Browse results

You are looking at 1 - 10 of 601 items for :

  • Carcinology x
  • Primary Language: eng x
  • Search level: All x
Clear All

Abstract

An abnormal bifid rostrum is reported for the first time for a wild-caught subadult female (carapace length = 22.5 mm) of the pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) from Celestun lagoon, Yucatan, southern Gulf of Mexico. A review of registers on morphological abnormalities in shrimps of the family Penaeidae is provided.

In: Crustaceana

Abstract

In this study we examined the morphological anomalies of 2023 ovigerous females of the copepod Eurytemora affinis from laboratory and field samples. Field copepod collections were collected from 10 sites in Europe and North America. Laboratory cultured copepods were reared at 6 experimental conditions during several generations. The observation under the microscope of the ovigerous females’ bodies revealed the presence of a ‘Tumor Like Anomaly’ (TLA) on a few individuals, which were manifested on the urosome. The occurrence of TLA was only noticed on copepods from the field samples. This result shows that under controlled laboratory conditions, E. affinis do not manifest any abnormal morphology, even when temperature and salinity conditions are stressful, which also demonstrates the high plasticity of this copepod species and its capacity to live at a wide range of environmental parameters. In this study, we also confirmed that E. affinis is capable of producing eggs with a wide range of sizes, ranging from very small and abnormal eggs of 75.79 μm only, to very large eggs, reaching a maximal diameter of 128.71 μm. The observed large eggs are abnormal compared to the average size of the other eggs produced within the same clutch. Other abnormalities on eggs, such as deformed eggs or eggs infested by fungi, are only observed from field samples at a few sampling sites. In the Seine estuary, several abnormalities in eggs and adult females were observed during February 2010. The critical period for E. affinis’ development is sampling site-specific and needs to be accurately studied in the future to better explain the causes of the abnormalities described in this work, and their effects at population level.

In: Crustaceana
Author:

Abstract

A new genus and species of gecarcinucid crab are described here from the Namdapha Tiger Reserve of Arunachal Pradesh, India; Abortelphusa namdaphaensis gen. et sp. nov. is morphologically distinct from other related genera, like Phricotelphusa Alcock, 1909, Globitelphusa Alcock, 1909, Liotelphusa Alcock, 1909, and in having a discrete suite of characters, i.e., carapace squarish, surface randomly pitted, a wide frontal margin ca. 0.5 times the total carapace width; epigastric cristae rugose, post orbital cristae indiscernible; third maxilliped exopod lacking a flagellum; male pleon narrowly triangular, sixth pleonal somite trapezoidal; terminal segment of male first gonopod subcylindrical, outwardly bent, tip not truncated. The relationship of this new genus and species with other gecarcinucid genera from India is discussed.

In: Crustaceana

Abstract

We studied the morphology of Eurytemora from inland waters at the shores of the White and Pechora seas and from the Lena River delta, and revealed a ubiquitous presence of Eurytemora gracilicauda Akatova, which results we confirmed with genetic data. We found this species for the first time in the Pechora Sea basin. In the White Sea basin, this species was previously described as E. brodskyi Kos, with the name that we suggest is a junior synonym of E. gracilicauda. E. gracilicauda differs from the co-living species: E. lacustris (Poppe), E. arctica Wilson M. S. & Tash, and E. raboti Richard, by the structure and armament of the caudal rami and the fifth legs (P5) of males and females. The caudal rami of both males and females were elongated. The female caudal rami showed a surface covered by spines. The male caudal rami were bare, or with rare spines on the sides. The appendages of the female P5 were also elongated: the length of the inner spine on the distal exopod segment was 2.27 ± 0.12 times as long as the outer spine; the exopod of the male right P5 had a specific trigonal ledge with a short spinule, and the coxopods (both or at least one) had groups of spinules. The morphometric parameters of the females were quite stable, while those of the male showed high variability within and between populations (CV = 11.5-43.5%). Similarities and differences of E. gracilicauda and three allochoric Eurytemora species were analysed, and the results presented herein.

In: Crustaceana

Abstract

The blue crab Callinectes sapidus is an alien decapod established in the Mediterranean Sea. Since 2007, increased abundance has been reported from the northern Aegean Sea sustaining local scale fishery. The present work aims to assess the abundance and population structure of C. sapidus in Thermaikos Gulf using fyke nets. Population abundance, estimated as CPUE, exhibited strong temporal variability with decreased values in the cold season; this pattern was correlated with seawater temperature. Females exhibited also spatial differences with increased abundance close to the Aliakmon estuary. In total, 543 individuals were measured for carapace width. Males prevailed in the population; however, mean size was similar between sexes. Larger individuals were caught from deeper waters and the estuarine areas, whereas mean size decreased temporally. The fyke nets used proved to be size-selective, thus preventing fisheries mortality for juveniles. However, recurrent monitoring is necessary for a sustainable management of blue crab fisheries in the gulf.

