ICHTHYOPLANKTON IN INDEPENDENCIA BAY, PISCO, PERU:TEMPORAL AND SPATIAL RELATIONSHIPS


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jvelez [ at ] awi-bremerhaven.de

Abstract

Larval fish assemblages in Independencia Bay on the coast of Peru were examined using a combination of univariate and multivariate techniques. The plankton of Independencia Bay was sampled monthly during 2000, to ascertain ichthyoplankton composition, abundance, and seasonality, to determine diel abundance patterns and to assess the vertical variations of the dominant families in the area during a 24-hour cycle and relate those variations to oceanographic parameters. These data were used to assess the inferred function of the bay as spawning and nursery grounds and were related to the regional oceanography. Morphological development of some groups of the Ichthyoplankton from the bay is described. In total, 16,156 fish larvae, representing 34 families, 48 genera and 48 species were collected. Engraulidae, Normanichthyidae, Blenniidae, Gobiesoscidae, Haemulidae, Labrisomidae, Pinguipedidae and Atherinidae numerically dominated the larval fish fauna and comprised 96.8% of the larvae captured; the remaining 3.2% included several families. The monthly mean density of total fish larvae showed two peaks: one in spring, dominated by newly hatched mote sculpins (Normanichthyidae) and newly hatched and pre-flexion anchovies (Engraulidae). A second smaller peak in summer was dominated by preflexion-stage anchovies, followed by mote sculpins. Greatest mean larval fish densities were recorded between September and November, suggesting a major spawning period. The greatest mean density (no./100m3) during the spring peak was 7,492 larvae/100m3 recorded in October. The greatest mean density during summer was recorded in February (2,493 larvae/100m3). The occurrence of high larval fish densities and the wide range of larval stages suggest that Independencia Bay is a regionally important spawning and nursery ground for marine fish. The Principal Component Analysis (PCA) showed that temperature and salinity accounted for the largest fraction (74.4%) of the variability in the observed larval fish assemblage patterns. Vertical distribution patterns of ichthyoplankton were examined from two depths at two stations. Six families numerically dominated the diverse larval fish fauna, and comprised 97.6% of the larvae captured. The highest larval density and abundance cumulated through the water column was found at Panteón. The number of taxa was the same (5) at the surface at both stations, and was higher in m-water at Tunga (26) than at Panteón (21). Two patterns of larval vertical distribution were observed. There were no statistically significant differences between night and day densities of fish larvae at either depth. Nevertheless, a small degree of vertical redistribution was apparent.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
29th Annual Larval Fish Conference. Barcelona, SpainJuly..
Eprint ID
14648
Cite as
Velez, J. and Arntz, W. (2005): ICHTHYOPLANKTON IN INDEPENDENCIA BAY, PISCO, PERU:TEMPORAL AND SPATIAL RELATIONSHIPS , 29th Annual Larval Fish Conference. Barcelona, SpainJuly. .


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