Swimming Crab Ovalipes Research Articles

Effects of dietary administration of two Patagonian probiotics on the zoeae I from the swimming crab Ovalipes trimaculatus

Effects of dietary administration of two Patagonian probiotics on the zoeae I from the swimming crab Ovalipes trimaculatus

Combining fishers' perceptions, landings and an independent survey to evaluate trends in a swimming crab data-poor artisanal fishery

The fishery for the swimming crab Ovalipes trimaculatus in the southwestern Atlantic started in 2007, with an average catch of 64.36 t⋅y−1 during the period between 2008 and 2013. The fishery is under an open access regime and market demand exceeds the catch which raises concern about its future. It is also data-poor, which prevents researchers from using traditional assessment methods. The factors that limit the fishing effort were identified by analyzing the fishing operation, the decision making process of the fishers and CPUE. Changes in catch composition through space and time, and the distribution of the population along a depth gradient were also studied.Wind, recent yield and the price of crab were perceived by skippers as relevant factors when deciding to go fishing, but there was no relationship between these variables and monthly fishing effort. However, daily fishing effort depended on wind conditions. During the studied period (2008–2013) the CPUE of 2009 was the only one lower than the CPUE of 2008, and the number of fishing grounds as well as their respective area have not increased. The species depth distribution reaches 60 m deep, which is much deeper than the depths divers can reach (about 20 m), however the highest abundance of O. trimaculatus occurs at less than 30 m depth. The fishery did not show signs of depletion likely due to the combination of target species depth distribution and fleet characteristics limiting fishers' operability. This provides a unique opportunity to constrain fishing effort and avoid overcapacity, for example by banning larger vessels from the fishery.

Mitochondrial DNA variation in the East China Sea and Yellow Sea populations of swimming crab Ovalipes punctatus

Swimming crab Ovalipes punctatus is a commercially important species in the East China Sea and Yellow Sea, but there is limited knowledge of its genetic population structure. The population genetic structure of O. punctatus in East China Sea and Yellow Sea was examined with a 658-bp segment of the mtDNA COI gene. A total of 60 individuals were collected from five locations and 48 haplotypes were obtained. Mean haplotype diversity and nucleotide diversity for the five populations were 0.9876 ± 0.0068 and 0.0074 ± 0.0041, respectively. Analysis of molecular variance (AMOVA) detected no significant differences at all hierarchical levels, and all FST values were non-significant, indicating that no significant population genetic structure exists in the East China Sea and Yellow Sea. These results supported the null hypothesis that O. punctatus within the East China Sea and Yellow Sea constitutes a panmictic mtDNA gene pool. Neutrality tests and mismatch distribution supported population expansion in this species, indicating that climate change could play an important role in affecting the demographic history of marine species. Strong dispersal capacity of larvae and adults, and ocean currents in the studied area could be the reasons for genetic homogeneity in this species in the East China Sea and Yellow Sea. Another explanation for the lack of phylogeographic structure in O. punctatus might reflect a recent range expansion after the last glacial maximum and insufficient time to attain migration-drift equilibrium.

First report of the swimming crab Ovalipes iridescens (Miers, 1886) (Brachyura, Portunidae) from Taiwan

The portunid crab Ovalipes iridescens (Miers, 1886) is reported for the first time from the marine waters of Taiwan, and is just the second Ovalipes species known from this region. The only previously known Ovalipes species from Taiwan is a commercially-used species, Ovalipes punctatus (De Haan, 1833). The present study provides morphological and distributional data, and discusses the variability of the external morphology. The colour pattern of the body and the shape of the male gonopods of the newly recorded O. iridescens are illustrated.

Mathematical modeling of the heat transfer process and protein denaturation during the thermal treatment of Patagonian marine crabs

Southern Ocean swimming crab Ovalipes trimaculatus and the Patagonian stone crab Platyxanthus patagonicus are fishing resources with commercial value. Thermal treatment of crabs is necessary to denature muscle proteins, facilitating meat detachment from the crab shell (picking procedure). The proximal composition, protein patterns of crab muscle, thermophysical properties and heat transfer coefficients were determined. Heat transfer during thermal processing of body (i.e., cephalothorax) and claws of both crab species was simulated using a finite element computational code; the simulations were experimentally validated. Color changes in crab muscle during the heating process were measured. Thermal denaturation kinetics of myofibrillar proteins was determined using Differential Scanning Calorimetry (DSC) in small samples previously heated in water under controlled conditions. DSC thermograms of raw crab muscle showed two peaks at 49.0±0.4 and 77.5±0.6°C corresponding to myosin and actin respectively. Activation energies for the denaturation of myosin (145.70kJ/mol) and actin (156.42kJ/mol) were calculated from Arrhenius equation. The degree of denaturation achieved by the myofibrillar proteins at the coldest point of the muscle in body and claws during the heating process was established by considering the protein denaturation kinetics determined by DSC, the activation energies and the heat penetration curves. Adequate conditions for the detachment of meat from the crab exoskeleton were established. The obtained results may help in determining the optimal heating times during the industrialization of these crustaceans.

