scholarly journals Larval fish assemblages in two nearshore areas of the Humboldt Current System during autumn-winter in northern Chile

2018 ◽  
Vol 53 ◽  
pp. 63 ◽  
Author(s):  
Lissette D. Paredes ◽  
Mauricio F. Landaeta ◽  
M. Teresa González
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Fish Larvae ◽  
Current System ◽  
Ekman Transport ◽  
Northern Chile ◽  
Spatial And Temporal Patterns ◽  
Humboldt Current ◽  
Engraulis Ringens ◽  
Humboldt Current System

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.

scholarly journals Modelling seasonal patterns of larval fish parasitism in two northern nearshore areas in the Humboldt Current System

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lissette D. Paredes ◽  
Mauricio F. Landaeta ◽  
Carlos Molinet ◽  
M. Teresa González
Keyword(s):  
Fish Species ◽  
Seasonal Variations ◽  
Larval Fish ◽  
Fish Larvae ◽  
Current System ◽  
Gamma Model ◽  
Austral Spring ◽  
Humboldt Current ◽  
Humboldt Current System ◽  
Reproductive Processes

AbstractMacro- and micro-environmental factors modulate parasite loads in fish, determining parasitic abundances, diversity, and interaction dynamics. In this study, seasonal variations in larval ectoparasites on fish larvae in the northern Humboldt Current System (HCS) were evaluated using a delta-gamma generalized linear model to predict their occurrence frequencies. Fish larvae were collected from two nearshore areas during austral spring–summer and autumn–winter. Only five (of 38) larval fish species were parasitized by copepods: Gobiesox marmoratus, Ophiogobius jenynsi, Helcogrammoides cunninghami, Myxodes sp., and Auchenionchus crinitus. A binomial model showed that the presence/absence of parasitized fish larvae varied among the fish species and their larval abundances, while a positive delta-gamma model showed that ectoparasite frequency varied among the seasons and fish species. Seasonal variations in parasitized fish larvae frequency could be associated with host and parasite reproductive processes, which are related to oceanographic features responsible for larval retention and subsequent higher infestation probabilities. Host length was positively correlated with ectoparasite length, suggesting early infection and combined growth until the detachment of the ectoparasite. Our results suggest that infestation patterns in larval fish species can be identified using delta-gamma models and that they respond to local (retention) and high-scale (HCS) processes.

Chlorophyll-a distribution and mesoscale physical processes in upwelling and adjacent oceanic zones off northern Chile (summer–autumn 1994)

2001 ◽  
Vol 81 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Carmen E. Morales ◽  
José L. Blanco ◽  
Mauricio Braun ◽  
Nelson Silva
Keyword(s):  
Coastal Upwelling ◽  
Current System ◽  
Austral Summer ◽  
Nutrient Concentrations ◽  
Northern Chile ◽  
Humboldt Current ◽  
Oxygen Conditions ◽  
Salinity Water ◽  
Humboldt Current System ◽  
Seasonal Signal

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.

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 ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Food Quality ◽  
Bottom Water ◽  
Current System ◽  
Northern Chile ◽  
Phytoplankton Composition ◽  
Humboldt Current ◽  
Intermediate Depth ◽  
Water Layers ◽  
Humboldt Current System

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

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