Conventional Fisheries Management Research Articles

Top-down and bottom-up control of plankton structure and dynamics in hypertrophic fishponds

We investigated the effects of strong top-down control by high fish stock on structure and seasonal dynamics of plankton in nine fishponds under conventional fishery management based on auxiliary feeding during two vegetation seasons. Mean concentrations of total nitrogen, phosphorus, and high densities of phytoplankton, bacteria, heterotrophic nanoflagellates, and ciliates indicated hypertrophic state of the fishponds, as well as a markedly reduced control of these microbial food web components by crustacean zooplankton. Mean seasonal densities of zooplankton varied within one order of magnitude for cladocerans, copepods, nauplii, and rotifers. Daphnia were found in most fishponds in densities up to 630 ind. l−1 (median: 53 ind. l−1). While TN and TP concentrations were high, dissolved inorganic N (median: 29 µg l−1) and reactive P (median: 11 µg l−1) indicated possible nutrient deficiency. The fish stock index (defined as the product of biomass and square root of densities) was used as a proxy for fish predation pressure. Multivariate analysis revealed that nutrients and high fish stocks (market carp, carp fry, and/or undesirable small planktivorous fishes) were the main driving forces shaping the fishpond plankton. The resulting trophic structure thus severely reduced the herbivorous zooplankton–fish link during a vegetation season.

Comparative assessment of the U.S. State of Florida’s Marine Life regulations for its commercial marine aquarium fish fishery

Governments in select locales around the world have recently either restricted or closed commercial marine aquarium fisheries, impacting the livelihoods of fishers, traders, and others who depend on them. This paper offers an objective assessment of Florida's commercial marine aquarium fish fishery and its regulatory landscape to inform and guide stakeholders about management strategies for the fishery moving forward, and to highlight successful regulations in place in Florida that merit consideration for adoption in other source locales around the world. The study discovered that the State has a strong regulatory structure for the commercial fishery operated by the Florida Fish and Wildlife Conservation Commission; practicing co-management with fishers, and utilizing license and permitting requirements, conventional fisheries management measures and technical actions to regulate fishing mortality, and rights-based management approaches. Additionally, both fisheries-independent and dependent surveys have been conducted in recent years to assess the fishery. Consequently, the vast majority of fish species collected commercially for the trade indicate stable or increasing catch trends in Florida waters over 10 + years. Moving forward, the fishery can benefit from an assessment of the economic impacts of the regulatory framework on its fishers, a statewide fisheries management plan specific for the fishery, the further development of a comprehensive program for fisheries data collection and analysis to address data gaps, an assessment of resources at hand and those needed to implement these recommendations, and the elevation of marine aquarium fisheries for support at the national level to support state-level management.

Harvester perceptions of climate vulnerability: Contributions to building climate resilient fisheries

The uncertainty of future ocean conditions caused by climate change challenges the conventional fisheries management model that assumes resource extraction occurs in a steady-state environment. As managers respond to climate impacts and focus on long-term preparedness, an overarching goal is to minimize the vulnerability of fishing businesses and communities. However, during the adaptation process, challenges can arise when perceptions of climate change vulnerability differ among scientists, managers, and harvesters. A harvester’s perception of their risk to climate change influences their willingness to plan for and respond to change, yet these views are often overlooked in adaptation planning. To better understand this dynamic, we conducted a regional survey to evaluate the perceptions harvesters hold regarding the impacts of climate change on commercially fished species in the Northeastern United States and the resulting risks from those changes. The waters in this region of the Northwest Atlantic shelf are warming faster than the global average resulting in shifting distributions of species, altered seasonal migrations, and changes in productivity. Respondents’ perceptions aligned with an analysis conducted by scientists on the directionality of climate impacts for 12 out of 27 (44%) of the most commercially important species in the region. Additionally, an understanding of the variability in perceptions of climate change vulnerability emerged: 72% of respondents believe climate change is occurring, 53% believe climate change will harm them personally, and 28% have already seen a negative impact on their ability to catch fish. Respondents who believe that climate change is occurring had higher perceptions of vulnerability on average than those who do not believe it is occurring. Despite a sense of vulnerability to climate change, respondents did not rank it among the top three concerns (fisheries regulations, market access, and access to working waterfronts) for their fishing businesses. Investigating harvester’s perceptions is an opportunity to share their experiences and understand the diversity of perspectives regarding the impacts of climate change. Increasing the inclusion of social science indicators and diverse perspectives will increase climate resilience of fisheries management.

Competing voices: Indigenous rights in the shadow of conventional fisheries management in the tropical rock lobster fishery in Torres Strait, Australia

Much progress has been made in recent decades in achieving high-level recognition of indigenous fishing rights. Despite these advances, actualization of indigenous rights to own and control marine resources has proven challenging. Insufficient attention to the centrality of power and its workings in fisheries are often the subject of critiques and of calls for more empirical research. This paper draws on interviews, participant observation, cognitive mapping, scenario workshops, and policy document review to examine power configurations and dynamics in the tropical rock lobster (TRL) fishery in Torres Strait (TS), Australia. Despite recognition of indigenous commercial fishing rights by the High Court in 2013, there have been only limited changes in how fisheries governance operates in the region. The current TRL management plan also risks entrenching non-indigenous interests in the fishery, thereby preventing Islanders from achieving their aspiration to fully own and control TS fisheries. Through an analysis drawing from Foucault’s theory of governmentality and Blaser’s political ontology framework, we show (1) how current fisheries management structures, processes and discourses are at odds with Islanders’ conceptions of the fisheries; and (2) how the existing regime excludes and renders silent Islander priorities. Our findings extend to indigenous-state relations in other state-managed fisheries. We believe our proposed conceptual framework can be useful in unveiling power relations that constrain indigenous rights and in identifying transformation options. We conclude that a sea change in conventional fisheries governance arrangements is needed to respond to new imperatives and expectations around indigenous fishing rights and interests.

Fishery harvest control rules from bioeconomic optimization

Harvest control rules (HCRs) are a central part of multiannual fisheries management plans as they are used to determine the appropriate catch levels based on current stock levels. Typically these HCRs are constructed using biological reference points, and although fisheries are inherently an economic activity, it is not common to use economic variables explicitly in the process. For this reason there is a need to know how a conventional HCR respond to changes in economic parameters, e.g. prices, costs or discount rates. This paper uses the method developed by Rosa et al. (2019) to construct HCRs from a bioeconomic optimization of an age-structured population, thereby bringing economics into conventional fishery management. The HCRs obtained therefore depend on both biological and economic parameters of the fishery. Sensitivity analysis is performed to illustrate this. The HCR is considerably sensitive to cost parameters, thus highlighting the need to consider economic assessments of fisheries parallel to the usual stock assessments.

Applying science to pressing conservation needs for penguins.

More than half of the world's 18 penguin species are declining. We, the Steering Committee of the International Union for Conservation of Nature Species Survival Commission Penguin Specialist Group, determined that the penguin species in most critical need of conservation action are African penguin (Spheniscus demersus), Galápagos penguin (Spheniscus mendiculus), and Yellow‐eyed penguin (Megadyptes antipodes). Due to small or rapidly declining populations, these species require immediate scientific collaboration and policy intervention. We also used a pairwise‐ranking approach to prioritize research and conservation needs for all penguins. Among the 12 cross‐taxa research areas we identified, we ranked quantifying population trends, estimating demographic rates, forecasting environmental patterns of change, and improving the knowledge of fisheries interactions as the highest priorities. The highest ranked conservation needs were to enhance marine spatial planning, improve stakeholder engagement, and develop disaster‐management and species‐specific action plans. We concurred that, to improve the translation of science into effective conservation for penguins, the scientific community and funding bodies must recognize the importance of and support long‐term research; research on and conservation of penguins must expand its focus to include the nonbreeding season and juvenile stage; marine reserves must be designed at ecologically appropriate spatial and temporal scales; and communication between scientists and decision makers must be improved with the help of individual scientists and interdisciplinary working groups.

