Marc H. Taylor

Thünen Institute | vTI · Institute of Sea Fisheries

Surplus production models (SPMs) have a long history in fisheries ecology and are important for the assessment and management of marine species and stocks. However, the implementation, application, and usage of these models vary across regions and case studies. Good practice guidelines can streamline modelling workflows, inform the acceptance or re...

Technical interactions (multiple fleets fishing multiple species with various gears, as either target or bycatch), bycatch regulations through a landing obligation, and biological and economic effects of climate change, affecting fisheries yield and profits, provide a challenge for demersal mixed fisheries of the North Sea. A multi-stock, multi-fle...

There is an increasing need for marine spatial planning in the North Sea given the multiple uses with competing objectives. Plans to increase renewable energy production by establishing offshore wind farms (OWFs) are likely to coincide with existing and planned marine protected areas (MPAs), with obvious incompatibilities relating to conservation g...

Ocean biogeochemical provinces have historically been used to characterize regions of similar biogeography, allowing for large‐scale comparisons and the definition of possible management units. Recent studies have shown that ocean color (OC) may be used as a proxy for a range of physical and biological parameters, allowing for a more direct approac...

Marine organisms are subject to environmental variability on various temporal and spatial scales, which affect processes related to growth and mortality of different life stages. Marine scientists are often faced with the challenge of identifying environmental variables that best explain these processes, which, given the complexity of the interacti...

The EU project SEAwise endeavours to enhance existing multi-stock multi-species Management Strategy Evaluation (MSE) models so that they can be used to define and evaluate fisheries management strategies that address broad Ecosystem-Based Fisheries Management (EBFM) objectives, including in particular identifying Harvest Control Rules (HCRs) that a...

Fisheries overviews summarize fishing activities in ICES ecoregions, including describing which countries are catching what species, the various fishing methods being used, the distribution and intensity of fishing, the status of fished stocks, how stocks are managed, and what the impacts of fisheries on the ecosystem are. Fisheries overviews ar...

ICES Scientific Reports

Mixed fisheries occur when multiple species are caught together and harvested by multiple fleets. The biological and technical interactions in mixed fisheries distinguish them from single-species fisheries, which makes them challenging for their assessment and management. The present knowledge synthesis reviewed pertinent policy documents and acade...

The objective of WKFISHDISH2 was to develop a standardized and open-source way of routinely using trawl survey data to produce distribution maps which can be easily updated. To do so, workshop participants (i) reviewed models that can produce distribution maps from survey data in DATRAS and MEDITS formats, (ii) considered best practice guidance for...

ICES Scientific Report

The objective of WKFISHDISH2 was to develop a standardized and open-source way of routinely using trawl survey data to produce distribution maps which can be easily updated. To do so, workshop participants (i) reviewed models that can produce distribution maps from survey data in DATRAS and MEDITS formats, (ii) considered best practice guidance for...

The main objective of the workshop was to review the recommendations of WKREF1 and consider how these might feed into a new reference points framework and guidelines for ICES. There were a number of presentations on the wider issues of best practice for reference points, the Allee effect, density dependence and the WKIRISH approach. The starting po...

The ICES Workshop on ICES reference points (WKREF1) was tasked to provide a thorough review of the ICES reference points system as a basis to re-evaluate the process for estimating, updating and communicating reference points in the context of the ICES advice. As part of the preparation leading to WKREF1 a large database of the most recent assessm...

To effectively future-proof the management of the European Union fishing fleets we have explored a suite of case studies encompassing the northeast and tropical Atlantic, the Mediterranean, Baltic and Black Seas. This study shows that European Union (EU) fisheries are likely resilient to climate-driven short-term stresses, but may be negatively imp...

In this paper, a sustainability framework with a case application for UK’s Scottish fisheries has been developed which integrates aspects related to economic growth, social development, governance, biology, environment, and logistics. Scotland is the centre of UK’s commercial fishery sector however it faces challenges such as overexploitation, and...

