682
of long-term data. However, past information is scarce and consistency is a hesitation, especially for changeable and heterogeneous environments as estuaries.
Reports of estuarine landings is a difficult task at short-term. However, it must be
initiated as soon as possible, since estuaries are acknowledged as one of the most
productive marine environments and, at the same time probably the most degraded
coastal settings (Beck et al. 2001; Blaber 2002; Blaber and Barletta 2016; Costa and
Barletta 2016). If proper use should guarantee their sustainability, working with
fisheries ecology and management, a type of use that will demand better levels of
water and surrounding land quality, could be an interesting strategy towards quickly
achieving larger nature conservation goals.
Long-term data on daily production of estuarine resources by habitat would be
important to accurately design analytical assessment models. These models are necessary to understand variations in fish production using coefficients of fishing mortality rates and initial age/length of captures in order to indicate the moment a
resource is available for capture, or when it should be spared (King 2007; Castello
et al. 2009). Precocious captures (juvenile stages) and intense exploitation difficult
a sufficient number of individual to reach an ideal weight to be recruited into adult
stocks and reproduce (King 2007). The theoretical maximum sustainable production is the intersection between optimal values of fishing captures and initial age/
length of capture, and help determining the legal possible length of capture close to
the average length of first maturity (L 50 ). This could be sufficient to consider a fish
stock legally protected by regulatory measures (King 2007; Longhurst 2010). The
main idea is to guarantee that each individual can have the chance to reproduce at
least once, hopefully generating new recruits to adult stocks.
Most studies are focused on a total number of fishes without concerning to the
importance of estuarine habitats for their different developmental stages (larvae,
juvenile, sub-adults and adults), and this is also true for fisheries stats (Dantas et al.
2010; Lima et al. 2015, 2016; MPA 2011). Ontogenetic approaches are important to
understanding the nursery function of estuaries and their habitats for the early stages
of fishing resources that depend on estuaries, partial or totally, to complete their life
cycle (Beck et al. 2001; Able 2005; Ferreira et al. 2016). The natural and expected
environmental variability of estuaries provides specific seasonal abiotic settings at
each habitat, guaranteeing that specific water physico-chemical conditions available
for different life stages at the right time and space. Failure to determine patterns of
habitat uses by different resources makes it challenging to assess the likely consequences of fisheries management actions, such as adjustments on fishing harvest,
changes in gear uses and regulations and the establishment of moratoria on fishing
(Lackey 2005).
Studies about commercial and subsistence fish species which use estuaries and
adjacent coastal waters of Brazilian coasts have provided information on the L 50 for
common snook (Dantas and Barletta 2016), acoupa weakfish (Ferreira et al. 2016),
mojarras (Ramos et al. 2016), drums (Stellifer brasiliensis and S. stellifer) (Dantas
et al. 2015), and catfishes (Dantas et al. 2010). However, selectivity of fishing gears,
if any, varies widely among estuaries. Therefore, fishes that have not reached legal
M. Barletta et al.
of long-term data. However, past information is scarce and consistency is a hesitation, especially for changeable and heterogeneous environments as estuaries.
Reports of estuarine landings is a difficult task at short-term. However, it must be
initiated as soon as possible, since estuaries are acknowledged as one of the most
productive marine environments and, at the same time probably the most degraded
coastal settings (Beck et al. 2001; Blaber 2002; Blaber and Barletta 2016; Costa and
Barletta 2016). If proper use should guarantee their sustainability, working with
fisheries ecology and management, a type of use that will demand better levels of
water and surrounding land quality, could be an interesting strategy towards quickly
achieving larger nature conservation goals.
Long-term data on daily production of estuarine resources by habitat would be
important to accurately design analytical assessment models. These models are necessary to understand variations in fish production using coefficients of fishing mortality rates and initial age/length of captures in order to indicate the moment a
resource is available for capture, or when it should be spared (King 2007; Castello
et al. 2009). Precocious captures (juvenile stages) and intense exploitation difficult
a sufficient number of individual to reach an ideal weight to be recruited into adult
stocks and reproduce (King 2007). The theoretical maximum sustainable production is the intersection between optimal values of fishing captures and initial age/
length of capture, and help determining the legal possible length of capture close to
the average length of first maturity (L 50 ). This could be sufficient to consider a fish
stock legally protected by regulatory measures (King 2007; Longhurst 2010). The
main idea is to guarantee that each individual can have the chance to reproduce at
least once, hopefully generating new recruits to adult stocks.
Most studies are focused on a total number of fishes without concerning to the
importance of estuarine habitats for their different developmental stages (larvae,
juvenile, sub-adults and adults), and this is also true for fisheries stats (Dantas et al.
2010; Lima et al. 2015, 2016; MPA 2011). Ontogenetic approaches are important to
understanding the nursery function of estuaries and their habitats for the early stages
of fishing resources that depend on estuaries, partial or totally, to complete their life
cycle (Beck et al. 2001; Able 2005; Ferreira et al. 2016). The natural and expected
environmental variability of estuaries provides specific seasonal abiotic settings at
each habitat, guaranteeing that specific water physico-chemical conditions available
for different life stages at the right time and space. Failure to determine patterns of
habitat uses by different resources makes it challenging to assess the likely consequences of fisheries management actions, such as adjustments on fishing harvest,
changes in gear uses and regulations and the establishment of moratoria on fishing
(Lackey 2005).
Studies about commercial and subsistence fish species which use estuaries and
adjacent coastal waters of Brazilian coasts have provided information on the L 50 for
common snook (Dantas and Barletta 2016), acoupa weakfish (Ferreira et al. 2016),
mojarras (Ramos et al. 2016), drums (Stellifer brasiliensis and S. stellifer) (Dantas
et al. 2015), and catfishes (Dantas et al. 2010). However, selectivity of fishing gears,
if any, varies widely among estuaries. Therefore, fishes that have not reached legal
M. Barletta et al.