The MEDITS trawl survey specifications in an ecosystem approach to fishery management

The MEDITS programme started in 1994 in the Mediterranean with the cooperation among research institutes from four countries: France, Greece, Italy and Spain. Over the years, until the advent of the European framework for the collection and management of fisheries data (the Data Collection Framework, DCF), new partners from Slovenia, Croatia, Albania, Montenegro, Malta and Cyprus joined MEDITS. The FAO regional projects facilitated the cooperation with non-European countries. MEDITS applies a common sampling protocol and methodology for sample collection, data storage and data quality checks (RoME routines). For many years, MEDITS represented the most important data source supporting the evaluation of demersal resources by means of population and community indicators, assessment and simulation models based on fishery-independent data. With the consolidation of the DCF, MEDITS routinely provides abundance indices of target species for tuning stock assessment models of intermediate complexity. Over the years, the survey scope has broadened from the population of demersal species to their fish community and ecosystems, and it has faced new challenges, such as the identification of essential fish habitats, providing new scientific insights linked to the Marine Strategy Framework Directive (e.g. biodiversity, trophic webs, allochthonous species and marine macro-litter evaluations) and to the ecosystem approach to fishery and marine spatial planning.

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Seasonal movements and connectivity of an Atlantic cod (Gadus morhua) spawning component in the western Gulf of Maine

ICES Journal of Marine Science ◽

10.1093/icesjms/fsw190 ◽

2017 ◽

Vol 74 (6) ◽

pp. 1780-1796 ◽

Cited By ~ 14

Author(s):

Douglas R. Zemeckis ◽

Chang Liu ◽

Geoffrey W. Cowles ◽

Micah J. Dean ◽

William S. Hoffman ◽

...

Keyword(s):

Population Structure ◽

Data Storage ◽

Gadus Morhua ◽

Fishery Management ◽

Gulf Of Maine ◽

Atlantic Cod ◽

Stock Assessment ◽

Movement Patterns ◽

Seasonal Movements ◽

Spawning Sites

Abstract Movement patterns of marine fishes can have considerable impacts on their population dynamics. A thorough understanding of fish movements is therefore required for informing stock identification, stock assessment, and fishery management. This study investigated the seasonal movements and connectivity of a spring-spawning component of Atlantic cod (Gadus morhua) in the western Gulf of Maine. From 2010 through 2013, spawning cod were sampled within an inshore spawning closure and tagged with conventional tags (n = 2368), acoustic transmitters (n = 106), and archival data storage tags (n = 266). Acoustic receivers were deployed on three inshore spawning sites to test for connectivity among sites. Data from archival tags were used to describe seasonal habitat occupancy and movement patterns via geolocation to statistical areas. Tagging data indicated that cod were primarily residential in the western Gulf of Maine, moving inshore to spawn during the spring (April–July), followed by an offshore migration to their feeding grounds for summer and fall. Cod generally inhabited waters from 45 to 175 m, with the deep offshore basins (>150 m) serving as overwintering habitat. Occupied water temperatures ranged from 4.0 to 13.3 °C, with the coldest temperatures experienced from March through July and the warmest temperatures experienced from September through January. Results provided evidence of spawning site fidelity and connectivity among spawning sites, with some fish visiting multiple spawning sites within or between years. The movements observed during and after the spring-spawning season serve as important mechanisms influencing metapopulation dynamics in the Gulf of Maine region, including both fine- and broad-scale population structure. The improved understanding of cod movement patterns will assist fishery managers in developing management plans, including spawning protection measures, and help to address remaining uncertainties with respect to cod population structure in the Gulf of Maine and other regions.

