the extraordinary amplitude of the vertical motions induced by the tidal currents in
the spawning area (Sanchez-Garrido et al. 2011; Garcia-Lafuente et al. 2013) is
capable to position the ELHS at almost any depth in the water column. Therefore,
even though the species is benthopelagic, it cannot be ruled out the ELHS raised to
surface layers and, under the influence of the AJ, be transported toward the Mediterranean. But ELHS can also remain in the lower layer and ending in the Atlantic.
The very energetic hydrodynamics associated with tides makes ELHS available to be
transported in either direction.
12.5.4 Spawning Phenology and Vital Rates
Vital rates at ontogenic development are greatly affected by temperature, which
controls the rate of metabolic processes occurring at ELHS, thereby influencing PLD
of invertebrate and vertebrate marine species (O’Connor et al. 2007). Survival of
ELHSs of fish increases with ontogenic development, whereby greatest mortality
rates occur at earliest stages of development. Most sensitive stages are during the egg
development and lecithotrophic larval development, stages particularly vulnerable to
predation. The egg development in small pelagic species is temperature dependent
and lasts 3-5 days (Miranda et al. 1990; Pepin 1991; Bernal et al. 2001). In addition,
growth is likewise dependent on inherited parental and maternal traits (Green and
McCormick 2005; Uriarte et al. 2016). The maternal and parental influences will
highly depend on the age structure of a determined spawning stock.
Considering the relevance of temperature in controlling metabolic processes,
assessing the change of environmental conditions due to climatic and seasonal
factors over the time span of a determined species’ spawning is of utmost importance. Sardines and anchovies show partial overlapping spawning seasons (Garcia
et al. this book), in which surface temperature from winter to spring can have as
much as a difference of 3-4
C, thereby influencing larval growth strategies. On
average, spring larval cohorts of sardine show less production but they grow
significantly faster due to a higher temperature during development (Garcia et al.
this book).
Despite spawning synchronicity in a species, great environmental differences
may be manifested by the local temperature regime and the production of trophic
resources that originate from hydroclimatic processes. Larval growth rates of the
same small pelagic species can show important differences between regions
(Palomera et al. 2007). It would be the case of sardine or anchovy spawning in the
bays of Malaga and Almeria (Fig. 12.1) in the Alboran Sea (Quintanilla et al. 2017).
Nonetheless, the seasonality of spawning of these species has to be tuned to the
phytoplankton blooms that occur in autumn and spring and trigger zooplankton
production, the main trophic level which larval sardines and anchovies prey upon
(Garcia et al. this book).
From yolk-sac larvae to the end of the preflexion stage, the ELHSs are exposed to
predation and, possibly, to starvation depending on the available feeding resources.
478
J. Garcia-Lafuente et al.
the spawning area (Sanchez-Garrido et al. 2011; Garcia-Lafuente et al. 2013) is
capable to position the ELHS at almost any depth in the water column. Therefore,
even though the species is benthopelagic, it cannot be ruled out the ELHS raised to
surface layers and, under the influence of the AJ, be transported toward the Mediterranean. But ELHS can also remain in the lower layer and ending in the Atlantic.
The very energetic hydrodynamics associated with tides makes ELHS available to be
transported in either direction.
12.5.4 Spawning Phenology and Vital Rates
Vital rates at ontogenic development are greatly affected by temperature, which
controls the rate of metabolic processes occurring at ELHS, thereby influencing PLD
of invertebrate and vertebrate marine species (O’Connor et al. 2007). Survival of
ELHSs of fish increases with ontogenic development, whereby greatest mortality
rates occur at earliest stages of development. Most sensitive stages are during the egg
development and lecithotrophic larval development, stages particularly vulnerable to
predation. The egg development in small pelagic species is temperature dependent
and lasts 3-5 days (Miranda et al. 1990; Pepin 1991; Bernal et al. 2001). In addition,
growth is likewise dependent on inherited parental and maternal traits (Green and
McCormick 2005; Uriarte et al. 2016). The maternal and parental influences will
highly depend on the age structure of a determined spawning stock.
Considering the relevance of temperature in controlling metabolic processes,
assessing the change of environmental conditions due to climatic and seasonal
factors over the time span of a determined species’ spawning is of utmost importance. Sardines and anchovies show partial overlapping spawning seasons (Garcia
et al. this book), in which surface temperature from winter to spring can have as
much as a difference of 3-4
C, thereby influencing larval growth strategies. On
average, spring larval cohorts of sardine show less production but they grow
significantly faster due to a higher temperature during development (Garcia et al.
this book).
Despite spawning synchronicity in a species, great environmental differences
may be manifested by the local temperature regime and the production of trophic
resources that originate from hydroclimatic processes. Larval growth rates of the
same small pelagic species can show important differences between regions
(Palomera et al. 2007). It would be the case of sardine or anchovy spawning in the
bays of Malaga and Almeria (Fig. 12.1) in the Alboran Sea (Quintanilla et al. 2017).
Nonetheless, the seasonality of spawning of these species has to be tuned to the
phytoplankton blooms that occur in autumn and spring and trigger zooplankton
production, the main trophic level which larval sardines and anchovies prey upon
(Garcia et al. this book).
From yolk-sac larvae to the end of the preflexion stage, the ELHSs are exposed to
predation and, possibly, to starvation depending on the available feeding resources.
478
J. Garcia-Lafuente et al.