OTOLITH MICROCHEMISTRY OF MARBLED FLOUNDER IN TOKYO BAY , JAPAN - - PowerPoint PPT Presentation

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Apr 11, 2024 108 likes •301 views

OTOLITH MICROCHEMISTRY OF MARBLED FLOUNDER IN TOKYO BAY , JAPAN Katayama S. and Ishii M. Keywords: Otolith microchemistry, Hypoxic stress 2017/12/13 Marbled frounder 2011 Ijmuiden Pseudopleuronectes yokohamae Several populations showed

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OTOLITH MICROCHEMISTRY OF MARBLED FLOUNDER IN TOKYO BAY , JAPAN Katayama S. and Ishii M.

2017/12/13

Keywords: Otolith microchemistry, Hypoxic stress

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2011 Ijmuiden Several populations showed synchronized interannual variations in abundance, in spite of the genetic differentiation.

Marbled frounder

Pseudopleuronectes yokohamae

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Purposes: Though the fishery targeting the flounder had been closed in the several years, the stock has not recovered in Tokyo Bay. In the research project on the ecosystem-network, we examined population structure of the flounder in and around Tokyo Bay by otolith microchemistry.

2017/12/13

50 100 150 200 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 C atch ( ton) Kanagawa Pref .

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2017/12/13

Characteristics of marbled flounder life >>>Adhesive demersal eggs >>>Habitat in bottom layer at drifting phase

Ontogenetic distribution and juvenile migration to escape from hypoxic waters in Tokyo Bay >>>See poster session HOW DOES MARBLED SOLE (PLEURONECTES YOKOHAMAE) RELATE TO TOKYO BAY SURROUNDED BY THE METROPOLITAN AREAS Ishii, M., Kajiyama, M., Katayama, S., Hori, M.

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OTOLITH MICROCHEMISTRY OF MARBLED FLOUNDER IN TOKYO BAY , JAPAN

Sr analysis (EPMA) did not indicate area- specific traits in the otolith. We employed other methods which revealed environmental history. ⇒ LA/ICP-ms analysis of multi-elemant traces

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Otolith

Profile along annuli

ICP-MS

Laser abration Element composition of

tolith in geranal (wt %)

Ca: 38.8% Sr: 0.236% Na: 0.223% K: 0.0282% Mg: 0.0021% Ba: 0.00029% Cu: 0.000074% Zn: 0.000047% Cd: 0.0000023% Causes on the fluctuation in elemental concentration, except for Sr, have been disclosed. They may display area-specific traits

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50 100 Ca Sr Na K Mg Ba Cu Zn Cd Mn

Detectable metals

LA/ICP-MS analysis Profile were obtained scan data Interval 50μm, Spot diameter 30μm, wave length 213nm Ca, Sr, Na, K, Mg, Ba, Cu, Zn, Cd, Mn

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Outside of Tokyo Bay

0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca

Relatively stable at low level Core → → Edge

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0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca

Inner area Left: 2009, right: 2011 year class Annulus Mn showed sudden increase during 0+ life period. Mn and Mg sycronizely decreased after 1+. Core → → Edge

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0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca 0.5 1 Ba/Ca Mn/Ca Mg/Ca

Mn and Mg show synchronized fluctuations. Sudden increases occur in Mn. Mid-area Left: 2009, right: 2011 year class Annulus

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Dragonet ハタタテヌメリ Callionymus valenciennei TL:50-70mm（0+） Goby ヒメハゼ Favonigobius gymnauchen TL:40-60mm（0+） Collected in early April in 2016 Water depth 5-10m

To examine the factors of fluctuations in the otolith microchemistry, coexisted demersal fishes were analyzed.

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Mid-area, Dragonet 20160405 Mid-area, Goby 20160405 Core → → Edge Core → → Edge

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Inner area, Dragonet 20160402 Mid-area, Dragonet 20160405 Mn and Mg show synchronized fluctuations. Sudden increases occur in Mn and Mg.

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Inner area Mid-area Outside

0.2 0.4 0.6 0.8 1 1.2 Mn/Ca

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 A1 A2 A3 B2 B3 B5 C5 C6 D1 D2 D3 CH1 CH2 CH3 Mn/Ca

Inner area (Dragonet) Mid-area (Goby) Mid-area (Dragonet)

Marbled flounder Dragonet, Goby

Large fluctuations within otoliths, among areas, and among fish species >>> Hypoxic waters and/or the environmental stresses occurred in the inner bay.

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Total length (mm) Before hypoxic treatment After the treatment Cont. 42.3 mm (±3.5) 45.9 mm (±4.4) Treat. 48.6 mm (±2.5) Body weight (g) Cont. 1.04 g (±0.32) 1.35 g (±0.33) Treat. 1.58 g (±0.25) Hypoxic treatment, 45-50%

f oxygen concentration, for
vernight of three times

Rearing experiment

Transportation to the laboratory

Submission of this abstract

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2017/12/13

Measured spots of otolith formed under low oxygen

ALC-marking at the commence of hypoxic experiment Sr marking at the end of hypoxic experiment

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Control Hypoxic treatment

Ba/Ca Mn/Ca Mg/Ca Ba/Sr Mn/Sr Mg/Sr Core → Edge Core → Edge Ba/Ca Mn/Ca Mg/Ca Ba/Sr Mn/Sr Mg/Sr

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During the treatment

Hypoxic stress made significant increases of Mn and Mg in the otoliths.

My assumption were confirmed, after my submission of abstract.

Before hypoxic treatment

Control

Mn/Ca Mg/Ca Ba/Ca

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Conclusions Through the LA-ICP/ms analysis, significant difference was detected between the flounder from the inside and the outside of Tokyo Bay. Otolith from the outside had little amount of trace metals, whereas high concentrations of Mn, Mg and Ba were found from the inside. These metals showed large fluctuation within otoliths, among areas, and among fish species, suggesting that these variations would depend on hypoxic waters and/or the environmental stresses occurred in the inner bay. Through the rearing experiments, hypoxic stress made significant increases of Mn and Mg in the otoliths. Otolith microchemistry of demersal fishes such as flatfishes provides a new insight for understanding environmental effects on the fishing grounds and nursery areas suffered from the spread of oxygen-depleted water in inner bays.