An assessment of beaked redfish (S. mentella and S. fasciatus) in NAFO division 3M (with an approach to the likely impact of recent 3M cod growth on redfish natural mortality)

65 páginas, 12 tablas, 10 figuras.-- Scientific Council MeetingThe 3M redfish assessment is focused on the beaked redfish, regarded as a management unit composed of two populations from two very similar species: the Flemish Cap S. mentella and S. fasciatus. The reason for this approach is the historical dominance of this group in the 3M redfish commercial catch until 2005. However a new golden redfish fishery (S. marinus) started on September 2005 on shallower depths of the Flemish Cap bank above 300m. This new reality implied a revision of catch estimates, in order to split recent redfish commercial catch from the major fleets on Div. 3M into golden (S. marinus) and beaked (S. mentella and S. fasciatus) redfish catches. An Extended Survivor Analysis (Shepherd, 1999) was used with the same framework of previous assessments and with the tuning of the 1989-2010 EU survey. Recent survey results suggest that the beaked redfish stock has not been able to hold its growth and sustain an above average level, suffering instead a severe decline on the second half of the 2000’s. For several reasons, the most likely hypothesis to justify this unexpected downward trend on stock size is an increase in mortality other than fishing mortality. From the sensitive analysis, carried out for a set of natural mortality options, a natural mortality of 0.4 (fixed for ages 4-6 through 2006-2010, and ages 7+ on 2009 and 2011) was adopted. This is the lowest possible level of natural mortality giving assessment results in line with the recent survey declines and at the same time with key diagnostics very close to the best ones, obtained with a higher natural mortality of 0.55. A 2011-2007 retrospective XSA was also carried out. When compared to previous assessments, these retrospective present more consistent trends namely as regards female spawning biomass and average fishing mortality, coupled with a non systematic bias signal. Very high fishing mortalities until 1996 forced a rapid decline of abundance, biomass and female spawning biomass. With lower fishing mortalities since then, the stock decline was halted. The weak 1991-1997 year classes kept the stock size at a low level till 2003, basically sustained by the survival and growth of the existing cohorts. Recruitment at age 4 increased from 2002 till 2006, when the 2002 year class was at an historical high, and from 2006 to 2008 fell as fast as it went up, still continuing to decrease on most recent years and being on 2010 just bellow average. Above average year classes coupled with fishing mortalities in the vicinity of F0.1 or even lower allowed a rapid growth of biomass and abundance since 2003 and sustained the stock at a high level on 2007-2008. However the stock decreased on the last couple of years despite low catch and, being still above average level, there are no signs that the present decline rate is slowing down. Female spawning stock component experienced a similar decline. Short and medium term stochastic projections were obtained for female spawning stock biomass (SSB) under Fstatusquo (average 2008-2010 fishing mortality), together with SSB and yield medium term probability profiles. Keeping fishing mortality at its present low level well below F0.1 will sustain on the short term the female spawning stock biomass above the SSB interval from where all the abundant year classes from the past decade where generated. But on the long term it will be natural mortality to determine the future of beaked redfish as a fishery resource. The average 2012-2013 Fstatusquo catch for beaked redfish will be 2 of 3,200 tons. According to 2008-2010 observed catch data from the Portuguese, Spanish and Russian National Sampling Programmes on board, a beaked redfish annual catch of 3,200 tons would correspond to an overall 3M redfish catch (including the shallower golden redfish catches) near 7,000 tons (6,840 tons)This assessment is part of a EU research project supported by the European Commission (DG XIV, Program for the collection of data in fisheries sector), IPIMAR, CSIC, IEO and AZT

The status of redfish (S. mentella and S. fasciatus) in Divisions 3LN at present and the likelihood its follow up in the near future (under the ongoing the Management Strategy or a status quo TAC scenario)

There are two species of redfish in Divisions 3L and 3N, the deep-sea redfish (Sebastes mentella) and the Acadian redfish (Sebastes fasciatus) that have been commercially fished and reported collectively as redfish in fishery statistics. Both species, occurring on Div. 3LN and managed as a single stock, don’t belong to isolated local populations but, on the contrary, are part of a large Northwest Atlantic complex ranging from the Gulf of Maine to south of Baffin Island. The ASPIC assessment of this stock is based on the logistic form of a non-equilibrium surplus production model (Schaeffer, 1954; Prager, 1994), adjusted to a standardized catch rate series (Power, 1997) and to all stratified-random bottom trawl surveys conducted in various years and seasons in Div. 3L and Div. 3N from 1978 onwards. Both CPUE and surveys were used with all observations within each series. The 2018 assessment proceed on the threshold of the new 2014 approach, the main features of the previous input framework were kept, with MSY fixed at 1960-1985 average catch and the rest of the approved 2014 assessment framework updated. Despite its poor performance the 3L Spanish survey has been kept in the analysis due to its high correlation with the autumn 3LN Canadian survey, one of the two backbone series of the assessment. ASPIC results confirm a stable stock from the 1960’s to the first half of the 1980’s, sustaining an average yield of 21 000t. Stock declined with a sudden rise of the catch over the late 1980’s first half of the 1990’s, and started to gradually recover after catches fell to a residual level when the stock collapse. The maximum observed sustainable yield (MSY) of 21 000 t can be a long term sustainable yield if fishing mortality stands at 0.11/year, exploiting a correspondent Bmsy at 187 000 t. From assessment results there is a high probability (CL’s 80%) that the stock was at the beginning of 2018 above Bmsy, after crossing 2017 under a fishing mortality most likely below 34% Fmsy

A Revised Update of the 2014 ASPIC Assessment of Redfish (S. mentella and S. fasciatus) in Divisions 3LN (how the the stock is coping with the actual Management Strategy and its likely impact on the next coming years).

