A development of the ecological risk screening (ERS) technique, scale intensity and consequence analysis (SICA), is described and application to the varied fisheries and ecosystem off the southwest of England on behalf of an industry steering group (SG) is summarized. The purpose was to prioritize ecological risks systematically and consistently in relation to policy goals agreed by the SG. Scientists listed and advised on ecosystem components, their units (individual species, stocks, habitats, or communities) and attributes, as well as agents of change in the SW, their activities, and generalized effects relevant to the policy goals. A working group (WG) of fishers, fishery observers, technical advisors, and marine scientists paired each unit with the activity thought most likely to impact the most sensitive policy goal, then scored risk according to defined rules spatially, temporally, and as intensity and duration of effects. The geometric mean of the four scores, slightly adjusted for unscored factors if necessary, was the relative impact score (RIS). With this standardized method, the main aspects of risk were considered separately and independently, thereby assisting objective prioritization. Nineteen unit–activity pairs were listed as priority risks (RIS >3) in the SW region during a 2-d meeting that fully exploited the wide range of information and experience available at the WG. Socio-economics was not considered. The ERS for the SW was designed to be compatible with other similar ERSs that might be carried out for neighbouring marine regions. ERS can minimize extra monitoring needed for ecosystem management and, in principle, collaborating non-fishery agents of change could be included. By engaging all stakeholders in the setting of initial priorities for action and by assembling all available sources of information, ERS offers a useful starting point for holistic ecosystem management.
The North Sea brown shrimp fishery is currently regulated neither with quotas nor with effort management. The current paradigm of non-management was based on an analysis of the total predation by cod and whiting in relation to commercial catches for the period 1970–1995 and the estimated total dominance of natural mortality. However, since this period, the North Sea ecosystem has undergone pronounced changes with overfishing and climate change causing a substantial decline in predator stocks, namely cod and whiting. In addition, both predators have shifted their range of distribution causing a reduced overlap with brown shrimp. Here, we extend the previous assessment of brown shrimp predation for the years 1996–2011 using updated stock assessment and predator distribution data. For the first time, predation estimates are used together with commercial landings to partition independent estimates of total mortality into fishing and predation mortality. We demonstrate that the decline of key predators of brown shrimp in combination with a shift in the distributional range of the predators has caused a new situation, in which the fishery has become the main mortality source of adult brown shrimp (>50 mm). Average landings since 2000 have been ∼40% higher than in the 1980s and 1990s, indicating that humans have at least partly taken over the share previously taken by juvenile whiting and cod. We discuss that this situation is likely to continue, because three marine mammal species have built up a combined population of over 80 000 individuals, which hunt for potential brown shrimp predators mainly in the distribution area of brown shrimp. The application of two yield-per-recruit models of different complexity indicates potential growth overfishing of brown shrimp and reopens the discussion of management.
Coastal fisheries and sea cage aquaculture coexist along the coastal zone, and it has been suggested that wild fish feed on excess feed around farms. If this occurs, the condition of wild fish can increase and their lipid profile can become modified. However, the influence of fishfarming on coastal fisheries has not been described in detail. Four targeted species of different trophic gilds, Sardinella aurita, Caranx rhonchus, Mullus barbatus, and Pomatomus saltatrix were studied and the lipid profiles of individuals captured by coastal fisheries and around fish farms were compared. Results show that fish captured at farms showed increased levels of total lipids and/or the terrestrial fatty acids contained in feed pellets. Individuals with increased terrestrial fatty acid proportions were detected in the catch of small-scale artisanal fisheries but not among trawled fish. Consequently, this study demonstrates the influence of fishfarming on coastal fisheries through the exportation of excess feed in the shape of wild fish biomass.
