A social–ecological study of stock structure and fleet dynamics in the Newfoundland herring fishery

2017 ◽  
Vol 75 (1) ◽  
pp. 257-269 ◽  
Author(s):  
Barbara Paterson ◽  
Barbara Neis ◽  
Robert L Stephenson
Keyword(s):  
Ecological Study ◽  
Social Dynamics ◽  
Clupea Harengus ◽  
Stock Structure ◽  
Atlantic Mackerel ◽  
Social Ecological ◽  
Fishing Strategies ◽  
Stock Assessments ◽  
Fleet Dynamics ◽  
Pelagic Fisheries

Abstract Successful management of small pelagic fisheries is critical in integrated ecosystem based approaches and requires understanding of how the ecological dynamics of pelagic stocks mesh with the economic and social dynamics of commercial fisheries and the larger systems within which they operate. Combining insights from stock assessments with those from local fishers, scientists, and managers, can help identify knowledge gaps that could jeopardize stock resilience. This article presents results from a social-ecological, mixed-methods study that combines insights from science and from interviews with fishermen, scientists, and managers of small pelagic fisheries in western Newfoundland, Canada (NAFO division 4R) and in NAFO division 4X. Different approaches to herring management are used in the two areas. In area 4R fishing for herring (Clupea harengus) is part of a complex multi-species, multi-gear fishery; most harvesters who target herring also target Atlantic mackerel (Scomber scombrus). Harvester interviews indicate herring in 4R, like herring in 4X and elsewhere, have substantial within-species stock structure, but that it is not well-documented in science and not well protected under the current management system. Further, fishing strategies in the competitive mackerel fishery in which the herring vessels are involved may contribute to the risk of over-fishing on some herring populations.

scholarly journals Does size matter? A bioeconomic perspective on optimal harvesting when price is size-dependent

2011 ◽  
Vol 68 (9) ◽  
pp. 1651-1659 ◽  
Author(s):  
Fabian Zimmermann ◽  
Mikko Heino ◽  
Stein Ivar Steinshamn
Keyword(s):  
Body Size ◽  
Clupea Harengus ◽  
Optimal Harvesting ◽  
Atlantic Mackerel ◽  
Size Dependent ◽  
Maximum Economic Yield ◽  
Bioeconomic Modelling ◽  
Optimal Harvest ◽  
Size Matter ◽  
Pelagic Fisheries

Body size is a key parameter influencing demographic characteristics of fish populations as well as market value of landed catch. Yet in bioeconomic modelling, body size is often an overlooked biological and economic parameter. Here we evaluate how size-dependent pricing influences optimal harvest strategies in a model parameterized for two pelagic fisheries, those targeting Atlantic herring ( Clupea harengus ) and Atlantic mackerel ( Scomber scombrus ), in Norway. In our model, positively size-dependent pricing clearly shifts optimal harvest strategies towards lower harvest rates and higher mean body size of caught fish. The results are relatively insensitive to biological (e.g., natural mortality) and economic details of the model (e.g., discount rate or demand function). These findings show that size-dependent pricing influences optimal harvest strategies aiming at maximum economic yield and, hence, requires more attention in resource economics and in fisheries management.

scholarly journals Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework

2013 ◽  
Vol 70 (4) ◽  
pp. 768-781 ◽  
Author(s):  
Paul Marchal ◽  
Youen Vermard
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Spatially Explicit ◽  
Catch Per Unit Effort ◽  
Modelling Framework ◽  
Control Rules ◽  
Bioeconomic Modelling ◽  
Stock Assessments ◽  
Fleet Dynamics

