The giant bumphead parrotfish (Bolbometopon muricatum) has experienced precipitous population declines throughout its range due to its importance as a highly-prized fishery target and cultural resource. Because of its diet, Bolbometopon may serve as a keystone species on Indo-Pacific coral reefs, yet comprehensive descriptions of its reproductive ecology do not exist. We used a variety of underwater visual census (UVC) methods to study an intact population of Bolbometopon at Wake Atoll, a remote and protected coral atoll in the west Pacific. Key observations include spawning activities in the morning around the full and last quarter moon, with possible spawning extending to the new moon. We observed peaks in aggregation size just prior to and following the full and last quarter moon, respectively, and observed a distinct break in spawning at the site that persisted for four days; individuals returned to the aggregation site one day prior to the last quarter moon and resumed spawning the following day. The mating system was lek-based, characterized by early male arrival at the spawning site followed by vigorous defense (including head-butting between large males) of small territories. These territories were apparently used to attract females that arrived later in large schools, causing substantial changes in the sex ratio on the aggregation site at any given time during the morning spawning period. Aggression between males and courtship of females led to pair spawning within the upper water column. Mating interference was not witnessed but we noted instances suggesting that sperm competition might occur. Densities of Bolbometopon on the aggregation site averaged 10.07(±3.24 SE) fish per hectare (ha) with maximum densities of 51.5 fish per ha. By comparing our observations to the results of biennial surveys conducted by the National Oceanic and Atmospheric Administration (NOAA) Coral Reef Ecosystem Division (CRED), we confirmed spatial consistency of the aggregation across years as well as a temporal break in spawning activity and aggregation that occurred during the lunar phase. We estimated the area encompassed by the spawning aggregation to be 0.72 ha, suggesting that spawning site closures and temporal closures centered around the full to the new moon might form one component of a management and conservation plan for this species. Our study of the mating system and spawning aggregation behavior of Bolbometopon from the protected, relatively pristine population at Wake Atoll provides crucial baselines of population density, sex ratio composition, and productivity of a spawning aggregation site from an oceanic atoll. Such information is key for conservation efforts and provides a basic platform for the design of marine protected areas for this threatened iconic coral reef fish, as well as for species with similar ecological and life history characteristics.
While coral reefs are increasingly threatened worldwide, they are also increasingly used for recreational activities. Given the environmental and socio-economic significance of coral reefs, understanding the links between human activities and coral health and evaluating the efficacy of marine protected areas (MPAs) as a management regime to prevent further deterioration are critically important. The aim of this study was to quantify indicators of coral health at sites inside and outside a newly rezoned MPA framework in the dive tourism hotspot of Koh Tao, Thailand. We found that patterns in the health and diversity of coral communities one year on did not reflect the protected status conferred by newly zoned MPAs, but instead reflected past history of recreational use around the island. Sites characterised as past high-use sites had lower mean percent cover of hard corals overall and of corals in the typically disease- and disturbance-susceptible family Acroporidae, but higher mean cover of species in the more weedy family Agariciidae. Past high use sites also had higher mean prevalence of infectious diseases and other indicators of compromised health. Sites within the newly established MPAs are currently subjected to higher levels of environmental and anthropogenic pressures, with sedimentation, algal overgrowth, feeding scars from Drupella snails, and breakage particularly prevalent compared to sites in non-MPA areas. Given the greater prevalence of these factors within protected sites, the capacity of the MPA framework to effectively prevent further deterioration of Koh Tao's reefs is unclear. Nevertheless, our study constitutes a strong baseline for future long-term evaluations of the potential of MPAs to maintain coral health and diversity on highly threatened reefs.
Describes NOAA’s efforts to support the scientific, policy, and economic framework needed to increase use of information on coastal wetland’s carbon sequestration potential in coastal management.
Many scientific diagnoses of declining marine species and habitats and of recreational use patterns along U.S. coasts point to upland and freshwater sources of imperilment. A growing number of scientists argue that the best hope for protecting marine resources for multiple uses is to consider larger-scale processes, including activities that take place on land, when designing management strategies. But how inclusion of land- and water-use practices in strategies to sustain coastal marine resources affects management outcomes is poorly understood. The goal of this research is to assess the importance of including these practices in the management of coastal marine resources, using an ecosystem services framework. An ecosystem services framework provides a clear and novel path forward—one that integrates ecological processes with socioeconomic behavior and values.
