The Spawning, Embryonic and Early Larval Development of the Green

Animal Reproduction Science 125 (2011) 196–203

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Animal Reproduction Science

journal homepage: www.elsevier.com/locate/anireprosci

The spawning, embryonic and early larval development of the green

wrasse Labrus viridis (Linnaeus, 1758) (Labridae) in controlled conditions

a,∗ a b a a

V. Kozulˇ ,N.Glavic´ ,P. Tutman , J. Bolotin , V. Onofri

Institute for Marine and Coastal Research, P.O. Box 83, 20000 Dubrovnik, Croatia

Institute of Oceanography and Fisheries, 21000 Split, Croatia

a r t i c l e i n f o a b s t r a c t

Article history:

Green wrasse, Labrus viridis (Linnaeus, 1758), is an endangered species in the southern Adri-

Received 21 May 2010

atic Sea, but it is also of interest for potential rearing in polyculture with other commercial

Received in revised form 17 January 2011

species for the repopulation of areas where it is endangered or as a new aquaculture species.

Accepted 24 January 2011

A parental stock of the green wrasse was kept in aquaria for six years. The spawning, embry-

Available online 2 February 2011

onic and early larval development maintained under controlled laboratory conditions are

described and illustrated. The average diameter of newly spawned eggs was 1.01 ± 0.03 mm.

Keywords:

Mature and fertilized eggs were attached to the tank bottom by mucus. Hatching started

Green wrasse ◦

after 127 h at a mean temperature of 14.4 ± 0.8 C. The average total length of newly hatched

Labrus viridis

Spawning larvae was 4.80 0.22 mm. Absorption of the yolk-sac was completed after the 5th day

Eggs when larvae reached 5.87 ± 0.28 mm.

Larvae Larvae were fed with the rotifers Brachionus plicatilis. The pigmentation of L. viridis larvae

Adriatic Sea is similar to that of Labrus merula and Labrus bergylta, but the main differences between

these species are in the size of larvae and the development time of the melanophores on the

anal ﬁn-fold (ﬁve days later than with L. merula) and on top of the head (nine days earlier

than with L. merula).

1. Introduction could still only be caught in the southern Adriatic. The

same data (Onofri, 1975) concerning the endangerment of

Green wrasse, Labrus viridis (Linnaeus, 1758), is an wrasse was noted ten years later, while researching various

endangered species in the southern Adriatic Sea, but it is species of labrids along the eastern shores of the Adriatic.

also of interest for potential rearing in polyculture with It is the only species in Croatian coastal waters whose ﬁsh-

other commercial species for the repopulation of areas ing and trading is permanently banned due to population

where it is endangered or as a new aquaculture species. reductions since 2002 (Directive on the Protection of Fish

Green wrasse is distributed throughout the Mediterranean, and Other Marine Organisms, National Gazette, 101/02,

in the western region of the Black Sea and in the east- 2002). In the time prior to the ban, wrasse was caught at

ern Atlantic from Portugal to Morocco (Quignard and Pras, a rate of about 2 tons of per year along the eastern shores

1986). Quingnard (1966) noted more than 40 years ago that of the Adriatic (Jardas, 1996). There are no available data

the wrasse was a very rare species in the northern Adriatic, on the annual catch of wrasse since the introduction of the

scarcer in the central Adriatic and that larger specimens Directive and up to the present time. During the 1970s, the

largest recorded length of green wrasse was 60 cm (Onofri,

1975), while it decreased to 55 cm in the nineties (Jardas,

∗ 1996). The average catch length 10 years ago was 20–35 cm,

Corresponding author. Tel.: +385 20 323131; fax: +385 20 323872.