Abstract Marchal, P., and Vermard, Y. 2013. Evaluating deepwater fisheries management strategies using a mixed-fisheries and spatially explicit modelling framework. – ICES Journal of Marine Science, 70: 768–781. We have used in this study a spatially explicit bioeconomic modelling framework to evaluate management strategies, building in both data-rich and data-limited harvest control rules (HCRs), for a mix of deepwater fleets and species, on which information is variable. The main focus was on blue ling (Molva dypterygia). For that species, both data-rich and data-limited HCRs were tested, while catch per unit effort (CPUE) was used either to tune stock assessments, or to directly trigger management action. There were only limited differences between the performances of both HCRs when blue ling biomass was initialized at the current level, but blue ling recovered more quickly with the data-rich HCR when its initial biomass was severely depleted. Both types of HCR lead, on average, to a long-term recovery of both blue ling and saithe (Pollachius virens) stocks, and some increase in overall profit. However, that improvement is not sufficient to guarantee sustainable exploitation with a high probability. Blue ling CPUE did not always adequately reflect trends in biomass, which mainly resulted from fleet dynamics, possibly in combination with density-dependence. The stock dynamics of roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo) and deepwater sharks (Centrophorus squamosus and Centroscymnus coelolepis) were little affected by the type of HCR chosen to manage blue ling.

scholarly journals Evaluation of species distribution forecasts: a potential predictive tool for reducing incidental catch in pelagic fisheries

2017 ◽  
Vol 74 (11) ◽  
pp. 1717-1731 ◽  
Author(s):  
Sara M. Turner ◽  
Jonathan A. Hare ◽  
John P. Manderson ◽  
David E. Richardson ◽  
John J. Hoey
Keyword(s):  
Species Distribution ◽  
Species Distribution Models ◽  
Forecast Model ◽  
Clupea Harengus ◽  
Distribution Models ◽  
Predictive Tool ◽  
Atlantic Mackerel ◽  
Alosa Aestivalis ◽  
Incidental Catch ◽  
Oceanographic Conditions

Nontarget catch restrictions are becoming common in fisheries management. We test a potential tool for reducing nontargeted catch that combines species’ distribution models and ocean forecast models. We evaluated our approach for Atlantic herring (Clupea harengus), Atlantic mackerel (Scomber scombrus), alewife (Alosa pseudoharengus), and blueback herring (Alosa aestivalis). Catch of the latter two species is capped in commercial fisheries of the former two species. Ocean forecasts were derived from a data-assimilative ocean forecast model that predicts conditions 0–2 days into the future. Observed oceanographic conditions were derived from CTD casts and observed fish presence–absence was derived from fishery-independent bottom trawl collections. Species distribution models were used to predict presence–absence based on observed and forecasted oceanographic conditions, and predictions for both were very similar. Thus, most of the error in predicted distributions was generated by the species distribution models, not the oceanographic forecast model. Understanding how predictions based on forecasted conditions compare with predictions from observed conditions is key to developing an incidental catch forecast tool to help industry reduce nontarget catches.

Using habitat association models to predict Alewife and Blueback Herring marine distributions and overlap with Atlantic Herring and Atlantic Mackerel: can incidental catches be reduced?

2015 ◽  
Vol 73 (7) ◽  
pp. 1912-1924 ◽  
Author(s):  
Sara M. Turner ◽  
John P. Manderson ◽  
David E. Richardson ◽  
John J. Hoey ◽  
Jonathan A. Hare
Keyword(s):  
Environmental Gradients ◽  
Generalized Additive Models ◽  
Habitat Associations ◽  
Additive Models ◽  
Clupea Harengus ◽  
Atlantic Herring ◽  
Alosa Pseudoharengus ◽  
Atlantic Mackerel ◽  
Blueback Herring ◽  
River Herring