The specific objectives of the research are to develop a set of linked watershed-marine models with ecosystem service outputs to evaluate management strategies for coastal resources and to apply those models to three case studies: Puget Sound, Galveston Bay, and Chesapeake Bay. In each case, we compare the strength and influence of watershed activities on key ecosystem services and ask how outcomes of marine resource management strategies are affected by including coastal watershed processes. We also explore a limited set of climate change scenarios. We estimate ecosystem services and their values using production function approaches, focusing on how changes in system function driven by land use management and climate change lead to changes in the provisioning of food from selected fisheries. Future work may extend this analysis to aquaculture, recreation, and coastal protection.
Industrial tuna fisheries operate in the Indian, Atlantic and Pacific Oceans, but concerns over sustainability and environmental impacts of these fisheries have resulted in increased scrutiny of how they are managed. An important but often overlooked factor in the success or failure of tuna fisheries management is the behaviour of fishers and fishing fleets. Uncertainty in how a fishing fleet will respond to management or other influences can be reduced by anticipating fleet behaviour, although to date there has been little research directed at understanding and anticipating the human dimension of tuna fisheries. The aim of this study was to address gaps in knowledge of the behaviour of tuna fleets, using the Indian Ocean tropical tuna purse seine fishery as a case study. We use statistical modelling to examine the factors that influence the spatial behaviour of the purse seine fleet at broad spatiotemporal scales. This analysis reveals very high consistency between years in the use of seasonal fishing grounds by the fleet, as well as a forcing influence of biophysical ocean conditions on the distribution of fishing effort. These findings suggest strong inertia in the spatial behaviour of the fleet, which has important implications for predicting the response of the fleet to natural events or management measures (e.g., spatial closures).
Ballast water in ships is an important contributor to the secondary spread of invasive species in the Laurentian Great Lakes. Here, we use a model previously created to determine the role ballast water management has played in the secondary spread of viral hemorrhagic septicemia virus (VHSV) to identify the future spread of one current and two potential invasive species in the Great Lakes, the Eurasian Ruffe (Gymnocephalus cernuus), killer shrimp (Dikerogammarus villosus), and golden mussel (Limnoperna fortunei), respectively. Model predictions for Eurasian Ruffe have been used to direct surveillance efforts within the Great Lakes and DNA evidence of ruffe presence was recently reported from one of three high risk port localities identified by our model. Predictions made for killer shrimp and golden mussel suggest that these two species have the potential to become rapidly widespread if introduced to the Great Lakes, reinforcing the need for proactive ballast water management. The model used here is flexible enough to be applied to any species capable of being spread by ballast water in marine or freshwater ecosystems.
A clear understanding of population structure is essential for assessing conservation status and implementing management strategies. A small, non-migratory population of humpback whales in the Arabian Sea is classified as “Endangered” on the IUCN Red List of Threatened Species, an assessment constrained by a lack of data, including limited understanding of its relationship to other populations. We analysed 11 microsatellite markers and mitochondrial DNA sequences extracted from 67 Arabian Sea humpback whale tissue samples and compared them to equivalent datasets from the Southern Hemisphere and North Pacific. Results show that the Arabian Sea population is highly distinct; estimates of gene flow and divergence times suggest a Southern Indian Ocean origin but indicate that it has been isolated for approximately 70,000 years, remarkable for a species that is typically highly migratory. Genetic diversity values are significantly lower than those obtained for Southern Hemisphere populations and signatures of ancient and recent genetic bottlenecks were identified. Our findings suggest this is the world's most isolated humpback whale population, which, when combined with low population abundance estimates and anthropogenic threats, raises concern for its survival. We recommend an amendment of the status of the population to “Critically Endangered” on the IUCN Red List.
We fish too much, and by doing so, we threaten marine ecosystems and people’s livelihoods. But the curious thing is: we have known this for a long time. Nonetheless, we continue to overfish. How is that possible? Why can we not stop? This paper recounts our search for an answer. We start by giving an overview of how scientists explain overfishing, and suggest that the riddle of its obduracy has not been addressed systematically. We conceptualize overfishing as an unplanned and unintended outcome of a chain of interrelated social and ecological events. We then analyze the chain of events leading to overfishing for two typical cases – the groundfish fishery in the Gulf of Maine and the South African abalone (Haliotis midae, Haliotidae) fishery – and two atypical cases where overfishing has stopped or been substantially reduced – the Patagonian and Antarctic toothfish (Dissostichus eleginoides, Nototheniidae and Dissostichus mawsoni, Nototheniidae) fishery in the Southern Ocean, and the Atlantic cod (Gadus morhua, Gadidae) fishery in the Barents Sea. Studying and comparing these cases reveals no sufficient set of factors to explain the persistence of overfishing. Rather, distinct pathways emerge from a concatenation of proximate and remote factors, leading to and sustaining overfishing. Understanding these pathways and their mechanisms can assist in locating leverage points for intervention aimed to stop overfishing.
