Will American consumers pay more for eco-friendly labeled canned tuna? Estimating US consumer demand for canned tuna varieties using scanner data

This study estimates consumer demand for eco-friendly labeled canned tuna products in two distinct US marketing channels, conventional and natural supermarkets, to evaluate market-based incentives for conservation measures that affect fishing costs and retail prices. Using retail scanner data, this paper finds that US consumer demand for canned tuna varies depending on the species of tuna, what gear type was used, whether the can is sold in natural food or conventional supermarkets, and whether canned product is or is not certified as eco-friendly. The paper's main conclusions are that retail price premiums for eco-friendly products face upper limits due to consumer responses to higher prices, and are most effective when coupled with: (1) inelastic own-price elasticity of demand; (2) price premium signals that are transmitted from retail markets to raw material producers; and (3) limited retail consumption substitution possibilities with lower-priced conventional products that help maintain price premiums and that otherwise create conservation disincentives by increasing conventional supply. Results from this paper not only have unique implications for various forms of international tuna fisheries policy that incorporates or anticipates change in market behavior, but also could serve as a scientific reference to clarify the trade disputes.     

An account of the dolphin-safe tuna issue in the UK

Virtually all canned tuna in the UK is labelled as dolphin-safe despite the fact that the market is almost exclusively skipjack tuna. It is thus not implicated in the dolphin bycatch problem associated with the yellowfin tuna of the Eastern Tropical Pacific consumed in the USA. There were a range of different motives among processors and retailers in adopting the labelling scheme in the UK. The scheme may be more of a marketing ploy, promoted by the major processors, than an eco-label forced upon the market through consumer and environmentalist power. Environmental groups can nonetheless be credited with driving the development of initial first-party labelling schemes into the present, more independent, second-party scheme. The scheme now in place in the UK is different from that in the USA, being preventative, ensuring that tuna sold does not become dolphin-un-safe, rather than actively addressing a specific existing environmental problem.     

Planning the use of fish for food security in the Pacific

Fish is a mainstay of food security for Pacific island countries and territories (PICTs). Recent household income and expenditure surveys, and socio-economic surveys, demonstrate that subsistence fishing still provides the great majority of dietary animal protein in the region. Forecasts of the fish required in 2030 to meet recommended per capita fish consumption, or to maintain current consumption, indicate that even well-managed coastal fisheries will only be able to meet the demand in 6 of 22 PICTs. Governments of many PICTs will need to increase local access to tuna, and develop small-pond aquaculture, to provide food security. Diversifying the supply of fish will also make rural households in the Pacific more resilient to natural disasters, social and political instability, and the uncertainty of climate change.     

Prospects for an international tuna resource owners' cartel

The paper briefly describes the world tuna industry and develops estimates of the elasticities of supply and demand for tuna harvested in the Pacific Islands Region (PIR), which supplies around one-third of the world catch. The elasticity estimates are used to estimate the effect on the revenues received by the PIR of a small increase in the royalty charged for access to the resource. The results suggest that there is a potential for the tuna resource owners of the region to improve their returns through collective action and the exercise of market power.     

The tuna offshore unit: concept and operation

A radical new concept for delivering Bluefin Tuna to the marketplace is proposed offering offshore technologies to the world's fish industry. The Tuna Offshore Unit is a 190-m length and 56-m breadth vessel that resembles a semisubmersible with a catamaran hull and internal arrangement of fish-pools that can be enlarged in operation by deploying a rigid net for fish cultivation. Using the vessel, juvenile bluefin tuna are purchased at selling centers (e.g., hatcheries), fattened to a total bio-mass of 1200 tons over a period of nine months in warm-water climates and delivered to live fish markets during periods of high demand. This paper describes the main features, working principles, and design challenges of the Tuna Offshore Unit.     

A spatial ecosystem and populations dynamics model (SEAPODYM) – Modeling of tuna and tuna-like populations

