Population structure and reproductive biology of <i>Loricariichthys melanocheilus</i> Reis &amp; Pereira, 2000 (Siluriformes: Loricariidae) in the rio Ibicuí, Brazil

Zardo, Éverton Luís; Behr, Everton Rodolfo

doi:10.1590/1982-0224-20140052

Éverton Luís Zardo

Universidade Federal do Rio Grande do Sul (UFRGS), Faculdade de Agronomia, Avenida Bento Gonçalves, 7712, 91540-000 Porto Alegre, RS, Brazil. everton_zardo@hotmail.com

Everton Rodolfo Behr

Universidade Federal de Santa Maria (UFSM), Centro de Ciências Rurais, Avenida Roraima, 1000, Camobi, 97105-900 Santa Maria, RS, Brazil. everton_behr@hotmail.com

Figures (14)
Tables (3)

Thumbnail

Fig. 1.
Map with location of sampling points. P1 = Point 1; P2 = Point 2; P3 = Point 3.

Thumbnail

Fig. 2.
Distribution by length classes for separate sexes and grouped sexes of Loricariichthys melanocheilus in the rio Ibicuí, Rio Grande do Sul.

Thumbnail

Fig. 3.
Distribution of Loricariichthys melanocheilus in the rio Ibicuí by length classes for separate sexes in point 1. a: Lagoon and b: River.

Thumbnail

Fig. 4.
Distribution of Loricariichthys melanocheilus in the rio Ibicuí by length classes for separate sexes in point 2. a: Lagoon and b: River.

Thumbnail

Fig. 5.
Distribution of Loricariichthys melanocheilus in the rio Ibicuí by length classes for separate sexes in point 3. a: Lagoon and b: River.

Thumbnail

Fig. 6.
Overlapping lines for linear regression, length-weight relationship and their respective equations between separate sexes of Loricariichthys melanocheilus in the rio Ibicuí, Rio Grande do Sul.

Thumbnail

Fig. 7.
Bimonthly variations in the total (K) and somatic (K´) condition factors for Loricariichthys melanocheilus males in the rio Ibicuí, Rio Grande do Sul. (DJ = December/January, FM = February/March, AM = April/May; JJ = June/July, AS = August/September, ON = October/November).

Thumbnail

Fig. 8.
Bimonthly variations in the total (K) and somatic (K´) condition factors for Loricariichthys melanocheilus females in the rio Ibicuí, Rio Grande do Sul. (DJ = December/January, FM = February/March, AM = April/May; JJ = June/July, AS = August/September, ON = October/November).

Thumbnail

Fig. 9.
Bimonthly variations in the gonadosomatic index (GSI) and hepatosomatic index (HSI) for Loricariichthys melanocheilus males in the rio Ibicuí, Rio Grande do Sul. DJ = December/January, FM = February/March, AM = April/May; JJ = June/July, AS = August/September, ON = October/November.

Thumbnail

Fig. 10.
Bimonthly variations in the gonadosomatic index (GSI ) and hepatosomatic index (HSI ) for Loricariichthys melanocheilus females in the rio Ibicuí, Rio Grande do Sul. DJ = December/January, FM = February/March, AM = April/May; JJ = June/July, AS = August/September, ON = October/November.

Thumbnail

Fig. 11.
Bimonthly distribution of gonad maturity stages of Loricariichthys melanocheilus males in the rio Ibicuí, Rio Grande do Sul. DJ = December/January, FM = February/ March, AM = April/May; JJ = June/July, AS = August/ September, ON = October/November); A = immature, B = developing, C = mature D = spent.

Thumbnail

Fig. 12.
Bimonthly distribution of gonad maturity stages of Loricariichthys melanocheilus females in the rio Ibicuí, Rio Grande do Sul. DJ = December/January, FM = February/ March, AM = April/May; JJ = June/July, AS = August/ September, ON = October/November); A = immature, B = developing, C = mature D = spent.