Assuming a broad set of fisheries management goals, this paper analyzes the implementation of a marine protected area (MPA) together with open access outside, applying a bioeconomic model that ensures unchanged growth post-MPA. Taking into account that conservation and restoration, food security, employment and social surplus are amongst the objectives that many managers include in fisheries management, it is found that this broader welfare economic approach to MPAs may well recommend them to a greater degree than espoused in the more common resource rent focused studies carried out to date. It is shown that for overfished stocks, an MPA may yield resource protection, maximize harvests and increase consumer and producer surplus, as well as give higher employment. This, however, is less apparent for moderately overfished as well as highly migratory stocks. Resource protection and enhancement implicitly improves ecosystem services.
he mean trophic level of the farmed fish species in the Mediterranean has been increasing. We examined the farming-up hypothesis (i.e., the increase in the production of high-trophic-level species) in the Mediterranean by determining the trophic level of the aquafeeds (i.e., what the fish are fed) of 5 species of farmed marine fishes: common dentex (Dentex dentex), common pandora (Pagellus erythrinus), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and red porgy (Pagrus sp.). The mean trophic level of aquafeed used in mariculture from 1950 to 2011 was higher (3.93) than the prey farmed fish consume in the wild (3.72) and increased at a faster rate (0.48/decade) compared with that based on their diets in the wild (0.43/decade). Future expected replacement of the fishmeal and oil in aquafeeds by plant materials may reverse the farming-up trend, although there are a number of concerns regarding operational, nutritional, environmental, and economic issues. The farming-up reversal can be achieved in an ecologically friendly manner by facilitating the mariculture of low-trophic-level fishes and by promoting high efficiency in the use of living marine resources in aquafeeds.
Sharks are one of the most threatened groups of marine animals worldwide, mostly owing to overfishing and habitat degradation/loss. Although these cartilaginous fish have evolved to fill many ecological niches across a wide range of habitats, they have limited capability to rapidly adapt to human-induced changes in their environments. Contrary to global warming, ocean acidification was not considered as a direct climate-related threat to sharks. Here we show, for the first time, that an early ontogenetic acclimation process of a tropical shark (Chiloscyllium punctatum) to the projected scenarios of ocean acidification (ΔpH = 0.5) and warming (+4°C; 30°C) for 2100 elicited significant impairments on juvenile shark condition and survival. The mortality of shark embryos at the present-day thermal scenarios was 0% both at normocapnic and hypercapnic conditions. Yet routine metabolic rates (RMRs) were significantly affected by temperature, pH and embryonic stage. Immediately after hatching, the Fulton condition of juvenile bamboo sharks was significantly different in individuals that experienced future warming and hypercapnia; 30 days after hatching, survival rapidly declined in individuals experiencing both ocean warming and acidification (up to 44%). The RMR of juvenile sharks was also significantly affected by temperature and pH. The impact of low pH on ventilation rates was significant only under the higher thermal scenario. This study highlights the need of experimental-based risk assessments of sharks to climate change. In other words, it is critical to directly assess risk and vulnerability of sharks to ocean acidification and warming, and such effort can ultimately help managers and policy-makers to take proactive measures targeting most endangered species.
The MedMPAnet Project collaborated recently with MedPAN network and ACCOBAMS permanent secretariat in the publication of a new technical tool designed for MPA managers and dealing with the best practices for protecting cetaceans in the ACCOBAMS area.
The cetacean manual for MPA managers, published in October 2013, provides a comprehensive overview of the main cetaceans species regularly present in the ACCOBAMS area and reviews the following subjects:
- The monitoring of cetaceans populations in MPAs,
- The existing data and networks for cetaceans,
- The administrative and scientific guidelines to deal with dead and live stranding,
- The sustainable whale watching and volunteering activities,
- other socio-economic aspects.
While the impact of environmental forcing on recruitment variability in marine populations remains largely elusive, studies spanning large spatial areas and many stocks are able to identify patterns common to different regions and species. In this study, we investigate the effects of the environment on the residuals of a Ricker stock–recruitment (SR) model, used as a proxy of prerecruits' survival, of 18 assessed stocks in the Baltic and North Seas. A probabilistic principal components (PCs) analysis permits the identification of groups of stocks with shared variability in the prerecruits' survival, most notably a group of pelagics in the Baltic Sea and a group composed of gadoids and herring in the North Sea. The first two PCs generally grouped the stocks according to their localizations: the North Sea, the Kattegat–Western Baltic, and the Baltic Sea. This suggests the importance of the local environmental variability on the recruitment strength. Hence, the prerecruits' survival variability is studied according to geographically disaggregated and potentially impacting abiotic or biotic variables. Time series (1990–2009) of nine environmental variables consistent with the spawning locations and season for each stock were extracted from a physical–biogeochemical model to evaluate their ability to explain the survival of prerecruits. Environmental variables explained >70% of the survival variability for eight stocks. The variables water current, salinity, temperature, and biomass of other fish stocks are regularly significant in the models. This study shows the importance of the local environment on the dynamics of SR. The results provide evidence of the necessity of including environmental variables in stock assessment for a realistic and efficient management of fisheries.
Fisheries biology encompasses a tremendous diversity of research questions, methods, and models. Many sub-fields use observational or experimental data to make inference about biological characteristics that are not directly observed (called “latent states”), such as heritability of phenotypic traits, habitat suitability, and population densities to name a few. Latent states will generally cause model residuals to be correlated, violating the assumption of statistical independence made in many statistical modelling approaches. In this exposition, we argue that mixed-effect modelling (i) is an important and generic solution to non-independence caused by latent states; (ii) provides a unifying framework for disparate statistical methods such as time-series, spatial, and individual-based models; and (iii) is increasingly practical to implement and customize for problem-specific models. We proceed by summarizing the distinctions between fixed and random effects, reviewing a generic approach for parameter estimation, and distinguishing general categories of non-linear mixed-effect models. We then provide four worked examples, including state-space, spatial, individual-level variability, and quantitative genetics applications (with working code for each), while providing comparison with conventional fixed-effect implementations. We conclude by summarizing directions for future research in this important framework for modelling and statistical analysis in fisheries biology.
The dynamic nature of pelagic environments presents unique challenges for management. Despite the sharp increase in the number of marine protected areas (MPAs) with large pelagic areas, or pelagic marine protected areas (PMPAs), little literature exists regarding on-the-ground approaches to their management, in large part due to the relative newness of many large-scale PMPAs. Here we attempt to highlight pragmatic solutions or recommendations for the management challenges of PMPAs, particularly regarding setting objectives, monitoring and compliance, drawing from examples of existing PMPA management when possible. We suggest using techniques such as structured decision making and multi-criteria decision analysis for setting management objectives and actions and reducing conflict that will be inherent across the multi-agency, multi-objective landscape of PMPAs. We suggest cost-effective strategies for monitoring of complex pelagic interactions and far-ranging species, including tiers of monitoring importance linked to funding levels, and highlight means of determining when monitoring is a necessity. Finally, we highlight techniques to increase compliance within PMPAs, such as participatory monitoring. We focus on enforcement across the large scales of PMPAs, such as setting and effectively integrating biological and enforcement priorities, and implementing cost-effective enforcement, particularly in remote regions, using techniques such as international enforcement partnerships and enforcement technologies. Our goal is not to give a complete framework for PMPA management, but to collate existing lessons and provide a baseline for managers to build from, and to provide insight for scientists looking to focus research efforts to aid in management of protected pelagic ecosystems.
Ecosystem services are supplied by nature but, by definition, are received by people. Ecosystem service assessments, intended to influence the decisions people make regarding their interactions with nature, need to understand how people benefit from different ecosystem services. A critical question is therefore, What determines the distribution of ecosystem service benefits between different sections of society? Here, we use an entitlements approach to examine how people perceive ecosystem service benefits across 28 coral reef fishing communities in four countries. In doing so, we quantitatively show that bundles of benefits are mediated by key access mechanisms (e.g., rights-based, economic, knowledge, social, and institutional). We find that specific access mechanisms influence which ecosystem services people prioritize. Social, institutional, and knowledge mechanisms are associated with the largest number and diversity of benefits. However, local context strongly determines whether specific access mechanisms enable or constrain benefits. Local ecological knowledge enabled people to prioritize a habitat benefit in Kenya, but constrained people from prioritizing the same benefit in Madagascar. Ecosystem service assessments, and their resultant policies, need to include the broad suite of access mechanisms that enable different people to benefit from a supply of ecosystem services.
The interwoven nature of habitats and their acoustic fingerprints (soundscapes) is being increasingly recognized as a key component of animal ecology. Natural soundscapes are crucial for orientation in many different taxa when seeking suitable breeding grounds or settlement habitats. In the marine environment, coral reef noise is an important navigation cue for settling reef fish larvae and is thus a possible driver of reef population dynamics. We explored reef noise across a gradient of reef qualities, tested sound propagation models against field recordings and combined them with fish audiograms to demonstrate the importance of reef quality in determining which reefs larvae are likely to detect. We found that higher-quality reefs were significantly louder and richer in acoustic events (transient content) than degraded reefs, and observed that sound propagated farther with less attenuation than predicted by classic models. We discuss how zones of detection of poor-quality reefs could be reduced by over an order of magnitude compared to healthy reefs. The present study provides new perspectives on the far reaching effects habitat degradation may have on organisms that utilize soundscapes for orientation towards or away from coral reefs, and highlights the value of sound recordings as a cost-effective reef survey and monitoring tool.
Shifting political alliances and new environmental challenges are prompting debate over processes of sub-regionalisation and whether the interplay between multiple scales of governance leads to positive synergistic outcomes or negative institutional disruption. Regional management of tuna fisheries in the Western and Central Pacific Ocean is an example where a web of treaties, conventions and institutional frameworks underlie international cooperation. Through examining the interplay between the regional Western and Central Pacific Fisheries Commission and sub-regional Parties to the Nauru Agreement, this paper explores the extent to which the PNA and WCPFC interact in the management of regional tuna fisheries. The results demonstrate that for contested marine resources such as fisheries, international sub-regions can go beyond functional units to also present wider opportunities to shift power relations in favour of small island states. Additionally, the presence of sub-regional groups like the PNA has served to challenge the performance of the WCPFC, stimulating greater debate and progress within the regional body. The paper concludes that the combined work of the PNA and the WCPFC puts them ahead on many issues and may represent a testing ground for a functional multilateralism utilising both regional and sub-regional governance platforms for the management of shared resources.
Improved fisheries management provides fishers with more opportunities to maximize harvest value by accounting for valuable attributes of the harvest such as species, harvest timing, fish size, product form, and landing location. Harvest values can also vary by vessel and gear type. Moreover, the extent of targeting can influence the ecosystem in which the fishers operate and provide important management challenges. We utilize a unique dataset containing daily vessel-level fish landings in one region of Norway in 2010 to investigate the value of an array of attributes, including species, product form, product condition, timing, fish size, vessel type, gear type, and landing location for cod and other whitefish species, as well as king crab. We also investigate to what extent landed value differs across different communities, firms, and plants. The results indicate substantial variation for all attributes, highlighting opportunities for fishers as well as potential management challenges. For whitefish, the species landed accounts for three-quarters of the variation in prices. For cod in particular, the fish size accounts for nearly all variation in prices. In these fisheries, market conditions justify management focus on the biological composition of the catch.
Marine protected areas (MPAs) hold great promise as an effective conservation tool, but the potential negative socioeconomic impacts of MPAs remain poorly understood. Indeed, little work has been done to advance the frameworks and methods needed to assess, measure, and communicate the potential negative socioeconomic impact of MPAs and incorporate this information in MPA planning and management efforts. To address this gap, we test a vulnerability assessment termed the Livelihood Vulnerability Index (LVI) that is designed to measure the relative potential impact a proposed MPA network may have upon fisherman livelihoods. To test the LVI, specifically we ask, how does the vulnerability of fishermen to the impact of MPAs differ across place? We explore this question through two core areas of inquiry surrounding the study of vulnerability assessments: 1) Ranking and comparing vulnerability and 2) Explaining attributes of vulnerability. Through this study we demonstrate how the historical and current conditions fishermen experience in a given place shape vulnerability levels in various ways. Variability in the attributes of a particular place such as weather conditions, the size of fishing areas, availability of alternative fisheries, and changes in kelp cover contribute inherently as measures of vulnerability but they also shape fishermen perceptions of what are important measures of vulnerability. Secondly, counter to existing notions, the use of weights in vulnerability assessments may not significantly impact vulnerability scores and ranking. Together these findings emphasize the need to test vulnerability assessments against actual experienced impact or harm across geographies and groups of fishermen towards an informed refinement of vulnerability assessments. We emphasize that the particularities of place are critical to understand, to appropriately assess and thus to effectively mitigate vulnerability in order to promote the future well being of fisherman livelihoods.