Comparison of four types of sampling gears for estimating age-0 yellow perch density

Figures & data

Table 1. Mean density (standard error) of age-0 yellow perch, operational effort, coefficient of variation of mean densities (CV), and the number of samples (n) required to detect a 25% change in mean age-0 yellow perch abundance for four different gears in Pickerel and Clear lakes, South Dakota, during August 2011.

Lake	Gear	Fish density (number/m^3)	CV	n	Operational effort (min)
Pickerel	Beach seine	3.04 (0.93)^a	53	40	23 (1.8)^b
	Benthic sled	0.07 (0.03)^b	79	95	12 (1.0)^b
	Push trawl	0.09 (0.06)^b	106	166	13 (2.1)^b
	Drop net	1.04 (0.63)^b	120	205	45 (9.3)^a
Clear	Beach seine	4.10 (0.71)^a	33	22	23 (2.1)^a,b
	Benthic sled	0.65 (0.39)^b	79	90	13 (1.5)^b
	Push trawl	1.64 (0.82)^b	86	106	17 (2.1)^a,b
	Drop net	0.07 (0.05)^b	134	305	28 (4.3)^a
Note: For each lake, means with the same letter(s) are not significantly different at α = 0.10.

Figure 1. Length-frequency histograms and mean total lengths for age-0 yellow perch collected during August 2011 in Pickerel Lake (left panel) and Clear Lake (right panel) with a beach seine, benthic sled, drop net, and push trawl. N = number of individuals; TL = total length (mm); SE = 1 standard error of the mean total length. For each lake, length frequencies of gears with the same letter did not differ significantly (Kolmogorov-Smirnov tests; p > 0.03).