the abundance dynamics of their preferred prey, suggesting that fishes may switch to consume other prey in case the preferred diet was limited. A considerable dietary overlap indicated high potential competition between pelagic fish species. While herring Clupea harengus membras and G. aculeatus were relying on very different food, the diets of young O. eperlanus and G. aculeatus were very similar. Interannual variability in zooplankton composition and abundance significantly affected the diet composition of fishes, but those changes were insufficient to exert a consistent influence upon fish feeding activity and total amounts of zooplankton consumed.
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the influence of hydrography and predation by herring clupea harengus and sprat Sprattus Sprattus on mesozooplankton long term dynamics in the central baltic sea
(Doctoral thesis PhD) Christian-Albrechts-Universität Institut für Meereskunde Kiel 139 pp, 2006Co-Authors: Christian MollmannAbstract:The present study investigated the long-term dynamics of the copepod species Pseudocalanus elongatus, Temora longicornis and Acartia spp. as well as cladoceran species Bosmina coregoni maritima, Evadne nordmanni and Podon spp. in an environment, i.e. the Central Baltic Sea, characterized by changes in the hydrographic regime and in predation pressure through pelagic clupeids herring (Clupea harengus) and sprat (Sprattus Sprattus). A clear association between the biomass of P. elongatus and higher salinities, as well as lower temperatures in spring was found, whereas the biomass of T. longicornis and Acartia spp. was positively correlated to water temperature. All cladoceran species also took advantage of higher water temperatures, while decreasing salinity only affected E. nordmanni and Podon spp. The analyses of a predation effect revealed no substantial impact of herring on the mesozooplankton dynamics, whereas a significant predation pressure of sprat in spring on copepodite stages CV/VI of P. elongatus and T. longicornis was identified. In parallel mortality rates of these copepods increased, which indicates a contribution of the sprat population to the decline of the P. elongatus and T. longicornis abundance. A limited influence of sprat predation on the dynamics of cladocerans was detected.
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climate zooplankton and pelagic fish growth in the central baltic sea
Ices Journal of Marine Science, 2005Co-Authors: Christian Mollmann, Marina Fetter, Georgs Kornilovs, Friedrich W KosterAbstract:Oceanographic conditions in the brackish central Baltic Sea are strongly linked to atmospheric forcing and the unusual period of persistently strong westerlies that, since the late 1980s, have resulted in an increase in average water temperatures and decreasing salinity. These changes in temperature and salinity resulted in a change in the dominance of the mesozooplankton community from Pseudocalanus sp. to Temora longicornis and Acartia spp. Similar to the copepod community, the central Baltic fish community shifted from cod (Gadus morhua), dominant during the 1980s, to sprat (Sprattus Sprattus), dominant during the 1990s. Further, the commercially important pelagic fish species herring (Clupea harengus) and sprat exhibited reductions in growth. Using Principal Component and Correlation Analyses we investigated the temporal variability in the importance of the food supply as well as competition on condition of central Baltic pelagic fish species. Our results indicate that herring condition results from a combined effect of changes in the food environment and increased competition with sprat, while sprat condition appeared to be primarily determined by intra-specific competition.
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egg cannibalism in baltic sprat Sprattus Sprattus
Marine Ecology Progress Series, 2000Co-Authors: Friedrich W Koster, Christian MollmannAbstract:Throughout the last 2 decades a shift from a cod- to a sprat-dominated system occurred in the upper trophic levels of the Central Baltic Sea. This was caused by a decline in the cod stock, due to recruitment failure and high fishing intensity, resulting in a decrease in predation pressure on sprat. Concurrently with the lowest cod stock size on record, sprat reached biomass values of above 2 x 10 6 t in 1992, being relatively stable afterwards. Besides predation mortality through cod and in recent years also an increasing fishing pressure, cannibalism on eggs may be a compensatory process limiting the reproductive success of sprat and hence contributing to the population regulation in the Central Baltic. Based on sprat stomach sampling on 21 cruises between March 1988 and July 1996 cannibalism on sprat eggs was investigated in the Bornholm Basin, one of the main spawning areas of Central Baltic sprat. Using a model of gastric evacuation to estimate daily food intake rates and a Virtual Population/Extended Survivor Analysis for computing predator population sizes, egg cannibalism rates were estimated. These were compared to egg abundance data from ichthyoplankton surveys and to preliminary estimates of seasonal egg productions. The study revealed significant interannual differences in the intensity of sprat egg cannibalism with considerable predation in 1990 to 1992 (>15% of the egg abundance during peak spawning and >60% of the seasonal production) and a reduction in most recent years (<16% of the corresponding abundance and production). As a possible reason for these differences a combination of changes in the vertical overlap of predator/prey and variability in the food environment were identified. Shortcomings of the applied methods and the possible impact of cannibalism on the reproductive success and population development of sprat in the Central Baltic Sea are discussed.
