Non-ovigerous Females Research Articles

Female reproductive status affecting chimney characteristics and time allocation for surface activities in Uca rosea (Tweedie, 1937) (Brachyura, Ocypodidae)

We examined the effects of female reproductive status (ovigerous and non-ovigerous) on chimney characteristics and time allocation for surface activities in Uca rosea (Tweedie, 1937) (currently referred to as Tubuca rosea (Tweedie, 1937)). We investigated time spent on feeding, standing, in burrow, surface mating, walking, grooming, and digging of 13 ovigerous and 20 non-ovigerous females of similar-size and measured the diameter, width, and height of their chimneys. Chimneys of ovigerous females were wider and higher than those of non-ovigerous females, but chimney diameters did not differ. Ovigerous females spent less time on feeding and walking, but more time on standing, inside burrows, and mating than non-ovigerous females. Feeding rate/min did not differ between ovigerous and non-ovigerous females. This study reports, for the first time, that reproductive status of females affects chimney characteristics and time allocation for surface activities in U. rosea.

Reproductive aspects of the shrimp Cuapetes americanus (Kingsley, 1878) (Caridea, Palaemonidae) from Bocas del Toro, Panama

The shrimp Cuapetes americanus is widely distributed in shallow waters of the western Atlantic Ocean, inhabiting sandy and rocky bottoms, macroalgae, seagrass beds, and mangrove roots. As the life cycle and ecology of this species remain poorly known, we investigated some reproductive traits of this species at Bocas del Toro, Panama. We collected and examined 167 individuals (63 males, 58 non-ovigerous females and 46 ovigerous females). Although males numerically dominated the larger size classes, ovigerous females were significantly larger than males and non-ovigerous females. All 46 ovigerous females were used to calculate embryo loss and embryo volume increase. Only females with eggs at an initial developmental stage () were used to estimate fecundity and reproductive output. A mean of 75.84 ± 40.16 embryos () occurred per female, a value near those reported for other species of Pontoniinae. A positive correlation between fecundity and female body size was observed, but it lacked significance. Likewise, a significant correlation between female body size and embryo volume was not detected. Embryo volume increased 35%, and females lost 26% of embryos on average during the incubation period, though significant changes were measurable only during early embryonic development. Mean reproductive output in the analysed reproductive event (0.22 ± 0.11, ) suggested a rate of energy investment in reproduction higher than average, as compared to females of most other decapods. A decrease in relative reproductive output was observed with the increase of female size, indicating that larger females were investing proportionally less energy in reproduction than smaller ones, when measured in relation to the body size, but this correlation also lacked significance. We review how these initial insights on reproduction of C. americanus at Bocas del Toro compare to those of other populations in various localities.

Locomotor activity pattern in pairs of the subsocial desert isopod Hemilepistus reaumurii

Locomotor activity rhythm of fresh adult of H. reaumurii was recorded in pairs with ovigerous and with non-ovigerous females. According to double-plotted actograms and waveform curves, results showed the presence of different locomotor patterns. In fact, locomotor profiles of pairs with ovigerous females were mainly bimodal whatever the recording conditions, whereas locomotor patterns were trimodal in pairs with non-ovigerous females. Results showed also that locomotor activity rhythm was more stable in the presence of the synchronizer (nLD cycle) than in constant darkness whatever the recording type. Moreover, the most important stability of the locomotor rhythm was observed under constant darkness and individuals were more active in pairs with ovigerous females than in pairs with non-ovigerous females.

Bycatch of the Southern King Crab (Lithodes santolla) in the Patagonian shrimp fishery in the Southwestern Atlantic Ocean. Can it contribute to the depletion of its population?

The Southern King Crab (SKC), Lithodes santolla, has supported a growing fishery in San Jorge Gulf (Patagonia, Argentina) since 2011. This fishery is developed by vessels called crabbers. SKC is also caught as bycatch in the Patagonian shrimp fishery, a major crustacean fishery in the Southwestern Atlantic Ocean. In this work, we characterized SKC bycatch in shrimp fishery and compared 1994–1996 data (which reflected little fishing impact) and 2011–2012 data (at the beginning of the current SKC fishery by crabbers in San Jorge Gulf), to determine the particular effects of bycatch on the SKC population. The frequency of occurrence of SKC in shrimp hauls was 84.08%. However, the relative abundance was low, in most of the hauls SCK represented less than 5% of the capture. Between 2006 and 2011, the estimated SKC bycatch was 2432 tn/year. Frequency of occurrence and abundance were higher in the same area where crabbers operate. SKC bycatch is commonly discarded, but, in 18% of the hauls, SKC are processed on board, although this is illegal. Mortality estimated at the beginning of handling was 19%, but this value may be greater due to the long time of onboard handling. SKC bycatch include critic stages of its life cycle such as juveniles, ovigerous females and molting individuals. Juveniles represented 26.9% of the total SKC bycatch, while ovigerous females represented 28.1%. Sex ratios and male size showed no differences between 1994–1996 and 2011–2012, whereas the proportion of ovigerous females decreased between both periods. This decrease can be related to the interference of trawlings in their reproductive migration to coastal waters or in their mating grounds. We consider that the main problem of SKC bycatch is the detrimental effects on its reproductive potential due to the increase in the proportion of non-ovigerous females and the mortality of ovigerous females along with extensive handling, which can also result in a significant egg loss.

