A survey questionnaire designed to determine mariner knowledge and awareness of endangered whales, existing conservation measures, and mariner receptivity to near real-time conservation technology on the bridge is herein reported. The survey, distributed by the Shipping Federation of Canada, yielded 43 responses. The majority of respondents were interested in receiving information on endangered whales and conservation measures in eastern Canada and USA Gulf of Maine regions (72% and 79%, respectively). Eighty-four percent of respondents indicated a preference for receiving whale alerts via Navigational telex (NAVTEX) and 79% listed NAVTEX as the most “not disruptive” means of receiving the alerts. A similar 72% also listed Automatic Identification Systems (AIS) as “not disruptive”, and 58% identified AIS as the preferred reception format. The results show that the commercial fleet is moderately receptive to near real-time whale alerts on the bridge. It is concluded that to better understand mariner willingness to participate in whale conservation, researchers should consider defining the response required of mariners when receiving such alerts. The results also suggest that future conservation programs should use communication formats that are most familiar to, and favoured by, mariners while being the least disruptive to bridge protocols; i.e., NAVTEX and AIS.
Although a number of prospective locations for tidal stream farms have been identified, the development of a unified approach for selecting the optimum site in a region remains a current research topic. The objective of this work is to develop and apply a methodology for determining the most suitable sites for tidal stream farms, i.e. sites whose characteristics maximise power performance, minimise cost and avoid conflicts with competing uses of the marine space. Illustrated through a case study in the Bristol Channel, the method uses a validated hydrodynamics model to identify highly energetic areas and a geospatial Matlab-based program (designed ad hoc) to estimate the energy output that a tidal farm at the site with a given technology would have. This output is then used to obtain the spatial distribution of the levelised cost of energy and, on this basis, to preselect certain areas. Subsequently, potential conflicts with other functions of the marine space (e.g. fishing, shipping) are considered. The result is a selection of areas for tidal stream energy development based on a holistic approach, encompassing the relevant technical, economic and functional aspects. This methodology can lead to a significant improvement in the selection of tidal sites, thereby increasing the possibilities of project acceptance and development.
Residues of environmental contaminants in food represent a concern in food safety programs. In this study, the distribution of persistent organic pollutants (POPs) were evaluated in 79 tuna samples from FAO areas 51 (Indian Ocean), 71 (Pacific Ocean), 34 (Atlantic Ocean), and 37 (Mediterranean Sea). 6 polychlorinated biphenyls (PCBs), 16 organochlorines (OCs) and 7 polybrominated biphenyl ethers (PBDEs) were selected as representative compounds according to EFSA POPs monitoring guidelines. An analytical method, based on Accelerated Solvent Extraction (ASE), with an “in-line” clean-up step and GC-MS/MS detection, was developed, validated and applied. PCBs were detected in all FAO areas, with a prevalence of 100% for most of them. In the FAO area 37, only, all PBDEs were detected. Only 5 OCs were detected. The results showed that POPs contamination of tuna reflects FAO area contamination; in particular FAO area 37 was the most polluted. Moreover, tuna muscle was an appropriate matrix for monitoring contamination and for obtaining information about food safety.
Sediment cores from the central Beibu Gulf and its northern coastal mangroves were analyzed for polycyclic aromatic hydrocarbons (PAH), the organo-chlorine pesticides dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB), and polychlorinated biphenyls (PCB), to reconstruct the organic pollution history of developing south-west China. Reflecting regional development, in the gulf ∑PAH (38–74 ng g−1) decreased towards the surface after peak concentrations near 10 cm, while ∑DDT (ND – 0.5 ng g−1) increased due to fresh inputs, and HCB (ND – 0.04 ng g−1) occurred only in surface sediments. Profiles in mangrove sediments showed a continuing local scale increase in ∑PAH (29–438 ng g−1) as well as ∑DDT (0.2–41.0 ng g−1) and HCB (0.01–1.01 ng g−1) pollution, despite some variability. No trend was evident for ∑PCB (ND – 0.22 ng g−1), which was not detected in the central gulf. Calculated loads estimate that 2816 ng cm−2 PAHs and 7 ng cm−2 DDTs are stored in depositional areas of the Beibu Gulf. Mangrove sediments, threatened by land-use-change, contain 1400–4600 ng cm−2 PAHs and 34–39 ng cm−2 DDTs.