Fredrik Arrhenius - One of the best experts on this subject based on the ideXlab platform.
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feeding preferences of herring clupea harengus and sprat Sprattus Sprattus in the southern baltic sea
Ices Journal of Marine Science, 2004Co-Authors: Michele Casini, Massimiliano Cardinale, Fredrik ArrheniusAbstract:No field studies have been performed on the selectivity of herring and sprat in the southern Baltic Sea in relation to their entire range of prey. Accordingly, we tested in the field the following hypotheses: (i) sprat and herring are selective feeders and (ii) sprat and herring selectivity is size- and season- dependent. The results show that (i) smaller herring and all size classes of sprat are strictly zooplanktivorous, selecting principally Temora longicornis and Bosmina maritima during the autumn and Pseudocalanus elongatus in winter; (ii) larger herring are essentially nektobenthos feeders, predating on Mysis mixta during the autumn and amphipods and polychaetes during the winter; and (iii) herring and sprat seem to avoid Acartia spp. in both autumn and winter. During the autumn, herring are zooplanktivorous up to 18e20 cm, whereas in winter herring feed on nektobenthos starting from 14e15 cm. Selectivity was not an absolute process but it was related to prey relative abundance in the sea and, possibly, to prey profitability (e.g. size, conspicuousness, and reaction time).
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the influence of biotic and abiotic factors on the growth of sprat Sprattus Sprattus in the baltic sea
Aquatic Living Resources, 2002Co-Authors: Massimiliano Cardinale, Michele Casini, Fredrik ArrheniusAbstract:Abstract We analysed spatial and temporal patterns of condition factor (CF) of sprat (Sprattus Sprattus) between 1986 and 2000 in different areas of the Baltic proper. Results showed a moderate increase in CF between 1986 and 1989. Afterwards, an abrupt decrease in CF, between 22% and 29%, occurred in all the areas of the Baltic proper. However, from 1998 and onwards, CF increased compared to the previous years. Weight-at-age and CF of Baltic herring showed a similar pattern in the same period. Several factors affecting variability of sprat CF were evaluated. Data showed that sprat CF was density-dependent and possibly related to the pelagic fish abundance and individual food intake. Temperature did not influence sprat CF while salinity seemed to affect variability of sprat CF in the northern Baltic proper. Changes in salinity levels may shape pelagic fish growth rates both indirectly changing the zooplankton community structure and abundance and/or directly via fish physiology and metabolisms.
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diet composition and food selectivity of 0 group herring clupea harengus l and sprat Sprattus Sprattus l in the northern baltic sea
Ices Journal of Marine Science, 1996Co-Authors: Fredrik ArrheniusAbstract:Diet composition and prey selectivity of the major Baltic Sea zooplanktivores, 0-group herring (Clupea harengus) and sprat (Sprattus Sprattus), were studied in a coastal area. Diets were dominated by zooplankton, mainly cladocerans (Bosmina longispina maritima and Pleopsis polyphemoides) and copepods (Acartia spp. and Eurytemora aYnis hirundoides/Temora longicornis). There were diVerences in order of the prey selected by the two diVerent 0-group predators (fish hatched during the sampling year) when analysing each species separately. The general order of prey preference for herring was Acartia>Eurytemora>cladocerans>Pseudocalanus minutus>copepod nauplii and for sprat Eurytemora>cladocerans>Acartia>Pseudocalanus>copepod nauplii. As they grew 0-group clupeoids selected larger prey; the greatest preference was shown for intermediate sized prey (0.7‐1.0 mm in cephalothorax length). ? 1996 International Council for the Exploration of the Sea