Post‐release predation on hatchery‐reared Japanese flounder Paralichthys olivaceus in the coast of Fukushima, Japan

To determine the predators of 100 mm total length hatchery-reared juvenile Japanese flounder Paralichthys olivaceus, fishes and crabs were collected using gillnets and a small trawl net off the coast of Fukushima Prefecture, Japan. Predation on juvenile P. olivaceus by older conspecifics, the snailfish Liparis tanakai, ocellate spot skate Okamejei kenojei and the swimming crab Ovalipes punctatus, was detected based on analogical observation and molecular techniques. These predators are nocturnal feeders except for P. olivaceus. Liparis tanakai with body sizes large enough to consume juveniles only appeared in winter, whereas the large O. punctatus was abundant in early summer and in late autumn. Such seasonal variation in predator abundance indicates that the release season can be optimized for reducing predation mortality.

Size Relationships and Relative Growth of the New Zealand Swimming Crab Ovalipes catharus (White, 1843)

Size Relationships and Relative Growth of the New Zealand Swimming Crab Ovalipes catharus (White, 1843)

87:6515 Size relationships and relative growth of the New Zealand swimming crab Ovalipes catharus (White, 1843) : Davidson, R.J. and I.D. Marsden, 1987. J. crustacean Biol., 7(2):308–317. Zool. Dept., Univ. of Canterbury, Private Bay, Christchurch 1, New Zealand

87:6515 Size relationships and relative growth of the New Zealand swimming crab Ovalipes catharus (White, 1843) : Davidson, R.J. and I.D. Marsden, 1987. J. crustacean Biol., 7(2):308–317. Zool. Dept., Univ. of Canterbury, Private Bay, Christchurch 1, New Zealand

SIZE RELATIONSHIPS AND RELATIVE GROWTH OF THE NEW ZEALAND SWIMMING CRAB OVALIPES CATHARUS (WHITE, 1843)

Relative growth of the swimming crab Ovalipes catharus was described from measurements made on the carapace, abdomen, gonopod, and chelipeds using carapace width (cw) as the reference dimension. Log-transformed regressions were used to test for allometric growth and lines were compared by ANCOVA. No significant difference was found in the growth of the carapace for male and female crabs and relative growth in carapace length was negatively allometric. Abdomen growth in female 0. catharus showed a discontinuity between 35 and 40 mm cw indicating the pubertal molt. For prepubertal females and males, abdomen growth was isometric, contrasting with postpubertal females where abdomen growth was positively allometric. Male crabs between 15 and 100 mm cw showed positive allometric growth of the gonopod with a discontinuity corresponding to a carapace width of 40 mm. Relative growth of the gonopod of immature males was significantly greater than mature males. In 0. catharus the right chela or crusher was enlarged compared with the left chela. Relative growth of chela height in females was isometric and in males, negatively allometric. For female 0. catharus it was concluded that major differences in allometric growth were related to the onset of sexual maturity and the maturation of the gonads. Differences in the allometric growth of the male gonopod and male chelae are more likely related to mating or other behavioral adaptations.

Distribution of the portunid crabOvalipes punctatus(De Haan) in Algoa Bay and salinity and temperature tolerances of its zoeae

The three-spot swimming crab Ovalipes punctatus is commonly found in surf zones off sandy beaches in Algoa Bay. It is exclusively marine and occurs down to a depth of 38 m. Large crabs were found close inshore while smaller crabs were predominantly found in deeper water, suggesting that settlement mainly occurs offshore in water 25 – 38 m deep. Gravid females were found closer inshore in shallow water. The zoeae could not tolerate high temperatures (>27,5 °C) or low salinities (<15‰). The optimal temperatures and salinities for survival of the zoeae were 15–22 °C and 34–35‰ respectively.

Seasonal changes in biochemical composition and energy content of the three-spot swimming crab Ovalipespunctatus(De Haan) (Crustacea:Brachyura)

The biochemical composition of the three-spot swimming crab Ovalipes punctatus (De Haan) fluctuated during the period of investigation, probably due to the large variation between individuals and the absence of a distinct breeding cycle. In the females there was a build-up of protein and lipid before the main breeding period. The mean values for protein (35.0%), lipid (2.9%), carbohydrate (11.53%) and ash (49.55%) expressed on a dry-wt basis are similar to values for other Brachyura. The mean energy values for males and females were 10.42 kJ · g −1 and 10.88 kJ · g −1 respectively, with high values for the females during the main breeding period due to gonad development. Analyses of the exuvium revealed low energy (2.94 kJ · g −1) content due to high (92.11%) ash content. Results are discussed in relation to the breeding cycle and moulting period of the crabs.