One of the most important aspects of mathematical cognition in humans is the ability to symbolically represent magnitudes and quantities. In the last 20 years it has been shown that not only humans but also other primates, birds and dolphins can use symbolic representation of quantities. However, it remains unclear to what extent this ability is spread across the animal kingdom. Here, by training archerfish to associate variable amounts of rewards with different geometric shapes, we show for the first time that lower vertebrates can also associate a value with a symbol and make a decision that maximizes their food intake based on this information. In addition, the archerfish is able to understand up to four different quantities and organize them mentally in an ordinal manner, similar to observations in higher vertebrates. These findings point in the direction of the existence of an approximate magnitude system in fish.
The Deepwater Horizon (DWH) oil spill was by far the largest offshore oil spill in the history of the USA. For 87 d, the well spilled millions of barrels of oil into the Gulf of Mexico, extensively affecting the habitat of numerous species of cetaceans. Previous studies have suggested that cetaceans would be able to detect and avoid oiled waters and, when in contact, oil would not adhere to their slick skin. However, photographic evidence and field observations gathered following the DWH oil spill documented at least 11 cetacean species swimming through oil and sheen, with oil adhered to their skin. This study not only documented direct exposure of cetaceans to petroleum products but also the persistence of the oil on their skin. In addition, given the extent of the DWH oil spill, the number of affected species and individuals was likely far greater than the documented occurrences captured during this study. Based on this evidence, we suggest that during oil spills in cetacean habitat, direct exposure of whales and dolphins to petroleum products will likely occur and should therefore be taken into account during response activities and damage assessments.
Large whales are frequently entangled in fishing gear and sometimes swim while carrying gear for days to years. Entangled whales are subject to additional drag forces requiring increased thrust power and energy expenditure over time. To classify entanglement cases and aid potential disentanglement efforts, it is useful to know how long an entangled whale might survive, given the unique configurations of the gear they are towing. This study establishes an approach to predict drag forces on fishing gear that entangles whales, and applies this method to ten North Atlantic right whale cases to estimate the resulting increase in energy expenditure and the critical entanglement duration that could lead to death. Estimated gear drag ranged 11–275 N. Most entanglements were resolved before critical entanglement durations (mean ± SD 216 ± 260 days) were reached. These estimates can assist real-time development of disentanglement action plans and U.S. Federal Serious Injury assessments required for protected species.
In spite of their oceanic habitat, deep diving cetacean species have been found to be affected by anthropogenic activities, with potential population impacts of high intensity sounds generated by naval research and oil prospecting receiving the most attention. Improving the knowledge of the distribution and abundance of this poorly known group is an essential prerequisite to inform mitigation strategies seeking to minimize their spatial and temporal overlap with human activities. We provide for the first time abundance estimates for five deep diving cetacean species (sperm whale, long-finned pilot whale, northern bottlenose whale, Cuvier's beaked whale and Sowerby's beaked whale) using data from three dedicated cetacean sighting surveys that covered the oceanic and shelf waters of the North-East Atlantic. Density surface modelling was used to obtain model-based estimates of abundance and to explore the physical and biological characteristics of the habitat used by these species. Distribution of all species was found to be significantly related to depth, distance from the 2000m depth contour, the contour index (a measure of variability in the seabed) and sea surface temperature. Predicted distribution maps also suggest that there is little spatial overlap between these species. Our results represent the best abundance estimates for deep-diving whales in the North-East Atlantic, predict areas of high density during summer and constitute important baseline information to guide future risk assessments of human activities on these species, evaluate potential spatial and temporal trends and inform EU Directives and future conservation efforts.
Species targeted by fishing often recover in abundance and size within marine protected areas (MPAs) resulting in increased reproductive potential. However, in some situations, concomitant changes in the abundance of predators, competitors, or prey within MPAs, or strong gradients in the surrounding environmental seascape may counteract the purported benefits making it more difficult to predict how species will respond to protection. We used a network of MPAs in California, spanning a large temperature gradient, to investigate the drivers of demographic variability in the commercially important red sea urchin Mesocentrotus franciscanus. We investigated how demographic metrics varied geographically in response to protection, temperature, and the main sea urchin resource, the giant kelp Macrocystis pyrifera. We found significant conservation benefits to this fished sea urchin within MPAs designated six years prior to the beginning of this study. Within MPAs, red sea urchins were generally larger resulting in greater adult biomass density and reproductive biomass density. In addition, kelp density was an important explanatory variable of all red sea urchin demographic traits examined (adult size, gonadosomatic index [GSI], density, adult biomass density, and reproductive biomass density). Kelp density was positively correlated with red sea urchin GSI and adult size, but the relationships with density, adult biomass density, and reproductive biomass density were complex and the directionality changed depending on the region (or environmental setting) examined. Our results demonstrate that kelp, red sea urchin reproduction, and the effects of spatial management on demographic processes are tightly coupled with the oceanographic regime.