E-mail address: [email protected] (V. Kozul).ˇ with a weight of up to 1.7 kg (Jardas, 1996). In the south-

V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203 197

ern Adriatic, the wrasse inhabits rocky seabeds with many small pelagic ﬁsh, mollusks and sea urchins. When male

crevices, and it is always one individual. These habitats are interest for females increased, ﬁsh were removed to the

located on the outer side of islands facing the open sea laboratory tank (300 l). These specimens, one male (420 g,

and along vertical rocky sea beds (Onofri, 1975) at depths TL 34.0 cm, 4+ age) and one female (480 g, TL 33.0 cm, 4+

of 2–50 m (Jardas, 1996). The reasons for the reduction of age) spawned spontaneously. During the spawning period,

◦

green wrasse populations are due to intense commercial temperature was 14.2 C, salinity 38.1 psu, oxygen 7.2 mg/l,

and sport ﬁshing. and pH 7.9. After spawning, the ﬁsh were returned to the

The green wrasse is an obligatory carnivore, preying on aquarium pool. The same male also spawned with another

mollusks, worms, crabs and urchins (Quignard and Pras, female (458 g, TL 31.0 cm, 4+ age) ten days after the ﬁrst

1986; Onofri, 1975; Jardas, 1996). The species is a protog- spawning.

ynous hermaphrodite, and sex commences at a length of

27 cm (Quignard and Pras, 1986; Jardas, 1996). Spawning

2.2. Egg incubation and embryonic development

takes place at the end of winter and at the beginning of

spring in natural conditions (Onofri, 1975; Jardas, 1996).

The ﬁrst release of eggs occurred in the aquarium

Onofri (1975) states that this species attaches eggs to algae,

tank, and immediately afterwards, the male and the

but the author did not give any data on this phase of

female were transferred to the laboratory tank, where the

development for eggs transported to the laboratory. Onofri

spawning continued. We gathered the ﬁrst eggs released

(1970, 1975) presented the morphological and meristic

from the aquarium’s gravelly bottom, together with the

data of adult stages of green wrasse and other species of

gravel to which they were attached, which served as a

labrids in the southeastern Adriatic, but there is insufﬁcient

control for embryonic development in further research.

information on the early developmental stages of green

Prior to stocking in the experimental tank for incubation,

wrasse. Information on the spawning and early develop-

these egg samples were disinfected for 15 min using a

mental stages of another LABRID species Labrus merula on

low-concentration solution of formaldehyde (1 part 37%

the eastern shores of the Adriatic is given by Dulciˇ c´ et al.

formalin to 600 parts of water) (Ferguson, 1978; Cross and

(1999). Globally, much research has been carried out due

Needham, 1978). This egg sample was placed inside the lab-

to problems with parasites, such as sea lice. Due to dam- 2

oratory tank in a dish the size of the bottom 80 cm , with

ages in the rearing of salmonid caused by sea lice, in the

a permeable bottom made of plankton netting of 500 ␮m

last few years, the possibility of biological control by using

mesh for better aeration. Other eggs that were released

cleaner wrasse has become very interesting for aquacul-

during spawning in the laboratory tank were attached to

ture (Bjordal, 1990; Darwall et al., 1992; Kvenseth, 1993;

the tank bottom and could not be retrieved for sampling.

Treasurer, 1993, 1994, 1996, 2002; Deady et al., 1995;

The eggs had a constant daily exchange of 50–70% seawater

Young, 1996; Tully et al., 1996).

through a 50-␮m mesh net. The experiment was carried out

Due to the vulnerability and declining population num-

under an artiﬁcial photoperiod (12L:12D h, 2000 lux). The

bers of this species on the east coast of the southern

water was gently aerated from the bottom of the tank.

Adriatic, our investigations of controlled breeding are ◦

Eggs and larvae were incubated from 13.8 to 15.5 C

useful for repopulation or as potential mariculture in poly- ◦

(mean 14.4 C). Dead larvae were removed daily. After fer-

culture production for the ﬁsh market. This paper presents

tilization, a sample of 10–15 eggs was taken every 5–7 min

the ﬁrst data on egg, embryonic and larval development of

to determine the exact time of ﬁrst cleavage. Random sam-

wrasse under controlled laboratory conditions. The objec-

ples of 10–15 eggs were taken every hour during the ﬁrst

tives are to describe the early life history and to assist in

10 h after fertilization, and subsequently every 6 h. The egg

the identiﬁcation of the planktonic stages of this species,

diameter was measured and the stages of the embryonic

and also to provide ﬁrst information on possible breeding.

development were recorded using a binocular microscope.

Photos of individual stages were taken. The number of

2. Materials and methods

eggs and larvae were signiﬁcantly lower during the sec-

ond spawning with the same male and the other female.