In this paper, a sustainability framework with a case application for UK's Scottish fisheries has been developed which integrates aspects related to economic growth, social development, governance, biology, environment, and logistics. Scotland is the centre of UK's commercial fishery sector however it faces challenges such as overexploitation, and...

The correct prediction of the shape and strength of density dependence in productivity is key to predicting future stock development and providing the best possible long‐term fisheries management advice. Here, we identify unbiased estimators of the relationship between somatic growth, recruitment and density, and apply these to 80 stocks in the Nor...

The ICES Working Group on Mixed Fisheries Advice (WGMIXFISH-ADVICE) met remotely to produce mixed fisheries forecasts for the Bay of Biscay, Celtic Sea, Iberian Waters and North Sea. Mixed fisheries advice highlights the potential implications of single-stock (total allowable catch and effort) management on the catches of multiple stocks caught tog...

The ICES Working Group on Mixed Fisheries Methodology (WGMIXFISH-METHODS) met to progress work on the improvement and development of the mixed fisheries advice. In this report the group provides a summary of the work completed in 2021. Work continued on the full review and documentation of the mixed fisheries advice production process, including wo...

ICES Scientific Report

In the European Union (EU), the ecosystem approach to fisheries is implemented through several directives and polices, which are overarched by the Marine Strategy Framework Directive (MSFD). The MSFD requires the assessment of the environmental status of exploited fish and shellfish stocks, among others, to advise the EU Common Fisheries Policy (CF...

This workshop is the third in a series of workshops on guidelines for developing Management Strategy Evaluations (MSEs) within ICES, and was intended to explore some of the issues that arose out of workshops that actually developed MSEs for a range of ICES stocks since the second MSE guidelines workshop was held in early 2019. It is intended that r...

ICES Scientific Report

The ICES Working Group on Mixed Fisheries Advice (WGMIXFISH-ADVICE) chaired by Claire Moore, Ireland, met at ICES headquarters in Copenhagen, Denmark, 28 October–1 November 2019 to produce mixed fisheries forecasts for the North Sea, Celtic Sea, and Iberian waters. Mixed fisheries advice highlights the potential implications of single-stock (total...

One of the most applied tools to create ecosystem models to support management decisions in the light of ecosystem-based fisheries management is Ecopath with Ecosim (EwE). Recently, its spatial routine Ecospace has evolved due to the addition of the Habitat Foraging Capacity Model (HFCM), a spatial-temporal dynamic niche model to drive the foraging...

The Workshop on the Development of Quantitative Assessment Methodologies based on Life-history traits, exploitation characteristics, and other relevant parameters for data-limited stocks (WKLIFE) focuses on the provision of sound advice rules for data-limited stock (DLS) assess-ments that are within the ICES MSY framework. This ninth workshop was c...

Performance evaluation of data-limited, length-based methods is instrumental in determining and quantifying their accuracy under various scenarios and in providing guidance about model applicability and limitations. We conducted a simulation-estimation analysis to compare the performance of four length-based stock assessment methods: length-based T...

The ability of organisms to adapt their foraging behaviour to spatial variations in food availability and habitat quality is crucial to maximize energy intake and hence fitness. Under ideal conditions, habitat selection should result in a spatial distribution of individuals such that their fitness (energy reserves or condition) is roughly equal acr...

The ICES Working Group on Mixed Fisheries Methodology (WGMIXFISH-METHODS) annual meeting centred on the improvement of the mixed fisheries advice production process, through increasing quality, transparency and reproducibility. Two ecoregions (Celtic Sea and North Sea) have begun the move to the Transparent Assessment Framework (TAF). Gaps in docum...

Spatially resolved past and projected changes of the suitable thermal habitat of North Sea cod (Gadus morhua) under climate change. Previous studies have identified changes in habitat temperature as a major factor leading to the geographical displacement of North Sea cod in the last decades. However, the degree to which thermal suitability is prese...

