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Miguel Bao - One of the best experts on this subject based on the ideXlab platform.

  • anisakis infection in allis Shad alosa alosa linnaeus 1758 and twaite Shad alosa fallax lacepede 1803 from western iberian peninsula rivers zoonotic and ecological implications
    Parasitology Research, 2015
    Co-Authors: Miguel Bao, Micaela Mota, David Jose Nachon, Carlos Antunes, Fernando Cobo, Manuel E Garci, Graham J Pierce, Santiago Pascual
    Abstract:

    Spawning individuals of allis Shad, Alosa alosa (Linnaeus, 1758), and twaite Shad, Alosa fallax (Lacepede, 1803), were sampled from three rivers on the Atlantic coast of the Iberian Peninsula (Ulla, Minho, Mondego) during 2008 to 2013 to assess the presence of the zoonotic marine parasite Anisakis spp. larvae. The results revealed that both Shad species were infected by third-larval stage Anisakis simplex s.s. and Anisakis pegreffii. The latter is reported in mixed infections in both Shad species of Western Iberian Peninsula for the first time. In A. alosa, the prevalence of Anisakis infection can reach 100%, while in A. fallax, prevalence was up to 83%. Infected individuals of the former species also often contain much higher number of parasites in theirs internal organs and flesh: from 1 to 1138 Anisakis spp. larvae as compared to 1 to 121 larvae, respectively. In general, numbers of A. pegreffii were higher than those of A. simplex s.s. Our results suggest that in the marine environment of the Western Iberian Peninsula, both anadromous Shad species act as paratenic hosts for A. simplex s.s. and A. pegreffii, thus widening the distribution of the infective nematode larvae from the marine to the freshwater ecosystem. This finding is of great epidemiological relevance for wildlife managers and consumers, considering the zoonotic and gastroallergic threats posed of these parasites.

Roy A Stein - One of the best experts on this subject based on the ideXlab platform.

  • nutrient cycling by fish supports relatively more primary production as lake productivity increases
    Ecology, 2006
    Co-Authors: Michael J Vanni, Anna M Bowling, Elizabeth M Dickman, Scott R Hale, Karen A Higgins, Martin J Horgan, Lesley B Knoll, William H Renwick, Roy A Stein
    Abstract:

    Animals can be important in nutrient cycling in particular ecosystems, but few studies have examined how this importance varies along environmental gradients. In this study we quantified the nutrient cycling role of an abundant detritivorous fish species, the gizzard Shad (Dorosoma cepedianum), in reservoir ecosystems along a gradient of ecosystem productivity. Gizzard Shad feed mostly on sediment detritus and excrete sediment-derived nutrients into the water column, thereby mediating a cross-habitat translocation of nutrients to phytoplankton. We quantified nitrogen and phosphorus cycling (excretion) rates of gizzard Shad, as well as nutrient demand by phytoplankton, in seven lakes over a four-year period (16 lake-years). The lakes span a gradient of watershed land use (the relative amounts of land used for agriculture vs. forest) and productivity. As the watersheds of these lakes became increasingly dominated by agricultural land, primary production rates, lake trophic state indicators (total phosphorus and chlorophyll concentrations), and nutrient flux through gizzard Shad populations all increased. Nutrient cycling by gizzard Shad supported a substantial proportion of primary production in these ecosystems, and this proportion increased as watershed agriculture (and ecosystem productivity) increased. In the four productive lakes with agricultural watersheds (.78% agricultural land), gizzard Shad supported on average 51% of phytoplankton primary production (range 27-67%). In contrast, in the three relatively unproductive lakes in forested or mixed-land-use watersheds (.47% forest, ,52% agricultural land), gizzard Shad supported 18% of primary production (range 14-23%). Thus, along a gradient of forested to agricultural landscapes, both watershed nutrient inputs and nutrient translocation by gizzard Shad increase, but our data indicate that the importance of nutrient translocation by gizzard Shad increases more rapidly. Our results therefore support the hypothesis that watersheds and gizzard Shad jointly regulate primary production in reservoir ecosystems.

  • linking bluegill and gizzard Shad prey assemblages to growth of age 0 largemouth bass in reservoirs
    Transactions of The American Fisheries Society, 1998
    Co-Authors: James E Garvey, Roy A Stein
    Abstract:

    Abstract Either gizzard Shad Dorosoma cepedianum or bluegills Lepomis macrochirus dominate prey assemblages in many small (<100 ha) Ohio reservoirs. Because gizzard Shad spawn early in the spring and their offspring grow rapidly, age-0 gizzard Shad may be invulnerable to age-0 largemouth bass Micropterus salmoides thereby compromising this piscivore's growth and, potentially, recruitment. To test this hypothesis, we quantified growth, abundance, and diets of age-0 largemouth bass in reservoirs dominated by age-0 bluegills (one reservoir) or age-0 gizzard Shad (two reservoirs) during June through early October 1992–1994. In the bluegill-dominated reservoir, age-0 largemouth bass grew slowly (about 0.04 g/d) during June through mid-August. Though age-0 bluegills became abundant after mid-August, contributing to rapid growth (about 0.2 g/d) of age-0 largemouth bass, these age-0 largemouth bass only reached small to moderate sizes by fall (range of mean wet weights, 3–7 g). In the reservoirs dominated by gizz...

  • nitrogen and phosphorus excretion by detritivorous gizzard Shad in a reservoir ecosystem
    Limnology and Oceanography, 1997
    Co-Authors: Maynard H Schaus, Michael J Vanni, T E Wissing, Mary T Bremigan, James E Garvey, Roy A Stein
    Abstract:

    The detritivorous fish, gizzard Shad (Dorosoma cepedianum), provides nutrients to phytoplankton in reservoirs by ingesting organic detritus associated with sediments and excreting substantial quantities of nutrients such as N and P in soluble forms that are highly available to phytoplankton, We estimated nutrient excretion by gizzard Shad in a eutrophic reservoir (Acton Lake, Ohio) during April-October 1994 by measuring N and P excretion of fieldcaught fish (n = 135). Excretion rates were then extrapolated to nutrient release by the gizzard Shad population using quadrat rotenone biomass estimates, electrofishing surveys, and historic seasonal trends. N and P excretion were positively correlated with fish wet mass and temperature, but mass-specific excretion declined with increasing fish mass. Lakewidc gizzard Shad biomass in July 1994 was 417 kg ha -I, Our estimates of nutrient excretion by the gizzard Shad population ranged from 0.487 to 0.769 pmol NH,-N liter-’ d-l and 0.022 to 0.057 pmol soluble reactive phosphorus liter -I d .I, with the highest excretion occurring during mid-summer through early fall. The low N : P ratio at which gizzard Shad excrete [mean molar N : P = 16.75 (kO.89 SE)] may alter phytoplankton community composition, favoring cyanobacteria. Our results indicate that nutrient excretion by detritivorous fish can be an important source of nutrients to open waters, especially when other sources of nutrients are reduced.

  • feeding preferences of omnivorous gizzard Shad as influenced by fish size and zooplankton density
    Transactions of The American Fisheries Society, 1996
    Co-Authors: Lisa A Yako, John M Dettmers, Roy A Stein
    Abstract:

    Abstract In Ohio reservoirs, larval gizzard Shad Dorosoma cepedianum less than 30 mm total length consume only zooplankton but frequently switch to detritus as they grow longer than 30 mm. However, in laboratory studies without detritus, gizzard Shad longer than 30 mm consume crustacean zooplankton. To explore the composition of diets of omnivorous 30–100-mm gizzard Shad, we completed 1-h laboratory feeding trials with different amounts of zooplankton and detritus and quantified the diets of gizzard Shad in reservoirs. In both laboratory and field, gizzard Shad ate primarily detritus but also ate zooplankton, consuming more as more became available, which demonstrates that this species is a facultative detritivore. In the field, zooplankton consumption declined as gizzard Shad body size increased. We believe gizzard Shad maximize growth by supplementing their low-protein detritus diet with more zooplankton as more becomes available. With this strategy, omnivorous gizzard Shad may compromise the potential ...

