Influence of abiotic factors in the biomass of deep water shrimps, P. longirostris and A. antennatus, off Catalano-Levantine Mediterranean coast of Spain.

Deep-water shrimps show large inter-annual fluctuations in biomass. We analysed the influence of some abiotic factors in these fluctuations using survey data (2006-2009). While P. longirostris biomass was feebly affected by the T-S of the water masses, these factors, particularly salinity, seemed to have a significant effect on A. antennatus a species considered to be stenothermal and stenohaline, whose biomass distribution showed a direct relationship with the Levantine Intermediate Water

On the presence of Heterocarpus ensifer Milne Edwards, 1881 (Decapoda, Pandalidae) in the Spanish Mediterranean

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Demersal assemblages on the soft bottoms off the Catalan-Levante coast of the Spanish Mediterranean

Publicado

Resilience dynamics and productivity-driven shifts in the marine communities of the Western Mediterranean Sea

Ecological resilience has become a conceptual cornerstone bridging ecological processes to conservation needs. Global change is increasingly associated with local changes in environmental conditions that can cause abrupt ecosystem reorganizations attending to system-specific resilience fluctuations with time (i.e. resilience dynamics). Here we assess resilience dynamics associated with climate-driven ecosystems transitions, expressed as changes in the relevant contribution of species with different life-history strategies, in two benthopelagic systems. We analysed data from 1994 to 2019 coming from a scientific bottom trawl survey in two environmentally contrasting ecosystems in the Western Mediterranean Sea—Northern Spain and Alboran Sea. Benthopelagic species were categorized according to their life-history strategies (opportunistic, periodic and equilibrium), ecosystem functions and habitats. We implemented an Integrated Resilience Assessment (IRA) to elucidate the response mechanism of the studied ecosystems to several candidate environmental stressors and quantify the ecosystems’ resilience. We demonstrate that both ecosystems responded discontinuously to changes in chlorophyll-a concentration more than any other stressor. The response in Northern Spain indicated a more overarching regime shift than in the Alboran Sea. Opportunistic fish were unfavoured in both ecosystems in the recent periods, while invertebrate species of short life cycle were generally favoured, particularly benthic species in the Alboran Sea. The study illustrates that the resilience dynamics of the two ecosystems were mostly associated with fluctuating productivity, but subtle and long-term effects from sea warming and fishing reduction were also discernible. Such dynamics are typical of systems with wide environmental gradient such as the Northern Spain, as well as systems with highly hydrodynamic and of biogeographical complexity such as the Alboran Sea. We stress that management should become more adaptive by utilizing the knowledge on the systems’ productivity thresholds and underlying shifts to help anticipate both short-term/less predictable events and long-term/expected effects of climate change.En prensa2,27

Inter-calibration trials between the R/V Cornide de Saavedra and the R/V Miguel Oliver in bottom trawl surveys off the Spanish coast

Bottom trawl surveys are conducted by the Spanish Oceanographic Institute (IEO) to provide information independent from the fisheries of commercial stocks: DEMERSALES in the northern Spanish Shelf, ARSA in the Gulf of Cadiz and MEDITS in the Mediterranean Shelf since 1983, 1993 and 1994, respectively. Surveys have been performed annually on board the R/V Cornide de Saavedra until 2013. This vessel (67 m, 1133 GRT) was built in 1972 and nowadays has been replaced by the new R/V Miguel Oliver (70 m, 2495 GRT). To guarantee the continuity between the two vessels of the abundance and biomass indices of the main target species and their length distributions, inter-calibration experiments have been performed for each of the three bottom trawl surveys. The goal of the inter-calibration between both vessels was to establish the most similar fishing conditions to detect and isolate if there was a vessel effect that caused different results in catches. And in if those differences were significant, to estimate calibration coefficients to homogenize abundance and biomass indices of the new vessel R/V Miguel Oliver with respect to the time series built with the old R/V Cornide de Saavedra. The inter-calibration experiment consisted in performing parallel tows with both vessels, using the same gear, and carrying out hauls of the same duration and speed. The parallel surveys in the V/R Cornide de Saavedra and the R/V Miguel Oliver followed the surveys protocols of IBTS for the northern Spain and Gulf of Cadiz and MEDITS for the Mediterranean. A total of 60 paired hauls were completed in the DEMERSALES survey, 43 for the ARSA and 37 hauls in the MEDITS. Comparisons between both vessels were done in each survey addressing: gear performance, total catch, commercial species catches, length distributions of the most representative species and analyzing the faunal fish assemblages detected. Differences between vessels were less significant for the DEMERSALES survey, with the higher catches, number of hauls and less variability; in the Gulf of Cadiz, catches of flatfish and some species of cephalopods were slightly higher in the R/V Miguel Oliver but no significant differences in the length distributions were found; for the MEDITS survey, catches by haul were lower, presenting a great diversity of species, thus complicating to separate the sources of variability due to the change of vessel from the uncertainty associated to the hauls. In general, catches in the R/V Miguel Oliver are similar to catches in the R/V Cornide de Saavedra. To verify the continuity and congruence of the time series special attention must be paid to the new surveys in the R/V Miguel Oliver to test if inter-calibration factors are needed for some species

