Coastline degradation, as well as subsequent ecosystem loss, has long been attributed to anthropogenic stress and is an all too familiar issue affecting coastal habitats. Should management and conservation efforts fail to improve the quality of coastal ecosystems and the services they provide, they may be irrevocably damaged. A significant limitation to conservation efforts is often the ability to track change in seagrass meadows due to the significant time and cost of monitoring efforts in underwater habitats. Remote sensing is often a tool used to improve our knowledge of habitat status, however, ground-truthing remote sensing results is difficult when historical data is required. We apply an innovative and resourceful approach to the attainment of data to check the status of seagrass meadows from resources that are available in many areas due to the collection of other data sets. We employ the use of underwater digital photographs originally taken for monitoring sediment movement patterns. We were successfully able to develop a method to critically and easily evaluate these photographs for habitat status, enabling the generation of a data set unable to be obtained in other ways. This method can further be utilised in a citizen science project, for other underwater digital photographs, to support the assessment of coastal submerged ecosystem habitat status.
Marine protected areas (MPAs) are a key strategy for mitigating the impacts of fisheries, but their designation can be controversial, and there is uncertainty surrounding when and where MPAs are most effective. Evidence synthesis that collates primary research on MPA effectiveness can provide a crucial bridge between research, policy and practice. However, reviews vary in scope and rigour, meaning decision-makers face the challenge of identifying appropriate reviews. Documenting differences amongst reviews can therefore support nonspecialists in locating the most relevant and rigorous reviews and can also assist researchers in targeting evidence gaps. We addressed these priorities by systematically searching for reviews examining effectiveness of MPAs for biodiversity, critically appraising methods used and categorizing review scope. The 27 reviews assessed overlapped in scope (suggesting some redundancy) and differed substantially in reliability. Key strengths related to the effects of MPAs on fish abundance and the influence of MPA size and age on effectiveness. However, several gaps were noted, with some questions not addressed and others lacking highly reliable syntheses – importantly, the latter may create the perception that particular questions have been adequately addressed, potentially deterring new syntheses. Our findings indicate key aspects of review conduct that could be improved (e.g. documenting critical appraisal of primary research, evaluating potential publication bias) and can facilitate evidence-based policy by guiding nonspecialists to the most reliable and relevant reviews. Lastly, we suggest that future reviews with broader taxonomic coverage and considering the influence of a wider range of MPA characteristics on effectiveness would be beneficial.
Reducing the capture of small fish, discards, and by-catch is a primary concern of fisheries mangers that propose to maintain high yields, species diversity, and associated ecosystem functions. Modified fishing gear is one of the primary ways to reduce by-catch and capture of small fish. The outcomes of gear modification may depend on competition with other gears using similar fishing grounds and resources and the subsequent adoption or defection of fishers using modified gears. We evaluated the adoption, size, catch-per-unit-effort (CPUE), yield, and income responses among gears in a coral reef fishery where a 3-cm escape gap was introduced into traditional traps. The size of fish increased in the modified traps but the catch of smaller fish increased among the other competing gears. Additionally, there was no change in the overall CPUE, yields, or per area incomes but rather redistributions of yield benefits towards the competing gears. For example, estimated incomes of fishers that adopted the traps remained unchanged but increased for net and spear fishers. Fishers using escape-gap traps had a high proportion of income from larger fish, which may have led to a perception of benefits, high status, and no defections. The less polarizing neutral-win rather than a strong loss-win tradeoff outcome may explain the full adoption of escape-gap traps 3 years after their introduction. Trap fishers showed an interest in negotiating other management improvements, such as increased mesh sizes for nets, which could ultimately lead to catalyzing community-level decisions that would increase their own profits.
A substantial amount of scientific effort goes into understanding and measuring compliance in fisheries. Understanding why, how and when fishers follow or violate rules is crucial for designing effective fishery policies that can halt overfishing. Non-compliance was initially explained almost exclusively with reference to economic and self-interested motivations. More recently, however, most explanations involve a combination of economic, social, political and environmental factors. Despite this recent development towards more holistic explanations, many scientists continue to frame the issue in binary terms: fishers either follow rules, or they don't. In this article we challenge this binary interpretation and focus attention on the diversity of fishers’ dispositions and perceptions that underpin compliant behaviour. To this aim we construct a typology of fishers’ responses towards regulation and authorities, thereby developing conceptual tools to understand different motivations and attitudes that underlie compliance outcomes. For this purpose, we identify the motivational postures of ‘creativity’ and ‘reluctance’, and then highlight their empirical relevance with an interview study of Swedish fishers. Reasons for studying the quality and diversity of fishers’ motivations and responses are not purely academic. Conceptualizing and observing the quality of compliance can help policymakers and managers gauge and anticipate the potentiality of non-compliant fishing practices that may threaten the resilience of marine ecosystems.
