Showing papers in "Fish and Fisheries in 2012"

Examining the knowledge base and status of commercially exploited marine species with the RAM Legacy Stock Assessment Database

Abstract: Meta-analyses of stock assessments can provide novel insight into marine population dynamics and the status of fished species, but the world’s main stock assessment database (the Myers Stock-Recruitment Database) is now outdated. To facilitate new analyses, we developed a new database, the RAM Legacy Stock Assessment Database, for commercially exploited marine fishes and invertebrates. Time series of total biomass, spawner biomass, recruits, fishing mortality and catch/landings form the core of the database. Assessments were assembled from 21 national and international management agencies for a total of 331 stocks (295 fish stocks representing 46 families and 36 invertebrate stocks representing 12 families), including nine of the world’s 10 largest fisheries. Stock assessments were available from 27 large marine ecosystems, the Caspian Sea and four High Seas regions, and include the Atlantic, Pacific, Indian, Arctic and Antarctic Oceans. Most assessments came from the USA, Europe, Canada, New Zealand and Australia. Assessed marine stocks represent a small proportion of harvested fish taxa (16%), and an even smaller proportion of marine fish biodiversity (1%), but provide high-quality data for intensively studied stocks. The database provides new insight into the status of exploited populations: 58% of stocks with reference points (n = 214) were estimated to be below the biomass resulting in maximum sustainable yield (BMSY) and 30% had exploitation levels above the exploitation rate resulting in maximum sustainable yield (UMSY). We anticipate that the database will facilitate new research in population dynamics and fishery management, and we encourage further data contributions from stock assessment scientists.

A quantitative assessment of fish passage efficiency

Abstract: In an attempt to restore the connectivity of fragmented river habitats, a variety of passage facilities have been installed at river barriers. Despite the cost of building these structures, there has been no quantitative evaluation of their overall success at restoring fish passage. We reviewed articles from 1960 to 2011, extracted data from 65 papers on fish passage efficiency, size and species of fish, and fishway characteristics to determine the best predictors of fishway efficiency. Because data were scarce for fishes other than salmonids (order Salmoniformes), we combined data for all non-salmonids for our analysis. On average, downstream passage efficiency was 68.5%, slightly higher than upstream passage efficiency of 41.7%, and neither differed across the geographical regions of study. Salmonids were more successful than non-salmonids in passing upstream (61.7 vs. 21.1%) and downstream (74.6 vs. 39.6%) through fish passage facilities. Passage efficiency differed significantly between types of fishways; pool and weir, pool and slot and natural fishways had the highest efficiencies, whereas Denil and fish locks/elevators had the lowest. Upstream passage efficiency decreased significantly with fishway slope, but increased with fishway length, and water velocity. An information-theoretic analysis indicated that the best predictors of fish passage efficiency were order of fish (i.e. salmonids > non-salmonids), type of fishway and length of fishway. Overall, the low efficiency of passage facilities indicated that most need to be improved to sufficiently mitigate habitat fragmentation for the complete fish community across a range of environmental conditions.

The fishery for Antarctic krill – recent developments

Abstract: The fishery for Antarctic krill (Euphausia superba) is the largest by tonnage in the Southern Ocean. The catch remained relatively stable at around 120 000 tonnes for 17 years until 2009, but has recently increased to more than 200 000 tonnes. The Commission for the Conservation of Antarctic Marine Living Resources precautionary catch limits for this species total over 8.6 million tonnes so it remains one of the ocean’s largest known underexploited stocks. Recent developments in harvesting technology and in products being derived from krill indicate renewed interest in exploiting this resource. At the same time, there are changes in the Southern Ocean environment that are affecting both krill and the fishery. This paper summarizes the current state of this fishery and highlights the changes that are affecting it.