2.1. Brood stock

Due to the low number of spawned eggs during the sec-

ond spawning, egg measurements and the monitoring of

Parental ﬁshes were collected from southeastern Adri-

embryonal development in this group was not carried out.

atic waters, around the island of Lokrum near Dubrovnik.

Fish were caught on hooks or in ﬁsh traps and, after being

quarantined, they were placed with other specimens in 2.3. Larval development

the brood stock tank. A parental stock (two males and six

females) was kept in aquaria at the Institute for Marine After hatching commenced, various measurements

and Coastal Research in Dubrovnik. The dimensions of the were made on live larvae, sampled randomly at least three

× ×

aquarium tank were 120 80 80 cm (0.8 m ). Sex was times a day, 8:00 am, 14:00 pm and 20:00 pm. All changes

determined based on body colors, size and behavior of indi- in the larvae were recorded. In each sample, 15–20 larvae

viduals during spawning. Fish were held under ambient were examined and measured.

salinity (37.1–39.2 psu, mean 38.5 psu), temperature (from Larvae were anaesthetized in a solution of ben-

◦

12.3 in February to 25.8 C in August), oxygen (7.2–8.2 mg/l, zocaine (0.05 mg/l) and carefully measured using an

mean 7.8 mg/l), pH (7.8–8.2, mean 7.9) and photoperiod ocular micrometer attached to a binocular microscope

conditions. During captivity, ﬁsh were usually fed with (±0.001 mm).

198 V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203

These measurements included: standard length (the

distance along the midline of the body, from the tip of the

snout to the end of the urostyle); total length (the distance

along the midline of the body, from the tip of the snout

to the end of caudal ﬁn rays) pre-anal length (the distance

along the midline the body, from the tip of the snout to the

anus); body depth (the perpendicular depth of the trunk at

the anus) head length (the distance between the tip of the

upper jaw and the cleithrum) eye diameter; longer diame-

ter length of yolk sac.

The time period until full yolk-sac absorption, as well as

the mouth opening, was also recorded. The mouth width

of larvae was measured with the larvae in dorsal position,

at the point where both lips meet (Shirota, 1970).

2.4. Larval feeding

Larvae were fed exclusively on the rotifers Brachionus

plicatilis, as a ﬁrst food after yolk-sac absorption and the

mouth opening. The rotifers were cultured in a thermo-

◦

static chamber at 26 C and at 25–28 psu. Rotifers fed on the

green alga, Chlorella sp. and were added to tanks with lar-

vae, to a density of 7–10 ind./ml. At the initiation of feeding,

60 rotifers were measured and a size range of 90–280 ␮m

was established. The number of larvae in the tank was mea-

sured daily in order to monitor the survival rate, taking

one litre of medium ﬁve times, in which the larvae were counted.

3. Results

3.1. Spawning

The start of spawning was observed in the aquarium

on March 26th at approximately 13:00 h. Before spawn-

ing, the dominant male chased away other ﬁsh from the

part of the aquarium tank chosen as a spawning place,

and changed into a dark-green color. A dominant male

would choose one of the mature females and spawning

occurred after a few days of courtship. The female also

changed color to a dark-green. Spawning continued after

ﬁsh were removed into the laboratory tank with an area

of 15 cm × 15 cm (≈225 cm ) and at 3–5 cm above the bot-

tom with tiny gravel. The male followed the female swiftly

(40–50 cm/s) in different directions above the spawning

place. As the female emitted eggs, the male started to fer-

tilize these eggs with short and fast body contractions on

the left and right side. These contractions continued for

2–3 s. Spawning in the laboratory tank was noted usually

Fig. 1. Cleavage and embryonic development of Labrus viridis: (A) ﬁrst

1–3 times, from the early morning hours to noon, over a cleavage (two cell stage) 2 h 11 min after spawning, (B) second cleavage

period of three days. The adhesive eggs were placed at the (four cell stage) 2 h 47 min after spawning, (C) fourth cleavage (sixteen

cell stage) 4 h 42 min after spawning, (D) morula stage 16 h 41 min after

bottom of the laboratory tank.

