A primary study on the effect of artificial disturbance on a fishing area by shrimp beam trawl

J. Kor. Soc. Fish. Tech., 45(4), 223 233, 2009 DOI:10.3796/KSFT.2009.45.4.223

A primary study on the effect of artificial disturbance on a fishing area by shrimp beam trawl

Bong-Jin C HA *, Sang-Pil Y OON

, Jae-Soung L EE

, Soung-gill K IM

, Rae-Hong J UNG

, Won-Duck Y OON

and Jong-keun S HIN

Fisheries Resources and Environment Division, West Sea Fisheries Research Institute, NFRDI, Incheon 400-420, Korea

1

Tidal Flat Research Instiute, NFRDI, Gunsan 573-882, Korea

2

Environment Research Division, NFRDI, Busan 619-902, Korea

3

Ecology and Oceanography Division, NFRDI, Busan 619-902, Korea

4

Research and Development Planning Division, NFRDI, Busan 619-902, Korea

It has been considered that fishing areas for shrimp beam trawl have been in ruin because Korean local governments have permitted trawling into the areas limited by the fisheries local regulations from 1994.

Physical and biological effects of the trawling were investigated in the study. Physical effects were investigated by optical methods such as trawling tracking by side scan sonar and comparing the gear both before and after trawling. Biological aspects were investigated by grab sampling of benthic animals, concentration of trace metals in sediment and a flux evaluation of NH 4

+

, PO 4 , and SiO 2 by coring. The fishing activity had physical impacts on the seabed but these recovered naturally in less than fourty days naturally, which increased the benthic biodiversity, increases the trace metal concentration of and nutrient flux into the seawater, especially phosphate and silicate. This method and these results can help in further studies looking for disturbances by fishing.

Key words : Fishing disturbance, Shrimp beam trawl, Trawling impact, Side scanning, Biological aspect

* Corresponding author: [email protected], Tel:82-32-724-0631, Fax: 82-32-724-0569

2004 2006 59 61

, ,

,

. , 61

.

30

(Michael, 2005),

(Malik and Mayer, 2007),

(Biasi, 2004;

Simpson and Watling, 2006),

(Duineveld et al., 2007),

(Burridge et al., 2002),

(megafaunal benthic communities) (Kaiser et al,. 1998) . FAO(Fisheries Technical paper, 2005)

.

.

, ,

, .

, 20

(side scan sonar) , ,

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(side scan sonar, S150I, DSME U-Tech, Korea)

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9 40

.

Fig. 1 b

,

Fig. 1. The area of the investigation around Gujora in Geoje island.

34 48 N

34 43 N Gujora

a

b

128 38 E 128 44 E

. Fig. 1

,

Fig. 1

a .

. Fig. 2

.

2007 4

7

Fig. 1 b Fig. 1. a

1 .

0.05m

van Veen grab

2 .

1.0mm

, 10%

.

, .

(m

) .

2007 7 Fig. 1 b

.

, HNO 3 : HClO 4 : HF=2 : 1 : 2

ICP MS (Elan 6000, Perkim Elmer) Cu, Cd, Pb, Cr, As, Zn

. 80 C ( Φ 63μm)

.

1g 50mL

(HNO 3 : HF : HClO 4 2 :

2 : 1) .

Fig. 2. Drawings and diagram of the shrimp beam trawl used in the experiment.

150

200 353 200 0.75mm

0.75mm 1.25mm 24.5mm 0.75mm

18.5mm 18.5mm

18.5mm 12m

3.6m 14.65m

3m

0.3m

12.8m

13.5mm 0.85mm

15.2m(Diameter 190mm)

P.P 3S/T Lead Rope φ24 400m

Chain φ15 30m Float φ180(A Type) P.P 3S/T Lead

rope φ24 1m P.P 3S/T Lead rope φ24 30m

Steel ripe φ50 1.2m Steel ripe

φ50 8.0m 1.3m

1.9m

2% HNO 3 100mL .

(ICP MS, Perkin

Elmer, Elan 6000) , Hg

(Milestone, AMA 254) .

Standard Reference Material PACS 2(Marine

Sediment) ,

class 100 clean room .

2007 4 Fig. 1 b

Fig. 1 a

.

(Lenght:40cm, Diameter : 8cm, Acryl)

. ,

. 0.45 m

.

, Fig. 3 (a)

Fig. 3. Detecting of recovering process of the disturbance from trawling the seabed by the side scan sonar in (a) of the Fig. 1.

(a) : Just after

(b) : 9 days after

(c) : 40 days after

.

8m ,

Fig. 4

.

3 8cm ,

6 10cm

. Fig. 3

(b) 8 11 7

Fig. 3 (c)

12 10

. , 40 . ,

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.

. Fig. 5

2

.

,

, Fig. 5

,

.

.

.

,

Fig. 4. Changing of detected parts(Ski) of the gear on the seabed after trawling.

Fig. 5. Snapshots from the recording for the ground rope

movement of the shrimp beam trawl according to time

series in the fishing area and shrimp season that was

recorded by underwater camera attached to float line

during trawling.

.

Fig. 6

, Fig. 7

, Table 1 ,

Exp (Experiment) Con

(Control) . , Exp1

, Con1 , Exp2 , Con2

. Fig. 6

58% ,

.

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.

Fig. 7 Table 1 22

44

.

. 780 2800ind./

3

Fig. 7. The species, density and diversity of polychaete Community in the experiments and controls(Con : Fishing area, Exp : non-fishing area ; Exp1, Con1 : fishing season, Exp2, Con2 : fishing off season).

Fig. 6. Ratio of the number of fauna in the experiments and controls(Con : Fishing area, Exp : non-fishing area ; Exp1, Con1 : fishing season, Exp2, Con2 : fishing off season).

100%

80%

60%

40%

20%

0%

50 40

30 20

10 0

4

3

2

1

0

No. species(taxa/0.1m

) Density(ind./m

) Diversity(H )

3000 2500 2000 1500 1000 500 0 Exp1 Con1 Exp2 Con2

Exp1 Con1 Exp2 Con2 Exp1 Con1 Exp2 Con2 Exp1 Con1 Exp2 Con2

Polychaeta Crustacea Mollusca Other

Table 1. Collected species from two sites around Geoje island(Con : Fishing area, Exp : non fishing area ; Exp1, Con1 : fishing season, Exp2, Con2 : fishing off season)

A specific species Mediomastus californiensis Magelona japonica Ampharete arctica Euchone alicaudata Sigambra tentaculata Heteromastus filiformis Ammotrypane aulogaster Glycinde gurjanovae Nephtys oligobranchia Cirratulidae sp.

Flabelligeridae sp.

Aquilaspio krusandensis Glycera chirori Paraprionospio pinnata Tharyx sp.

Polydora sp.

Sternaspis scutata Lumbrineris longifolia Minuspio multibranchiata Ophiodromus pugettensis Pseudopolydora paucibranchiata Amaeana occidentalis Aricidea neosucica nipponica Loimia medusa

Lumbrineris japonica Scoloplos armiger Eumida sanguinea Spiochaetopterus koreana Aphelochaeta monilaris Chone teres

Amphisamytha japonica Dorvillea rudolphi Lygdamis giardi Scolelepis sp.

Anaitides koreana Aonides oxycephala Cabia pilargiformis japonica Minuspio pulchra Nectoneanthes multignatha Prionospio paradisea Spiophanes kroeyeri Syllidae sp.

Cirrophorus branchiatus Diopatra sugokai Exogone uniformis Harmothoninae sp.

Nereis longior Pilargis berkeleyae Pista cristata Prionospio saccifera Amphicteis genneri Chaetozone sp.

Clymenella koreana Heterospio sinica Inermonephtys gallardi Leiochrides sp.

Lumbrineris cruzensis Mellina elisabethae Notomastus latericeus Owenia fusiformis Spiophanes bombyx Trochochaeta sp.

Total number Total Species number

Exp 1 Con1 Exp2 Con2

6 20 45 1 15

1 3 5 22

1 15

7 5 9

4 1 2 6 3 7 6 1 4 5 1 4 3 3 1 3 3 2 2 2 1 2 1 2

1 1

1 1 1 1

7 22

4 4 1 2 6

3 3 2 2 5 4 2 1 4

1

1 1

1

1

1

87 7 35

8 27 27 18 6 3 1 10

3 2 6 4 8 7 3 2

2 1

1

1 3 1

1 1

2 1

1 1

5 18

9 2 1 4 6 17

1 8 2 1 2

1 1 3

2

3 2 3

1

1 1

1 1

1

230 44

78 22

280 31

97

26

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(Kaiser et al. 1998, FAO 2005)

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, Food

Web(Marta Coll et al., 2002)

.

Fig. 8

,

. Cd Zn

,

NOAA ERL(Effect Range Low)

.

8cm, 10cm

,

. ,

,

. Fig. 8. Density of trace metals before trawling and after trawling in the fishing area and shrimp season.

150

100

50

0

0.15

0.10

0.05

0.00

Metal concentration(mg/kg) Cd. Ha concentration(ma/ka)

Ou Pb Or As Zn Hg Od Trace metal

Before

After

( , , )

Table 2 Fig. 9 ,

6 7cm

.

, 8 9cm

.

1.5 .

Fig. 9. Vertical distributions of dissolve ammonium, phosphate, and silicate in pore water of the fishing and non-fishing area. The vertical error bars represent the range of sampling depth.

Table 2. Benthic fluxes of porewater ammonium, phosphate, silicate of the fishing and non-fishing area

NH

+

PO

3

Si(OH)

(mmol m

yr

)

Fishing 12.8 0.28 13.4

Non-fishing 15.3 1.91 22.2

2 0 2 4 6 8 10 12 14 16

0 30 60 90 120 150

0 30 60 90

200 300 400 500

Fishing area NH

+

fishing

(μM) NH

+

(μM)

PO

fishing

( μM) PO

3

( μM)

Si(OH)

(μM) Si(OH)

(μM)

Non-fishing area

200 300 400 500

0 30 60 90

0 30 60 90 120 150

2 0 2 4 6 8 10 12 14 16

2 0 2 4 6 8 10 12 14 16

2 0 2 4 6 8 10 12 14 16 2 0 2 4 6 8 10 12 14 16 2 0 2 4 6 8 10 12 14 16

Depth(cm)

,

,

.

/ .

,

.

6cm

40 .

,

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,

1.5 .

,

. , Food Web

, ,

(Dounas, 2006)

.

,

.

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( , RP 2009 FE 007)

.

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2009 7 14

2009 8 26 1

2009 9 30 2

2009 11 2 3

2009 11 2