Laboratory Evaluation of the Survival of Fish Impinged on Modified Traveling Water Screens

Figures & data

FIGURE 1. Schematic diagram of the test flume, including the isolation screen, traveling water screen, collection trough, and collection net.

TABLE 1. Summary of pertinent P-values from the maximum likelihood estimates for the mortality regression models for all species tested. Asterisks denote significant differences at P < 0.05; down arrows indicate that mortality decreased significantly with increasing fish length and plus signs that treatment fish exhibited significantly greater mortality than control fish.

Species	Model	Length	Velocity	0.3 m/s	0.6 m/s	0.9 m/s
Bigmouth Buffalo	0.823
Bluegill	<0.001*	<0.001* ↓	0.0005*	0.8860	0.0004* +	0.0601 +
Channel Catfish	0.634
Freshwater Drum	0.190
Fathead Minnow	0.215
Golden Shiner	<0.001*	<0.001* ↓	0.724
Palmetto bass	0.992
Largemouth Bass	0.055	0.077		0.117
White Sucker	<0.001*	<0.001* ↓	0.742
Yellow Perch	0.039*	0.005* ↓	0.314

TABLE 2. Summary of pertinent P-values from the maximum likelihood estimates for the injury regression models for all species tested. See Table 1 for additional details.

Species^a	Model	Length	Velocity	0.3 m/s	0.6 m/s	0.9 m/s
Bigmouth Buffalo	0.023*	0.004* ↓	0.268
Bluegill	<0.001*	<0.001* ↓	0.139
Bluegill excluding CA	0.001*	0.007* ↓	0.008*	0.003* +	0.394	0.659
Channel Catfish	0.020*	0.070	0.030*	0.010* +	0.971	0.766
Freshwater Drum	<0.001*	<0.001* ↓	0.996
Fathead Minnow	0.011*	0.192	0.015*	0.009* +	0.304	0.582
Fathead Minnow excluding CA	0.004*	0.096	0.009*	0.003* +	0.329	0.810
Golden Shiner	0.577
Palmetto bass	0.993
Largemouth Bass	<0.001*	0.224	<0.001*	0.276	0.001* +	0.047* +
White Sucker	<0.001*	<0.001* ↓	0.595
Yellow Perch	0.166

^aCA = conspecific aggression.

TABLE 3. Summary of pertinent P-values from the maximum likelihood estimates for the scale loss regression models for all species tested. See Table 1 for additional details.

Species	Model	Length	Velocity	0.3 m/s	0.6 m/s	0.9 m/s
Bigmouth Buffalo	<0.001*	<0.001* ↓	<0.001*	0.278	<0.001* +	<0.001* +
Bluegill	<0.001*	<0.001* ↓	<0.001*	0.134	<0.001* +	<0.001* +
Freshwater Drum	<0.001*	<0.001* ↓	0.001*	0.732	0.001* +	0.002* +
Fathead Minnow	0.003*	0.783	0.001*	<0.001* +	0.545	0.629
Golden Shiner	<0.001*	<0.001* ↓	<0.001*	<0.001* +	<0.001* +	<0.001* +
Palmetto bass	0.376
Largemouth Bass	0.313
White Sucker	<0.001*	<0.001* ↓	<0.001*	0.487	<0.001* +	<0.001* +
Yellow Perch	0.075

TABLE 4. Percentages of fish collected by species, collection time, and velocity treatment. At the end of the 2-h test, free-swimming fish upstream of the traveling water screen were moved toward the screen with a mechanical crowder; these fish were held and evaluated separately and designated as “crowded” in this table.

