Comparative analysis of the Inland Sea of Japan and the ... · sp. ESD=38 μm. Polyp’s main food: Microzooplankton. Food supply （µg C/L） Ingestion rate （ µg C/ind/h ）

Comparative analysis of the Inland Sea of Japan and the Northern Adriatic Sea: Can

changes in anthropogenic pressure disclose jellyfish outbreaks?

Shin-ichi Uye1, Alenka Malej2

and Tjasa Kogovsek21Graduate School of Biosphere Science, Hiroshima University, Japan2Marine Biology Station, National Institute of Biology, Slovenia

Inland Sea of Japan

ᠡ

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Ç™Ç±ÇÃÉsÉNÉ`ÉÉÇ¾å©ÇÈÇžÇ½Ç…ÇÕïKóvÇ-ÇÅB

Northern Adriatic Sea

Comparison: the Inland Sea of Japan (ISJ)

vs the Northern Adriatic Sea (NAS)

ISJ NASArea (km2) 23,202 19,000Average depth (m) 38.0 34.0Volume (km3) 881.5 635Annual river flow

volume (km3/yr) 50,000 90,000

Rain catchment area (km2) 47,895 118,000Water residence time (months) 15 2~3Annual temperature range (oC) 10~28 10~26Median

chlorophyll a biomass (mg/m2) 2 2

Annual primary production (g C/m2/yr) 285 90

Population (million) 30 25

Polls of

1,152 fishermen with ≥20 years of experience: “Did Aurelia aurita medusae increase?”

Respondents:35%: “No”,

65%: “Yes, particularly

after the 1990s”

0

20

40

60

80

100

<1982 1983-1987 1988-1992 1993-1997 1998-2002

Res

pond

ents

(%)

Increase of Aurelia aurita medusae

in

the Inland Sea of Japan

NoYes

Increase of Aurelia aurita medusae

in

the Northern Adriatic Sea (Gulf of Trieste)

0

2

4

6

8

10

12

14

16

2000 2005 2010199519901985

Based on monthly

monitoring of relative

abundanceA

nnua

l rel

ativ

e ab

unda

nce

(∑(le

veln

o. x

mon

ths)

)Level 0: absent, Level 1:

present but few,

Level 2:

several, Level 3: many (bloom)

Effect of temperature and food supply on polyp reproduction rate

Food supply

TemperatureDuration: 35 days

Eutrophication

War

mingBud

(from Han and Uye, 2010)

Water temperature change

Inland Sea of Japan

Northern Adriatic Sea

2

2-2

-2

-1

-1

1

1

0

0Tem

pera

ture

ano

mal

ies

(o C)

1950 1960 1970 1980 1990 2000 2010

Eutrophication or oligotrophication

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１９７０１９８０１９９０２０００１９７５１９８５１９９５２００５

Ann

ual r

ed-ti

des

Red-tidesRed-tides with fish

mortality

(from Setouchi net)

Inland Sea of Japan

Northern Adriatic SeaIn the 1970s and 80s, eutrophication was considerable (e.g.

frequent red tides, high chlorophyll concentrations and proliferation of benthic algae

such as Ulva).

In late 1980s and 90s, measures (e.g. sewage treatment, ban of P in detergents, modified practice of agriculture) were

taken

to result

in oligotrophication

１９７3: Enactment of the

Special Law

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0 500 1000 1500

Ciliate biomass (μgC/L)

Feed

ing

rate

(μgC

/ind/

h)

FavellaStrombidinium

MyrionectaCurve fit

Favella spp.ESD=55 μm, 46 μm

Myrionecta rubra ESD=21

μm

Strombidium sp. ESD=38 μm

Polyp’s main food: Microzooplankton

Food supply （µg C/L）

Inge

stio

n ra

te （

µg C

/ind/

h）

Microzooplankton may increase in local areas:Local eutrophication Change in nutrient (N, P, Si) compositionDominance of microbial food chain

（fromT. Kamiyama)

Polyp’s habitat: Undersurface of artificial structures

6 m

48 m

Installed on 9 April, 2010

0

5

10

15

20

J J A S O N D J F M A M2010 2011

Polyp density (polyps cm-2)

Strobilation (% of polyps)



23 million ephyrae released

EphyraePolyps



Estuary

Artificial

Natural

Half-Natural

In 1978, total length of artificial coastline:

2,925 km (43.6%) In 1996, total length of artificial coastline: 3,533 km (48.9%)

In 1996

Marine

constructions: Artificial coastline

Polyp colonies in Port of Koper, Slovenia

Dock pillarsPotential number of ephyrae

released from the polyp population in Port of Koper:

50 billion ephyrae

Oysters

Strobilated polyps

Ship dock

N

S

W E

0 8040 km

Marine

constructions:

Offshore oil/gas platforms



http://mw2.google.com/mw-panoramio/photos/medium/9399938.jpg

2000~1990~991980~891970~791960~69

Cumulative

no.6

196094137

0

10

20

30

40

5019

5119

5319

5519

5719

5919

6119

6319

6519

6719

6919

7119

7319

7519

7719

7919

8119

8319

8519

8719

8919

9119

9319

9519

9719

9920

0120

0320

0520

0720

09

Fish catch in the Inland Sea of JapanA

nnua

l lan

ding

(104

tons

)

Fish catch in the Northern Adriatic SeaIn Slovenia

In Chioggia, Italy

Ann

ual l

andi

ng (t

ons)

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Fish-dominated ecosystem

Ecosystem

change in the Inland Sea of Japan

0

10

20

30

40

50

Fish

cat

ch (x

104

tons

)

1960 1970 1980 1990 2000 2010

Fish-dominated



Jellyfish-dominated ecosystem



Jellyfish-dominated

WarmingMarineconstruction

Overfishing

Eutrophication?



Fish-dominated ecosystem

Ecosystem

change in the Northern Adriatic Sea

1960 1970 1980 1990 2000 20100

10

20

5

Fish

cat

ch (x

103

tons

)

15

25

1950

Fish-dominated



Jellyfish-dominated ecosystem



Jellyfish-dominated

Warming?Eutrophication?

Marineconstruction

Overfishing

Acknowledgements

This study was conducted under Japan- Slovenia bilateral project on jellyfish bloom.

Funding also from:1) Slovenian Research Agency (P1-0237)2) EU FP7 project PERSEUS (No. 287600)3) Japan Society for Promotion of Science4) Agriculture, Forestry and Fisheries

Research Council, Japan (project name: STOPJELLY)

Documents

Comparative analysis of the Inland Sea of Japan and the ... · sp. ESD=38 μm. Polyp’s main food: Microzooplankton. Food supply （µg C/L） Ingestion rate （ µg C/ind/h ）