TEIXEIRA, A. 1* COSTA, A. 2 BERNARDO, J.M.2 BRUXELAS, S . 3

MOVEMENT AND INTERACTION OF TWO EXOTIC CRAYFISH (Pacifastacus leniusculus AND Procambarus clarkii) USING PIT TELEMETRY IN EXPERIMENTAL CONDITIONS

1 CIMO- Centro de Investigação de Montanha, ESA, Instituto Politécnico de Bragança, 5301-855 Bragança, *amilt@ipb.pt

2 Departamento de Paisagem, Ambiente e Ordenamento, Universidade de Évora, Rua Romão Ramalho 59, 7000-671 Évora

3 Autoridade Florestal Nacional, Av. João Crisóstomo 26-28, 1069-040 Lisboa

River MaçãsDownstream

Bubb, D.H., M.C. Lucas, T.J. Thom & P. Rycroft 2002. The potential use of PIT telemetry for identifying and trackingcrayfish in their natural environment. Hydrobiologia 483: 225-230.

Caceci, T., S.A. Smith, T.E. Toth, R.B. Duncan & S.C. Walker 1999. Identification of individual prawns with implantedmicrochip transponders. Aquaculture 180: 41-51.

Clarke, K.R. & R.N. Gorley 2006. PRIMER v6: User manual/Tutorial. PRIMER-e Ltd, Plymouth.Greenberg, L.A. & P.S. Giller 2000. The potential of flat-bed passive integrated transponder antennae for studying

habitat use by stream fishes. Ecology of Freshwater Fish 9: 74-80.Perret, N. & J. Pierre. 2002. Impacts of tattooing and PIT-tagging on survival and fecundity in the alpine newt

(Triturusalpestris). Herpetologica 58: 131-138.Prentice, E.F., T.A. Flagg & C.S. McCutcheon 1990. Feasibility of using implantable passive integrated transponder (PIT)

tags in salmonids. American Fisheries Society Symposium 7: 317-322.Schooley, R.L., B. Van-Horne & K.P. Burnham 1993. Passive integrated transponders for marking free-ranging

Townsend’s ground squirrels. J. Mammal 74: 480-484.

River MaçãsHeadstream

Figure 3: Mean number of repeated and non-repeated data for the four classes defined-

Procambarus clarkii and Pacifastaculus leniusculus, male and female , detected for each

antenna (1 to 8) in the experimental pond, during July 2007.

Literature Cited

Tabela 2: Valores máximos e mínimos dos parâmetros microbiológicos obtidos da água obtidos durante 2006 e 2007 no Rio

Fervença: F1 (Fontes Barrosas, F2 (Campus ESA), F3 (Polis Jardim), F4 (jusante ETAR) e F5 (Ponte de Alfaião).

Pontos de Amostragem

Parâmetros F1 F2 F3 F4 F5

Coliformes fecais

UFC/100ml

0 7-13 5-8 6-9 5-8

Coliformes totais

UFC/100ml

1200-1800 3000-5000 2500-5000 7000-9500 6000-7600

Enterococos fecais

UFC/100ml

Ausentes Ausentes Ausentes Ausentes Ausentes

Conclusions

Methods

2

34

5

6

7

8

1

Perturbações ambientais na área urbana: impacto resultante de fenómenos

de origem antrópica (ex. contaminação orgânica e mineral, regularização);

Aumento expressivo do teor em sais dissolvidos e nutrientes (azoto e

fósforo) contribuiu para a elevada produção primária na Zona Polis;

Parâmetros microbiológicos não superaram os valores admissíveis (INAG,

2005) para os cursos de água superficiais (qualidade para usos múltiplos);

Degradação da galeria ripícola e alteração da morfologia do canal

modificaram substancialmente o funcionamento energético do ecossistema;

Variação na riqueza taxonómica e abundância relativa da comunidade de

macroinvertebrados ao longo do eixo longitudinal do curso de água;

Diminuição da integridade ecológica, explícita nos índices relacionados com

o biota (IBMWP), diversidade (H’), galeria ripícola (QBR) e canal (GQC);

Results

0

50

100

150

200

250

300

350

400

1 2 3 4 5 6 7 8

nº

rep

eate

d d

ata

(mea

n)

