1. Black Sea[1], in spite of its poor

1.     INTRODUCTION

 

The Black Sea is the utmost
seperated ecosystem amidst all inland seas of the nature, whose merely thin
connection to other seas is with the Mediterranean owing to the narrow Turkish
straits system. A comparatively various marine fauna appears in the Black Sea1,
in spite of its poor salinity (17‰) and anoxic waters under depths of 180 m
(with high levels of H2S). Approximetly 3,800 species were identified in the Black Sea. 42.9%
of them belong to fungi, algae and higher plants, 52.5% belong to
invertebrates, 4.5% belong to fishes and 0.1% belong to marine mammals2.

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Fish is one of the tops
aquatic organisms that be able to avail in serve out the protein 3,4.
The fishery industry acts a major role in Turkey’s public economy as a main
welding of job and external exchange earnings. Turkey has many marine fishery
resources which the commercially important resources include many demersal and
small pelagic fish species. Fish production decreased from 589,129 tonnes in
2007 to 301,463.6 tonnes in 2016 5. One of the problems associated
with the fishing industry is the over-fishing of commercial fish species along
the year. The Black Sea, being the most important fishing ports, is being
developed by the government of Turkey as a fishing centre. The Black Sea is
heavily influenced by a kinds of contaminants6,7,8,9. Household
and industrial wastes are inducing large damage to the fishing industry in
Turkey. Sinop city is one of the veriest important fishing cities in the Black
Sea coasts10. Recreational fishing is also common in Sinop in addition to commercial fisheries. Indeed
Sinop coasts are encircled by sea has done fisheries a prominent means of
revenue10. The catch from marine fisheries is supplied to the
local fish markets as freshly. The per capita consumption is only 6.2 kg p.a.
in 2015 5. This value is higher in Turkey’s coastal cities
including Sinop. Sinop is the centre of the fishing industry with many trawlers
and fishing vessels using Sinop Fish Harbour.

 

Recent review has pointed
out that numerous contaminants which several of them having carcinogenic
attributes, toxic materials such as heavy metals have been occured in the
marine ecosytem6. These hazardous pollutants are also moving into
the diet of the human beings whose consumed seafood including fish. However, many
recent studies11,12,13,14,15,16 indicate that heavy metals in
commercial fish species caught by the Sinop coast are well below the acceptable
levels set for EU Commission Regulations 17,18,19,20 and TFC 21.
In this respect, Sinop fish are consumed and preferred species.

 

Although fishes constitute
solely a minor ratio of the biodiversity of the Black Sea, the main fish species such as anchovy, bluefish and Atlantic bonito and
historically and currently significant because of their great profitable worth.
The current study was performed throughout
the fishing seasons of 2013-2014, and several fundamental features of the fish
population in Inceburun coast of Sinop province of the Black Sea were examined.

 

2.     MATERIALS AND METHODS

 

Fish surveys were practised along the Inceburun coasts of
Sinop province in the Black Sea. Samples were captured at depths between 20-39
m at 5 different locations using bottom trawling hauls by a fishery vessel
during the fishing seasons of 2013-2014
(Figure 1).

 

 

Figure 1. The bottom trawl locations. This area is allowed for trawl.

 

The sizes of the bottom
trawl used were as follows: head rope length – 10 m; mesh size – 44mm. Haulings
were applied on daylight with haul duration of 30 min – 45 min at trawl speed
3.66 km/h on the ground (Table 1). After each hauling, total catch was sorted
and cased by species. Next to casing process biometric measurements of each
specie was made.

 

 

Table 1. Information of Trawl Operations

Haul #

Coordinate

Time

Total
Duration

Average
Depth

Velocity

Start

Finish

Start

Finish

Haul 01

42° 7’48.47″N
34°57’42.84″E

42° 7’23.67″N
34°56’36.23″E

09:45

10:15

30 min.

39 m

2 knots

Haul 02

42°10’44.32″N
34°53’46.37″E

42°10’9.83″N
34°54’42.27″E

11:10

11:40

30 min.

20 m

2 knots

Haul 03

42° 9’41.56″N
34°57’44.13″E

42° 9’4.59″N
34°58’36.74″E

12:35

13:05

30 min.

29 m

2 knots

Haul 04

42° 6’15.19″N
35° 2’39.06″E

42° 6’48.04″N
35° 1’42.31″E

14:35

15:20

45 min.

34 m

2 knots

Haul 05

42° 7’56.96″N
35° 2’38.75″E

42° 7’16.19″N
35° 3’21.51″E

16:10

16:55

45 min.

35 m

2 knots

 

 

2.1.Length – Weight Relationship

Equation (1) was used to determine length – weight relationship:

(1)      
W=a Lb

where;

W        : Weight (g)

L         : Total length (cm)

a & b   : regression coefficients

 

·        
Fulton’s Condition
Factor (K)

 

K= (W/L3) * 100

 

2.2. Biomass
Estimation

The swept area method was used for estimation of biomass. The swept area,
a, can be estimated from equation (2)

(2)           a  = D*hr*X2

D       = V*t

where:

?          : Swept area

V         : Velocity of the trawl over the ground

X2       : Fraction of the head – rope length

hr         : Head rope length

t           : Duration of haul

D         : Distance covered

Equation (3) was used for the estimation relative biomass, the catch per
unit of area (CPUA)

(3)   Cw/a

Where;

a          :
Swept area

Cw     : Catch

 

Seized species were weighed
and measured then fixed in 4% formalin for laboratory analysis, except for
large sized fish. Species were identified using keys in Whitehead et al.
22, Fischer et al. 23 and Bat et al.
24 . All fish species captured were identified to the smallest
taxon. Literature was surveyed information on the status of threatened fishes.

 

Individual
communications were done with domestic fishermen, so that get knowledge on
regional fishery activities and current issues in the region. Fishermen were also inquired into information on the
condition of commercially utilize fish stocks and threatened fishes. Available
papers was examined, particularly for species formerly presented from Sinop
coasts of the Black Sea, and each additional species records were included into the inventory of local
ichthyofauna.

 

3.     RESULTS

In the survey; 16
teleost species from 15 family, 2 elasmobranch species from 2 family and 2
species from invertebrates were sampled (Table 2). Fulton’s Condition Factor
has been calculated and illustrated in Table 3. Catch per unit area (CPUA) values of sampled fish of trawl operations in
Sinop-Inceburun region were shown in Table 4. Minimum, maximum and average length and
weight values of each species were showed in Table 5. As tunicates, crabs and
seahorses were released back to sea immediately after hauling, only the numbers
of those was recorded (Table 6).

 

Table 2. Fish of Sinop coasts during the bottom trawl survey in 2013-2014.

Class

Ordo

Familia

Genus

Species

Common
name

Chondrichtyes

Myliobatiformes

Dasyatidae

Dasyatis

Dasyatis
pastinaca

Common stingray

Rajiformes

Rajidae

Raja

Raja
clavata

Thornback ray

Osteichtyes

Perciformes

Mullidae

Mullus

Mullus
barbatus ponticus

Red Mullet

Pomatomidae

Pomatomus

Pomatomus
saltatrix

Bluefish

Carangidae

Trachurus

Trachurus
mediterraneus

Horse mackarel

Centracanthidae

Spicara

Spicara
maena

Blotched picarel

Trachinidae

Trachinus

Trachinus
draco

Greater weever

Gobiidae

Neogobius

Neogobius
melanostomus

Round goby

Mesogobius

Mesogobius
batrachocephalus

Toad goby

Uranoscopidae

Uranoscopus

Uranoscopus
scaber

Atlantic stargazer

Sciaenidae

Umbrina

Umbrina
cirrosa

Shi drum

Pleuronectiformes

Scophthalmidae

Psetta

Psetta
maxima

Turbot

Bothidae

Arnoglossus

Arnoglossus
laterna

Mediterranean scaldfish

Soleidae

Pegusa

Pegusa
lascaris

Sand sole

Gadiformes

Lotidae

Gaidropsarus

Gaidropsarus
mediterraneus

Shore rocking

Clupeiformes

Clupeidae

Alosa

Alosa
fallax nilotica

Twaite shad

Scorpaeniformes

Scorpaenidae

Scorpaena

Scorpaena
porcus

Black scorpionfish

Syngnathiformes

Syngnathidae

Hippocampus

Hippocampus
hippocampus

Sea horse

 

Table 3. Calculated Fulton’s
Condition Factor of sampled fish species in the region (insufficient data were
excluded)

Species

K

N

Mullus barbatus

1.15 ± 0.14

188

Pomatomus saltatrix

0.91 ± 0.01

100

Trachurus
mediterraneus

0.86 ± 0.02

56

Uranoscopus scaber

1.61 ± 0.03

29

Raja clavata

1.64 ± 0.01

28

Scorpaena porcus

1.93 ± 0.08

22

Trachinus draco

0.20 ± 0.07

8

Gobius
melanostomuss

1.27 ± 0.05

20

Gobius
batrachocephalus

0.84 ± 0.04

4

 

 

 

Main target species of bottom-trawl are whiting and red mullet in the
region. Whiting could not have been caught during surveys. Beside, app. 90% of
total catch was consisted of bycatch. 63% of red mullet was under the legal
catch size which is 13 cm. Furthermore, red mullet was the most abundant
species in terms of individual numbers.

