Influence of monsoon-driven hydrographic features on thaliacean distribution in waters around Taiwan, western North Pacific Ocean

Zoological Studies

Table 1 Hydrographic variables (at 5-m depth) and average abundance, RA, and OR of the Thaliacea in 2004

Species	Winter			Summer
Species	Mean ± SE	RA	OR	Mean ± SE	RA	OR
	(individuals/1,000 m³)	(%)	(%)	(individuals/1,000 m³)	(%)	(%)
Thalia rhomboides	454 ± 160	43.77	61.76	1,026 ± 404	32.13	82.35
Doliolum denticulatum	313 ± 96	30.15	97.06	634 ± 235	19.84	97.06
Doliolum nationalis	0	0	0	728 ± 547	22.81	14.71
Thalia orientalis	77 ± 29	7.43	61.76	207 ± 40**	6.49	76.47
Pyrosoma verticillatum	4 ± 4	0.35	2.94	232 ± 161	7.25	17.65
Thalia democratica	37 ± 11	3.53	50.00	134 ± 37*	4.21	79.41
Thalia cicar	50 ± 16	4.80	61.76	50 ± 12	1.57	64.71
Weelia cylindrica	4 ± 4	0.40	2.94	67 ± 29*	2.09	38.24
Salpa fusiformis	48 ± 25	4.65	44.12	12 ± 8	0.39	23.53
Iasis zonaria	14 ± 9	1.38	20.59	0	0	0
Salpa younti	0	0	0	13 ± 5*	0.40	26.47
Cyclosalpa sewelli	0	0	0	10 ± 4*	0.31	17.65
Dolioletta gegenbauri	3 ± 2	0.30	5.88	1 ± 1	0.04	2.94
Brooksia rostrata	2 ± 2	0.17	5.88	1 ± 1	0.03	2.94
Traustedtia multitenticulata	2 ± 2	0.16	5.88	1 ± 1	0.02	2.94
Doliolina mulleri	1 ± 1	0.08	5.88	1 ± 1	0.04	2.94
Pegea confoederata	0	0	0	1 ± 1	0.02	2.94
Cyclosalpa affinis	0	0	0	0.1 ± 0.1	0.004	2.94
Unidentified old nurse	29 ± 6	2.79	61.76	74 ± 14**	2.33	85.29
Unidentified Thaliacea	1 ± 0.4	0.05	5.88	1 ± 1	0.03	11.76
Total thaliaceans	1,037 ± 224	100	-	3,193 ± 705**	100	-
Species number	4.3 ± 0.4			5.7 ± 0.4*
Species diversity	0.9 ± 0.1			1.0 ± 0.1
Temperature (°C)	22.74 ± 0.45			28.96 ± 0.17***
Salinity	34.24 ± 0.09			34.14 ± 0.04
Chlorophyll a (μg/L)	0.12 ± 0.04			0.06 ± 0.02

RA, relative abundance; OR, occurrence rate. Asterisks indicate a significant difference between seasons according to an ANOVA at *p < 0.05, **p < 0.01, and ***p < 0.001.