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In this study, the four most important species in the Humboldt Current System (HCS), Engraulis ringens, Sardinops sagax, Trachurus murphyi, and Dosidicus gigas were linked to four climate indices, sea surface temperature (SST) and wind speed (WS) based on multivariate statistical analyses, aiming to explore their nonstationary responses to climate variability. Significant decadal variations in the catches were identified, with regime shifts in the mid-1970s, early 1990s, and late 1990s. These shifts corresponded well to climatic and environment regime shifts during these periods. However, the response patterns to climate and environmental variations varied among species. Compared with other physical drivers, seawater temperature, wind speed, the Pacific Decadal Oscillation (PDO), and the North Pacific Gyre Oscillation (NPGO) had greater ecological importance in driving changes in the four pelagic species. The variations in the important climate events influenced seawater temperature and wind speed fluctuations within the HCS, impacting on these commercially important pelagic species. Furthermore, non-stationarity was identified in the relationships between climate/environment and species catches, with different species showing different threshold years. The non-stationarity may be attributed to the transitions between warm and cold periods within the HCS, as well as shifts between strong and weak phases of pressure system. This study helps further understand changes in the HCS caused by fluctuations in climate and environment. [ABSTRACT FROM AUTHOR]

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE. [ABSTRACT FROM AUTHOR]

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE.

The hyperarid Atacama Desert coast receives scarce moisture inputs mainly from the Pacific Ocean in the form of marine advective fog. The collected moisture supports highly specialized ecosystems, where the bromeliad Tillandsia landbeckii is the dominant species. The fog and low clouds (FLCs) on which these ecosystems depend are affected in their interannual variability and spatial distribution by global phenomena, such as ENSO. Yet, there is a lack of understanding of how ENSO influences recent FLCs spatial changes and their interconnections and how these variations can affect existing Tillandsia stands. In this study, we analyze FLCs occurrence, its trends and the influence of ENSO on the interannual variations of FLCs presence by processing GOES satellite images (1995–2017). Our results show that ENSO exerts a significant influence over FLCs interannual variability in the Atacama at ~ 20°S. Linear regression analyses reveal a relation between ENSO3.4 anomalies and FLCs with opposite seasonal effects depending on the ENSO phase. During summer (winter), the ENSO warm phase is associated with an increase (decrease) of the FLCs occurrence, whereas the opposite occurs during ENSO cool phases. In addition, the ONI Index explains up to ~ 50 and ~ 60% variance of the interannual FLCs presence in the T. landbeckii site during summer and winter, respectively. Finally, weak negative (positive) trends of FLCs presence are observed above (below) 1000 m a. s. l. These results have direct implications for understanding the present and past distribution of Tillandsia ecosystems under the extreme conditions characterizing our study area. [ABSTRACT FROM AUTHOR]

Abstract The Eastern Pacific leatherback turtle population (Dermochelys coriacea) has declined precipitously in recent years. One of the major causes is bycatch from coastal and pelagic fisheries. Fisheries observations are often underutilized, despite strong potential for this data to affect policy. In this study, we created a spatiotemporal species distribution model that synthesizes fisheries observations with remotely sensed environmental data. The model will be developed into a dynamic management tool for the Eastern Pacific leatherback population. We obtained leatherback observation data from multiple fisheries that have operated in the Southeast Pacific (2001–2018). A dynamic Poisson point process model was applied to predict leatherback intensity (observation per unit area) as a function of dynamic environmental covariates. This model serves as a tool for application by managers and stakeholders toward the reduction of leatherback turtle bycatch and provides a modeling framework for analyzing fisheries observations from other vulnerable populations and species.