Population biology and morphometric sexual maturity of the fiddler crab Uca (Uca) maracoani (Latreille, 1802) (Crustacea: Decapoda: Ocypodidae) in a semiarid tropical estuary of northeastern Brazil

The population biology and size at sexual maturity of Uca (Uca) maracoani were studied for the first time in a semi-arid tropical estuary of northeastern Brazil. A catch-per-unit-effort (CPUE) technique was used to sample the crabs, on the surface and inside burrows, for 60-min sampling periods by one person on a monthly basis during spring low tide periods from June 2013 to June 2014 in an estuary area of Baixa Grande Beach. A total of 406 crabs were obtained, of which 317 were males, 87 non-ovigerous females, and two ovigerous females. Males were larger than non-ovigerous females. The U. (U.) maracoani population presented unimodal size frequency distribution, which may reflect a continuous recruitment, with no disruption of classes and constant mortality rates, indicating a stable population. The overall sex ratio (3.5 males: 1 female) differed significantly from the expected 1:1 proportion. The major cheliped was on the right side in 45.1% of the males, as reported for other fiddler crabs populations. A total of 294 males and 89 females were used in the allometric study. The specimens were measured at carapace width (CW), the major propodus length (MPL) of males, and abdomen width (AW) of females. In males, the relationship between CW and MPL was 22.3 mm CW, which is considered the functional value at maturity. In females, the size at sexual maturity was 19.3 mm CW based on the relationship between CW and AW. The CPUE method is discussed as one of the reasons of the high sex ratio skewed towards males. This is the first account regarding population structure of U. (U.) maracoani in semi-arid tropical areas.

Life history of Dulichiella appendiculata (Amphipoda, Senticaudata, Melitidae) in Maryland Coastal Bays, USA

Epibenthic samples collected from March to December 2012 (except September) in Maryland Coastal Bays (MCBs) were used to study the reproductive biology of Dulichiella appen- diculata, an amphipod species common in estuaries of the Atlantic and Gulf coasts of the USA, whose life history is not well known. Mean densities (± SE) of D. appendiculata increased from May to July, and declined thereafter. The species reproduced continuously from April (spring) to October (fall). The proportions of ovigerous to non-ovigerous females increased with temperature, from ~70% (April), when mean water temperature was 14.7 ± 0.77°C, to ~94% (July), when water temperature was at its peak (26.4 ± 0.23°C), before decreasing to 0% (November) when the temperature was 9.6 ± 0.2°C. The maximum body lengths of non-ovigerous (9.75 mm) and ovigerous (9.85 mm) females, and males (11.1 mm) were larger than values previously reported in a D. appendiculata population in Beaufort, North Carolina, USA. Large ovigerous females from an overwintering cohort produced juveniles in April, and then disappeared from the population by June, leaving behind small, less fecund ovigerous females belonging to a new generation to pro- duce juveniles. Thus, ovigerous females were smaller in size in June (mean ± SE: 4.8 ± 0.2 mm) than in April (7.3 ± 0.1 mm) and May (8.8 ± 0.5 mm). Males outnumbered females from May to October, but the reverse was the case in April (p < 0.05). The D. appendiculata population in MCBs has a semi-annual, iteroparous life history, with a longevity of about 6 mo (spring breeder) and 9 mo (fall breeder).

Feeding habits of blue swimming crab Portunus segnis (Forskal, 1775) in the northern coastal waters of Iran

