Pipefish are a member of the Syngnathidae family and an important component of the fish fauna, due to their tolerance to high temperature and salinity (Kornienko 2001; Hablützel, Wilson 2011) in estuarine areas and shallow coastal waters (Howard, Koehn 1985). Pipefish belong to the same family as seahorses and are widely used in many parts of the world, mainly in aquariums, ornamental items, and as a raw material in the traditional Chinese medicine in the Far East (Payne et al. 1998). Therefore, the species is threatened by excessive hunting and deterioration of their habitats.
Morphometric characteristics are important details revealing the structure and properties of fish stocks (Turan 2004). The degree of morphological diversity at the species or population level is evaluated by referring to morpho-ecological results of studies relating to the genetic structure (Chan 2001; Cakič et al. 2002). Length-weight and length-length relationships are frequently used in ichthyological studies to analyze fish stocks (Ricker 1975). These parameters enable local and regional comparisons of populations and species.
Over the last decade, studies focusing on morphometric characteristics of pipefish have gathered momentum (Cakič et al. 2002; Mwale 2005; Gurkan 2008; Gurkan, Taşkavak 2012; Yildiz et al. 2015; Khrystenko et al. 2015). However, no studies have been found in relation to different coastal areas of Turkey, except for those carried out in the Aegean and Black Sea regions. The objective of this study was to determine the morphometric characteristics of the
Lake Bafa is a natural barrier lake situated in the southeast region of the Büyük Menderes River delta, with an indented coastline. The sampling was carried out by seining in the coastal area of the Kapikiri region (37°30′N, 27°31′E-37°29′N, 27°31′E) of the lake at depths not exceeding 1–1.5 m (Fig. 1).
Study area (□: Kapikiri region in Lake Bafa)Figure 1
Pipefish samples were seasonally collected from the study area between November 2014 and March 2016 by seining in the coastal area at depths up to 1.5 m. Regulations of the ethical committee were followed during the capturing and processing of the fish species. The captured fish samples were transported to the laboratory in sealed vessels containing 70% ethanol. In the laboratory, total lengths of fish specimens (TL, mm) were measured using a measuring board, weights (W, g) were determined using a scale with 0.01 g sensitivity, and morphometric measurements were performed using a digital caliper with 0.001 mm sensitivity. Sexes of the pipefish specimens were macroscopically determined and the sex ratio of the captured species was calculated for the sampling area.
The total length-weight relationship of the samples was determined according to the procedure proposed by Ricker (1975). The length-weight relationship for the total body weight was calculated using the equation W = aLb, where W is the weight (g), L is the length (TL, mm),
