Do western Atlantic bluefin tuna spawn outside of the Gulf of Mexico? Results from a larval survey in the Atlantic Ocean in 2013

In 2013, a larval survey was conducted north and east of the Bahamas aboard the NOAA Ship NANCY FOSTER. Sampling areas were selected based on larval habitat model predictions, and daily satellite analysis of surface temperature and ocean color. Samples were collected at 97 stations, and 18 larval BFT (Thunnus thynnus) were found at 9 stations. Six of these stations came from oceanographically complex regions characterized by cyclonic and anticyclonic gyres. Larvae ranged in size from 3.22mm to 7.58 mm, corresponding to approximately 5-12 days in age. Analysis of satellite derived surface currents and CTD data suggest that these larvae were spawned and retained in this area. Larval habitat models show areas of high predicted abundance extending east to 650 W, but the actual extent of spawning in this area remains unknown.En prens

Effect of mesoscale eddies and chlorophyll on larval fish assemblages in the Gulf of Mexico: implications for atlantic bluefin tuna (Thunnus thynnus)

2012 Ocean Sciences Meeting, 20-24 February 2012, Salt Lake City, Utah, USAIt is widely known that eddies and their attendant fronts play an important role in oceanic biological processes and may constitute a unique pelagic habitat for larvae. Previous studies that we conducted in the Gulf of Mexico (GOM) region showed that the variability in the Loop Current and anticyclonic ring field was reflected on the larval fish distribution of some species, likely associated to the boundaries of the latter features. To date, however, there has been only very limited studies in the region using satellite data to assess the influence of smaller mesoscale features on larvae assemblages. Our primary goal in this study is to explore the effect of the divergence and convergence associated to cyclonic and anticyclonic eddies on the complex variability of larval fish assemblages in the northern GOM. To complement visual eddy detection techniques, we use the footprint that cyclonic and anticyclonic eddies leave in sea surface height, temperature, and chlorophyll a, basically by analyzing satellite altimetry fields and applying the Okubo-Weiss parameterPeer reviewe

Comparison between environmental characteristics of larval bluefin tuna Thunnus thynnus habitat in the Gulf of Mexico and western Mediterranean Sea

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Comparing environmental characteristics of larval bluefin tuna (Thunnus thynnus) habitat in the Gulf of Mexico and western Mediterranean Sea

Atlantic bluefin tuna undertake long migrations to reach warm, low productivity spawning grounds in the Gulf of Mexico and Mediterranean Sea. Peak spawning occurs during spring in the Gulf of Mexico, and summer in the Mediterranean. Environmental conditions within spawning areas appear unfavorable for adult feeding and physiology, and so have been presumed to benefit larval survival, through enhanced feeding conditions, larval retention or growth rates. In this study, a comparison of the environmental characteristics of both spawning sites was completed using standardized environmental data and modeling methods. Artificial neural network predictive models of larval occurrence were constructed using historical larval collections, and environmental variables from both in situ and remotely sensed sources. Results showed that larvae on both spawning grounds were most likely to be found in warm (23-28°C), low chlorophyll waters with moderate current velocities, and favorable regional retention conditions. In the Gulf of Mexico, larvae were located in offshore waters outside of the Loop Current and warm eddies, while in the western Mediterranean, larval occurrences were associated with the confluence of inflowing Atlantic waters and saltier resident surface waters. Results suggested common themes within preferred spawning grounds on both sides of the Atlantic Ocean. However, the ecological processes governing larval survival and eventual recruitment are yet to be fully understoo

Digital work: self-branding and social capital in the freelance knowledge economy

Existing research shows that self-branding in the knowledge economy is a key promotional device for the pursuit of self-realization in a context that reifies entrepreneurialism as the main ideological stance. However, there is still reluctance to fully acknowledge the processes of sociality that constitute self-branding practice. While the relationship between branding and the affective dynamics of social production of value fostered by the diffusion of Web 2.0 is widely acknowledged in the literature, there still seems to be a lack of understanding of the extent to which self-branding relates to social relationships in the production of socialized value for individuals. The study of self- branding practices across digital freelance professions in the knowledge economy reveals how social media has come to represent a working tool that serves the curation of a professional image and the management of social relationships via the enactment of performative practices of sociality, which exist around a shared notion of reputation as value. Here, self-branding becomes an investment in social relationships with expected return for the acquisition of a reputation. This substantially equates self-branding with what social theory calls social capital, being instrumental to secure employment in the freelance-based labour market of the digital knowledge economy