Applications of sensory biology in marine ecology and aquaculture

Journal homepage: http://www.int-res.com/journals/meps

The peer review process: perspectives and insights from a journal editor

Ever-increasing numbers of manuscripts, grant proposals, working group documents, position papers, etc. are being circulated – to an overburdened community of non-remunerated experts – for critical evaluation. Expert reviewers are fatigued. Their efforts, and particularly the amount of time required to prepare complete, well-considered and constructive critiques, are unrecognized by administrators. As a result, the peer review process is in danger of collapse. More and more colleagues are no longer able or willing to accept review assignments. I will discuss these, and related issues, from my perspective as Associate Editor-in-Chief of Marine Ecology Progress Series (MEPS). In 2007, MEPS, L&O, CJFAS and the ICES JMS will receive > 3000 manuscripts for evaluation. At least 2000 of these will be distributed for review, and some of them will be resubmitted and reviewed again. This will require approximately 10 000 reviews. With current rates of rejection, at least 1500 of these manuscripts will likely be resubmitted to other journals, which will solicit perhaps 3000–4000 more reviews. Some of those will be rejected, and resubmitted elsewhere. Thus, manuscripts initially submitted to only 4 marine science journals could easily require more than 15 000 reviews. And how many qualified experts are there out there anyways?! These numbers, and the level of non-remunerated time and effort that they represent, are meant to be sobering and will hopefully serve as the basis for an animated discussion. Keywords: peer review; quality control; inherent bias; reviewer fatigu

Marine Protected Areas as a central element of ecosystem-based management: defining their location, size and number

Journal homepage: http://www.int-res.com/journals/meps

Denialism and muddying the water or organized skepticism and clarity? THAT is the question

The research being commented on here has been criticized and defended in journals. Sneddon et al. (2018) add nothing substantive. We have nothing further to add. Readers are referred to Diggles (2018) and to Browman et al. (2018) for a detailed assessment

Developing the knowledge base needed to sustainably manage mesopelagic resources

Recent estimates suggest that the mesopelagic zone could contain a total fish biomass of 2-19.5 gigatonnes, roughly equivalent to 100 times the annual catch of all existing fisheries. In addition to the possibility of direct consumption of mesopelagic species, there is interest in their use for fishmeal, as a source of dietary supplements for humans, and to bio-prospect pharmaceuticals. All of this, and the demands for a global food supply that can feed an ever-growing population, has driven interest in the mesopelagic. Thus, accurate quantification of the biomass of mesopelagic resources, their nutritional and genetic composition, their links to other components of the food web, to other oceanic realms and to biological and chemical oceanographic processes and cycles, are the focus of growing research activity. This information is needed to ensure the sustainable management of these resources. In this introduction, we summarize the contributions included in this theme set and provide some “food for thought” on the state-of-the-art in research on the mesopelagic, including identifying the knowledge that must be generated to support its sustainable management (e.g. the effect that extracting significant biomass might have on the pelagic ecosystem and the flow of material and energy through it

The three-dimensional prey field of the northern krill, Meganyctiphanes norvegica, and the escape responses of their copepod prey

In the north Atlantic, Meganyctiphanes norvegica feeds predominantly on copepods, including Calanus spp. To quantify its perceptual field for prey, and the sensory systems underlying prey detection, the responses of tethered krill to free-swimming Calanus spp. were observed in 3D using silhouette video imaging. An attack–which occurred despite the krill’s being tethered—was characterized by a pronounced movement of the krill’s antennae towards the target, followed by a propulsion and opening of the feeding basket. Frequency distributions of prey detection distances were significantly different in the light vs. the dark, with median values of 26.5 mm and 19.5 mm, respectively. There were no significant differences in the angles at which prey were detected by krill (relative to the predator’s longitudinal body axis) in the light vs. the dark. Prey detections were symmetrically distributed on either side of the predator, in both light and dark. However, significant asymmetry was found in the dorsal–ventral direction with 80% of the prey detections located below the midline of the krill’s body axis and, given the placement and orientation of the compound eyes, presumably outside its visual field of view. This indicates that, at least under these conditions, vision was not the main sensory modality involved in the detection of active prey by M. norvegica. However, under some circumstances, vision may provide supplemental information. Avoidance responses of copepod prey were nearly twice the velocity of their nominal background swimming speed (153 ± 48 and 85 ± 75 mm s−1, respectively), on average taking them 43 ± 16 mm away from the predator. This is far beyond the krill’s perceptual range, suggesting that the escape reaction provides an effective deterrent to predation (although perhaps less so for free-swimming krill). This information can be used to parameterize models that assess the role of krill as predators in marine ecosystems

Light Primes the Escape Response of the Calanoid Copepod, Calanus finmarchicus

The timing and magnitude of an escape reaction is often the determining factor governing a copepod’s success at avoiding predation. Copepods initiate rapid and directed escapes in response to fluid signals created by predators; however little is known about how copepods modulate their behavior in response to additional sensory input. This study investigates the effect of light level on the escape behavior of Calanus finmarchicus. A siphon flow was used to generate a consistent fluid signal and the behavioral threshold and magnitude of the escape response was quantified in the dark and in the light. The results show that C. finmarchicus initiated their escape reaction further from the siphon and traveled with greater speed in the light than in the dark. However, no difference was found in the escape distance. These results suggest that copepods use information derived from multiple sensory inputs to modulate the sensitivity and strength of the escape in response to an increase risk of predation. Population and IBM models that predict optimal vertical distributions of copepods in response to visual predators need to consider changes in the copepod's behavioral thresholds when predicting predation risk within the water column

Debating the effectiveness of marine protected areas

Increasing the size and number of marine protected areas (MPAs) is widely seen as a way to meet ambitious biodiversity and sustainable development goals. Yet, debate still exists on the effectiveness of MPAs in achieving ecological and societal objectives. Although the literature provides significant evidence of the ecological effects of MPAs within their boundaries, much remains to be learned about the ecological and social effects of MPAs on regional and seascape scales. Key to improving the effectiveness of MPAs, and ensuring that they achieve desired outcomes, will be better monitoring that includes ecological and social data collected inside and outside of MPAs. This can lead to more conclusive evidence about what is working, what is not, and why. Eight authors were asked to write about their experiences with MPA effectiveness. The authors were instructed to clearly define “effectiveness” and discuss the degree to which they felt MPAs had achieved or failed to be effective. Essays were exchanged among authors and each was invited to write a shorter “counterpoint.” The exercise shows that, while experiences are diverse, many authors found common ground regarding the role of MPAs in achieving conservation targets. This exchange of perspectives is intended to promote reflection, analysis, and dialogue as a means for improving MPA design, assessment, and integration with other conservation tools

Artsfordeling og bestandsstørrelser for de ulike artene av leppefisk i de undersøkte områdene

Sammensetningen av leppefiskarter er signifikant forskjellige mellom alle lokalitetene som ble undersøkt, også mellom lokaliteter som ligger nær hverandre. De dominerende artene var grønngylt og bergnebb alle steder foruten Smøla som bare hadde bergnebb i fangstene. Grønngylt hadde større gjenfangstfrekvens enn bergnebb på alle lokalitetene dette ble målt foruten de to Tysnes – lokalitetene. Der var det ingen signifikante forskjeller mellom disse to artene

Impact of ultraviolet radiation on marine crustacean zooplankton and ichthyoplankton: a synthesis of results from the estuary and Gulf of St. Lawrence, Canada

The objectives of the research program reported upon here were (1) to measure ambient levels of UV radiation and determine whichvariables most strongly affected its attenuation in the waters of the estuary and Gulf of St. Lawrence, Canada; and (2) to investigate the potential direct impacts of W radiation on species of crustacean zooplankton and fish whose early life stages are planktonic. In this geographic region, productivity-determining biophysical interactions occur in the upper 0 to 30 m of the water column. Measurements of the diffuse attenuation coefficients for ultraviolet-B radiation (W-B, 280 to 320 nm) at various locations in this region indicated maximum 10% depths (the depth to which 10% of the surface energy penetrates at a given wavelength) of 3 to 4 m at a wavelength of 310 nm. Organisms residing in this layer-including the eggs and larvae of Calanus finmarchicus and Atlantic cod Gadus morhua-are exposed to biologically damaging levels of W radiation. As a result of these physical and biological characteristics, this system offered a relevant opportunity to assess the impacts of UV on subarctic marine ecosystems. Eggs of C. finmarchicus were incubated under the sun, with and without the W-B and/or UV-A (320 to 400 nm) wavebands. W-exposed eggs exhibited low percent hatchmg compared to those protected from W : W radiation had a strong negative impact on C. finmarchicus eggs. Further, percent hatching in W-B-exposed eggs was not significantly lower than that in eggs exposed to UV-A only: under natural sunlight, UV-A radiation appeared to be more detrimental to C. finmarchicus embryos than was UV-B. In analogous experiments with Atlantic cod eggs, exposure to UV-B produced a significant negative effect. However, UV-A had no negative effect on cod eggs. Additional experiments using a solar simulator (SS) revealed high wavelength-dependent mortality in both C. finmarchicus and cod embryos exposed to UV. The strongest effects occurred under exposures to wavelengths below 312 nm. At the shorter wavelengths (<305 nm) UV-B-induced mortality was strongly dose-dependent, but (for both C. finmarchicus and cod) not significantly influenced by dose-rate. Thus, at least within the limits of the exposures under which the biological weighting functions (BWFs) were generated, reciprocity held. The BWFs derived for UV-B-induced mortality in C. finmarchicus and cod eggs were similar in shape to the action spectrum for UV-B effects on naked DNA. Further, the wavelengthdependence of DNA damage was similar to that for the mortality effect. These observations suggest that W-induced mortality in C. finmarchicus and cod eggs is a direct result of DNA damage. There was no evidence of a detrimental effect of UV-A radiation in these SS-derived results. A mathematical model that includes the BWFs, vertical mixing of eggs, meteorological and hydrographic conditions, and ozone depletion, indicates that W-induced mortality in the C. finmarchicus egg population could be as high as 32.5 %, while the impact on the cod egg population was no more than 1.2%. Variability in cloud cover, water transparency (and the variables that affect it), and vertical distribution and displacement of planktonic organisms within the mixed layer can all have a greater effect on the flux of UV-B radiation to which they are exposed than will ozone layer depletion at these latitudes. Our observations indicate that C, finmarchicus and cod eggs present in the first meter of the water column (likely only a small percentage of the total egg populations) are susceptible to W radiation. However, although exposure to UV can negatively impact crustacean zooplankton and ichthyoplankton populations, these direct effects are likely minimal within the context of all the other environmental factors that produce the very high levels of mortality typically observed in their planktonic early life stages. The impact of indnect effects-which may well be of much greater import-has yet to be evaluated