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Correcting density-dependent effects in abundance estimates from bottom-trawl surveys

ICES Journal of Marine Science ◽

10.1093/icesjms/fst208 ◽

2014 ◽

Vol 71 (5) ◽

pp. 1107-1116 ◽

Cited By ~ 12

Author(s):

Stan Kotwicki ◽

James N. Ianelli ◽

André E. Punt

Keyword(s):

Stock Assessment ◽

Dead Zone ◽

Walleye Pollock ◽

Assessment Model ◽

Bottom Trawl ◽

Trawl Survey ◽

Negative Consequences ◽

Catch Per Unit Effort ◽

Density Dependent ◽

Index Of Abundance

Abstract Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the efficiency of the survey bottom trawl (BT) for some species can be density-dependent, which could affect the reliability of survey-derived indices of abundance. A function qe∼f(u), where qe is the BT efficiency and u the catch rate, was derived using experimentally derived acoustic dead-zone correction and BT efficiency parameters obtained from combining a subset of BT catch data with synchronously collected acoustic data from walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS). We found that qe decreased with increasing BT catches resulting in hyperstability of the index of abundance derived from BT survey. Density-dependent qe resulted in spatially and temporarily variable bias in survey cpue and biased population age structure derived from survey data. We used the relationship qe∼f(u) to correct the EBS trawl survey index of abundance for density-dependence. We also obtained a variance–covariance matrix for a new index that accounted for sampling variability and the uncertainty associated with the qe. We found that incorporating estimates of the new index of abundance changed outputs from the walleye pollock stock assessment model. Although changes were minor, we advocate incorporating estimates of density-dependent qe into the walleye pollock stock assessment as a precautionary measure that should be undertaken to avoid negative consequences of the density-dependent qe.

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Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries ◽

10.47886/9781934874004.ch8 ◽

2008 ◽

Keyword(s):

Stock Assessment ◽

Distribution Patterns ◽

Abundant Species ◽

Trawl Survey ◽

Bathymetric Range ◽

Main Species ◽

The World ◽

Species Specific ◽

Depth Ranges ◽

Preanal Length

Abstract.—The objective of this study is to describe the distribution patterns of abundance and biomass, on a geographic and bathymetric basis, of the main macrourid species of Mozambique waters. Catch data from a demersal trawl survey (MOZAMBIQUE 07) were analyzed. The survey covered the continental shelf and upper-middle slope from 17°00’S to 26°50’S and from 100–700 m depth. Fourteen macrourid species were collected from 200 m and deeper. The most abundant species and the highest in biomass were Coelorinchus braueri, C. trunovi, C. denticulatus, Ventrifossa nasuta, and Malacocephalus laevis. Only those five species were analyzed in detail. The occurrence and yields by geographic and bathymetric range of these main species seem to reveal the existence of some species-specific preference for determinate depth ranges and/or geographic areas. Preanal length-weight relationships were estimated for C. braueri, C. trunovi, and V. nasuta: a= 0.00071; 0.00020; 0.00080; b= 2.50; 2.80; 2.76 and r2= 0.93; 0.97; 0.78, respectively.

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Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries ◽

10.47886/9781934874004.ch24 ◽

2008 ◽

Keyword(s):

Continental Slope ◽

Ross Sea ◽

Stock Assessment ◽

Trawl Survey ◽

Factors Affecting ◽

Year Effect ◽

Macrourus Whitsoni ◽

Catch Rates ◽

Potential Methods ◽

Major Factors

Abstract.—An exploratory longline fishery for toothfish (Dissostichus spp.) in the Ross Sea, Antarctica has been carried out since 1997. The main bycatch species in this fishery is the grenadier, Macrourus whitsoni. No assessments have been carried out of the impact of the fishery on grenadiers, although they have life history characteristics that make them vulnerable to overexploitation. The aims of this research were two-fold; firstly, to characterize the bycatch fishery and to determine factors affecting bycatch rates; and secondly to examine potential methods of monitoring its abundance. A standardized CPUE analysis was used to determine factors affecting bycatch rates of grenadiers in the fishery. The analysis was based on fine-scale haul-by-haul data from all vessels in the fishery from 1999 to 2005. The major factors influencing grenadier bycatch were vessel, area, and depth. Catch rates of grenadiers were highest along the continental slope of the Ross Sea in depths from 600 to 1000 m, and there was an order of magnitude difference in grenadier catch rates between different vessels. Examination of vessel characteristics showed that catch rates of grenadiers were significantly lower with the Spanish line system than with the autoline system. There are several plausible reasons for this difference, including hook location with respect to the seabed, bait type, and differences in levels of reporting of bycatch between vessels. Various approaches to monitoring and assessing grenadiers in the Ross Sea fishery were explored. We conclude that the year effect from the standardized CPUE analysis is unlikely to be monitoring abundance but instead probably reflect changes in gear characteristics, fisher behavior, and targeting of effort. Trends in the length composition of the catch are confounded with depth, and are also of limited value at present. We consider that the best approach to obtaining abundance estimates for grenadiers in the Ross Sea would be to carry out a random bottom trawl survey of the continental slope.

