Search results for " marine"

The ability of fish ecolabels to promote a change in the sustainability awareness

2021

Abstract Researchers, environmentalists, as well as fisheries and retailers, have been focusing their attention on the design, use and effects that fish ecolabels have on sustainability. The fish processing industry and large retailers have rapidly adopted several market-based standards, with consequences for two major stakeholders: fishermen and consumers. Although the standards have shown rather positive results, from the perspectives of marine biodiversity conservation, the fish industry and trade, it is not clear how they are able to support a change in people’s awareness about sustainability. For this reason, the present work reviews and analyses the literature, produced in the last te…

Assessing multiple sources of data to detect illegal fishing, trade and mislabelling of elasmobranchs in Greek markets

2020

Abstract Elasmobranchs, extremely charismatic and threatened animals, still are an important economic source for fishers in many parts of the world, providing significant income through trade. Even though Greek seas host at least 67 elasmobranch species, our knowledge about their biology and ecology is to a large extent unknown. In the present study the integration of conventional (legislation, official data from fisheries landings and fish market value and import/export data) and unconventional (social media) sources of data, accompanied with the use of genetics, aim at outlining the elasmobranch fisheries and trade in Greece and identifying “weak spots” that sabotage their conservation. R…

Small-scale shrimp fisheries bycatch: a multi-criteria approach for data-poor situations

2020

Abstract Bycatch and discards from small-scale fisheries (SSF) are usually ignored when compared with industrial fisheries, not only by policy-makers, but also by scientists. Therefore, SSF social, economic and ecological impacts are poorly known and especially in the context of incidental catches, regardless of whether they become bycatch or discards. Such neglect is worrisome due to the role that SSF play in food security and poverty alleviation, particularly in coastal and rural communities in developing countries. In this study, a combination of sampling data and the fishers' behavior (specifically the basis of their decision on where to fish) were used. Bayesian models were applied to …

Impediments to fisheries recovery in Canada: Policy and institutional constraints on developing management practices compliant with the precautionary…

2020

The status of many Canadian fisheries is poor, a consequence of inadequate implementation of sustainable fishery policy within the context of the Precautionary Approach (PA). A key component of implementation lies with the provision of science advice. Scientists are responsible for advising on options likely to meet policy intent and objectives. Here, we examine PA-compliance in the role of science in Canada's fisheries management decision-making. We distinguish science-based from science-determined decisions and processes. Science-based decisions emerge from consultation processes involving stakeholders; science need not always have a clear and accountable role that can be transparently se…

Integrating fishing spatial patterns and strategies to improve high sea fisheries management

2018

Fishing activity in waters beyond national jurisdiction generates multiple management issues, such as data poor fisheries, management of straddling fish stocks and lack of impact assessments on deep-sea Vulnerable Marine Ecosystems (VMEs). Fishing strategy is the key to understanding and managing high seas fisheries, targeting highly migratory resources that are widely distributed. An international fleet, including Spanish flag bottom trawlers, operates along the Patagonian shelf in Southwest Atlantic waters, which includes an unregulated strip of continental shelf beyond national jurisdiction. The Spanish fleet’s fishing strategy was analyzed, and based on on-board observer data collected …

Eliciting expert knowledge to inform stock status for data-limited stock assessments

2019

Data-limited fisheries are a major challenge for stock assessment analysts, as many traditional data-rich models cannot be implemented. Approaches based on stock reduction analysis offer simple ways to handle low data availability, but are particularly sensitive to assumptions on relative stock status (i.e., current biomass compared to unperturbed biomass). For the vast majority of data-limited stocks, stock status is unmeasured. The present study presents a method to elicit expert knowledge to inform stock status and a novel, user-friendly on-line application for expert elicitation. Expert opinions are compared to stock status derived from data-rich models. Here, it is evaluated how expert…

2016

AbstractOcean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes. Here we show that ocean acidification increases energetic demands on gastropods resulting in altered energy allocation, i.e. reduced shell size but increased body mass. When scaled up to the population level, long-term exposure to ocean acidification altered population demography, with evidence of a reduction i…

Ecosystem processes are rarely included in tactical fisheries management

2015

Fish stock productivity, and thereby sensitivity to harvesting, depends on physical (e.g. ocean climate) and biological (e.g. prey availability, competition and predation) processes in the ecosystem. The combined impacts of such ecosystem processes and fisheries have lead to stock collapses across the world. While traditional fisheries management focuses on harvest rates and stock biomass, incorporating the impacts of such ecosystem processes are one of the main pillars of the ecosystem approach to fisheries management (EAFM). Although EAFM has been formally adopted widely since the 1990s, little is currently known to what extent ecosystem drivers of fish stock productivity are actually imp…

Examining nonstationarity in the recruitment dynamics of fishes using Bayesian change point analysis

2017

Marine ecosystems can undergo regime shifts, which result in nonstationarity in the dynamics of the fish populations inhabiting them. The assumption of time-invariant parameters in stock–recruitment models can lead to severe errors when forecasting renewal ability of stocks that experience shifts in their recruitment dynamics. We present a novel method for fitting stock–recruitment models using the Bayesian online change point detection algorithm, which is able to cope with sudden changes in the model parameters. We validate our method using simulations and apply it to empirical data of four demersal fishes in the southern Gulf of St. Lawrence. We show that all of the stocks have experience…

Multiple‐batch spawning as a bet‐hedging strategy in highly stochastic environments: An exploratory analysis of Atlantic cod

2021

Stochastic environments shape life‐history traits and can promote selection for risk‐spreading strategies, such as bet‐hedging. Although the strategy has often been hypothesised to exist for various species, empirical tests providing firm evidence have been rare, mainly due to the challenge in tracking fitness across generations. Here, we take a ‘proof of principle’ approach to explore whether the reproductive strategy of multiple‐batch spawning constitutes a bet‐hedging. We used Atlantic cod (Gadus morhua) as the study species and parameterised an eco‐evolutionary model, using empirical data on size‐related reproductive and survival traits. To evaluate the fitness benefits of multiple‐batc…