scholarly journals Stable isotope and fatty acid analyses reveal significant differences in trophic niches of smooth hammerhead Sphyrna zygaena (Carcharhiniformes) among three nursery areas in northern Humboldt Current System

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11283
Author(s):  
Eduardo Segura-Cobeña ◽  
Joanna Alfaro-Shigueto ◽  
Jeffrey Mangel ◽  
Angel Urzua ◽  
Konrad Górski
Keyword(s):  
Fatty Acid ◽  
Current System ◽  
Nursery Area ◽  
San Jose ◽  
Humboldt Current ◽  
Nursery Areas ◽  
Peruvian Coast ◽  
Humboldt Current System ◽  
Management And Conservation ◽  
Trophic Niches

Fishery pressure on nursery areas of smooth hammerhead in northern Peruvian coast have become a serious threat to sustainability of this resource. Even though, some management actions focused on conservation of the smooth hammerhead populations were proposed in recent years, their scientific foundations are often limited, and biomass of smooth hammerhead in Peruvian waters continues to decrease. To inform management and conservation, this study aims to evaluate the trophic niche of smooth hammerhead juveniles from three nursery areas in the northern Peruvian coast using stable isotope and fatty acid analyses. First, we compared the environmental characteristics of each nursery area (i.e., sea surface temperature and chlorophyll-a concentration) and concluded that nursery areas differed significantly and consistently in sea surface temperature. Subsequently, we evaluated isotopic composition of carbon and nitrogen and fatty acid profiles of muscle and liver tissues collected from juvenile smooth hammerhead from each nursery area. We found that juvenile smooth hammerhead captured in San José were enriched in heavier 13C and 15N isotopes compared to those captured in Máncora and Salaverry. Furthermore, the broadest isotopic niches were observed in juveniles from Máncora, whereas isotopic niches of juveniles from Salaverry and San José were narrower. This difference is primarily driven by the Humboldt Current System and associated upwelling of cold and nutrient rich water that drives increased primary production in San José and, to a less extent, in Salaverry. Compared to smooth hammerhead juveniles from Máncora, those from San José and Salaverry were characterised by higher essential fatty acid concentrations related to pelagic and migratory prey. We conclude that smooth hammerhead juveniles from three nursery areas in the northern Peruvian coast differ significantly in their trophic niches. Thus, management and conservation efforts should consider each nursery area as a unique juvenile stock associated with a unique ecosystem and recognize the dependence of smooth hammerhead recruitment in San José and Salaverry on the productivity driven by the Humboldt Current System.

scholarly journals Genetic analysis reveals historical and contemporary population dynamics in the longfin squid Doryteuthis gahi: implications for cephalopod management and conservation

2019 ◽  
Vol 76 (4) ◽  
pp. 1019-1027 ◽  
Author(s):  
Niall J McKeown ◽  
Alexander I Arkhipkin ◽  
Paul W Shaw
Keyword(s):  
Current System ◽  
Glacial Refugia ◽  
Current Management ◽  
Humboldt Current ◽  
Phenotypic Differences ◽  
Abrupt Changes ◽  
Humboldt Current System ◽  
Adult Dispersal ◽  
Plastic Responses ◽  
Management And Conservation

Abstract Population genetic structure of the Patagonian longfin squid Doryteuthis gahi was assessed across the Falkland Islands, central-southern Chile, and Peru. Microsatellite and mtDNA data partitioned samples into two groups: one consisting of the Peruvian samples, the other comprised the Chilean and Falklands samples, with no sub-structuring within either group. Recurrent demographic independence between groups can be linked to abrupt changes in continental shelf features between the Peruvian and central Chilean sites restricting adult dispersal. Phylogeographic analyses indicate a prolonged period of isolation between the Peruvian and Chilean–Falkland groups which may include divergence in allopatric glacial refugia. Both groups have experienced dissimilar historical population size dynamics with the Peruvian population exhibiting signals of size fluctuations, similar to other species in the area, that align with postglacial changes in the productivity of the Humboldt Current system. Genetic cohesion among central-southern Chilean and Falklands samples supports connectivity across current management boundaries and indicates that phenotypic differences between D. gahi from these areas reflect plastic responses to environmental heterogeneity. The study adds to evidence that loliginid squids typically display connected populations over large geographical areas unless specific oceanographic features restrict gene flow. Recognition of the Peruvian and Chilean–Falklands groups as distinct evolutionary significant units is recommended.

