The creation of the Chagos marine protected area: a fisheries perspective(☆).

From a fisheries perspective, the declaration of a 640,000 km² "no-take" Marine Protected Area (MPA) in the Chagos Archipelago in 2010 was preceded by inadequate consideration of the scientific rationale for protection. The entire area was already a highly regulated zone which had been subject to a well-managed fisheries licensing system. The island of Diego Garcia, the only area where there is evidence of overfishing has, because of its military base, been excluded from the MPA. The no-take mandate removes the primary source of sustenance and economic sustainability of any inhabitants, thus effectively preventing the return of the original residents who were removed for political reasons in the 1960s and 1970s. The principles of natural resource conservation and use have been further distorted by forcing offshore fishing effort to other less well-managed areas where it will have a greater negative impact on the well-being of the species that were claimed to be one of the primary beneficiaries of the declaration. A failure to engage stakeholders has resulted in challenges in both the English courts and before an international tribunal.

Diverging strategies to planning an ecologically coherent network of MPAs in the North Sea: the roles of advocacy, evidence and pragmatism in the face of uncertainty.

The North Sea is one of the most economically important seas in the world due to productive fisheries, extensive oil and gas fields, busy shipping routes, marine renewable energy development and recreational activity. Unsurprisingly, therefore, the use of marine protected areas (here defined widely to include fisheries closed areas and no-take marine reserves) in its management has generated considerable controversy-particularly with regards to the design of a regional ecologically coherent MPA network to meet international obligations. Drawing on three MPA processes currently occurring in the UK North Sea, we examine the real-world problems that make the designation of MPA networks challenging. The political problems include: disagreement among (and within) sectors over policy objectives and priorities, common access to fisheries resources at the EU level increasing the scale at which decisions have to be made and lack of an integrated strategy for implementing protected areas in the North Sea. The scientific problems include the patchy knowledge of benthic assemblages, limited knowledge of fishing gear-habitat interactions, and the increased risk of unforeseen externalities if human activity (predominantly fishing) is displaced from newly protected sites. Diverging stakeholder attitudes to these problems means that there is no consensus on what ecological coherence actually means. Ultimately, we caution against 'quick-fix' solutions that are based on advocacy and targets, as they create confusion and undermine trust in the planning process. We argue for a more pragmatic approach to marine protection that embraces the complexity of the social and political arena in which decisions are made.

The reniform reflecting superposition compound eyes of Nephrops norvegicus: optics, susceptibility to light-induced damage, electrophysiology and a ray tracing model.

The large reniform eyes of the reptant, tube-dwelling decapod Nephrops norvegicus are described in detail. Optically these reflecting superposition compound eyes are a little unusual in that they are laterally flattened, a feature that may enhance their sensitivity in that region, albeit at the expense of resolution. Electrophysiological and anatomical investigations suggest that the eyes are tuned to appropriate spectral and temporal sensitivities in the long and short term through movement of proximal pigments and possibly rhabdom adaptation. Although exposure to ambient surface light intensities is shown to cause damage to the retinal layer, especially in deeper living animals, there is no evidence yet that demonstrates an impact of eye damage on their survival. It is suggested that experimentation on marine decapods, with sensitive eyes, requires that particular attention is paid to their light environment.

Nephrops fisheries in European waters.

This review focuses on the Norway lobster (Nephrops norvegicus) as a resource, describing how the fishery has developed from the 1960s to the present day to become one of the most economically important fisheries in Europe. In 2010, the total landings were 66,500 tonnes, of which UK fishers landed a significant part (58.1%). The Nephrops fishery is also important for countries such as Ireland (11.7% of the total) and Sweden (1.9%) where it is of regional importance. Some are also taken in the Mediterranean, where Italian, Spanish and Greek fishers together take approximately 7% of the total landing. More than 95% of Nephrops are taken using single- or multi-rig trawlers targeting Nephrops or in mixed species fisheries. In regions such as Western Scotland and the Swedish West Coast, creel fisheries account for up to a quarter of the total landings. Across the range, a small proportion (<5%) is taken using traps in a fishery characterised by larger sized animals that gain a higher price and have lower discard and by-catches of ground fish with low mortalities. The trawling sector, however, is reducing the by-catches of ground fish with the aid of technical measures, such as square-mesh panels and grids and national systems of incentives. Assessments for Nephrops are operated via the 34 functional units (FUs) regarded as stocks. Changes in management procedures have arisen as a result of the advisory input from underwater TV fishery-independent stock surveys. The total allowable catch does not follow FUs but is agreed upon per management area.

DNA metabarcoding reveals the dietary profiles of a benthic marine crustacean, Nephrops norvegicus.