Abstract Concern over the impacts of incidental catches of Alewife, Alosa pseudoharengus and Blueback Herring, A. aestivalis (collectively managed as ‘river herring’) in the commercial Atlantic Herring (Clupea harengus) and Atlantic Mackerel (Scomber scombrus) fisheries has resulted in the recent implementation of river herring incidental catch limits. These incidental catches are highly variable in frequency and magnitude, and the environmental conditions associated with these catches are poorly understood. We used generalized additive models (GAMs) to describe habitat associations of Alewife, Blueback Herring, Atlantic Herring, and Atlantic Mackerel. Bottom temperature, bottom depth, bottom salinity, solar azimuth and elevation, and region of the Northeast U.S. continental shelf were all significant in the habitat models; GAMs explained 25.2, 16.9, 18.9, and 20.6% of the deviance observed for the presence/absence of Alewife, Blueback Herring, Atlantic Herring, and Atlantic Mackerel. A subset of the data was omitted from the model and the probability of presence was compared with observations; 66–77% of observations were correctly predicted. The individual probabilities of presence were used to quantify and evaluate the accuracy of modelled overlap of Alewife and Blueback Herring with Atlantic Herring (68–72% correct predictions) and Alewife and Blueback Herring with Atlantic Mackerel (57–69% correct predictions). Our findings indicate that environmental gradients influence the distributions and overlap of Alewife, Blueback Herring, Atlantic Herring, and Atlantic Mackerel, and with further testing and refinement these models could be developed into a tool to aid industry in reducing incidental catches of river herring.

Reproductive Strategies of Demersal and Pelagic Spawning Fish

1984 ◽  
Vol 41 (11) ◽  
pp. 1565-1569 ◽  
Author(s):  
T. C. Lambert ◽  
D. M. Ware
Keyword(s):  
Growth Rate ◽  
Reproductive Strategies ◽  
Larval Growth ◽  
Clupea Harengus ◽  
Time Interval ◽  
Bet Hedging ◽  
Atlantic Mackerel ◽  
Larval Growth Rate ◽  
Mouth Size ◽  
The Relationship

The spawning tactic of herring (Clupea harengus) wherein batches of eggs are deposited leading to a succession of larval cohorts is elaborated. We found the time interval between cohorts to be a function of larval growth rate as well as larval mouth size. In view of the relationship with growth rate we suggest a continuum of reproductive strategies with "bet hedging" by herring at one extreme and an "all at once" egg release by Atlantic mackerel (Scomber scombrus) at the other.

scholarly journals Taxonomies for structuring models for World–Earth systems analysis of the Anthropocene: subsystems, their interactions and social–ecological feedback loops

2021 ◽  
Vol 12 (4) ◽  
pp. 1115-1137
Author(s):  
Jonathan F. Donges ◽  
Wolfgang Lucht ◽  
Sarah E. Cornell ◽  
Jobst Heitzig ◽  
Wolfram Barfuss ◽  
...  
Keyword(s):  
Social Dynamics ◽  
Feedback Loops ◽  
System Modelling ◽  
Earth System ◽  
Diverse Range ◽  
System Models ◽  
Social Ecological ◽  
Earth Models ◽  
Earth System Models ◽  
Current Modelling

Abstract. In the Anthropocene, the social dynamics of human societies have become critical to understanding planetary-scale Earth system dynamics. The conceptual foundations of Earth system modelling have externalised social processes in ways that now hinder progress in understanding Earth resilience and informing governance of global environmental change. New approaches to global modelling of the human World are needed to address these challenges. The current modelling landscape is highly diverse and heterogeneous, ranging from purely biophysical Earth system models, to hybrid macro-economic integrated assessments models, to a plethora of models of socio-cultural dynamics. World–Earth models capable of simulating complex and entangled human–Earth system processes of the Anthropocene are currently not available. They will need to draw on and selectively integrate elements from the diverse range of fields and approaches; thus, future World–Earth modellers require a structured approach to identify, classify, select, combine and critique model components from multiple modelling traditions. Here, we develop taxonomies for ordering the multitude of societal and biophysical subsystems and their interactions. We suggest three taxa for modelled subsystems: (i) biophysical, where dynamics is usually represented by “natural laws” of physics, chemistry or ecology (i.e. the usual components of Earth system models); (ii) socio-cultural, dominated by processes of human behaviour, decision-making and collective social dynamics (e.g. politics, institutions, social networks and even science itself); and (iii) socio-metabolic, dealing with the material interactions of social and biophysical subsystems (e.g. human bodies, natural resources and agriculture). We show how higher-order taxonomies can be derived for classifying and describing the interactions between two or more subsystems. This then allows us to highlight the kinds of social–ecological feedback loops where new modelling efforts need to be directed. As an example, we apply the taxonomy to a stylised World–Earth system model that endogenises the socially transmitted choice of discount rates in a greenhouse gas emissions game to illustrate the effects of social–ecological feedback loops that are usually not considered in current modelling efforts. The proposed taxonomy can contribute to guiding the design and operational development of more comprehensive World–Earth models for understanding Earth resilience and charting sustainability transitions within planetary boundaries and other future trajectories in the Anthropocene.

