نتایج جستجو برای: spawning effectiveness

تعداد نتایج: 329732  

2008
James M. Helfield Robert J. Naiman JAMES M. HELFIELD

Anadromous Pacific salmon (Oncorhynchus spp.) transport marine-derived nitrogen (MDN) to the rivers in which they reproduce. Isotopic analyses indicate that trees and shrubs near spawning streams derive -22-2492 of their foliar nitrogen (N) from spawning salmon. As a consequence of this nutrient subsidy, growth rates are significantly increased in Sitka spruce (Picea sitchensis) near spawning s...

2012
Sebastian Schmidt-Roach Karen J. Miller Erika Woolsey Gabriele Gerlach Andrew H. Baird

The coral genus Pocillopora is one of the few to include some species that broadcast spawn gametes and some species that brood larvae, although reports of reproductive mode and timing vary within and among species across their range. Notably, the ubiquitous Pocillopora damicornis has been described as both a brooder and spawner, although evidence of broadcast spawning is rare. Here, we report o...

2016
James Gilmour Conrad W. Speed Russ Babcock

Larval production and recruitment underpin the maintenance of coral populations, but these early life history stages are vulnerable to extreme variation in physical conditions. Environmental managers aim to minimise human impacts during significant periods of larval production and recruitment on reefs, but doing so requires knowledge of the modes and timing of coral reproduction. Most corals ar...

Journal: :Journal of fish biology 2010
J R Gold M A Renshaw E Saillant R R Vega

Parentage analysis, employing five hypervariable microsatellite markers, was used to follow spawning patterns of red drum Sciaenops ocellatus broodfish in two spawning tanks through most of a calendar year in a marine fish hatchery dedicated to stock enhancement. Five of six dams and all four sires spawned at least once during the year. Variation in dam and sire spawning incidence and in number...

2014
Andrew H. Baird David Abrego Emily J. Howells Vivian R. Cumbo Bert Hoeksema Jean Kenyon Andrew Baird

Determining when corals reproduce has clear management and economic implications. Here we document the reproductive condition of corals in the genus Acropora on the island of Socotra in Yemen during February 2014. Twenty percent of colonies (n = 143) contained mature gametes and 28% had immature gametes indicating that spawning will occur in both February and March in 2014, confirming previous ...

1995

Reproduction in fishes is regulated by external environmental factors that trigger internal mechanisms into action. The final event of the reproductive cycle, the release of eggs and sperm resulting in spawning, can be controlled by either placing the fish in an appropriate environment or by changing the fish’s internal regulating factors with injected hormones or other substances. The internal...

2015
Timothy J. Sullivan Carol A. Stepien

This study tested the hypothesis that the genetic composition of Yellow Perch Perca flavescens spawning groups at specific sites remained consistent among years or age-cohorts; this likely would influence spatial population structure and be important for delineating management units. Previous studies identified that spawning groups genetically differed among locations across fine geographic sca...

2002
Michael K. Young Thomas A. Wesche Wayne A. Hubert MICHAEL K. YOUNG A. WESCHE

-To measure the changes in substrate composition produced by spawning brook trout Salvefinus fontinalis, we collected 187 freeze-core samples, both before and after spawning, from egg pockets, inside redds but excluding egg pockets, and outside redds. In the upper strata of reddassociated samples, we found that the proportions of particles 0.85-1.70,0.425-0.85,0.2 12-0.425, and less than 0.212 ...

2016
David Righton Håkan Westerberg Eric Feunteun Finn Økland Patrick Gargan Elsa Amilhat Julian Metcalfe Javier Lobon-Cervia Niklas Sjöberg Janek Simon Anthony Acou Marisa Vedor Alan Walker Thomas Trancart Uwe Brämick Kim Aarestrup

The spawning migration of the European eel (Anguilla anguilla L.) to the Sargasso Sea is one of the greatest animal migrations. However, the duration and route of the migration remain uncertain. Using fishery data from 20 rivers across Europe, we show that most eels begin their oceanic migration between August and December. We used electronic tagging techniques to map the oceanic migration from...

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