Literature Library

Currently indexing 10148 titles

The Active Reef Restoration Toolbox is a Vehicle for Coral Resilience and Adaptation in a Changing World

Rinkevich . The Active Reef Restoration Toolbox is a Vehicle for Coral Resilience and Adaptation in a Changing World. Journal of Marine Science and Engineering [Internet]. 2019 ;7(7):201. Available from: https://www.mdpi.com/2077-1312/7/7/201
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The accelerating marks of climate change on coral-reef ecosystems, combined with the recognition that traditional management measures are not efficient enough to cope with climate change tempo and human footprints, have raised a need for new approaches to reef restoration. The most widely used approach is the “coral gardening” tenet; an active reef restoration tactic based on principles, concepts, and theories used in silviculture. During the relatively short period since its inception, the gardening approach has been tested globally in a wide range of reef sites, and on about 100 coral species, utilizing hundreds of thousands of nursery-raised coral colonies. While still lacking credibility for simulating restoration scenarios under forecasted climate change impacts, and with a limited adaptation toolkit used in the gardening approach, it is still deficient. Therefore, novel restoration avenues have recently been suggested and devised, and some have already been tested, primarily in the laboratory. Here, I describe seven classes of such novel avenues and tools, which include the improved gardening methodologies, ecological engineering approaches, assisted migration/colonization, assisted genetics/evolution, assisted microbiome, coral epigenetics, and coral chimerism. These are further classified into three operation levels, each dependent on the success of the former level. Altogether, the seven approaches and the three operation levels represent a unified active reef restoration toolbox, under the umbrella of the gardening tenet, focusing on the enhancement of coral resilience and adaptation in a changing world. 

First attempts towards the restoration of gorgonian populations on the Mediterranean continental shelf

Montseny M, Linares C, Viladrich N, Olariaga A, Carreras M, Palomeras N, Gracias N, Istenič K, Garcia R, Ambroso S, et al. First attempts towards the restoration of gorgonian populations on the Mediterranean continental shelf. Aquatic Conservation: Marine and Freshwater Ecosystems [Internet]. 2019 ;29(8):1278 - 1284. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1002/aqc.3118
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $42.00
Type: Journal Article
  1. In the Mediterranean Sea, gorgonians are among the main habitat‐forming species of benthic communities on the continental shelf and slope, playing an important ecological role in coral gardens.
  2. In areas where bottom trawling is restricted, gorgonians represent one of the main components of trammel net bycatch. Since gorgonians are long‐lived and slow‐growing species, impacts derived from fishing activities can have far‐reaching and long‐lasting effects, jeopardizing their long‐term viability. Thus, mitigation and ecological restoration initiatives focusing on gorgonian populations on the continental shelf are necessary to enhance and speed up their natural recovery.
  3. Bycatch gorgonians from artisanal fishermen were transplanted into artificial structures, which were then deployed at 85 m depth on the outer continental shelf of the marine protected area of Cap de Creus (north‐west Mediterranean Sea, Spain). After 1 year, high survival rates of transplanted colonies (87.5%) were recorded with a hybrid remotely operated vehicle.
  4. This pilot study shows, for the first time, the survival potential of bycatch gorgonians once returned to their habitat on the continental shelf, and suggests the potential success of future scaled‐up restoration activities.

Considerations for maximizing the adaptive potential of restored coral populations in the western Atlantic

Baums IB, Baker AC, Davies SW, Grottoli AG, Kenkel CD, Kitchen SA, Kuffner IB, LaJeunesse TC, Matz MV, Miller MW, et al. Considerations for maximizing the adaptive potential of restored coral populations in the western Atlantic. Ecological Applications [Internet]. 2019 . Available from: https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/eap.1978?casa_token=jpiZfIIXy-4AAAAA:pXxNJhLdK6n_ZxOekdqYCN5HISrp9q_y0nWPAdeMQb997kogW0XyoIdPYEw4xHgN2T0VCGnSp64ic60
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $42.00
Type: Journal Article

Active coral restoration typically involves two interventions: crossing gametes to facilitate sexual larval propagation; and fragmenting, growing, and outplanting adult colonies to enhance asexual propagation. From an evolutionary perspective, the goal of these efforts is to establish self‐sustaining, sexually reproducing coral populations that have sufficient genetic and phenotypic variation to adapt to changing environments. Here, we provide concrete guidelines to help restoration practitioners meet this goal for most Caribbean species of interest. To enable the persistence of coral populations exposed to severe selection pressure from many stressors, a mixed provenance strategy is suggested: genetically unique colonies (genets) should be sourced both locally as well as from more distant, environmentally distinct sites. Sourcing 3‐4 genets per reef along environmental gradients should be sufficient to capture a majority of intraspecies genetic diversity. It is best for practitioners to propagate genets with one or more phenotypic traits that are predicted to be valuable in the future, such as low partial mortality, high would healing rate, high skeletal growth rate, bleaching resilience, infectious disease resilience, and high sexual reproductive output. Some effort should also be reserved for underperforming genets because colonies that grow poorly in nurseries sometimes thrive once returned to the reef and may harbor genetic variants with as yet unrecognized value. Outplants should be clustered in groups of 4‐6 genets to enable successful fertilization upon maturation. Current evidence indicates that translocating genets among distant reefs is unlikely to be problematic from a population genetic perspective but will likely provide substantial adaptive benefits. Similarly, inbreeding depression is not a concern given that current practices only raise first‐generation offspring. Thus, proceeding with the proposed management strategies even in the absence of a detailed population genetic analysis of the focal species at sites targeted for restoration is the best course of action. These basic guidelines should help maximize the adaptive potential of reef‐building corals facing a rapidly changing environment.

Global biogeography of coral recruitment: tropical decline and subtropical increase

Price NN, Muko S, Legendre L, Steneck R, van Oppen MJH, Albright R, P Jr A, Carpenter RC, Chui APY, Fan TY, et al. Global biogeography of coral recruitment: tropical decline and subtropical increase. Marine Ecology Progress Series [Internet]. 2019 ;621:1 - 17. Available from: https://www.int-res.com/abstracts/meps/v621/p1-17/
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Despite widespread climate-driven reductions of coral cover on tropical reefs, little attention has been paid to the possibility that changes in the geographic distribution of coral recruitment could facilitate beneficial responses to the changing climate through latitudinal range shifts. To address this possibility, we compiled a global database of normalized densities of coral recruits on settlement tiles (corals m-2) deployed from 1974 to 2012, and used the data therein to test for latitudinal range shifts in the distribution of coral recruits. In total, 92 studies provided 1253 records of coral recruitment, with 77% originating from settlement tiles immersed for 3-24 mo, herein defined as long-immersion tiles (LITs); the limited temporal and geographic coverage of data from short-immersion tiles (SITs; deployed for <3 mo) made them less suitable for the present purpose. The results from LITs show declines in coral recruitment, on a global scale (i.e. 82% from 1974 to 2012) and throughout the tropics (85% reduction at <20° latitude), and increases in the sub-tropics (78% increase at >20° latitude). These trends indicate that a global decline in coral recruitment has occurred since 1974, and the persistent reduction in the densities of recruits in equatorial latitudes, coupled with increased densities in sub-tropical latitudes, suggests that coral recruitment may be shifting poleward.

Macroalgal biomass, growth rates, and diversity are influenced by submarine groundwater discharge and local hydrodynamics in tropical reefs

La Valle FF, Thomas FI, Nelson CE. Macroalgal biomass, growth rates, and diversity are influenced by submarine groundwater discharge and local hydrodynamics in tropical reefs. Marine Ecology Progress Series [Internet]. 2019 ;621:51 - 67. Available from: https://www.int-res.com/abstracts/meps/v621/p51-67/
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

It is critical to evaluate the in situ effects of multiple stressors on coastal community dynamics, especially those communities harboring high diversity such as coral reefs, in order to understand the resilience of these ecosystems, prepare coastal management for future scenarios, and aid in prioritizing restoration efforts. In this in situstudy, at 2 sites with gradients of submarine groundwater discharge (SGD), a suite of physical parameters (wave exposure index, wind exposure index, and depth) and an all-encompassing SGD chemical parameter (average nitrate + nitrite daily load) were measured along spatially cohesive and temporally relevant scales and used to model macroalgal growth, biomass, and diversity in Maunalua Bay, Hawai‘i. We showed that (1) species-specific macroalgal biomass is significantly related to SGD and one of the 2 exposure indices (i.e. wind exposure or wave exposure), (2) SGD and wave exposure play key roles in species-specific growth rates, and (3) SGD supports low diversity and increased biomass of species that can tolerate the biogeochemistry associated with SGD. Our work suggests that SGD and local hydrodynamics predict local variation in macroalgal growth, biomass, and diversity in tropical reefs.

Tourists’ aesthetic assessment of environmental changes, linking conservation planning to sustainable tourism development

Le D, Scott N, Becken S, Connolly RM. Tourists’ aesthetic assessment of environmental changes, linking conservation planning to sustainable tourism development. Journal of Sustainable Tourism [Internet]. 2019 :1 - 18. Available from: https://www.tandfonline.com/doi/abs/10.1080/09669582.2019.1632869
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $43.00
Type: Journal Article

Tourists often travel to experience the natural beauty of a destination such as the Great Barrier Reef (GBR) in Australia. This nature-based destination attracts millions of tourists every year because of its outstanding underwater aesthetics. Recently, parts of the GBR have been degraded by warming sea temperatures and other local anthropogenic influences, threatening the Reef aesthetics and tourism in the region. In order to deal with this topical issue, the current research investigates tourists’ aesthetic assessment of environmental changes in the GBR ecosystem. Research outcomes indicate that tourists’ perceived beauty of the Reef is sensitive to environmental changes. The disappearance of sea animals (colourful fish, turtle), degrading coral and decreasing water quality negatively influence their aesthetic assessment, which can reduce tourist visitation in the long-term. Hence, sustainable tourism development in the GBR regions can only be achieved when government support for environmental management is strengthened. Conservation programs of the GBR should expand beyond coral restoration for controlling water quality, reducing pollution and protecting aesthetically appealing sea animals.

Comparing the Underwater Soundscapes of Four U.S. National Parks and Marine Sanctuaries

Haver SM, Fournet MEH, Dziak RP, Gabriele C, Gedamke J, Hatch LT, Haxel J, Heppell SA, McKenna MF, Mellinger DK, et al. Comparing the Underwater Soundscapes of Four U.S. National Parks and Marine Sanctuaries. Frontiers in Marine Science [Internet]. 2019 ;6. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2019.00500/full?utm_source=F-NTF&utm_medium=EMLX&utm_campaign=PRD_FEOPS_20170000_ARTICLE
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Passive acoustic sensors provide a cost-effective tool for monitoring marine environments. Documenting acoustic conditions among habitats can provide insights into temporal changes in ecosystem composition and anthropogenic impacts. Agencies tasked with safeguarding marine protected areas, such as the U.S. National Park Service and U.S. National Oceanic and Atmospheric Administration’s Office of National Marine Sanctuaries, are increasingly interested in using long-term monitoring of underwater sounds as a means of tracking species diversity and ecosystem health. In this study, low-frequency passive acoustic recordings were collected fall 2014 – spring 2018, using standardized instrumentation, from four marine protected areas across geographically disparate regions of the U.S. Economic Exclusive Zone: Northwest Atlantic, Northeast Pacific, South Pacific, and Caribbean. Recordings were analyzed for differences in seasonal conditions and to identify acoustic metrics useful for resource assessment across all sites. In addition to comparing ambient sound levels, a species common to all four sites, the humpback whale (Megaptera novaeangliae), was used to compare biological sound detection. Ambient sound levels varied across the sites and were driven by differences in animal vocalization rates, anthropogenic activity, and weather. The highest sound levels [dBRMS (50 Hz–1.5 kHz)re 1 μPa] were recorded in the Northwest Atlantic in Stellwagen Bank National Marine Sanctuary (Stellwagen) during the boreal winter–spring resulting from bioacoustic activity, vessel traffic, and high wind speeds. The lowest sound levels [dBRMS (50 Hz–1.5 kHz) re 1 μPa] were recorded in the Northeast Pacific adjacent to a vessel-restricted area of Glacier Bay National Park and Preserve (Glacier Bay) during the boreal summer. Humpback whales were detected seasonally in the southern latitude sites, and throughout the deployment periods in the northern latitude sites. Temporal trends in band and spectrum sound levels in Glacier Bay and the National Park of American Samoa were primarily driven by biological sound sources, while trends in Stellwagen and the Buck Island Reef National Monument were primarily driven by anthropogenic sources. These results highlight the variability of ambient sound conditions in marine protected areas in U.S. waters, and the utility of long-term soundscape monitoring for condition assessment in support of resource management.

Matches and Mismatches Between Global Conservation Efforts and Global Conservation Priorities

Willer DF, Smith K, Aldridge DC. Matches and Mismatches Between Global Conservation Efforts and Global Conservation Priorities. Frontiers in Ecology and Evolution [Internet]. 2019 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fevo.2019.00297/full?utm_source=F-NTF&utm_medium=EMLX&utm_campaign=PRD_FEOPS_20170000_ARTICLE
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Species extinctions are occurring at an unprecedented rate and there is a global need to understand whether conservation effort is appropriately allocated to protect those species at risk. In this study three major measures of global conservation effort across IUCN Red List Threats and Habitats were assessed; staff time spent by the largest cluster of conservation organizations in the world—Cambridge Conservation Initiative, efforts by international NGOs through social media, and global conservation research publications since the year 2000. We find global conservation effort is generally aligned with global conservation priorities, but there are important outliers. Shrublands and rocky areas receive disproportionately little investment across all effort measures relative to the number of high extinction risk species, threats from residential and commercial development receive relatively low research and time investment despite social media attention, while marine areas and climate change receive more attention than expected. Governments and society must make critical conservation decisions in the context of rapid global change, and there is potential for key Threats or Habitats to receive less attention than required. The global conservation community would be wise to carefully consider and improve its understanding of effort-priority mismatches if the greatest number of high extinction risk species are to be protected.

A governance analysis of the Galápagos Marine Reserve

Jones PJS. A governance analysis of the Galápagos Marine Reserve. Marine Policy [Internet]. 2013 ;41:65 - 71. Available from: https://www.sciencedirect.com/science/article/pii/S0308597X12002606
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

The Galápagos Marine Reserve (GMR) has faced major governance challenges since its designation in 1998, largely due to the driving forces of immigration from the mainland; a heterogeneous population that has a mainland rather than an island identity; increasing demand for marine resources from global seafood markets; and the rapid growth of tourism. Until recently, the pressures related to these driving forces had challenged measures to promote the effectiveness of the GMR. Decisions taken through the participatory management structure were often undermined by a combination of civil unrest, illegal activities and lack of enforcement. A recent period of relative political stability, coupled with several new measures to address these driving forces, has improved the potential effectiveness of the governance framework. These measures include controls on immigration, the use of remote surveillance technologies to enforce fishing restrictions and a system for the improved management of tourism vessels. Whilst participative and economic incentives will continue to be important, increasing political will to promote long-term sustainability and related improvements in the use of legal incentives, including enforcement technologies and effective prosecutions for those who breach restrictions, are likely to be key elements of the governance framework. It is argued that these measures, coupled with the emergence of a more marine-aware generation of Galápagos citizens, should pave the way for major improvements in the effectiveness of the GMR, hopefully sufficiently strengthening the governance framework to withstand the major driving forces that could otherwise perturb it.

Global spatial risk assessment of sharks under the footprint of fisheries

Queiroz N, Humphries NE, Couto A, Vedor M, da Costa I, Sequeira AMM, Mucientes G, Santos AM, Abascal FJ, Abercrombie DL, et al. Global spatial risk assessment of sharks under the footprint of fisheries. Nature [Internet]. 2019 . Available from: https://www.nature.com/articles/s41586-019-1444-4
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $32.00
Type: Journal Article

Effective ocean management and the conservation of highly migratory species depend on resolving the overlap between animal movements and distributions, and fishing effort. However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.

Fishers’ knowledge improves the accuracy of food web model predictions

Bentley JW, Serpetti N, Fox C, Heymans JJ, Reid DG. Fishers’ knowledge improves the accuracy of food web model predictions Coll M. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article-abstract/76/4/897/5304545?redirectedFrom=fulltext
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $45.00
Type: Journal Article

Fisher's knowledge offers a valuable source of information to run parallel to observed data and fill gaps in our scientific knowledge. In this study we demonstrate how fishers' knowledge of historical fishing effort was incorporated into an Ecopath with Ecosim (EwE) model of the Irish Sea to fill the significant gap in scientific knowledge prior to 2003. The Irish Sea model was fitted and results compared using fishing effort time-series based on: (i) scientific knowledge, (ii) fishers' knowledge, (iii) adjusted fishers' knowledge, and (iv) a combination of (i) and (iii), termed “hybrid knowledge.” The hybrid model produced the best overall statistical fit, capturing the biomass trends of commercially important stocks. Importantly, the hybrid model also replicated the increase in landings of groups such as “crabs & lobsters” and “epifauna” which were poorly simulated in scenario (i). Incorporating environmental drivers and adjusting vulnerabilities in the foraging arena further improved model fit, therefore the model shows that both fishing and the environment have historically influenced trends in finfish and shellfish stocks in the Irish Sea. The co-production of knowledge approach used here improved the accuracy of model simulations and may prove fundamental for developing ecosystem-based management advice in a global context.

Organic ultraviolet filters in nearshore waters and in the invasive lionfish (Pterois volitans) in Grenada, West Indies

Horricks RA, Tabin SK, Edwards JJ, Lumsden JS, Marancik DP. Organic ultraviolet filters in nearshore waters and in the invasive lionfish (Pterois volitans) in Grenada, West Indies Aherne J. PLOS ONE [Internet]. 2019 ;14(7):e0220280. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220280
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Sunscreens and other personal care products use organic ultraviolet (UV) filters such as oxybenzone, 4-methylbenzylidene camphor, Padimate-O, and octyl methoxycinnamate to prevent damage to human skin. While these compounds are effective at preventing sunburn, they have a demonstrated negative effect on cells and tissues across taxonomic levels. These compounds have a relatively short half-life in seawater but are continuously re-introduced via recreational activities and wastewater discharge, making them environmentally persistent. Because of this, testing seawater samples for the presence of these compounds may not be reflective of their abundance in the environment. Bioaccumulation of organic ultraviolet filters in a high-trophic level predator may provide greater insight to the presence and persistence of these compounds. To address this, the present study collected seawater samples as well as muscle and stomach content samples from the invasive Pacific lionfish (Pterois volitans) in the nearshore waters of Grenada, West Indies to examine the use of lionfish as potential bioindicator species. Seawater and lionfish samples were collected at four sites that are near point sources of wastewater discharge and that receive a high number of visitors each year. Samples were tested for the presence and concentrations of oxybenzone, 4-methylbenzylidene camphor (4-MBC), Padimate-O, and octyl methoxycinnamate (OMC) using liquid chromatography-mass spectrometry. Oxybenzone residues were detected in 60% of seawater samples and OMC residues were detected in 20% of seawater samples. Seawater samples collected in the surface waters near Grenada’s main beach had oxybenzone concentrations more than ten times higher than seawater samples collected in less frequently visited areas and the highest prevalence of UV filters in lionfish. Residues of oxybenzone were detected in 35% of lionfish muscle and 4-MBC residues were detected in 12% of lionfish muscle. Padimate-O was not detected in either seawater or lionfish samples. No organic UV filters were detected in lionfish stomach contents. Histopathologic examination of lionfish demonstrated no significant findings attributed to UV filter toxicity. These findings report UV filter residue levels for the first time in inshore waters in Grenada. Results indicate that lionfish may be bioaccumulating residues and may be a useful sentinel model for monitoring organic ultraviolet filters in the Caribbean Sea.

Escaped farmed Atlantic salmon in Norwegian rivers during 1989–2013

Diserud OH, Fiske P, Sægrov H, Urdal K, Aronsen T, Lo H, Barlaup BT, Niemelä E, Orell P, Erkinaro J, et al. Escaped farmed Atlantic salmon in Norwegian rivers during 1989–2013. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article/76/4/1140/5289588
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

We report on the data from an extensive monitoring programme for the occurrence of escaped farmed Atlantic salmon (Salmo salar) in Norwegian rivers for 25 years. This monitoring started as a 3-year research programme in 1989 and was followed by management authorities to cover the proportional occurrence of escaped farmed Atlantic salmon in rivers during summer and autumn before spawning. Farmed salmon were distinguished from wild salmon by growth patterns in the scales. More than 362 000 salmon were registered by this programme. Here we present the historical data on escaped farmed salmon in catches 1989–2013 and a methodology for calculating averages across summer and autumn capture in rivers, across years and in regions, using weighted and unweighted observations. Catches of escaped farmed salmon show large spatial and temporal variation, with the early 1990s and early 2000s being periods of large influxes of farmed fish. Western Norway and parts of middle and northern Norway have shown particularly high incidences of escaped farmed fish. Because escaped farmed Atlantic salmon are competing and interbreeding with wild Atlantic salmon, as well as increasing the spread of disease-causing agents, they have become a major force driving the abundance and evolution of Atlantic salmon.

Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology

Figgener C, Bernardo J, Plotkin PT. Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology. Biological Reviews [Internet]. 2019 . Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12543
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The idea that interspecific variation in trophic morphology among closely related species effectively permits resource partitioning has driven research on ecological radiation since Darwin first described variation in beak morphology among Geospiza.

Marine turtles comprise an ecological radiation in which interspecific differences in trophic morphology have similarly been implicated as a pathway to ecopartition the marine realm, in both extant and extinct species. Because marine turtles are charismatic flagship species of conservation concern, their trophic ecology has been studied intensively using stable isotope analyses to gain insights into habitat use and diet, principally to inform conservation management. This legion of studies provides an unparalleled opportunity to examine ecological partitioning across numerous hierarchical levels that heretofore has not been applied to any other ecological radiation. Our contribution aims to provide a quantitative analysis of interspecific variation and a comprehensive review of intraspecific variation in trophic ecology across different hierarchical levels marshalling insights about realised trophic ecology derived from stable isotopes.

We reviewed 113 stable isotope studies, mostly involving single species, and conducted a meta‐analysis of data from adults to elucidate differences in trophic ecology among species. Our study reveals a more intricate hierarchy of ecopartitioning by marine turtles than previously recognised based on trophic morphology and dietary analyses. We found strong statistical support for interspecific partitioning, as well as a continuum of intraspecific trophic sub‐specialisation in most species across several hierarchical levels. This ubiquity of trophic specialisation across many hierarchical levels exposes a far more complex view of trophic ecology and resource‐axis exploitation than suggested by species diversity alone. Not only do species segregate along many widely understood axes such as body size, macrohabitat, and trophic morphology but the general pattern revealed by isotopic studies is one of microhabitat segregation and variation in foraging behaviour within species, within populations, and among individuals.

These findings are highly relevant to conservation management because they imply ecological non‐exchangeability, which introduces a new dimension beyond that of genetic stocks which drives current conservation planning.

Perhaps the most remarkable finding from our data synthesis is that four of six marine turtle species forage across several trophic levels. This pattern is unlike that seen in other large marine predators, which forage at a single trophic level according to stable isotopes. This finding affirms suggestions that marine turtles are robust sentinels of ocean health and likely stabilise marine food webs. This insight has broader significance for studies of marine food webs and trophic ecology of large marine predators.

Beyond insights concerning marine turtle ecology and conservation, our findings also have broader implications for the study of ecological radiations. Particularly, the unrecognised complexity of ecopartitioning beyond that predicted by trophic morphology suggests that this dominant approach in adaptive radiation research likely underestimates the degree of resource overlap and that interspecific disparities in trophic morphology may often over‐predict the degree of realised ecopartitioning. Hence, our findings suggest that stable isotopes can profitably be applied to study other ecological radiations and may reveal trophic variation beyond that reflected by trophic morphology.

Exploring diversity in expert knowledge: variation in local ecological knowledge of Alaskan recreational and subsistence fishers

Chan MN, Beaudreau AH, Loring PA. Exploring diversity in expert knowledge: variation in local ecological knowledge of Alaskan recreational and subsistence fishers. ICES Journal of Marine Science [Internet]. 2018 . Available from: https://academic.oup.com/icesjms/article/76/4/913/5259367
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Local ecological knowledge (LEK) of resource users is a valuable source of information about environmental trends and conditions. However, many factors influence how people perceive their environment and it may be important to identify sources of variation in LEK when using it to understand ecological change. This study examined variation in LEK arising from differences in people’s experience in the environment. From 2014 to 2016, we conducted 98 semi-structured interviews with subsistence fishers and recreational charter captains in four Alaskan coastal communities to document LEK of seven fish species. Fishers observed declines in fish abundance and body size, though the patterns varied among species, regions, and fishery sectors. Overall, subsistence harvesters provided a longer-term view of abundance changes compared with charter captains. Regression analyses indicated that the extent of people’s fishing areas and their years of fishing experience were relatively important factors in explaining variation in fishers’ perceptions of fish abundance. When taken together, perspectives from fishers in multiple regions and sectors can provide a more complete picture of changes in nearshore fish populations than any source alone. These findings underscore the importance of including people with different types of expertise in local knowledge studies designed to document environmental change.

Decreases in length at maturation of Mediterranean fishes associated with higher sea temperatures

Goldberg DShapiro, van Rijn I, Kiflawi M, Belmaker J. Decreases in length at maturation of Mediterranean fishes associated with higher sea temperatures. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article-abstract/76/4/946/5310316?redirectedFrom=fulltext
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $45.00
Type: Journal Article

Fish size at maturation influences lifetime reproductive success and is an important parameter in managing stocks. Fish tend to reach maturity at a smaller size in warmer water; however, the generality of this pattern is a matter of controversy. The mechanisms by which temperature influences fish size at maturation are not well understood, particularly in natural populations, but may have broad implications if climate change continues to warm the seas. In this study, we use populations of 16 fish species across the Mediterranean Sea to evaluate the association between different temperature metrics and fish size at maturation, and to understand the variation among species. We found that both mean annual temperature and growing degree days (GDD) were the best supported environmental predictors of fish size at maturation. This suggests that the mechanisms affecting size at maturation may differ from those affecting maximum size, for which maximum temperature was the best predictor. Across species, we found that the effect of temperature is stronger for more active species, while other species-level predictors had limited influence. The correlation of fish size at maturation to specific temperature metrics should help fisheries and conservation programmes better predict the effects of climate change on fish populations.

Enlightening the ocean’s twilight zone

Kaartvedt S, Langbehn TJ, Aksnes DL. Enlightening the ocean’s twilight zone. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article/76/4/803/5306603
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

By definition, the mesopelagic twilight zone extends from 200 to 1000 m depth. Rather than confining the twilight zone to a certain depth interval, we here propose a definition that covers absolute light intensities ranging from 10−9 to 10−1 μmol quanta m−2 s−1. The lowest intensity of this twilight habitat corresponds to the visual threshold of lanternfishes (Myctophidae). The highest intensity corresponds to the upper light exposure of pearlsides (Maurolicusspp.), which have a unique eye adapted to higher light intensities than the lanternfishes. By this definition, the daytime twilight habitat extends deeper than 1000 m in very clear oceanic water, while may even be largely located above 200 m in very murky coastal waters. During moonlit nights in clear water, the twilight habitat would still extend deep into the mesopelagic depth zone, while becoming compressed toward the surface in dark nights. Large variation in night light, from 10−3 μmol quanta m−2 s−1 during moonlit nights to 10−8 μmol quanta m−2 s−1 in dark overcast nights, implies that division of light into night- and daylight is insufficient to characterize the habitats and distributional patterns of twilight organisms. Future research will benefit from in situ light measurements, during night- as well as daytime, and habitat classification based on optical properties in addition to depth. We suggest some pertinent research questions for future exploration of the twilight zone.

A data-limited method for assessing cumulative fishing risk on bycatch

Zhou S, Daley RM, Fuller M, Bulman CM, Hobday AJ. A data-limited method for assessing cumulative fishing risk on bycatch. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article-abstract/76/4/837/5303697?redirectedFrom=fulltext
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $45.00
Type: Journal Article

To assess fishing effects on data-poor species, impact can be derived from spatial overlap between species distribution and fishing effort and gear catchability. Here, we enhance the existing sustainability assessment for fishing effect method by estimating gear efficiency and heterogeneous density from sporadic catch data. We apply the method to two chondrichthyan bycatch species, Bight Skate and Draughtboard Shark in Australia, to assess cumulative fishing mortality (Fcum) from multiple fisheries. Gear efficiency is estimated from a Bayesian mixture distribution model and fish density is predicted by a generalized additive model. These results, combined with actual fishing effort, allow estimation of fishing mortality in each sector and subsequently, the Fcum. Risk is quantified by comparing Fcum with reference points based on life history parameters. When only the point estimates were considered, our result indicates that for the period 2009 and 2010 Bight Skate caught in 14 fisheries was at high cumulative risk (Fcum ≥ Flim) while Draughtboard Shark caught by 19 fisheries was at low cumulative risk (Fcum ≤ Fmsy). Because of the high cost of conducting cumulative risk assessments, we recommend examining the distribution of fishing effort across fisheries before carrying out the assessments.

How we can all stop killing whales: a proposal to avoid whale entanglement in fishing gear

Moore MJ. How we can all stop killing whales: a proposal to avoid whale entanglement in fishing gear. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article/76/4/781/5288134
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

 

Whales are federally protected by the Marine Mammal Protection Act; endangered species, such as the North Atlantic right whale, receive additional protection under the Endangered Species Act. However, their regulations have failed to satisfy conservation and animal welfare concerns. From 1990 to 2011 the North Atlantic right whale (Eubalaena glacialis, NARW) population grew at a mean of 2.8% annually. However, population trends reversed since 2011; the species is in decline, with only ∼100 reproductively active females remaining. This failure is driven by vessel collisions and increasingly fatal and serious entanglement in fixed fishing gear, whose rope strength has increased substantially. Chronic entanglement, drag, and associated morbidity have been linked to poor fecundity. Genuine solutions involve designating areas to be avoided and speed restrictions for ships and removing fishing trap ropes from the water column. A trap fishing closure for NARW habitat in the Cape Cod Bay (U.S.) area has been in place seasonally since 2015. 2017 mortalities in Eastern Canada elicited substantive management changes whereby the 2018 presence of NARW in active trap fishing areas resulted in an effective closure. To avoid these costly closures, the traditional trap fishery model of rope end lines attached to surface marker buoys has to be modified so that traps are marked virtually, and retrieved with gear that does not remain in the water column except during trap retrieval. Consumer demand for genuinely whale-safe products will augment and encourage the necessary regulatory changes so that trap fisheries conserve target and nontarget species.

Stock collapse or stock recovery? Contrasting perceptions of a depleted cod stock

Cook RM. Stock collapse or stock recovery? Contrasting perceptions of a depleted cod stock. ICES Journal of Marine Science [Internet]. 2019 . Available from: https://academic.oup.com/icesjms/article/76/4/787/5299883
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

ICES assessments of cod (Gadus morhua) in the west of Scotland (ICES Division 6a) suggest the biomass has collapsed and that fishing mortality rate (F) has remained high. In contrast, other stocks in the same fishery, and adjacent cod stocks all show marked declines in fishing mortality and some recovery of the biomass. The perception of the status of 6a cod appears to be dependent on the assumption that the fishery exploitation pattern is flat topped. An assessment that allows the exploitation to take a domed shape produces results that suggest a marked decline in fishing mortality rate and that the spawning stock biomass has recovered to the minimum biomass reference point, Blim. The reduction in F is consistent with substantial reductions in fishing effort and shows a similar pattern to stocks taken within the same fishery. The management implications arising from the two assessments differ substantially. The analysis indicates that benchmark assessments need to test assessment model conditioning assumptions more widely and that management advice needs to consider a more comprehensive range of information about the stock and fishery.

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