The purpose of the meeting was to bring up to date the methodologies and technical specifications that should be incorporated in Management Strategy Evaluation (MSE) work in ICES. The workshop was tasked with reviewing recent methodological and practical MSE work conducted in ICES and around the world, as well as the guidelines provided by the 2013...

WKNSMSE (Workshop on North Sea stocks Management Strategy Evaluation) took place over two physical meetings (19-21 November 2018 and 26-28 February 2019, but at ICES HQ, Copenhagen) and several WebEx meetings, was chaired by José De Oliveira (UK) and included 30 participants from Denmark, Germany, Netherlands, Norway, Sweden, UK and the European Co...

Isla del Coco (Costa Rica) forms part of the five oceanic islands of the Eastern Tropical Pacific and is well known for its high biodiversity and great endemism. While several marine biological and oceanographical surveys have been conducted around the island over the past 35 years, an integrated, systematic view of the shallow water system is lack...

The determination of rates of body growth is the first step in many aquatic population studies and fisheries stock assessments. ELEFAN (Electronic LEngth Frequency ANalysis) is a widely used method to fit a growth curve to length-frequency distribution (LFD) data. However, up to now, it was not possible to assess its accuracy or the uncertainty inh...

In June 2018, ICES accepted a special request from the European Commission to develop mixed fisheries considerations. This report was primarily prepared using work by members of WGBFAS and WGMIXFISH, ACOM, experts at DTU-AQUA, Denmark, and the ICES secretariat. Work on furthering the mixed fisheries analysis in the fisheries overviews was completed...

The Workshop on the Development of Quantitative Assessment Methodologies based on Life-history traits, exploitation characteristics, and other relevant parameters for stocks in categories 3–6 (WKLIFE VIII), chaired by Carl O'Brien (UK) and Manuela Azevedo (Portugal) met in Lisbon, Portugal, 8–12 October 2018, to further develop methods for stock as...

The determination of rates of body growth is the first step in many aquatic population studies and fisheries stock assessments. ELEFAN (Electronic LEngth Frequency ANalysis) is a widely used method to fit a growth curve to length-frequency distribution (LFD) data. However, up to now, it was not possible to assess its accuracy or the uncertainty inh...

This chapter presents an overview of some of the main issues facing the development of aqua-and mariculture, and provides a framework for improving sustainability from socioeconomic and ecological perspectives. We review present global trends in productivity and the institutional and legal frameworks that may affect policy and trade in the coming y...

The South Pacific bay scallop Argopecten purpuratus represents a high-value species harvested along the Peruvian and Chilean coastline for more than 60 years. Following the strong El Niño event of 1983/84, both countries experienced a boom in scallop fisheries, but catches dropped as soon as environmental conditions normalized. Aquaculture producti...

Electronic length frequency analysis (ELEFAN) is a system of stock assessment methods using length-frequency (LFQ) data. One step is the estimation of growth from the progression of LFQ modes through time using the von Bertalanffy growth function (VBGF). The option to fit a seasonally oscillating VBGF (soVBGF) requires a more intensive search due t...

The R package TropFishR is a new analysis toolbox compiling single‐species stock assessment methods specifically designed for data‐limited fisheries analysis using length‐frequency data. It includes methods for (i) estimating biological stock characteristics such as growth and mortality parameters, (ii) exploring technical aspects of the fisheries...

Understanding of the processes affecting recruitment of commercially important fish species is one of the major challenges in fisheries science. Towards this aim, we investigated the relation between North Sea hydrography (temperature and salinity) and fish stock variables (recruitment, spawning stock biomass and pre-recruitment survival index) for...

Fish stock assessment methods and fisheries models based on the FAO Manual ”Introduction to tropical fish stock assessment” by P. Sparre and S.C. Venema <http://www.fao.org/docrep/W5449E/W5449E00.htm>. Focus is the analysis of length-frequency data and data poor fisheries.