Foraging arena theory

Abstract: There is a critical need for quantitative models that can help evaluate trade-off decisions related to the impacts of harvesting and protection of aquatic ecosystems within an ecosystem context. Ecosystem models used to evaluate such trade-offs need to have the capability of capturing the dynamic stability that can arise when predator-prey interactions are restricted to spatial and temporal arenas. Foraging arenas appear common in aquatic systems and are created by a wide range of mechanisms, ranging from restrictions of predator distributions in response to predation risk caused by their own predators, to risk-sensitive foraging behaviour by their prey. Foraging arenas partition the prey in each predator-prey interaction in a food web into vulnerable and invulnerable states, with exchange between these states potentially limiting overall trophic flow. Inclusion of vulnerability exchange processes in models for recruitment processes and food web responses to disturbances like harvesting leads to very different predictions about dynamic stability, trophic cascades and maintenance of ecological diversity than do models based on large-scale mass action (random mixing) interactions between prey and predators. Although a number of methods to estimate these critical exchange rates are presented, none are considered fully satisfactory. The most important challenge for the practical application of models that incorporate foraging arena theory today is not only developing new or improved methods for measuring exchange rates but also evaluating how such rates vary in responses to major fishery-induced changes in abundances of predators.

Rights-based fisheries governance: from fishing rights to human rights

Abstract: In the last twenty years, policy prescriptions for addressing the global crisis in fisheries have centred on strengthening fisheries governance through clarifying exclusive individual or community rights of access to fishery resources. With a focus on small-scale developing-country fisheries in particular, we argue that basing the case for fishery governance reform on assumed economic incentives for resource stewardship is insufficient when there are other sources of insecurity in people’s lives that are unrelated to the state of fishery resources. We argue that more secure, less vulnerable fishers make more effective and motivated fishery managers in the context of participatory or rights-based fisheries governance, and we further suggest that insecurity among fishers living in poverty can be most effectively addressed by social and political development that invokes the existing legal framework supporting the Universal Declaration of Human Rights. This perspective goes well beyond the widely advocated notion of ‘rights-based fishing’ and aligns what fishery sector analysts call the ‘rights-based approach’ with the same terminology used in the context of international development. Embedding the fisheries governance challenge within a broader perspective of human rights enhances the chances of achieving both human development and resource sustainability outcomes in small-scale fisheries of developing countries.

Implementing ecosystem-based management: evolution or revolution?

Abstract: As a dominant paradigm, ecosystem-based fisheries have to come to terms with uncertainty and complexity, an interdisciplinary visioning of management objectives, and putting humans back into the ecosystem. The goal of this article is to suggest that implementing ecosystem-based management (EBM) has to be ‘revolutionary’ in the sense of going beyond conventional practices. It would require the use of multiple disciplines and multiple objectives, dealing with technically unresolvable management problems of complex adaptive systems and expanding scope from management to governance. Developing the governance toolbox would require expanding into new kinds of interaction unforeseen by the mid-twentieth-century fathers of fishery science – governance that may involve cooperative, multilevel management, partnerships, social learning and knowledge co-production. In addition to incorporating relatively well-known resilience, adaptive management and co-management approaches, taking EBM to the next stage may include some of the following: conceptualizing EBM as a ‘wicked problem’; conceptualizing fisheries as social-ecological systems; picking and choosing from an assortment of new governance approaches; and finding creative ways to handle complexity.

Theories and behavioural drivers underlying fleet dynamics models

Abstract: In the domain of decision-support tools for the management of marine fish resources, considerable attention has been paid to the development of models explaining how fish stocks change over space and time. In most models, fishing effort is assumed to be exogenous and determined by factors such as management. Increasingly, there has been a call for bio-economic models to also account for the dynamics of fishing fleets, recognizing that fishers respond to changing environmental, institutional and economic conditions. A growing literature has sought to explicitly model the endogenous determinants of the capacity of fishing fleets, the intensity of its use and its temporal and spatial allocation across fishing opportunities. We review this literature, focusing on empirical applications of the behavioural models that have been put forward to explain and predict observed fleet dynamics. We find that although economic factors are usually included as a dominant driver in most studies, this is often based on the use of proxy variables for the key economic drivers, for which adequate data are lacking. Also, while many studies acknowledge that social and social–psychological factors play a significant role in explaining observed fishing behaviour, their inclusion in fishing fleet dynamic models is still very limited. Progress in this domain can only be achieved via the development of multidisciplinary research programmes focusing on applied quantitative analysis of the drivers of fishing fleet dynamics.

