Marine reserve design often considers potential benefits to conservation and/or fisheries but typically ignores potential revenues generated through tourism. Since tourism can be the main source of economic benefits for many marine reserves worldwide, ignoring tourism objectives in the design process might lead to sub-optimal outcomes. To incorporate tourism benefits into marine reserve design, we develop a bioeconomic model that tracks tourism and fisheries revenues through time for different management options and location characteristics. Results from the model show that accounting for tourism benefits will ultimately motivate greater ocean protection. Our findings demonstrate that marine reserves are part of the optimal economic solution even in situations with optimal fisheries management and low tourism value relative to fisheries. The extent of optimal protection depends on specific location characteristics, such as tourism potential and other local amenities, and the species recreational divers care about. Additionally, as tourism value increases, optimal reserve area also increases. Finally, we demonstrate how tradeoffs between the two services depend on location attributes and management of the fishery outside marine reserve borders. Understanding when unavoidable tradeoffs will arise helps identify those situations where communities must choose between competing interests.
Private industry, the Government of Gabon and two international NGOs collaborated to conduct marine surveys off the coast of Gabon, Central Africa. Surveys addressed multiple objectives of surveillance and monitoring, the documentation of the distribution of and threats to the marine megafauna, and capacity-building among government agents and local early-career scientists. During 22 days of survey effort over a two-year period, observers documented humpback whales Megaptera novaeangliae, bottlenose dolphins Tursiops truncatus, Atlantic humpback dolphins Sousa teuszii and common dolphins Delphinus delphis. Humpback whale presence was limited to the months of July to November. Bottlenose dolphins were present year-round and photo-identification of individuals indicated a closed, resident population, with an abundance estimate of 118 (CV = 21.6%, 95% CI 78–180). Small open-decked fishing vessels with gillnets were observed concentrated around river mouths within 2 km of shore, while commercial trawlers were at least 10 km offshore; all were confirmed to be registered and legal. Observations of marine turtles, flocks of marine birds, and floating logs and other debris were sparse. This multi-stakeholder collaboration to conduct a marine survey can serve as an effective model by which funding and logistic support from private industry paired with technical expertise from NGOs and academic institutions can benefit marine and coastal conservation.
Marine reserves are widely used to protect species important for conservation and fisheries and to help maintain ecological processes that sustain their populations, including recruitment and dispersal. Achieving these goals requires well-connected networks of marine reserves that maximize larval connectivity, thus allowing exchanges between populations and recolonization after local disturbances. However, global warming can disrupt connectivity by shortening potential dispersal pathways through changes in larval physiology. These changes can compromise the performance of marine reserve networks, thus requiring adjusting their design to account for ocean warming. To date, empirical approaches to marine prioritization have not considered larval connectivity as affected by global warming. Here, we develop a framework for designing marine reserve networks that integrates graph theory and changes in larval connectivity due to potential reductions in planktonic larval duration (PLD) associated with ocean warming, given current socioeconomic constraints. Using the Gulf of California as case study, we assess the benefits and costs of adjusting networks to account for connectivity, with and without ocean warming. We compare reserve networks designed to achieve representation of species and ecosystems with networks designed to also maximize connectivity under current and future ocean-warming scenarios. Our results indicate that current larval connectivity could be reduced significantly under ocean warming because of shortened PLDs. Given the potential changes in connectivity, we show that our graph-theoretical approach based on centrality (eigenvector and distance-weighted fragmentation) of habitat patches can help design better-connected marine reserve networks for the future with equivalent costs. We found that maintaining dispersal connectivity incidentally through representation-only reserve design is unlikely, particularly in regions with strong asymmetric patterns of dispersal connectivity. Our results support previous studies suggesting that, given potential reductions in PLD due to ocean warming, future marine reserve networks would require more and/or larger reserves in closer proximity to maintain larval connectivity.