The Eastern Pacific leatherback turtle population (Dermochelys coriacea) has declined precipitously in recent years. One of the major causes is bycatch from coastal and pelagic fisheries. Fisheries observations are often underutilized, despite strong potential for this data to affect policy. In this study, we created a spatiotemporal species distribution model that synthesizes fisheries observations with remotely sensed environmental data. The model will be developed into a dynamic management tool for the Eastern Pacific leatherback population. We obtained leatherback observation data from multiple fisheries that have operated in the Southeast Pacific (2001–2018). A dynamic Poisson point process model was applied to predict leatherback intensity (observation per unit area) as a function of dynamic environmental covariates. This model serves as a tool for application by managers and stakeholders toward the reduction of leatherback turtle bycatch and provides a modeling framework for analyzing fisheries observations from other vulnerable populations and species. [ABSTRACT FROM AUTHOR]

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The pelagic cephalopod species jumbo flying squid Dosidicus gigas is ecologically and economically important in the Humboldt ecosystem off Peru. This squid species is sensitive to oceanic environmental changes, and regional oceanographical variability is one of the important factors driving its redistribution. Off Peruvian waters, mesoscale eddies are ubiquitous and dominate the biogeochemical processes in this region. This study first explored the role of mesoscale eddies in regulating the environments and their effects on the abundance and habitat distribution of D. gigas off Peru by analyzing squid distribution in eddy-centric coordinates and building a habitat suitability index (HSI) model. Results indicated that the abundance and habitat distribution of D. gigas in mesoscale eddies varied across months, with significant differences observed between anticyclonic eddies (AE) and cyclonic eddies (CE). In AE, a higher abundance and proportion of suitable habitat occurred. While in CE, the abundance was relatively low and the suitable habitat was relatively less, concentrating at the periphery of CE. Based on the HSI model results, sea surface temperature (SST) and 50 m water temperature (T50m) in AE were more favorable for D. gigas , which was 0.3–0.5 °C lower than that in CE, yielding high-quality habitats and higher abundance of D. gigas. Our findings emphasized that mesoscale eddies have a significant impact on water temperature conditions and nutrient concentrations off Peruvian waters. • The eddy-induced changes in Dosidicus gigas distribution were first explored. • Mesoscale eddies have impacts on water temperature and nutrient condition. • A higher abundance of D. gigas and enlarged suitable habitat occurred in anticyclonic eddies. [ABSTRACT FROM AUTHOR]

Abstract Habitat modeling approach is a useful tool to detect potential habitat of pelagic fish species for better fishery exploitation and management. In this study, an integrated habitat modeling approach was applied to examine seasonal habitat patterns of an ecologically and economically important squid species Dosidicus gigas in the Southeast Pacific Ocean off Peruvian waters. Fisheries data of D. gigas and three crucial remotely-sensed environmental variables including sea surface temperature (SST), net primary production (NPP) and sea surface height anomaly (SSHA) during 2006–2015 were used to develop and validate the habitat model. Results revealed that the model output robust predictions of seasonal habitat suitability for D. gigas stock. Potential habitat exhibited strong seasonal variability, characterized by an expansion of suitable habitat during spring-autumn period and an extreme reduction in winter. These seasonal habitat patterns of D. gigas were largely driven by spatial distribution of favorable environmental conditions. Spatial correlation analysis indicated that the habitat quality of D. gigas was negatively correlated with SST in the areas between 8°–15°S and 87°–79°W and with SSHA on the whole fishing ground. However, a negative relationship was found between HSI values and NPP in the east of 84°W, but with a significantly positive correlation in the west of 84°W. In addition, seasonal variations of CPUEs and latitude distribution of fishing efforts were highly coincided with the variability trends in the area of suitable habitats and their latitudinal distributions. Interannual variability was shown in the averaged HSI of D. gigas. Furthermore, comparing to the strong El Niño year in 2015, the La Niña event in 2011 yielded more enlarged favorable regions of each environmental factor in each season, leading to form extremely high-quality habitats. Highlights • A habitat model was built to examine seasonal habitats of jumbo squid off Peru. • Potential habitats of jumbo squid showed significant seasonal spatial patterns. • Environmental conditions strongly affected seasonal habitats of jumbo squid. [ABSTRACT FROM AUTHOR]

The gut contents of 292 planktivorous fish, from four families (Atherinopsidae, Clupeidae, Engraulidae and Scombridae) and seven species, captured along the coast of the southeast Pacific, were examined for microplastic contamination. Only a small fraction of all studied fish (2.1%; 6 individuals) contained microplastic particles in their digestive tract. Microplastics found were degraded hard fragments and threads, ranging from 1.1 to 4.9 (3.8 ± SD 2.4) mm in length, and of various colours, which suggests that the planktivorous fish species examined herein did not capture microplastics on the basis of their colour. The low prevalence of microplastic contamination in planktivorous fishes found in this study suggests that the risk of accidental ingestion by these species might be limited in the coastal upwelled waters of the southeast Pacific, perhaps due to small human population and highly dynamic oceanographic processes. [ABSTRACT FROM AUTHOR]

The jumbo flying squid Dosidicus gigas is a highly migratory species distributed throughout the Eastern Pacific Ocean. An integrated habitat suitability index (HSI) model was developed to evaluate the effects of climate variability (i.e. El Niño-Southern Oscillation) on the habitat suitability for D. gigas in the Southeast Pacific Ocean off Peru. The data used in the analysis included catch and fishing effort from the Chinese squid-jigging fishery over 2006-2013, as well as remotely sensed environmental data including sea surface temperature, chlorophyll a and sea surface height anomaly. Arithmetic mean HSI model was shown to have a better predictive performance and used to predict the HSI values and identify the suitable habitat for D. gigas over 2006-2012. Fishery and environmental data in 2013 was used to validate the model. The latitudinal location of suitable habitat was found to be important in determining the distribution of fishing efforts. Cross-correlation plot exhibited a significantly negative relationship between the average HSI values on the fishing ground and the Niño 3.4 indices with time-lags from 21 to 3 months, implying that the squid habitat responded quickly to the climate variability. Both suitable habitat areas and catches of D. gigas increased in La Niña periods and decreased in El Niño periods. The La Niña conditions tended to strengthen upwelling coupled with cool and nutrient-enhanced waters, which yielded favourable habitat conditions and high catches; whereas the El Niño conditions weakened upwelling coupled with warm and nutrient-depleted waters, which were unfavourable for squid habitat and reduced catches. Our findings indicated that large-scale climate variabilities could have great effects on squid habitat and such variabilities could be quantified by climate indices such as Oceanic Niño index. [ABSTRACT FROM AUTHOR]

Chilean marine habitats have supported sea turtle species since prehistorical times. Although information exists regarding their contemporary distribution and ecological role in the region, it is diffuse. This study aims to bring such data together and provide an up-to-date review of the ecology and conservation status of sea turtles in Chile. Detailed available data largely reflect interactions between Dermochelys coriacea and Caretta caretta with oceanic fisheries. Newspaper and local studies have reported the regular presence of Chelonia mydas and Lepidochelys olivacea in certain locations in northern Chile during the past decade. The latter species were particularly abundant in the area around a thermal discharge from a water-cooled power plant (Mejillones Bay, 23°S) in the Antofagasta Region, and accounts included several reports of negative interactions between these species and sea lions ( Otaria flavescens). Sea turtles found in Chilean waters are probably juveniles or subadults. No estimates have been made regarding the potential of the Chilean waters as feeding grounds or the relative importance of putative food items for sea turtles. Sea turtles are clearly present in Chilean waters, but we know little about factors that drive variation in their abundance. As such, there is a need for further exploration of the ecology of sea turtles in this region. [ABSTRACT FROM AUTHOR]