spawning, (E) blastula stage 26 h 35 min after spawning, (F) early gas-

trula stage 29 h 35 min after spawning (gastrula starts), (G) gastrula stage,

3.2. Embryonic development

33 h 50 min after spawning embryonic area well marked, (H) embryo, 42 h

33 min after spawning, optic vesicles well developed (d) embryo, 72 h

05 min after spawning the tip of the tail reaching posterior end of the

The developmental stages of the embryos are shown

head. Scale bar = 1 mm.

in Table 1 and Fig. 1. The average diameter of newly

spawned eggs was 1.01 0.03 mm, with the size varying

from 0.86 to 1.04 mm. Mature and fertilized eggs were

attached to the bottom of the tank by mucus. The yolk

was homogeneous and non-segmented. There were no

V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203 199

Table 1

◦

Embryonic development of Labrus viridis at a mean temperature 14.4 C.

Time Stage Description

h min

000 Fertilization

2 11 2 cells Meridional ﬁrst cleavage

2 47 4 cells Second cleavage

3 57 8 cells Cleavage parallel to the second

44216 cells Cleavage parallel to the ﬁrst

55032 cells

16 41 Morula The blastodisc consisted of many blastomeres

26 35 Blastula The blastodisc begones multilayered, visible

Blastocel

29 35 Gastrula Gastrulation starts

33 50 Gastrula Invagination of blastomeres ends

36 40 Nerula Formation of nerular groove starts

35 20

42 33 Embryo

50 37 12-h embryo stage Somatic segmentation begins, formation of

optic vesicles

52 16 Formation of miomeres begins

55 30 Miomeres formed

67 20 29-h embryo stage Movements of complete body were noted

72 05 Rhythmical movements every 15–17 s of 50%

embryos, melanophores appear on the head,

the tip of the tail reaching posterior end of the

head

78 30 48-h embryo stage Melanophores appear on the yolk sac and

faster rhythmical movements every 3–5 s

91 10 Melanophores appear on the tail

102 40 64-h embryo stage 30–32 melanophores on the yolk sac, 4

melanophores on the head

127 40 Free yolk sac larvae Hatching begins

130 10 All yolk sac larvae hatched

visible oil globules in the eggs, which we also did not 4.80 ± 0.22 mm and was characterized by an elongated yolk

record in the larvae. The ﬁrst and second cleavages are sac under the anterior part of the body and without an

shown in Fig. 1A and B. The eggs showed a typical discoidal oil drop. The body was segmented into 39–41 myomeres,

cleavage and the formation of equally sized blastomeres. 15–18 pre-anal and 22–25 post-anal myomeres. The mouth

In the gastrulation stage, the blastoderm showed expan- was undeveloped upon hatching, the eyes were not pig-

sion and spread towards the vegetal pole (Fig. 1F). The mented, and a simple tubular gut was observed. There

embryo form was detectable after 35 h (Fig. 1G), and after were black and yellow-green chromatophores covering the

42 h (Fig. 1H), it was completely visible. During embry- head and the trunk, except for the caudal region. The dis-

onic development, ﬁrst dendritic melanophores appeared tance from the snout to the posterior end of the pigmented

on the yolk sac (n = 22–32) and on the dorsal and ventral area was 4.12 ± 0.03 mm. After hatching, the head length

surface (n = 33–41) 55 h after fertilization. The number and was 12% of the total length. In newly hatched larvae, the

the position of melanophores were the same during the body depth ranged from 0.71 mm to 0.95 mm. The anus

entire embryonic stage. Heart beating was observed after opened slightly and was located more than halfway to

67 h, and 1–2 movements of the complete body were noted the caudal part of the body. The locations with a higher

during 1 min. The embryo was folded, with the tip of the tail number of melanophores were on the surface of the yolk

reaching the posterior end of the head 72 h after fertiliza- sac and around the anus. On the yolk sac, 60–64 dendritic

tion, and optic capsules were observed (Fig. 1I). Just before melanophores were noted, and 7–8 around the anus. There

hatching, movements were noted every 3–5 s. were no melanophores on the dorsal and ventral ﬁn-folds.

After hatching, the larvae were distributed in the upper lay-

ers of the tank. Only occasional tail contractions were noted

3.3. Hatching and larval development

on the ﬁrst day.

