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Study of trace metals (Hg, Cd, Pb, Cu, and Zn) in cysts and biomass of Artemia salina (Linnaeus, 1758) (Branchiopoda, Anostraca) from the salt work of Sfax (Tunisia)
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The salt work of Sfax (southern Tunisia) is a potential site for the exploitation and production of local Artemia. Significant quantities of Artemia (cysts and biomass) are harvested each year and are used in larval feeding.Since this salt work is surrounded by several sources of emissions and pollution, assessing the quality of the cysts and biomass of Artemia, is of great importance. To this end the determination of some toxic trace metals: mercury (Hg), cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) was performed. The analyses of these metals were carried out by atomic absorption spectrometry.The results obtained showed that the concentrations in both cysts and biomass are low compared to those recorded for other strains that have already been commercialized and are used in fish farming. Thus, Artemia from the salt work of Sfax could be used without chemical risks in the feeding of fish larvae.
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Morphological anomalies in estuarine shrimp larvae
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For several years, major exoskeletal anomalies in two species of European estuarine shrimp of the genus Palaemon have been observed. The phenomenon has been described for P. longirostris and P. macrodactylus in the Gironde estuary (France) and affects all stages of the species’ life cycles: from juvenile to adult and in both wild and laboratory-reared individuals. In the present follow-up study, the effects of these anomalies in larval stages of the two species were investigated. Regular sampling across most of the saline estuary confirmed that the post-larval stages of both species were affected. The morphological anomalies (MA) observed in the larvae were of the same type as those described for the adult stages, although more limited and primarily affecting the rostrum and cephalothorax. Larvae were reared from hatching to the post-larval stage, and the appearance of the aforementioned anomalies was observed as early as in Zoea I. This was the case even in larvae whose mothers did not exhibit anomalies. For both species, the most advanced stage was the one most affected. Also, in the rearing experiment, a greater proportion of the P. macrodactylus larvae was affected than those of P. longirostris. No significant effects of MA on size or growth rate were demonstrated for larvae of either species in this study. Nevertheless, it provides data on larval growth that were not previously available. Further rearing experiments should be considered in order to explore any demonstrable effects of these morphological anomalies.
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Seasonal shifts of meiofauna community structures on sandy beaches along the Chennai coast, India
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Meiofauna standing stocks and community structures were studied at five sandy beaches along the Chennai coast of the Bay of Bengal, at the SE coast of India from January 2000 to February 2001. Meiofauna densities ranged from 1341.14 ± 1205.76 ind. 10 cm-2 to 3.73 × 106 ± 4.1 × 105 ind. 10 cm-2. Mean abundance was highest during February 2000 (35 565.85 ± 12 463.03 ind. 10 cm-2) and lowest during March 2000 (11 465.85 ± 4250.26 ind. 10 cm-2). As for individual stations, the highest abundances were found at Neelangarai (67 058.31 ± 7153.43 ind. 10 cm-2) and lowest at Marina (52 517.69 ± 5373.63 ind. m-2), respectively. As for taxa, the mean of the highest and lowest meiofauna abundance was observed in Copepoda and Cladocera during different months (109 372.29 ± 10 906.42 ind. 10 cm-2 and 1341.14 ± 241.15 ind. 10 cm-2) and at different stations (30 6242.40 ± 3905.26 ind. 10 cm-2 and 3755.20 ± 88.90 ind. 10 cm-2), respectively. Cluster analysis and principal component analysis showed that the elements of the meiofauna were separated into three major groups according to their distribution and abundance. Correspondence analysis showed the importance of meiofauna abundance with different months and stations. Ecological indices varied with month, station, and with meiofauna group. Monthly changes in the nematode-copepod index showed that both Ernavoor and Thiruvotriyur were more subjected to pollution, with the highest diversity and evenness values for nematodes among all stations.
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Estimation of the Individual Growth Parameters of the Brown Crab Callinectes Bellicosus (Brachyura, Portunidae) Using a Multi-Model Approach
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This study describes the growth parameters of Callinectes bellicosus based on samples from a coastal lagoon in the southern Gulf of California. A multi-model inference (MMI) approach is used for both sexes. The candidate models assessed were the Von Bertalanffy (VBGM), Gompertz, Logistic, and Schnute growth models. The criterion used to select the best models was the Akaike information criterion (AIC). The best models fitted were the Schnute model for males and the VBGM for females. The asymptotic carapace width (CW) in males, averaged according to the MMI principle, was 155.38 mm in males and 125.53 mm in females. This difference resulted from the females’ terminal moult to maturity. In females, no further growth occurs after this moult, whereas males continue to grow. The results of this study show that the use of an MMI approach is important because it can produce an improved description of the growth of crustaceans, such as Callinectes species, that exhibit this particular difference between the sexes.