Population structuring in the northern shrimp (Pandalus borealis) in the North Sea area (including Fladen and Skagerrak) was studied by microsatellite DNA analyses. Screening 20 sample locations in the open ocean and Skagerrak fjords for nine loci revealed low, but significant genetic heterogeneity. The spatial genetic structure among oceanic samples of Skagerrak and the eastern North Sea was weak and non-significant, consistent with the current management regime of one single stock. However, Skagerrak fjord samples generally displayed elevated levels of genetic differentiation, and significantly so in several pairwise comparisons with other fjords and oceanic samples. Although the Skagerrak fjord populations are of less economic value, some of them are regulated separately (e.g. the Gullmarsfjord) and local stocks may prove important to uphold genetic variability and biocomplexity in a changing environment.
Assessing artisanal fishing effort and catches in remote tropical coastal areas is a continuous challenge for fisheries data collection. This is the first spatio-temporal analysis of the large tidal weir (LTW) fishery operating on intertidal sand banks along the world’s longest mangrove coast, north Brazil. Airborne synthetic-aperture radar (SAR) images and aerial photos were integrated with field sampling to investigate catch and discard compositions of seven LTW during the main fishing season. LTW measurements on the SAR images were used to generate estimates on daily catch, wood extraction, and sand accumulation. In a coastal stretch of 67 km, 793 LTW were identified on SAR images from 2004, including 573 active LTW. The number of active LTW in Taperaçú Bay and Caeté Bay had increased from 87 in 1998 to 132 in 2004 (52% increase), and from 92 to 202 (106% increase), respectively. Sixty-five fish species from 24 families were captured in the LTW. Ariidae, Sciaenidae, Haemulidae, and Carangidae accounted for 45, 20, 10, and 7% of the total sampled catch weight of 3441 kg, respectively. The mean daily catch per LTW was 110 kg ± 9 SE. Total discards in outer estuarine LTW were >3 times higher than in inner estuarine LTW. All Aspredinidae, Belonidae, Tetraodontidae, and Trichiuridae, and >75% of Auchenipteridae, Clupeidae, Engraulidae, Ephippidae, Loricariidae, Scombridae, and Soleidae were discarded. The LTW fishery apparently practices balanced harvesting; however, the massive LTW increase suggests fishing effort reduction to moderate levels. Mangrove wood extraction for LTW construction (22 835 m3 or 855 390 trees) and sand accumulation (144 802 m3) likely have only local scale effects, negligible for the overall ecosystem dynamics. The study highlights the potential of SAR images for use in fisheries data collection and management of tropical coasts, emphasizing the need for integration with ground-truthing field studies.
Norwegian aquaculture has grown from its pioneering days in the 1970s to be a major industry. It is primarily based on culturing Atlantic salmon and rainbow trout and has the potential to influence the surrounding environment and wild populations. To evaluate these potential hazards, the Institute of Marine Research initiated a risk assessment of Norwegian salmon farming in 2011. This assessment has been repeated annually since. Here, we describe the background, methods and limitations of the risk assessment for the following hazards: genetic introgression of farmed salmon in wild populations, regulatory effects of salmon lice and viral diseases on wild salmonid populations, local and regional impact of nutrients and organic load. The main findings are as follows: (i) 21 of the 34 wild salmon populations investigated indicated moderate-to-high risk for genetic introgression from farmed escaped salmon. (ii) of 109 stations investigated along the Norwegian coast for salmon lice infection, 27 indicated moderate-to-high likelihood of mortality for salmon smolts while 67 stations indicated moderate-to-high mortality of wild sea trout. (iii) Viral disease outbreaks (pancreas disease, infectious pancreatic necrosis, heart and skeletal muscle inflammation, and cardiomyopathy syndrome) in Norwegian salmon farming suggest extensive release of viruses in many areas. However, screening of wild salmonids revealed low to very low prevalence of the causal viruses. (iv) From ∼500 yearly investigations of local organic loading under fish farms, only 2% of them displayed unacceptable conditions in 2013. The risk of eutrophication and organic load beyond the production area of the farm is considered low. Despite several limitations, especially limited monitoring data, this work represents one of the world’s first risk assessment of aquaculture. This has provided the Norwegian government with the basis upon which to take decisions for further development of the Norwegian aquaculture industry.
In recent years, about one-third of the cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) catches in Icelandic waters have been obtained with longline. Although longlining has been regarded as a conservation-oriented fishing method, a serious drawback of this fishing gear is the high catches of undersized fish. Our purpose was to locate areas where catches of undersized fish are high and consider if it may be feasible to close them permanently for longlining. Extensive length measurements used in the analysis were made by official inspectors on-board longliners during 2005–2013 in the main fishing area around Iceland. We found that the percentage of undersized cod (<55 cm total length) and haddock (<45 cm) in those samples decreased in relation to both depth and distance from shore. Our results suggest that permanent closures of large nearshore areas for longlining is a feasible option to reduce catch of undersized cod and haddock.
Indonesia is a biodiversity hotspot threatened with new introductions of marine species. As with many countries, Indonesia has a stratified shipping network of international ports linked to a large suite of domestic ports. We developed a hub and spoke network model to examine the risk associated with the secondary transfer of introduced marine species from the port hub of Tanjung Priok in Jakarta Bay to the 33 Indonesian provinces (including other ports in the Jakarta province). An 11-year shipping dataset was used (vessel next port of call records for maritime vessels that originated in Jakarta Bay and that remained in domestic waters) to derive a province ranking of vulnerability. Fifteen provinces represented almost 94% of the traffic frequency, with East Java and Jakarta provinces dominating. All urban provinces featured within the top seven highest frequency traffic provinces. Traffic patterns reflect an intra-coastal reliance on shipping, with traffic frequency decreasing with distance from Jakarta Bay. Provinces were regionalized into three categories (Lampung to East Java, Makassar Straits, and Malacca Straits) each with different vulnerabilities based on their values.
We evaluated two risk models (bioregion pathway and species-based exposure), with the aim to determine an effective strategy to implement marine biosecurity risk management in regions/countries where biological data are limited. We used the Port of Tanjung Priok, Jakarta Bay, Indonesia, as a case study to test both models. The bioregion pathway model illustrates that Tanjung Priok is highly connected to the East Asian Sea (∼91%), and the Northwest Pacific, Mediterranean, and Australia & New Zealand bioregions (“Very Low” risk), with other bioregions posing “Negligible” risk, highlighting the importance of understanding regional port linkages. The bioregion pathway model strength is grounded by using readily available shipping data; however, it does not classify species into threat categories but considers a larger number of species as an increasing threat. The species exposure model found that 51 species pose a theoretical risk (10 “Moderate”, 20 “High”, and 21 “Extreme” risks) to Tanjung Priok. These 51 species can be used as a “watch list” for this port. If biosecurity measures for this port were restricted to the outcomes of the bioregion pathway model only 4 of the 51 species highlighted by the species exposure model would have been captured. The species model was data intensive, requiring extensive species datasets and consequently may be unsuitable when data are limited.
As part of a large impact study in a wind farm (OWEZ) in the Dutch coastal zone, the effects of exclusion of bottom trawling on the benthic community were studied by comparison with nearby reference areas which were regularly fished. In addition to a standard boxcorer for common macrofauna, a Triple-D dredge was used to collect longer-lived, more sparsely distributed infauna and epifauna. Multivariate analysis did not reveal any difference between the assemblages in and outside OWEZ with respect to abundance, biomass, and production after a 5-year closure. The Shannon–Wiener diversity index pointed to a significantly higher diversity in OWEZ compared with some of the reference areas. A minority of the bivalve species assumed to be sensitive to trawling showed higher abundances (Spisula solida) or larger sizes (Tellina fabula, Ensis directus) in OWEZ than in some of the reference areas. In general, samples collected with the Triple-D showed more differences between areas than boxcore samples. No evidence was also found that the species composition in OWEZ relative to the reference areas had changed in the period between 1 (2007) and 5 (2011) years after closure. The change observed in all areas between 2007 and 2011 was mainly due to relatively small variations in species abundances. In conclusion, 5 years after the closure of OWEZ to fisheries, only subtle changes were measured in the local benthic community, i.e. a higher species diversity and an increased abundance and lengths of some bivalves. Depleted adult stocks, faunal patchiness, and a limited time for recovery (5 years) might explain that a significant recovery could not be found. The current study shows that designation of large-scale marine protected areas as planned for the North Sea will not automatically imply that restoration of benthic assemblages can be expected within a relatively short period of years.