The liver coccidian Goussia cruciata is considered as a specific parasite of the genus Trachurus, but to date, this parasite has only been reported for Atlantic species ( Trachurus picturatus, Trachurus lathami, Trachurus trachurus and Trachurus mediterraneus). Therefore, this is the first report of this parasite in a species of Trachurus from the South Pacific. The prevalence and abundance of this coccidian in jack mackerel, T. murphyi, was determined, and its relationships with host variables such as total body length, condition factor and hepatosomatic index were evaluated. A total of 49 individuals were sampled from a commercial vessel of the central Chilean coast (36° 41′ S, 73° 06′ W) in November 2013 and February and May 2014. The parasite was identified by means of liver smears using light microscopy. The relationship between the abundance of the parasites and the host total length, condition factor and hepatosomatic index was analysed with Spearman's correlations. The sporogonic stages exhibited sporocysts that were morphologically concordant with coccidian G. cruciata. All hosts were parasitised with this coccidian, and the abundance varied between 2 and 224 oocytes per host. The parasite abundance was negatively correlated with the host total length. Infection levels of G. cruciata in T. murphyi apparently do not produce negative effects on fish condition. [ABSTRACT FROM AUTHOR]

Based on the 2001-2007 Chilean jack mackerel (Trachurus murphyi) face data from Chinese vessels, as well as the spatioemporal factors and the environmental factors such as sea surface temperature (SST), chlorophyll concentration, and temperature gradient (TGR) in the South-east Pacific Ocean, this paper analyzed the resource variation of T. murphyi and its relationships with the spatiotemporal and environmental factor in the Ocean by using generalized additive model (GAM). The results showed that the rate of deviance explained about CPUE (catch per unit mainly concentrated in the 17th-41st weeks of the year, with the CPUE reached the highest in the 25th - 31st weeks. The fishing ground of T. murphyi in the Ocean was mainly located in the waters of 78° - 98° W and 30° -43.5° S. The suitable sea surface temperature was in the range of 12 °C-18 °C, and the optimum temperature was 14 °C-16 °C. The appropriate chlorophyll concentration range and temperature gradient were 0.90-0. 18 mg · ,m-3 and 0.3 °-1.9 °C, respectively. The result s of stepwise GAM showed that the relative importance of the seven variables affecting the CPUE of T. murphyi was in the order of : weeks of the year, year, sea surface temperature, longitude, latitude, chlorophyll concentration, and temperature gradient. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the effect of hook size and seasonality on the artisanal long-line fishery of southern hake, Merluccius australis, in Chile. The study reveals no significant effects in either catch size composition or in catch rates between hooks of different size. However, the existence of a significant seasonal effect was verified on the catch rates. The researchers recommend that fishermen use alternative fishing gear and management measures for the fishery. They also suggest assigning differential catch quotas considering the spatial-temporal distribution of the resource and its migratory processes.

Abstract: The jack mackerel population has a widespread oceanic spawning habitat off central Chile, extending more than one thousand nautical miles offshore. In this paper, the spatial structure of jack mackerel eggs density is analyzed on the basis of four surveys carried out in oceanic waters (32°S–39°S, 75°W–92°W), from 1998 to 2001. In each survey, a grid of plankton stations was sampled through vertical hauls with WP2 plankton nets by using several purse-seine fishing ships sampling simultaneously along the E–W transects. With the aim of finding the bulk of the egg distribution within the surveyed area, an exploratory analysis between jack mackerel egg densities, latitude, longitude, and sea surface temperature (SST) was carried out. The spatial structure of the egg distribution was studied using geostatistical techniques. The bulk of the jack mackerel spawning tends to occur offshore between 80°W and 92°W, is maximal at 35°S and associated to SST warmer than 15–16°C. All of the variograms showed clear spatial autocorrelations without anisotropy, with the range fluctuating between 125 and 252 nautical miles. The range of variograms suggests that the spawning of jack mackerel is a large scale process, probably reflected in the adult behavior of the spawning by favoring a high dispersion of eggs and/or associated with sea surface temperature characterizing the subtropical frontal zone (16–18°C) off central Chile. [Copyright &y& Elsevier]