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Presence of abdominal appendages in females of Caprella equilibra Say, 1818 (Peracarida, Amphipoda): is Metacaprella Mayer, 1903 a valid genus?
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Detailed morphological studies of the caprellid abdomen are necessary to understand the evolution of this group. According to the diagnosis of the genus Caprella, the abdomen of males is provided with a pair of uni- or bi-articulate appendages and a pair of lobes, and females only have the pair of lobes and lack appendages. However, during a monitoring study of Caprella equilibra in southern Spain, we found that 7% of the females were provided with abdominal appendages, revealing that there is intraspecific variation of the female abdomen, even in the same population. The intrageneric and even intraspecific evidence of morphological variation of the abdominal appendages in Caprella and Metacaprella indicates that the external morphology of these appendages is not an ontogenetically and morphologically stable character to diagnose a genus. Consequently, this study supports the evidence that the abdominal appendage is a polymorphic and symplesiomorphic character in Caprella and Metacaprella, and that Metacaprella is not a valid genus.
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Echthrogaleus mitsukurinae sp. nov. (Copepoda, Siphonostomatoida, Pandaridae) infesting the goblin shark Mitsukurina owstoni Jordan, 1898 in Japanese waters
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Echthrogaleus mitsukurinae sp. nov. (Copepoda, Siphonostomatoida, Pandaridae) is described based on a female recovered from the body surface of the goblin shark, Mitsukurina owstoni Jordan, 1898, captured on the slope of the Tokyo Canyon at about 400 m depth in Tokyo Bay, Japan. This new species is easily distinguishable from all its congeners in having the following unique features in the female: (1) the lateral lobes of the cephalothorax and the lateral plates of pediger 2 are devoid of marginal membranes, (2) the dorsal plates of pediger 4 have a smooth margin, (3) the posterolateral lobes of the genital complex are widely curved medially and overlap each other across the midline, (4) legs 2 and 3 have 3-segmented endopods, and (5) leg 4 has an incompletely 2-segmented exopod.
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An improved mark-recapture method using passive integrated transponder (PIT) tags in Birgus latro (Linnaeus, 1767) (Decapoda, Anomura)
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The effectiveness of Passive Integrated Transponders (PIT tags) was investigated in the robber or coconut crab, Birgus latro. A pilot study was conducted in Chumbe Island, Zanzibar, and a definitive study on Christmas Island, Indian Ocean. No mortality or adverse behaviour was recorded as a result of PIT tagging. On Christmas Island 1150 crabs were tagged in 2009 and 2010. In the period to April 2011, 169 crabs were recaptured, some up to four times. Of these, 67 had moulted before recapture. Approximately equal numbers of each sex were marked, and recaptured. Tag loss was estimated at ~5%. Alternative sampling protocols using grid and transect searches were tested. They produced different results in terms of sampling efficiency and sex ratio: sampling protocol must be considered when interpreting data.PIT tagging in Birgus is a promising method for long term population studies. It promises low tag loss and good recapture rates in comparison with previous studies.
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Spatial structure of the pink speckled deep-sea shrimp Penaeopsis serrata (Bate, 1881) (Decapoda, Penaeidae) during November-December 2009 in the Colombian Caribbean Sea
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The objective of this study is to describe the patterns of abundance in spatial distribution of the pink speckled deep-sea shrimp Penaeopsis serrata (Bate, 1881) in the Colombian Caribbean Sea. Data were collected by trawling at depths between 100 and 550 m. Significant differences between sexes were found, revealing sexual dimorphism; males were smaller than females. The size structure for females showed an increase in relation to depth. The higher biomass of P. serrata was found between 350 and 450 m, which suggests that this species inhabits narrow depth strata. Due to the temporally limited data, we cannot predict the overall vulnerability of the species. Circumannual data are needed to suggest necessary actions of protection, in order to guarantee a sustainable management of P. serrata and conservation of its fisheries.
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On the presence of the caridean shrimp Lysmata vittata (Decapoda, Hippolytidae) in the Russian waters of the Sea of Japan
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Ebalia nux (Decapoda, Brachyura) found among the leaves of Pteroeides spinosum (Anthozoa, Octocorallia)
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