The adoption of risk-based methodologies is considered essential for the successful implementation of an ecosystem approach to fisheries and broader aquatic management. To assist with these initiatives, one of the qualitative risk assessment methods adapted for fisheries management over a decade ago has been reviewed. This method was updated to ensure compliance with the revised international standards for risk management (ISO 31000) and to enable consideration of ecological, economic, social, and governance risks. The review also addressed the difficulties that have been encountered in stakeholder understanding of the underlying concepts and to increase the discipline in its application. The updates include simplifying the number of consequence and likelihood levels, adopting graphical techniques to represent different consequence levels, and discussing how changes in uncertainty can affect risk scores. Adopting an explicit “weight of evidence” approach has also assisted with determining which consequence scenarios are considered plausible and, where relevant, their specific likelihoods. The revised methods therefore incorporate the conceptual elements from a number of qualitative and quantitative approaches increasing their reliability and enabling a more seamless transition along this spectrum as more lines of evidence are collected. It is expected that with continued application of these methods, further refinements will be identified.
Greenland halibut in the Northeast Atlantic currently have two separate management units: the Northeast Arctic (NEA) stock and the West Nordic (WN) stock. The biological basis for this separation is weak, and while the NEA stock has a well-described nursery area in the waters around the Svalbard archipelago, no such major nursery area is known for the WN stock. To examine the linkages between these two stocks, a tagging experiment was conducted in the Svalbard nursery area, which is the only known large nursery area for Greenland halibut in the Northeast Atlantic. A total of 25 149 juvenile Greenland halibut were tagged and released in the period 2005–2008, and as of January 2014, there were 155 recaptures: 92% were caught more than 170 km from the tagging site, while 59% had travelled more than 1500 km. During the first 2 years after tagging, recaptures were reported only from the fishing grounds in the NEA management area. Subsequently, the number of recaptures decreased in the NEA management area, while recaptures were beginning to be reported from the WN management area, which by 2014 accounted for 61% of the total number of reported recaptures. It was concluded that the stocks in the two management areas for Greenland halibut in the Northeast Atlantic have a common nursery ground, and that a recruitment index based on data from the nursery around Svalbard would reflect possible recruitment to the stocks of both management units. The lack of recaptures on the Southeast Greenland shelf suggests a stock boundary west of Iceland. It is suggested to further explore the stock delineation in these areas and that future stock assessments should explore the potential advantage of using a combined assessment model for the two current management units.
Ecosystem-based management (EBM) is promoted as the solution for sustainable use. An ecosystem-wide assessment methodology is therefore required. In this paper, we present an approach to assess the risk to ecosystem components from human activities common to marine and coastal ecosystems. We build on: (i) a linkage framework that describes how human activities can impact the ecosystem through pressures, and (ii) a qualitative expert judgement assessment of impact chains describing the exposure and sensitivity of ecological components to those activities. Using case study examples applied at European regional sea scale, we evaluate the risk of an adverse ecological impact from current human activities to a suite of ecological components and, once impacted, the time required for recovery to pre-impact conditions should those activities subside. Grouping impact chains by sectors, pressure type, or ecological components enabled impact risks and recovery times to be identified, supporting resource managers in their efforts to prioritize threats for management, identify most at-risk components, and generate time frames for ecosystem recovery.
Understanding trawling impacts on the benthic ecosystem depends to a large extent on the ability to estimate trawling activity at the appropriate scale. Several studies have assessed trawling at fine spatial scales yearly, largely ignoring temporal patterns. In this study, we analysed these temporal patterns in beam trawl effort intensity at 90 stations of the Dutch continental shelf of the North Sea for a period of 10 years, at a fine temporal (weekly) and spatial (110 × 70 m) scale using Vessel Monitoring by Satellite (VMS) data. Our results show that trawling is aggregated in time and shows clear seasonality, related to the behavior of the fleet and migration patterns of the target fish species. The temporal patterns affect the overall impact on and the recovery of the benthic community, as is illustrated with a benthic population model. Our results imply that trawling impact studies using high-resolution data like VMS should take account of the possibility of temporal aggregation and seasonality in trawling to improve the assessment of the impact of trawling on the population dynamics of benthos.
Implementing marine ecosystem-based management at regional and small spatial scales is challenging due to the complexity of ecosystems, human activities, their interactions and multilayered governance. Ecological risk assessments (ERAs) of marine biodiversity are often used to prioirtise issues but only give broad guidance of how issues might be addressed in the form of strategies. However, at small and regional spatial scales marine natural resource managers have to make decisions within these strategies about how to manage specific interactions between human uses and ecological components. By using the transition between risk characterization and risk treatment in ERA for marine biodiversity tractable ways through the complexity can be found. This paper will argue that specific management and research actions relevant to smaller spatial scales can be developed by using the linkage between risk factors and risk treatment in ERA. Many risk factors require risk treatments that extend beyond the boundary of local agencies or sector responsibilities. The risk factor-treatment platform provides a practical way that these boundaries can be opened up by providing a scientifically based and transparent process to engage all actors who need to be involved in addressing the issues raised by an ERA. First, the principles of the mechanism will be described. Second, how the mechanism is constructed will be introduced using examples from an urban estuary. Application of the mechanism reveals three different types of risk factors (stressor, ecological, and knowledge gap) that can be used to develop specific management and research actions to treat risks. The systematic approach enables the dual complexities of marine ecosystems and multiple human pressures to be unravelled to identify and target issues effectively. The risk factor treatment linkage provides a platform to negotiate and develop effective management and research actions across jurisdictional, disciplinary, community and stakeholder boundaries.
Marine protected areas (MPAs) are increasingly used to address multiple marine management needs, and the incorporation of stakeholders into the MPA planning and designation processes is considered vital for success. Commercial fishers are often the stakeholder group most directly affected by spatial restrictions associated with MPAs, and the success of MPAs often depends, at least in part, on the behaviours and attitudes of fishers. MPA planning processes that incorporate fishers, and minimize the negative impact of MPA designation on the fishing community, should therefore have a greater chance of success. Here, the incorporation of both quantitative and qualitative fisher-derived data in MPA planning is investigated using strategic conservation planning software and multi-scenario analysis. We demonstrate the use of spatial access priority data as a cost layer, and suggest a process for incorporating fishers' MPA suggestions into planning scenarios in a transparent, but flexible, way. Results show that incorporating fisher-derived data, both quantitative and qualitative, can significantly reduce the cost of MPA planning solutions: enabling the development of MPA network designs that meet conservation targets with less detrimental impact to fishing community. Incorporating fishers and fisher-derived data in MPA planning processes can improve both the efficiency and defensibility of planning outcomes, as well as contribute to reducing potential conflicts between biodiversity conservation and the fishing industry.
- Well-designed marine protected area (MPA) networks can deliver a range of ecological, economic and social benefits, and so a great deal of research has focused on developing spatial conservation prioritization tools to help identify important areas.
- However, whilst these software tools are designed to identify MPA networks that both represent biodiversity and minimize impacts on stakeholders, they do not consider complex ecological processes. Thus, it is difficult to determine the impacts that proposed MPAs could have on marine ecosystem health, fisheries and fisheries sustainability.
- Using the eastern English Channel as a case study, this paper explores an approach to address these issues by identifying a series of MPA networks using the Marxan and Marxan with Zones conservation planning software and linking them with a spatially explicit ecosystem model developed in Ecopath with Ecosim. We then use these to investigate potential trade-offs associated with adopting different MPA management strategies.
- Limited-take MPAs, which restrict the use of some fishing gears, could have positive benefits for conservation and fisheries in the eastern English Channel, even though they generally receive far less attention in research on MPA network design.
- Our findings, however, also clearly indicate that no-take MPAs should form an integral component of proposed MPA networks in the eastern English Channel, as they not only result in substantial increases in ecosystem biomass, fisheries catches and the biomass of commercially valuable target species, but are fundamental to maintaining the sustainability of the fisheries.
- Synthesis and applications. Using the existing software tools Marxan with Zones and Ecopath with Ecosim in combination provides a powerful policy-screening approach. This could help inform marine spatial planning by identifying potential conflicts and by designing new regulations that better balance conservation objectives and stakeholder interests. In addition, it highlights that appropriate combinations of no-take and limited-take marine protected areas might be the most effective when making trade-offs between long-term ecological benefits and short-term political acceptability.
Coral reefs are in rapid decline on a global scale due to human activities and a changing climate. Shallow water reefs depend on the obligatory symbiosis between the habitat forming coral host and its algal symbiont from the genus Symbiodinium (zooxanthellae). This association is highly sensitive to thermal perturbations and temperatures as little as 1°C above the average summer maxima can cause the breakdown of this symbiosis, termed coral bleaching. Predicting the capacity of corals to survive the expected increase in seawater temperatures depends strongly on our understanding of the thermal tolerance of the symbiotic algae. Here we use molecular phylogenetic analysis of four genetic markers to describe Symbiodinium thermophilum, sp. nov. from the Persian/Arabian Gulf, a thermally tolerant coral symbiont. Phylogenetic inference using the non-coding region of the chloroplast psbA gene resolves S. thermophilum as a monophyletic lineage with large genetic distances from any other ITS2 C3 type found outside the Gulf. Through the characterisation of Symbiodinium associations of 6 species (5 genera) of Gulf corals, we demonstrate that S. thermophilum is the prevalent symbiont all year round in the world's hottest sea, the southern Persian/Arabian Gulf.
Here we discuss how different life history strategies may affect the feasibility of achieving the three requirements for effective long-term conservation (self-seeding, connectivity, and protection). While sedentary organisms with a pelagic larval phase (most reef fishes and invertebrates), readily achieve this trinity (Planes et al., 2009), animals where dispersal only occurs as adults inevitably fail to meet all three requirements simultaneously (Figure 1). Here we propose a potential solution focusing on incorporating information on how habitat shapes adult dispersal to increase connectivity within networks of MPAs.
The implementation of effective no-take marine reserves or marine protected areas (MPAs) is a central goal of modern fisheries science. Accordingly, a number of studies have been conducted to understand broad rules for the creation of MPAs and have tested the effects of marine reserves for specific regions of interest. However, there still exist many challenges for implementing effective MPAs. Deducing theoretical conditions guaranteeing that the introduction of MPAs will increase fishing yields in age-structured population dynamics is one such challenge. To derive such conditions, a simple mathematical model is developed that follows the metapopulation dynamics of a sedentary species. The obtained results suggest that moderate recruitment success of an individual's eggs is a necessary condition for an MPA plan to increase biomass yields. Furthermore, numerical simulations of the optimal fishing regime with MPAs aiming at maximizing the fishing yields suggest that biomass yields monotonically decrease with the fraction of the MPAs. The optimal fishing mortality rate suddenly jumps to a very high value, leading to a sudden decline in the population biomass, to a lower level than in a fishing regime with a constant fishing mortality rate. The decline in the population biomass is never observed in the fishing regime with a constant fishing mortality.