C1
Does that tidal range account also for meteorological tides ?
R
Tides in the Mediterranean Sea are semi-diurnal in nature. This tide range
account for a semidiurnal tides associated with meteorological forcing.
C2
Any reference support for the presence of Posidonia ? What do you mean by high
densities? Root density?
R
- It's the same reference mentioned at the end of the paragraph, (Brahim et al,
2003).
- The densities of Posidonia are usually measured by shoots /m². Please see lines
81-88
C3
It would be nice to have references to a figure depicting the currents. You can easily
add them to Fig.1 I guess.
R
I think if we add the current circulation, the figure loses its main objective,
which is the presentation of the study area.
The problem is that the most important events of water circulation occur
outside of the study area, near the Lampedusa island and over the isobath
200m.
On the other hand the circulation pattern over the continental shelf of the gulf
still poorly informed and the state of knowledge on ATC variability is still
fragmented, so we cannot depict it in this figure .please see our attempt in the
figure below
C4
Paragraphs. In general, there are too many separate paragraphs, some of them
containing only one sentence. I would try to make longer paragraphs that condensed
different themes.
R
Please see Lines from 103 to 111.
C5
I do not understand the relation between the first two objectives and this « tuna »
one. I understand that actually there are studies on tuna larvae in the area (Koched et
al). If so, then this latter objective does not make sense. Are those studies performed
in distant areas from the Gulf of Gabes ?
R
I replaced “tuna” by “larval” it makes more sense. Please see lines 146 -147
C6
Pore size?
R
1.2µm. line 161
C7
Were the samples taken both during day and night ? If not, no problem. If so, was
the time of the day incorporated somehow as an explanatory variable ?
R
Samples are taken only during the day.
C8
It is more useful to give the average (and SD) filtered volume and the average time.
R
Please see lines 166 - 167
C9
Did you also fit flow meters to the small bongos?
R
Yes, all bongos were fitted with flow meters.
C10
Brand?
R
Jenway model 6405UV/Visible. Please see line 181
C11
Although it is usual to report zooplankton concentrations in per-volume units, do
you think it makes sense to use surface-based larval units and volume-based
zooplankton units?
R
I think, your comment will be right when we do a direct comparison between
fish larvae density and zooplankton biomass.
But here we only interest on the correlation sense between this factor
(zooplankton biomass measured as dry weight) and larvae density.
In other words, in this study we used the zooplankton biomass as biotic
parameter like the CH a, and the unit of the both factors is mg/m3.
On the other hand previous studies have report zooplankton biomass per
volume unit and larvae density per surface unit, please see Alemany et al 2010,
Giordano et al 2014 etc….
In the present study we used surface
SMITH&RICHARDSON 1977 methodology.
units
according
to
C12
Would the Euclidean distance not be a more appropriate metric for environmental
variables?
R
Yes you’re right it should be Euclidean, and I used Euclidean distance to
establish this HAC. It’s a mistake of writing.
C13
R
I understand that you have different Chla measures for each station. Did you
use a surface value for T,S and Chl a ? Did you integrate them somehow ? It
would have been interesting to include some kind of stratification index.
I used only surface value for all variables.
The stratification index was calculated as the difference in potential density between
the upper 10 m (0–10 m average) and 200 m. But in our case we haven’t any data on
the density
C14
A t what depth ?
R
At the surface line 222
C15
Be careful with Fig. 2, you are interpolating values north of Kerkennah Island, and
you do not have enough stations there to do that. I would not interpolate over
distances >1/2 the between-station distance.
R
Please see the new figs
C16
Fig. 2 is strange : you are using relatively wide T and salinity ranges…I would rather
use the real values at each station, and interporlate using a continuous scale
R
Please see the new figs. I replaced also the others maps (Oxygen, zooplankton
and chlorophylle a).
C17
Beside those graphs, I would show a T-S plot to identify the water masses according
to their combined properties.
R
Please see the T-S plot (Fig 4), and the paragraph line 256 to 272.
C18
I really think that the T-S plot would help disentangling the effect of belonging to a
different water mass and the effect of the higher effects of evaporation at shallow
depths
R
Please see the plot (Fig 4) and the paragraph line 256 to 272..
C19
I guess the relationship between temperature and oxygen here explains
almost all spatial/vertical variation
R
Yes you’re right; the negative effect of temperature on oxygen solubility can
explain the vertical and horizontal variation of dissolved oxygen.
C20
The letters A and B do not show well in those figures
R
Corrected, please see the Figs.
C21
I don’t understand how you can find a high Chl a peak north-west of Kerkennah if
there are no stations there
R
I deleted Kerkennah. Please see line 284, and the new figure.
