北海道南西部磯焼け海域におけるホソメコンブ群落の形成機構  [in Japanese] Mechanisms for Kelp (Laminaria religiosa) Forest Development on the Barren Ground, Along the Southwest Coast of Hokkaido, Japan  [in Japanese]

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Abstract

北海道南西部の日本海沿岸は、磯焼け状態にある。キタムラサキウニが高密度に分布し、ホソメコンブの生育は極浅海域に限られる。餌料不足によりウニ類の成長不良が起こり、沿岸漁業に深刻な影響を及ぼしている。磯焼け海域におけるコンブなど海藻群落の形成機構を解明するため、1998年から1999年の1年間、忍路湾で、波浪、水温、ウニ、海藻の分布の季節的な変化を調査した。ホソメコンブ群落を形成するには、冬期は時化に伴う底面波浪流速の増加でキタムラサキウニが深所へ移動し、摂餌圧が低下することで、着生したホソメコンブの幼芽が保護されることと、夏期は凪ぎに伴う底面波浪流速の低下によりウニ類の摂餌圧が増加し、着生した多年生海藻の幼芽が摂食され、遷移が妨げられることが繰り返される点が重要である。磯焼け海域におけるホソメコンブ群落を造成する方法として、1)フェンスによるウニ食圧の制御、2)嵩上げ(かさあげ)による流速の制御、の2つを提案した。

The barren ground, so-called Isoyake in Japanese, maintained at south-west coasts of the Sea of Japan,Hokkaido, Japan. In the Isoyake area, the sea urchin, Strongylocentrotus nudus, dominate on the bed rock, andoccurrence of the kelp, Laminaria religiosa, was limited in the refuge at shallower zones. Fisheries in the coastshad large problem that the sea urchin could not grow up to the commercial size with inadequate foods. To developthe kelp forest technology in the Isoyake area, seasonal change of some environmental factors, water movement,water temperature, vegetation, and distribution of grazer, were observed continuously during 1998 to 1999 inOshoro Bay. Environments for occurrence of kelp forest were characterized ; the sea urchins took refuge indeeper zone from strong water movement and buds of the kelp were protected from over grazing pressure duringWinter. Moreover destructive pressure of the sea urchin occurred on kelp bed with no strong water movementand rock bed for kelp (amual algae) was protected from occupied of peremial algae during summer. We proposedtwo methods to increase the kelp forest in Isoyake area. 1) Seasonal control of excess grazing pressure usingfence. 2) Adjust the depth with block and stone to remove the urchin by increasing velocity.

Journal

  • Journal of Fisheries Engineering

    Journal of Fisheries Engineering 38(2), 159-165, 2001-10-25

    The Japanese Society of Fisheries Engineering

References:  19

Cited by:  10

Codes

  • NII Article ID (NAID)
    10008274175
  • NII NACSIS-CAT ID (NCID)
    AN10278554
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    09167617
  • NDL Article ID
    5992398
  • NDL Source Classification
    ZR26(科学技術--農林水産--水産)
  • NDL Call No.
    Z18-1327
  • Data Source
    CJP  CJPref  NDL  J-STAGE  JASI 
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