吕四渔场近岸产卵场鱼卵的种类组成与数量分布

为了解吕四渔场鱼卵种类组成和生物密度分布，2008年4月至7月在吕四渔场（32°～34°N）底拖网禁渔区线内侧布设了31个站位，进行了4个航次鱼卵调查。调查共发现鱼卵12种，4月鱼卵优势种为日本鲭（Scomber japonicus），5月为鳓（Ilisha elongata），6月和7月均为鳀（Engraulis japonicus）。垂直网采样鱼卵平均生物密度为1．71 ind·m-3，5月生物密度最高为2．77 ind·m-3，6月最低为0．566ind·m-3，4月和7月居中，分别为2．06ind·m-3和1．35ind·m-3；水平网采样鱼卵平均生物密度为6．675ind·min-1，4月生物密度最高为12．484ind·min-1，其次为5月（6．916ind·min-1）和7月（5．323ind·min-1），6月最低（1．977ind·min-1）。吕四渔场鱼卵分布的主要特点是北部海区多于南部海区。

Species composition and biomass distribution of fish eggs at inshore spawning site of Lüsi fishing ground

From April to July, 2008, by setting up 31 survey stations within the closed fishing area for bottom trawl fishery in Ltisi fishing ground （32°～34°N） , we conducted 4 investigations to study the species composition and biomass distribution of fish eggs in that area. Altogether fish eggs of 12 species were found. The dominant species are Scomberjaponicus （April） , Ilisha elongata （May） , Engraulisjaponicus （June and July）. The average biological density of fish eggs vertically is 1.71 ind-m-3 （2.06 ind·m-3 in April, 2. 77 ind·m-3 in May, 0. 566 iud·m-3 in June and 1.35 ind-m 3in July） , while the average biological density horizontally is 6. 675 ind·min-1 （ 12. 484 ind·min-1 in April, 6. 916 ind·min-1 in May, 1. 977 ind·min-1 in June and 5. 323 ind·min-1 in July）. The fish eggs in Lfisi fishing ground distribute more in the north than in the south.