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[EN] In this study, a multispecies gadget model (GadCap) simulating the interactions among the Flemish Cap cod (Gadus morhua), redfish (Sebastes spp.), and shrimp (Pandalus borealis) has been incorporated as the operating model in a management strategy evaluation (MSE) framework (a4a-FLR) to test the performance of multiple combinations of harvest control rules (HCRs) for the three stocks when recruitment uncertainty and assessment error are accounted for. The results indicate that due to the strong trophic interactions, it is not possible to achieve the precautionary exploitation of all the stocks at the same time. Maintaining shrimp biomass above the limit reference point (B) would require unsustainable fishing pressure on cod and redfish to reduce predation mortality. In contrast, maintaining cod biomass above B would involve high predation on and high risk of collapse of the shrimp and redfish stocks. The implementation of alternative two-stage HCRs would reduce predation, resulting in higher productivity and lower probability of collapse for cod and redfish. The results of this study support the need of accounting for species interactions when designing management strategies for a group of interdependent commercial stocks. Copyright © 2023 Canadian Science Publishing, [FR] Un modèle multi-espèces Gadget (GadCap) qui simule les interactions de la morue (Gadus morhua), des sébastes (Sebastes spp.) et de la crevette nordique (Pandalus borealis) sur le bonnet Flamand a été intégré comme modèle d’exploitation dans un cadre (a4a-FLR) d’évaluation de stratégies de gestion (ESG) afin de valider la performance de différentes combinaisons de règles de contrôle des prises (RCP) pour les trois stocks quand l’incertitude reliée au recrutement et l’erreur d’évaluation sont prises en compte. Les résultats indiquent que, en raison des fortes interactions trophiques, l’atteinte de l’exploitation prudente simultanée de tous les stocks n’est pas possible. Le maintien d’une biomasse de crevette supérieure au point de référence limite (Blim) nécessiterait une pression de pêche à la morue et aux sébastes non durable pour réduire la mortalité par prédation. Le maintien de la biomasse de morue au-dessus du Blim nécessiterait quant à lui une forte prédation et un risque élevé d’effondrement des stocks de crevette et de sébastes. L’application de différentes RCP en deux volets réduirait la prédation, entraînant une productivité accrue et une plus faible probabilité d’effondrement de la morue et des sébastes. Les résultats de l’étude soulignent la nécessité de tenir compte des interactions d’espèces dans la conception de stratégies de gestion pour un groupe de stocks commerciaux interdépendants.

The International Bottom Trawl Survey Working Group (IBTSWG) coordinates fishery-inde-pendent multispecies bottom-trawl surveys within the ICES area. These long-term monitoring surveys provide data for stock assessments and facilitate examination of changes in fish distri-bution and abundance. The group also promotes the standardization of fishing gears and meth-ods and survey coordination. This report summarizes the national contributions in 2020–2021 and plans for the 2021–2022 surveys coordinated by IBTSWG. In the North Sea, the surveys are performed in quarters (Q) Q1 and Q3 while in the Northeast Atlantic the surveys are conducted in Q1, Q3, and Q4 with a suite of 14 national surveys covering a large area of continental shelf that ranges from North of Scotland to the Gulf of Cádiz. Despite the COVID-measures and bad weather, most surveys were able to complete the majority of the planned hauls. The Portuguese survey (PT-GFS-Q4) was cancelled in 2020 due to issues associated with the new vessel and a COVID-outbreak. A COVID-related delay in submitting the cruise application form for the French CGFS20 survey resulted in no authorisation to trawl in UK waters and only 70% of the core stations were completed. Issues with the UK permits, were also experienced in the North Sea surveys, only being resolved at the last moment, expected to be a returning issue. Therefore, IBTSWG addressed the permit issue in further detail in order to better evaluate the impact and propose possible solutions. All surveys, except for the Spanish GCGF-Q1 21 which is cancelled due to a vessel refit, are planned to take place according to the manuals in the next year. The SCOROC Q3 20 survey recorded second highest recruitment of zero group haddock on the Rockall Bank since the start of the new survey series in 2011. The North Sea Q1 21 survey rec-orded good recruitment of haddock as well, and high recruitment of mackerel, while overall herring recruitment seemed low except for three excepti