Contributions of food web modelling to the ecosystem approach to marine resource management in the Mediterranean Sea

Abstract: Ecological modelling tools are applied worldwide to support the ecosystem-based approach of marine resources (EAM). In the last decades, numerous applications were attempted in the Mediterranean Sea, mainly using the Ecopath with Ecosim (EwE) tool. These models were used to analyse a variety of complex environmental problems. Many applications analysed the ecosystem impacts of fishing and assessed management options. Other studies dealt with the accumulation of pollution through the food web, the impact of aquaculture or the ecosystem effects of climate change. They contributed to the scientific aspects of an ecosystem-based approach in the region because they integrated human activities within an ecosystem context and evaluated their impact on the marine food web, including environmental factors. These studies also gathered a significant amount of information at an ecosystem level. Thus, in the second part of this review, we used this information to quantify structural and functional traits of Mediterranean marine ecosystems at regional scales as the illustration of further potentialities of EwE for an EAM. Results highlighted differential traits between ecosystem types and a few between basins, which illustrate the environmental heterogeneity of the Mediterranean Sea. Moreover, our analysis evidenced the importance of top predators and small pelagic fish in Mediterranean ecosystems, in addition to the structural role of benthos and plankton organisms. The impact of fishing was high and of a similar intensity in the western, central and eastern regions and showed differences between ecosystem types. The keystone role of species was more prominent in protected environments.

Qualitative and quantitative effects of reintroduced beavers on stream fish

Abstract: Reintroduction of beaver (Castor spp) may facilitate rehabilitation of freshwater habitats providing a cost-effective sustainable means of improving ecological conditions. Despite extensive research, debate and consultation, a general consensus on the impact of beaver on fishes has proven elusive because of variability in biological response. This paper provides a systematic review of the impacts of beaver dams on fishes and fish habitat based on a meta-analysis of the literature and expert opinion. Research is regionally biased to North America (88%). The most frequently cited benefits of beaver dams were increased habitat heterogeneity, rearing and overwintering habitat and flow refuge, and invertebrate production. Impeded fish movement because of dams, siltation of spawning habitat and low oxygen levels in ponds were the most often cited negative impacts. Benefits (184) were cited more frequently than costs (119). Impacts were spatially and temporally variable and differed with species. The majority of 49 North American and European experts considered beaver to have an overall positive impact on fish populations, through their influence on abundance and productivity. Perceived negative effects related to the movement of aquatic organisms in tributary streams, including upstream and downstream migrating salmonids, and the availability of suitable spawning habitat.

Social behaviour in sharks and rays: analysis, patterns and implications for conservation

Abstract: There are widespread records of grouping behaviour in both adult and juvenile sharks and rays (Class Chondrichthyes, Subclass Elasmobranchii). Yet despite burgeoning descriptions of these events, many of the proximate and ultimate causes of group living in these top predators remain elusive. Given the documented negative anthropogenic effects on many shark populations globally, there is an increasing need to understand how behaviourally mediated grouping influences population distributions and abundance, and the role this plays in exacerbating vulnerability to fishing mortality. Here, we analyse group living in elasmobranchs: we describe our current understanding of the patterns, mechanisms and functions of both aggregation (where grouping is not driven by social mechanisms) and social grouping (where grouping is influenced by social interaction) and discuss some of the current methods used to study social behaviour in this taxa. In particular, social preferences in elasmobranchs have received relatively little attention. We propose that the study of shark aggregations may benefit from a more fine-scale analytical approach offered by detailed exploration of social interactions using social network analysis. Better understanding of the frequency and longevity of social relations, in conjunction with current long-term data on habitat use and site philopatry, will likely serve for a more informed approach to coastal and pelagic elasmobranch conservation initiatives.