At the beginning of the second day after hatching,

Hatching started approximately 127 h after fertiliza-

granular pigmentation of the eyes was apparent and the

tion (31st March, around 20:00 h), and within 3 h, all

melanophores were bigger around the anus and in the dor-

yolk-sac larvae hatched. During hatching, the temperature

◦

sal region of the notochord. The development of a caudal

was 14.5 C, salinity 38.0 psu, oxygen 7.1 mg/l, and pH 7.8.

ﬁn started with changes in the tissue of the ventral region

Changes in larval length during the ﬁrst seven days of life

of the notochord. The changes were noticed as a thicken-

are shown in Table 2.

ing of tissue, the beginnings of formation of rays. One-third

The body of newly hatched larvae was elongated imme-

of the yolk sac had been adsorbed (Fig. 2B). The second

diately after the release of larvae from eggs (Fig. 2A).

day after hatching, larvae were dispersed throughout the

The average total length of newly hatched larvae was

200 V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203 C) ◦ (

Daily temperature 14.5 14.4 14.2 14.5 14.8 13.9 14.1 14.4

April).

20 20 20 20 20 20 20 20 Number measurements 6th

(mm)

March

0.01 0.02 0.01 0.03 0.01 0.03 0.03 0.02

± ± ± ± ± ± ± ±

eye 31st

0.40 0.35 0.36 0.37 0.38 0.39 0.39 0.41 The diameter from

20:00

(mm)

yolk-sac

day

0.09 0.01 0.10 0.12 0.13 0.14

± ± ± ± ± ±

every

Longest 1.28 1.01 0.81 0.66 0.37 0.09 Resorbed Resorbed diameter

measured

(mm)

0.08 0.08 0.09 0.10 0.12 0.14 0.15 0.14 were

depth ± ± ± ± ± ± ± ±

table

0.83 0.84 0.88 0.92 0.94 0.97 0.99 1.07 Body in

(values

0.05 0.05 0.04 0.06 0.06 0.07 0.08 0.08

Fig. 2. Early larval development of Labrus viridis: (A) newly hatched yolk-

length hatch ± ± ± ± ± ± ± ±

sac larvae (4.76 0.21 mm SL) 33 somites, (B) 24-h old yolk-sac larvae

(4.94 ± 0.15 mm SL), (C) 4-day old yolk-sac larvae (5.65 ± 0.28 mm SL) the post 0.80 0.58 0.61 0.66 0.87 1.01 1.18 1.22

Head

(mm) ±

mouth is invaginated but not open, (D) 7-day old larvae (6.81 0.29 mm

SL), (E) 20-day old larvae (7.11 ± 0.39 mm SL). days

ﬁrst

length 0.11 0.11 0.12 0.14 0.17 0.18 0.18 0.20

entire tank column. The larvae density in the tank was the ± ± ± ± ± ± ± ±

2.16 ind./l. 2.56 2.59 2.67 2.73 2.86 3.12 3.32 3.41

(mm)

Preanal

By day 3, the development and growth of melanophores during

continued. Changes on the head were noted, such as the

development of the mouth. The jaws, maxilla and mandible

larvae

formed without signiﬁcant difference. The body and noto- 0.21 0.19 0.15 0.29 0.27 0.28 0.26 0.29

(mm)

chord were straight. Half of the yolk sac had been adsorbed. ± ± ± ± ± ± ± ±

yolk-sac

At the beginning of the 4th day, 90% of the yolk sac was 4.76 4.83 4.94 5.11 5.33 5.65 5.79 6.81

Standard length

absorbed (Table 2), the foregut and hindgut were visible, viridis

and the anus was open. The eye was completely pigmented

and the mouth started opening. The number and size of Labrus

melanophores increased. The differentiation of pectoral 0.22 0.20 0.15 0.24 0.26 0.28 0.28 0.30 of

length

± ± ± ± ± ± ± ±

ﬁns had started (Fig. 2C).

During the 5th day, the mouth opened and was func- shape 4.80 5.17 5.67 5.97

Total

(mm)

tional with an opening of 0.33–0.51 mm. Melanophores and

were now present on the anal ﬁn-fold. The melanophores

(5–7) were located in a line on the ﬁn fold just under the length (mm)

notochord. The ﬁfth day after hatching, the number of lar- in after

vae was 1.66 ind./l. 2 0

+12+24 +48+72 +96 4.93 5.35 5.87 By day 6, the melanophores on the anal ﬁn-fold were +120 +144 6.04 hatching Hours

Table

Changes bigger and had spread on the entire ﬁn-fold around the

V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203 201

Table 3

Comparation of data for eggs, yolk-sac larvae and larvae of different labrid species.

Species Source Egg diameter Hatched Larvae-start Preanal The eye

(mm) yolk-sac larvae of length diameter (mm)

Ctenolabrus rupestris Ehrenbaum (1905–1909) 3.14

Heincke and Ehrenbaum (1900) 1.95–2.19

Holt (1899) 0.72–1.01

Labrus bergylta Matthews (1887) 1.00 3.80 2.10 0.27

Danois (1913) 0.70–0.80 ∼6.50

Symphodus cinereus Quignard (1962) 0.72–0.73 3.00 3.14

Crenilabrus ocellatus Sparta (1931) 0.68 3.00

Symphodus (Crenilabrus) melops Quignard (1967) 0.80–0.85 2.50–3.00 2.90–3.10

Ctenolabrus rupestris Stone (1996) 0.85 2.35

Symphodus melops Stone (1996) 0.90 2.60–2.80

Labrus merula Dulciˇ c´ et al. (1999) 0.83–1.05 3.76 4.45 2.00 0.29

Labrus viridis Present study 0.86–1.04 4.80 5.97 2.56 0.35

anus. In 80% of the larvae, the yolk sac had been completely The time of maturation and partial spawning corresponded

absorbed. An increase in pigmentation was also noted after to the behavior of other Labridae, L. merula, but the release

the absorption of the yolk-sac and at the beginning of active of ripe eggs in this species lasted for 20 days (Dulciˇ c´ et al.,

feeding. 1999).

During the 7th day, 4–5 melanophores appeared on The behavior of males during the spawning period was

the frontal part of the ﬁn-fold around the anus (Fig. 2D). similar to L. merula males. The way of courtship and the

The head length after the 7th day increased to 20.1% of movements during spawning above the chosen area on the

the total length. Larvae were mobile and started feeding sea bed were the same for these species. The only differ-

actively. The passage of food was clearly visible along the ence was in the color of the body during spawning, as L.

open digestive tract. The number of larvae in the tank was viridis only intensiﬁes its color, while L. merula completely

0.73 ind./l. changes the color of its body, which is particularly pro-

Three weeks after hatching, the total length ranged from nounced in the male (Dulciˇ c´ et al., 1999). For the female,

6.91 to 7.25 mm, and the pre-anal length ranged from 3.62 body colorations are less intense than with males and

to 3.97 mm. The head length was 21.3% of the total length. together with thicker abdomens, it represents a visual way

The period between the 7th and the 20th day after of determining sex.

hatching was characterized by a more intensive body pig- The eggs of L. viridis are demersal, glued down in

mentation of the larvae (Fig. 2E). Pigmentation occurred nests or shallow depressions (Onofri, 1970). Most labrids

in the same places as on the yolk-sac larvae. Some body spawn small (0.5–1.1 mm) pelagic eggs, but three northeast

parts were without pigmentation, such as the head, ven- Atlantic genera have adhesive, demersal eggs with parental

tral and caudal ﬁn-fold and caudal part of the notochord. A care (Richards and Leis, 1984). In the Mediterranean, only

small number of larvae survived up until the 20th day after two of the labrid species, Ctenolabrus rupestris and Coris

hatching (0.1 ind./l). julis, spawn pelagic eggs (Russell, 1976). In comparison

with L. merula and other labrids, L. viridis have larger eggs

3.4. Larval feeding and newly hatched yolk-sac larvae (Table 3). The main

characteristic of L. viridis eggs is the sticky mucous layer

The ﬁfth day after hatching, we recorded the beginning that glues eggs to the bottom. A few hours before hatching,

of active feeding with 35% of the larvae. The maximum gape the mucous layer loses its stickiness and separates from the

of the open mouth averaged 0.44 mm. After 24 h, 72% of eggs.