An enhanced version of the spatial ecosystem and population dynamics model SEAPODYM is presented to describe spatial dynamics of tuna and tuna-like species in the Pacific Ocean at monthly resolution over 1° grid-boxes. The simulations are driven by a bio-physical environment predicted from a coupled ocean physical–biogeochemical model. This new version of SEAPODYM includes expanded definitions of habitat indices, movements, and natural mortality based on empirical evidences. A thermal habitat of tuna species is derived from an individual heat budget model. The feeding habitat is computed according to the accessibility of tuna predator cohorts to different vertically migrating and non-migrating micronekton (mid-trophic) functional groups. The spawning habitat is based on temperature and the coincidence of spawning fish with presence or absence of predators and food for larvae. The successful larval recruitment is linked to spawning stock biomass. Larvae drift with currents, while immature and adult tuna can move of their own volition, in addition to being advected by currents. A food requirement index is computed to adjust locally the natural mortality of cohorts based on food demand and accessibility to available forage components. Together these mechanisms induce bottom-up and top-down effects, and intra- (i.e. between cohorts) and inter-species interactions. The model is now fully operational for running multi-species, multi-fisheries simulations, and the structure of the model allows a validation from multiple data sources. An application with two tuna species showing different biological characteristics, skipjack (Katsuwonus pelamis) and bigeye (Thunnus obesus), is presented to illustrate the capacity of the model to capture many important features of spatial dynamics of these two different tuna species in the Pacific Ocean. The actual validation is presented in a companion paper describing the approach to have a rigorous mathematical parameter optimization [Senina, I., Sibert, J., Lehodey, P., 2008. Parameter estimation for basin-scale ecosystem-linked population models of large pelagic predators: application to skipjack tuna. Progress in Oceanography]. Once this evaluation and parameterization is complete, it may be possible to use the model for management of tuna stocks in the context of climate and ecosystem variability, and to investigate potential changes due to anthropogenic activities including global warming and fisheries pressures and management scenarios.     

Market assessment on the incentives and disincentives for the adoption of sustainable practices along the tuna value chain in Region 12, Philippines

With the world's increasing demand for tuna and the subsequent exhaustion of tuna stocks, this paper tries to assess the different attempts and/or practices that lead towards sustainability along the tuna value chain in the Philippines. In terms of economic gains, the net margins analysis, was used to measure the level of income of the actors which was considered as a factor that could possibly incentivize the adoption of sustainable practices, along with other market phenomena which were reviewed in this paper. These significant practices in the market include the provision of price premiums for the capture of mature tuna and the stringency of the market in terms of eco-labelling and certifications in contrast to the indifference of the local Philippine market in terms of preference. Lastly, having purse seine as a less sustainable method of tuna fishing, it was seen that there is a lack of incentive for them to adopt more sustainable practices.     

Economic impact of climate change and climate change adaptation strategies for fisheries sector in Solomon Islands: Implication for food security

Fisheries resources play a major role in the national economy and to food security in Solomon Islands. Climate change is likely to have a substantial impact on fish production that can lead to a fragile food security condition in the country. This paper assesses the potential economic impact of three important climate change adaptation strategies – natural resource management (NRM), fish aggregating devices (FAD) and aquaculture – in Solomon Islands. The study used a country-specific partial equilibrium economic model with six fish sub-sectors and analyzed potential impact of alternate climate change adaptation strategies for 2035 and 2050. The modeling and scenario analyses show that total fish demand is likely to surpass domestic fish production in 2050. Without appropriate climate adaptation strategy, per capita consumption of domestically produced fish will decline, which has serious negative food security implications for the country. The economic (welfare) analysis conducted based on modeling results show that the national level net economic gains due to climate change adaptation strategies are substantial. If cost and topographic conditions permit, low-cost inshore FADs are expected to be a good mechanism for augmenting domestic supplies of tuna and similar species in Solomon Islands.     

The influence of economic factors in the change of fishing strategies of anchored FAD fishers in the face of declining catch,General Santos City,Philippines

Decline in tuna fish stocks due to weak enforcement of regulations on fishing effort poses a challenge to the sustainability of tuna fishery. Intervention programs to address this problem require an understanding of the operational behaviour of the fishers and how various socioeconomic factors may impact fishers’ decisions to continue or discontinue their fishing efforts. A semi-structured interview questionnaire was developed to find whether fishers are willing to keep, change their fishing strategies or exit the fishery if their regular catch will decline by half. Boat captains, assistant boat captains and crew from General Santos City, Lupon, Mati City and Governor Generoso in the Philippines (n=293) were purposively selected for interviews. Results show that fishers from General Santos City with ancillary industries and Lupon with fewer economic development are more willing to adapt or change their fishing strategies. The catch value or price was found to have a strong influence on the likelihood that anchored FAD tuna fishers will adapt or change their fishing strategy when their catches decline. Fishers whose catch fetched a price of PhP 151.00 (US$ 3.48) and above Php 200 (US$ 4.61) have 80% probability to change their fishing strategy. The proportion of catch sold also had a high influence on the decisions to adapt in the fishery with fishers selling 36% and 73% of their catches have 100% and 70% probability to adapt. The results suggest a reluctance to exit the fisheries even when tuna fishing is no longer economically viable, fishers opt to adapt.     