scholarly journals Latitudinal changes in the lipid content and fatty acid profiles of juvenile female red squat lobsters (Pleuroncodes monodon) in breeding areas of the Humboldt Current System

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253314
Author(s):  
Fabián Guzmán-Rivas ◽  
Marco Quispe-Machaca ◽  
Dante Queirolo ◽  
Mauricio Ahumada ◽  
Ángel Urzúa
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Lipid Content ◽  
Current System ◽  
Fishing Industry ◽  
Fatty Acid Profiles ◽  
Humboldt Current ◽  
Juvenile Female ◽  
Humboldt Current System ◽  
Squat Lobsters

The red squat lobster Pleuroncodes monodon is a species of high commercial value that inhabits the Humboldt Current System. Along the Chilean coast, two populations are exploited by the fishing industry, one located off the coast of Coquimbo and the other off the coast of Concepción. Yet, it is unknown whether there are differences in the “bioenergetic fuel” (measured as lipid content and fatty acid profile) of juvenile populations of these two fishing units and whether these bioenergetic compounds can be modulated by differences in the environmental parameters (such as temperature or chlorophyll-a) of their breeding areas. To shed some light on this, we measured the lipid content and fatty acid profiles of the viscera and muscle of juvenile female red squat lobsters from these two fishing units, specifically from breeding areas near long-exploited fishing grounds: a) the northern fishing unit (NFU, from 26°S to 30°S) and b) the southern fishing unit (SFU, from 32°S to 37°S). We found differences in the lipid content, fatty acid profiles, and ratios of saturated fatty acids (C16:0/C18:0) of juvenile females from these two locations. In addition, the essential fatty acids (DHA/EPA) found in the viscera versus the muscle of these lobsters varied significantly. Juvenile females from the SFU (i.e. Concepción) showed a higher lipid content compared to the juvenile females from the NFU (i.e. Coquimbo). Consistently, individuals from the SFU had a higher content of fatty acids, which also proved to be richer in saturated and monounsaturated fatty acids compared to those from the NFU. Our results are important for the fisheries in both areas because these juvenile populations are the source of new recruits for the adult populations that are exploited by the fishing industry. Our study also aids in determining which populations are healthier or of better quality in bioenergetic terms. Furthermore, increasing the incorporation of bioenergetic parameters in fishery models is essential for the recruitment and stock assessment within an ecosystem approach, since it allows for the evaluation of the nutritional condition of different fishing populations.

Climate change scenarios experiments predict a future reduction in small pelagic fish recruitment in the Humboldt Current system

2013 ◽  
Vol 19 (6) ◽  
pp. 1841-1853 ◽  
Author(s):  
Timothée Brochier ◽  
Vincent Echevin ◽  
Jorge Tam ◽  
Alexis Chaigneau ◽  
Katerina Goubanova ◽  
...  
Keyword(s):  
Climate Change ◽  
Current System ◽  
Pelagic Fish ◽  
Climate Change Scenarios ◽  
Small Pelagic Fish ◽  
Humboldt Current ◽  
Fish Recruitment ◽  
Humboldt Current System

scholarly journals Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

2012 ◽  
Vol 9 (3) ◽  
pp. 1183-1194 ◽  
Author(s):  
E. Mayol ◽  
S. Ruiz-Halpern ◽  
C. M. Duarte ◽  
J. C. Castilla ◽  
J. L. Pelegrí
Keyword(s):  
Current System ◽  
Negative Relationship ◽  
Water Layer ◽  
Humboldt Current ◽  
Marine Life ◽  
Small Water ◽  
System A ◽  
Subsurface Waters ◽  
Humboldt Current System ◽  
Upper Mixed Layer

Abstract. Carbon dioxide and coupled CO2 and O2-driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log10 pO2pCO2) and the pH-dependent aragonite saturation (Ω) to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100 m to about 300 m depth and supporting elevated pCO2 values. The lowest RI values, associated to aerobic stress, were found at about 200 m depth and decreased towards the Equator. Increased pCO2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42° S and 28° S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO2–driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO2-driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000 m depth. Overall pCO2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