Coastal systems are constantly in flux, and feedback from monitoring is necessary to support decision making for effective sustainable natural resource management. Frequently natural resources are the ultimate target of management actions, but management programs work through the proximate step of regulating human behavior towards those resources. For example, a marine reserve is considered a conservation success when the abundance and diversity of organisms increase within reserve boundaries, all relative to existing trends that would have affected ecological communities in the absence of a reserve. Biological monitoring can assesses whether reserve management achieves these goals. However, when monitoring data are inconclusive or do not match expectations, managers face uncertainty in understanding why particular biological patterns occurred, whether a reserve is a biologically appropriate management strategy for the system, and what steps to take moving forward. Monitoring human behavior can provide information that may alleviate some uncertainty and help explain observed biological patterns. In this study we illustrate the utility of complimenting biological monitoring data with monitoring of human behavior. We used a before-after control-impact analysis to test for effects of a no-take reserve in the Gulf of California, Mexico on the density and biomass of seven fished species. We failed to detect a positive biological effect of the reserve, and found the density of five monitored species had declined. These results indicated that the reserve was not succeeding, but provided no insight into why. Evaluation of recreational angler use of the reserve provided a possible explanation: first, the frequency of angler visits to the study area was increasing over time. Second, the reserve reduced the propensity of anglers to visit the reserve, but not by enough to offset the overall increasing visitation trend. Biological and human use monitoring results in tandem indicated that a reserve could potentially be an effective conservation tool for the system, and allowed us to suggest modifications that could help the reserve succeed. Our work illustrates the necessity of monitoring human use changes alongside biological responses to a reserve for a holistic portrait of reserve functioning, providing a concrete example of the importance of human behavioral aspects of marine reserve success.
Recreational SCUBA diving market is a rapidly developing industry, which during the last years focuses among others in the observation of marine fauna and flora. An innovative approach towards this direction is to study whether animal, and particularly fish behaviour, can contribute to the development of SCUBA diving tourism. The principal two axes of the current survey were the enhancement of SCUBA diving safety (via the promotion of swallow waters biocommunities) and the marine life protection (via environmental awareness). The two study areas are located in Chalkidiki peninsula (Greece, North Aegean Sea). The preliminary part of this study demonstrated a non significant difference between males and females regarding their age, their diving experience (training level and hours of diving) and their diving preferences (depth and type of sea bottom). Nesting and agonistic behavior of three Labridae fish (Symphodus ocellatus, Symphodus cinereus, Xyrichthys novacula) were used as motivation factors in the three testing hypotheses. Among those three hypotheses, diving in shallow rocky bottom aiming at the observation of Symphodus ocellatus seems to be the most attractive for the divers. As a general remark, briefing is a very useful tool that can inform, but also orientate the customers. Additionally, the very poor knowledge of Mediterranean undersea wildlife, especially by the recreational SCUBA diving staff should be mentioned. As a conclusion, the current approach can be used for the enhancement of SCUBA diving product (i.e. promotion of specialties such as Fish Identification) or increase of SCUBA diving equipment (i.e. underwater cameras).
The uneven petroleum distribution in the world and various countries’ dependence on the petroleum for economic development make maritime oil shipping an extremely important way for various countries to launch oil trade. Marine oil shipping, while bringing economic benefits to various countries, witnesses oil spill accidents by oil tankers, which led to losses to oil trading and shipping countries and seriously polluted the marine ecological environment. The tanker shipping pollution and oil spills’ damages to the marine environment have drawn much attention. This paper sets up an entropy weighted grey relation analysis method to analyze key contributors to oil spills, and evaluates the extent of impacts of each factor in different ship operations. Based on actual conditions of global oil tankers, we chose seven dominant contributors to global tanker oil spills for evaluation, and established an analytic framework of global tanker oil spill factors based on the combined method, with specific analysis steps and methods provided. Finally, we conducted a model empirical study based on history data of global tanker oil spills in the past 46 years from 1970 to 2015 to verify the practicability and effectiveness of the model established in this paper for analyzing global tanker oil spill factors. The results of this study are conducive for government departments and policy makers to take appropriate and effective strategies to manage and prevent global tanker oil spills.
The possible impacts of the European Commission’s proposed North Sea Multi-Annual Plan are evaluated in terms of its likely outcomes to achieve management objectives for fishing pressure, species’ biomass, fishery yield, the landed value of key species and ecosystem objectives. The method applies management strategy evaluation procedures that employ an ecosystem model of the North Sea and its fisheries as the operating model. Taking five key dimensions of the proposed plan, it identifies those areas that are key to its successful performance. Overwhelmingly, choices in the options for the implementation of regulatory measures on discarding practices outweigh the effects of options related to fishing within ranges associated with ‘pretty good yield’, the way that biomass conservation safeguard mechanisms are applied and the timeframe for achieving fishing mortality targets. The impact of safeguard options and ranges in fishing mortality become important only when stock biomass is close to its reference points. The fifth dimension–taking into account wider conservation and ecosystem objectives—reveals that discard policy has a big impact on conservation species, but also that the type of harvest control rule can play an important role in limiting risks to stocks by ‘applying the brakes’ early. The consequences to fisheries however is heightened risk to their viability, thus exposing the sustainability trade-offs faced with balancing societal pressures for blue growth and enhanced conservation. It also reveals the wider ecosystem impacts that emphasise the connectivity between the demersal and pelagic realms, and thus, the importance of not treating the demersal NSMAP in isolation from other management plans. When stocks are below their biomass reference points, low F strategies lead to better long term economic performance, but for stocks consistently above biomass reference points, high F strategies lead to higher long term value. Nephrops and whiting often show contradictory responses to the strategies because changes in their predators abundance affects their abundance and success of their fisheries.
