ARISTEUS ANTENNATUS PDF

Abstract Aristeus antennatus is an ecologically and economically important deep-water species in the Mediterranean Sea. In this study we investigated the genetic variability of A. By comparing our new samples with available data from the Western area, we aim to identify potential genetic stocks of A. We found two main results: i the genetic diversity values consistent with previous data within the Mediterranean and the absence of barriers to gene flow within the Mediterranean Sea; ii a constant long-term effective population size in almost all demes but a strong signature of population expansion in the pooled sample about 50, years B.

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Licence This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. Morphological identification and molecular confirmation of the deep-sea blue and red shrimp Aristeus antennatus larvae.

Abstract The early life stages of the blue and red shrimp Aristeus antennatus Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae were described by Heldt in based on plankton samples, larval rearing and assumptions of species habitat.

Even with adequate keys, identification of its first larval stages remained a difficult task due to the lack of specific morphological characters which would differentiate them from other Penaeoidea species. DNA from the larvae was extracted and the molecular markers Cytochrome Oxidase I and 16S rDNA were sequenced and compared to that of adults with the objective of confirming the previous morphological description.

Then, we present additional information to the morphological description of Aristeus antennatus larval stages through scanning electron microscopy and molecular analysis. This represents the first documented occurrence of Aristeus antennatus larvae off the Catalan coast and sets the grounds for further work on larval ecology and population connectivity of the species, which is an important contribution to a more sustainable fishery.

Introduction The deep-sea blue and red shrimp Aristeus antennatus Risso, ; Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae is one of the most valuable fishing resources in the Mediterranean Sea. As this fishery progresses toward more integrative methods of stock assessment and management, filling the knowledge gap about the early life stages of Aristeus antennatus is a crucial step in the study of its dispersal and population connectivity. In dendrobranchiate shrimps, the first larval stage hatching from the egg is usually a free-living nauplius.

This stage has up to six substages depending on the species. It is followed by a variable number of zoeal stages often referred to as protozoea early zoeae, with natatory antennules and antennae and mysis late zoeae, where the natatory function is assured by the pereiopods. The last mysis then metamorphoses into the first decapodid, which after a number of moults will come to settle in the adult habitat Anger, The description of the larval stages of Aristeus antennatus Heldt, was based on 35 individuals caught in a plankton survey around the Balearic archipelago.

This morphological identification has never been confirmed since. The morphological description of a second mysis stage Torres et al. This is not possible in the case of Aristeus antennatus due to the particularity of dendrobranchiate shrimps releasing their eggs directly to the water column, as opposed to being carried by females.

To our knowledge, only one deep-sea Penaeoid larva from a plankton survey has been molecularly identified Bracken-Grissom et al. The available descriptions of Penaeoid larvae from laboratory studies correspond only to species inhabiting shallow waters—as for instance the caramote prawn Penaeus kerathurus Torkmen, —since females are easily cultured in tanks and eggs can be collected from the water upon release. No study has yet reported the culture of females of any deep-sea Penaeoid species.

On this matter, the early larval stages of Aristeus antennatus are no exception. In fact, the description of the PZI was based on a single individual captured in the plankton of Balearic waters, in the Western Mediterranean Sea Heldt, However, the distinction between Aristeidae and Benthesicymidae PZI stage is more difficult because the only morphological character that allows their differentiation is a small endopod on the third maxilliped mxp3 , present in Aristeus antennatus and absent in Gennadas spp.

Heldt, ; Gurney, In the case of Aristeus antennatus, the mxp3 is birramous, with two long plumose setae and one small simple seta on the exopod. In the case of Gennadas spp. The reproductive period of the genus Gennadas has not yet been studied, but larvae caught in the plankton all year round have been classified as Gennadas spp.

The reproductive period of Aristeus antennatus in the Mediterranean Sea is strictly seasonal in the summer Company et al. With both larval types occurring concurrently during the summer, their morphological differentiation becomes a key issue in the study of decapod larval communities and of Aristeus antennatus larval distribution in particular. The available descriptions of penaeoid larvae from plankton surveys have generally based their identification on an extensive knowledge of the adult morphology and ecology Heldt, , ; Gurney, The objective of this study was to examine the morphology of the first protozoea of the deep-sea blue and red shrimp Aristeus antennatus in order to find useful characters to distinguish it from Gennadas spp.

Materials and Methods Sampling and morphological identification of Aristeus antennatus and Gennadas spp. Nevertheless, the presence of Gennadas spp.

Plankton samples were taken using a 0. Samples were sorted in the laboratory using a Leica Wild M6 stereomicroscope and all larvae morphologically identified as Aristeus antennatus following the available descriptions Heldt, ; Torres et al.

Figure 1: Stations where larvae were selected. Red dots: summer sampling. Blue dots: winter sampling. Bathymetry is shown every m. DOI: They were sorted on board using an Olympus SZ stereomicroscope and larvae morphologically identified as Gennadas spp. Identifications of larvae through DNA barcoding are only reliable when the obtained sequences are compared to those of adult specimens of known species.

They had been collected, preserved and their DNA amplified and the resulting sequences were therefore available for comparison. In the case of Gennadas elegans, two adult individuals were selected from a sampling cruise in May in the Mediterranean Sea.

They had been previously identified by Dr. For the purpose of this paper, we extracted DNA from their abdominal tissue and sequenced the product following the same method as for Gennadas spp. Analysis of the protozoea I pool Morphological analysis In order to closely examine the morphology of the PZI larvae from the summer sampling, scanning electron microscopy SEM was used for 10 randomly selected individuals identified as Aristeus antennatus PZI. Also, three individuals from the winter sampling, morphologically identified as Gennadas spp.

PZI, were randomly selected. Furthermore, measurements of carapace length, telson rami length, telson angle and length of last somite of pleon were taken for all remaining individuals from the winter sampling identified as Gennadas spp. Also, the same measurements were carried out for 10 individuals from the summer sampling, identified as Aristeus antennatus. Molecular analysis In order to confirm the identity of a representative sample of the PZI pool found in the summer sampling, we randomly selected 24 PZI individuals attributed to Aristeus antennatus, from a total of found.

Selection was done according to spatial criteria with the objective of covering the whole study area. A maximum of three larvae per station were selected where the total number found was highest.

We also randomly selected four PZI larvae from the winter sampling, morphologically attributed to Gennadas spp. Information about larvae analyzed and their GenBank accession numbers are shown in Table 1.

Table 1: List of protozoea I larvae analyzed by station.

CISCO NETWORKERS 2012 PDF

Aristeidae

Licence This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. Morphological identification and molecular confirmation of the deep-sea blue and red shrimp Aristeus antennatus larvae. Abstract The early life stages of the blue and red shrimp Aristeus antennatus Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae were described by Heldt in based on plankton samples, larval rearing and assumptions of species habitat. Even with adequate keys, identification of its first larval stages remained a difficult task due to the lack of specific morphological characters which would differentiate them from other Penaeoidea species. DNA from the larvae was extracted and the molecular markers Cytochrome Oxidase I and 16S rDNA were sequenced and compared to that of adults with the objective of confirming the previous morphological description. Then, we present additional information to the morphological description of Aristeus antennatus larval stages through scanning electron microscopy and molecular analysis.

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