Marbled crayfish Procambarus virginalis invades a nature reserve: how to stop further introductions?

Figures & data

Figure 1. Sampling locations where Procambarus virginalis was detected by local citizens prior to our survey (red squares) in Ostrów Lubelski. Highlighted water bodies represent lakes and ponds (light blue areas), rivers (dark blue lines), and amelioration ditches (light blue lines).

Table I. Sampling sites examined for crayfish presence.

	No.	Type/Name	Coordinates		Crayfish presence
Ostrów Lubelski	1	Miejskie Lake	N 51.5077	E 22.8847	Detected
	2	Dry ditch	N 51.5084	E 22.8857	Detected
	3	Wet ditch	N 51.5099	E 22.8848	Detected
	4	Dry ditch	N 51.5107	E 22.8855
	5	Wet ditch	N 51.5120	E 22.8809
	6	Kleszczów Lake	N 51.5213	E 22.8932	Detected
	7	Wet ditch	N 51.5235	E 22.8970
Warsaw	-	Morskie Oko	N 52.2063	E 21.0253	Detected

Figure 2. Locations in Ostrów Lubelski where live specimens of Procambarus virginalis were detected: Miejskie Lake – 1 (a), Kleszczów Lake – 6 (b), wet ditch – 3 (c), dry ditch – 2 (d).

Figure 3. Maximum Likelihood phylogenetic tree including sequences obtained from collected Procambarus virginalis and GenBank stocked sequences.

Figure 4. Indications of Procambarus virginalis in the terrestrial and littoral zone: intact dead specimens found on forest roads (a); dead crayfish in freshly dried ditch (b); crayfish burrows: in compacted forest soil (c), in moist sand soil (d), in moist clay (e), in leaves litter (f); used crayfish migration channels connecting puddles in wet the ditch (g, h).

Table II. The number of crayfish individuals inhabiting burrows in wet and dry ditches.

	Wet ditch burrows		Dry ditch burrows		Total
Crayfish inhabitants	n	%	n	%	n	%
0			21	43.8	21	34.4
1	7	53.8	16	33.3	23	37.7
2	2	15.4	2	4.2	4	6.6
3			3	6.3	3	4.9
5	2	15.4	1	2.1	3	4.9
7	1	7.7	2	4.2	3	4.9
10	1	7.7			1	1.6
11			1	2.1	1	1.6
14			1	2.1	1	1.6
17			1	2.1	1	1.6
Total	13	100.0	48	100.0	61	100.0

Table III. Size classes and number of collected Procambarus virginalis individuals (n), their proportion (%), average total lenght (AVG) in mm ± SD.

	Location
	Miejskie Lake		Kleszczów Lake		Wet ditch		Dry ditch		Total
Total length (mm)	N	%	n	%	n	%	n	%	n	%
<60					9	1.5	1	1.1	10	1.4
60–64					21	3.5			21	2.9
65–69					44	7.2	1	1.1	45	6.3
70–74			1	7.1	97	16.0	9	9.7	107	15.0
75–79					144	23.7	19	20.4	163	22.8
80–84			4	28.6	158	26.0	23	24.7	185	25.9
85–89			2	14.3	85	14.0	24	25.8	111	15.5
90–94			5	35.7	35	5.8	14	15.1	54	7.6
95–99	1	100.0	2	14.3	9	1.5	2	2.2	14	2.0
≥100					5	0.8			5	0.7
Total	1	100.0	14	100.0	607	100.0	93	100.0	715	100.0
AVG ± SD			87.2^aB±6.6		78.0^AB±8.4		81.9^Aa±7.3		78.7 ± 8.4

Values statistically significant—same letters (A,B—p < 0.01, a—p < 0.05).

Table IV. The presence of pereiopods, moulting and egg-carrying individuals.

	Location
	Miejskie Lake		Kleszczów Lake		Wet ditch		Dry ditch
	n = 1		n = 14		n = 607		n = 93
Description	n	%	n	%	n	%	n	%
Claws
none					7	1.2
one missing					48	7.9	7	7.5
both present	1	100	14	100	552	90.9	86	92.5
Other walking legs counts
5					3	0.5
6					5	0.8	1	1.1
7					12	2.0
8	1	100	14	100	587	96.7	92	98.9
Moulting individuals					95	15.7	1	1.1
Females with eggs					2	0.3	2	2.2