东海中华哲水蚤的年产量估算

Estimation of the annual production of Calanus sinicus Brodsky (Copepoda: Calanoida) in the East China Sea

1 997年至 2 0 0 0年在东海陆架区进行了 4个航次的大面调查 ,用获得的大型浮游生物网样品分析资料应用产量 /生物量比值 ( P/ B)法对中华哲水蚤的年产量做了初步估算。中华哲水蚤的 P/ B比值为6.735 3,在东海的平均年产量为 2 63.94C mg/ ( m2 / a)。全测区年产量为 1 1 0 .745× 1 0 3t碳 ,即 1 1万 t,相当于活体重 1 44 .3万 t。

Calanus sinicus is a widely distributed planktonic copepod in the wide ranging temperature and salinity marginal seas of the western North Pacific from Japan to Vietnam. It dominates the mesozooplankton in the East China Sea and constitutes important food for the commercially most important fish stocks (e.g. sardine, anchovy etc.) especially for their larvae. This copepod can be found throughout the year in the East China Sea but shows strong seasonal variation, with the year's maximum in early summer. Although it has been the subject of intensive research dating back to the 1950's, there are still questions about its ecology. One of the fundamental questions is what is its annual production or how much energy can be provided by this copepod to its predator each year. This work is the first attempt to estimate the annual production of C. sinicus in the East China Sea by using the biomass/production ratio method. Zooplankton samples for the measurement of C. sinicus biomass were collected during 4 cruises conducted in different season, i.e. Oct. to Dec. 1997, April to May 1998, June to Aug. 1999 and Jan. to Mar. 2000 respectively. The research area (Figure 1) covered most of the distribution area of C. sinicus in the East China Sea. Vertical tow with an 80 cm diameter plankton net was made at each of the 142 stations from sea bottom to sea surface or from 200 m depth to sea surface when the water depth was greater than 200 m. The dry weight ( DW , μg) and carbon contents ( C , μg) of C. sinicus were estimated from body length ( L , μm) by using the relationship established by Uye (1982) as log DW =2 66×log L -6 68 and log C =2 64×log L -7 00. The energy density ( Ms ) of C. sinicus we measured was 22 86 kJ/g. dry wt. The P/B ratio ( P/B ) for C. sinicus was calculated by the equation log P/B =-0 16-0 34 log Ms given by Banse and Mosher (1980) and has a value of. 6 7353. The average annual production of C. sinicus (in carbon) calculated was 263 94 mg/(m 2·a). Figure 1 shows the horizontal distribution of the annual production. The annual production in the whole research area is 110 745×10 3 t. carbon, which equals to about 1 443 million ton living animal.