the larvae started to feed on rotifers. We noted that larvae Temperature has an important role in the duration

showed interest in prey only when it appeared in front of of embryonic and larval stages (Quignard, 1967; Lasker,

them at 2–3 mm and the ﬁrst day after being given rotifers, 1981). In the present study, embryonic development at

◦

the larvae hunted 4–5 times per hour. a mean temperature of 14.4 C lasted 127 h, which is

Larval survival up to the mouth opening (66 h after longer than the embryonic development of L. merula (106 h

◦

hatching) was 76.6%; 10 days after hatching, 15.2% larvae 45 min) with a mean temperature of 14.3 C. It may be con-

survived; after 20 days 4.6% larvae survived and 24 days cluded that L. viridis have longer embryonic development

after hatching, all larvae died. than L. merula at the same incubation temperatures.

In addition to egg sizes, newly hatched larvae, the dura-

tion of embryonic and larval stages, pigmentation in the

4. Discussion

early stages is one factor that can help in the identiﬁcation

of labrid species. Ford (1922) described larval pigment pat-

Spawning of green wrasse in the aquarium started in

terns of different labrids and grouped larvae according to

the second half of March, which is in accordance with

their pigmentation. According to this division, L. viridis lar-

Grubisiˇ c´ (1962, 1988), Onofri (1975), and Jardas (1996).

vae are similar to L. merula and Labrus bergylta. The main

Green wrasse is a serial spawner and spawning occurred

differences between these species are in the size (Table 3)

between a dominant male and one of the mature females.

202 V. Kozulˇ et al. / Animal Reproduction Science 125 (2011) 196–203

and development time of melanophores on the anal ﬁn-fold Darwall, W., Costello, M.J., Lysaght, S., 1992. Wrasse-how well do they

work? Aquacult. Ireland 501, 26–29.

and on top of the head. Melanophores on the anal ﬁn-fold of

Deady, S., Varian, S.J.A., Fives, J.M., 1995. The use of cleaner-ﬁsh to control

L. viridis were noted at the beginning of the 6th day, which

sea lice on two Irish salmon (Salmo salar) farms with particular refer-

is ﬁve days later than with L. merula, but melanophores on ence to wrasse behavior in salmon cages. Aquaculture 131, 73–90.

Dulciˇ c,´ J., Kozul,ˇ V., Kraljevic,´ M., Skaramuca, B., Glamuzina, B., Re, P., 1999.

top of the head were noted on the 7th day, which is nine

Embrionic and larval development of the brown wrasse Labrus merula

days earlier than with L. merula.

(Pisces: Labridae). J. Mar. Biol. Assoc. U. K. 79, 327–332.

The length of newly hatched green wrasse yolk-sac lar- Ehrenbaum, E., 1905–1909. Eier und Larven von Fischen. Nordisches

Plankton 1, 1–413.

vae is larger than the larvae of L. merula and L. bergylta,

Ferguson, H., 1978. Anaesthesia and treatment. In: Fish Diseases, Proceed-

whose larvae have 3.7–3.8 mm lengths (Matthews, 1887;

ings 106, Refresher Course for Veterinarians , Sydney, Australia, 23–27

Dulciˇ c´ et al., 1999). The growth speed of newly hatched lar- May, 1978, p. 30.

vae is higher in the ﬁrst 24 h (7.2%), and after the 7th day, Fernández-Díaz, C., Pascual, E., Yúfera, M., 1994. Feeding behaviour and

prey size selection of gilthead seabream, Sparus aurata L., larvae fed

larvae are 20.6% longer than at hatching. In comparison to

on inert and live food. Mar. Biol. 118, 323–328.

L. merula larvae (Dulciˇ c´ et al., 1999), the newly hatched lar-

Ford, E., 1922. On the postlarvae of the wrasses occurring near Plymouth.

vae of L. viridis grew faster in the ﬁrst hours, but after the J. Mar. Biol. Assoc. U. K. 12, 693–699.

Grubisiˇ c,´ F., 1962. Prilog poznavanju vremena mrijesˇcenja´ nekih jadran-

7th day, growth was similar.

skih riba, Biljeskeˇ – Notes Institute of Oceanography and Fisheries.