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Opportunistically recorded acoustic data support Northeast Atlantic mackerel expansion theory

ICES Journal of Marine Science ◽

10.1093/icesjms/fsv243 ◽

2015 ◽

Vol 73 (4) ◽

pp. 1115-1126 ◽

Cited By ~ 11

Author(s):

Jeroen van der Kooij ◽

Sascha M.M. Fässler ◽

David Stephens ◽

Lisa Readdy ◽

Beth E. Scott ◽

...

Keyword(s):

North Sea ◽

Stock Assessment ◽

Detection Algorithm ◽

Trawl Survey ◽

Northeast Atlantic ◽

Acoustic Data ◽

The North ◽

The North Sea ◽

Northern North Sea ◽

Feeding Grounds

Abstract Fisheries independent monitoring of widely distributed pelagic fish species which conduct large seasonal migrations is logistically complex and expensive. One of the commercially most important examples of such a species in the Northeast Atlantic Ocean is mackerel for which up to recently only an international triennial egg survey contributed to the stock assessment. In this study, we explore whether fisheries acoustic data, recorded opportunistically during the English component of the North Sea International Bottom Trawl Survey, can contribute to an improved understanding of mackerel distribution and provide supplementary data to existing dedicated monitoring surveys. Using a previously published multifrequency acoustic mackerel detection algorithm, we extracted the distribution and abundance of schooling mackerel for the whole of the North Sea during August and September between 2007 and 2013. The spatio-temporal coverage of this unique dataset is of particular interest because it includes part of the unsurveyed summer mackerel feeding grounds in the northern North Sea. Recent increases in landings in Icelandic waters during this season suggested that changes have occurred in the mackerel feeding distribution. Thus far it is poorly understood whether these changes are due to a shift, i.e. mackerel moving away from their traditional feeding grounds in the northern North Sea and southern Norwegian Sea, or whether the species' distribution has expanded. We therefore explored whether acoustically derived biomass of schooling mackerel declined in the northern North Sea during the study period, which would suggest a shift in mackerel distribution rather than an expansion. The results of this study show that in the North Sea, schooling mackerel abundance has increased and that its distribution in this area has not changed over this period. Both of these findings provide, to our knowledge, the first evidence in support of the hypothesis that mackerel have expanded their distribution rather than moved away.

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Designing tools to evaluate fishery management strategies: can the scientific community deliver?

ICES Journal of Marine Science ◽

10.1093/icesjms/fsm109 ◽

2007 ◽

Vol 64 (6) ◽

pp. 1077-1084 ◽

Cited By ~ 13

Author(s):

Jon T. Schnute ◽

Mark N. Maunder ◽

James N. Ianelli

Keyword(s):

Programming Languages ◽

Scientific Community ◽

Fishery Management ◽

Stock Assessment ◽

Management Strategies ◽

Academic Disciplines ◽

Strategy Evaluation ◽

Management Procedures ◽

Human Skills ◽

Testing Management

Abstract Schnute, J. T., Maunder, M. N., and Ianelli, J. N. 2007. Designing tools to evaluate fishery management strategies: can the scientific community deliver? – ICES Journal of Marine Science, 64: 1077–1084. Techniques for quantitative fishery management have evolved rapidly during a period when computers, programming languages, and computational algorithms have also changed dramatically. Despite these advances, many stock assessment methods remain untested. A process of management strategy evaluation (MSE) could potentially rectify this problem, but it would require a framework in which to conduct systematic tests. We survey the tools currently used for stock assessments and discuss the development of new standards for testing management procedures. A successful project would depend on human skills scattered among various nations, organizations, and academic disciplines. Analogies from civil engineering illustrate the discipline and collaboration required for an effective outcome. If the world community of fishery scientists could design, build, and support such a project, it would revolutionize the theory, teaching, and practice of scientific fishery management.