  • quantifying responses to hybrid striped bass predation across multiple trophic levels implications for reservoir biomanipulation
    Transactions of The American Fisheries Society, 1996
    Co-Authors: John M Dettmers, Dennis R. Devries, Roy A Stein
    Abstract:

    Abstract Top-down effects from piscivores to phytoplankton have been documented in north temperate lakes, thus permitting managers to regulate these food webs. From our review of the literature, reservoir trophic interactions appear less amenable to biomanipulation owing to the presence of a fast-growing, omnivorous planktivore, gizzard Shad Dorosoma cepedianum. If reservoir zooplankton can be enhanced by reducing gizzard Shad through biomanipulation, this could increase survival of food-limited early life stages of sport fishes dependent on zooplankton and could improve water clarity by reducing phytoplankton. To quantify this potential, we evaluated responses of age-0 gizzard Shad, crustacean zooplankton, and phytoplankton to the addition of hybrid striped bass Morone saxatilis × M. chrysops (22 kg/ha) to four of eight 0.4-ha ponds. Hybrid striped bass nearly eliminated age-0 gizzard Shad from ponds within 10 d after being stocked, which permitted zooplankton density and size to increase but had no effe...

Santiago Pascual - One of the best experts on this subject based on the ideXlab platform.

  • anisakis infection in allis Shad alosa alosa linnaeus 1758 and twaite Shad alosa fallax lacepede 1803 from western iberian peninsula rivers zoonotic and ecological implications
    Parasitology Research, 2015
    Co-Authors: Miguel Bao, Micaela Mota, David Jose Nachon, Carlos Antunes, Fernando Cobo, Manuel E Garci, Graham J Pierce, Santiago Pascual
    Abstract:

    Spawning individuals of allis Shad, Alosa alosa (Linnaeus, 1758), and twaite Shad, Alosa fallax (Lacepede, 1803), were sampled from three rivers on the Atlantic coast of the Iberian Peninsula (Ulla, Minho, Mondego) during 2008 to 2013 to assess the presence of the zoonotic marine parasite Anisakis spp. larvae. The results revealed that both Shad species were infected by third-larval stage Anisakis simplex s.s. and Anisakis pegreffii. The latter is reported in mixed infections in both Shad species of Western Iberian Peninsula for the first time. In A. alosa, the prevalence of Anisakis infection can reach 100%, while in A. fallax, prevalence was up to 83%. Infected individuals of the former species also often contain much higher number of parasites in theirs internal organs and flesh: from 1 to 1138 Anisakis spp. larvae as compared to 1 to 121 larvae, respectively. In general, numbers of A. pegreffii were higher than those of A. simplex s.s. Our results suggest that in the marine environment of the Western Iberian Peninsula, both anadromous Shad species act as paratenic hosts for A. simplex s.s. and A. pegreffii, thus widening the distribution of the infective nematode larvae from the marine to the freshwater ecosystem. This finding is of great epidemiological relevance for wildlife managers and consumers, considering the zoonotic and gastroallergic threats posed of these parasites.

Graham J Pierce - One of the best experts on this subject based on the ideXlab platform.

  • anisakis infection in allis Shad alosa alosa linnaeus 1758 and twaite Shad alosa fallax lacepede 1803 from western iberian peninsula rivers zoonotic and ecological implications
    Parasitology Research, 2015
    Co-Authors: Miguel Bao, Micaela Mota, David Jose Nachon, Carlos Antunes, Fernando Cobo, Manuel E Garci, Graham J Pierce, Santiago Pascual
    Abstract:

    Spawning individuals of allis Shad, Alosa alosa (Linnaeus, 1758), and twaite Shad, Alosa fallax (Lacepede, 1803), were sampled from three rivers on the Atlantic coast of the Iberian Peninsula (Ulla, Minho, Mondego) during 2008 to 2013 to assess the presence of the zoonotic marine parasite Anisakis spp. larvae. The results revealed that both Shad species were infected by third-larval stage Anisakis simplex s.s. and Anisakis pegreffii. The latter is reported in mixed infections in both Shad species of Western Iberian Peninsula for the first time. In A. alosa, the prevalence of Anisakis infection can reach 100%, while in A. fallax, prevalence was up to 83%. Infected individuals of the former species also often contain much higher number of parasites in theirs internal organs and flesh: from 1 to 1138 Anisakis spp. larvae as compared to 1 to 121 larvae, respectively. In general, numbers of A. pegreffii were higher than those of A. simplex s.s. Our results suggest that in the marine environment of the Western Iberian Peninsula, both anadromous Shad species act as paratenic hosts for A. simplex s.s. and A. pegreffii, thus widening the distribution of the infective nematode larvae from the marine to the freshwater ecosystem. This finding is of great epidemiological relevance for wildlife managers and consumers, considering the zoonotic and gastroallergic threats posed of these parasites.

William K Roche - One of the best experts on this subject based on the ideXlab platform.

  • a species to be the genetic status and colonization history of the critically endangered killarney Shad
    Molecular Phylogenetics and Evolution, 2013
    Co-Authors: James J King, William K Roche, Ilaria Coscia, Allan D Mcdevitt, Carol Mcloughlin, Stefano Mariani
    Abstract:

    Typically anadromous, the twaite Shad (Alosa fallax) can become landlocked and adapt to a fully freshwater life. The only landlocked Shad population in Northwestern Europe is found in a lake in Ireland, Lough Leane. The Killarney Shad, Alosa killarnensis (or Alosa fallax killarnensis, as it is mostly referred to) displays a level of morphological divergence that indicates a long-term isolation in the lake. Microsatellites and mtDNA control region sequences were used within a coalescent framework (BEAST and Approximate Bayesian Computation (ABC)) to investigate its colonization history and to clarify its taxonomic status. Results indicate that the lake was likely colonized in two independent events, the first coinciding with the retreat of the ice sheet from the area after the Last Glacial Maximum and the second after the Younger Dryas. Microsatellite data has shown that these two landlocked lineages have completely admixed within the lake, and have started diverging significantly from their closest ancestor, the twaite Shad. We argue that our molecular results (together with the life-history and physiological divergence between Killarney and twaite Shad) are conspicuous enough to view the landlocked population as a new species, and one whose future existence would certainly not be insured by its sister taxon.

  • aspects of anadromous allis Shad alosa alosa linnaeus and twaite Shad alosa fallax lacepede biology in four irish special areas of conservation sacs status spawning indications and implications for conservation designation
    Hydrobiologia, 2008
    Co-Authors: James J King, William K Roche
    Abstract:

    Four Special Areas of Conservation (SACs) have been designated in the Republic of Ireland for Twaite Shad, Alosa fallax (Lacepede), based on recent historical information on spawning activity—the estuarine reaches of the Rivers Munster Blackwater, Suir, Barrow–Nore and Slaney. The spawning status of some of these populations is considered to have declined substantially in recent years, and no known spawning areas of Allis Shad, Alosa alosa (L.), are known for Ireland. Data are presented confirming the presence of both Allis Shad and Twaite Shad in all four SACs. The majority of the material has come as by-catch from estuarine commercial salmon netsmen. Angling is the principal source of material from the R. Barrow. Examination of scale and gonad material of Allis Shad indicates some degree of readiness for spawning as well as spawning having taken place. Gonadosomatic index (GSI) data from the R. Barrow for Twaite Shad in the May spawning period (2000–2002) had mean GSIs of 13.7–15% with maxima in the range of 21–28%. GSI values of 18% and 22% have been recorded in the July period for individual Allis Shad from the upper estuaries of the R. Slaney and R. Suir, respectively, with both fish displaying gonad maturity stage V or VI (after Pina, 2000). Low GSI values have been recorded from other Allis Shad in the June–July period displaying gonad condition varying from stage III (immature) to stage VIII (spent). These findings point to a possibility that Allis Shad do engage in spawning activity, whether mono-specifically or with Twaite Shad. The possibility of the latter is supported by gill raker count data presented. These show clearly defined value ranges for Twaite and for Allis as well as a series of fish with intermediate counts. The apparently low population levels of Twaite Shad within the SACs identify a need to examine what measures might be undertaken to ensure the favourable conservation status of this species.