39 research outputs found
Assessment of the Cod Stock in NAFO Division 3M
An assessment of the stauts of the cod stock in NAFO Division 3M is performed. The same model used last year, a Bayesian model, is used to perform the assessment. Results indicate another reasonable recruitment value in 2008 and a fairly substantial increase in SSB, reaching a median value above the Blim for the first time since 1995. The six-years retrospective plot shows that the recruitment is over estimated year by year, and that if we assume a prior distribution under the natural mortality the retrospective pattern seems no to converge, so the model running with M constant equal to 2 is presented too. It results are no significantly different as those assuming M with uncertainty. Three year projections indicate that fishing at the low Fbar level currently estimated for 2008 should allow SSB to increase to higher levels than estimated for the late 1980's, although in terms of abundance the stock will remain at lower levels. If the fishing mortality were return to the levels seen until 1995, stock recovery would become very improbable
Report of the NAFO Working Group on Improving Efficiency of NAFO Working Group Process (E-WG) Meeting
The Chair, Fred Kingston (NAFO Secretariat) opened the meeting on Thursday, 18 March 2021 at 10:00 hours. The Chairs and co-Chairs of the NAFO Working Groups were welcome to the virtual meeting (Annex 1)
Results on Northern hake Spanish discard sampling programme
Quarterly discards estimates for the Spanish bottom otter trawl fleet fishing
in the Northeast Atlantic ICES Subareas VI and VII are presented for hake
(Merluccius merluccius). Information was obtained by observers on board
under different discard sampling programmes carried out by the Spanish
research institute IEO. Raising based on effort (number of trips) was used to
estimate total quarterly discards in weight and number for the fleet.
Discards length distributions are also presented. Both in terms of weight
and numbers discards present high variation in time, ranging from 0 to
1100 tonnes and from 0 to 12 million fish. Length distributions of discarded
hake show that most of the individuals are juvenile fish, although some
individuals above the minimum landing size (27 cm) are also discarded.
Increases in the number of juveniles discarded are evident after year 2003
Applying a Bayesian model incorporating discards in the assessment of four-spot megrim (Lepidorhombus boscii) Southern stock
Since 2003 when the DCF started at European level by countries, discards data are
available for many stocks. Four-spot megrim is traditionally assessed with XSA (extended
survivor analysis) which does not include discards. For this species, discards
in number are very important, being around the 60% of total catch. A Bayesian model
incorporating discards was realized for the hake stock in ICES Divisions VIIIc and
IXa by Fernández et al. (2010). This model was also designed to produce a complete
time-series of discard estimates. Final run of the model is compared with results from
XSA performed in the working group of 2010, showing that mayor differences are in
the fishing mortality for younger ages, being higher incorporating discards data
Estimation of the reference points for the different OMs in the Cod 3M MSE
This paper presents different methods to estimate the reference points (Blim, Bmsy and Fmsy) to be used in
the 3M NAFO cod MSE. Reference points should be specific for each of the possible realities, what defines the
different possible realities are the different OMs and, within each OM, the different iterations. The methods
presented here try to estimate the reference points by iteration for the different OMs since it is assuming that
the reference points will be interpreted as a characteristic of the “real” population. The results of some of the
methods proposed to estimate the management reference points (limit and target) seem to be not consistent
between them. The results show that in this case the proxy used as Fmsy (F30%SpR) seems quite reasonable
Standardized CPUE Indices for Greenland Halibut in NAFO Regulatory Area of Divisions 3LMNO Based on Spanish Commercial Catch Rates
A standardized CPUE series using a log-linear model for Greenland halibut in NAFO Regulatory Area of
Divisions 3LMNO, based on catch and effort data from the Spanish trawl fleet since 1992 is presented. Fixed factors
considered in the model were year, month, division, depth stratum and vessel and the interactions included were
division*month and division*depth stratum. All of these factors and interactions are statistically significant. The
total proportion of variance explained by this model is 46%. The results indicate substantial variability of CPUE
over time, with several short periods of increasing and decreasing CPUE. After having reached the lowest value of
the series in 2004, standardized CPUE has increased very substantially, reaching a value in 2006 very near the
maximum of the entire series
Assessment of the Cod Stock in NAFO Division 3M
An assessment of the cod stock in NAFO Division 3M was conducted using a Bayesian SCAA (statistical catch-at-age) model. The STACFIS catch estimates and the Flemish Cap survey indices were used to fit the model. Blim, defined as the SSB of 2007, was estimated at 15 408 t (median). Results indicate a general increase in SSB since 2005 to the highest value in 2017, decreasing sharply since then. SSB has been above Blim since 2008. Between 2013 and 2018 recruitment was at very low levels; the 2016 and 2018 values were among the lowest of the series; as a consequence, 3-year projections indicate that total biomass will decrease during the projected years, while the SSB could increase under some scenarios in the final projected year. Depending on the projected scenario, probability of SSB being below Blim in 2023 and 2024 is high (≥12%) or very low (≤5%). An increase in recruitment occurred in 2019 and 2020, reaching the 2008 level.Versión del editor
Report of the NAFO Commission Ad hoc Working Group to Reflect on the Rules Governing Bycatches, Discards and Selectivity (WG-BDS) in the NAFO Regulatory Area Meeting
The meeting was opened at 10:05 hours (Atlantic Daylight Time in Halifax, Nova Scotia) on Monday, 12 July 2021 by the Chair, Temur Tairov (Russian Federation). He welcomed representatives from Canada, Denmark (in respect of Faroe Islands and Greenland), European Union, Iceland, Japan, Norway, United Kingdom, and the United States of America. The SC Chair and the STACTIC vice Chair were also in attendance (Annex 1)