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Non-linearity in stock–recruitment relationships of Atlantic cod: insights from a multi-model approach

ICES Journal of Marine Science ◽

10.1093/icesjms/fsz113 ◽

2019 ◽

Vol 77 (4) ◽

pp. 1492-1502 ◽

Cited By ~ 5

Author(s):

Camilla Sguotti ◽

Saskia A Otto ◽

Xochitl Cormon ◽

Karl M Werner ◽

Ethan Deyle ◽

...

Keyword(s):

Environmental Variables ◽

Gadus Morhua ◽

Fishery Management ◽

Atlantic Cod ◽

Stock Assessment ◽

Fish Stock ◽

Recovery Potential ◽

Stock Recruitment ◽

Model Approach ◽

Non Parametric

Abstract The stock–recruitment relationship is the basis of any stock prediction and thus fundamental for fishery management. Traditional parametric stock–recruitment models often poorly fit empirical data, nevertheless they are still the rule in fish stock assessment procedures. We here apply a multi-model approach to predict recruitment of 20 Atlantic cod (Gadus morhua) stocks as a function of adult biomass and environmental variables. We compare the traditional Ricker model with two non-parametric approaches: (i) the stochastic cusp model from catastrophe theory and (ii) multivariate simplex projections, based on attractor state-space reconstruction. We show that the performance of each model is contingent on the historical dynamics of individual stocks, and that stocks which experienced abrupt and state-dependent dynamics are best modelled using non-parametric approaches. These dynamics are pervasive in Western stocks highlighting a geographical distinction between cod stocks, which have implications for their recovery potential. Furthermore, the addition of environmental variables always improved the models’ predictive power indicating that they should be considered in stock assessment and management routines. Using our multi-model approach, we demonstrate that we should be more flexible when modelling recruitment and tailor our approaches to the dynamical properties of each individual stock.

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Movements of Atlantic halibut in the Gulf of Maine based on geolocation

ICES Journal of Marine Science ◽

10.1093/icesjms/fsz169 ◽

2019 ◽

Vol 76 (7) ◽

pp. 2020-2032 ◽

Cited By ~ 3

Author(s):

Chang Liu ◽

Crista Bank ◽

Michael Kersula ◽

Geoffrey W Cowles ◽

Douglas R Zemeckis ◽

...

Keyword(s):

Data Storage ◽

Gulf Of Maine ◽

Stock Assessment ◽

Movement Patterns ◽

Seasonal Migration ◽

Atlantic Halibut ◽

Stock Structure ◽

Long Distance ◽

Archival Tags ◽

Straight Line Distance

Abstract Atlantic halibut are a “Species of Concern” in US waters and little is known about their movements and stock structure. Recent stock assessments drew attention to the paucity of information for assessing and managing this stock. To investigate movement patterns and stock structure, halibut were tagged off Massachusetts and Maine within US waters of the Gulf of Maine region using pop-up satellite archival tags and data storage tags. A hidden Markov model (HMM) geolocation method previously developed for other groundfish species was adapted to estimate the movement tracks of the tagged halibut (n = 25) based on the tag-recorded depth and temperature. Total distance travelled based on geolocation ranged from 36 to 1701 km, whereas straight line distance between tagging and end locations ranged from 0.4 to 440.7 km. Estimated movement rates varied between 2.7 and 10 km day−1. Two tagged halibut made long-distance movements to putative spawning habitat in the Northeast Channel off Georges Bank. Thirteen (13) out of 25 geolocated individuals were estimated to have reached Canadian waters. Geolocation results revealed home range, return movement, and seasonal migration movement patterns exhibited by the tagged halibut. The HMM geolocation method could be a useful tool in providing information on halibut movements that can inform stock assessment and management decisions.