Optimized fishing through periodically harvested closures

Abstract Periodically harvested closures are a widespread, centuries‐old form of fisheries management that protects fish between pulse harvests and can generate high harvest efficiency by reducing fish wariness of fishing gear. However, the ability for periodic closures to also support high fisheries yields and healthy marine ecosystems is uncertain, despite increased promotion of periodic closures for managing fisheries and conserving ecosystems in the Indo‐Pacific. We developed a bioeconomic fisheries model that considers changes in fish wariness, based on empirical field research, and quantified the extent to which periodic closures can simultaneously maximize harvest efficiency, fisheries yield and conservation of fish stocks. We found that periodic closures with a harvest schedule represented by closure for one to a few years between a single pulse harvest event can generate equivalent fisheries yield and stock abundance levels and greater harvest efficiency than achievable under conventional fisheries management with or without a permanent closure. Optimality of periodic closures at maximizing the triple objective of high harvest efficiency, high fisheries yield, and high stock abundance was robust to fish life history traits and to all but extreme levels of overfishing. With moderate overfishing, there emerged a trade‐off between periodic closures that maximized harvest efficiency and no‐take permanent closures that maximized yield; however, the gain in harvest efficiency outweighed the loss in yield for periodic closures when compared with permanent closures. Only with extreme overfishing, where fishing under nonspatial management would reduce the stock to ≤18% of its unfished level, was the harvest efficiency benefit too small for periodic closures to best meet the triple objective compared with permanent closures. Synthesis and applications. We show that periodically harvested closures can, in most cases, simultaneously maximize harvest efficiency, fisheries yield, and fish stock conservation beyond that achievable by no‐take permanent closures or nonspatial management. Our results also provide design guidance, indicating that short closure periods between pulse harvest events are most appropriate for well‐managed fisheries or areas with large periodic closures, whereas longer closure periods are more appropriate for small periodic closure areas and overfished systems.

Traditional Fisheries Management of Lake Bosomtwe, a Sacred Lake in Ghana: Past, Present and Future

Lake Bosomtwe is an ancient meteoritic impact crater lake, situated near Kumasi in the Ashanti Region of Ghana. The lake is highly prized as a major source of freshwater fish supply, livelihoods, and a resort attraction. The lake is held sacred because of the legend surrounding its discovery. Its predominantly cichlid fishery has been managed for many centuries only by laws that were shrouded in taboos or traditional religious prohibitions. Human activities with the tendency to upset the spirits believed to be dwelling in the lake, such as excessive agitation of the water, noise-making, fishing on a sacred day and the use of conventional nets were prohibited and outlawed. The chiefs, at the instance of the priests of the local shrines, demanded ritual (animal and drink) sacrifices from offenders in cases of non-observance of the taboos to pacify and avert the wrath of the spirits. Although, the laws were essentially traditional religious commandments they were not without connotations for conventional fisheries management. Currently, however, virtually all the traditional fisheries rules and regulations appear to have broken down, as modernity seems to have eroded their relevance, with the result that there is a serious overfishing and depletion of the fish stocks. Nevertheless, recovery of the dwindled fisheries is possible by blending conventional management practices and the traditional laws that are still deemed relevant.

Understanding bycatch using an EAF approach: The case of the Olifants estuary small-scale gillnet-fishery, South Africa

