"Eri" and "yana" are Japanese terms for popular and traditional stationary fish traps used along the coast of Lake Biwa. "Eri" are laid inshore so as to face the lake or lagoons, or placed in the estuaries of rivers flowing into the lake. Today both are used almost exclusively for young "ayu" (sweetfish) or "ayu" fry, however, before the early 1970s, these traps were important means to catch various kinds of fish in both the lake and its lagoons. While "eri" were privatized long ago, "yana" can still be observed in cooperative or community-based fishing locations such as Kita-funaki in Adogawa Town, Shiga Prefecture. The aim of this paper is to discuss part-time fishermen who supplement their main job in part-time agriculture or other forms of employment, and who are in this respect quite different from the full-time fishermen of Katata in Ohtsu City. In this way, they seek to secure a stable income with less labor and energy input. Speaking analogically, then, we can recognize features of "eri" and "yana" in wet-rice farming technology which has similar social aspects. Here, the author discusses the potential nature and implication of their transformation, as well as changes in the context of local folk society. Lastly, from the viewpoints of both biological- and cultural- diversity and the ownership of resources, the author wishes to warn against the recent trend of over-specialization in the fishing of ayu fry. In these regards, the author recommends the further development of local environmental education and an improvement in the distribution system of "ayu" fry. エリとヤナは琵琶湖沿岸における伝統的定置漁具である。エリは湖岸線や内湖と呼ばれる琵琶湖に付属するラグーンに設置され,ヤナは琵琶湖に流入する河川の河口に設けられる。現在の両漁具での水揚高の大半は稚アユ(アユ苗)である。しかし1970年代前半までは,これらの漁具で捕っていたのはもっと多様な魚種(フナ,コイなど)であった。エリは早くに私有化されたが,ヤナは安曇川河口の北船木にみられるような共同体での維持管理が現在でもされている。 本論文の目的は,農業やそのほかの職種を主業とする兼業漁民の社会的な性格を,大津市堅田の専業漁民と対比させながら論じることである。彼らはより少ない労力・エネルギー投入量で,安定した収入を得ようとする指向が強い。これらの漁法は,技術的にも,社会的にも,水田稲作のアナロジーが適用できると筆者は考えている。本稿ではそのようなエリとヤナの,地域社会における民俗的コンテクストからその潜在的な性格と意義を議論した。 後半では,稚アユへの過度な特化が,生物的・文化的多様性や資源所有の面からきわめて問題が多いことを論じ,この観点から,環境教育や稚アユの流通システムの問題点にも言及する。