The study of food and feeding habits of crab has manifold importance in fishery sciences. The blue swimming crab Portunus segnis is an opportunistic predator and the diet of which depends on local availability of food items. The distribution and biological aspects of crabs are largely dependent on the availability of preferred prey organisms. Feeding habits of the blue swimming crab, P. segnis were studied in the northern Persian Gulf by trawl nets during the period from May 2010 to April 2012. The stomach contents of 1722 crabs, ranging from 36 to 175 mm carapace width, were analyzed. The stomach contents appeared to consist of mainly large quantities crustaceans, fish and molluscs, also small quantities of unidentifiable matter and debris. Based on the major food groups were observed in different season, the crustaceans was the most dominant in summer (56 %) and the fish items and Mollusca were the most dominant in autumn (67 %) and winter (45 %) respectively. In Juvenile and sub adult crabs, crustaceans constituted the dominant food source and these were present in 56.7 % and 45.1 % respectively. In the adult groups and larger size groups, fish were the principal food item and these were present in 44.5 % and 53.5 % respectively, of the stomachs analyzed. There were no difference observed in the quantity of the food consumed in both sexes and also significant differences observed in the preference for food items in the different size groups. The crabs without barnacle comparatively voracious with barnacle-carrying crabs. Their diet also increased with increasing ovary stages while that the percentage of empty stomachs in ovigerous females was higher than non-ovigerous females. The C.V. index varied significantly in both sex that was ranged between 6.9- 56.0 % and 16.5- 48.0 % for male and female, respectively. This study shows that, despite the diversity in blue crab diets and feeding habits, there are carnivores with a preference for animal food and the behavior of active predators of sessile and slow-moving macro-invertebrates. It is suggested that a major reduction in availability of one prey group would not have a major effect on the crab population.

Selectivity of Two Methods for Surveying the Japanese Mitten Crab, Eriocheir Japonica (De Haan, 1835), in a Riverine Environment

Differences between the results of pot fishing and hand-net collecting of the Japanese mitten crab, Eriocheir japonica (De Haan, 1835), were examined to increase the accuracy of sampling natural population in freshwater and tidal areas of a small river. Large adult crabs were caught in pots; small juveniles mostly collected with the hand nets. The difference in size composition in the freshwater river is probably caused by changes in the dietary preferences and behaviors that occur as crabs grow larger. The sex ratio was strongly male-biased in pot fishing in the tidal river in contrast to hand-net collecting (no bias), and males captured in the pots were slightly larger than those caught by hand-nets. The sex ratio bias observed in pot fishing in the tidal river can be explained by mating behavior, whereas the differences in the size of males between the two methods can be explained by the dimorphism and alternative mating strategy of male E. japonica . The proportions of ovigerous females in the tidal river in early winter were larger in pot than in hand-net samples. Differences in the proportion of ovigerous females between the two gears in the tidal river may have resulted from the presence of two groups differing in reproductive season and the wandering activities of ovigerous and non-ovigerous females. Although pot fishing is useful for studying reproductive ecology, the resulting data is sometimes strongly biased. In contrast, hand-net collecting is essential for gathering a complete range of crabs from all size classes and the data generated by this method is more representative of their distribution pattern. It is necessary to make up for the shortcoming of each sampling method.

An investigation on some biological and reproduction characteristics ofEriphia verrucosa (Forskål, 1775) in the South Black Sea (Turkey)

In this study, a total of 1360 specimens of Eriphia verrucosa were collected from the South Black Sea region of Turkey between February 2012 and January 2013 to determine their biological and reproductive characteristics. The overall sex ratio of all individuals was calculated as 1:0.42 (M/F). The mean carapace width was determined as 6.76, 5.57, and 5.62 cm for males, nonovigerous, and ovigerous females, respectively. The minimum and maximum weight was recorded as 4.07 and 301.4 g for both sexes. The highest correlation between morphological characteristics was determined for carapace length and crab weight in nonovigerous females (R2 = 0.973; N = 317). The percentage of ovigerous females was 6.25% and they were observed only between May 2012 and August 2012. The mean fecundity was calculated as 89,129 ± 8005 eggs. The egg diameter ranged from 499.0 to 701.7 µm with a mean value of 546.36 ± 18.62 µm for stage I, 606.92 ± 15.92 µm for stage II, and 570.96 ± 9.22 µm for stage III.

Estructura de la población del cangrejo rey Damithrax spinosissimus en el Caribe colombiano

&lt;p&gt;El estudio biológico y de población del cangrejo rey Damithrax spinosissimus es fundamental para establecer los planes de manejo de esta especie en el Caribe colombiano. Este estudio brinda información sobre las tallas, la proporción entre sexos y las relaciones biométricas de D. spinosissimus en tres islas del Caribe colombiano (Providencia, Rosario y Tintipán), la cual se recogió en muestreos mensuales llevados a cabo entre septiembre de 2011 y marzo de 2012. Se recolectaron 462 ejemplares en las islas. La proporción de sexos fue de 1:1, con 51,5 % de hembras y 48,4 % de machos. La proporción de hembras ovadas con respecto a las no ovadas también fue de 1:1. El promedio de la longitud del caparazón (LC) fue de 11,6 cm tanto en machos como en hembras, mientras que el ancho del caparazón (AC) fue de 11,9 cm en las hembras y de 12,1 cm en los machos. La longitud promedio del caparazón fue de 13,67±1,18 cm en Providencia, de 10,25±1,34 cm en Islas del Rosario y de 10,4 ± 1,14 cm en Tintipán. La relación entre la longitud y el ancho del caparazón se describió mediante la ecuación LC=-0,393186+1,06755*AC, mientras que la relación entre el peso total (P) y la longitud del caparazón se describió mediante la ecuación Ln P=-1,64254+3,36711 Ln LC.&lt;/p&gt;

Effects of Multi-metal (Cu, Zn, Cd, Cr, and Mn) Mixtures on the Reproduction of Freshwater Rotifer Brachionus calyciflorus.

