2015-09-09

Modelling drift of pelagic offspring: the importance of egg surveys in providing a realistic model initialization

Espeland SHeiberg, Albretsen J, Olsen EMoland, Bodvin T. Modelling drift of pelagic offspring: the importance of egg surveys in providing a realistic model initialization. ICES Journal of Marine Science [Internet]. 2015 :fsv134. Available from: http://icesjms.oxfordjournals.org/lookup/doi/10.1093/icesjms/fsv134
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Having valid information about the location and dynamics of biological processes is important for coastal management. In this context modelling, the pelagic drift of early life stages has been shown to be an important tool for understanding the spatial scale of population dynamics in marine systems. Often simulated particles are released in hypothetical quantities at assumed spawning grounds with no or few field data to guide the model parametrization. In this study, we combine high-resolution field data and state-of-the-art oceanographic modelling and use a probabilistic approach to construct kernel density distributions of the dispersal of pelagic fish eggs. Specifically, the potential drift of pelagic offspring of cod (Gadus morhua) was investigated in a large, open fjord system in northern Norway by combining field observations of newly spawned cod eggs with simulations of particle movement using a semi-Lagrangian trajectory model with inputs from high-resolution hydrodynamic simulations. The larger part of the distribution of eggs after drift was located in the fjord, suggesting fjord scale recruitment dynamics. Finally, we also examined the drift of eggs released in a uniform distribution and found that lack of egg survey data gave an unrealistically large spread of egg particles within this fjord system.

Projecting the future state of marine ecosystems, “la grande illusion”?

Planque B. Projecting the future state of marine ecosystems, “la grande illusion”?. ICES Journal of Marine Science [Internet]. 2015 :fsv155. Available from: http://icesjms.oxfordjournals.org/lookup/doi/10.1093/icesjms/fsv155
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Using numerical models to project the state of marine ecosystems several decades into the future is commonly advocated, in particular for investigating the possible effects of climate change. Numerical models are useful to explore how ocean climate and other drivers may regulate the dynamics of marine ecosystems and constitute indispensable tools to test our conceptual representations of how marine systems function. However, I argue here that these models might be of limited use to project the future state of marine ecosystems decades into the future because several factors limit predictability. These include stochasticity, deterministic chaos, enablement vs. entailment, non-ergodicity, ecological surprises, irreducibility, and limits to upscaling. Many simulations of ecosystem states in the distant future may be no more than a “grande illusion” until explicit evaluations of how uncertainties increase with the time horizon of projection are performed.

Natural vs. fishing disturbance: drivers of community composition on traditional king scallop, Pecten maximus, fishing grounds

Szostek CL, Murray LG, Bell E, Rayner G, Kaiser MJ. Natural vs. fishing disturbance: drivers of community composition on traditional king scallop, Pecten maximus, fishing grounds. ICES Journal of Marine Science [Internet]. 2015 :fsv152. Available from: http://icesjms.oxfordjournals.org/lookup/doi/10.1093/icesjms/fsv152
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Scallop dredging is considered to be one of the most damaging forms of fishing to benthic habitats, although these effects vary among different habitats. The present study characterizes the biological communities that occur within the spatial limits of the English Channel king scallop dredge fishery in relation to key environmental drivers [mean seabed temperature; seabed temperature range; interannual temperature variation; bed shear stress (BSS); substrate characteristics; and depth] and across a gradient of scallop dredging intensity derived from vessel monitoring system data. Dredge fishing intensity was not correlated with species richness, species diversity, or species composition. However, increasing tidal BSS had a significant negative correlation with species richness and diversity. This outcome indicates that it is not possible to demonstrate that there is an effect of scallop fishing within the current spatial limits of the king scallop dredge fishery. This may be because historical dredge fishing could have already altered the benthic communities within the area of the scallop fishery to those that are resilient to scallop dredging, or that fishing disturbance has no impact over and above natural physical disturbance within the fishery. An analysis of biological and life history traits revealed that there was no relationship between recent fishing intensity, or BSS, and the functional composition of the communities present. However, even the lowest BSS values in the present study could be considered relatively high compared with areas outside the spatial boundaries of the fishery. Two distinct habitat groups were identified, based on the environmental drivers. These two groups were largely characterized by depth: deep (western) and shallow (eastern) sites. Species with traits that increase resilience to physical disturbance were abundant across all sample sites. Management concerning the environmental impacts of the fishery is discussed in terms of the spatial footprint of the fishery and predicted recovery time-scales for the associated benthic communities.

Climate change alters the structure of arctic marine food webs due to poleward shifts of boreal generalists

Kortsch S, Primicerio R, Fossheim M, Dolgov AV, Aschan M. Climate change alters the structure of arctic marine food webs due to poleward shifts of boreal generalists. Proceedings of the Royal Society B: Biological Sciences [Internet]. 2015 ;282(1814). Available from: http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2015.1546
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Climate-driven poleward shifts, leading to changes in species composition and relative abundances, have been recently documented in the Arctic. Among the fastest moving species are boreal generalist fish which are expected to affect arctic marine food web structure and ecosystem functioning substantially. Here, we address structural changes at the food web level induced by poleward shifts via topological network analysis of highly resolved boreal and arctic food webs of the Barents Sea. We detected considerable differences in structural properties and link configuration between the boreal and the arctic food webs, the latter being more modular and less connected. We found that a main characteristic of the boreal fish moving poleward into the arctic region of the Barents Sea is high generalism, a property that increases connectance and reduces modularity in the arctic marine food web. Our results reveal that habitats form natural boundaries for food web modules, and that generalists play an important functional role in coupling pelagic and benthic modules. We posit that these habitat couplers have the potential to promote the transfer of energy and matter between habitats, but also the spread of pertubations, thereby changing arctic marine food web structure considerably with implications for ecosystem dynamics and functioning.

Fuzzy analytic network process approach to evaluate land and sea criteria for land use planning in coastal areas

Najafinasab F, Karbassi AReza, Ghoddousi J. Fuzzy analytic network process approach to evaluate land and sea criteria for land use planning in coastal areas. Ocean & Coastal Management [Internet]. 2015 ;116:368 - 381. Available from: http://www.sciencedirect.com/science/article/pii/S0964569115002136
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Coastal areas are marginal regions between the land and sea. These areas have environmental value, but over-development imposes pressures on their ecosystems and brings about a multitude of challenges. Negative environmental impacts such as land-based source pollution are not only limited to land but also have adverse effects on the marine environment. Sustainable land-use planning has been applied to balance economic production, social needs, and environmental conservation in coastal areas. While previous studies have focused on land oriented criteria, they did not consider the interactions with adjacent marine environments. The purpose of this paper is to select criteria and outline the importance of integrating sea and land criteria in the context of land-use planning in coastal areas of Iran. This is the first time that the Decision Making Trial and Laboratory Model (DEMATEL) and Analytical Network Process (ANP) method with fuzzy logic have been used to select land-and sea-oriented criteria for land-use planning. The results illustrate that “biodiversity of fauna and flora at sea,” “area of spawning,” “biodiversity of fauna and flora in land,” “breeding grounds,” and “distribution of fauna and flora at sea” are the five most important criteria for coastal land-use planning. The integrated framework presented in this paper provides a holistic approach for coastal land-use planning.

Building a cross-strait cooperation mechanism for the conservation and management of fishery resources in the South China Sea

Jiang Y, Xue X. Building a cross-strait cooperation mechanism for the conservation and management of fishery resources in the South China Sea. Ocean & Coastal Management [Internet]. 2015 ;116:318 - 330. Available from: http://www.sciencedirect.com/science/article/pii/S0964569115300090
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Fishery resources in the South China Sea play an essential role in the economic and social development of Mainland China and Taiwan as well as the conjunct regional communities. Beyond the sovereignty disputes and competing maritime claims, the over-exploitation and unregulated harvesting of fishery resources are placing serious pressures on the health and security of the South China Sea ecosystem. This article argues that sub-regional cooperative actions with a regional thinking were deemed effective approaches for the sustainable development of regional fisheries before the establishment of regional arrangements. The lack of collective approach for fisheries conservation and management in shared waters means that a mutually beneficial situation for Mainland China and Taiwan is yet to be achieved. An integrated and collaborative mechanism for cross-strait fisheries cooperation and ecological management is urgently needed. This article analysis the major factors that could enable the ultimate success of cross-strait cooperation on fisheries issue in the South China Sea areas. In addition, a prudent stepwise approach and viable actions which the two sides should undertake to conserve and manage the fishery resources are also discussed. Finally, the article proposes a coordinative and cooperative mechanism for Mainland China and Taiwan towards the sustainable conservation and co-management of fishery resources in the South China Sea waters, as well as the sound measures for learning, exchanging and capacity building of the two sides.

Success in heading north?: South Korea's master plan for Arctic policy

Kim HJung. Success in heading north?: South Korea's master plan for Arctic policy. Marine Policy [Internet]. 2015 ;61:264 - 272. Available from: http://www.sciencedirect.com/science/article/pii/S0308597X15002213
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

South Korea's seven governmental ministries and agency jointly announced a “Master Plan for Arctic Policy” on December 10, 2013. This represents the state's first comprehensive Arctic policy document. This paper aims to analyze the Korean government's Master Plan from both the legal and policy perspectives, as well as to make constructive comments for its improvement. Environmental changes, the need for scientific research, growing economic optimism about the Arctic region, and political leadership have led South Korea to head north. These four factors form the basis for the Master Plan. This document outlines Korea's vision (to be a reliable and responsible partner in this polar region), three policy goals, four strategies, and thirty-one projects connected to the Arctic region. The formation of the Master Plan has been an opportunity for South Korea to organize and compile all the various Arctic activities independently conducted by governmental ministries and agency. In order to improve South Korea's Arctic policy since the Master Plan, the author recommends that the nation prioritize its projects according to its needs and the feasibility of each project. Prudence is required in the drafting and implementation of Arctic policy to respect Arctic states' sovereignties and sovereign rights over the Arctic areas. Finally, strengthening cooperation with the Arctic states and at Arctic forums is indispensable. In particular, bilateral cooperation is essential for South Korea to perform economic activities such as the exploration for oil and gas.

Managing catch of marine megafauna: Guidelines for setting limit reference points

K. Curtis A, Moore JE, Boyd C, Dillingham PW, Lewison RL, Taylor BL, James KC. Managing catch of marine megafauna: Guidelines for setting limit reference points. Marine Policy [Internet]. 2015 ;61:249 - 263. Available from: http://www.sciencedirect.com/science/article/pii/S0308597X15002031
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Limit reference points (LRPs) for catch, which correspond to thresholds to undesirable population or ecosystem states, offer a consistent, objective approach to management evaluation and prioritization across fisheries, species, and jurisdictions. LRPs have been applied successfully to manage catch of some marine megafauna (elasmobranchs, marine reptiles, seabirds, and marine mammals) in some jurisdictions, such as the use of Potential Biological Removal (PBR) to manage incidental mortality of marine mammals under the U.S. Marine Mammal Protection Act. However, implementation of ecosystem-based management is still in its infancy globally, and LRPs have not yet been widely adopted for marine megafauna, particularly for incidental catch. Here, guidelines are proposed for estimating catch LRPs for marine megafauna, with particular attention to resolving common technical and political challenges, including (1) identifying management units, population thresholds, and risk tolerances that align with common conservation goals and best practices, (2) choosing catch LRP estimators, (3) estimating input parameters such as abundance and productivity, (4) handling uncertainty, and (5) dealing with mismatches between management jurisdictions and population boundaries. The problem of cumulative impacts across sectors is briefly addressed. These guidelines, grounded in marine policy, science, precedent, and lessons learned, should facilitate wider application of catch LRPs in evaluation and management of fisheries impacts on marine megafauna, in support of global commitments to conserve biodiversity and manage fisheries responsibly.

The fisheries of Oman: A situation analysis

Belwal R, Belwal S, Jabri OAl. The fisheries of Oman: A situation analysis. Marine Policy [Internet]. 2015 ;61:237 - 248. Available from: http://www.sciencedirect.com/science/article/pii/S0308597X15002183
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

This research paper presents a situation analysis of artisanal fishermen on the Batinah coast of Oman, conducted within the scope of a project that had a broader mandate on training needs assessment (TNA). The collection of data followed a structured survey approach where the questionnaires were administered to 1934 fishermen and were analyzed by a mixed method approach. The findings were triangulated-from information gained from the observations of fishermen and the discussions held with other stakeholders. The research found that the majority of fishermen on the Batinah coast were not appropriately educated and trained. Most of them followed irregular routines, earned little money from fishing, had low savings, faced financial constraints, and lacked knowhow of modern fishing techniques and post-harvest dealings. The fishermen’s performance over several key variables revealed a need for a consolidated marine policy that takes into consideration a host of issues related to the governance of artisanal fisheries and its sustainability and contribution to the economic activities in Oman.

Diver towed GPS to estimate densities of a critically endangered fish

Lynch T, Green M, Davies C. Diver towed GPS to estimate densities of a critically endangered fish. Biological Conservation [Internet]. 2015 ;191:700 - 706. Available from: http://www.sciencedirect.com/science/article/pii/S0006320715300598
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Spotted handfish are a critically endangered anglerfish. Monitoring of the species has, in the past, been undertaken via underwater visual census (UVC) parameterised with fixed length 100 m × 3 m strip transects measured with reel lines. However, the sparse distribution and cryptic nature of handfish resulted in low statistical power to track populations through time. To achieve reasonable confidence of detecting change ~ 40 transects are required for density estimates, making the logistical constraints of monitoring onerous. We trialled a new survey method for UVC at one study site with a known local population of fish, replacing reel transects with variable length strip transects parameterised with a diver towed Global Positioning System (GPS) float. From 18 transects we determined a density of 24 (± 3.5) handfish per hectare, but bootstrapping suggested little improvement in precision occurred after 6 transects. Modelling these results to previous estimates at the site indicated that our GPS float approach required many fewer transects and dives to determine 50% increases or decreases in fish densities. This improvement was partly due to the better sampling efficiency; with 3 times the average search area per transect but was also a result of longer transects being a better solution for monitoring a sparse population. Our results returned a normal sample distribution of fish counts with few zeros and many multiple observations, which differed to the original approach which was heavily skewed towards zero observations per transect. However, at very low population densities even this more robust solution will require many samples to detect change. Our GPS parameterized surveys also improved the functionality of observing fish behaviour as we could accurately plot fish allowing for detailed investigation of distributions. When fish were observed they were also bi-laterally digitally photographed to record their unique natural markings. By synchronising the photographs timestamp with the GPS clock, we were able to geo-locate individual recaptures and our preliminary results suggests net movements were limited. This new approach increases the logistical feasibility for monitoring spotted handfish and may have applications for other sparsely distributed benthic species.

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