In: Crustaceana

Abstract

The common method of using lobster-pot catch data for investigating relative abundance, sex and size distribution has serious disadvantages. This study estimates relative abundance and size of the European lobster Homarus gammarus and the brown crab Cancer pagurus using scuba diving techniques. The study areas were the Kåvra lobster reserve (Kåvra) on the Swedish west coast and three very different nearby areas where fishing for crustaceans is allowed: Gullmarsfjorden; the archipelago; and the offshore area. A total of 167 lobsters and 337 brown crabs were observed during 33 scuba dives (each 30 minutes long) in 2018-2019. The estimated mean abundance of lobsters was three to fifteen times as high at Kåvra in comparison with the other three areas (all exact p < 0.003 showing that the statistical populations were distinct in comparison with Kåvra; Wilcoxon-Mann-Whitney Test). Dive sites in the outer part of the offshore area had the lowest abundance of lobsters although they had seemingly good lobster habitats and low fishing intensity. Large lobsters with a carapace length of ⩾15 cm were found only at Kåvra where they made up 24% of the lobsters. The proportion of large lobsters inside Kåvra continues to increase after 30 years of protection. Together, this emphasizes the impact of fishing on lobster abundance and size distribution, and indicates that limited recruitment and migration might possibly affect offshore lobster “sub populations”. Kåvra was the only area where the abundance of lobsters exceeded the abundance of brown crabs ( p = 0.039 ). However, the abundance of brown crabs at Kåvra was as low as in Gullmarsfjorden ( p = 0.42 ) where fishing for crabs is allowed. Possible complex lobster/brown crab interactions together with other factors that might explain the low abundance of the protected brown crab at Kåvra, need to be investigated further.

In: Crustaceana

Abstract

The presence of the calanoid copepod Boeckella gracilis (Daday, 1902) in Chilean seasonal pools has been only poorly studied as yet. The aim of the present study thus is to investigate the role of conductivity and temperature on the relative and absolute abundance of B. gracilis in seasonal coastal pools in the Araucania region (38°S, Chile). The results of correlation analysis revealed the presence of a significant inverse correlation between conductivity and relative abundance, whereas no significant correlations were found between conductivity and absolute abundance, between temperature and absolute abundance, and between temperature and relative abundance. These results agree partially with similar observations for mountain pools in the same region, but they would not agree with observations for calanoids of saline and subsaline inland waters in the northern and southern extremes of Chile. Considering this scenario, the species would show different populational responses to environmental stress in different situations, which phenomenon deserves to be studied more extensively and in more detail.

In: Crustaceana

Abstract

Na+/K+-ATPase is an important ion-transporting enzyme involved in osmoregulation. The swimming crab (Portunus trituberculatus) is a commercially important edible crab species in China. At salinities lower than 10 or higher than 40 , its production is seriously impacted; however, the mechanisms of how the Na+/K+-ATPase of swimming crabs responds to salinity changes, is unclear. In the current study, the Na+/K+-ATPase α-subunit (NAKA) and β-subunit (NAKB) cDNA of P. trituberculatus was identified. Multiple alignment was performed and the expression of NAKA and NAKB in the 6th gills under different salinity conditions were detected using semi-quantitative RT-PCR. The results showed that NAKA and NAKB mRNA both increased significantly at day 1, but they were maintained at low levels when exposed to 40 salinity for a long time. The hematoxylin and eosin staining showed that ionocytes increased in size at 40 salinity, but decreased at 10 salinity. Immunocytochemical analysis revealed that NAKA signals increased with exposure to 40 salinity for one day, but the signals were not strong at 10 salinity. Comparison of the conserved NAKA domain of P. trituberculatus and the Chinese mitten crab (Eriocheir sinensis) showed that the polypeptide binding site (α-subunit/β-subunit interface) was different, which may be one of the reasons that P. trituberculatus is not as tolerant of fresh water as E. sinensis.

In: Crustaceana

Abstract

The two spiny lobster fisheries targeting Panulirus argus (Latreille, 1804) and Panulirus laevicauda (Latreille, 1817) have made an important marine resource in Northeast Brazil since 1955. The Von Bertalanffy age and growth parameters of the spiny lobster started being studied in 1960 and the last assessment was performed over 20 years ago. The objective of this review is to analyse the type of input data and the methods historically used to assess age and growth of the spiny lobster stock in Northeast Brazil.

Our study reviews and updates the research on the subject and proposes relative values for the Von Bertalanffy growth parameters for P. argus and P. laevicauda as provisional reference. We recommend further age and growth research on spiny lobsters to create a new and updated growth function for commercial lobsters in Northeast Brazil.

In: Crustaceana