It is well-known that operating within the boundaries of a national park provides commercial actors with the opportunity to charge a price premium, though this has to a lesser degree been demonstrated for marine protected areas. We estimate national tourists' willingness-to-pay a price premium for boat trips in the Nha Trang Bay Marine Protected Are, Vietnam, using a discrete choice experiment. Our results show that tourists are willing to pay an average price premium of 18 USD per trip for a large improvement in environmental quality, and that avoiding the loss of jobs for local fishermen is of minor importance. Furthermore, the economic benefits generated from management scenarios that combine biodiversity restoration and environmental quality improvement within the reserve sufficient to cover additional costs of such improvements.
On 23 September 2016, a workshop entitled “Innovating for change in global fisheries governance” was held in Tromsø, hosted by the K. G. Jebsen Centre for the Law of the Sea (JCLOS) at the Faculty of Law of UiT, The Arctic University of Norway. The aim of the workshop was to address the following question: How can international law be used as an innovative mechanism for change in global fisheries governance? Seven of the papers presented at the workshop, each one addressing a particular aspect of this overarching question, are published here in this special issue of Marine Policy.
•Examines moral economies of commercial and recreational fishers.
•Moral economy discourses stem from material interactions with fishery resources and historical development patterns.
•Fishers have divergent definitions of value, waste, and public resources.
•Fisher moral economies have the potential to be encoded in fisheries policies, affecting material access to resources.
Fish discards represent a large share of harvested biomass in shrimp fisheries. The aim of this paper is to propose a methodology for valuing discards of both commercial and non-commercial fish species discarded in the Gulf of California shrimp fishery, by estimating the monetary value of forgone fish biomass. The value of commercial fish species was carried out by using growth and population models, in order to simulate the biomass that, if left in the ocean instead of being harvested at Age 0, could reach an optimal fishing size. Using deflated ex-vessel prices, the present value of commercial species hypothetically harvested at an optimal age, was computed. The value of non-commercial fish species represented the forgone benefits of not using discarded biomass for producing fishmeal. Hence, the estimated value of fish diversity discarded in trawling operations in 2013 would range between USD 60.80 million and USD 103.4 million. This estimate is one of the first attempts to give an economic value to both commercial and non-commercial discarded fish biomass. Hopefully, the methodology here proposed will serve as inspiration for further research in economic valuation of marine biodiversity.
Global demand for energy and oil-based products is progressively introducing petrogenic polycyclic aromatic hydrocarbons (PAHs) into sensitive marine environments, primarily from fossil-fuel exploration, transport, and urban and industrial runoff. These toxic pollutants are found worldwide, yet the long-term ecological effects on coral reef ecosystems are unknown. Here, we demonstrate that oil exposure spanning PAH concentrations that are environmentally relevant for many coastal marine ecosystems (≤5.7 μg l−1), including parts of the Great Barrier Reef, Red Sea, Asia and the Caribbean, causes elevated mortality and stunted growth rates in six species of pre-settlement coral reef fishes, spanning two evolutionarily distinct families (Pomacentridae and Lethrinidae). Furthermore, oil exposure alters habitat settlement and antipredator behaviours, causing reduced sheltering, shoaling and increased risk taking, all of which exacerbate predator-induced mortality during recruitment. These results suggest a previously unknown path, whereby oil and PAH exposure impair higher-order cognitive processing and behaviours necessary for the successful settlement and survival of larval fishes. This emphasizes the risks associated with industrial activities within at-risk ecosystems.
Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after trawling. Depletion of biota and trawl penetration into the seabed are highly correlated. Otter trawls caused the least depletion, removing 6% of biota per pass and penetrating the seabed on average down to 2.4 cm, whereas hydraulic dredges caused the most depletion, removing 41% of biota and penetrating the seabed on average 16.1 cm. Median recovery times posttrawling (from 50 to 95% of unimpacted biomass) ranged between 1.9 and 6.4 y. By accounting for the effects of penetration depth, environmental variation, and uncertainty, the models explained much of the variability of depletion and recovery estimates from single studies. Coupled with large-scale, high-resolution maps of trawling frequency and habitat, our estimates of depletion and recovery rates enable the assessment of trawling impacts on unprecedented spatial scales.