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Reproductive traits and growth of Labrus bergylta in Galician waters
David Villegas-Ríos, Alexandre Alonso-Fernandez, Mariña Fabeiro, Rosario Domínguez-Petit and Fran Saborido-Rey
INTRODUCTION
Galicia and artisanal fishing
· 6000 small boats· Multispecific· Different gears (nets, traps, hooklines)· Weak scientific knowledge· Conflict with habitats
Year
1998 2000 2002 2004 2006 2008
To
ns/
yea
r
0
50
100
150
200
250
300
Landings in Galicia
Col 1 vs Vigo
Landings of Labrus bergylta
Landings in Galicia
Landings in Vigo
INTRODUCTION
Labrus bergylta (ballan wrasse)
· Labridae
· Distribution: NE Atlantic and Mediteranean
· Inhabits rocky reefs from 0 to 60 m
· Feeds on crustacea, molusca, algae and small fish
· Very different patterns of coloration
INTRODUCTION
Reproduction· Protogynic hermaphrodite
· Harem forming
· Benthic eggs and parental care
· Spawns from April to June in Norway
Growth· Old studies
· Based on opercular bones and scales
· 25/29 maximum age for females/males
Coloration
Non mottled colorationMaragota
3€/kg
Mottled colorationPinto6€/kg
INTRODUCTION
METHODS
Sampling· Fish markets· 815 individuals from November 2009 to October 2010· 626 females, 78 males, 107 transitions*· 571 maragota (non mottled coloration), 244 pinto (mottled coloration)· Artisanal fishing: gillnets
Fish markets
METHODS
Sampling
Biometry, coloration
Reproduction Bioenergetics Diet Growth
Formaline -80ºC -20ºC
Ovary OvaryTesticles Testicles Liver Muscle Stomach Otolith
METHODS
Histology
Brown Peterson et al., 2011
· Embebded in parafin
· Haematoxilin-eosin
· 3 micrometresPrimary growth Cortical alveoli Vitellogenesis 1
Vitellogenesis 2 Vitellogenesis 3 Migratory nucleus
Hydratation POFs Atresia
METHODS
Growth
· Sagittae otoliths
· Extracted and washed with freshwater
· Reading of the whole otolith submerged in mineral oil
· Reflected light
· Binocular
3 yr7 yr
15 yr
Reproductive cycle
Month
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Pe
rcen
tage
0
20
40
60
80
100
GS
I
0
1
2
3
4
5
K
1.54
1.56
1.58
1.60
1.62
1.64
1.66
1.68
1.70
1.72
1.74
Spawning Capable Developing Regenerating Regressing GSIK
RESULTS
Reproductive cycle in GaliciaSpawning Capable Developing Regenerating Regressing GSIK
RESULTS
Maturity ogive (length)
L50=23.3 cmL50=23.4 cm L50=24.9 cm
Df Deviance Resid. Df Resid. Dev P(>|Chi|)NULL 503 198.92talla 1 60.75 502 138.18 6.489e-15 ***color 1 16.35 501 121.82 5.257e-05 ***talla:color 1 4.89 500 116.94 0.02706 *
RESULTS
A50=2.7 yr
Df Deviance Resid. Df Resid. Dev P(>|Chi|)
NULL 234 127.076talla 1 36.743 233 90.334 1.348e-09 ***
color 1 0.974 232 89.359 0.32361
talla:color 1 2.802 231 86.557 0.09415 .
Maturity ogive (age)
RESULTS
L50=43.9 cm L50=38.4 cm L50=47.7 cm
Df Deviance Resid. Df Resid. Dev P(>|Chi|)NULL 684 481.59talla 1 69.94 683 411.64 2e-16 ***color 1 96.87 682 314.77 <2e-16 ***talla:color 1 1.43 681 313.35 0.2322
Sex change ogive (length)
RESULTS
A50=10.7 yr
A50=10.5 yr A50=11.5 yr
Df Deviance Resid. Df Resid. Dev P(>|Chi|)NULL 414 284.88talla 1 133.09 413 151.79 < 2.2e-16 ***
color 1 11.72 412 140.07<0.000618
***talla:color 1 3.99 411 136.08 0.045771 *
Sex change ogive (age)
RESULTS
K=0.31 Linf=37.8 T0=-1.48
Growth: Von Bertalanffy ModelL=Linf*(1-exp(-k*(T-T0)))
RESULTS
K=0.31 Linf=37.8 T0=-1.48
Chow testF=51.2
P<0.001
Km=0.38 Linfm=36.3 T0m=-0.65
Kp=0.06 Linfp=62.5 T0p=-7.85
Growth: Von Bertalanffy ModelL=Linf*(1-exp(-k*(T-T0)))
RESULTS
Km=0.38 Linfm=36.3 T0m=-0.65
Growth: Von Bertalanffy ModelL=Linf*(1-exp(-k*(T-T0)))
Kp=0.06 Linfp=62.5 T0p=-7.85
RESULTS
Growth: otolith sizeEstimate Std. Error t value Pr(>|t|)
(Intercept) 0.58 0.22 2.61 0.00959 **talla 0.14 0.01 21.14 < 2e-16 ***colorpinto 0.57 0.33 1.69 0.09200 .talla:colorpinto -0.03 0.01 -3.01 0.00286 **
Fish length - Otolith wideFish length - Otolith length
Estimate Std. Error t value Pr(>|t|)(Intercept) 0.16 0.15 1.07 0.29talla 0.07 0.00 16.58 < 2e-16 ***colorpinto 0.45 0.22 2.03 0.043030 *talla:colorpinto -0.02 0.01 -3.39 0.000816 ***
DISCUSSION
Labrus bergylta spawns in January-April in Galicia, two months earlier than in Norway (Muncaster et al., 2010) and in synchronization with the main upwelling event in the region, just before the first phytoplanckton bloom.
Maturity is reached at 23.4 cm / 2.7 yr, what is above the minimum legal size of capture (20 cm).
Sex change occurs at 43.9 cm/10.7 yr, but there is a great range. Sex Length range
(cm) Age range
(yr)
Female 19.6 – 46.2 2 - 14
Transition 25.5 – 53 2 - 13
Male 28.9 - 51.8 6 - 21
Growth: Labrus bergylta is a slow growth species.
Phytoplanckton blooms in Galicia
DISCUSSION
Does growth rate affect reproductive potential?GSI
Month
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
GS
I
0
1
2
3
4
5
6
7
MaragotaPinto
Labrus bergylta is present in two patterns of coloration. The mottled pattern growths faster, what implies a bigger size at maturity and sex change.
MaragotaPinto
Non mottled
Mottled