There are two species of redfish in Divisions 3L and 3N, the deep-sea redfish (Sebastes mentella) and the Acadian redfish (Sebastes fasciatus) that have been commercially fished and reported collectively as redfish in fishery statistics. Both species, occurring on Div. 3LN and managed as a single stock, don’t belong to isolated local populations but, on the contrary, are part of a large Northwest Atlantic complex ranging from the Gulf of Maine to south of Baffin Island. The present ASPIC assessment of this stock is based on the logistic form of a non-equilibrium surplus production model (Schaeffer, 1954; Prager, 1994), adjusted to a standardized catch rate series (Power, 1997) and, for the first time, to all stratified-random bottom trawl surveys conducted in various years and seasons in Div. 3L and Div. 3N from 1978 onwards. Both CPUE and surveys were used with all observations within each series. In order to proceed on the threshold of the new 2014 approach, and taking into account that since then no substantial changes appear to have occurred on the state of the stock, the main features of the previous input framework were kept, with MSY fixed at 1960-1985 average catch and the rest of the approved 2014 assessment framework updated. The 3L Spanish survey, the only ongoing survey so far outside the analysis, has now been successfully included on this assessment framework (relative inter-quartile range from bootstrap analysis for the last two assessments highlight the higher consistence of most of the 2016 assessment results when compared with the ones from 2014). ASPIC assessment results confirm a stable stock from the 1960’s to the first half of the 1980’s, sustaining an average yield of 21 000t. Stock declined with a sudden rise of the catch over the late 1980’s first half of the 1990, and increased since then, after catches fell to a residual level with the stock collapse. Assessment results also confirm that the maximum observed sustainable yield (MSY) of 21 000 t can be a long term sustainable yield if fishing mortality stands at 0.11/year, exploiting a correspondent Bmsy at 190 000 t. 2 There is a very high probability that the stock was at the beginning of 2016 at or above Bmsy , after crossing 2015 under a fishing mortality most likely at or below 50% Fmsy. There is also a very high probability that catch on 2016 at 10 400 t TAC and on 2017 and 2018 at the predicted increases approved in the 2014 Risk‐Based Management Strategy for 3LN Redfish, will keep fishing mortality on 2018 below Fmsy and biomass at the beginning of 2019 above Bmsy.Postprint0,000

The status of redfish (S. mentella and S. fasciatus) in Divisions 3LN and two medium term scenarios (when recruitment is low, Risk Based Management Strategy or common sense?)

There are two species of redfish in Divisions 3L and 3N, the deep-sea redfish (Sebastes mentella) and the Acadian redfish (Sebastes fasciatus) that have been commercially fished and reported collectively as redfish in fishery statistics. Both species, occurring on Div. 3LN and managed as a single stock, don’t belong to isolated local populations but, on the contrary, are part of a large Northwest Atlantic complex ranging from the Gulf of Maine to south of Baffin Island. The ASPIC assessment of this stock is based on the logistic form of a non-equilibrium surplus production model (Schaeffer, 1954; Prager, 1994), adjusted to a standardized commercial catch rate series (Power, 1997) and to all stratified-random bottom trawl surveys conducted in various years and seasons in Div. 3L and Div. 3N from 1978 onwards. Both CPUE and surveys were used with all observations within each series. The 2020 assessment proceed on the threshold of the new 2014 approach, with MSY fixed at 1960- 1985 average catch and the rest of the approved 2014 assessment framework updated. ASPIC results present a stock stable from the 1960’s to the first half of the 1980’s while sustaining an average yield of 21 000t. Stock declined with a sudden rise of the catch over the late 1980’s first half of the 1990’s, and started to gradually recover after catches fell to a residual level in response to stock collapse. The maximum observed sustainable yield (MSY) of 21 000 t is linked to a Fmsy at 0.11/year and a Bmsy at 185 000 t. There is a high probability (>90%) that the stock was at least 38% above Bmsy at the beginning of 2020, after crossing 2019 under a fishing mortality not higher than 46% Fmsy

Inquete sorologica do Maedi-Visna em rebanho de ovelhas Rabo Largo no Norte do Ceará.