		0.3 m/s		0.6 m/s		0.9 m/s
Species	Collection time	n	%	n	%	n	%	Control n
Bigmouth Buffalo	15 min	3	1.2	33	35.1	132	93.0
	1 h	3	1.2	3	3.2	5	3.5
	2 h		0.0		0.0	3	2.1
	Crowded	239	97.6	58	61.7	2	1.4
	Control							295
Bluegill	15 min	66	19.4	225	68.6	317	100.0
	1 h	11	3.2	17	5.2		0.0
	2 h	17	5.0	10	3.0		0.0
	Crowded	246	72.4	76	23.2		0.0
	Control							397
Channel Catfish	15 min	48	23.3	71	48.0	174	70.7
	1 h	58	28.2	26	17.6	40	16.3
	2 h	33	16.0	13	8.8	17	6.9
	Crowded	67	32.5	38	25.7	15	6.1
	Control							490
Freshwater Drum	15 min	15	6.2	46	20.0	203	99.5
	1 h	6	2.5	9	3.9		0.0
	2 h	9	3.7	10	4.3		0.0
	Crowded	213	87.7	165	71.7	1	0.5
	Control							512
Fathead Minnow	15 min	164	41.7	307	89.5	295	99.7
	1 h	25	6.4	16	4.7		0.0
	2 h	36	9.2	9	2.6	1	0.3
	Crowded	168	42.7	11	3.2		0.0
	Control							493
Golden Shiner	15 min	80	21.9	350	93.6	385	99.0
	1 h		0.0		0.0	4	1.0
	2 h	3	0.8		0.0		0.0
	Crowded	282	77.3	24	6.4		0.0
	Control							485
Palmetto bass	15 min	13	5.3	16	6.6	270	75.8
	1 h	5	2.1	19	7.9	45	12.6
	2 h	13	5.3	26	10.8	21	5.9
	Crowded	212	87.2	180	74.7	20	5.6
	Control							498
Largemouth Bass	15 min	4	1.0	215	59.9	344	95.3
	1 h	1	0.3	5	1.4	4	1.1
	2 h	9	2.3	11	3.1	1	0.3
	Crowded	380	96.4	128	35.7	12	3.3
	Control							501
White Sucker	15 min	196	52.5	273	80.5	362	96.8
	1 h	25	6.7	22	6.5	9	2.4
	2 h	17	4.6	7	2.1	3	0.8
	Crowded	135	36.2	37	10.9		0.0
	Control							459
Yellow Perch	15 min	18	15.0	118	75.6	159	98.1
	1 h	10	8.3	10	6.4	3	1.9
	2 h	5	4.2	7	4.5		0.0
	Crowded	87	72.5	21	13.5		0.0
	Control							498

TABLE 5. Mean ± SE FL, total number of fish tested (n), percent dead 48 h after testing, and 95% confidence intervals (CIs), by species and velocity. Confidence intervals were calculated using the normal approximation of a binomial distribution. Freshwater Drum, lacking forked tails, were measured to total length.

		0.3 m/s			0.6 m/s			0.9 m/s			Control
	FL		% Dead			% Dead			% Dead			% Dead
Species	(mm)	n	at 48 h	95% CI	n	at 48 h	95% CI	n	at 48 h	95% CI	n	at 48 h	95% CI
Bigmouth Buffalo	72.1 ± 0.26	245	0.0	0.0–0.2	94	0.0	0.0–0.5	142	0.0	0.0–0.4	295	0.3	0.0–1.1
Bluegill	47.6 ± 0.19	340	0.9	0.0–2.1	328	4.6	2.2–7.0	317	2.2	0.4–4.0	397	1.5	0.2–2.8
Channel Catfish	64.2 ± 0.17	206	1.0	0.0–2.6	148	0.0	0.0–0.3	246	0.4	0.0–1.4	490	0.0	0.0–0.1
Freshwater Drum	84.7 ± 0.22	243	0.0	0.0–0.2	230	0.0	0.0–0.2	204	0.5	0.0–1.7	512	0.2	0.0–0.7
Fathead Minnow	54.5 ± 0.16	393	2.3	0.7–3.9	343	3.2	1.2–5.2	296	1.7	0.1–3.3	493	1.2	0.1–2.3
Golden Shiner	74.3 ± 0.31	365	1.6	0.2–3.0	374	1.3	0.0–2.6	389	1.5	0.2–2.8	485	1.2	0.1–2.3
Palmetto bass	60.6 ± 0.14	243	0.4	0.0–1.4	241	0.0	0.0–0.2	356	0.3	0.0–1.0	498	0.0	0.0–0.1
Largemouth Bass	98.5 ± 0.30	394	1.0	0.0–2.1	359	2.2	0.5–3.9	361	2.8	1.0–4.6	501	0.8	0.0–1.7
White Sucker	79.8 ± 0.35	373	4.3	2.1–6.5	339	4.7	2.3–7.1	374	4.5	2.3–6.7	458	3.1	1.4–4.8
Yellow Perch	49.7 ± 0.27	120	0.8	0.0–2.8	156	2.6	0.0–5.4	162	1.2	0.0–3.2	498	1.0	0.0–2.0

TABLE 6. Percent injury by species and velocity.

Species	Velocity (m/s)	Percent injured
Bigmouth Buffalo	0.3	1.6
	0.6	1.1
	0.9	3.5
	Control	1.4
Bluegill	0.3	6.8
	0.6	7.3
	0.9	4.4
	Control	4.8
Channel Catfish	0.3	3.4
	0.6	0.0
	0.9	0.4
	Control	0.6
Freshwater Drum	0.3	0.0
	0.6	0.9
	0.9	0.0
	Control	1.0
Fathead Minnow	0.3	23.4
	0.6	18.1
	0.9	13.9
	Control	15.0
Golden Shiner	0.3	2.7
	0.6	4.6
	0.9	2.6
	Control	3.7
Palmetto bass	0.3	0.0
	0.6	0.0
	0.9	0.3
	Control	0.0
Largemouth Bass	0.3	0.8
	0.6	6.1
	0.9	3.9
	Control	1.6
White Sucker	0.3	28.7
	0.6	25.4
	0.9	22.5
	Control	20.0
Yellow Perch	0.3	1.7
	0.6	1.9
	0.9	0.0
	Control	1.0

TABLE 7. Percent scale loss category by velocity and species.

		Velocity
Species	Scale loss (%)	0.3 m/s	0.6 m/s	0.9 m/s	Control
Bigmouth	<3	42.0	16.0	29.6	48.5
Buffalo	3–20	45.3	58.5	21.1	38.0
	20–40	9.4	18.1	15.5	10.2
	>40	3.3	7.5	33.8	3.4
Bluegill	<3	88.8	84.8	82.3	91.7
	3–20	8.5	7.9	7.6	2.5
	20–40	1.5	2.7	6.9	2.8
	>40	1.2	4.6	3.2	3.0
Freshwater	<3	99.6	95.7	96.1	99.4
Drum	3–20	0.4	3.9	3.9	0.4
	20–40	0.0	0.0	0.0	0.0
	>40	0.0	0.4	0.0	0.2
Fathead	<3	76.6	84.8	85.1	86.4
Minnow	3–20	19.3	12.2	11.5	10.1
	20–40	3.8	2.0	3.4	1.6
	>40	0.3	0.9	0.0	1.8
Golden	<3	24.7	23.0	15.9	48.3
Shiner	3–20	40.0	38.5	31.1	40.4
	20–40	27.1	23.3	28.0	9.5
	>40	8.2	15.2	24.9	1.9
Palmetto	<3	97.9	99.2	96.9	98.2
Bass	3–20	2.1	0.8	2.8	1.6
	20–40	0.0	0.0	0.3	0.2
	>40	0.0	0.0	0.0	0.0
Largemouth	<3	99.0	99.2	97.5	98.6
Bass	3–20	0.5	0.8	1.1	1.2
	20–40	0.5	0.0	0.8	0.2
	>40	0.0	0.0	0.6	0.0
White	<3	72.9	59.3	48.9	81.3
Sucker	3–20	17.2	20.7	25.4	13.3
	20–40	7.5	15.0	20.1	3.5
	>40	2.4	5.0	5.6	2.0
Yellow	<3	100.0	98.1	98.2	99.8
Perch	3–20	0.0	0.0	0.6	0.2
	20–40	0.0	1.9	1.2	0.0
	>40	0.0	0.0	0.0	0.0

FIGURE 2. Distribution of injury types for the 886 fish with injuries.