Survey : CIRO/07/1971 (part of CEFAS Historic surveys)

This survey was undertaken by Cefas as part of the CEFAS Historic surveys;

Station and biological data collected during research surveys carried out by
Cefas (formerly Directorate of Fisheries) in seas around the UK, mostly in the
North Sea, since 1902. The survey hauls are not laid out systematically as a
grid, as in current International Bottom Trawl Surveys (IBTS) and are widely
distributed over (especially) southern and central North Sea areas. Gears and
protocols were not standardised throughout, due to the long term nature of the
series. Surveys took place in each season. Data are lacking for the periods of
both World Wars. In some periods (e.g. the early 1900s), all species caught
were recorded, whereas in other periods (e.g. 1920s-30s), only the key
commercial species (e.g., Plaice, Sole and Cod) were recorded systematically.
Note that some surveys targeted particular species (notably Plaice).

Survey took place between 17/08/1971 and 14/09/1971 on Cirolana

Equipment used during this survey :

- Engels trawl codend catch
- Frame Trawl BoothBay Inverted 1 strop, 3 depressors, Fryma Net

Survey operations were undertaken on 74 stations

23 different species were caught on this survey

本次调查由英国国家渔业研究机构（Cefas，原名渔业署）发起，作为Cefas历史调查项目的一部分。自1902年起，Cefas在围绕英国的海域，尤其是在北海，开展了多项研究调查，积累了丰富的站点和生物数据。与当前的国际底拖网调查（IBTS）不同，本调查的捕获数据并非按网格系统有序排列，而是广泛分布于北海的南部和中部地区。由于调查系列的长期性质，设备和协议并未实现标准化。调查覆盖了每个季节，但两次世界大战期间的数据缺失。在某些时期（如20世纪初），所有捕获的物种均被记录，而在其他时期（如1920年代至1930年代），仅系统地记录了关键的商业物种（例如，比目鱼、鳎鱼和鲭鱼）。值得注意的是，某些调查专注于特定物种（尤其是比目鱼）。1971年8月17日至9月14日，在Cirolana进行了调查，使用的主要设备包括Engels拖网、Frame Trawl BoothBay倒置式1根绳索、3个沉子以及Fryma网。调查在74个站点进行，共捕获了23种不同的物种。