Summing up Sendai: Progress Integrating Climate Change Science and Fisheries

The Sendai Conference promotes global stabilization and understanding of international waters and inter-related events by pointing out what needs to be improved upon and the successes we have witnessed thus far.  Overwhelming evidence was presented at the Sendai Conference of the instability of marine fisheries caused by climate-dependent factors, which include productivity, spatial distribution, phenology, and human dimensions.  Not all changes within these factors may be negative but they provide little certainty of how society will adapt. –Alyshia Silva
Murawski, S.A. 2011.  Summing up Sendai: Progress Integrating Climate Change Science and Fisheries.  ICES Journal of Marine Science 68, 1368–1372

          Control of overfishing has become a global priority to ensure food security, and the Sendai Conference placed a global focus on dealing with the issues, rather than specific regions, species, or other subsets within climate change.  Using meta-analyses is becoming a reality with coupled modeling, nesting atmosphere, land, ocean, and other biological components together, and methodologies and models are improving quickly.  Methods that bring together regional downscaling (atmospheric models linked to terrestrial and aquatic ecosystems) and upscaling (oceanographic models nested in atmospheric models) are a new development that can provide holistic data and ways to deal with it. 
          In particular with downscaling, there are no standardized methods and approaches do not exist.  Instead, different methodologies for projecting regional and local climates are used and more consistent frameworks are needed.  Most studies to date have operated on a species-by-species basis and the lack of species interactions is a clear flaw of these studies.  Integrating trophic dynamics through foodweb analyses and size-based methods must become incorporated into existing methodologies as a feasible path to sustainability.           There is also great bias towards certain areas where fisheries are examined, such as the North Atlantic, North Pacific, southern Africa, and a few other places globally.  We must identify other pertinent climate “hotspots” and focus our attention there as well, whether they be locations that are not well-studied or vulnerable locations that may not exhibit extreme temperature increases. 
          The effects of climate change become confounded by both additive and multiplicative factors and interactions, worsening issues of marine fisheries.  Holistic data through the sciences, social sciences, and policy must come together to understand the synergistic effects, and coupling multi-sectoral models are needed to understand ecosystem and community effects.  The issue itself branches across multiple disciplines and will affect all societies but in, perhaps, different ways considering that access to science and technology is not equal and significant latitudinal responses will occur, allowing certain places to adapt more readily than others. 
          It is also key to understand the direct role humans play within this system, especially because of the economic and regulatory environment fisheries are in.  Discussions at Sendai encouraged knowledge from all different types of people and places, therefore exploring diverse perceptions and increase communication among various societal groups.  With this information, we can perhaps explore the positive economic effects of other countries, considering that productivity will shift pole-wards. 
          There are also clear issues between fisheries and climate change specialists – fishery decision-makers are primarily focused on short-term goals while climate change specialists’ focus is upon long-term changes.  The time-scale solution lies in better communicating the climate-fishery impacts of actions to both parties.  The ecosystem approach, an integrated method, encourages society to deal with highly complex issues, especially in a global context.  

Food Security and Marine Capture Fisheries: Characteristics, Trends, Drivers, and Future Perspectives

In 2006, marine capture fisheries produce 82 million tons of fish a year and may have now reached up to 100 million tons, a possible upper limit.  An important source of protein, vitamins, and micronutrients, particularly for low-income populations in rural areas, fisheries, which include 32 million tons from inland aquaculture and 20 million tons from marine aquaculture, play a critical role in global food security.  While demand is high, marine populations are highly stressed by excessive fishing pressure, toxic contamination, pollution, costal degradation, and climate change.  How fisheries are governed and the success of related international and national policy will play a crucial role in ensuring that marine capture fisheries continue feeding the world.–Alyshia Silva
 
Garcia, S.M., Rosenberg, A.A., 2010. Food Security and Marine Capture Fisheries: Characteristics, Trends, Drivers, and Future Perspectives. Philosophical Transitions of the Royal Society 365, 2869–2880