Conventional fisheries management approaches often prove ineffective in tackling issues such as bycatch, which require a more holistic approach, particularly in small-scale fisheries (SSF). Concerns about line-fish bycatch in the Olifants estuary gillnet fishery (OEGF), on the South African west coast, have prompted numerous attempts by government to close the small-scale fishery. Yet several other fisheries either target or include substantial bycatch of these same line-fish species. An EAF approach was utilised to examine the relative contributions of multiple fishing sectors on the status of three OEGF bycatch species: elf (Pomatomus saltatrix), silver kob (Argyrosomus inodorus) and white stumpnose (Rhabdosargus globiceps). Evidence from available data suggests that the catch and bycatch of these species associated with other fishing sectors, namely the commercial line- and inshore trawl-fishery, and recreational line-fishery, were orders of magnitude greater than the national beach-seine and gillnet fishery landings (inclusive of OEGF) for 2012 and of the OEGF bycatch in particular. Consequently, closing the OEGF, a primary source of food and livelihood to local resource-dependent fishers, would not necessarily address concerns about the stock status of these species. While estuarine function and life-history considerations are essential, employing an EAF to understand and address overall species exploitation levels across all fishing sectors will better resolve multiple-user conflicts and improve management practice.

The importance of qualitative social research for effective fisheries management

Over recent decades it has become widely accepted that managing fisheries resources means managing human behaviour, and so understanding social and economic dynamics is just as important as understanding species biology and ecology. Until recently, fisheries managers and researchers have struggled to develop effective methods and data for social and economic analysis that can integrate with the predominantly biological approaches to fisheries management. The field is now growing fast, however, and globally, researchers are developing and testing new methods. This paper uses three divergent case studies to demonstrate the value of using qualitative social science approaches to complement more conventional quantitative methods to improve the knowledge base for fisheries management. In all three cases, qualitative interview and document review methods enabled broad surveying to explore the research questions in particular contexts and identified where quantitative tools could be most usefully applied. In the first case (the contribution of commercial fisheries to coastal communities in eastern Australia), a wellbeing analysis identified the social benefits from particular fisheries, which can be used to identify the social impacts of different fisheries management policies. In the second case (a gender analysis of fisheries of small islands in the Pacific), analysis outlined opportunities and constraints along fisheries supply chains, illuminated factors inhibiting community development and identified ecological factors that are typically overlooked in conventional fisheries management. In the third case (sea cucumber fisheries in Papua New Guinea), an interactive governance analysis assessed how well fisheries management tools fit the ecological, social and economic reality of the fishery and the trade in its products, including market influences and stakeholder values. The qualitative approach adopted in these three case studies adds a new dimension to understanding fisheries that is not possible with a focus solely on quantitative data. With the development of new policies on release programs (stock enhancement, restocking) and artificial reefs, and the momentum to use these interventions from recreational fishing groups, the qualitative approach will provide an important contribution to understanding their wider costs and benefits.

Key aspects of the biology, fisheries and management of Coral grouper

Coral grouper (genus Plectropomus), or coral trout, are members of the grouper family (Epinephelidae) and are one of the largest and most conspicuous predatory fishes on Indo-Pacific coral reefs. They are highly-prized food fishes that are targeted by subsistence, artisanal, commercial and recreational fisheries throughout their geographic range. Plectropomus have broadly similar diets and habitat requirements to other tropical groupers, but typically have faster growth and higher natural mortality rates. Although these characteristics are expected to increase population turnover and reduce innate vulnerability to environmental and anthropogenic impacts relative to other groupers, many Plectropomus populations are in decline due to the combined effects of overfishing and habitat degradation. In many locations, stock depletion from uncontrolled fishing, particularly at spawning aggregation sites, has resulted in local fishery collapse. Therefore, improved management of wild populations is urgently required to ensure conservation and sustainable fisheries of Plectropomus. Where possible, a combination of no-take marine reserves, market-based management approaches, and allocation or resurrection of property rights systems are recommended to complement conventional fishery management actions that limit catch and effort. Additional investment in aquaculture propagation is also needed to reduce fishing pressure on wild stocks and support management initiatives. This global synthesis of information pertaining to the biology, fisheries and management of Plectropomus will assist in guiding future management actions that are attempting to address a range of stressors including fishing, reef habitat degradation, and the escalating effects of climate change.