Antenna

P. clarkii female P. clarkii male P.leniusculus female P.leniusculus male

0

5

10

15

20

25

30

35

40

1 2 3 4 5 6 7 8

nº

no

n-r

epea

ted

dat

a (m

ean

)

Antenna

P. clarkii female P. clarkii male P.leniusculus female P.leniusculus male

Repeated data

Non-Repeated data

Figure 4: n-MDS ordination of repeated and non-repeated data for the defined classes,

considering 2007 and 2008. Simbol letters:1st and 2nd- species crayfish PC Procambarus clarkii /

PL Pacifastacus leniusculus; 3rd sex- male/female; Simbol numbers: 1st- crayfish individual

identification; 2nd- year 2007 and 2008

Figure 1: Schematic design and photos of the experiment in the artificial pond- eight

(black) panel antennae and the food source point (red star).

Figure 2: Marking procedures with the external implantation of PIT-Tags in the cephalotorax of crayfish.

Non-repeated data/Hour

Dayperiod

P. leniusculusfemale

P. leniusculusmale

P. clarkiimale

P. clarkiifemale

night 8.0 (2.46) 9.0 (3.74) 5.8 (4.20) 6.9 (1.91)

dawn 7.1 (1.22) 4.6 (0.44) 4.7 (0.46) 4.1 (1.98)

day 3.5 (1.07) 3.1 (0.53) 1.8 (0.60) 1.8 (0.28)

dusk 6.0 (0.95) 10.9 (8.03) 5.1 (3.31) 2.2 (0.84)

Table 1: Mean values and (Standard deviation) of non-repeated data for the four classes

defined- P. clarkii and P. leniusculus, male and female, considering four day periods:

night, dawn, day and dusk. July 2007.

non repeatedTransform: Square rootResemblance: S17 Bray Curtis similarity

speciesP.clarkii

P.leniusculus

PCF17

PCF27

PCF37

PCF47PCF57

PCM17

PCM27

PCM37

PCM47

PCM57

PLF17

PLF27

PLF37

PLF47

PLF57

PLM17

PLM27PLM37PLM47

PLM57

PCF18PCF28

PCF38

PCM18

PCM28

PCM38

PLF18

PLF28

PLF38

PLM18

PLM28PLM38

2D Stress: 0,08

repeated dataTransform: Square rootResemblance: S17 Bray Curtis similarity

speciesP.clarkii

P.leniusculus

PCF17

PCF27

PCF37

PCF47

PCF57 PCM17

PCM27

PCM37PCM47

PCM57

PLF17

PLF27

PLF37PLF47

PLF57PLM17

PLM27

PLM37

PLM47

PLM57PCF18

PCF28

PCF38

PCM18 PCM28PCM38

PLF18PLF28

PLF38PLM18

PLM28

PLM38

2D Stress: 0,16

Coexistence of two exotic crayfish species

In Northeast Portugal, the coexistence of Procambarus clarkii and Pacifastacus leniusculus was observed in a stretch of Rio Maçãs (Douro basin).

The red swamp crayfish, Procambarus clarkii, a sub-tropical species, was detected for the first time in 1979 (Rio Caia, Alentejo) and from there rapidly spread for all over the country.

This species is extremely resistant to severe climatic conditions, living in such contrasting environments as South or Northeast streams of Portugal.

The signal crayfish Pacifastacus leniusculus, a cold-water crayfish recently reached Portuguese waters (1997, NW Portugal) and is now spreading in Rio Maçãs.

To observe movements and activity patterns of both species, an experiment was developed in a confined area (300 x 100 cm) using a PIT telemetry equipment.

Data was collected from tagged individuals of the 2 species monitored during several days, to detect competition for food and shelter and interactions between individuals during

night and day.

The Passive Integrated Transponder (PIT) technology

PIT technology has been developed for monitoring the individual movements of free-ranging fish (Prentice et al. 1990, Greenberg & Giller 2000), mammals (Schooley 1993), reptiles

(Perret & Pierre 2002), crustaceans (Caceci et al. 1999) and also crayfish (Bubb et al. 2002). This technology is composed of PIT tags, microchips sealed inside glass capsules, which are

implanted in or fixed on the animals, and one or several antennae connected to a transceiver. The PIT tag is detected and recorded when a tagged animal pass within the read range of

the antenna which sends a unique alphanumeric code to the transceiver. Few studies have examined the use of this method to understand the behaviour and interactions between

sympatric crayfish species, namely when these populations have a significant invasive ability in the northeast streams and rivers of Portugal.

Introduction

a plastic net enclosure (300 x 100 cm) in an artificial pond was used

stones and cobbles were randomly introduced in the enclosure to promote visual isolation and refugia

food (mainly fish) was added, each 3 days, near antennae 1, 2, 3 and 4 (Fig. 1)

monitoring was made through PIT Technology; the equipment included a multi-point decoder (MPD) unit connected to

eight fixed circular panel antennae (Ø= 30 cm) located under the enclosure plastic bottom and 12.0 x2.1 mm PIT tags

(UKID Systems Ltd, U.K.); the experiment design is presented in Fig.1

the same number of crayfish was externally PIT- tagged, considering both sex and Procambarus clarkii and Pacifastacus

leniusculus species; crayfish size ranged between 8.5 and 10.5 cm

two periods: 7 to 13 July 2007 and 26 June to 2 July 2008

two different densities : 6.7 and 4 crayfish/m2 for 2007 and 2008 periods, respectively

to reduce the number of records of repetitive events, a data repeated filter of 25s was used in the MPD configuration, i.e.

if a crayfish is within the range of a particular antenna for a certain period of time, there is only one record of its presence

for each 25 seconds period

Water conditions – temperature: 21-23ºC, dissolved oxygen: 7-8 mg/L, pH: 6.9-7.2, conductivity: <75 µS/cm

Data Analysis:

observations were grouped as i) “repeated”– including all the records for the total experiment period and ii) “non-

repeated”– when there are sequences of similar sequential records (due to stationary behaviour in a particular antenna)

only one record for each sequence is retained

n-MDS and ANOSIM analyses were performed with PRIMER 6 (Clarke & Gorley 2006)

A total of 13,622 (during 7 days in 2007) and 14,914 (during 7 days in 2008) PIT-tag records were successfully

registered by the MPD unit for both crayfish groups (MPD error identification: 0.29 to 1.88%)

PIT-tag detections were higher for P. clarkii, 58.9% (2007) and 59.1% (2008), than for P. leniusculus, 41.1% (2007)

and 40.9% (2008) based on the repeated data, suggesting a dominance status by the red swamp crayfish

Interactions between crayfish species lead to the exclusion of P. leniusculus from preference positions near the

food source. P. clarkii displaced P. leniusculus from the positions near antennae 1-4

Contradictory results were obtained for the non-repeated data: P. leniusculus showed, during 2007 period (Fig. 3),

an higher movement pattern (64.8%) when compared with P. clarkii (35.2%). However, this pattern was not

observed (60% - P. clarkii vs. 40%- P. leniusculus) during 2008. Probably, the density decrease in the enclosure (from

6.7 to 4 individuals/m2) allowed P. leniusculus to remain stationary in “marginal microhabitats” avoiding agonistic

interactions and displaying a temporal and/or spatial segregation behaviour

Females tended to display a more stationary behaviour (33.5-31.4% for P. clarkii and 26.7-24.1% for P. leniusculus)

compared to males (25.3-27.8% for P. clarkii and 14.4-16.7% for P. leniusculus) for both crayfish species

The n-MDS ordination showed a better separation between both species and sex for the repeated data than for the

non-repeated data (Fig. 4). The ANOSIM one-way analysis demonstrated significant differences (P< 0.001) between

species, study years (distinct crayfish densities in the experimental pond) and sex of distinct species; no significant

differences were detected between males and females of the same species

P. leniusculus was more active than P. clarkii for all 4 periods of day; movements for both species were avoided

during day. Both species tended to increase activity under low light conditions (Table 1)

The PIT-tag technology showed to be useful in the behavioural study of the two species

under confined conditions.

Significant differences were detected in the movement and activity pattern of the two

crayfish species, apparently showing a dominant behaviour by Procambarus clarkii.

Results must be carefully analyzed, since PIT- technology has limitations: 1) small

detection range: only about 50% of area available was covered by global antenna range

detection and 2) MPD filter: two similar successive records are temporarily spaced of 25s

(for the same tag);

Experiment should be repeated with different crayfish densities in order to confirm the

dominance, movement and diel activity patterns found.