          By 2050, the world’s population will reach 9 billion, mostly in the developing world (5.6–7.9 billion).  Fishery resources are an important part of the world’s daily diet, especially for low-income populations in developing countries.  At least 20% of fisheries are moderately exploited while 52% are fully exploited, 19% are overexploited, 8% are depleted, and 1% is recovering from previous depletion.  These numbers could lead to the permanent decline of fish populations, leaving the world to solve a significant new food deficit.  Other issues of marine capture fisheries include 11–26 million tons of illegal, unreported, and unregulated (IUU) fishing as well as 9.5 million tons of discarded unwanted catch.
          Destructive and IUU fishing can cause great environmental harm in itself, especially when resulting in marine debris from lost gear that continue to fish and entangle wildlife.  It greatly affects the food web and can alter the ecosystem function and structure while lessening productivity and resilience to other drivers such as climate change. 
          Fish overall are important as a means of food and livelihood, especially for the poor.  At least 1.5 billion people rely on fish as 20% of their average per capita intake of animal protein, the majority of these populations coming from low-income food deficit countries.  About 110 million tons of produced fish are used for food directly while 33 million tons are used as fishmeal.  Around 42 million people work directly in the fishing sector while related activities support at least 500 million livelihoods.  Overall, fisheries and aquaculture sector contribute about 0.5–2.5% of a country gross domestic product (GDP).  Poverty within these low-income countries may contribute to over fishing; however, healthy fisheries can contribute to poverty reduction through generation of revenues and wealth-creation. 
          World population is a key driver in fish demand, and with the rise in population and 70% of this population moving to cities, especially ones near coasts, and demand will rise with increased levels of development and living standards.  An increasingly globalized market will increase demand as well, and enhance competition.  The governance frameworks adopted at the national, regional, and global levels are intended interact in a “continuous but asynchronous manner (i.e. developing at different speeds in different places)”.  Weak governance, on the other hand, has become a major problem mostly due to incomplete jurisdictions and the lack of clear and defendable entitlements. 
          With increasing globalization comes a need to solve issues with an inter-disciplinary focus, dealing with economics, environment, and the human perspective.  Global climate change in itself will test not only humanity’s ability to reduce consumption and find environmentally sustainable means of fish production, but will test the ecosystem’s resilience and ability to adapt.  The ecosystem’s ability to produce fish, stability of supply, and access to food will be affected by global climate change, and methodologies incorporating both the social and hard sciences will be needed to adequately address these issues. 
          Although global food security might change minimally, local consequences will be drastic, particularly in poor coastal areas.  A reduction of harvesting capacity will result in consequences for both humans and the environment and we need to address key inter-connected global/local issues to smartly use our resources.  Without key governance building, fishery resources will drop.  We must look to maintain and optimize current production and profitability in terms of quality and quantity.  The fishing industry will need, with the help of government, to adapt its technology to changing resources and to support small fisheries that would otherwise create disenfranchised coastal communities.  Fisheries governance is a unique combination of public, private, and hybrid institutions and utilizing these administrators is crucial to creating a holistic, multi-disciplinary solution for both people and place.  

Uncertainties in Projecting Spatial Distributions of Marine Populations

An important issue for marine ecologists and managers is the projection of future spatial distributions of marine populations.  Projecting spatial distributions can be a useful but only if they are given with a known and sufficiently high level of confidence.  These uncertainties can arise for the observation process, conceptual and numerical model formulations, parameter estimates, model evaluation, appropriate spatial and temporal scales, and the adaptation of living systems.  To analyze different sources of uncertainty and the ways they are considered in current studies, 75 publications for 2005–2009 were selected and the frequency of considered type of uncertainty was calculated.  What was found was that there is little attention to many sources of uncertainty except for parameter estimates.  Unless certainty can be better accounted for, such projections may be of limited use for managerial purposes.–Alyshia Silva
  
Planque, B., Bellier E., Loots, C. 2011.  Uncertainties in Projecting Spatial Distributions of Marine Populations.  ICES Journal of Marine Science 68, 1045–1050. 

          Spatial distributions define the geographical extent of marine population, as well as the abundance of the individuals or density within these geographical boundaries.  Projecting spatial distributions for marine populations is becoming a more difficult task and a chief concern for managers, conservationists, and human communities that depend on marine resources.  In particular, measuring uncertainty is important because spatial distributions should only be useful if they are given with a high-level of confidence.  Major sources of uncertainty are related to the observation process, conceptual and numerical model formulations, parameter estimates, model evaluation, appropriate spatial and temporal scales, and the adaptation of living systems. 
          The observation process is the way we perceive the marine world, which is already a very limited methodology due to filtered observation instruments and a lack of a uniform method to observe adequately.  Our representation of this world is therefore inadequate and incomplete.  Conceptual model formulations are mental representations of the processes that control the spatial distribution of marine populations.  These models are becoming increasingly difficult to use because environmental conditions can no longer be compared to observable past climatological phenomenon.  Numerical implementations within a conceptual model can represent functional relationships, deal with interactions, non-linearity, and complexity in general, and can accommodate various statistical distributions.  However, they do not outperform other methods under every circumstance.   A model evaluation provides an objective way of measuring model performance and validation on independent datasets is the most robust approach.  Spatial and temporal scales are important to understand the distribution and abundance of organisms and inference will be weaker when based upon vague notions of scale than if precise notion of scale is used.  The adaptability of living systems is also highly questionable considering that we have never seen these effects before in the history of human-kind.  Predicting future changes based upon past observations is highly uncertain, however, ecosystems are highly adaptive and have a strong dependence on historical contingencies. 
          The author conducted a literature survey that includes the following words and their variations: spatial, fish, distribution, benth, geography, habitat, sea, ocean, marin, and model.  These articles are restricted to a period from 2005 to March 2010 within the fields of marine and freshwater biology, oceanography, and fisheries.  Seventy-five articles were then selected that presented models that were used or could be used for the projection of spatial distribution of marine populations.  Within each article, uncertainty within the previously mentioned criteria was assessed.  Overall, little attention is given to the various sources of uncertainties in models and consequently to uncertainties in the resulting projections.  Only 5 of the 75 studies explicitly accounted for the observation process in the model design; conceptual model uncertainty only accounted for one of the studies surveyed; uncertainty in the appropriateness of the numerical formula is addressed in one-fourth of the articles; parameter uncertainty was accounted for in 69%; 45% of the model evaluation was based upon visual comparison of predicted and observed distributions were infrequent; spatial and temporal scales were defined before modeling in 45% of the literature; only 4% discussed possible implications of ecological adaptability for projected changes. 
          Uncertainty in spatial projections has been poorly considered in marine ecological research, indicating that the current projections in marine biota distributions are likely poorly reliable.  There is an explicit trend in handling various sources of uncertainty in model projections but a more extensive study would be required to confirm this.  Highly uncertain or inaccurate projections could negatively harm managerial and conservation efforts, erasing what “success” we have created if future studies show that these uncertainties are indeed too great to ignore.  

Defining Scale in Fisheries: Small versus Large-scale Fishing Operations in the Azores

In the North Atlantic, both large- and small-scale fishing operations of the Azorean fishing fleet compete for the same limited resources, fishing grounds, and markets via in the coexistence of both large- and small-scale fishing operations.  These two sectors are very different in the scale of operation, employment generation, and degree of capital intensity and investment.  However, there is much debate over what exactly is large- and small-scale because there is no universal definition for these types of operations nor are there boundaries where one sector ends and the other beings.  These two sectors were compared using policy-relevant data so as to better understand the socio-economic importance, as well as develop future policies based upon a more holistic and ecosystem approach to fisheries management.  This comparison of the Azorean fleets showed that the small-scale fisheries were more sustainable overall because of their using less energy, providing more jobs to the community, and supplying fresher food for human consumption with a higher landed value. 
Carvalho, N., Edwards-Jones, G., Isidro E. 2011. Defining scale in fisheries: Small versus large-scale fishing operations in the Azores. Fisheries Research 109, 360–369. 

          There is long-standing assumption that large-scale fisheries are more economical.  However, due to declining world catches and fleet over-capacity and overcapitalization it is clear that new policies and strategies are needed.  The small-scale fishery was largely ignored in economic calculuations as it was seen as being inefficient and retrogressive and likely to gradually disappear as large-scale fishing expanded.  However, small-scale fisheries have withstood and even flourished despite longstanding marginalization.  Many studies show that small-scale fisheries are, in fact, sustainable resources which ensure sound policies of employment, income distribution, energy consumption, and product quality.  Small-scale fisheries account for anything between one-half to three-quarters of global fish production and employ 50 of the 51 million fishermen.
          However, these types of fisheries are poorly documented and provide no insight into future policy largely because there is no uniform structure to the definition of “small-scale”.  Each individual fishery and community is unique and distinct from others and there are numerous ways to divide fishing fleets into separate sectors.  A study was conducted to define the commercial fishing fleet in Azores as small or large using the socially-constructed definition.  This included surveys to acquire socio-economic data for the year 2005, surveying vessel owners/skippers, crew members, and auction buyers, resulting in survey of at least 41% of the active fishing vessel population.  This compared policy-relevant socioeconomic and environmental parameters, such as revenue, employment, by-catch and discards, and fuel consumption. 
          The first aspect of this survey defined small- and large-scale fleets using three main steps: (1) define the fishery as gear type/vessel size combination, (2) list gear type/vessel size combinations with their corresponding catch capacity, and (3) develop a cumulative percentage distribution of landed weight.  The small- and large-scale is then determined by 50% cut-off of cumulative landed value.  When more than one type of gear was used the prevalent gear (responsible for more than 80% of the landings) were used. 
          The study was based on the active use of 666 vessels, 2,160 fishermen, and live bait captures reaching almost 180 tonnes.  The final cut-off point reached 51.6%, corresponding to 63.3% cumulative landed value.  The Azorean fleet is traditionally known as a small-scale and sustainable fishery which has replaced larger commercial fisheries.  However, it is multi-segmented, targeting multiple species with a wide range of gears and currently exploits 50–60 of the 500 fish species within the ecosystem.  More than 90% of the fleet comprises vessels less than 12 meters in length, 25% of which were non-motorized.  Thus, the small-scale fishing fleet is dominated by small, old, wooden vessels of low power that on average use 31kW and weight 3.2 tonnes. 
          The small-scale sector encompasses 90% of the fishing fleet and employs almost three times more fishermen than its counterpart.  It is also less fuel-intensive, consuming half as much fuel per tonne of fish landed, and achieves a higher landed value per tonne.  The crew, having smaller landings, also has more time to clean and prepare fish for favorable presentation, fetching higher prices.  The average wage of the crew is higher than the minimum wage of alternative employment, however, it is still €250 less for employees of large-scale fisheries.
          Thus, small-scale fisheries have the potential to be profitable activities in coastal communities.  Not only do they employ more individuals in the North Atlantic, they meet more policy goals, such as catching fish for direct human consumption and deriving a higher economic value from each tonne of fish landed.  These fisheries can also maintain marginalized markets, depending less upon foreign and expensive sources of oil. 
          But there is not as much information about the economics of small-scale fisheries as needed for a full analysis.  They should become a top priority in development and research.  At the moment they serve as legitimate sources of income, employment, and food security, and development strategies should be encouraged to create synergistic effects between large- and small-scale fisheries.