Making Space for Community Use Rights: Insights From “Community Economies” in Newfoundland and Labrador

ABSTRACTCommunity use rights are rarely considered to be an economically viable or efficient option in conventional fisheries management policy. Our analysis challenges this view by pointing to the positive economic and social outcomes of community use rights in the Canadian province of Newfoundland and Labrador. We argue that resources allocated to community-based organizations can be used to build “community economies,” in the theoretical vocabulary of J. K. Gibson-Graham. By combining insights of Gibson-Graham’s diverse economies framework with an empirical analysis of how ethical decision making helped build and sustain community economies in three fishing regions, the article promotes the allocation of new community use rights in fisheries and beyond.

INITIATION ON ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT (EAFM): CASE STUDY ON TARAKAN FISHERIES

An EAFM from a global perspective is still moving towards on implementation. EAFM is based on conventional fisheries management but broadens the perspective beyond seeing a fishery as simply “fish in the sea, people in boats,” beyond consideration only of commercially important species, and beyond management efforts directed solely at the harvesting process. This research aims to initiate implementing EAFM in Indonesia: case in Tarakan Fisheries, North Kalimantan Province. From the initiate implementation of EAFM, we found that the possibility to improve the performance on arrange fisheries management based on ecosystem approach. EAFM could be used as tools to confirm scientific findings and gathering initial information on fisheries. In the case, fisheries community in Tarakan was put human well-being as important point to determine fisheries management, rather than ecological well-being. To secure the fisheries the possible options would arrange accepted and adaptable policy on controlling fisheries i.e. temporary fishing closure in term of area and season.

Applying empirical estimates of marine protected area effectiveness to assess conservation plans in British Columbia, Canada

While efforts to meet international commitments to counter biodiversity declines by establishing networks of marine protected areas (MPAs) continue, assessments of MPAs rarely take into account measures of effectiveness of different categories of protection, or other design principles (size, spacing, governance considerations). We carried out a meta-analysis of ecological effectiveness of IUCN Categories I–II (no-take), IV and VI (MPAs) compared to unprotected areas. We then applied our ecological effectiveness estimates – the added benefit of marine protection over and above conventional fisheries management – to a gap analysis of existing MPAs, and MPAs proposed by four indigenous groups on the Central Coast of British Columbia, Canada. Additionally, we assessed representation, size, spacing, and governance considerations against MPA design criteria outlined in the literature. We found significant differences in response ratios for IUCN Categories IV and VI MPAs compared to no-take reserves and areas open to fishing, although variability in responses was high. By rescaling the predicted ecological effectiveness ratios (including confidence estimates), we found that, compared to no-take reserves (biodiversity conservation effectiveness 100%) and open fishing areas (0% additional biodiversity contribution over and above conventional fisheries management), IUCN Category IV had a predicted effectiveness score of 60%, ranging between 34% and 89% (95% lower and upper confidence intervals, respectively), and IUCN Category VI had a predicted effectiveness score of 24% (ranging between −12% and 72% for the 95% lower and upper confidence intervals, respectively). We found that the existing MPAs did poorly when compared against most MPA design criteria, whereas the proposed MPA network achieved many of the best practices identified in the literature, and could achieve all if some additional sites were added. By using the Central Coast of British Columbia as a case study, we demonstrated a method for applying empirically-based ecological effectiveness estimates to an assessment of MPA design principles for an existing and proposed network of MPAs.

Viability trade-offs in the evaluation of strategies to manage recreational fishing in a marine park

Management strategy evaluation (MSE) is an analytical process used to evaluate alternative strategies for the management of renewable resource systems against explicitly stated objectives using a dynamic simulation framework. A key pre-requisite of MSE involves turning broad conceptual objectives into quantifiable and measurable operational objectives, against which the performance of management strategies can be assessed in simulations. However, given the large uncertainty typical of many renewable resource management problems and the potential diversity of stakeholder interests and needs, specification of operational management objectives for MSE often proves a challenge.In this article, a new approach to the evaluation of multidimensional outputs from MSE modeling, taking into account uncertainty regarding the reference levels of performance indicators (PIs) is proposed. The approach uses the notion of viable management strategies, as defined in recent applications of viable control to marine social-ecological systems, to examine the way in which simulated operational management objectives can be set. In this context, “viable” management strategies are defined as those which allow reference levels for candidate PIs to be met at some pre-agreed levels of tolerance, and we consider the possibility for these reference levels to be uncertain.The approach is applied to the multidimensional set of results from an MSE study conducted on recreational fishing for spangled emperor (Lethrinus nebulosus) in the Ningaloo Marine Park of Western Australia. The analysis shows how the complexities in management arrangements on recreational fishing, combining spatial management restrictions on fishing as well as conventional fisheries management regulations, which the MSE model accounted for in a multidimensional set of simulation results, can be synthesized using viability analysis. Results point to the existence of management options which provide greater “room to move”, in setting reference and tolerance levels, for the range of objectives identified by stakeholders. Beyond the application to Ningaloo Reef, the approach could be transferrable to any other simulation-based outcomes of MSE for natural resource systems, both marine and land-based.

Sustainable fishing of inland waters

Sustainability in fisheries has over the past decades evolved from a single species maximization concept to covering ecosystem and biodiversity considerations. This expansion of the notion, together with increased evidence that the targeted removal of selected components of the fish community may have adverse ecological consequences, poses a serious dilemma to the conventional fisheries management approach of protecting juveniles and targeting adults. Recently, the idea of balanced harvest, i.e., harvesting all components in the ecosystem in proportion to their productivity, has been promoted as a unifying solution in accordance with the ecosystem approach to fisheries, but this will require a fundamental change to management. In this paper, we review the objectives, theoretical background, and practicalities of securing high yielding fisheries in inland waters, with empirical examples from tropical freshwater fisheries which satisfy the extended objectives of minimal impact on community and ecosystem structure. We propose a framework of ecological indicators to assess these objectives.

Spatial management of Indian Ocean tropical tuna fisheries: potential and perspectives

Abstract Effective use of spatial management in the pelagic realm presents special challenges due to high fish and fisher mobility, limited knowledge and significant governance challenges. The tropical Indian Ocean provides an ideal case study for testing our ability to apply existing data sources to assessing impacts of spatial management on tuna fisheries because of several recent controversial spatial closures. We review the scientific underpinnings of pelagic MPA effects, spatio-temporal patterns of Indian Ocean tuna catch, bycatch and fish movements, and the consequences of these for the efficacy of spatial management for Indian Ocean tropical tuna fisheries. The tropical Indian Ocean is characterized by strong environmental fluctuations, regular seasonal variability in catch, large observed tuna displacement distances, relatively uniform catch-per-unit-effort and bycatch rates over space, and high fisher mobility, all of which suggest significant variability and movement in tropical tuna fisheries that are simply not well adapted to static spatial closures. One possible exception to this overall conclusion would be a large time/area closure east of Somalia. If closed for a significant fraction of the year it could reduce purse-seine bycatch and juvenile tuna catch. Dynamic closures following fish migratory patterns are possible, but more focused information on fish movements will be needed for effective implementation. Fortunately, several recent improvements in conventional fishery management and reporting will likely enhance our ability to evaluate spatial and non-spatial management options in the near future, particularly as pertaining to bycatch species.

Chapter Six - Marine Protected Area Networks in California, USA

California responded to concerns about overfishing in the 1990s by implementing a network of marine protected areas (MPAs) through two science-based decision-making processes. The first process focused on the Channel Islands, and the second addressed California's entire coastline, pursuant to the state's Marine Life Protection Act (MLPA). We review the interaction between science and policy in both processes, and lessons learned. For the Channel Islands, scientists controversially recommended setting aside 30-50% of coastline to protect marine ecosystems. For the MLPA, MPAs were intended to be ecologically connected in a network, so design guidelines included minimum size and maximum spacing of MPAs (based roughly on fish movement rates), an approach that also implicitly specified a minimum fraction of the coastline to be protected. As MPA science developed during the California processes, spatial population models were constructed to quantify how MPAs were affected by adult fish movement and larval dispersal, i.e., how population persistence within MPA networks depended on fishing outside the MPAs, and how fishery yields could either increase or decrease with MPA implementation, depending on fishery management. These newer quantitative methods added to, but did not supplant, the initial rule-of-thumb guidelines. In the future, similar spatial population models will allow more comprehensive evaluation of the integrated effects of MPAs and conventional fisheries management. By 2011, California had implemented 132 MPAs covering more than 15% of its coastline, and now stands on the threshold of the most challenging step in this effort: monitoring and adaptive management to ensure ecosystem sustainability.