The significance of the regression was assessed by ANOVA, and the
A total of 69 adult
A total of 77
Length-weight relationship in Figure 2
Length-weight relationship in Figure 3
The relationships (linear regressions) were significant for both species (
In total, 69 adult
Morphometric features of
Morphometric features
Range (mm)
M±SD
Range (mm)
M±SD
Total Length
55–130
86.7 ± 7.80
54–125
92.7 ± 18.09
Head Length
6.4–16.3
10.19 ± 3.30
6.5–13.5
2.76 ± 2.25
Head Depth
1.4–5.4
2.70 ± 10.09
1.2–4.5
2.44 ± 14.60
Body Depth
1.0–6.6
2.48 ±1.31
0.7–5.1
2.04 ± 10.78
Body Width
1.6–4.5
2.86 ± 11.58
1.1–5.1
2.73 ± 12.51
Mouth Width
0.43–2.5
1.12± 18.28
0.3–2.4
0.94 ± 0.36
Mouth Height
1.1–2.6
2.20 ± 2.36
0.8–3.3
1.42 ± 21.9
The regression analysis for
Length-length relationship values for specimens of
Variables
R2
Formulas
CI (95%)
F
Ln TL/HL
0.500
Y = –4.535 + 2.790x
–6.328; –2.741
38.015
Ln TL/BD
0.568
Y = 1.706 + 0.236x
1.228; 2.184
52.179
Ln TL/BW
0.55
Y = 1.499 + 0.221x
1.052; –1.945
46.140
Ln TL/HD
0.597
Y = –2.529 + 1.510x
–3.327; 1.103
56.275
Ln HL/MW
0.169
Y = 0.132 + 0.47x
0.36; –0.228
7.721
Ln HL/MH
0.522
Y = –0.37 + 0.41x
0.188; 0.354
43.509
Ln TL/HL
0.778
Y = –1.109 + 0.189x
0.901; 1.289
131.028
Ln TL/BD
0.809
Y = –4.210 + 0.376x
1.970; 2.743
152.915
Ln TL/BW
0.367
Y = –1.040 + 0.325x
–1.698; –0.382
20.888
Ln TL/HD
0.745
Y = –1.718 + 0.215x
–2.155; 0.897
105.071
Ln HL/MW
0.642
Y = 0.986 + 0.564x
0.961; 0.422
64.571
Ln HL/MH
0.219
Y = 1.006 + 0.020x
0.965; 1.046
10.095
In the case of
Tables 3 and 4 show the comparison of the morphometric characteristics between the sexes. According to the t-test results, the difference between the body width of the sexes was statistically significant for both
Morphometric features of sexes,
Morphometric features
Males
Females
N
Range
M ± SD (mm)
N
Range
M ± SD (mm)
Total Length
25
74–117
93.94 ± 14.79
44
72–130
97.58 ± 18.45
Head Length
25
8.76–15.08
11.38 ± 1.80
40
11.95–6.73
11.94 ± 2.87
Head Depth
25
2.35–4.24
3.08 ± 0.55
40
2.11–5.38
3.28 ± 0.900
Body Depth
24
1.26–4.62
2.74 ± 0.99
40
1.33–6.64
3.41 ± 1.75
Body Width
24
1.56–4.47
2.67 ± 0.59
40
1.88–3.86
2.88 ± 0.56
Mouth Width
25
0.90–1.66
1.30 ± 0.25
40
0.63–2.52
1.45 ± 0.54
Mouth Height
23
1.35–2.74
1.87 ± 0.36
40
1.12–3.24
1.90 ± 0.65
Morphometric features of sexes,
Morphometric features
Males
Females
N
Range
M ± SD (mm)
N
Range
M ± SD (mm)
Total Length
31
82–117
98.16 ± 12.32
76
73–125
99.35 ± 14.87
Head Length
31
9.88–13.91
11.88 ± 1.53
52
7.05–15.33
11.97 ± 2.43
Head Depth
31
2.56–3.83
3.16 ± 0.43
52
2.25–4.50
3.24 ± 0.64
Body Depth
31
1.27–4.10
2.77 ± 0.87
52
1.510–5.06
2.98 ± 1.11
Body Width
31
1.58–3.58
2.71 ± 0.59
52
2.16–4.51
3.30 ± 0.76
Mouth Width
31
0.72–2.36
1.28 ± 0.45
52
0.85–1.97
1.39 ± 0.34
Mouth Height
31
1.19–2.32
1.68 ± 0.34
52
1.27–3.34
2.01 ± 0.53
In this study, selected morphometric characteristics of