A Review of EU Bio-Economics Models for Fisheries: The Value of a Diversity of Models

Fishing activities include an integration of biology and economics, a recent new branch within economics that has resulted in a growing interest and use of bio-economic models (BEM) as tools for policy-makers and fishermen to understand the feedback effects between human activity and natural resource dynamics.  Using mathematical representations of biological and economic systems known as bio-economic models (BEM), thirteen of these existing European Union models are presented and reviewed.  Used in either the Atlantic Ocean of the Mediterranean Sea, the thirteen models (AHF, BIRDMOD, BEMMFISH, COBAS, ECOCORP, ECONMULT, EIAA, EMMFID, FLR, MEFISTO, MOSES, SRRMCF, and TEMAS) help bridge the gap between localized anthropogenic and environmental pressures.  A diverse array of models is useful in helping policy-makers and fishermen answer real-life, complex fishery issues.  Presello et al (2011) focuses on how BEMs evaluated anthropogenic and biological interrelated components as well as EU policy surrounding fisheries. –Alyshia Silva
R. Prellezo, P. Accadia, J. Anderson, B. Anderson, E. Buisman, A. Little, J. Nielson, Jan Poos, J. Powell, C. Rockmann. 2011. A review of EU bio-economic models for fisheries: The value of a diversity of models. Marine Policy 36, 423–431

          There is an obvious and simple relationship between marine resources and users, extracting and fishing result in fish mortality, which is directly affected by biological components (predators, nutrient availability, etc.) and economic components (management, fuel costs, etc.).  The need for BEMs and integrated approaches to sustainable fisheries comes from the fact that both economics and biology play a crucial and interrelated role within marine fisheries.  BEM incorporates both biological variability as well as human behavioral traits using system dynamics, interactions and feedback mechanisms, key parameters, and data availability as well as their relationships with each other. 
          The two classifications of BEM are simulation (what if?) and optimization (what’s best?).  Simulation models strive to simulate a system of biological and economic components into a scenario to evaluate alternative management strategies or model external variables.  In comparison, optimization models are designed to find optimal solutions within a pre-defined objective, such as maximizing revenue, profit, harvest, fleet capacity, welfare, or minimizing day-at-sea costs or ecosystem impacts.        
          All thirteen of the models that were reviewed except MOSES could conduct simulations, while others models like EIAA, EMMFID, FLR, and SRRMCF can conduct both simulations and optimizations.
           Conclusions from these models are also dependent on input (effort, gear restrictions, area closures) and output (quota, catch, composition, maximum landing size).  BIRDMOD, BEMMFISH, COBAS, and MOSES solely model input controlled fisheries while the remaining models use both input and output regulated fisheries.
           BEMs are intended to reflect the main features of the fishery under analysis including the fact that different management regimes are in force in different areas for different fisheries.  However, many of the features of the models are not specific to regions and fisheries, so some aspects of these models, such as algorithms, are generic.  None of the models provide a complete biological overview and some are easily driven by routine settings of single-species or multi-species outputs, recruitment relationships, and growth and maturity.  There is a trade-off between the generality and complexity of BEMs.  SRRMCF, EIAA, ECONMULT, and EMMFID do not have a biological component whereas other models, such as the FLR and BIRDMOD, have as strengths lie in biological components.
          The BEMs’ economic components are heterogeneous but rely upon three common mechanisms: fleet and effort dynamics, price dynamics, and cost dynamics.  However, approaches to using these mechanisms vary, depending on the purpose of the model, availability of data and their structure, and the features of the fisheries.  Optimization or simulation models determine the relevance of the economic component and the approach used for its implementation, especially since both economic and biological data have different availabilities and detail. 
          Outputs of BEMs are mainly used by policy-makers and it is important that BEM results are standardized and made familiar so that communication between government and fishery experts is at its best.  These models are made to assess and compare stocks with sustainable levels with catch capabilities and economic profit, as well as incorporate biological indicators (e.g. sustainable stocks), capacity indicators (e.g. catch capability), economic indicators (short or long term economic goals), and sociological characteristics (e.g. employment), all of which are important to building sustainable fisheries. 
          The utility of a model depends on the framing of the question being asked.  While optimization models consider fixed prices, simulation models adopt elasticity functions to simulate marine dynamics.  However, there is room for further integration between biological and economic components, as made clear in the fact that three of the BEMs were purely economic (ECONMULT, EIAA, EMMFID, and SRRMCF) while the remaining nine had both of an economic and biological component.   However, all of these models require either economic or biological expertise. 

Net Economic Effects of Achieving Maximum Sustainable Yield in Fisheries

Increasing the economic performance of marine capture fisheries is becoming an increasingly important management strategy, specifically using the maximum economic yield (MEY).  Critics of MEY state that reducing the level of fishing necessary to achieve the target MEY will result in a subsequent loss of economic activity elsewhere in the economy.  Using an input-output framework within a bioeconomic model, the net economic effects of achieving MEY were calculated for short- and long-term performances when moving towards MEY.  Overall losses were felt by the community in the short-term while achieving MEY, but achieving MEY was found to be beneficial to the larger society in the long-term. 
Norman-Lopez, A., Pascoe, S. 2011.  Net economic effects of achieving maximum sustain yield in fisheries. Marine Policy 35, 489–495. 

          Relying on economic instruments, key management strategies for fisheries are done by maximizing economic efficiency.  This is done through the maximum economic yield (MEY), as defined as “the sustainable catch or effort level for a commercial fishery that allows net economic returns to be maximized”. The short and long term effects of achieving MEY in four Australian fisheries is estimated using input-output modeling framework.
          Although MEY is a yield or specific level of output, it is also a concept which can be constructed in a multitude of ways.  Different than maximum sustainable yield (MSY), MEY requires both input and output simultaneously to determine economically optimal levels.  MSY can result in yields similar to MEY, but only one such combination of input and output can result in MEY.  MEY can vary depending upon catch, size, and effort but can be defined as the combination of both effort and output and the capitalization of both revenue and cost curves. 
          Most fisheries are characterized by a number of fishing systems for a large variety of catch and MEY suggests that fleet reductions in excess of 50% may be necessary to maximize economic profits.  Achieving MEY will most likely be accompanied by reduction in employment and the total income of the crew declining (dependent on the payment system), while the individualized income of the crew member will increase.  Fishing at MEY reduces the number of vessels on the ocean to maximize economic efficiency for the remaining vessel owners as well as increase wages of the remaining crew members.  In dependent fishing coastal communities, higher incomes will lead to an increased demand for products in the local area, thereby stimulating production, incomes, and employment. 
          There will also be indirect and direct effects on the intermediary and final demand sectors in the economy–goods and services (e.g.,  fuel, equipment) and other sectors higher up the economic chain (e.g., processors, retailers).  The extent of the impact will depend upon the dependency of these sectors on the domestic fishing industry as well as the level of catches of MEY.  The final demand sector, as represented by the purchase of goods and services by consumers, will be affected due to the loss of income from the displaced crew of the closed-down vessels. 
          The four Australian fisheries that were targeted to reduce overfishing while moving the fishery closer to the target of maximum sustainable yield were the eastern tuna and billfish fishery (ETBF), the southern and eastern scalefish and shark fishery (SESSF), the northern prawn fishery (NPF), and a sector named the gillnet, hook, and trap sector (GHTS).  The first three represent two-thirds of the total AU$288 million of all the Commonwealth managed fisheries. 
          The input-output methodology includes the notion that the production of output requires input and a multiplier effect will occur to ensure the buying and selling of multiple goods and services to maintain the fishing system.  Three different types of effects make up the multipliers: the initial (or direct) effect, the production-induced effect, and the consumption-induced effect.  The initial effect refers to the initial amount of dollars spent; the production-induced effect is the purchase of extra goods to supply the extra demand; the consumption-induced effect is the proportion of the extra income that will be re-spent on final goods and services within the local economy.
          As stated previously, the reduction of fishing effort to achieve MEY will heavily depend upon the existing level of fishing effort, capacity, and stocks.  Within the model, fishing fleets of the four fisheries were reduced 45–60%, as a means to reduce overfishing, maintain biological sustainability, and improve economic performance.  Initially, this reduced total income and input usage in the economy but the profitability and incomes of the fisheries will increase in the long run when MEY is achieved. The structural adjustment has lowered costs within NPF, ETBF, CTS, and GHTS by, respectively, 27%, 18%, 57%, and 18%, while catches and revenue decreased by, respectively, 15%, 39%, and 5%, while catches increased in ETBF by 3%.  Prices for the fish remained unchanged due to prices being driven by world markets and exchange rate fluctuations rather than on quantity of domestic landings. 
          The net economic impacts are estimated once evaluating the direct effect (wages and profits to the fishery) and the production number and consumption-induced effects.  As a long term benefit, the reduction in fleet size increased fishery profits in three of the four sectors, the exception being GHTS.  This is an exception due to prices for repair and maintenance, and individualized vessels, rather than the entire section, have an increased profit.  This larger loss of labor and reduced capacity explains the larger loss of consumption, a direct negative effect on the fishing community.  In the short term, there are overall net economic effects on moving towards MEY, except for ETBF.  However, in the long term, the expected rise in catches of MEY is expected to result in a positive national economic effect.
          The two main effects of achieving MEY include fleet reductions (an initial change in profits and wages) and changes in revenue.  This analysis, overall, ignores the economic effects on the community and little research has been done as to the effects on the displaced crew.  Achieving MEY is clearly a challenge in the short run, but poses benefits for the community economically and sustainably by increasing wages for individuals and making environments more resilient in the long term.  

Impacts of Fishing Low-Trophic Level Species on Marine Ecosystems

Smith et al. (2011) explored the effects of fishing on low-trophic level (LTL) species.  They concluded that fishing these LTL species at conventional maximum sustainable yield (MSY) levels can have large impacts on the ecosystem, especially when they constituted a high proportion of the biomass in the ecosystem.  They also concluded that halving exploitation rates would result in lower impacts on the marine ecosystem while maintaining 80% of MSY. 
Smith, A., Brown, C., Bulman, C., Fulton, E., Johnson, P., Kaplan, I., Lozano-Montes, H., Mackinson, S., Marzloff, M., Shannon, L., Shin Y.J., Tam, J. 2011.  Impacts of Fishing Low-Trophic Level Species on Marine Ecosystems. Science 6046, 1147–1150

          Concern has risen over the effects of fishing on the structure and function of marine ecosystems, particularly LTL species because a majority of them are plankton feeders.  LTL species, which include anchovies, sardines, herrings, mackerel, krill, and capelin, are found in high abundance in schools or aggregations and account for 30% of global fisheries production. 
           LTL species are the principle means of transferring energy from plankton to larger predatory fish and upwards to marine mammals and seabirds.  Indirectly, seabirds, whales, and high- trophic level (HTL) species are affected by the maximum yield of LTL species. 
          To examine and summarize the broader effects of fishing LTL species, five-well studied ecosystem regions were modeled.   These regions included the California current, northern Humboldt, North Sea, southern Benguela, and southeast Australia.  For each ecosystem and model, five LTL species or groups were subjected to a range of fishing pressures which resulted in depletion levels relative to unfished biomass from zero to 100%.  Impacts on other species within the ecosystem were measured relative to biomass levels of unfished focal LTL populations and all other groups that were fished at current levels. 
          Widespread impacts of harvesting LTL species were found across the ecosystems and the LTL species that were selected.  The percentage of affected species increased with the level of depletion of the LTL species, but the exact extent of the impacts varied across LTL species.  Impacts were both positive and negative, and at times, counter-intuitive considering that there were severe impacts with low depletion levels.  Negative impacts were felt by marine mammals, seabirds, and commercial species, although the majority of these impacts were very small. 
          Overall, harvesting LTL species was found to have high impacts, although the species with high impacts were not consistent across all ecosystems.  Management implications then vary geographically; large impacts may require a change in overall harvest levels whereas LTL species with small impacts could be harvested at conventional levels.  The range of impacts could be explained by the relative abundance of the group in the ecosystem, the trophic level of the group, and the connectivity of the group in the food web. 
          Wider implications of exploitation of LTL species include the tension between global food security and the protection of biodiversity.  Lower exploitation rates can cause smaller impacts on the ecosystem but also sustain lower yield rates.  Lower impacts can be achieved by lowering the MSY exploitation levels to a target of 75% unexploited biomass for an LTL species.  This will cost less than 20% of long-term yield, implying lower fishing effort but long-term economic optimum levels.  This study supports the ongoing substantial yields of LTL species while achieving ecological objectives in the face of feeding the global population.  

Bycatch Governance and Best Practice Mitigation Technology in Global Tuna Fisheries

One of the greatest threats to global marine biodiversity is the overexploitation of bycatch and target species in marine capture fisheries.  The primary mortality sources of bycatch, as well as other linked species like seabirds, sea turtles, marine mammals, and sharks, are due to the purse seine and pelagic longline tuna fisheries.  Substantial progress is being made at identifying gear technology solutions but more comprehensive consideration is necessary to identify conflicts and mutual benefits from mitigation methods.  There is a lack of performance standards along with inadequate observer coverage for all oceanic purse seiners and incomplete data collection, all of which hinder assessing measures efficacy. 
Gilman, E.L. 2011. Bycatch governance and best practice mitigation technology in global tuna fisheries, Marine Policy 35, 590–509

          Underneath the large umbrella of state laws and international codes of conduct, States and ocean users develop and apply environmentally safe and selective fishing gear practices to maintain biodiversity, structure, processes, and services.  These practices are meant to minimize waste and bycatch, bycatch being defined as retained catch of non-targeted fish, discarded catch, and unobserved mortalities.  Bycatch may contain a variety of different species which are critical to maintaining the function and structure of the ecosystem as well as the continued provision of services provided by the ecosystem. 
          Bycatch and its overexploitation is the largest driver in the change and loss of marine biodiversity, primarily affecting k-selective species, species with sporadic recruitment, and even species with high fecundity.  In 1992–2001, averages of 7.3 million tons of fish were discarded annually, presenting 8% of the world catch.  Marine capture fisheries have negatively affected genetic diversity and environmental integrity, altering the distribution of fish size and reducing reproductive potential, possibly changing the evolutionary characteristics of populations.  Unsustainable bycatch fishing mortality of some species, in particular if they are keystone or foundation species, can cause extinction cascades, alter trophic interactions, simplify food webs, and change the overall functionality and structure of the system.  This directly affects the economic side of fisheries, adversely affecting future catch levels and resulting in allocation issues between fisheries. 
           Most tuna stocks are fully exploited, overfished, or depleted, as a result of use of purse seine, pelagic longline, and pole-and-line fisheries.  At the moment, it is not possible to sustainably increase catches of stock without increasing bycatch levels, chiefly of sea turtles, seabirds, marine mammals, sharks, and juvenile and unmarketable finfish in pelagic and purse seine fisheries.  There are multitudes of ways of mitigating bycatch via gear technology, including ways that are specific to area as well as species.  To reduce bycatch of birds fishermen should avoid peak periods of bird foraging, reduce detection of bait by dyeing it blue, and limit bird access to baited hooks through underwater setting devices.  Using “weak” circle hooks, large whole fish bait instead of squid, setting gear deeper and avoiding hotspots can minimize bycatch of sea turtles, sharks, and marine mammals. 
          Fishermen themselves must be tapped into for their local knowledge to find effective and practical fishery-specific bycatch solutions.  Participation from these fishermen could also lead to the fishing industry themselves developing a sense of ownership for bycatch reduction methods.  Methods that are shown to minimize, reduce interactions with, and offset mortality of bycatch should be implemented if they are practical, safe, and economically viable or beneficial.  Also, most importantly, a viable mitigation method will not increase bycatch of other unwanted bycatch species or sizes. 
          Five tuna Regional Fishery Management Organizations (RFMOs) were established to manage global fisheries for tuna and tuna-like species; the Commission for the Conservation of Southern Bluefin Tuna (CCBST), Indian Ocean Commission (IOTC), Inter-American Tropical Tuna Commission (IATTC), International Commission for the Conservation of Atlantic Tunas (ICCAT), and Western and Central Specific Fisheries Commission (WCPFC).  All except for IATTC had binding measures on longline sea-bird bycatch; IOTC, ITAAC, and WCPFC require gear technology methods to mitigate turtle bycatch in purse seine fisheries ; IOTC, ITAAC, ICCAT, and WCPFC restrict shark finning practices and prohibit the retention of thresher shark species; all except CCBST have adopted legally binding measures to mitigate the bycatch of juvenile/small tunas and other unmarketable species; and only ITAAC have quantifiable performance standards. 
          There is also a need for observer data collection, of which only two organizations, IATTC and WCPFC, have close to 100% observer coverage.  To support robust assessments of bycatch there must be substantial increases in bycatch data collection, employment of standardized monitoring, open access to regional- and national-level observer program datasets, and determination of how individual datasets can be incorporated. 
          Illegal, unreported, and unregulated (IUU) tuna fishing further exacerbates overexploitation of bycatch, reaching an annual value of $581 million, the illegal proportion of total tuna landings estimated to be a total of 5%.  ICCAT, CCSBT, and IATTC have adopted documentation schemes which are generally unsuccessful in deterring IUU fishing due to weaknesses of corruption, inadequate laws, lack of resources for surveillance, and mis-labeling of seafood.  
          The overexploitation of tuna and tuna bycatch can be attributed to tuna-RFMO’s inability to fully adopt conservation and management measures via consensus-based decision-making and ability for members to opt out of adopted measures.  This is exacerbated by conflicting objectives of distant fishing nations that wish to maintain their dominance and control of fishing populations.  This prevents RFMOs from adopting best practice methods as well as resulting in low compliance by Member States.  Commercial viable changes in gear technology and methods can in fact reduce nearly all tuna bycatch in tuna fisheries to nominal levels.  These methods include voluntary initiatives such as input and output controls, fleet communication, and industry self-policing.

Climate Change and Marine Capture Fisheries

R.I. Perry’s paper Potential impacts of climate change on marine wild capture fisheriespublished in the Journal of Agricultural Science (Perry 2011) reviews data regarding climate change and its effects on marine wild capture fisheries.  Climate change in marine ecosystems is a broad and inclusive matter; understanding its synergistic effects on both the marine world and human world is crucial to taking the next steps of reducing the uncertainties of climate impacts while creating adaptive, resilient ecosystems that can benefit both social-environmental systems.–Alyshia Silva  
Perry R. 2010. Potential impacts of climate change on marine wild capture fisheries: an update. The Journal of Agricultural Science 149 63–75

          About 20% of the world’s population relies on marine wildlife capture as a means of subsistence­­­­­—a factor in much of the developing world’s economy—and for jobs in the marketing and processing sectors.  However, due to growing pressures ranging from human to environmental stressors, the ability of marine ecosystems to continue meet the world’s needs is becoming questionable. 
          Many studies have shown that climate change is directly affecting fish abundance and location.  The warming of waters near the equator causes a shift in marine populations pole-ward, encouraging their seasonal migrations sooner and for longer periods of time, while moving them away from historical fishing grounds.
          Using a range of physical conditions, modeling studies have projected ranges shifts of 45–60 km per decade.  Using a high CO2 emission scenario, an estimated 80% of species will move towards the poles, resulting in local extinctions of fish in sub-polar, tropical, and semi-enclosed bodies of water.  Overall, however, little change in global maximum catch potential will occur, meaning higher-latitude areas will increase on average 30­–70%, while the average of the tropics dropped to 40%.  It is developing countries nearer to the equator that will be most harmed by the pole-ward shift of fish population while developed countries to the north will benefit from increased fish populations.  The low-emission scenario produced less clear results, but in a similar nature.  
          Primary production within marine ecosystems plays a vital, yet at times confusing, role within climate change modeling systems.  Coupling complex food webs (predator and competitor interactions), biology, and physics, model formulations of increased primary production led to unexpected declines in more abundant catches and increased populations for some threatened species. 
          Declines of phytoplankton biomass in eight out of the ten oceans were attributed to increasing sea surface temperatures and observational increases in surface air temperatures of 6°C over the past 50 years is leading to loss of perennial ice, coral bleaching, retreating glaciers, and a net decrease of primary production.  
          Zooplankton play a crucial role within the marine ecosystem, shifting their range to a greater extent and faster than any other marine or terrestrial group.  Within an experimental and simplified marine food web that included both zooplankton and phytoplankton, increased temperatures led to blooms of zooplankton and decreases in primary productivity of phytoplankton.  This led to an overall decrease in marine biomass; these studies conclude that even small temperature shifts can lead to huge impacts on the ecosystem. 
          The combined pressures of fishing for an increasingly demanding human population and global climate change appear to be too much for the marine ecosystem to adequately recover from.  The potential costs of adapting to a 2°C warmer world by 2050 include estimated global losses in landed catch value of $7–$19 billion for developing nations and $2–$8 billion for the developed world.

          Climate change will have a direct impact on marine ecosystems, food security, economics, and politics.  Climate change and its effects will directly negatively impact the developing world while possibly benefitting the developed world, a problem of environmental justice.  To better handle the currently stressed marine world we must couple social-ecological systems to develop a resilient yet adaptive human and ecological system that can adequately respond swiftly and effectively.  

Climate Change and Marine Capture Fisheries

R.I. Perry’s paper Potential impacts of climate change on marine wild capture fisheriespublished in the Journal of Agricultural Science (Perry 2011) reviews data regarding climate change and its affects on marine wild capture fisheries.  Climate change in marine ecosystems is a broad and inclusive matter; understanding its synergistic effects on both the marine world and human world is crucial to taking the next steps of reducing the uncertainties of climate impacts while creating adaptive, resilient ecosystems that can benefit both social-environmental systems. —Alyshia Silva
Perry R. 2010. Potential impacts of climate change on marine wild capture fisheries: an update. The Journal of Agricultural Science 149 6375

          About 20% of the world’s population relies on marine wildlife capture as a means of subsistence­­­­­­ —a factor in much of the developing world’s economy— and for jobs in the marketing and processing sectors.  However, due to growing pressures ranging from human to environmental stressors, the ability of marine ecosystems to continue meet the world’s needs is becoming questionable. 
          Many studies have shown that climate change is directly affecting fish abundance and location.  The warming of waters near the equator causes a shift in marine populations pole-ward, encouraging their seasonal migrations sooner and for longer periods of time, while moving them away from historical fishing grounds.
          Using a range of physical conditions, modeling studies have projected ranges shifts of 4560 km per decade.  Using a high CO2 emission scenario, an estimated 80% of species will move towards the poles, resulting in local extinctions of fish in sub-polar, tropical, and semi-enclosed bodies of water.  Overall, however, little change in global maximum catch potential will occur, meaning higher-latitude areas will increase on average 30­70%, while the average of the tropics dropped to 40%.  It is developing countries nearer to the equator that will be most harmed by the pole-ward shift of fish population while developed countries to the north will benefit from increased fish populations.  The low-emission scenario produced less clear results, but in a similar nature. 
          Primary production within marine ecosystems plays a vital, yet at times confusing, role within climate change modeling systems.  Coupling complex food webs (predator and competitor interactions), biology, and physics, model formulations of increased primary production led to unexpected declines in more abundant catches and increased populations for some threatened species. 
          Declines of phytoplankton biomass in eight out of the ten oceans were attributed to increasing sea surface temperatures and observational increases in surface air temperatures of 6°C over the past 50 years is leading to loss of perennial ice, coral bleaching, retreating glaciers, and a net decrease of primary production.  
          Zooplankton play a crucial role within the marine ecosystem, shifting their range to a greater extent and faster than any other marine or terrestrial group.  Within an experimental and simplified marine food web that included both zooplankton and phytoplankton, increased temperatures led to blooms of zooplankton and decreases in primary productivity of phytoplankton.  This led to an overall decrease in marine biomass; these studies conclude that even small temperature shifts can lead to huge impacts on the ecosystem. 
          The combined pressures of fishing for an increasingly demanding human population and global climate change appear to be too much for the marine ecosystem to adequately recover from.  The potential costs of adapting to a 2°C warmer world by 2050 include estimated global losses in landed catch value of $7$19 billion for developing nations and $2$8 billion for the developed world.
          Climate change will have a direct impact on marine ecosystems, food security, economics, and politics.  Climate change and its affects will directly negatively impact the developing world while possibly benefitting the developed world, a problem of environmental justice.  To better handle the currently stressed marine world we must couple social-ecological systems to develop a resilient yet adaptive human and ecological system that can adequately respond swiftly and effectively.