The main objective of the Working Group on Biological Parameters (WGBIOP) is to review the status, issues, developments, and quality assurance of biological parameters for use in assess-ments and management that are in line with the requirements of end-users. In this final year of the three-year term, WGBIOP operated under challenging circumstances due to COVID-19 measures. The initial action plan was replaced by a more flexible one, where online plenary and subgroup meetings were spread over the year with intersessional work to finalize the proposed deliverables. WGBIOP continued the review of past exchanges and workshops under the remit of the working group. Since 2019, these calibrations on age, maturity, and larvae identification have been carried out in SmartDots, an online platform for sharing images and facilitating the reading of otoliths, staging of gonads, and identification of early life stages. Developments are underway to include an improved calculation of modal age and error matrices in the SmartDots standard report. WGBIOP investigated ways to incorporate error matrices into assessments and studied the effect of this inclusion together with stock assessors. Requests for new exchanges and workshops were reviewed, with a focus on stocks to be bench-marked in the coming years. Issue lists were scrutinized, problems identified, and information provided to stock coordinators via regular channels and through the Stock Identification Data-base (SID). Despite close cooperation with stock assessors and continued efforts, it has not been possible to further streamline the WGBIOP workflow with the benchmark process. This will be addressed with the Advisory Committee. The need for validation studies was stressed by the repeated low levels of agreement between readers of some stocks and recurring issues and recommendations to WGBIOP. Lack of resources is the main obstacle. As a first step for measures to prioritize validation studies, WGBIOP iden-tified precision

El proyecto consiste en la creación de un brazo robótico controlado remotamente a través de un brazalete desarrollado por Thalmic Labs, el cual es capaz de leer los biopotenciales de los músculos residentes del muñón de los usuarios. Este proyecto, tiene como propósito la creación de una alternativa económica a las prótesis activas no invasivas que existen en la actualidad. Nuestra prótesis es capaz de realizar las mismas funciones, pero a un precio mucho más asequible. Para poder realizar todas las funciones que una articulación normal, el brazo cuenta con varios elementos: Cuerdas que simulan tendones y permiten el movimiento de los dedos, engranajes que permiten el giro de la muñeca y motores, los cuales son capaces de generar el movimiento en función de los datos extraídos del brazalete. El brazalete es el encargado de transmitir la información de la mano al brazo robótico a través de un módulo inalámbrico que lo conecta con el ordenador, donde la señal que extrae el brazalete pasa por un proceso de filtrado para quedarnos con la información que nos interesa y transmitirla mediante el puerto USB a un microcontrolador, el cual será el encargado de mover los motores según las señales que reciba. Para evitar errores en la medida de los sensores, la información recibida por el pc proveniente del brazalete pasa un proceso de entrenamiento mediante redes neuronales antes de ser enviada al brazo robótico., The project consists of the creation of a robotic arm controlled remotely through a brace developed by Thalmic Labs, which can read the biopotentials of the muscles of the limb of the users. This project aims to create an economic alternative to noninvasive active prostheses that exist today. Our prosthesis can perform the same functions but at a so much affordable price. To perform all the functions of a normal joint, the arm has several elements. Strings that simulate tendons and allow the movement of the fingers, gears that allow the rotation of the wrist and motors, which can generate movement based on the data extracted from the bracelet. The bracelet is responsible for transmitting information from the hand to the robotic arm through a wireless module that connects it with the computer, where the signal that extracts the bracelet goes through a filtering process to keep the information that interests us and Transmit it through the USB port to a microcontroller, which will be in charge of moving the engines according to the signals received. To avoid errors in the measurement of the sensors, the information received from the bracelet is trained in the computer using a Neural Network architecture before sending the information to the robotic arm.

El proyecto consiste en la creación de un brazo robótico controlado remotamente a través de un brazalete desarrollado por Thalmic Labs, el cual es capaz de leer los biopotenciales de los músculos residentes del muñón de los usuarios. Este proyecto, tiene como propósito la creación de una alternativa económica a las prótesis activas no invasivas que existen en la actualidad. Nuestra prótesis es capaz de realizar las mismas funciones, pero a un precio mucho más asequible. Para poder realizar todas las funciones que una articulación normal, el brazo cuenta con varios elementos: Cuerdas que simulan tendones y permiten el movimiento de los dedos, engranajes que permiten el giro de la muñeca y motores, los cuales son capaces de generar el movimiento en función de los datos extraídos del brazalete. El brazalete es el encargado de transmitir la información de la mano al brazo robótico a través de un módulo inalámbrico que lo conecta con el ordenador, donde la señal que extrae el brazalete pasa por un proceso de filtrado para quedarnos con la información que nos interesa y transmitirla mediante el puerto USB a un microcontrolador, el cual será el encargado de mover los motores según las señales que reciba. Para evitar errores en la medida de los sensores, la información recibida por el pc proveniente del brazalete pasa un proceso de entrenamiento mediante redes neuronales antes de ser enviada al brazo robótico., The project consists of the creation of a robotic arm controlled remotely through a brace developed by Thalmic Labs, which can read the biopotentials of the muscles of the limb of the users. This project aims to create an economic alternative to noninvasive active prostheses that exist today. Our prosthesis can perform the same functions but at a so much affordable price. To perform all the functions of a normal joint, the arm has several elements. Strings that simulate tendons and allow the movement of the fingers, gears that allow the rotation of the wrist and motors, which can generate movement based on the data extracted from the bracelet. The bracelet is responsible for transmitting information from the hand to the robotic arm through a wireless module that connects it with the computer, where the signal that extracts the bracelet goes through a filtering process to keep the information that interests us and Transmit it through the USB port to a microcontroller, which will be in charge of moving the engines according to the signals received. To avoid errors in the measurement of the sensors, the information received from the bracelet is trained in the computer using a Neural Network architecture before sending the information to the robotic arm.

El proyecto consiste en la creación de un brazo robótico controlado remotamente a través de un brazalete desarrollado por Thalmic Labs, el cual es capaz de leer los biopotenciales de los músculos residentes del muñón de los usuarios. Este proyecto, tiene como propósito la creación de una alternativa económica a las prótesis activas no invasivas que existen en la actualidad. Nuestra prótesis es capaz de realizar las mismas funciones, pero a un precio mucho más asequible. Para poder realizar todas las funciones que una articulación normal, el brazo cuenta con varios elementos: Cuerdas que simulan tendones y permiten el movimiento de los dedos, engranajes que permiten el giro de la muñeca y motores, los cuales son capaces de generar el movimiento en función de los datos extraídos del brazalete. El brazalete es el encargado de transmitir la información de la mano al brazo robótico a través de un módulo inalámbrico que lo conecta con el ordenador, donde la señal que extrae el brazalete pasa por un proceso de filtrado para quedarnos con la información que nos interesa y transmitirla mediante el puerto USB a un microcontrolador, el cual será el encargado de mover los motores según las señales que reciba. Para evitar errores en la medida de los sensores, la información recibida por el pc proveniente del brazalete pasa un proceso de entrenamiento mediante redes neuronales antes de ser enviada al brazo robótico., The project consists of the creation of a robotic arm controlled remotely through a brace developed by Thalmic Labs, which can read the biopotentials of the muscles of the limb of the users. This project aims to create an economic alternative to noninvasive active prostheses that exist today. Our prosthesis can perform the same functions but at a so much affordable price. To perform all the functions of a normal joint, the arm has several elements. Strings that simulate tendons and allow the movement of the fingers, gears that allow the rotation of the wrist and motors, which can generate movement based on the data extracted from the bracelet. The bracelet is responsible for transmitting information from the hand to the robotic arm through a wireless module that connects it with the computer, where the signal that extracts the bracelet goes through a filtering process to keep the information that interests us and Transmit it through the USB port to a microcontroller, which will be in charge of moving the engines according to the signals received. To avoid errors in the measurement of the sensors, the information received from the bracelet is trained in the computer using a Neural Network architecture before sending the information to the robotic arm.

This report summarizes fish community trends for the Flemish Cap (NAFO Div. 3M) based on European Union summer trawl research vessel surveys between 1988 and 2018. Species were classified into eight functional groups and trends were described using biomass indices, biomass and abundance anomalies, and fish size (Biomass/Abundance Ratio) anomalies. In 2003, a replacement of the research vessel allowed extending the depth coverage of the survey from 700m to 1400m. The vessel change had an impact on survey catchability, so to account for it conversion factors were applied. Considering the change in depth coverage, trends were examined for 1988-2018 with data up to 700m, and for 2004-2018 with data up to 1400m. Fish community trends were similar between the two datasets, but the analyses including deeper waters showed a comparatively higher levels of benthivores, reflecting the changes in community structure with depth. Generally speaking, trends in average fish size as tracked by the Biomass/Abundance Ratio appeared driven by recruitment, where general declines in abundance and absences of good recruitments got reflected in increases of this ratio. Biomass of plankpiscivores (mostly Sebastes sp.) experienced a sharp increase in the early 2000s but then returned to levels comparable to the 1990s. Piscivores biomass showed a strong decline in the early 1990s due to the collapse of cod but has since shown signs of recovery. Shellfish, driven by northern shrimp, saw a sustained increase in biomass from the early 1990s until 2002, when started a decline that has persisted until 2018. The biomass of large benthivores decline in the late 1990s and remains low to this date.

Multispecies modeling is being increasingly accepted in stock assessment, especially in the context of an ecosystem approach to fisheries management (EAF). To achieve a future implementation of an EAF in the Flemish Cap, we present a multispecies model developed in Gadget, which covers the main commercial stocks over the period 1988–2012: cod (Gadus morhua), redfish (Sebastes spp.), and northern shrimp (Pandalus borealis). The model highlights the interdependent dynamic of these stocks and reveals strong interactions among recruitment, fishing, and predation (including cannibalism). These drivers have shown marked changes in their relative importance by species, age, and length over time, producing a transition from a traditional redfish- and cod-dominated system in the early 1990s to an intermediate shrimp and other fish species state by the late 1990s and in turn back to something close to the initial state by the late 2000s. The multispecies model developed in this paper shows that disregarding the species interactions would lead to serious underestimates of natural mortality and overestimations of the exploitable biomass and highlights the need to move beyond single-species management in this highly coupled ecosystem

Since late 1980s, the demersal community of Flemish Cap (NAFO area 3M) has experienced large variations (including the collapse) in the abundance and population structure of its main fishing resources: cod Gadus morhua, redfish Sebastes sp. and shrimp Pandalus borealis, with alternation in their dominant role in the ecosystem. GadCap is an EU project dealing with the development of a GADGET multispecies model for the Flemish Cap cod, redfish and shrimp, as part of the NAFO roadmap for the EAF. The effect of fishing, trophic interactions (including cannibalism) and water temperature in the dynamic of these three major fishing resources has been modeled. The results highlight the interdependent dynamic of these stocks, and reveals strong interactions between recruitment, fishing and predation (including cannibalism), with marked changes in their relative importance by species-age-length over time. The multispecies model shows that disregarding the species interactions would lead to serious underestimates of natural mortality, overestimations of the exploitable biomass, and highlights the need to move beyond single-species management in this highly coupled ecosystem. Preliminary estimates of total SSB and MSY, under different combinations of fishing mortality for all the three stocks, are also presented.

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. fasciatus) redfish catches. An Extended Survivor Analysis (Shepherd, 1999) was used with the same framework of previous assessments and with the tuning of the 1989-2012 EU survey. 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. The most likely hypothesis to justify this unexpected downward trend on stock size is an increase in natural mortality by cod predation. From the sensitive analysis, natural mortality at 0.4 was applied on ages 4-6 through 2006-2010, and extended to ages 7 plus on 2009 and 2010. It has been kept constant through all ages on 2011 and 2012, but with an overall decline to 0.125.This is the highest possible level of natural mortality giving assessment results in line with the recent survey trends and at the same time with key diagnostics very close to the best ones, obtained with the return on 2011-2012 to the “standard” redfish natural mortality of 0.1. A 2013-2009 retrospective XSA was also carried out, being this assessment very much in line with their immediate predecessors (2012-2011). Above average year classes coupled with low fishing mortalities allowed a rapid growth of biomass and abundance since 200

Fish are expected to respond to changing oceanographic temperature by altering their distribution. Off the coast of Newfoundland, Canada, there have been major changes in oceanographic temperature over the last several decades, with both record cold and record warm years being observed. Greenland halibut is an important flatfish species in the area, and is distributed in deep waters over a very wide geographic range. Thus, it might be buffered from temperature change in the overall area by reduced temperature variation at depth, and the diverse temperature conditions over its wide range. We examined intrapopulation variation in temperature and depth distribution, and the biological changes in relation to changes in available temperature. On the Flemish Cap, variation in available temperature was limited, and changes in depth were related to changing age composition and the differential depth distribution with age/size. In other areas there was a larger decline in available temperature, and associated with this, Greenland halibut moved to deeper waters and occupied warmer temperatures than they had previously. Concurrently, growth declined and condition increased. This study shows that shifts in distribution may not result in maintenance of homogeneous environmental conditions, and that resulting biological changes will be difficult to predict.

