Reference no: EM1384321

Table1. Mark-recapture Largemouth bass data from the Des Plaines River.

Size (cm)	Number of individuals day 1	Number of individuals day 2	Population density estimate
		Unmarked	Marked
< 10	73	64	22	570
10-20	35	28	13
20-30	20	22	18
> 30	6	4	2
Total	134	118	55

Using these data, estimate the density (number/hectare) of each size class plus the overall density. [Note: 1 hectare = 10,000 m².]

Sample calculation
For < 10 cm size class,
N = [73 x (64 + 22)] / 22
N = 285
The sample was taken from a 1,000 m x 5 m stretch of river which equals 5,000 m².
One hectare is 10,000 m², so we need to double our density estimate.             285 x 2 = 570 fish in the < 10 cm size class.

Bluntnose minnow

Complete the following table

Table 2. Mark-recapture Bluntnose minnow data from the Des Plaines River.

Size (cm)	Number of individuals day 1	Number of individuals day 2	Population density estimate
		Unmarked	Marked
< 3	252	174	63
3-6	196	145	54
6-9	177	132	58
> 9	34	26	11
Total	659	477	186

1. Which species was more numerous is the Des Plaines River?  How much more abundant?
2. Based on the data, which species grows to a larger size?
3. Which species do you think is the prey and which is the predator? Why?