scholarly journals Long-term patterns of mass stranding of the colonial cnidarian Velella velella: influence of environmental forcing

2021 ◽  
Vol 662 ◽  
pp. 69-83
Author(s):  
T Jones ◽  
JK Parrish ◽  
HK Burgess
Keyword(s):  
Pacific Northwest ◽  
Citizen Science ◽  
Small Sample Size ◽  
Current System ◽  
Information Criterion ◽  
Reporting Rate ◽  
Small Sample ◽  
Northern California ◽  
California Current System ◽  
Mass Stranding

Velella velella is a pleustonic cnidarian noted worldwide for mass stranding of the colonial phase. Utilizing a 20 yr dataset (2000-2019; 23265 surveys) collected by the COASST citizen science program, we examined the spatio-temporal occurrence of mass strandings of V. velella along the Pacific Northwest coast from Washington to northern California, USA. V. velella mass strandings were documented in 14 years, with expansive events in 2003-2006 and 2014-2019. Events predominantly occurred in spring and were synchronous (April) among years, concurrent with shifts to prevailing onshore winds. Autumn mass stranding events occurred infrequently, with no consistent phenology (2005: November; 2014: August). In stranding years, reports of V. velella were mostly synchronous throughout the surveyed area, and events consistently spanned >400 km of coastline, with highest reporting rates in the vicinity of the Columbia River plume, collectively suggesting extensive V. velella blooms throughout the northern California Current system in some years. Annual metrics of spring V. velella reporting rate (proportion of beaches; January-June) were modeled as a function of indices representing sea surface temperature anomaly (SSTa), easterly (onshore) wind speed, and regional upwelling. The best models (based on Akaike’s information criterion corrected for small sample size) indicated that SSTa averaged over the preceding winter (December-February) was positively correlated with spring reporting rate, suggesting that mass strandings of V. velella may be more prevalent in warmer years. As planetary warming continues, and V. velella strandings are easily recorded by citizen science programs globally, we suggest that stranding prevalence may be one relatively easy measure providing evidence for epipelagic ecosystem response.

scholarly journals Surface Stress and Atmospheric Boundary Layer Response to Mesoscale SST Structure in Coupled Simulations of the Northern California Current System

2019 ◽  
Vol 148 (1) ◽  
pp. 259-287
Author(s):  
R. M. Samelson ◽  
L. W. O’Neill ◽  
D. B. Chelton ◽  
E. D. Skyllingstad ◽  
P. L. Barbour ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Stress ◽  
Current System ◽  
California Current ◽  
Heat Fluxes ◽  
Neutral Stability ◽  
Northern California ◽  
Coupling Coefficients ◽  
California Current System ◽  
Northern California Current

Abstract The influence of mesoscale sea surface temperature (SST) variations on wind stress and boundary layer winds is examined from coupled ocean–atmosphere numerical simulations and satellite observations of the northern California Current System. Model coupling coefficients relating the divergence and curl of wind stress and wind to downwind and crosswind SST gradients are generally smaller than observed values and vary by a factor of 2 depending on planetary boundary layer (PBL) scheme, with values larger for smoothed fields on the 0.25° observational grid than for unsmoothed fields on the 12-km model grid. Divergence coefficients are larger than curl coefficients on the 0.25° grid but not on the model grid, consistent with stronger scale dependence for the divergence response than for curl in a spatial cross-spectral analysis. Coupling coefficients for 10-m equivalent neutral stability winds are 30%–50% larger than those for 10-m wind, implying a correlated effect of surface-layer stability variations. Crosswind surface air temperature and SST gradients are more strongly coupled than downwind gradients, while the opposite is true for downwind and crosswind heat flux and SST gradients. Midlevel boundary layer wind coupling coefficients show a reversed response relative to the surface that is predicted by an analytical model; a predicted second reversal with height is not seen in the simulations. The relative values of coupling coefficients are consistent with previous results for the same PBL schemes in the Agulhas Return Current region, but their magnitudes are smaller, likely because of the effect of mean wind on perturbation heat fluxes.

scholarly journals Fish mislabelling in France: substitution rates and retail types

2014 ◽  
Author(s):  
Julien Bénard-Capelle ◽  
Victoire Guillonneau ◽  
Claire Nouvian ◽  
Nicolas Fournier ◽  
Karine Le Loët ◽  
...  
Keyword(s):  
Natural Resources ◽  
Sample Size ◽  
Citizen Science ◽  
Substitution Rate ◽  
Small Sample Size ◽  
Bluefin Tuna ◽  
Small Sample ◽  
The Other ◽  
Species Substitution ◽  
Scientific Expertise

The development of citizen science has brought together scientific expertise and volunteer involvement to answer both scientific and societal questions. In this study, a consortium of citizens, journalist, scientists and non governmental organisations reports the first measure of the market-wide rate of fish mislabelling in France.We collected in fishmonger shops, supermarkets and restaurants and sequenced 390 samples of fish either in fillets or prepared meals, which is the largest dataset assembled to date in an European country.The overall substitution rate is one of the lowest observed for comparable surveys with large sampling in Europe. Remarkably, we detected no case of species mislabelling among the frozen fillets or in industrially prepared meals. We also investigated most of the mislabelling cases detected directly from the sellers. A number of them admitted that the substitution took place at the end of the supply chain.The rate of mislabelling does not differ between species (3.7 %, ci 2.2-6.4%), except for bluefin tuna. Despite a very small sample size (n=6), this species stands in sharp contrast with the low substitution rate observed for the other species (rate between 36 and 99%). This study shows that even in countries where species substitution rate is low, citizen science can enhance the management of natural resources and provide important insights for regulation policies.

Corrigendum to “Large-scale bloom of Akashiwo sanguinea in the Northern California current system in 2009” [Harmful Algae 37 (2014) 38–46]

Harmful Algae ◽  
2015 ◽  
Vol 44 ◽  
pp. 63
Author(s):  
Angelicque E. White ◽  
Katie S. Watkins-Brandt ◽  
S. Morgaine McKibben ◽  
A. Michelle Wood ◽  
Matthew Hunter ◽  
...  
Keyword(s):  
Large Scale ◽  
Current System ◽  
California Current ◽  
Harmful Algae ◽  
Northern California ◽  
California Current System ◽  
Northern California Current ◽  
Akashiwo Sanguinea
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