Changes in the coral reef complex can affect predator-prey relationships, resource availability and niche utilisation in the associated fish community, which may be reflected in decreased stability of the functional traits present in a community. This is because particular traits may be favoured by a changing environment, or by habitat degradation....

Sensitivity analysis. Each index (A: FRic and B: RaoQ) was calculated for all combinations of 5 of 6 weighted traits. This was also combined with null models based on 999 iterations, calculating SES values as stated in the primary paper (Measuring observed and expected functional diversity). Means (+/-SE) included all sites and replicates. Value of...

Relationship (standard deviation, SD) in the unweighted standard effect size of FRic (SESFRic) and RaoQ (SESRaoQ) as a function of environmental covariates. These figures are provided as visual comparison with the weighted results (Fig 3). Similar trends in SESFRic can be seen between the weighted and weighted SDs with rugosity and distance, howeve...

AIC scores of competing GAMs assessing their relationship with FRic. (DOCX)

AIC scores of competing GLMs assessing their relationship with RaoQ. Models are presented based on increasing AIC score. R2 was calculated by subtracting the residual deviance from the null deviance and then diving by the null deviance. F1, F2, F3 correspond to the model’s factors (Factor). (DOCX)

Correlation coefficients among all environmental covariates used as predictors for the SD of SESFRic and SESRaoQ. A correlation coefficient of 0.8 was considered a strong relationship at which a covariate would be removed from the subsequent models. Colours represent sampling sites and correspond to Fig 1: red = SA, green = BL, yellow = BO, blue =...

Average number of functional groups, average species richness, and average abundance of individual fishes (± SE 250m-2) for each of the surveyed Spermonde islands. Sites are listed from left to right in order of increasing distance from Makassar. (DOCX)

CWM trait-environment relationships. The table lists significant results of linear regression of transect-level standard deviations around the mean for individual CWM traits against three environmental parameters (rugosity, coral cover and distance from mainland). (DOCX)

Ocean warming is a major threat for coral reefs causing widespread coral bleaching and mortality. Potential refugia are thus crucial for coral survival. Exposure to large-amplitude internal waves (LAIW) mitigated heat stress and ensured coral survival and recovery during and after an extreme heat anomaly. The physiological status of two common cora...

The Peruvian bay scallop Argopecten purpuratus is a key resource of the Peruvian diving fishery that has long been harvested along the Peruvian and Chilean coastline. In the last decade, Sechura Bay (North Peru) has developed into a hotspot for its cultivation, which represents an important socio-economic activity for the region. Scallops are culti...

Changes in life-history traits have been observed in many fish species over past decades. This led to the “fisheries-induced evolution” hypothesis proposing that fisheries may be causing genetic changes to populations through selective harvesting. Another hypothesis, which is not mutually exclusive, is that observed changes are due to phenotypic pl...

The study explores the impacts of varying gillnet mesh size and fishing level on yield per recruit (Y/R), escapement spawning stock (ESS) and mega-spawners (MS) of three widely distributed freshwater fishery target species. Y/R is maximised when the optimal length of capture (L cap) is above the size of maturity (L 50). However, the unimodal shape...

Over the past decade, Sechura Bay has become an important center for mariculture in Peru, where the Peruvian bay scallop (Argopecten purpuratus) is grown in bottom cultures. Currently, the business involves 5000 artisanal fishermen and yields an export value of more than 158 million US$ per year. However,intensity and area extent of cultivation act...

We evaluated the statistical models that best describe the selectivity of common fishing gears used in Lake Koka for four freshwater species widely distributed in Ethiopia and elsewhere: tilapia Oreochromis niloticus (L.), catfish Clarias gariepinus (B.), common carp Cyprinus carpio (L.), and barb Labeobarbus intermedius (R.). Sampling was conducte...