基于计算机视觉的3种金枪鱼属鱼类形态指标自动测量研究

金枪鱼类是我国远洋渔业重要的捕捞对象,其形态指标对研究金枪鱼类的生长、发育和生活史具有重要意义。人工测量形态指标是一种非常繁琐且低效率的测量方法,而计算机视觉是一种高效和客观的自动测量方法。因此,本文通过计算机视觉库OpenCV对3种金枪鱼类图像进行预处理,主要利用双边滤波、灰度变换、二值化处理和提取轮廓等图像处理技术得到金枪鱼类形态轮廓图像。根据预先选定的特征点,利用计算机视觉技术遍历轮廓图像上所有的像素点,并自动定位出每张轮廓图像的预选特征点共17个。利用计算机视觉技术遍历得到的特征点位置,自动测量出3种金枪鱼的形态指标像素长度,并计算出形态指标实际长度。还分析自动测量与人工测量形态指标的绝对误差和相对误差。研究结果表明,通过计算机视觉技术对3种金枪鱼的形态指标的自动测量效果较好,大眼金枪鱼、黄鳍金枪鱼和长鳍金枪鱼的12个形态指标的绝对误差范围分别为0～1.46 cm、0～1.73 cm、0～1.32 cm,其相对误差范围分别为0.01%～5.84%、0%～6.17%、0%～6.89%。本研究以期为金枪鱼类智能识别提供前期工作基础,也为其他鱼类自动测量研究提供基础参考。     

Biomarkers for endocrine disruptors in three species of Mediterranean large pelagic fish

The hypothesis that Mediterranean top predator species, such as large pelagic fish, are potentially at risk due to endocrine disrupting chemicals (EDCs), is investigated. The potential estrogenic effects of PHAHs in three fish species of commercial interest, the top predators bluefin tuna (Thunnus thynnus thynnus), swordfish (Xiphias gladius), and Mediterranean spearfish (Tetrapturus belone), were investigated using vitellogenin (Vtg), zona radiata proteins (Zrp) and mixed function oxidases (EROD, BPMO) as diagnostic tools. High induction of Vtg and Zrp was detected by western blot and ELISA techniques in adult males of X. gladius and T. thynnus thynnus, suggesting that these species are at high toxicological risk in the Mediterranean sea. Comparison of BPMO and EROD activities in the three species indicated, both in male and female, much higher MFO activity in bluefin tuna. This data suggests high exposure of this species to lipophilic xenobiotic contaminants in the Mediterranean environment.     

Restructuring the Chinese seafood industry,global challenges and policy implications

This article discusses how the Chinese seafood industry will affect the rest of the world's fishing industries. The analysis is based on theories of economic comparative advantage, the international division of labour and the internationalization process related to trade activities. Given the increasing domestic demand for fish in China, the limited availability of domestic fish stocks and less success for farmed marine fish in China are considered some of the most important factors in restricting the growth in Chinese seafood production. The necessity of raw fish imports into China may increase pressure on global fish stocks and international fish prices, resulting in tighter supplies worldwide and higher seafood prices for the Chinese. Sustainable fish harvests and trade require stronger fishery management, in particular in the relations between seafood companies and governments along the entire international value chain supplying China. Such structural changes may allow new value-added possibilities for fish farming and the upgrading of certain fish species for human consumption that were previously utilized purely for fish feed.     

Predatory fish and their prey — an overview of trophic interactions in the fish communities of the west and south coasts of South Africa

Fish communities over continental shelves are of three types: pelagic, rocky reef and soft substrata. The pelagic community of the South African west coast is dominated by clupeiform fish, which are the principal prey of snoek, the dominant piscivorous teleost in the area, and other fish, including tuna and pelagic sharks. Keystone prey species are broadly similar on the South African south and west coasts, but predator composition differs. Studies of rocky reef fish suggest that the fauna of the South Coast is more diverse than that of the West, the West Coast having fewer species and only two reef fish species being taken in linefisheries. Feeding interactions of some of the dominant species have been established, but the status of commercially less important fish such as elasmobranchs and small species is poorly known. The community and feeding interactions of fish living over soft substrata are better known and part of this fauna is taken by demersal trawlers. The two species of Cape hake dominate the communities on both coasts, but the fauna is more diverse on the Cape south coast. Generally, much of the present ichthyological knowledge is derived from the ecologically narrow perspective of commercial fisheries. Nevertheless, the patterns of diversity appear to conform to previous work, which has indicated a lower species diversity in the Atlantic than in the Indian Ocean. Knowledge of commercially unimportant fish is fragmentary, and understanding of the ecological interactions on the South Coast generally lags that of the West.     