Fish are expected to respond to changing oceanographic temperature by altering their distribution. Off the coast of Newfoundland, Canada, there have been major changes in oceanographic temperature over the last several decades, with both record cold and record warm years being observed. Greenland halibut is an important flatfish species in the area, and is distributed in deep waters over a very wide geographic range. Thus, it might be buffered from temperature change in the overall area by reduced temperature variation at depth, and the diverse temperature conditions over its wide range. We examined intrapopulation variation in temperature and depth distribution, and the biological changes in relation to changes in available temperature. On the Flemish Cap, variation in available temperature was limited, and changes in depth were related to changing age composition and the differential depth distribution with age/size. In other areas there was a larger decline in available temperature, and associated with this, Greenland halibut moved to deeper waters and occupied warmer temperatures than they had previously. Concurrently, growth declined and condition increased. This study shows that shifts in distribution may not result in maintenance of homogeneous environmental conditions, and that resulting biological changes will be difficult to predict.

Across the period 1988-2008, the most abundant demersal species were cod, redfish, Northern shrimp and Greenland halibut accounting, as an average, for the 83.5% of total index of biomass every year. The analyses of biomass indices showed that the demersal community experienced notable variations across the period 1988-2008, due to changes in biomass of most of the 67 demersal populations studied. The Dynamic Factor Analysis (DFA) identified common trends in the trajectories of the 31 most abundant species in the demersal community. This suggests that the dynamics of the demersal species in the Flemish Cap are interconnected, and can be summarized by a few common patterns. The explanatory variables considered in the analyses appeared to be consistently important for the population biomass dynamic of these species. Water temperature, along with predation and fishing mortality were significant drivers of the Flemish Cap demersal community. The abundance of the less common demersal species was related with water temperature, with a transition in the species composition between cold and warm periods. Changes in the demersal community were globally registered in the diversity indexes and the Abundance Biomass Comparison (ABC) method, with notable variations in the relative location of biomass and abundance kdominance curves. The size based indicators showed marked declines in the size structure of the fish demersal community. Parallel to these changes in the demersal community, since 1993 important variations in feeding habits for the most important fish species were observed. First, strong variations in feeding habits with size were found in most fish species and hence, biological species were split into trophic species. These trophic species belonged to four different trophic guilds, the bentho-pelagic invertebrate feeders, the benthic invertebrate feeders, the pelagic invertebrate feeders and the piscivorous guild. Not only intra-guild but also inter-guild common tren, when establishing fishing quotas, i.e. a multispecies approach to fisheries management instead of a monospecific approach. On the other hand, variations in feeding habits with fish length highlight the necessity of considering the demographic structure of both prey and predators when including trophic interactions in management decisions. Contemporaneously with changes in abundance of the Flemish Cap cod, changes in reproduction, growth and condition were detected. The high fishing mortality registered in the late 1980’s and early 1990’s contributed very importantly to the observed decrease in cod biomass. A genetic change toward earlier age and smaller size at maturation was found already in the 1980’s but especially in the early 1990’s cohorts. The decrease in Female Spawning Stock Biomass (FSSB) as consequence of the steep decline of the population, in conjunction with the rejuvenation of the reproductive stock, led to the decrease in the Total Egg Production (TEP). The high correlation of TEP with the recruitment during this period supports that the decrease in the SRP was largely responsible of the recruitment failures since mid 1990’s. However, the low temperatures recorded between 1989 and 1997 may have also lead to unfavorable conditions for cod recruitment. Cod fishing still remained in the Flemish Cap until 1996, which in conjunction with the absence of good recruitments, was the final blow contributing to the collapse. Since then density-dependent processes led to an increase in condition and growth, favoring earlier maturation by phenotypic plasticity and a growing FSSB. Although not studied in this thesis, it is probable that during this period the higher fish condition would led to an increased relative fecundity, producing an increase in the TEP. In the absence of fishing pressure, a higher SRP together with improved feeding conditions and higher temperatures probably favored the good recruitment events observed since 2005 and the recovery of the stoc, The higher availability of shrimp and redfish preys produced an increase in the SRP of cod, which favored the recovery of the cod stock since 2005. The increasing predation of a growing cod stock produced the decline of the redfish stock since 2008, while the Northern shrimp stock decline was ascribed to the increasing predatory pressure from both cod and redfish in conjunction with a very high fishing pressure., This conceptual model developed to study the ecological functioning of the demersal community in Flemish Cap supposes an integrative approach that represents an important step away from the traditional view of single species management in Flemish Cap. This type of contributions constitutes major steps towards a new framework for fisheries management that incorporates theoretical background on the functioning of marine ecosystems. Achieving a sustainable fishery requires to focus on sustaining relationships between species, which includes fishery within complex evolving ecosystems. Fisheries management should maintain these relationships stable and robust within a resilient ecosystem.