Refugee children’s resilience: A qualitative social ecological study of life in a camp

2020 ◽  
Author(s):  
Nilüfer Kuru ◽  
Michael Ungar
Keyword(s):  
Thematic Analysis ◽  
Ecological Study ◽  
Developmental Outcomes ◽  
Refugee Camp ◽  
Structured Interviews ◽  
Personal Traits ◽  
Social Ecological ◽  
Physical Wellbeing ◽  
Values And Beliefs ◽  
Inductive Thematic Analysis

Abstract A social ecological theory of resilience shows that the process of resilience not only depends on an individual child’s personal traits but also on the capacity of the child’s environment to provide the resources required for the child to use these traits to achieve psychological and physical wellbeing in contexts of adversity. The aim of this study is to investigate how refugee mothers influence their children’s developmental outcomes despite exposure to the large number of risk factors they experience living in a refugee camp. Ten Syrian mothers of children aged 5–7-years-old participated in both semi-structured interviews and focus groups conducted while they were living in a refugee camp in Turkey. Using an inductive thematic analysis, findings show that participants found unconventional ways to build their children’s social capital, provide an education and maintain culturally grounded values and beliefs when facing with multiple distal and proximal challenges. These findings highlight the importance of understanding resilience as a psychosocial and interactive process occurring at multiple systemic levels (in this case, child, mother, and camp). Improving the functioning of larger systems may be an efficacious way of creating stable and nurturing environments for children to experience greater resilience.

scholarly journals Seabird diets as bioindicators of Atlantic herring recruitment and stock size: a new tool for ecosystem-based fisheries management

2018 ◽  
Vol 75 (8) ◽  
pp. 1215-1229 ◽  
Author(s):  
Lauren C. Scopel ◽  
Antony W. Diamond ◽  
Stephen W. Kress ◽  
Adrian R. Hards ◽  
Paula Shannon
Keyword(s):  
Fishery Management ◽  
Gulf Of Maine ◽  
Clupea Harengus ◽  
Data Series ◽  
Atlantic Herring ◽  
Stock Biomass ◽  
Stock Assessments ◽  
Spawning Stock ◽  
Fishery Data ◽  
Ecosystem Based Fisheries Management

Ecosystem-based fishery management requires understanding of relationships between exploited fish and their predators, such as seabirds. We used exploratory regression analyses to model relationships between Atlantic herring (Clupea harengus) in the diet of seabird chicks at nine nesting colonies in the Gulf of Maine and four types of fishery- and survey-derived herring data. We found several strong relationships, which suggests spatial structuring in herring stocks and likely patterns of herring movements before they recruit into the fishery. Some types of herring data seldom used in stock assessments — notably acoustic surveys, fixed-gear landings, and mass-at-age (i.e., weight-at-age) — correlated as strongly with seabird data as more commonly used series, such as mobile-gear landings and modeled spawning stock biomass. Seabird chick diets collected at specific locations thus offer a promising means to assess the size, distribution, and abundance of juvenile herring across a broad area prior to recruitment, which is a major source of uncertainty in fisheries. Common terns (Sterna hirundo) showed the most potential as a bioindicator, correlating well and showing consistent spatial patterns with 11 of 13 fishery data series.

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