Norwegian lobster, Nephrops norvegicus, are a generalist scavenger and predator capable of short foraging excursions but can also suspension feed. Existing knowledge about their diet relies on a combination of methods including morphology-based stomach content analysis and stable isotopes, which often lack the resolution to distinguish prey items to species level particularly in species that thoroughly masticate their prey. DNA metabarcoding overcomes many of the challenges associated with traditional methods and it is an attractive approach to study the dietary profiles of animals. Here, we present the diet of the commercially valuable Nephrops norvegicus using DNA metabarcoding of gut contents. Despite difficulties associated with host amplification, our cytochrome oxidase I (COI) molecular assay successfully achieves higher resolution information than traditional approaches. We detected taxa that were likely consumed during different feeding strategies. Dinoflagellata, Chlorophyta and Bacillariophyta accounted for almost 50% of the prey items consumed, and are associated with suspension feeding, while fish with high fisheries discard rates were detected which are linked to active foraging. In addition, we were able to characterise biodiversity patterns by considering Nephrops as natural samplers, as well as detecting parasitic dinoflagellates (e.g., Hematodinium sp.), which are known to influence burrow related behaviour in infected individuals in over 50% of the samples. The metabarcoding data presented here greatly enhances a better understanding of a species' ecological role and could be applied as a routine procedure in future studies for proper consideration in the management and decision-making of fisheries.

Can a key boreal Calanus copepod species now complete its life-cycle in the Arctic? Evidence and implications for Arctic food-webs.

The changing Arctic environment is affecting zooplankton that support its abundant wildlife. We examined how these changes are influencing a key zooplankton species, Calanus finmarchicus, principally found in the North Atlantic but expatriated to the Arctic. Close to the ice-edge in the Fram Strait, we identified areas that, since the 1980s, are increasingly favourable to C. finmarchicus. Field-sampling revealed part of the population there to be capable of amassing enough reserves to overwinter. Early developmental stages were also present in early summer, suggesting successful local recruitment. This extension to suitable C. finmarchicus habitat is most likely facilitated by the long-term retreat of the ice-edge, allowing phytoplankton to bloom earlier and for longer and through higher temperatures increasing copepod developmental rates. The increased capacity for this species to complete its life-cycle and prosper in the Fram Strait can change community structure, with large consequences to regional food-webs.

Laboratory-based observations of behaviour in Northern krill (Meganyctiphanes norvegica Sars).

The behaviour of planktonic animals remains poorly understood due to the difficulty of observing them in situ without influencing their behaviour. Here we review experiments on the behavioural responses of Northern krill, Meganyctiphanes norvegica (and related organisms), in isolation in laboratory-based aquaria. The value of this approach lies in the close observation that is possible; the downside is the uncertainty as to how well the observed behaviour relates to the natural behaviour of the subject animal. We discuss studies of swimming and swarming, and the responses of krill to light. We consider techniques involving automatic recordings that avoid, to some extent, making subjective decisions on behaviour. The effects of isolation of such a gregarious animal and of exposure to unnaturally high light levels are also considered. We conclude that such experiments can be of great value as long as these limiting factors are addressed.

Insights into the morphology of symbiotic shrimp eyes (Crustacea, Decapoda, Palaemonidae); the effects of habitat demands.

Morphometric differences in the optical morphology of symbiotic palaemonid shrimps can be observed among species symbiotic with different host organisms. Discriminant functional analysis revealed three distinct groups within the species examined. Of these, bivalve symbionts appear to have an eye design that is solely unique to this host-symbiont grouping, a design that spans across multiple genera of phylogenetically unrelated animals. Although some taxonomic effects may be evident, this does not explain the difference and similarities in eye morphology that are seen within these shrimps. Therefore evolutionary pressures from their host environments are having an impact on the optical morphology of their eyes however, as indicated by host-hopping events there ecological adaptations occur post host invasion.

Artificial reefs and marine protected areas: a study in willingness to pay to access Folkestone Marine Reserve, Barbados, West Indies.

Artificial reefs in marine protected areas provide additional habitat for biodiversity viewing, and therefore may offer an innovative management solution for managing for coral reef recovery and resilience. Marine park user fees can generate revenue to help manage and maintain natural and artificial reefs. Using a stated preference survey, this study investigates the present consumer surplus associated with visitor use of a marine protected area in Barbados. Two hypothetical markets were presented to differentiate between respondents use values of either: (a) natural reefs within the marine reserve or (b) artificial reef habitat for recreational enhancement. Information was also collected on visitors' perceptions of artificial reefs, reef material preferences and reef conservation awareness. From a sample of 250 visitors on snorkel trips, we estimate a mean willingness to pay of US$18.33 (median-US$15) for natural reef use and a mean value of US$17.58 (median-US$12.50) for artificial reef use. The number of marine species viewed, age of respondent, familiarity with the Folkestone Marine Reserve and level of environmental concern were statistically significant in influencing willingness to pay. Regression analyses indicate visitors are willing to pay a significant amount to view marine life, especially turtles. Our results suggest that user fees could provide a considerable source of income to aid reef conservation in Barbados. In addition, the substantial use value reported for artificial reefs indicates a reef substitution policy may be supported by visitors to the Folkestone Marine Reserve. We discuss our findings and highlight directions for future research that include the need to collect data to establish visitors' non-use values to fund reef management.

External morphology of eyes and Nebenaugen of caridean decapods-ecological and systematic considerations.

Most caridean decapods have compound eyes of the reflecting superposition kind, and additionally some possess an accessory eye-like organ of unknown function, also referred to as the nebenauge. We examined 308 caridean genera to assess the general morphology of the eye, rostrum length, eye diameter and the presence or absence and, when present, the diameter of the nebenauge. We have attempted to relate these data to ecological and taxonomic considerations. We consider there to be 6 distinct eye types based on the margin between the eyestalk and cornea. The presence of nebenaugen appears to be generally linked to an active lifestyle, as evidenced by the fact that species that have nebenaugen tend to have larger eyes and are more likely to have a distinct rostrum. We suggest that the inconsistencies in its presence/absence under both systematic and ecological lenses may indicate that when present it has various roles relating to behavioural and physiological rhythms.

Preliminary observations on the mandibles of palaemonoid shrimp (Crustacea: Decapoda: Caridea: Palaemonoidea).

The mandibles of caridean shrimps have been widely studied in the taxonomy and functional biology of the group. Within the Palaemonoidea the mandibles reach a high level of structural diversity reflecting the diverse lifestyles within the superfamily. However, the majority of studies have been restricted to light microscopy, with the ultrastructure at finer levels poorly known. This study investigates the mandible of nine species belonging to six of the recognised families of the Palaemonoidea using SEM and analyses the results in a phylogenetic and dietary framework. The results of the study indicate that little phylogenetic information is conveyed by the structure of the mandible, but that its form is influenced by primary food sources of each species. With the exception of Anchistioides antiguensis, all species examined possessed cuticular structures at the distal end of the pars molaris (molar process). Five types of cuticular structures are recognised herein, each with a unique form, but variable in number, placement and arrangement. Each type is presumed to have a different function which is likewise related to diet.

Linking eye design with host symbiont relationships in pontoniine shrimps (Crustacea, Decapoda, Palaemonidae).

Symbiosis is prevalent in the marine environment with many studies examining the effects of such interactions between host and symbiont. Pontoniine shrimps are a group whose ecology is characterised by symbiotic interactions. This investigation examines the gross morphology of Pontoniinae compound eyes and superficial optical parameters with reference to their symbiotic relationship or lifestyle category; free-living, ectosymbiont, endosymbiont (bivalves) or endosymbiont (non-bivalves). The eye morphologies of free-living and ectosymbiotic species are very similar, yet differ from both forms of endosymbiotic species. Endosymbionts have significantly smaller and simpler eyes with larger facets and bigger interommatidial angles and eye parameters for increased sensitivity levels. However bivalve endosymbionts form an intermediary group between non-bivalve endosymbionts and ectosymbionts as a result of their more active lifestyle. The accessory eye or "nebenauge", although of uncertain function, commonly occurs in free-living Pontoniinae species but rarely in endosymbionts apart from in more primitive species. The variation in morphology reflects tensions between functional requirements and ecological pressures that have strongly influenced eye design in Pontoniinae.

The relationship between diver experience levels and perceptions of attractiveness of artificial reefs - examination of a potential management tool.

Artificial reefs are increasingly used worldwide as a method for managing recreational diving since they have the potential to satisfy both conservation goals and economic interests. In order to help maximize their utility, further information is needed to drive the design of stimulating resources for scuba divers. We used a questionnaire survey to explore divers' perceptions of artificial reefs in Barbados. In addition, we examined reef resource substitution behaviour among scuba divers. Divers expressed a clear preference for large shipwrecks or sunken vessels that provided a themed diving experience. Motives for diving on artificial reefs were varied, but were dominated by the chance of viewing concentrated marine life, increased photographic opportunities, and the guarantee of a 'good dive'. Satisfaction with artificial reef diving was high amongst novices and declined with increasing experience. Experienced divers had an overwhelming preference for natural reefs. As a management strategy, our results emphasize the capacity of well designed artificial reefs to contribute towards the management of coral reef diving sites and highlight a number of important areas for future research. Suggested work should validate the present findings in different marine tourism settings and ascertain support of artificial reefs in relationship to level of diver specialization.