Results from Bottom Trawl Survey on Flemish Cap of June-July 2021

A stratified random bottom trawl survey on Flemish Cap was carried out from 12 July to 9 August 2021. Following the same procedures as in previous years, the area surveyed extends up to depths of 800 fathoms (1460 meters) and 181 fishing stations were planned. The survey was carried out by the R/V Vizconde de Eza with the usual survey gear (Lofoten). A total of 181 valid hauls were made, 120 up to 730 meters depth and 61 up to 1460 meters. Survey results are presented, including abundance indices of the main commercial species and age distributions for cod, redfish, American plaice, Greenland halibut, roughhead grenadier, squid and shrimp. The general indexes for this year are estimated taken into account the traditional swept area (strata 1-19, up to depths of 730 m.) and the total area surveyed (strata 1-34, up to depths of 1460 m.).Versión del editor

A review of NAFO 3LMN roughhead grenadier (Macrourus berglax Lacepède, 1801) reproductive biology including the evaluation of maturity ogive estimates.

A collection of 4770 histological slides collected in NAFO divisions 3LMN in a depth range from 200 to 1500 m and covering a time period between 2001 and 2015, has been reviewed to obtain information on reproductive biology of Macrourus berglax. Especial attention has been paid in atresia because its potential impact on stock productivity. Spatial and temporal variability of size and age at maturity of female roughhead grenadier was analyzed in NAFO divisions 3LMN based on microscopic maturity staging and individual age readings. Spawning capable females are homogeneously distributed nearly year-round, but in scarce numbers what prevent to define a spawning season. This statement united to the high levels of atresia could indicate a reproductive migration. We observed a clear decrease in length at first maturity (L50) of females from 27.8 cm in the period 2005-2011 to 25.6 cm in the last four years. The age at first maturity, A50, varied between 13.1 and 15 years, and there is not an evident trend of change over the years.Postprint0,000

High accuracy 234U(n,f) cross section in the resonance energy region

New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n_TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux