MPA policy: What lies behind the science?

What the current policy debate on marine protected areas (MPAs) and marine reserves (MRs) has failed to address is the fact that protection of the marine environment has as much to do with scientists, and others values as it has to do with science. To date natural science has played a dominant role in the implementation of MPAs, yet normative considerations which are embedded in the way scientists and the wider community think about the condition the marine environment should be in, and which may influence decision-making, are rarely acknowledged or discussed. This paper seeks to correct that deficiency by investigating the values that lie behind the natural science of MPAs. With the aid of epistemic community, advocacy coalition and discourse coalition theories of policy networks, this article explores the role science and scientists have played in influencing policy on MPAs at the global and national level, and looks at the extent to which normative conceptualisations within and beyond natural science have influenced the debate

Trophodynamics and functional feeding groups of North Sea fauna: a combined stable isotope and fatty acid approach

The trophodynamics of pelagic and benthic animals of the North Sea, North Atlantic shelf, were assessed using stable isotope analysis (SIA) of natural abundance carbon and nitrogen isotopes, lipid fingerprinting and compound-specific SIA (CSIA) of phospholipid-derived fatty acids (PLFAs). Zooplankton (z), epi- and supra-benthic macrofauna were collected in the Southern Bight, at the Oyster Grounds and at North Dogger, 111 km north of the Dogger Bank. The study included 22 taxonomic groups with particular reference to Mollusca (Bivalvia and Gastropoda) and Crustacea. Primary consumers (Bivalvia) were overall most 15N enriched in the southern North Sea (6.1‰) and more depleted in the Oyster Grounds (5.5‰) and at North Dogger (2.8‰) demonstrating differences in isotopic baselines for bivalve fauna between the study sites. Higher trophic levels also followed this trend. Over an annual cycle, consumers tended to exhibit 15N depletion during spring followed by 15N enriched signatures in autumn and winter. The observed seasonal changes of ? 15N were more pronounced for suspension feeders and deposit feeders (dfs) than for filter feeders (ffs). The position of animals in plots of ? 13C and ? 15N largely concurred with the expected position according to literature-based functional feeding groups. PLFA fingerprints of groups such as z were distinct from benthic groups, e.g. benthic ffs and dfs, and predatory macrobenthos. ? 13CPLFA signatures indicated similarities in 13C moiety sources that constituted ? 13CPLFA. Although functional groups of pelagic zooplankton and (supra-) benthic animals represented phylogenetically distinct consumer groups, ? 13CPLFA demonstrated that both groups were supported by pelagic primary production and relied on the same macronutrients such as PLFAs. Errors related to the static categorization of small invertebrates into fixed trophic positions defined by phylogenetic groupings rather than by functional feeding groups, and information on seasonal trophodynamic variability, may have implications for the reliability of numerical marine ecosystem models

249–267 Predicting indirect effects of fishing in Mediterranean rocky littoral communities using a dynamic simulation model

Abstract Modelling may significantly enhance our understanding of the potential impacts of fisheries at larger spatial scales and on groups that would otherwise be very difficult to study. An aggregated biomass-based simulation model of a Mediterranean infralittoral zone was developed and used to carry out fishing 'experiments' where fishing intensity and catch selection were varied. The model was constructed for the Bay of Calvi, Corsica, using the Ecopath with Ecosim software, and was composed of 27 compartments, including seabirds, 11 groups of fish, 12 groups of invertebrates, 2 primary producers, bacteria and detritus. Several instances of indirect fishing effects ('trophic cascades' and 'keystone predation') have been proposed from anecdotal evidence in the western Mediterranean. Model outcomes provided little support for the widely accepted paradigm that fishing, by removing invertebrate-feeding fish, allows increases in the biomass of sea urchins and as a consequence the formation of overgrazed 'barrens' of bare substrate. Simulated harvesting of sea urchins by humans did, however, results in an increase of macroalgal biomass as reported previously. Intensified fishing pressure on 'macrocarnivorous' fish resulted in a 'release' of small fish species (e.g. blennies), and as a consequence a decline in the biomass of some small invertebrates on which they feed (e.g. amphipods). Increased fishing on large 'piscivores' resulted in increases in other small fish groups and consequential effects on other benthic invertebrate groups (e.g. polychaetes). Depletion of piscivorous fish resulted in a dramatic increase in the biomass of seabirds, which apparently compete with piscivores for small demersal and pelagic fish. An intensification of fishing pressure overall resulted in an increase in cephalopod biomass. Responses of target species to increased fishing pressure were most marked within the first 5 years of the new fishing regime. Indirect responses exhibited varying degrees of inertia, and biomasses of many groups did not assume a new equilibrium within the first 20 years of the simulation. The Mediterranean infralittoral rocky-bottom ecosystem was predicted to be relatively resilient to pulses of increased fishing and exhibited a high degree of detritus recycling. However, the speed and magnitude of ecosystem responses was shown to depend greatly on the extent of 'top-down' or 'bottom-up' control assumed for components within the system. Crow