Fisheries bycatch is a widespread and serious issue that leads to declines of many important and threatened marine species. However, documenting the distribution, abundance, population trends and threats to sparse populations of marine species is often beyond the capacity of developing countries because such work is complex, time consuming and often extremely expensive. We have developed a flexible tool to document spatial distribution and population trends for dugongs and other marine species in the form of an interview questionnaire supported by a structured data upload sheet and a comprehensive project manual. Recognising the effort invested in getting interviewers to remote locations, the questionnaire is comprehensive, but low cost. The questionnaire has already been deployed in 18 countries across the Indo-Pacific region. Project teams spent an average of USD 5,000 per country and obtained large data sets on dugong distribution, trends, catch and bycatch, and threat overlaps. Findings indicated that >50% of respondents had never seen dugongs and that 20% had seen a single dugong in their lifetimes despite living and fishing in areas of known or suspected dugong habitat, suggesting that dugongs occurred in low numbers. Only 3% of respondents had seen mother and calf pairs, indicative of low reproductive output. Dugong hunting was still common in several countries. Gillnets and hook and line were the most common fishing gears, with the greatest mortality caused by gillnets. The questionnaire has also been used to study manatees in the Caribbean, coastal cetaceans along the eastern Gulf of Thailand and western Peninsular Malaysia, and river dolphins in Peru. This questionnaire is a powerful tool for studying distribution and relative abundance for marine species and fishery pressures, and determining potential conservation hotspot areas. We provide the questionnaire and supporting documents for open-access use by the scientific and conservation communities.
The whale shark (Rhincodon typus) is an iconic and endangered species with a broad distribution spanning warm-temperate and tropical oceans. Effective conservation management of the species requires an understanding of the degree of genetic connectivity among populations, which is hampered by the need for sampling that involves invasive techniques. Here, the feasibility of minimally-invasive sampling was explored by isolating and sequencing whale shark DNA from a commensal or possibly parasitic copepod, Pandarus rhincodonicus that occurs on the skin of the host. We successfully recovered mitochondrial control region DNA sequences (~1,000 bp) of the host via DNA extraction and polymerase chain reaction from whole copepod specimens. DNA sequences obtained from multiple copepods collected from the same shark exhibited 100% sequence similarity, suggesting a persistent association of copepods with individual hosts. Newly-generated mitochondrial haplotypes of whale shark hosts derived from the copepods were included in an analysis of the genetic structure of the global population of whale sharks (644 sequences; 136 haplotypes). Our results supported those of previous studies and suggested limited genetic structuring across most of the species range, but the presence of a genetically unique and potentially isolated population in the Atlantic Ocean. Furthermore, we recovered the mitogenome and nuclear ribosomal genes of a whale shark using a shotgun sequencing approach on copepod tissue. The recovered mitogenome is the third mitogenome reported for the species and the first from the Mozambique population. Our invertebrate DNA (iDNA) approach could be used to better understand the population structure of whale sharks, particularly in the Atlantic Ocean, and also for genetic analyses of other elasmobranchs parasitized by pandarid copepods.
As plastic production increases, so to do the threats from plastic pollution. Microplastics (defined as plastics < 5mm) are a subset of marine debris about which we know less than we do of larger debris items, though they are potentially ubiquitous in the marine environment. To quantify the distribution and change in microplastic densities through time, we sampled sediment cores from an estuary in Tasmania, Australia. We hypothesized that the type, distribution and abundance of microplastics observed would be associated with increasing plastic production, coastal population growth, and proximity to urban water outflows and local hydrodynamics. Sediments ranging from the year 1744 to 2004 were sub-sampled from each core. We observed microplastics in every sample, with greater plastic frequencies found in the upper (more recent) sediments. This time trend of microplastic accumulation matched that of global plastic production and coastal population growth. We observed that fibers were the most abundant type of microplastic in our samples. These fibers were present in sediments that settled prior to the presence of plastics in the environment. We propose a simple statistical model to estimate the level of contamination in our samples. We suggest that the current trend in the literature suggesting very high loads of fibers, particularly in remote locations such as the deep seafloor, may be largely due to contamination.