 

Table 4. CPUA
Values of Sampled Fish by Stations

 

CPUA (kg/km²)

Species

I.
Station

II.
Station

III.
Station

IV.
Station

V.
Station

Average

Mullus barbatus
(Red mullet )

69.02

55.30

24.54

2.33

33.92

37.02±11.68

Pomatomus saltatrix
(Bluefish)

70.93

2.62

0

23.13

110.05

41.35±21.37

Trachurus mediterraneus
(Horse mackarel)

18.25

5.41

2.35

7.98

1.09

7.02±3.05

Uranoscopus scaber
(Atlantic stargazer)

17.54

12.46

20.38

5.94

13.37

13.94±2.46

Dasyatis pastinaca
(Common stingray)

8.96

470.93

50.00

59.89

182.26

154.41±84.25

Scorpaena porcus
(Black scorpionfish)

0

0

0

25.17

0

5.03

Neogobius
melanostomus
(Round Goby )

36.12

0.00

0.00

12.20

6.19

10.90

Trachinus
draco
(Greater weever )

0.00

7.27

1.91

0

1.46

2.13

Mesogobius
batrachocephalus
(Toad Goby)

17.87

0

0

0

0

3.58

Psetta maxima
(Turbot)

0

2.62

12.57

3.39

0

3.71

Umbrina cirrosa
(Shi drum)

0

44.64

17.49

0

0

12.43

Spicara maena
(Blotched picarel )

0

0

0

0.40

1.09

0.30

Raja clavata
(Thornback ray)

493.83

0

0

128.93

39.78

132.51

Pegusa lascaris
(Sand Sole )

0

1.75

0

0

0

0.35

Arnoglossus laterna (Mediterranean
scaldfish)

0

0

0

0.55

0

0.11

Gaidropsarus
mediterraneus
(Shore rockling)

2.62

0

0

0

0

0.52

Total

735.14

603.01

129.23

269.91

389.22

425.30±109.69

 

 

 

Table 5. Average length values of sampled fish

Species

N

Min.
 Length (cm)

Average
Length (cm)

Max.
  Length (cm)

Min.
Weight (gr)

Average
Weight (gr)

Max.
 Weight (gr)

Mullus
barbatus (Red
mullet )

188

3.8

12.07±0.18

18.5

2

19.78±0.84

64

Pomatomus
saltatrix (Bluefish)

100

12

17.43±0.21

22.9

12

50.02±1.81

110

Trachurus
mediterraneus
(Horse
mackarel)

56

8

11.18±0.26

18

3

12.95±1.07

58

Uranoscopus
scaber
(Atlantic
stargazer)

29

9.5

14.1±0.46

20.4

12

50.07±5.72

150

Dasyatis
pastinaca
(Common stingray)

28

20

31.64±1.11

46

121.83

583.76±67.02

1699.58

Scorpaena
porcus
(Black scorpionfish)

22

8.5

11.67±0.40

17

15

31.41±2.64

62

Neogobius melanostomus
(Round Goby )

20

11.4

15.96±0.57

22.8

20

58.3±7.03

170

Trachinus draco (Greater weever )

8

11

15.86±0.41

18

15

26±1.23

35

Mesogobius batrachocephalus
(Toad Goby)

4

20.5

21.3±0.13

22.2

70

81.75±2.93

105

Psetta
maxima  (Turbot)

3

15

19.3±0.84

24

48

70.5±5.91

93

Umbrina
cirrosa (Shi drum)

2

20

31±2.89

42

200

508.5±81.02

817

Spicara
maena
(Blotched picarel
)

2

9.5

12.25±0.72

15

11

20.5±2.49

30

Raja
clavata (Thornback ray)

3

40

58.67±3.53

78

63.79

4555.94±757.54

9036.68

Pegusa
lascaris (Sand sole )

1

16.5

32

Arnoglossus
laterna
(Mediterranean scaldfish)

1

12.5

15

Gaidropsarus mediterraneus
(Shore rockling)

1

19

48

Table 6. Numbers of Tunicates, Sea horses and Crabs by Stations.

Species

I. Station

II. Station

III. Station

IV. Station

V. Station

Total

Ascidia
aspersa (Tunicate)

320

18

  –

 –

 –

338

Hippocampus
hippocampus
(Seahorse)

11

2

1

 –

 –

14

Liocarcinus
depurator
(Crab)

63

124

80

250

95

612

 

Length – Weight
relationships of sampled fish which are in sufficient sample size were
illustrated in Figure 2. Red mullet, horse mackarel and black scorpionfish
showed negative allometric growth while blufish showed isometric growth. Average
length values of red mullet which is the target species of demersal trawl were
as follows; 12.01 cm, 12.06 cm, 10.75 cm, 10.15 cm, 13.89 cm  respective to station number. Average length
of red mullet specimens caught in V. Station were significantly higher than
those of derived from another stations according to executed One-Way Anova
statistical test (p3 refers to allometric growth.  