Offshore pelagic subsidies dominate carbon inputs to coral reef predators

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Skinner, C., Mill, A. C., Fox, M. D., Newman, S. P., Zhu, Y., Kuhl, A., & Polunin, N. V. C. Offshore pelagic subsidies dominate carbon inputs to coral reef predators. Science Advances, 7(8), (2021): eabf3792, https://doi.org/10.1126/sciadv.abf3792.Coral reefs were traditionally perceived as productive hot spots in oligotrophic waters. While modern evidence indicates that many coral reef food webs are heavily subsidized by planktonic production, the pathways through which this occurs remain unresolved. We used the analytical power of carbon isotope analysis of essential amino acids to distinguish between alternative carbon pathways supporting four key reef predators across an oceanic atoll. This technique separates benthic versus planktonic inputs, further identifying two distinct planktonic pathways (nearshore reef-associated plankton and offshore pelagic plankton), and revealing that these reef predators are overwhelmingly sustained by offshore pelagic sources rather than by reef sources (including reef-associated plankton). Notably, pelagic reliance did not vary between species or reef habitats, emphasizing that allochthonous energetic subsidies may have system-wide importance. These results help explain how coral reefs maintain exceptional productivity in apparently nutrient-poor tropical settings, but also emphasize their susceptibility to future ocean productivity fluctuations.Sample analysis funding was provided by NERC LSMSF grant BRIS/102/0717 and BRIS/125/1418. C.S. was supported by a Newcastle University SAgE DTA studentship and a cooperative agreement with Banyan Tree

Patterns of coral-reef finfish species disappearances inferred from fishers' knowledge in global epicentre of marine shorefish diversity

In the Philippines, very high fishing pressure coincides with the globally greatest number of shorefish species, yet no long-term fisheries data are available to explore species-level changes that may have occurred widely in the most species rich and vulnerable marine ecosystem, namely coral reefs. Through 2655 face-to-face interviews conducted between August 2012 and July 2014, we used fishers' recall of past catch rates of reef-associated finfish to infer species disappearances from catches in five marine key biodiversity areas (Lanuza Bay, Danajon Bank, Verde Island Passage, Polillo Islands and Honda Bay). We modeled temporal trends in perceived catch per unit effort (CPUE) based on fishers' reports of typical good days' catches using Generalized Linear Mixed Modelling. Fifty-nine different finfish disappeared from catches between the 1950s and 2014; 42 fish were identified to species level, two to genus, seven to family and eight to local name only. Five species occurring at all sites with the greatest number of fishers reporting zero catches were the green bumphead parrotfish (Bolbometopon muricatum), humphead wrasse (Cheilinus undulatus), African pompano (Alectis ciliaris), giant grouper (Epinephelus lanceolatus) and mangrove red snapper (Lutjanus argentimaculatus). Between the 1950s and 2014, the mean perceived CPUE of bumphead parrotfish declined by 88%, that of humphead wrasse by 82%, African pompano by 66%, giant grouper by 74% and mangrove red snapper by 64%. These declines were mainly associated with excess and uncontrolled fishing, fish life-history traits like maximum body size and socio-economic factors like access to market infrastructure and services, and overpopulation. The fishers' knowledge is indicative of extirpations where evidence for these losses was otherwise lacking. Our models provide information as basis for area-based conservation and regional resource management particularly for the more vulnerable, once common, large, yet wide-ranging reef finfish species

STUDY ON MARKET PROCESS OF TUNA POLE-AND-LINE FISHERY IN EASTERN INDONESIA: A STUDY CASE IN SORONG, PAPUA BARAT PROVINCE

This research is a study of the way the small-scale pole-and-line tuna fishery in Sorong, Indonesia by examining official records of supply chains; key informant and fishers’ perceptions of marketing; and personal observations of landings and selling. The main finding of the study is that the pole-and-line fishers in Sorong have made strenuous efforts to escape the constrictions of middlemen by direct selling to processors.

Quantifying spatio-temporal consistency in the trophic ecology of two sympatric flatfishes

Sympatric flatfish predators may partition their resources in coastal environments to reduce competition and maximise foraging efficiency. However, the degree of spatial and temporal consistency in their trophic ecology is not well understood because dietary studies tend to overlook the heterogeneity of consumed prey. Increasing the spatial and temporal scale of dietary analyses can thus help to resolve predator resource use. We applied a stomach content and multi-tissue (liver and muscle) stable isotope (δ13C, δ15N and δ34S) approach to investigate the feeding habits of two co-occurring flatfish predators, common dab (Limanda limanda) and European plaice (Pleuronectes platessa), across four bays on the Northumberland coast (UK) over short (hours), medium (days) and long (months) temporal scales. Stomach content analyses showed spatial consistencies in predator resource use, whereas stable isotope mixing models revealed considerable inter-bay diet variability. Stomach contents also indicated high dietary overlap between L. limanda and P. platessa, while the stable isotope data yielded low to moderate levels of overlap, with cases of complete niche separation. Furthermore, individual specialisation metrics indicated consistently low levels of specialisation among conspecifics over time. We document changes in resource partitioning in space and time, reflecting diet switching in response to local and temporal fluctuations of patchily distributed prey. This study highlights how trophic tracers integrated at multiple temporal and spatial scales (within tens of kilometres) provide a more integrative approach for assessing the trophic ecology of sympatric predators in dynamic environments

Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems

Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Tracking seasonal changes in North Sea zooplankton trophic dynamics using stable isotopes

Trophodynamics of meso-zooplankton in the North Sea (NS) were assessed at a site in the southern NS, and at a shallow and a deep site in the central NS. Offshore and neritic species from different ecological niches, including Calanus spp., Temora spp. and Sagitta spp., were collected during seven cruises over 14 months from 2007 to 2008. Bulk stable isotope (SI) analysis, phospholipid-derived fatty acid (PLFA) compositions, and δ 13CPLFA data of meso-zooplankton and particulate organic matter (POM) were used to describe changes in zooplankton relative trophic positions (RTPs) and trophodynamics. The aim of the study was to test the hypothesis that the RTPs of zooplankton in the North Sea vary spatially and seasonally, in response to hydrographic variability, with the microbial food web playing an important role at times. Zooplankton RTPs tended to be higher during winter and lower during the phytoplankton bloom in spring. RTPs were highest for predators such as Sagitta sp. and Calanus helgolandicus and lowest for small copepods such as Pseudocalanus elongatus and zoea larvae (Brachyura). δ 15NPOM-based RTPs were only moderate surrogates for animals’ ecological niches, because of the plasticity in source materials from the herbivorous and the microbial loop food web. Common (16:0) and essential (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) structural lipids showed relatively constant abundances. This could be explained by incorporation of PLFAs with δ 13C signatures which followed seasonal changes in bulk δ 13CPOM and PLFA δ 13CPOM signatures. This study highlighted the complementarity of three biogeochemical approaches for trophodynamic studies and substantiated conceptual views of size-based food web analysis, in which small individuals of large species may be functionally equivalent to large individuals of small species. Seasonal and spatial variability was also important in altering the relative importance of the herbivorous and microbial food webs