Imposex incidence and biometric parameters were investigated in six muricid species along of 1200 km of Ecuadorian shore and in Galapagos archipelago. The obtained data, were compared to previous studies performed in the same area in 2009. The results showed that moderate imposex levels still occur in coastal areas of Ecuador, even after global TBT ban. However, a reduction in imposex parameters was detected in the sampled sites, indicating probably relationship to the global TBT ban issued by IMO at 2008. On the other hand, the levels currently reported in present study indicates that TBT environmental concentrations are still high enough to produce biological effects in studied areas. In addition, imposex incidence in four muricid species from Galapagos islands were detected suggesting that this marine protected area is under threat of antifouling contamination. These findings, after TBT global ban, denotes that current regulations and conservation plans still need to address such an issue and incorporate more restrictive management rules, particularly in complex coastal areas, vulnerable and unique systems such as the Galapagos Islands.
This paper considers a team of spatially distributed drifters that move underwater under the influence of an ocean internal wave. The overall objective is for the drifters to use the known depth-dependent ocean flowfield to rendezvous underwater and then return to the surface as a cluster for easy retrieval. From the structure of the internal wave, the ocean flowfield is time-varying and spatially dependent on depth and position along the wave propagation direction. The drifters can control their depth by changing their buoyancy and are otherwise subject to the horizontal flowfield at their given depth. We consider two different drifter dynamical models: a first-order Lagrangian model, useful when the drifter’s mass is sufficiently small, and a second-order linear model, where the drag force caused by the water accelerates the drifter. We design provably correct distributed algorithms that rely on the drifters opportunistically changing their depth so that the ocean flowfield takes them in a desirable direction to perform coordinated motion. Under the proposed algorithms, the drifters converge asymptotically to the same depth and position along the wave propagation direction. We also investigate the algorithms’ robustness against errors in actuation, estimation of the wave parameters, or state measurements. Various simulations illustrate our results.
While there are persistent calls for developing more marine protected areas (MPAs) for Asian horseshoe crab conservation in response to population declines in Asia–Pacific region, most existing horseshoe crab MPAs were designated without prior comprehensive population assessment and habitat characterization. This study collected biological and habitat information in Hong Kong, in order to identify priority sites for conservation and management of Asian horseshoe crab populations. The territory-wide surveys at 18 spawning/nursery beaches displayed a persistently low mean juvenile density from 0.16 to 2.19 ind/100 m2 in 2012 and 0.08 to 1.41 ind/100 m2 in 2014. These density data were within the same range of that in 2002 and 2007 (0.10–1.97 ind/100 m2), apart from a low survey return of 0.08–0.31 ind/100 m2 in 2004. The current population of juvenile T. tridentatus and C. rotundicauda in Hong Kong is estimated about 2100–4300 and 2400–3000 individuals, respectively. From the 2012–2014 data, no new recruitments of 1st–3rd instar juveniles were found, as the shores were occupied mostly by 6th–9th instar juveniles of prosomal width between 23 and 45 mm, in which considerably high mortality rates were noted. The present findings of existing small and discrete juvenile populations, coupled with relatively few recruits, suggest that the status of juvenile horseshoe crabs in Hong Kong is fragile and vulnerable to local extirpation, especially if no urgent protection measures are implemented. Based on available population data and habitat characteristics, three MPAs, ranging from 5 to 7 km2, are proposed, so as to conserve over 60 and 70 % of the existing juvenile populations of T. tridentatusand C. rotundicauda, respectively. The approach adopted in this study may serve as a case study for proposing other horseshoe crab MPAs in Asia, where increasing human disturbances and over-harvest are imminent.
Conservation designations such as protected areas are increasing in numbers around the world, yet it is widely reported that many are failing to reach their objectives. They are frequently promoted as opportunities for win-win outcomes that can both protect biodiversity and lead to economic benefits for affected communities. This win-win view characterizes the dominant discourse surrounding many protected areas. Although this discourse and the arguments derived from it may lead to initial acceptance of conservation interventions, this study shows how it does not necessarily result in compliance and positive attitudes toward specific protected areas. Consequently, the discourse has important implications not just for making the case for protected area implementation, but also for the likelihood of protected areas reaching their objectives. We explain how the win-win discourse influences support for marine protected areas (MPAs) and, ultimately, their success. Using data from focus groups, questionnaires, and in-depth interviews at three MPA sites in the Philippines, we identified three reasons why the win-win discourse can negatively influence prolonged support for MPAs: dashed expectations, inequity, and temptation. Through an understanding of these issues, it becomes possible to suggest improvements that can be made pre-MPA implementation that can lead to prolonged support of MPAs. A focus on less tangible and economic MPA benefits, aligning MPA goals with cultural and social values, and higher levels of transparency when describing MPA outcomes are all ways in which prolonged support of MPAs can be bolstered.
The Santa Barbara Basin (SBB) fish assemblage over the last two millennia was examined using fish otoliths recovered from sediment cores. In Chapter 2, the hypothesis that otolith shape and elemental composition can be used to accurately discriminate between common southern California Current System fish taxa was tested. Digital images of 905 sagittal otoliths, representing 6 major taxonomic-based groups, were used to develop geometric (GEO) and elliptic Fourier (EF) shape measurements and a subset of 143 otoliths also analyzed for trace elements (ELM). Results indicate that random forest analysis was superior to discriminant function analysis and GEO features outperformed EF and ELM features for classification. Highest classification accuracy (96.3%) resulted from using the 10 strongest discriminatory features, which included a mixture of GEO, EF, and ELM features.
In Chapter 3, fossil otoliths (n = 1188) recovered from 3 Kasten and one box core sampled in the SBB were classified to taxonomic group by expert opinion (EO) and, after measuring shape and elemental features, by using the classification models developed in Chapter 2. Results of the EO and feature-based classification methods agreed strongly for the most abundant taxa and indicated that Myctophidae (52.7%) and Bathylagidae (31.5%) have dominated the forage fish assemblage in the SBB over the last two millennia. Less abundant taxa include Merlucciidae (6.9%), Sebastidae (4.8%), and Engraulidae (3.9%). Taxa displayed similar periods of variability on the decadal (50-90 years) and century scale (200 +/-50 years).
In Chapter 4, the relation of climate and SBB fish assemblage was investigated by comparing the otolith deposition rate (ODR) record with proxies of climate over the same period. Results indicate coherence between the ODR of Myctophidae, Bathylagidae, Engraulidae, and Sebastidae, which display significant correlation with temperature-based climate indices. The coherent pattern in several fish populations and basin-wide climate variability observed over off the coast of Southern California demonstrate the role of climatic forcing in regulating forage fish populations over the past two millennia. Our results provide baseline composition data and an increase understanding of natural variability of SBB fish populations.
Hydrodynamic connectivity describes the sources and destinations of water parcels within a domain over a given time. When combined with biological models, it can be a powerful concept to explain the patterns of constituent dispersal within marine ecosystems. However, providing connectivity metrics for a given domain is a three-dimensional problem: two dimensions in space to define the sources and destinations and a time dimension to evaluate connectivity at varying temporal scales. If the time scale of interest is not predefined, then a general approach is required to describe connectivity over different time scales. For this purpose, we have introduced the concept of a “retention clock” that highlights the change in connectivity through time. Using the example of connectivity between protected areas within Barnegat Bay, New Jersey, we show that a retention clock matrix is an informative tool for multitemporal analysis of connectivity.