Given the limited resources available to address conservation problems, decision-makers are increasingly seeking management solutions that provide value for money. Despite an increasing number of studies that generate estimates of the return-on-investment from conservation management interventions, the ways in which costs are reported are highly variable and generally aggregated. This prevents comparison between studies and the application of systematic tools to synthesize conservation evidence and evaluate the factors that modify costs and benefits. A standardised consensus on the type of cost data to collect and report in conservation science would help build a body of evidence to support decision makers. In efforts to improve evidence-informed decision-making, conservation has looked to health care for tools to support the integration of evidence into management decisions. Increasingly, health care uses economic evaluations of treatment options to estimate the return-on-investment from medical interventions. Here, we describe economic evaluations as a tool for evidence-informed decision-making in health care and draw parallels for how these evaluations could be integrated into conservation. We also suggest tools to help systematically report economic costs of conservation interventions, and illustrate this approach with a case study of turtle conservation. We describe the important elements of economic evaluations, and how these data can be used to greatest effect through tools for evidence synthesis, such as systematic reviews or synopses, to enable decision-makers to identify cost-effective interventions. We believe that a routine commitment from researchers to capture the costs of management interventions would help support evidence-informed decision-making by facilitating the economic evaluations that support cost-effective management decisions. However, this will require clear guidelines for how to capture these data and incentives for conducting the necessary economic evaluations. Being able to present results systematically as return-on-investment could be an important step in encouraging greater use of science by those making management decisions.
The U.S. Northeast Continental Shelf marine ecosystem has warmed much faster than the global ocean and it is expected that this enhanced warming will continue through this century. Complex bathymetry and ocean circulation in this region have contributed to biases in global climate model simulations of the Shelf waters. Increasing the resolution of these models results in reductions in the bias of future climate change projections and indicates greater warming than suggested by coarse resolution climate projections. Here, we used a high-resolution global climate model and historical observations of species distributions from a trawl survey to examine changes in the future distribution of suitable thermal habitat for various demersal and pelagic species on the Shelf. Along the southern portion of the shelf (Mid-Atlantic Bight and Georges Bank), a projected 4.1 °C (surface) to 5.0 °C (bottom) warming of ocean temperature from current conditions results in a northward shift of the thermal habitat for the majority of species. While some southern species like butterfish and black sea bass are projected to have moderate losses in suitable thermal habitat, there are potentially significant increases for many species including summer flounder, striped bass, and Atlantic croaker. In the north, in the Gulf of Maine, a projected 3.7 °C (surface) to 3.9 °C (bottom) warming from current conditions results in substantial reductions in suitable thermal habitat such that species currently inhabiting this region may not remain in these waters under continued warming. We project a loss in suitable thermal habitat for key northern species including Acadian redfish, American plaice, Atlantic cod, haddock, and thorney skate, but potential gains for some species including spiny dogfish and American lobster. We illustrate how changes in suitable thermal habitat of important commercially fished species may impact local fishing communities and potentially impact major fishing ports along the U.S. Northeast Shelf. Given the complications of multiple drivers including species interactions and fishing pressure, it is difficult to predict exactly how species will shift. However, observations of species distribution shifts in the historical record under ocean warming suggest that temperature will play a primary role in influencing how species fare. Our results provide critical information on the potential for suitable thermal habitat on the U.S. Northeast Shelf for demersal species in the region, and may contribute to the development of ecosystem-based fisheries management strategies in response to climate change.
Economic incentives to harvest a species usually diminish as its abundance declines, because harvest costs increase. This prevents harvesting to extinction. A known exception can occur if consumer demand causes a declining species’ harvest price to rise faster than costs. This threat may affect rare and valuable species, such as large land mammals, sturgeons, and bluefin tunas. We analyze a similar but underappreciated threat, which arises when the geographic area (range) occupied by a species contracts as its abundance declines. Range contractions maintain the local densities of declining populations, which facilitates harvesting to extinction by preventing abundance declines from causing harvest costs to rise. Factors causing such range contractions include schooling, herding, or flocking behaviors—which, ironically, can be predator-avoidance adaptations; patchy environments; habitat loss; and climate change. We use a simple model to identify combinations of range contractions and price increases capable of causing extinction from profitable overharvesting, and we compare these to an empirical review. We find that some aquatic species that school or forage in patchy environments experience sufficiently severe range contractions as they decline to allow profitable harvesting to extinction even with little or no price increase; and some high-value declining aquatic species experience severe price increases. For terrestrial species, the data needed to evaluate our theory are scarce, but available evidence suggests that extinction-enabling range contractions may be common among declining mammals and birds. Thus, factors causing range contraction as abundance declines may pose unexpectedly large extinction risks to harvested species.
Is leaving headlands in fields unsprayed beneficial for wildlife?
Is paying farmers to cover the costs of bird conservation measures effective?
Is using prescribed fire beneficial for young trees in forests?
Does translocating frogs benefit wild populations?
Is providing artificial roost structures for bats beneficial?
What Works in Conservation has been created to provide practitioners with answers to these and many other questions about practical conservation. This book provides an assessment of the effectiveness of 763 conservation interventions based on summarized scientific evidence. Chapters cover the practical global conservation of amphibians, bats, birds and forests, conservation of European farmland biodiversity and some aspects of enhancing natural pest control, enhancing soil fertility and control of freshwater invasive species. It contains key results from the summarized evidence for each conservation intervention and an assessment of the effectiveness of each by international expert panels. The accompanying website www.conservationevidence.com describes each of the studies individually, and provides full references.
This is the second edition of What Works in Conservation, which is revised on an annual basis. It is also available as a free-to-download PDF at www.conservationevidence.com
Arcadia, Synchronicity Earth, ESRC, NERC, Natural England and Waitrose Ltd have generously contributed towards the publication of this volume.
Deep-sea areas characterized by the presence of polymetallic nodules are getting increased attention due to their potential commercial and strategic interest for metals such as nickel, copper, and cobalt. The polymetallic nodules occur in areas beyond national jurisdiction, regulated by the International Seabed Authority (ISA). Under exploration contracts, contractors have the obligation to determine the environmental baseline in the exploration areas. Despite a large number of scientific cruises to the central east Pacific Ocean, few published data on the macrofaunal biodiversity and community structure are available for the abyssal fields of the Clarion-Clipperton Fracture Zone (CCFZ). This study focused on the macrofaunal abundance, diversity, and community structure in three physically comparable, mineable sites located in the license area of Global Sea Mineral Resources N.V. (GSR), at ~4,500 m depth. A homogeneous but diverse macrofaunal community associated with the sediment from polymetallic nodule areas was observed at a scale of 10 to 100 s of km. However, slight differences in the abundance and diversity of Polychaeta between sites can be explained by a decline in the estimated flux of particulate organic carbon (POC) along a southeast-northwest gradient, as well as by small differences in sediment characteristics and nodule abundance. The observed homogeneity in the macrofaunal community is an important prerequisite for assigning areas for impact and preservation reference zones. However, a precautionary approach regarding mining activities is recommended, awaiting further research during the exploration phase on environmental factors structuring macrofaunal communities in the CCFZ. For instance, future studies should consider habitat heterogeneity, which was previously shown to structure macrofauna communities at larger spatial scales. Acknowledging the limited sampling in the current study, a large fraction (59–85%; depending on the richness estimator used and the macrofaunal taxon of interest) of the macrofaunal genus/species diversity from the habitat under study was characterized.
In ratifying the United Nations Framework Convention on Climate Change (UNFCCC), Trinidad and Tobago gave its commitment to contribute towards mitigating greenhouse gas emissions and instituting measures for adapting to climate change impacts. Formulation of a National Climate Change Policy subsequently took place with a view to providing direction towards fulfilling UNFCCC obligations.
The National Climate Change Policy identified that coastal areas of Trinidad and Tobago were particularly vulnerable to climate change impacts. As a small island State, the country cannot afford its productive sectors operating in and/or reliant upon coastal resources to be at risk, even as some contribute to the climate change phenomenon. The increasing threat to socio-cultural, economic and environmental sustainability posed by climate change, was acknowledged in the Draft National Integrated Coastal Zone Management (ICZM) Policy Framework which aims to treat with climate change impacts in the coastal zone and reduce vulnerability to associated hazards.
