First Interim Report of the Working Group on Acoustic and Egg Surveys for Sardine and Anchovy in ICES Areas VII, VIII and IX (WGACEGG). 17-21 November 2014 Vigo, Spain
|Ref.||ICES CM 2014/SSGESST:21|
|Copyright||2015 International Council for the Exploration of the Sea|
|Contributor(s)||Masse Jacques, Petitgas Pierre, Doray Mathieu, Duhamel Erwan|
|Note||ICES WGACEGG REPORT 2014 SCICOM STEERING GROUP ON ECOSYSTEM SURVEYS SCIENCE AND TECHNOLOGY|
|Abstract||The Working Group on Acoustic and Egg Surveys for Sardine and Anchovy in ICES Areas VII, VIII and IX (previously ICES Areas VIII and IX), met in Vigo, Spain, from 17–21 November 2014. As every two years, in 2014 also MEDIAS members were invited to participate at the WGACEGG meeting; this practice, which was framed in order to promote exchange of experiences and ideas for development and collaborative work, has become regular event every second year. The meeting was attended by 27 participants from seven countries (representing nine institutes). Prior to the meeting, – on 16 November, – an informal workshop, with WGACEGG and MEDIAS members, was organized to get potential users acquainted with the EchoR software under development by Ifremer for acoustic biomass estimation data processing. Thirteen participants attended this training session. Days 1 and 2 were spend on presentations by both WGACEGG and MEDIAS participants and the remainder of the week used for general WGACEGG business and specific DEPM or acoustics issues either in plenary or parallel sessions.
Fourteen surveys (four from 2013 and 10 from 2014) were reported to the Group. The highlights from 2014 surveying showed:
• A reduced biomass of sardine in Iberian waters, in particular Cantabrian Sea, which has been corroborated by both acoustic and DEPM surveys, without sign of good incoming year class, and almost stable trend in VIIIab;
• A marked declining trend, since 2012, in both mean weight and mean age for sardine in VIIIab due to the strength of the last incoming year classes;
• Oppositely, a weak declining trend in both mean weight and mean age of sardine in VIIIc due to the lack of strong incoming year classes in the last years in Iberian waters;
• An increasing trend in anchovy biomass indices from both acoustic and DEPM in Bay of Biscay surveys; • The highest record in the JUVENA anchovy prerecruit index almost occupying the whole Bay of Biscay, being as well the highest distribution area ever reported, but with a relatively small mean length size in the westernmost area;
• An increase in clupeid fish (sardine, anchovy and sprat) in southern VII Divisions the name and the date of the meeting (the latter is very important in terms of meetings held regularly);
During the session dedicated to DEPM aspects a revision on the major pending issues was conducted and a plan of actions was delineated (Annex 8.6).
During the session addressing acoustic issues results of the intercalibration between the French RV Thalassa and the Spanish RV Miguel Oliver were reported. No significant changes were found between the performance of both vessels either in terms of acoustic records or at the fishing stations. On the other hand progress on in situ TS measurements conducted during the PELGAS cruise were also presented together with the multifrequency approach echogram post-analysis used during the PELTIC survey.
The Group endorsed the newly collected results on anchovy recruitment from the 2014 autumn acoustic survey in the BoB (JUVENA), which were subsequently made available for assessment modelling by WGHANSA.
In preparation for the 2016 sardine benchmark some members of the WGHANSA, who are simultaneously members of WGACEGG, raised the discussion on some issues related to DEPM and acoustic data available for assessment. It was decided that extra plankton samples from surveys which took place in the intermediate years between DEPM surveys will be explored in order to assess its value for egg abundance index estimation. The results on acoustic inter-calibration experiments undertaken in the past by IPMA and IEO are to be revisited and conclusions and eventual pending issues on catchability differences or other related aspects presented to the Group.
The Group planned the coordinated 2015 surveys and agreed on the timing for having the results available for assessment purposes.