 

Data respecting to the
marine fishes of Sinop coast is restricted. Information on local fish faunas is
scarce. A total of 94 species belonging to 44 families in the Sinop – Samsun
coastline have been identified 31. Gönener and Bilgin32
reported that whiting (Gadus merlangus
euxinus), red mullet (Mullus barbatus ponticus), turbot (Psetta
maxima maeotica), black scorpion fish (Scorpaena porcus), shad (Alosa
sp.), picarel (Spicara maena), horse mackerel (Trachurus
mediterraneus), picked dogfish (Squalis achantias), thornback ray (Raja
clavata) and goby (Gobius sp.) were sampled with bottom-trawl in the
Sinop-Inceburun region between February-April 2007 and January-April 2008
fishing seasons. Similarly Gönener and Özdemir33 studied annual,
monthly and daily catch amounts from Sinop-Inceburun region between
September-December 2008 and January-April 2009 fishing periods. They found
whiting (Gadus merlangus euxinus), red mullet (Mullus barbatus
ponticus), turbot (Psetta maxima maeotica), shad (Alosa sp.),
picarel (Spicara maena), horse mackerel (Trachurus mediterraneus),
shark (Squalis achantias) and goby (Gobius sp.) in the same
region of the Black Sea. Sampled species are similar with current study except
for whiting. It can be considered that since the haulings were performed in
shallow waters, whiting could not have been caught in our surveys.

 

A sum of 3455 authorized
fishermen and 536 fishing boats are existing in Sinop bearing its regions with
ports such as Ayanc?k and Gerze34. Fishing activities sustain
round the year bound up with meteorological conditions outside of closed season
and the period of the catch season sets amongst 60 and 270 days. The quantity
of catch demontrates variation. The basins where seaside fishing operations happen are Akliman,
Sar?kum, Inceburun and Gerze (Çak?ro?lu) 34.

 

Consequently of
eutrophication caused by rised nutrient entrance over large north-western
rivers pending the last few decades, the Black Sea ecosystem has been related
to intense alters in recent years. Ultmost changes owing to changed nutrient
level were reflected in the qualitative and quantitative composition of biota
with the inclusion of ichthyofauna31. The Black Sea has a fairly narrow continental shelf and
very thin oxygenated upper layer and eutrophic structure which provides habitat
for pelagic fishes. This is rised in the catch composition of the landings, in
which small pelagic fish more than 90% of the total catch35. Bottom
trawls are productive fishing equipments for demersal fisheries and it is the
very significant fishing technique in the catch of those fish species with a
proportion of 60%36. The top economic worth of marine yields from
the Black sea include anchovy, sprat, horse mackerel, bonito, bluefish of pelagic
species and red mullet, whiting, turbot of demersal fishes and sea snails and
mussels, respectively37. The catching of fish in Sinop area was
mainly formed by similar species. Besides, the Black Sea specially in Sinop
shores was the best spawning field for whole trading fish species, inclusive
the predator species, which migrated for spawning or feeding 31. Turkish
fishery output is set up marine fishery which produced 76% of the production
for 200738. According to TUIK 5 anchovy creates 67%
of the Black Sea fisheries and 49% of Turkish fisheries. Thus, whicever vary in
the distribution of anchovy and the amount of fishing in any fishing season has
a serious influence on overall yearly fishing quantity37. The
Turkish Government operative two main matters seeing decrease the cost of
fishery by 1) Tax Relief Scheme for Diesel Oil Used in Fishing Vessel and 2)
Subsidized Credit Scheme for Fishermen 35. Gücü 35 further
exuded that reducing the cost of fishing relieved fisheries economy to a
certain extent, on the other hand the impact of these decisions on fish stocks
have been detrimental. Usually, Turkish fisheries with the inclusion of Sinop
fishery indicate coastal fishing activities which are on a diurnal basis by
leaving the regional port, fishing in depth the day and going back to the port39.
Moreover, it is rather apparent that the Black Sea area including Sinop shores
have a substantial impact of aggregate production of marine fish of Turkish
fisheries and Sinop fisheries constitute a prominent fishery industry and help
for employment. There is a progress in the validity of catch and biological
data for economic species get caught off the Sinop coast of the Black Sea. It
may having said that biological and ecological information catch and effort
statistics for all economical species are yet lacking. Accordingly, it is
eminently committed that forth researches are required prior to any outcome is
drawn.