Biology (growth and reproduction) of the Mediterranean deep-water rose shrimp (Parapenaeus longirostris (Lucas, 1846), Crustacea, Decapoda) from the Alicante Gulf (s.e. Spain).

The deep-water rose shrimp (Parapenaeus longirostris) is a demersal species and an important resource for the trawl fishery in the Alicante Gulf (S.E. Spain). This paper describes, for first time in this area, certain biometric relationships, as well as growth parameters and reproductive patterns of the species. The results showed a sexual size dimorphism, with a negative allometry of relative growth and high rates of absolute growth, both particularly in males. However, females dominated in the catch proportion. The spawning period occurred throughout the year, but especially in June-July and in October-November and the maturation stage for females takes place within the second year of life

Spatially Explicit Modeling Reveals Cephalopod Distributions Match Contrasting Trophic Pathways in the Western Mediterranean Sea

Populations of the same species can experience different responses to the environment throughout their distributional range as a result of spatial and temporal heterogeneity in habitat conditions. This highlights the importance of understanding the processes governing species distribution at local scales. However, research on species distribution often averages environmental covariates across large geographic areas, missing variability in population- environment interactions within geographically distinct regions. We used spatially explicit models to identify interactions between species and environmental, including chlorophyll a (Chla) and sea surface temperature (SST), and trophic (prey density) conditions, along with processes governing the distribution of two cephalopods with contrasting life-histories (octopus and squid) across the western Mediterranean Sea. This approach is relevant for cephalopods, since their population dynamics are especially sensitive to variations in habitat conditions and rarely stable in abundance and location. The regional distributions of the two cephalopod species matched two different trophic pathways present in the western Mediterranean Sea, associated with the Gulf of Lion upwelling and the Ebro river discharges respectively. The effects of the studied environmental and trophic conditions were spatially variant in both species, with usually stronger effects along their distributional boundaries. We identify areas where prey availability limited the abundance of cephalopod populations as well as contrasting effects of temperature in the warmest regions. Despite distributional patterns matching productive areas, a general negative effect of Chla on cephalopod densities suggests that competition pressure is common in the study area. Additionally, results highlight the importance of trophic interactions, beyond other common environmental factors, in shaping the distribution of cephalopod populations. Our study presents a valuable approach for understanding the spatially variant ecology of cephalopod populations, which is important for fisheries and ecosystem management.Versión del editor4,411

History of the Spanish demersal fishery in the Atlantic and Mediterranean Seas

Long fisheries time series allow the review of baselines and inform our knowledge of past events that have conditioned the recent history of the stocks. In this study, we investigated trends in fisheries landings data for the most representative Atlantic and Mediterranean demersal fisheries off the Spanish Iberian Peninsula and the Balearic Islands (1933–1986). The aim was to analyse the evolution of demersal species exploitation and detect changes in landings and fishing tactics. Ten species were selected, which included teleosts, crustaceans, and cephalopods. Results indicated a decrease in Landings Per Unit of Capacity (LPUC) in six of the species examined. While in the Atlantic the process of substitution or incorporation of new species to the fisheries occurs progressively, in the Mediterranean this incorporation occurs simultaneously for many of the species. Four main fishing tactics (landing pattern obtained from the classification analysis of landings per species) were identified. Geographically nearby and connected regions developed similar fishing tactics to each other, and also changed over time. While the fleets from isolated regions were more specialized, and only carrying out one fishing tactic during the study period. Improvements in LPUC with the implementation of new technology and legislative and management measures were not observed.Postprint2,27