The Humboldt Current System of Northern and Central Chile

2007 ◽  
pp. 195-344 ◽  
Author(s):  
Martin Thiel ◽  
Erasmo Macaya ◽  
Enzo Acu√±a ◽  
Wolf Arntz ◽  
Horacio Bastias ◽  
...  
Keyword(s):  
Current System ◽  
Humboldt Current ◽  
Central Chile ◽  
Humboldt Current System

scholarly journals Marine heatwaves in the Humboldt current system: from 5-day localized warming to year-long El Niños

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alice Pietri ◽  
François Colas ◽  
Rodrigo Mogollon ◽  
Jorge Tam ◽  
Dimitri Gutierrez
Keyword(s):  
Hot Spot ◽  
Current System ◽  
World Ocean ◽  
Temperature Data ◽  
Sea Surface ◽  
Thermal Impact ◽  
Humboldt Current ◽  
Coastal System ◽  
Long Duration ◽  
Humboldt Current System

AbstractDuring the last 4 decades punctual occurrences of extreme ocean temperatures, known as marine heatwaves (MHWs), have been regularly disrupting the coastal ecosystem of the Peru-Chile eastern boundary upwelling system. In fact, this coastal system and biodiversity hot-spot is regularly impacted by El Niño events, whose variability has been related to the longest and most intense MHWs in the world ocean. However the intensively studied El Niños tend to overshadow the MHWs of shorter duration that are significantly more common in the region. Using sea surface temperature data from 1982 to 2019 we investigate the characteristics and evolution of MHWs, distinguishing events by duration. Results show that long duration MHWs (> 100 days) preferentially affect the coastal domain north of 15° S and have decreased in both occurrence and intensity in the last four decades. On the other hand, shorter events, which represent more than 90% of all the observed MHWs, are more common south of 15° S and show an increase in their thermal impact as well as on the number of affected days, particularly those spanning 30–100 days. We also show that long duration MHWs variability in the coastal domain is well correlated with the remote equatorial variability while the onset of short events (< 10 days) generally goes along with a relaxation of the local coastal wind.

Breeding abundance and population trend of the Peruvian Diving-petrel Pelecanoides garnotii in Chile: Recovery of an endangered seabird?

2019 ◽  
Vol 30 (3) ◽  
pp. 423-433
Author(s):  
CLAUDIA E. FERNÁNDEZ ◽  
MATÍAS PORTFLITT-TORO ◽  
DIEGO MIRANDA-URBINA ◽  
PAULA PLAZA ◽  
NICOLAS LUNA ◽  
...  
Keyword(s):  
Current System ◽  
Legal Protection ◽  
Breeding Population ◽  
Management Plan ◽  
Population Trend ◽  
Humboldt Current ◽  
Breeding Habitats ◽  
Large Populations ◽  
Humboldt Current System ◽  
Diving Petrel

SummaryAs island ecosystems are among the most critical breeding habitats for seabirds, their protection should enhance population viability for many species. The Peruvian Diving-petrel Pelecanoides garnotii breeds only in Chile and Perú, is an endangered seabird with historically large populations of over 100,000 breeding pairs, but fewer than 1,000 remained in the 1980s and it became the first endangered seabird of the Humboldt Current System. In Chile, they breed on five islands, three of which are legally protected, but only two have a management plan. Between 2010 and 2014, we evaluated the density of nests, burrow occupancy, and colony patch sizes on the islands to estimate the breeding population. The population trend was assessed by compiling historical data available in the literature and several unpublished technical reports. The current breeding population size in Chile was ∼12,500 breeding pairs (95% CI: 10,613–14,676 pairs) that is ∼34% of the breeding pairs reported for Peru (∼36,450 pairs). Choros Island, the only island with adequate protection, accounted for ∼95% of the total breeding population of the Peruvian Diving-petrel in Chile. Historical population trends showed a significant increase in breeding pairs during recent years on Choros Island. It seems that the adequate legal protection of Choros Island is leading to the recovery of Peruvian Diving-petrels, demonstrating that protection of breeding colonies remains an essential strategy for the conservation of endemic seabirds.

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