Nutrition and income from molluscs today imply vulnerability to ocean acidification tomorrow

Abstract: Atmospheric carbon dioxide (CO2) emissions from human industrial activities are causing a progressive alteration of seawater chemistry, termed ocean acidification, which has decreased seawater pH and carbonate ion concentration markedly since the Industrial Revolution. Many marine organisms, like molluscs and corals, build hard shells and skeletons using carbonate ions, and they exhibit negative overall responses to ocean acidification. This adds to other chronic and acute environmental pressures and promotes shifts away from calcifier-rich communities. In this study, we examine the possible implications of ocean acidification on mollusc harvests worldwide by examining present production, consumption and export and by relating those data to present and future surface ocean chemistry forecast by a coupled climate-ocean model (Community Climate System 3.1; CCSM3). We identify the ‘transition decade’ when future ocean chemistry will distinctly differ from that of today (2010), and when mollusc harvest levels similar to those of the present cannot be guaranteed if present ocean chemistry is a significant determinant of today’s mollusc production. We assess nations’ vulnerability to ocean acidification-driven decreases in mollusc harvests by comparing nutritional and economic dependences on mollusc harvests, overall societal adaptability, and the amount of time until the transition decade. Projected transition decades for individual countries will occur 10‐ 50 years after 2010. Countries with low adaptability, high nutritional or economic dependence on molluscs, rapidly approaching transition decades or rapidly growing populations will therefore be most vulnerable to ocean acidification-driven mollusc harvest decreases. These transition decades suggest how soon nations should implement strategies, such as increased aquaculture of resilient species, to help maintain current per capita mollusc harvests.

The potential impacts of ocean acidification: scaling from physiology to fisheries*

Abstract: Views expressed on the potential impact of ocean acidification range from wholesale degradation of marine ecosystems through to no discernable impact with minimal consequences. Constraining this range of predictions is necessary for the development of informed policy and management. The direct biological impacts of acidification occur at the molecular and cellular level; however, it is the expression of these effects at the population and ecosystem level that is of societal concern. Here, we consider the potential impact of ocean acidification on fisheries with particular emphasis on approaches to scaling from physiological responses to population- and ecosystem-level processes. In some instances, impacts of ocean acidification may lead to changes in the relative species composition at a given trophic level without affecting the overall productivity, whilst in other instances, ocean acidification may lead to a reduction in productivity at a given tropic level. Because of the scale at which ecological processes operate, modelling studies are required. Here, ocean acidification is situated within ongoing research into the ecological dynamics of perturbed systems, for which many models have already been developed. Whilst few existing models currently explicitly represent physiological processes sensitive to ocean acidification, some examples of how ocean acidification effects may be emulated within existing models are discussed. Answering the question of how acidification may impact fisheries requires the integration of knowledge across disciplines; this contribution aims to facilitate the inclusion of higher trophic level ecology into this ongoing debate and discussion.

Environmental improvement of seafood through certification and ecolabelling: theory and analysis

Abstract: The study of environmental impacts of seafood production as a result of ecolabelling and certification is a young yet rapidly growing discipline that lacks theoretical models. Pieces of the model have been suggested in the literature, and these pieces are formalized here realizing the current operating parameters of the global seafood industry. The derived pull-threshold model assumes that if producers exceed the threshold, there is no incentive to improve while if too far below, improvement is most likely beyond technical or financial means. Thus, a single certification is only a marginal solution to the larger picture. Those producers immediately below the certification threshold are within range or ‘pull’ of the threshold to improve as a result of certification. Results from a single threshold model applied to compliance data indicated that a maximum improvement of 12.5%, achieved when the pull was the greatest and the threshold was at the lower end of the impact distribution. When impacts were continuous (e.g. escapes in aquaculture), greater improvement was observed with thresholds targeting the producers at the higher end of the impact distribution. In all cases, improvement was maximized with a triple threshold model, indicating that single threshold scenario will not drive the greatest movement towards environmental improvement throughout the industry. Innovation is potentially more important in reducing environmental impacts of seafood production and needs to be accounted for as the seafood certification or ecolabelling continues to mature.