Since the early 2000s, a growing number of studies have shown that the length and weight values of the pipefish species vary depending on the region of their distribution (Table 5). The results of this study were compared with the results obtained in the studies carried out in the last decade (Gurkan, Taskavak 2007; Gurkan, Çulha 2008; Veiga et al. 2009; Gurkan et al. 2010; Keskin, Gaygusuz 2010; Altin et al. 2015; Yildiz et al.2015; Khrystenko et al. 2015; Taylan et al. 2018). The minimum length values of
Selected studies and their results on the two species from Turkey and other parts of the world
Species
Locality
N
Range
a
b
r
Reference
TL (cm)
W (g)
Strymon estuary
12
7.8–13.2
0.0003
3.156
0.962
Koutrakis & Tsikliras 2003
Porto-Lagos lagoon
5
8.3–12.4
0.0001
3.729
0.958
Spain
1260
1.3–10.9
0.00068
2.922
0.970
Verdiell-Cubedo et al. 2006
Iberian Peninsula
64
3.9–12.1
0–0.7
0.0004
3.1201
0.926
Morey et al. 2003
Moray firth
4
0.00006
3.527
Coull et al. 1989
Spain
225
11–29.3
0.00072
2.8831
0.958
Valle et al. 2003
İzmir Bay
570
3.3–25.6
0.01–12.29
0.0001
3.43
0.91
Gurkan & Taşkavak 2007
İzmir Bay
310
0.0001
3.43
0.89
Gurkan 2004
İzmir Bay
202
6.1–20.7
0.07–4.49
0.0001
3.63
0.97
Özaydin & Taşkavak 2006
Arade estuary, southern Portugal
57
2.9–10.5
0.00015
3,53
0.963
Veiga et al. 2009
Arade estuary, southern Portugal
66
7.1–34.6
0.00020
3.33
0.989
Candarli Bay (north Aegean Sea)
9
2.78–10.60
0.08–0.78
0.0015
2.859
0.739
Gurkan et al. 2010
Candarli Bay (north Aegean Sea)
77
5.40–21.20
0.06–4.98
0.0003
3.256
0.912
Erdek Bay (Sea of Marmara, Turkey)
298
4.5–15.1
0.0002
3.181
0.901
Keskin & Gaygusuz 2010
Erdek Bay (Sea of Marmara, Turkey)
15
10.3–37.8
0.0004
3.069
0.964
River Strymon (Northern Greece)Estuary
137
3.6–13.5
0.0002
3.42
0.982
Petriki et al. 2011
Eastern Ionian Sea
419
2.2–22.1
0.00031
3.22
0.95
Liousia et al. 2012
Eastern Ionian Sea
390
2.6–24.8
0.00032
3.30
0.97
Gökçeada Island
10
11.3–17
0.49–1.72
0.000
3.359
0.907
Altın et al. 2015
Gökçeada Island
12
11.4–25.5
0.04–6.75
0.000
3.592
0.956
Western Black Sea
280
15.6–39.2
0.0001
3.415
0.898
Yildiz et al. 2015
South Africa
133
4.6–21.6
0.00038
3.074
0.961
Harrison 2001
Croatia
22
7.6–13.9
0.0004
3.122
0.958
Dulčić & Glamuzina 2006
Kremenchug Reservoir,
60
0.69–1.32
0.18–1.20
0.0004
3.131
0.865
Khrystenko et al. 2015
60
0.69–1.31
0.15–1.53
0.0003
3.241
0.778
Dneprodzerzhinsk Reservoir
60
0.86–1.41
0.23–1.41
0.0003
3.167
0.919
Turkey
17
21.3–28.4
4.51–11.92
0.0003
3.115
0.926
Bok et al. 2011
Black Sea
4
25.7–33.9
2.19–13.97
Kasapoğlu & Düzgüneş 2014
Tunisian waters
104
7–19.8
0.19–3.32
3.4 × 10–6
2.62
0.85
Ben Amor et al. 2011
Tunisian waters
267
7.1–20.7
0.13–3.83
3.07 × 10–6
2.64
0.86
Iberian coast
579
3.7–11
0.02–1.0
0.00025
3.36
0.956
Vieria et al. 2014
Iberian coast
529
3.6–41.4
0.02–54.57
0.00020
3.34
0.980
The species
The difference in the body depth is the most distinct morphometric difference between
In
Among the morphometric characteristics of
In both species, the differences between the sexes in terms of the body width are statistically significant (
In conclusion, the two pipefish species occurring in Lake Bafa,