C22
I would tone-down this, because you are not used a fluorimeter that gives you high
vertical resolution to detect the DCM.
R
Paragraph deleted
C23
You can describe this much easily using a PCA, plus the cluster, because you can
see the vectors over the station groups coming from the cluster. As it is now, the
reader has to look at many maps to believe what you are saying with regard to the
descriptors of the station groups.
R
Please see the biplot (Fig 8)
C24
There is an inconsistency between naming the bullet tune « middle sized » and then
saying that it represents 82% of the large pelagics. Also, in Tabl 1 is not classified as
large pelagic but as midpelagic
R
Large pelagic larval replaced by tuna larval. Please see line 339
C25
Is that not a constrain of the Pielou calculation formula ?
R
Of course the Pielou index is constrained between 0 and 1. And in the present
work, the calculated Pielou’s evenness index was ranged between 0 and 1.
C26
That is a good figure. However, I wonder why are you not using interpolated maps
for larval data, where as you are using them for environmental variables. Any
particular reason ?
R
Please see the new map (Fig 11).
C27
Shouold you not use dot instead of comma throughout ?
R
Corrected, Please see line 382
C28
R
Is this not the part of the variance from another general part (constrained ordination)
explained by the full CCA ? I mean, usually the CCA explains a small fraction of the
whole variance, and the axes explain a large fraction of what the whole CCA
explains…
Yes you're absolutely right. I replaced "the total variance" by "inertia". It
will be more correct I think. Please see line 396.
C29
Axis I is positively correlated with depth, but is Axis II too ?
R
Corrected, please see line 400.
C30
Gentle slope ? softbottom ?
R
Soft slop replaced by flat low slope please see line 421.
C31
Pollutants ?
R
C32
Sorry, I didn’t understand your comment.
But I mean by industrial pollutant the industrial discharge of phosphate, in fact
the coats of the gulf of Gabes concentrates a great number of industrial
activities, mainly related to the industry of phosphates which contributes to the
increase of phosphate concentrations near the coast.
Speculative, as you are not showing any nutrient data. I would advise to either
reference it or tone-down the phrase.
R
I add (Bel Hassen et al., 2009) as reference. Please see line 442.
C33
Or to the oceanographic regime : for example, in the Balearic Islands the water
masses and their dynamics is different from those in the Gulf of Gabes, which may
also induce changes in fish reproductive behaviour and in adult composition. I think
you mention this later in the text.
R
Please see the new paragraph. Please see lines 472 and 473.
C34
I am not sure. If they have broad distributions, they are not masking patterns, it is
just that these patterns do not exist.
R
Phrase deleted
C35
This basically happens through the world
R
Yes it's true, this kind of assemblage is typical through the word. But I would
like to restricted my comparisons on a regional scale
C36
I wonder how much influence do the tides hace in potential transport mechanisms.
Tides are not found generally as an explanatory transport mechanism in the
Mediterranean, so this case is atypical in that sense.
R
I'm not mean by the "mesoscale hydrographic feature" the tide only, but also
the current.
But I think the strong tides that characterized this gulf, can play with currents
a key role in the spatial distribution of larvae.
C37
Please rephrase
R
This may be inferred that the spawning area of these two species (bluefin and
albacore tuna), may be located more towards the open sea. Please see lines 525 to
527.
C38
C39
This not exact. Spawning may occur not necessarily in the shelf break, but over shelf
areas where production and retention excels (in the case of anchovy), but quite
closer to the coast in sardinella….
Sorry, I'm not say necessarily but preferentially. And this explication has been
advanced according to previous studies carried out in the Tunisian waters
(Zarrad et al 2012) and in the other areas of the Mediterranean (Olivar et al
2001, Cuttitta et al 2006, Palomera & Sabatés 1990, Palomera 1992...), which
demonstrate that both anchovy and sardinella larvae more concentrated within
the limits of the continental shelf (near the shelf break), where various kinds of
enrichment process may occur.
rephrase
R
Voir le nouveau paragraphe:
R
"It can be concluded that the horizontal spatial distribution pattern of fish larvae in
this area is significantly linked to the combined effect of two factors; the first one is
the depth gradient, which determined the habitat of spawners and the he second
factor is the mesoscale hydrodynamic features (currents and tides) which modify the
initial fish larvae assemblage distribution".
I would say (or says) in this paragraph, that the spatial distribution of larvae is
the consequence of two factors: the first is depth gradient which determined the
habitat of adults, and the second is the mesoscale hydrodynamic feature which
modify the initial fish larvae assemblage