Seafood mislabelling: comparisons of two western European case studies assist in defining influencing factors, mechanisms and motives

Abstract: The global seafood industry, influenced by consumer demand, is closely linked to the global fishing industry, which determines the variety of fish available for consumption. The recently revealed issue of seafood mislabelling threatens to weaken this link by removing consumer power to influence patterns of fisheries exploitation through informed choice. Recognizing this, there is an urgent need to go beyond the mere documentation of the phenomenon and learn more about the origins of this problem and the nature of factors influencing its occurrence to develop solutions. In an attempt to understand seafood mislabelling more thoroughly in Europe, 226 cod products were purchased from Ireland and the UK, genetically identified using a DNA barcoding technique (COI barcoding gene), and species identification results were compared against product labels. Cod mislabelling proved more severe in Ireland than in the UK (28.4% vs. 7.4%). Moreover, whereas data show that in Ireland, cheaper species are sold as cod, in the UK, threatened Atlantic cod (Gadus morhua) may be sold as ‘sustainably sourced’ Pacific cod. Considering these countries operate under the same EU policies for seafood traceability and labelling, it is likely that this situation has been influenced by heightened consumer awareness in the UK, which has created an environment where mislabelling is discouraged. In addition to identifying samples, traceability information from packaged cod was used to trace products back to supplying companies. Although inconclusive in determining blame, this exercise has demonstrated that using traceability information can add explanatory power when attempting to determine responsibility for the occurrence of mislabelling.

Can catch share fisheries better track management targets

Abstract: Fisheries management based on catch shares – divisions of annual fleet-wide quotas among individuals or groups – has been strongly supported for their economic benefits, but biological consequences have not been rigorously quantified. We used a global meta-analysis of 345 stocks to assess whether fisheries under catch shares were more likely to track management targets set for sustainable harvest than fisheries managed only by fleet-wide quota caps or effort controls. We examined three ratios: catch-to-quota, current exploitation rate to target exploitation rate and current biomass to target biomass. For each, we calculated the mean response, variation around the target and the frequency of undesirable outcomes with respect to these targets. Regional effects were stronger than any other explanatory variable we examined. After accounting for region, we found the effects of catch shares primarily on catch-to-quota ratios: these ratios were less variable over time than in other fisheries. Over-exploitation occurred in only 9% of stocks under catch shares compared to 13% of stocks under fleet-wide quota caps. Additionally, overexploitation occurred in 41% of stocks under effort controls, suggesting a substantial benefit of quota caps alone. In contrast, there was no evidence for a response in the biomass of exploited populations because of either fleet-wide quota caps or individual catch shares. Thus, for many fisheries, management controls improve under catch shares in terms of reduced variation in catch around quota targets, but ecological benefits in terms of increased biomass may not be realized by catch shares alone.

Antarctic silverfish: life strategies of a key species in the high-Antarctic ecosystem

Abstract: Among the endemic notothenioid fish of Antarctica, the Antarctic silverfish (Pleuragramma antarcticum) is the only species in which all developmental stages live throughout the water column. It is widely distributed in the shelf waters around the continent, inhabiting both open waters and areas of pack ice at depths from 0 to 900 m. In successfully occupying this habitat, it evolved a suite of specific biological, ecological and physiological adaptations to the environmental conditions in the cold and highly seasonal Antarctic waters. Specialization for the pelagic environment evolved over millions of years enabled life under unusual environmental constraints and colonization of the pelagic realm of the Antarctic continental shelf. A sudden change of environmental conditions driven by the current rapid climate change could negatively affect this weak equilibrium, with a catastrophic cascade effecting higher trophic levels. Indeed, as both adults and early life stages of the Antarctic silverfish appear to be strongly dependent on sea-ice, this species would be especially sensitive to climatic or oceanic changes that reduce the extent of sea-ice cover or the timing of formation of coastal polynyas.

Tool Use in Fishes

Abstract: Tool use was once considered the sole domain of humans. Over the last 40 years, however, it has become apparent that tool use may be widespread across the animal kingdom. Pioneering studies in primates have shaped the way we think about tool use in animals, but have also lead to a bias both in terms of our expectations about which animals should be capable of using tools and the working definition of tool use. Here I briefly examine tool use in terrestrial animals and consider the constraints of the current working definition of tool use in fishes. Fishes lack grasping limbs and operate underwater where there are clear constraints with respect to the physics of tool use that differ dramatically from the terrestrial environment. I then examine all of the documented accounts of tool use in fishes. The review reveals that tool use seems to be confined to a limited number of fish taxa, particularly the wrasse, which may show similarities with the greater than expected number of examples of tool use in primates and corvids amongst mammals and birds, respectively. As fish are seldom studied as intensely as birds and mammals, there is a clear need for further observation of tool use in fishes. It is likely that further examples will be unveiled allowing us to perform comparative analyses of the evolution of tool use in fish.

An exploration of the shapes and stability of population–selection curves

Abstract: Fishing operations on any given stock rarely generate fishing mortality that is uniform across all ages and sizes Population-selectivity refers to a scaled version of the age- or size-specific fishing mortality experienced by a fish population Although it is common to apply a sigmoid logistic curve for the selectivity produced by many kinds of fishing gear, the general characteristics of population–selection curves have not been well examined In this study, generalized additive models were fit to sets of selection coefficients taken from 15 recent stock assessments conducted using the virtual population analysis approach The selection coefficients predicted by the models provided smoothed representations of the shapes and temporal dynamics of selectivity Four broad types of selectivity were found: increasing, asymptotic, domed, and having a saddle Four specific cases, each dominated by one type of selection curve, were examined in detail For all 15 stocks, the population–selection curves were not stable through time but underwent changes in shape, which in some cases were quite radical Temporal variation in population-selectivity has important implications for the conduct of fisheries modelling activities such as evaluating management strategies and forecasting catch and stock size

Relative importance of habitat and fishing in influencing reef fish communities across seventeen Pacific Island Countries and Territories

Abstract: Reef fish assessments were undertaken in 17 Pacific islands to describe the status of finfish resources in 63 villages where fishing is mainly artisanal. Surveys were performed by recording the number and size of edible fish species and benthic composition. Fishing impact was described through six proxies representing level of catch, alternative incomes, degree of commercial catch and country economic development derived from a simultaneous socioeconomic assessment. The relative importance of broadly defined habitat (geographical location, island and reef type, substrate composition) and fishing impact in controlling the distribution of fish trophic groups, families and species was measured through multivariate analysis. The extreme faunistic diversity was shown by the large variation in fish density (difference of up to an order of magnitude) and fish biomass (displaying a 20-fold difference across the region). Herbivores were dominant in the eastern part of the region, at what we classified as complex islands and at islands with small lagoon and at coastal reefs, while carnivores were dominant at oceanic islands and atolls and at outer reefs. Specific habitat associations were shown for Scaridae, Acanthuridae, Siganidae, Balistidae, Lethrinidae, Lutjanidae and Serranidae. Relative importance and size decrease of several fish families (Mullidae, Scaridae, Lutjanidae and Serranidae) were related to high fishing impact. Acanthuridae and Lethrinidae appeared to have a role as opportunistic groups in impacted sites. The relative impact from fishing and habitat on fishes accounted for, respectively, 20 and 30% of variance, demonstrating the effect of human impacts even at such large scale and taking into account only limited fishing impact variables.

Assessing opportunity and relocation costs of marine protected areas using a behavioural model of longline fleet dynamics

Abstract: Increasing use of spatial management tools in fisheries requires an understanding of fleet response, and in particular to where displaced fishing effort is likely to move. We develop a state-dependent decision-making model to address the spatial allocation of effort in an Australian tuna longline fishery. We assume that fishers have an economic objective in deciding where to fish, but that decisions in any period are also influenced by the remaining quota held at the time of the decision. Key features of the model include endogenous price dynamics, a moving stock and a competitive pool of different vessel types operating from different port locations. We utilize this model to illustrate fleet responses to marine reserves and limits on fishing effort. The results illustrate that the model framework provides advantages over statistically based models in that decisions made in response to the imposition of a reserve are not consistent with a proportional reallocation of effort. Rather, the stochastic dynamic model yielded an overall profit level of � 4% higher relative to scenarios with no reserve. Incorporating the opportunity cost of a quota into the model resulted in an optimal utilization of effort, in which effort was concentrated in time periods and locations yielding maximized profit. Under a low level of effort relative to the season length, the model indicated an overall profit level 43% greater than the highest obtained when the same level of effort was applied solely within any given quarter of the season.

Empowerment and regulation – dilemmas in participatory fisheries science

Abstract: Using a perspective from the sociology of knowledge, this study identifies some ‘dilemmas of participatory research’ We look at how social relationships between fishers and scientists develop around the exchange of fishers’ knowledge in particular institutional contexts We survey the general types and global examples of fisher–scientist relationships in terms of how they approach the integration of fishers’ and scientists’ knowledge Based on an empirical study of three European cases of participatory research, we then discuss five dilemmas that tend to characterize fisher–scientist relationships These dilemmas centre on the relationship between fisheries research, fishery regulations and fishers as subjects of both regulation and participatory research endeavours We argue that these dilemmas – experienced by both scientists and fishers – express an underlying tension between ‘empowering’ fishers to support the effective management of the fishing commons and the bureaucratic need to regulate the fishery as an industry

Conservation of endemic landlocked salmonids in regulated rivers: a case‐study from Lake Vänern, Sweden

Abstract: Conservation of migratory salmonids requires understanding their ecology at multiple scales, combined with assessing anthropogenic impacts. We present a case-study from over 100 years of data for t ...

BMEY as a fisheries management target

Abstract: This paper evaluates the implications of managing fisheries to achieve a BMEY target, or a biomass level that maximizes net economic returns in the fishery, and discusses the role of private ownership and the trade-offs between economic and conservation benefits in this setting. The paper shows how a BMEY target can be used to: (i) determine relative employment and profitability measures; (ii) account for both the harvesting and processing sectors; and (iii) incorporate the interests of consumers and producers of fish. The profits‐employment trade-off of adopting a BMEY target vs. a traditional BMSY target is calculated using a model and data from the Western and Central Pacific tuna fisheries (WCPTF), while a generic bioeconomic model is constructed to show numerical values of BMEY from including processing and/or retail sectors and the consumer benefits of harvesting fish. For the WCPTF, results show that the long-term gains per job lost from pursuing a BMEY target are worth several times the value of the average GDP per capita of Pacific Island Countries. The generic bioeconomic model shows that including a processing and/or retail sector, as well as measures of consumer benefit, lowers the BMEY target. However, there remains a broad range of parameter values for which BMEY is still greater than biomass at maximum sustainable yield, or BMSY. The paper also illustrates cases where BMEY >B MSY at different values of the price elasticity of demand, margins for processing and/or retail sectors and values of the discount rate.

The Norwegian minke whale DNA register: a data base monitoring commercial harvest and trade of whale products

Abstract: The application of genetics for the management of natural resources is expanding, and within this field, DNA registers will play an increasing role. The Norwegian minke whale DNA register, established in 1996, was designed primarily as a control system to detect any attempts at illegal trade of products derived from other stocks of minke whale, or other whale species, under cover of the legal Norwegian harvest originating from the Northeast Atlantic. The register contains genetic data for 7644 of 7751 whales landed in the period 1997–2010. Profiles are established from sequencing part of the mtDNA control region, analysis of 10 STRs and a sex-determining marker. Probabilities of genotypes matching between two randomly selected whales are 6.0−04 and 3.0−08 for five and eight of the STR loci, respectively. This permits verification of traded whale products via match to the register. The register has also been used in a number of ad hoc scientific studies resulting through the accumulation of genetic, demographic and biological data. Here, we review the register’s logistics, specifications and evaluate the potential to apply similar registers to control the exploitation of other marine species.

Gasping Fish and Panting Squids: Oxygen, Temperature and the Growth of Water‐Breathing Animals

Abstract: Gasping Fish and Panting Squids: Oxygen, Temperature and the Growth of Water-Breathing Animals

Conservation status of eulachon in the California Current

Abstract: Eulachon (Thaleichthys pacificus), an anadromous smelt in the Northeast Pacific Ocean was examined for listing under the USA’s Endangered Species Act (ESA). A southern Distinct Population Segment (DPS) of eulachon – that occurs in the California Current and is composed of numerous subpopulations that spawn in rivers from northern California to northern British Columbia – was identified on the basis of ecological and environmental characteristics, and to a lesser extent, genetic and life history variation. Although the northern terrestrial boundary of this DPS remains uncertain, our consensus opinion was that this northern boundary occurs south of the Nass River and that the DPS was discrete from more northern eulachon, as well as significant to the biological species as a whole and thus is a ‘species’ under the ESA. Eulachon have been nearly absent in northern California for over two decades, have declined in the Fraser River by over 97% in the past 10 years, and are at historically low levels in other British Columbia rivers in the DPS, and nearly so in the Columbia River. Major threats to southern eulachon include climate change impacts on ocean and freshwater habitat, by-catch in offshore shrimp trawl fisheries, changes in downstream flow timing and intensity owing to dams and water diversions, and predation. These threats, together with large declines in abundance, indicate that the southern DPS of eulachon is at moderate risk of extinction throughout all of its range. The southern DPS was listed as threatened under the ESA in May 2010 – the first marine forage fish to be afforded these statutory protections, which apply only to waters under U.S. jurisdiction.

Beyond Individual Transferrable Quotas: methodologies for integrating ecosystem impacts of fishing into fisheries catch rights

Abstract: While there has been a growing concern for the adverse ecological impacts of fishing, progress on incorporating these into operational fisheries management has been slow. Many fisheries management organizations have addressed the problem of overharvesting and over-capitalization first. In this domain, the question of access regulation has gained growing recognition as a key dimension of fisheries sustainability, leading to recommendation and progressive implementation of rights-based systems, in particular Individual Transferrable Quotas (ITQs). While adjustments in fishing capacity resulting from the implementation of these systems may entail a reduction in some unwanted ecosystem impacts of fishing, it is also recognized that they will not be sufficient to achieve the ecological outcomes increasingly demanded by the global community. There is thus a need to examine the possibilities for a common management framework for dealing with both over-capitalization of fisheries and adverse ecological effects of fishing. In this paper, we examine the feasibility of incorporating greater ecosystem goods and services into ITQ policy instruments initially designed with a narrow focus on commercial target species. We consider the advantages and limitations of alternative approaches in this respect and identify some of the practical issues associated with the different alternatives, in particular the underpinning knowledge requirements. We argue that given the need for increasingly streamlined management processes, further investigation into practical ways forward in this domain is crucial if management of fisheries is to achieve economic efficiency while fully encompassing the ecologically sustainable development objectives of ecosystem-based fisheries management.