scholarly journals Temporal variation of seston biomarkers within the Humboldt Current System off northern Chile (21

2012 ◽  
Vol 3 (1) ◽  
pp. 17
Author(s):  
Sergio Rossi ◽  
Enrique Isla ◽  
Susanne Fietz ◽  
Alfredo Martìnez-Garcia ◽  
Elisabet Sañé ◽  
...  

Proportions and concentrations of seston fatty acids, n-alkanes and glycerol dialkyl glycerol tetraethers (GDGTs) were used to assess potential differences in the phytoplankton composition and food quality in the Humboldt Current System (winter 2006, summer 2007 and winter 2007) in surface, oxycline, intermediate and bottom water layers. The zone below the intermediate depth was poorer in fatty acids (minimum 15 – maximum 117mg fatty acids L

Author(s):  
Carmen E. Morales ◽  
José L. Blanco ◽  
Mauricio Braun ◽  
Nelson Silva

Chlorophyll-a (chl-a) distribution and associated physical (temperature, salinity) and chemical (dissolved oxygen) conditions off northern Chile (Humboldt Current System), during the austral summer (February–March) and autumn (May) of 1994, were studied in the region bounded by ∼18–24°S and 70–72°W (out to ∼200 km from the coast; 0–100 m depth); within this region, nutrients were measured in an area of persistent coastal upwelling (∼19–22°S, out to 80 km from the coast). Temperature and salinity distributions, as well as nutrient concentrations, indicated the occurrence of active upwelling during both cruises. Also, and together with maps of geopotential anomaly (0/200 dbar) and depth of the thermocline (15°C isotherm), their distribution suggested the presence of a mainly equatorward flow, anticyclonic eddy-like structures, and intrusions of warm (>19°C), high salinity (>35·0 psu), subtropical water towards the coast. A tongue of cooler and lower salinity water, and of lower flow fields, extended from the coast towards the offshore zone during both sampling periods, in association with higher chl-a concentrations (>1 mg m−3, >20 mg m−2 between 0 and 25 m depth) and predominance of net-phytoplankton (>20 μm). The comparison of these results with those for the winter and spring of 1993 in the same area suggest a relatively weak seasonal signal in chl-a concentration during the 1993–1994 period, with higher water column concentrations during the summer and spring periods in the selected upwelling area, though surface chl-a concentrations for the whole of the area did not vary significantly.


2018 ◽  
Vol 53 ◽  
pp. 63 ◽  
Author(s):  
Lissette D. Paredes ◽  
Mauricio F. Landaeta ◽  
M. Teresa González

This paper presents an analysis of spatial and temporal patterns in the fish larvae composition of two geographically adjacent nearshore areas within the Humboldt Current System (HCS), northern Chile. Five surveys were performed at Isla Santa María (ISM) and Punta Coloso (COL), Mejillones Peninsula. Ichthyoplankton were collected every 15 days in 2014 during the austral autumn-winter (May to August). A total of 412,410 fish larvae belonging to 36 taxa were identified, a high abundance compared with other HCS regions. Data also revealed similarities in species recorded compared with central Chile as well as differences compared with central Peru; a number of families were shared between these HCS regions and other systems (e.g., Canarias Current System). ISM was dominated by intertidal-subtidal species (e.g., Helcogrammoides cunninghami), while Engraulis ringens was most abundant at COL. Several species were positively correlated with dissolved oxygen (e.g., Auchenionchus microcirrhis), as well as temperature and Ekman transport (e.g., Sebastes oculatus), while the presence of others is negatively related to the same environmental parameters (e.g., Graus nigra). Results suggest that larvae differently utilize these two areas as a refuge or for feeding, and that adults might be coupling their spawning periods with short-term oceanographic features. Larval fish assemblages of nearshore areas in northern Chile are described here for the first time and highlight the important role of these two areas in the early developmental stages of fish species.


PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253314
Author(s):  
Fabián Guzmán-Rivas ◽  
Marco Quispe-Machaca ◽  
Dante Queirolo ◽  
Mauricio Ahumada ◽  
Ángel Urzúa

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.


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