BOFFFFs: on the importance of conserving old-growth age structure in fishery populations

AbstractThe value of big old fat fecund female fish (BOFFFFs) in fostering stock productivity and stability has long been underappreciated by conventional fisheries science and management, although Hjort (1914) indirectly alluded to the importance of maternal effects. Compared with smaller mature females, BOFFFFs in a broad variety of marine and freshwater teleosts produce far more and often larger eggs that may develop into larvae that grow faster and withstand starvation better. As (if not more) importantly, BOFFFFs in batch-spawning species tend to have earlier and longer spawning seasons and may spawn in different locations than smaller females. Such features indicate that BOFFFFs are major agents of bet-hedging strategies that help to ensure individual reproductive success in environments that vary tremendously in time and space. Even if all else were equal, BOFFFFs can outlive periods that are unfavourable for successful reproduction and be ready to spawn profusely and enhance recruitment when favourable conditions return (the storage effect). Fishing differentially removes BOFFFFs, typically resulting in severe truncation of the size and age structure of the population. In the worst cases, fishing mortality acts as a powerful selective agent that inhibits reversal of size and age truncation, even if fishing intensity is later reduced. Age truncation is now known to destabilize fished populations, increasing their susceptibility to collapse. Although some fisheries models are beginning to incorporate maternal and other old-growth effects, most continue to treat all spawning-stock biomass as identical: many small young females are assumed to contribute the same to stock productivity as an equivalent mass of BOFFFFs. A growing body of knowledge dictates that fisheries productivity and stability would be enhanced if management conserved old-growth age structure in fished stocks, be it by limiting exploitation rates, by implementing slot limits, or by establishing marine reserves, which are now known to seed surrounding fished areas via larval dispersal. Networks of marine reserves are likely to be the most effective means of ensuring that pockets of old-growth age structure survive throughout the geographic range of demersal species.

Holistic Fisheries Management: Combining Macroecology, Ecology, and Evolutionary Biology

Ecosystem-based management is one of many indispensable components of objective, holistic management of human impacts on nonhuman systems. By itself, however, ecosystem-based management carries the same risks we face with other forms of current management; holism requires more. Combining single-species and ecosystem approaches represents progress. However, it is now recognized that management also needs to be evosystem-based. In other words, management needs to account for all coevolutionary and evolutionary interactions among all species; otherwise we fall far short of holism. Fully holistic practices are quite distinct from the approaches to the management of fisheries that are applied today. In this paper, we show how macroecological patterns can guide management consistently, objectively, and holistically. We present one particular macroecological pattern with two applications. The first application is a case study of fisheries from the Baltic Sea involving historical data for two species; the second involves a sample of 44 species of primarily marine fish worldwide. In both cases we evaluate historical fishing rates and determine holistic/systemic sustainable single-species fishing rates to illustrate that conventional fisheries management leads to much more extensive and pervasive overfishing than currently realized; harvests are, on average, over twenty-fold too large to be fully sustainable. In general, our approach involves not only the sustainability of fisheries and related resources but also the sustainability of the ecosystems and evosystems in which they occur. Using macroecological patterns accomplishes four important goals: 1) Macroecology becomes one of the interdisciplinary components of management. 2) Sustainability becomes an option for harvests from populations of individual species, species groups, ecosystems, and the entire marine environment. 3) Policies and goals are reality-based, holistic, or fully systemic; they account for ecological as well as evolutionary factors and dynamics (including management itself). 4) Numerous management questions can be addressed.