Resumo: Maedi-Visna (MV) é uma doença de ovinos, causada por lentivírus, responsável por uma infecção de caráter progressivo, lento e persistente. As perdas econômicas são falhas reprodutivas, morte, diminuição da produção láctea e perda de peso dos animais. A enfermidade foi introduzida no Brasil por meio da importação de raças exóticas infectadas. Baseando-se na elevação do risco da disseminação da doença, objetivou-se com este trabalho determinar a prevalência de anticorpos para o vírus do MV em rebanhos de ovinos Rabo Largo criados no norte do Ceará. Para tanto, foram avaliados 64 ovinos oriundos da Fazenda Experimental Vale do Acaraú, localizada no município de Sobral-CE. Os resultados foram obtidos pela microtécnica de imunodifusão em gel de agarose e Western Blot. As amostras sanguíneas apresentaram resultados negativos para a prevalência de anticorpos do Maedi-Visna. Conclui-se com estes resultados que o rebanho está livre da infecção da MV, entretanto os órgãos fiscalizadores devem manter a vigilância para evitar a entrada dessa enfermidade nos rebanhos ovinos naturalizados. Abstract: Maedi-visna (MV) is a disease of sheep caused by lentiviruses, responsible for a progressive, slow and persistent infection. Economic losses are reproductive failure, death, decreased milk production and weight loss of animals. The disease was introduced in Brazil through the importation of exotic breeds infected. Based on the increased risk of spread of the disease, the aim of this work was to determine the prevalence of antibodies to the virus MV in Rabo Largo sheep flocks created in northern Ceará. Thus, we evaluated 64 sheep from the Experimental Farm Acaraú Valley, located in the city of Sobral-CE. The results were obtained by agar-gel immunodiffusion and Western Blot. The blood samples were negative for the prevalence of antibodies to Maedi-Visna. We conclude from these results that the herd is free of infection by MV, but the supervising agencies must remain vigilant to prevent the entry of this disease in sheep flocks naturalized

Potential Operating Models, Harvest Control Rules and Performance Statistics for the NAFO 3M Cod MSE.

This document presents a proposal of possible Operating Models (OMs), Harvest Control Rules (HCR) and Performance Statistics (PS) to carry out the Management Strategies Evaluation (MSE) for the 3M cod of NAFO. This proposal will have to be reviewed by the NAFO SC to decide the first set of OMs to test with the possible HCRs in the 3M Cod MSE

An assessment of beaked redfish (S. mentella and S. fasciatus) in NAFO Division 3M, from a biological based approach to recent levels of natural mortality (2011-2016)

The 3M redfish assessment is focused on the beaked redfish, regarded as a management unit composed of two populations from two very similar species: the Flemish Cap S. mentella and S. fasciatus. The reason for this approach is the historical dominance of this group in the 3M redfish commercial catch until 2005. However a new golden redfish fishery (S. marinus) started on September 2005 on shallower depths of the Flemish Cap bank above 300m, and the Flemish Cap cod fishery reopened in 2010. These new realities implied a revision of catch estimates, in order to split recent redfish commercial catch and by-catch from the major fleets on Div. 3M into golden (S. marinus) and beaked (S. mentella and S. faThe Extended Survivor Analysis assessment used as tuning file the 1989-2016 EU survey abundance at age matrix included in a revised input framework. Continuing pressure over Flemish Cap redfish stocks by cod predation, at levels higher, or much higher, than the levels prior to 2006 lead to higher natural mortalities since then. In order to include an independent approach to natural mortality in the sensitivity M framework, for the more recent years (2011-2016) natural mortality has been estimated from a number of different biological models, some size/age-independent and others size/age-dependent. These different estimates were arranged in two sets and tuned to survey at age data. A natural mortality of 0.1 on 2015-2016 and the natural mortalities adjusted on previous assessments were found to be the most suitable option to M input. A 2017-2013 retrospective XSA was performed, confirming the consistency of the present with preceding results as regards stock biomass, female spawning biomass and fishing mortality.sciatus) redfish catches. Above average year classes and high survival rates allowed a rapid growth of biomass and abundance 2003 onwards, pulling the stock to a 2008-2010 high. Since 2009 abundance went down for causes other than fishing, being still above the 1990’s low in 2016. By the turn of the decade stock biomass and female spawning biomass (SSB) shown marginal declines as well, but reversed on 2011-2012. Individual growth of survivors and low fishing mortalities sustained stock biomass and SSB at high levels till 2015-2016. Recruitment at age 4 increased from 2002 till 2006 and was maintained at a maximum level till 2009. Recruitment declined since then and is kept on 2015-2016 at the low of the weak year classes from the 1990’s, while SSB is still well above the size that originated the high 2002-2006 recruitments. Despite the significant decline so far natural mortality has not flattened yet. If natural mortality and fishing mortality stay at their most recent levels, the actual high of female spawning biomass can hold on 2018-2019. But on the long term it will be natural mortality, namely over pre recruited ages, to determine the future of beaked redfish as a fishery resource. On 2015 STACFIS remind that projections are based in the assumption that natural mortality stay at its most recent level on the present year and at least on the two next coming years. And that, taking into account the uncertainty on the present and future level of natural mortality, its impact on female spawning stock biomass at the end of any projection is unknown. On 2017 these constraints are still in place, and therefore short and medium term projections are not presented.Versión del edito