International Council for the Exploration of the Sea
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posted on 2006-01-01, 00:00 authored by ICESICES
The Workshop on Mackerel and Horse Mackerel Egg Staging and Identification [WKMHMES] met in Lowestoft, England, UK, from 23–27 October 2006 to address six Terms of Reference (Section 1.2).Highlights• A number of excellent presentations were given prior to the practical aspects of the Workshop commencing. These included the use of image analysis systems for the automatic measuring of fish egg and oil globule diameters. This imaging technology is advancing rapidly, and participants were encouraged to maintain and develop an interest in this area for its potential use as an aid in the identification and staging of fish eggs. Other presentations described a DNA technique for the identification of fish eggs to species, the apparent dramatic increase in the population of Snake Pipefish (Entelurus aequoreus (L.)) and the standardisation of Bongo nets for use on the mackerel and horse mackerel egg surveys (See Section 6 for abstracts).• The ‘spray technique’ for the removal of fish eggs from preserved plankton samples was again tested for efficiency, following the preliminary trials conducted at the 2003 Workshop (ICES, 2004). The results were encouraging, particularly once initial problems had been discussed and addressed.• The majority of the time at the Workshop was spent identifying and staging mackerel, horse mackerel and similar eggs. The results promoted discussion and highlighted specific problem areas. These discussions led to the further development of standard protocols, and enhancements to the species and stage descriptions. The results were very re-assuring and similar to those obtained at the 2003 workshop. There was a slight under-estimate of stage 1 mackerel eggs (stages 1a and 1b combined) during the first round of analysis (−2%) and a slight over-estimate (2%) during the second round. The results for stage 1 horse mackerel eggs were similar with under-estimates of −2% and −1% respectively. This is particularly re-assuring as it is this stage on which the egg production estimates are based.• Whilst the egg workshop was being conducted some histology training and inter-calibration took place under the instruction of Mr Peter Witthames (Cefas). This proved beneficial to all concerned and as a result enhancements were made to the WGMEGS survey manual (Annex 5) and an adult fish sampling and fecundity estimation manual was produced (Annex 6).


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