The spawning period and geographical distribution

Split 18, 1–4.

could also assist in distinguishing labrids species (Dulciˇ c´ Grubisiˇ c,´ F., 1988. Ribe, rakovi i skoljkeˇ Jadrana. Edit. ITRO Naprijed., 239

pp.

et al., 1999), but knowledge of embryonic and larval devel-

Heincke, F., Ehrenbaum, E., 1900. Eier und Larven von Fischen der

opment of each labrid species is the main determining

Deutschen Bucht, II Die Bestimmung der schwimmenden Fischeier

factor, especially in areas with many labrid species. und die Methodik der Eimessungen. Wissenschaftlide Meeresunter-

suchunger HelgolandNF 3, 127–332.

After the mouth opened, we noted the start of active

Holt, E.W.L., 1899. Recherches sur la reproduction des poissons osseux

feeding by larvae that accepted brachionus as ﬁrst food.

principalement dans le golfe de Marseille. Annales du Musée

Considering that the functional opening of the mouth is d’Historie Naturelle de Marseille 5, 1–128.

Jardas, I., 1996. Jadranska ihtiofauna. Zagreb. In: Skolskaˇ knjiga , p. p. 533.

based on the prey/gape ratio by only 25–50% (Shirota,

Kvenseth, P.G., 1993. In: Reinertsen, H., Dahle, L.A., Jorgensen, L., Tvin-

1970; Busch, 1996; Fernández-Díaz et al., 1994; Munk,

nereim, K. (Eds.), Use of wrasse to control salmon lice. Fish Farming

1997; Cunha and Planas, 1999; Ostergaard et al., 2005), Technology, Balkema Rotterdam, pp. 227–232.

the functional size of the mouth opening for wrasse larvae Lasker, R., 1981. Marine ﬁsh larvae: morphology, ecology and relation to

ﬁsheries. University of Washington Press, Washington, p. 131.

according to this ratio would be 0.11–0.22 mm. Based on

Matthews, J.D., 1887. Note on the ova, fry and nest of the ballan wrasse

the observed mouth opening, about 70% of added rotifers

(Labrus maculatus). In: Fifth Annual Report, Fisheries Board Scotland,

had a lorica width suitable as ﬁrst prey. pp. 245–247.

Munk, P., 1997. Prey size spectra and prey availability of larval and small

juvenile cod. J. Fish Biol. 51 (Suppl. A), 340–351.

5. Conclusion

Onofri, I., 1970. Prilog poznavanju ekologije porodice Labridae peljeskogˇ

kanala i okolnog podrucja.ˇ MSc Thesis, PMF Sarajevo, Bosnia and

Hercegovina.

This study suggests that it is possible to maintain brood

Onofri, I., 1975. Biosistematske karakteristike vrsta familije Labridae

stock and obtain mature individuals that spontaneously

(Pisces, Teleostei) jugoslavenskog dijela Jadrana. PhD thesis, PMF Sara-

spawn in controlled conditions. The results showed that jevo, Bosnia and Hercegovina, p. 290.

Ostergaard, P., Munk, P., Janekarn, V., 2005. Contrasting feeding patterns

after yolk sac resorption, the larvae were large enough to

among species of ﬁsh larvae from the tropical Andaman Sea. Mar. Biol.

be fed with rotifers. Existing technology in the mariculture

146, 595–606.

of commercial species can meet the requirements for the Quignard, J.P., 1962. La reproduction chez les Labridés, le nid, l’oeuf et la

larve de Symphodus cinereus. Naturalia Menspeliensia. Zoologie Mont-

rearing and preservation of this species. Future research,

pellier 4, 51–61.

alongside the protection and repopulation of this species,

Quingnard, J.P., 1966. Recherches sur les Labridae (poisons Téléostéens

can also be directed towards polyculture rearing in terms Perciformes des Côtes Européenes—systématique et biologie). Nat.

of market positioning. The use of wrasse as cleaner ﬁsh Monspel. Serie. Zool. 5, 7–248.

Quignard, J.P., 1967. L’oeuf et la larvae de Labridé Symphodus (Crenilabrus)

can perhaps also alleviate problems relating to ectopara-

melops (Linné, 1758). Inﬂuence de différents facteurs physico-

sites.

chimique sur la durée du development embryonnaire. Revue des

Travaux de l’Institut des Pêches Maritimes. Paris, 31, 355–358.

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