En los últimos tiempos han aparecido cada vez más estudios que cuestionan la proporcionalidad entre SSB y reclutamiento y se ha probado que en muchos casos no es una medida adecuada del potencial reproductivo del stock (SRP) (Marshall et all, 1998, Trippel, 1999). El aspecto cuantitativo del SRP, la producción total de huevos del stock (TEP), viene determinado por factores individuales como la fecundidad, así como por factores colectivos como la relación de sexos, la longitud media y la proporción de hembras maduras

The relationship between stock size and recruitment is an essential element in the understanding of the productivity of a population. However, predicting the number of recruits produced by a population has proven to be a difficult challenge. This may in part be a result of poor estimation of reproductive potential (RP). We determined if including increased information on reproductive biology in indices of RP results in better predictions of recruitment. We investigated some of the conditions that lead to better (or worse) recruitment prediction when more biologically complex indices of RP are used. Data from four populations in the Northwest Atlantic were examined: southern Grand Bank (NAFO Division 3NO) cod (Gadus morhua), Flemish Cap (NAFO Division 3M) cod, Newfoundland (NAFO Division 3LNO) American plaice (Hippoglossoides platessoides), and Greenland halibut (Reinhardtius hippoglossoides) (NAFO Subarea 2 + Division 3KLMNO). Stock–recruit models paired with complex indices of RP gave a better estimate of recruitment in slightly more than half of the tests conducted. When there were larger trends in the reproductive biology (maturity at age, sex ratio and egg production), more complex indices of RP were more likely to provide a better estimate of recruitment., The relationship between stock size and recruitment is an essential element in the understanding of the productivity of a population. However, predicting the number of recruits produced by a population has proven to be a difficult challenge. This may in part be a result of poor estimation of reproductive potential (RP). We determined if including increased information on reproductive biology in indices of RP results in better predictions of recruitment. We investigated some of the conditions that lead to better (or worse) recruitment prediction when more biologically complex indices of RP are used. Data from four populations in the Northwest Atlantic were examined: southern Grand Bank (NAFO Division 3NO) cod (Gadus morhua), Flemish Cap (NAFO Division 3M) cod, Newfoundland (NAFO Division 3LNO) American plaice (Hippoglossoides platessoides), and Greenland halibut (Reinhardtius hippoglossoides) (NAFO Subarea 2 + Division 3KLMNO). Stock–recruit models paired with complex indices of RP gave a better estimate of recruitment in slightly more than half of the tests conducted. When there were larger trends in the reproductive biology (maturity at age, sex ratio and egg production), more complex indices of RP were more likely to provide a better estimate of recruitment.

In stock-recruitment relationships, spawning stock biomass (SSB) has traditionally been assumed to be equivalent to total egg production (TEP); however, in the last decade a number of studies have indicated the need to include more biological complexity in measures of reproductive potential and advocate the use of TEP instead of SSB. The relationship between fecundity and length is often used to estimate TEP. In that case, the equations used to estimate female spawning stock biomass (FSSB) and TEP only differ in the coefficients determining the fecundity and weight relationships with length. In the present paper, TEP and FSSB have been estimated for Flemish Cap cod (Gadus morhua) for the period from 1978 to 2008. Total egg production was calculated using six different fecundity-length relationships applied to the whole time series in each case. A greater difference between the allometric coefficient in the weight-length and fecundity-length relationships led to a lower correlation between FSSB and TEP. The TEP time series using higher fecundity allometric coefficients explained a greater proportion of recruitment variance. Despite this pattern, correlation between FSSB and TEP was always higher than 0.96. These results support the necessity of making annual estimates of potential fecundity and studying its relation not only to length but to other variables, such as fish condition, in order to really get an improvement of TEP over FSSB as a predictive variable in recruitment assessments.