Given the stated objectives of the National Climate Change Policy and the Draft National ICZM Policy Framework, this paper examined the policy and plans in place to integrate climate change considerations into management for the coastal sectors of fisheries, energy, tourism and maritime transport. It found that the mainstreaming of climate change mitigation and adaptation responses in these coastal sectors has not been as effective as needed. Progress in this regard was constrained by human, financial and technical resource availability. Proposed are rationalised institutional arrangements which, if statutorily grounded, will better allow for achieving co-ordinated climate change mitigation and adaptation outcomes in Trinidad and Tobago.
The ecosystem services approach has increasingly emerged as a core requirement of ecosystem-based management of the marine space. In this context, explicit quantification and mapping of ecosystem services is considered key. This research proposes a methodological framework that combines Geographic Information Systems and participatory techniques to map the ecosystem service of recreation opportunities, provided by coastal and marine ecosystems. Attributes selected to represent the ecosystem service were scenic beauty, unique natural resources, accessibility, cultural sites and tourism use aptitude. High values of the indicator concentrated on areas that combined the presence of unique marine fauna (e.g. Southern Elephant Seal, Mirounga leonina), terrestrial and marine routs, and areas of high scenic beauty, associated to the presence of glaciers. These areas corresponded to the southern part of Almirantazgo Sound, the northern part of Navarino Island on the coast of the Beagle Channel, and to areas surrounding Wulaia fishermen's cove. Zones showing highest values of the indicator 81–100) comprised 0.89% of the study area and a small proportion of them coincided with areas of aptitude for aquaculture, which represents potential use conflicts, as long as aquaculture concessions remain operative. In turn, the areas of lowest values 0–20) were located offshore in open sea, and comprised 0.49% of the study area. Overall, the methodology demonstrated the capacity to identify potential recreation areas to inform regional decision making regarding marine use planning.
The paper develops and analyses a dynamic general equilibrium model with heterogeneous agents that can be used for assessment of the economic consequences of fish stock-rebuilding policies within the EU. In the model, entry and exit processes for individual plants (vessels) are endogenous, as well as output, employment and wages. This model is applied to a fishery of the Mediterranean Sea. The results provide both individual and aggregate data that can help managers in understanding the economic consequences of rebuilding strategies. In particular, this study shows that, for the application presented, all aggregate results improve if the stock rebuilding strategy is followed, while individual results depend on the indicator selected.
The population of beluga whales in Cook Inlet, Alaska, USA, declined by nearly half in the mid-1990s, primarily from an unsustainable harvest, and was listed as endangered in 2008. In 2014, abundance was ~340 whales, and the population trend during 1999-2014 was -1.3% yr-1. Cook Inlet beluga whales are particularly vulnerable to anthropogenic impacts, and noise that has the potential to reduce communication and echolocation range considerably has been documented in critical habitat; thus, noise was ranked as a high potential threat in the Cook Inlet beluga Recovery Plan. The current recovery strategy includes research on effects of threats potentially limiting recovery, and thus we examined the potential impact of anthropogenic noise in critical habitat, specifically, spatial displacement. Using a subset of data on anthropogenic noise and beluga detections from a 5 yr acoustic study, we evaluated the influence of noise events on beluga occupancy probability. We used occupancy models, which account for factors that affect detection probability when estimating occupancy, the first application of these models to examine the potential impacts of anthropogenic noise on marine mammal behavior. Results were inconclusive, primarily because beluga detections were relatively infrequent. Even though noise metrics (sound pressure level and noise duration) appeared in high-ranking models as covariates for occupancy probability, the data were insufficient to indicate better predictive ability beyond those models that only included environmental covariates. Future studies that implement protocols designed specifically for beluga occupancy will be most effective for accurately estimating the effect of noise on beluga displacement.
Despite their high value, the future of coral reefs is currently in jeopardy. Recent studies have shown that many reefs worldwide have lost 50–90% of live coral over the past 30–40 years (Baker 2014). Corals are dying worldwide as a result of multiple stressors, many of them human-induced (Pandolfi 2003). Conservation and restoration of coral reef habitats are key to their future and the future of nations that depend on them, including the United States. An important part of any conservation effort must be to reduce or eliminate the stressors that are causing reefs to become degraded. This article will outline some of the major threats to coral reefs and the strategies that everyone, whether living one mile or one thousand miles from a coral reef, can use to help reduce negative impacts on these ecosystems and preserve their services for years to come.