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Ecological Reference Points for Atlantic Menhaden Established Using an Ecosystem Model of Intermediate Complexity

Frontiers in Marine Science ◽

10.3389/fmars.2020.606417 ◽

2020 ◽

Vol 7 ◽

Author(s):

David Chagaris ◽

Katie Drew ◽

Amy Schueller ◽

Matt Cieri ◽

Joana Brito ◽

...

Keyword(s):

Striped Bass ◽

Fishery Management ◽

Stock Assessment ◽

Reference Points ◽

Atlantic Menhaden ◽

Assessment Model ◽

Total Allowable Catch ◽

Important Species ◽

Ecosystem Impacts ◽

Intermediate Complexity

Atlantic menhaden (Brevoortia tyrannus) are an important forage fish for many predators, and they also support the largest commercial fishery by weight on the U.S. East Coast. Menhaden management has been working toward ecological reference points (ERPs) that account for menhaden’s role in the ecosystem. The goal of this work was to develop menhaden ERPs using ecosystem models. An existing Ecopath with Ecosim model of the Northwest Atlantic Continental Shelf (NWACS) was reduced in complexity from 61 to 17 species/functional groups. The new NWACS model of intermediate complexity for ecosystems (NWACS-MICE) serves to link the dynamics of menhaden with key managed predators. Striped bass (Morone saxatilis) were determined to be most sensitive to menhaden harvest and therefore served as an indicator of ecosystem impacts. ERPs were based on the tradeoff relationship between the equilibrium biomass of striped bass and menhaden fishing mortality (F). The ERPs were defined as the menhaden F rates that maintain striped bass at their biomass target and threshold when striped bass are fished at their Ftarget, and all other modeled species were fished at status quo levels. These correspond to an ERP Ftarget of 0.19 and an ERP Fthreshold of 0.57, which are lower than the single species reference points by 30–40%, but higher than current (2017) menhaden F. The ERPs were then fed back into the age-structured stock assessment model projections to provide information on total allowable catch. The ERPs developed in this study were adopted by the Atlantic menhaden Management Board, marking a shift toward ecosystem-based fishery management for this economically and ecologically important species.

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The sea pens Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis: distribution and conservation issues in Scottish waters

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315407056238 ◽

2007 ◽

Vol 87 (5) ◽

pp. 1095-1103 ◽

Cited By ~ 16

Author(s):

Clare F. Greathead ◽

David W. Donnan ◽

James M. Mair ◽

Graham R. Saunders

Keyword(s):

Stock Assessment ◽

Action Plan ◽

Ecosystem Approach ◽

Geographical Information ◽

Video Footage ◽

Commercial Species ◽

The Uk ◽

Video Surveys ◽

Marine Laboratory ◽

Future Management

The distributions of the pennatulid anthozoans (sea pens) Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis in Scottish waters have previously only been extensively documented in sea lochs, by the Marine Nature Conservation Review (MNCR) surveys. Funiculina quadrangularis in particular was thought to be restricted to the deep basins of sea lochs and is classified as a nationally uncommon species. Sea pens are characterizing species in seven biotopes found in Scottish waters and are protected under the ‘Mud in Deep Water Habitat Action Plan’ of the UK Biodiversity Action Plan (UKBAP) and are also recorded in several Special Areas of Conservation. The present study has extended the existing information available on sea pens in Scottish waters. The distribution and abundance of the three sea pen species were mapped using GIS (Geographical Information System) by utilizing data from Nephrops norvegicus stock assessment video surveys carried out by Fisheries Research Services (FRS) Marine Laboratory. Distribution was shown to be aggregated for all species. Funiculina quadrangularis was present in areas outside the sea lochs, such as the South Minch and the outer mouths of most sea lochs. This study demonstrates that analysis of video footage derived from Nephrops stock assessment surveys can significantly extend our knowledge of sea pen distribution and population density. Future management of Nephrops stocks can be expected to consider impacts of fishing on non-commercial species such as sea pens as a part of the ‘ecosystem approach’ to management.

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