Thumbnail

Fig. 13.
Distribution of gonad maturity stages of Loricariichthys melanocheilus males in the rio Ibicuí by point of collection. 1L, 2L and 3L = Lagoon of points 1, 2 and 3 respectively, 1R, 2R and 3R = River of points 1, 2 and 3 respectively.

Thumbnail

Fig. 14.
Distribution of gonad maturity stages of Loricariichthys melanocheilus females in the rio Ibicuí by point of collection. 1L, 2L and 3L = Lagoon of points 1, 2 and 3 respectively, 1R, 2R and 3R = River of points 1, 2 and 3 respectively.

Thumbnail

Table 1.
Total and bimonthly sex ratio of Loricariichthys melanocheilus in the rio Ibicuí, Rio Grande do Sul.

Thumbnail

Table 2.
Distribution by sampling points and their respective sex ratios for Loricariichthys melanocheilus in the rio Ibicuí, Rio Grande do Sul. (1R, 2R and 3R = Points 1, 2 and 3 in the river; 1L, 2L and 3L = Points 1, 2 and 3 in lagoons).

Thumbnail

Table 3.
Gonadosomatic Index (GSI), Total Condition Factor (K), Somatic Condition Factor (K'), Gonad Condition Factor (ΔK) and his standards deviation of Loricariichthys melanocheilus in rio Ibicuí by points of collection. (1R, 2R and 3R = Points 1, 2 and 3 in the river; 1L, 2L and 3L = Points 1, 2 and 3 in lagoons). *Different letters in rows indicates significance (p < 0.05).

Months	Females	Males	Total	X²	Ratio F:M
Dec-Jan	70	53	123	2.34 (p > 06)	1:1
Feb-Mar	37	57	94	4.25 (p < 06)	1:1.54
Apr-May	7	10	17	0.52 (p > 06)	1:1
Jun-Jul	12	9	21	0.42 (p > 06)	1:1
Aug-Sep	19	20	39	0.02 (p > 06)	1:1
Oct-Nov	85	15	100	49.0 (p < 06)	5.6:1
Total	230	164	394	10.39 (p < 06)	1.38:1

Points	Females	Males	Total	X²	Ratio F:M
1R	3	3	6	0 (p > 06)	1:1
2R	53	29	82	7.02 (p < 06)	1.82:1
3R	23	13	36	2.77 (p > 06)	1:1
1L	92	57	149	8.22 (p < 06)	1.61:1
2L	40	48	88	0.72 (p > 06)	1:1
3L	19	14	33	0.75 (p > 06)	1:1
Total	230	164	394

Males
	Point 1L	Point 1R	Point 2L	Point 2R	Point 3L	Point 3R
GSI	0.17 ±0,03	-	0.08 ±0.009	0.29 ±0.19	0.03 ±0.009	0.04 ±0.01
K	31.76 ±0.42	-	31.56 ±0.33	30.57 ±0.43	29.71 ±0.7	32.00 ±0.75
K’	31.71 ±0.42	-	31.53 ±0.33	30.48 ±0.44	29.70 ±0.69	31.99 ±0.74
ΔK	0.05 ±0.01	-	0.03 ±0.003	0.09 ±0.06	0.01 ±0.003	0.01 ±0.006
Females
	Point 1L	Point 1R	Point 2L	Point 2R	Point 3L	Point 3R
GSI	2.80 ±0.27	-	1.94 ±0.31	3.34 ±0.31	0.68 ±0.25	2.83 ±1.13
K	19.78^a ±0.21	-	18.19^b ±0.19	18.42^b±0.28	17.96^b ±0.40	18.66^ab ±0.36
K’	18.84 ±0.18	-	17.83 ±0.19	17.81 ±0.28	17.83 ±0.38	18.15 ±0.42
ΔK	0.60^c ±0.05	-	0.35^ac ±0.05	0.61^ac ±0.05	0.13^b ±0.05	0.51^abc ±0.2

Brasil

Brasil

Population structure and reproductive biology of Loricariichthys melanocheilus Reis & Pereira, 2000 (Siluriformes: Loricariidae) in the rio Ibicuí, Brazil