Relationships between angling effort and fish abundance have critical implications for the resilience and management of recreational fisheries, but these relationships have rarely been assessed empirically. Here, angling effort was related to fish abundance in three marine recreational fisheries in Florida, USA, through a suite of regression and time series methods that accounted for socio-economic and demographic variables. Overall, recreational angling effort was correlated with fish abundance, but further analyses provided little evidence of strong, causal relationships. Lack of strong relationships implies angling effort might increase in the future unrelated to fish abundance, a decoupling that could threaten the viability of fish populations in the absence of unpopular recreational effort limitation. The inability to establish more conclusive relationships between effort and fish abundance should motivate a future focus towards natural or manipulative experiments that may provide more powerful inferences.
Estimates of post-release mortality (PRM) rates for discarded bycatch are largely unknown across marine fisheries and represent a substantial source of uncertainty when estimating total fishery mortality. One way to predict PRM is through the use of reflex action mortality predictors (RAMP), whereby the presence or absence of target reflexes and known post-release fate are used to create a delayed mortality model. We employed reflex impairment assessments in concert with post-capture caging and video monitoring to predict 5-d PRM rates for the deep-sea giant isopod Bathynomus giganteus, a common bycatch species in numerous deepwater fisheries worldwide, and also considered the factors contributing to mortality. Mortality rates 5 d post-capture ranged from 50 to 100% and both RAMP scores and time at the surface were significant predictors of mortality, although our conclusions regarding the effect of surface time are limited. In-cage video documented little movement within the 24-h monitoring period following capture, and it appeared that surviving individuals often fed within the holding period after cage deployment. Our results suggest that PRM in B. giganteus is common and that this unaccounted source of mortality should be quantified for other deep-sea crustaceans captured as bycatch.
This study aims to evaluate FAD use patterns, co-management arrangements and livelihoods of pelagic fisheries with particular emphasis on changes that have occurred in recent years, during the CARIFICO project. It also aims to assess the factors influencing the decision of fisheries to set and maintain public and private FADs.
Coral reef restoration focuses on scleractinian corals, excluding other groups that provide structural complexity to these threatened ecosystems. Giant clams share the role of ecosystem engineers alongside corals in the Indo-Pacific, but overfishing has caused widespread local extinctions. Aquaculture reduces pressure on wild populations and captive bred juveniles have been used to restore extinct populations. However, giant clam restoration has not been attempted before with adults until now. A total of 150 captive bred, adult giant clams (Tridacna maxima), 4–10 years old, shell length 99–198 mm, were relocated to a healthy reef (control site) and a restored reef (treatment site) at a coral reef restoration project in Seychelles, Indian Ocean, in two sequential experiments. The first experiment started in April (calm season, NW Monsoon), deployed 30 clams, 15 per site at 12 m depth, and lasted 20 weeks. The second experiment started in June (rough season, SE Monsoon), deployed 120 clams, 60 per site at 6 and 12 m depth, and lasted 11 weeks. T. maxima were measured and double tagged with glue-on shellfish tags prior to deployment. Survival was monitored weekly or biweekly depending on weather conditions. Remote GoPro video cameras confirmed the transplanted T. maxima displayed normal behavior. Survival rates from Kaplan-Meier curves were 3.3–66.7%. Median survival time was 2 weeks to more than 20 weeks. T. maxima survived 3.3–5 times longer at the treatment site than at the control site in both experiments. T. maxima mortality was a combination of transplant season, predators, byssal re-attachment and wave swells. In the first experiment, mortality was due to octopus predation and 1.8 times higher at the control site than at the treatment site. The control site was an older reef with more octopus dens resulting in higher predation. T. maxima transplanted in April had 1 month to re-attach before the rough season started, but those transplanted in June were mostly dislodged by wave swells. These results show captive bred, adult T. maxima survive restoration in the wild. The potential synergy of jointly restoring corals and giant clams in the Indo-Pacific region is discussed.
This paper provides coastal scenic values of 100 sites along coastal Cuba by the use of a weighted, fuzzy logic, based checklist containing 26 physical/human factors. Sites were categorized into five classes from Class I, top grade scenery, to Class V, poor scenery. Seven beaches belonged to Class I, e.g. rural areas with a low impact of human activities and high scores of natural parameters. Most Class II beaches were located at international resort areas in cays having white coral sand beaches, turquoise water and vigorous vegetation together with a low impact of tourist developments because of appropriate location and design. Classes III, IV and V presented a wide distribution and their lower scores were linked to a poor environmental setting. Results allow for improvements to beach management plans to be formulated for current international tourist destinations (in cays) and other potentially attractive coastal areas at new developing tourist destinations.