基于高通量测序技术解析鲣鱼(Katsuwonus pelamis)鱼油和鱼白调控肠道菌群结构作用

本研究利用高通量测序技术分析小鼠喂食鲣鱼(Katsuwonus pelamis)鱼油和鱼白酶解液后肠道微生物的多样性、群落组成以及结构的变化,探讨高蛋白、高脂肪饮食对人类健康的影响。研究结果显示:喂食鱼油组小鼠的肠道微生物丰富且多样。在门水平上,对照组和鱼油组的优势菌门为拟杆菌门(Bacteroidetes);鱼白组的优势菌门为厚壁菌门(Firmicutes)。在科水平上,对照组和鱼油组中的优势菌科为Muribaculaceae;鱼白组中的优势菌科为毛螺菌科(Lachnospiraceae)。在属水平上,对照组和鱼油组中的优势菌属为Muribaculum;鱼白组中的优势菌为Lachnoclostridium;对照组、鱼油组和鱼白组小鼠的肠道微生物群落中瘤胃球菌属(Ruminococcus)和拟杆菌属(Bacteroides)等丰度较高。在种水平上,对照组和鱼油组中的优势菌为Muribaculum intestinale;鱼白组中的优势菌为解糖梭菌(Clostridium saccharolyticum)。研究结果证明鲣鱼鱼油和鱼白可以调节菌群结构和组成,增加肠道有益菌,减少病原菌的丰度等。     

Feeding ecology of Japanese Spanish mackerel(Scomberomorus niphonius) along the eastern coastal waters of China

Feeding activities provide necessary nutrition and energy to support the reproduction and development of fish populations. The feeding ecology and dietary plasticity of fish are important factors determining their recruitment and population dynamics. As a top predator, Japanese Spanish mackerel(Scomberomorus niphonius) supports one of the most valuable fisheries in China. In this study, the feeding ecology and diet composition of Japanese Spanish mackerel spawning groups were analysed based on samples collected from six spawning grounds along the eastern coastal waters of China during spring(March to May) in 2016 and 2017. Both stomach contents and stable isotope analysis were conducted. Stomach content analysis showed that spawning groups of Japanese Spanish mackerel mainly fed on fish, consuming more than 40 different prey species. Diets were significantly different among sampling locations. The most important prey species were Stolephorus in Fuzhou, Japanese anchovy Engraulis japonicus in Xiangshan, Euphausia pacifica in Lüsi, sand lance Ammodytes personatus in Qingdao and Weihai, and Leptochela gracilis in Laizhou Bay. Stable isotope analysis showed that the trophic level of Japanese Spanish mackerel was relatively high and generally increased with latitude from south to north. In the 1980 s, the diet of Japanese Spanish mackerel was dominated solely by Japanese anchovies in the eastern coastal waters of China. The results in the present study showed that the importance of Japanese anchovies declined considerably, and this fish was not the most dominant diet in most of the investigated waters. Both the spatial variations in diet composition and changes in the dominant diet over the long term indicated the high adaptability of Japanese Spanish mackerel to the environment. Combining the results of stomach analysis and stable isotope analysis from different tissues provided more comprehensive and accurate dietary information on Japanese Spanish mackerel. The study provides essential information about the feeding ecology of Japanese Spanish mackerel and will benefit the management of its populations in the future.     

Organic waste impact of capture-based Atlantic bluefin tuna aquaculture at an exposed site in the Mediterranean Sea

A variety of pelagic and benthic parameters were measured at an aquaculture farm used for the fattening of Atlantic bluefin tuna (Thunnus thynnus) which is located at an exposed site (700 m from the coast, average bottom depth of 45 m and average current speed of 6 cm s⁻¹) in the Mediterranean Sea. The objective was to test whether modern off-shore tuna fattening industries can exert a sustainable organic waste impact on the receiving environment as has been reported for the offshore culture of more traditional Mediterranean species such as sparids. In the water column, the concentration of phytopigments, organic matter, heterotrophic bacteria and the taxonomic abundance of mesozooplankton (at the species level) were assessed. In the sediment, we assessed the concentration of reduced sulphur pools, phytopigments, organic matter, heterotrophic bacteria and the taxonomic abundance of meiofauna (at the taxa level) and nematodes (at the genus level). For most parameters, we found no substantial differences between farm and control sites. Deviations of farm values from control values, when they occurred, were small and did not indicate any significant impact on either the pelagic and benthic environment. Deviations were more apparent in the benthic compartment where lower redox potential values, higher bacterial production rates and a change in nematode genus composition pointed out to early changes in the sediment's metabolism. In addition, indigenous potential pathogenic bacteria showed higher concentration at the fish farm stations and were a warning of an undesirable event that may become established following aquaculture practice in oligotrophic environments. The overall data from this study provide extensive experimental evidence to support the sustainability of modern offshore farming technology in minimizing the hypertrophic-dystrophic risks associated with the rapidly-expanding tuna-fattening industry in the Mediterranean Sea.     

基于数据挖掘算法的WCPO金枪鱼围网渔情预测研究

利用数据挖掘方法对1990年1月—2001年7月10余年的WCPO金枪鱼围网作业生产数据以及该时段的18个与WCPO金枪鱼围网产量相关的海洋环境因子进行分析,将信息增益分析技术和基于粗糙集的属性化简方法相结合用以确定影响WCPO金枪鱼围网产量的关键因子集。利用多元回归分析方法建立基于关键因子集的预测模型,经过大量试验对比选择较佳的预测模型,达到了理想的效果。同时,验证了所确定关键因子集的可靠性,有效性。首次利用多种数据挖掘方法相结合的方式对多种影响因子进行分析,开展渔情预报研究,达到了较好的效果,为渔情预报研究提供了一种新思路,同时为渔业生产提供了可靠的依据。     

Habitat overlap between southern bluefin tuna and yellowfin tuna in the east coast longline fishery - implications for present and future spatial management

Southern bluefin tuna (SBT) are presently a quota-managed species in the multi-species eastern Australian tuna and billfish longline fishery (ETBF). Capture of SBT is regulated by quota, as is access to regions likely to contain SBT. A habitat prediction model combining data from an ocean model and pop-up satellite archival tags is used to define habitat zones based on the probability of SBT occurrence. These habitat zones are used by fishery managers to restrict access by ETBF fishers to SBT habitat during a May-November management season. The zones display a distinct seasonal cycle driven by the seasonal southward expansion and northward contraction of the East Australia Current (EAC) and as a result access by fishers to particular ocean regions changes seasonally. This species also overlaps with the commercially valuable yellowfin tuna (YFT), thus, we modified the SBT model to generate YFT habitat predictions in order to investigate habitat overlap between SBT and YFT. There is seasonal variation in the overlap of the core habitat between these two species, with overlap early (May-Jul) in the management season and habitat separation occurring towards the end (Aug-Nov). The EAC is one of the fastest warming ocean regions in the southern hemisphere. To consider the future change in distribution of these two species compared to the present and to explore the potential impact on fishers and managers of the future, we use future ocean predictions from the CSIRO Bluelink ocean model for the year 2064 to generate habitat predictions. As the ocean warms on the east coast of Australia and the EAC extends southward, our model predicts the suitable habitat for SBT and YFT will move further south. There was an increase in the overlap of SBT and YFT habitat throughout the management season, due to regional variation of each species’ habitat. These results illustrate that a management tradeoff exists between restricting fisher access to SBT habitat and allowing access to YFT habitat. We suggest that some options to address this tradeoff are possible by identifying the seasonal variability of the overlap.     

Yield and catch changes in a Mediterranean small tuna trap: a warming change effect?

Since the 17th century, the Tonnarella of Camogli, a small tuna trap, has been used to catch pelagic fish along the western coast of the Portofino Promontory (Ligurian Sea, Northwestern Mediterranean). The availability of long‐term datasets on fish yields (1950–1974 and 1996–2011), with information related to the seawater temperatures and the North Atlantic Oscillation (NAO), has allowed us to study the qualitative and quantitative changes in fish yields in the last decade and the possible relationships with the seasonal anomalies of temperature that have occurred in the Ligurian Sea. In 1950–1974, yields remained relatively constant over time (average of 35.6 ± 8.7 t·year^?1). From 1996 through 2011, yields were high (42.9 ± 15.9 t·year^?1) but inconsistent with strong annual variability in catches. The primary catches are Seriola dumerili, Auxis rochei, Trachurus spp. and Sarda sarda. Changes in species composition have occurred as well: S. dumerili, Sardinella sp. and Belone belone have appeared recently. Moreover, a significant decrease in the boreal scombroid (Scomber scombrus) and an increase of warm‐temperate carangids and other typically Southern Mediterranean species such as Coryphaena hippurus and Sphyraena viridensis, appear to be linked to the warming of the surface water layer, particularly evident in the Ligurian Sea, for the last 10 years. The analysis of this kind of trend may be a powerful tool for assessing structural changes of the pelagic fish community in the Ligurian Sea (Northwestern Mediterranean).     

Optimising fisheries management in relation to tuna catches in the western central Pacific Ocean: A review of research priorities and opportunities

Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries.