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There is broad evidence of climate change causing shifts in fish distribution worldwide, but less is known about the response of fisheries to these changes. Responses to climate‐driven shifts in a fishery may be constrained by existing management or institutional arrangements and technological settings. In order to understand how fisheries are responding to ocean warming, we investigate purse seine fleets targeting tropical tunas in the east Atlantic Ocean using effort and sea surface temperature anomaly (SSTA) data from 1991 to 2017. An analysis of the spatial change in effort using a centre of gravity approach and empirical orthogonal functions is used to assess the spatiotemporal changes in effort anomalies and investigate links to SSTA. Both analyses indicate that effort shifts southward from the equator, while no clear pattern is seen northward from the equator. Random forest models show that while technology and institutional settings better explain total effort, SSTA is playing a role when explaining the spatiotemporal changes of effort, together with management and international agreements. These results show the potential of management to minimize the impacts of climate change on fisheries activity. Our results provide guidance for improved understanding about how climate, management and governance interact in tropical tuna fisheries, with methods that are replicable and transferable. Future actions should take into account all these elements in order to plan successful adaptation. [ABSTRACT FROM AUTHOR]

Historical capture records of bluefin tuna ( Thunnus thynnus ; BFT hereafter) from the Gibraltar Strait and Western Mediterranean show pronounced short- and long-term fluctuations. Some of these fluctuations are believed to be associated with biological and ecological process, as well as distinct climate factors. For the period of study (1700–1936) of this work, we found a long-term increasing trend in the BFT captures and in the climate variables. After applying a statistical time series analysis of relevant climate variables and long-term tuna capture records, it is highlighted the role played by sea-surface temperature (SST) on bluefin population variations. The most relevant result of this study is the strong correlation found between the total solar irradiance (TSI) — an external component of the climate system — and bluefin captures. The solar irradiance could have affected storminess during the period under study, mainly during the time interval 1700–1810. We suggest physico-biological mechanisms that explain the BFT catch fluctuations in two consecutive time intervals. In the first period, from 1700 to 1810, this mechanism could be high storm and wind activity, which would have made the BFT fisheries activities more difficult by reducing their efficacy. In contrast, during the interval from 1810 to 1907, the effects of wind and storms could be on spawning behaviour and larval ecology, and hence on year class strength, rather than on fish or fisherman's behaviour. These findings open up a range of new lines of enquiry that are relevant for both, fisheries and climate change research. [ABSTRACT FROM AUTHOR]

Abstract: Gelidium corneum (Hudson) J.V. Lamouroux is a very important primary producer in the Cantabrian coastal ecosystem. Some local declines in their populations have been recently detected in the Basque coast. Occurrences of yellowing and an unusual branch breakdown pattern have also been reported for some G. corneum populations. In order to gain further insight into those environmental stressors operating at a local scale, here we investigate if shallow subtidal populations of G. corneum living under potentially different conditions of irradiance (PAR and UVA) and water temperature exhibit differences in some biochemical indicators of stress, namely C:N, antioxidant activity (radical cation of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate); ABTS+ assay) and mycosporine-like amino acids (MAAs) (Asterine 330 and Palythine). We hypothesised that G. corneum subjected to higher ambient levels of irradiance and water temperature would show higher C:N ratios, lower antioxidant activity and higher MAA concentrations. Our results partially support this hypothesis. We found that G. corneum exposed to increased levels of irradiance (PAR, UVA) exhibited greater C:N ratios and lower antioxidant activity (higher IC50), whereas no relationship was found regarding MAAs. No differences in biochemical performance in relation to temperature were detected among G. corneum exposed to comparable high light. Similarly, G. corneum growing under lower UVA radiation levels showed no differences in any of the measured biochemical variables with regard to PAR and water temperature. These findings suggest that, among the environmental factors examined, UVA radiation may be an important driver in regulating the along-shore variation in G. corneum biochemical performance. Therefore, the role of irradiance, especially UV radiation, in potential future alterations in Cantabrian G. corneum populations cannot be ruled out as a potential underlying factor. [Copyright &y& Elsevier]

An extensive sampling program was performed in the Atlantic side of the Iberian Peninsula on 17 sites during 2010 and 2011 summers, in order to characterize the distributional pattern of potential toxic dinoflagellates of the genus Ostreopsis. The study area presents a discontinuity in the species distribution in a pattern that parallels that of summer water temperature. Ostreopsis was not found in a relatively wide fringe of the Northwest side of the Peninsula, as water temperature is markedly lower than that in the Northeast and Southwest extremes where Ostreopsis has been found. Comparing the observed distribution of Ostreopsis on the Atlantic coast of the Peninsula with different sea surface temperature (SST) percentiles, it is notable that neither minimum nor maximum temperatures observed in the range of the study area can explain the species distribution but presumably is the length of the warm period what limits the genus presence. Thus we hypothesize that for Ostreopsis to be present in a certain area three continuous months with SST above 19.5°C may be necessary. [ABSTRACT FROM AUTHOR]

The Spanish surface fishery operates mainly during the summer season in the waters of the Bay of Biscay. Sea surface temperature (SST) data recovered from satellite images are being used to improve the operational efficiency of fishing vessels (e.g. reduce search time and increase catch rate) and to improve the understanding of the variations in catch distribution and rate needed to properly manage fisheries. The images used for retrieval of SST often present gaps due to the existence of clouds or satellite malfunction periods. The data gaps can totally or partially affect the area of interest. Within this study, an application of a technique for the reconstruction of missing data called DINEOF (data interpolating empirical orthogonal functions) is analysed, with the aim of testing its applicability in operational SST retrieval during summer months. In this case study, the Bay of Biscay is used as the target area. Three months of SST Moderate Resolution Imaging Spectroradiometer (MODIS) images, ranging from 1 May 2006 to 31 July 2006, were used. The main objective of this work is to test the overall performance of this technique, under potential operational use for the support of the fleet during the summer fishing season. The study is designed to analyse the sensitivity of the results of this technique to several details of the methodology used in the reconstruction of SST, such as the number of empirical orthogonal functions (EOFs) retained, the handling of the seasonal cycle or the length (number of images) of the SST database used. The results are tested against independent SST data from International Comprehensive Ocean-Atmosphere Data Set (ICOADS) ship reports and standing buoys and estimations of the error of the reconstructed SST fields are given. Conclusions show that over this area three months of data are enough for efficient SST reconstruction, which yields four EOFs as the optimal number needed for this case study. An extended EOF experiment with SST and SST with a lag of one day was carried out to analyse whether the autocorrelation of the SST data allows better performance in the SST reconstruction, although the experiment did not improve the results. The validation studies show that the reconstructed SSTs can be trusted, even when the amount of missing data is very high. The mean absolute deviation maps show that the error is greatest near to the coast and mainly in the upwelling areas close to the French and north-western Spanish coasts. [ABSTRACT FROM AUTHOR]

Burnt tuna (BT), or yake-niku, is a quality flaw of the muscle characterised by a pale colour and grainy and exudative texture. Cathepsin-L, water soluble and total protein components from normal and BT muscles, from three tropical tuna species – yellowfin (YFT, Thunnus albacares ), bigeye (BET, Thunnus obesus ) and skipjack (SKJ, Katsuwonus pelamis ) – were compared by electrophoretic and western blot analyses to identify biomarkers for BT. As expected, SDS–PAGE patterns were species-specific but differences, due to BT, were observed only between some low ionic strength extracts of BET and YFT. Protein oxidation and cell proliferation analysed by immunoblotting did not show differences between BT and normal muscles. Gelatine zymography revealed different gelatinase activity patterns that, although not linked to BT, may affect the final texture of the muscle. A 43 kDa band, identified as creatine kinase by proteomic analysis, showed the potential to be a good indicator for BT in BET and YFT. [ABSTRACT FROM AUTHOR]

Abstract: In Bilbao (Spain), an air quality network measures sulphur dioxide levels at 4 locations. The objective of this paper is to develop a practical methodology to identify redundant sensors and evaluate a network''s capability to correctly follow and represent SO2 fields in Bilbao, in the frame of a continuous network optimization process. The methodology is developed and tested at this particular location, but it is general enough to be useable at other places as well, since it is not tied neither to the particular geographical characteristics of the place nor to the phenomenology of the air quality over the area. To assess the spatial variability of SO2 measured at 4 locations in the area, three different techniques have been used: Self-Organizing Maps (SOMs), cluster analysis (CA) and Principal Component Analysis (PCA). The results show that the three techniques yield the same results, but the information obtained via PCA can be helpful not only for that purpose but also to throw light on the major mechanisms involved. This might be used in future network optimization stages. The main advantage of cluster analysis and SOMs is that they provide readily interpretable results. All the calculations have been carried out using the freely available software R. [Copyright &y& Elsevier]