In the field, organisms are usually exposed to mixtures of various metals. However, the effects of multi-metal mixtures on growth and reproduction of rotifers remain unknown. In the present study, effects of multi-metal mixtures (Cu, Zn, Cd, Cr, and Mn) on reproduction of the freshwater rotifer Brachionus calyciflorus were assessed by determining various endpoints, including the ratio of ovigerous females to nonovigerous females, the ratio of mictic to amictic females, the mictic rate, the fertilization rate, the population growth rate, and the resting eggs production. The results demonstrated that reproduction of rotifers was significantly affected by all multi-metal mixtures assessed. Moreover, the ratio of mictic to amictic females was the most sensitive endpoint and might be suitable to evaluate effects of multi-metal mixtures to rotifers.

Egg Production Constrains Chemical Defenses in a Neotropical Arachnid.

Female investment in large eggs increases the demand for fatty acids, which are allocated for yolk production. Since the biosynthetic pathway leading to fatty acids uses the same precursors used in the formation of polyketides, allocation trade-offs are expected to emerge. Therefore, egg production should constrain the investment in chemical defenses based on polyketides, such as benzoquinones. We tested this hypothesis using the harvestman Acutiosoma longipes, which produces large eggs and releases benzoquinones as chemical defense. We predicted that the amount of secretion released by ovigerous females (OFs) would be smaller than that of non-ovigerous females (NOF). We also conducted a series of bioassays in the field and in the laboratory to test whether egg production renders OFs more vulnerable to predation. OFs produce less secretion than NOFs, which is congruent with the hypothesis that egg production constrains the investment in chemical defenses. Results of the bioassays show that the secretion released by OFs is less effective in deterring potential predators (ants and spiders) than the secretion released by NOFs. In conclusion, females allocate resources to chemical defenses in a way that preserves a primary biological function related to reproduction. However, the trade-off between egg and secretion production makes OFs vulnerable to predators. We suggest that egg production is a critical moment in the life of harvestman females, representing perhaps the highest cost of reproduction in the group.

Intra-specific competition drives variation in the fundamental and realized niches of the hermit crab, &lt;I&gt;Pagurus criniticornis&lt;/I&gt;

The difference between preferred and available resources within natural environments can be viewed as the disparity between fundamental and realized niches. We employ this concept to examine intra-specific sexual variation in the shell-size relationships of the hermit crab Pagurus criniticornis (Dana, 1852) from two treatments: (1) a natural unbiased population (i.e., realized niche); and (2) a group subjected to free-choice experiments that were able to select a preferred shell from a selection of high-quality shells (i.e., fundamental niche). Crab-shell relationships for both treatments suggest that males and females select shells proportional to their size. The relationships between crab size and preferred shell weight (i.e., fundamental niche) derived from free-choice experiments enabled the calculation of a shell adequacy index (SAI) for all individuals from both treatments. A strong interaction between SAI values across sex and treatment (♂Free choice = ♀Free choice = ♂Population > ♀Population) suggested that non-ovigerous females may experience a considerable niche disparity in their natural habitats while ovigerous females tend to inhabit shells with a greater prevalence of damaged shell apices. Results suggest a competitive hierarchy whereby males out- compete females for access to high-quality shells. Despite niche disparities, P. criniticornis typically occupied shells of good condition (low damage and encrustation), suggesting that resource limitation may not be as severe as that reported for other hermit crab populations. Our data provide insights into intra-specific competition that reflect the ability of individuals to win and hold high-quality resources within resource-limiting environments.

Seasonal movements of American lobsters in southern Gulf of Maine coastal waters: patterns, environmental triggers, and implications for larval release

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 524:197-211 (2015) - DOI: https://doi.org/10.3354/meps11192 Seasonal movements of American lobsters in southern Gulf of Maine coastal waters: patterns, environmental triggers, and implications for larval release Jason S. Goldstein*, Winsor H. Watson III University of New Hampshire, Department of Biological Sciences, 46 College Road, Durham, New Hampshire 03824, USA *Corresponding author: jsgoldstein2@gmail.com ABSTRACT: American lobsters Homarus americanus are known to move offshore during the fall-to-winter transition and inshore, into shallower, warmer water in the spring and summer. To determine whether all types of lobsters in New Hampshire coastal waters exhibit this movement pattern, we fitted 45 lobsters (ovigerous and non-ovigerous females, and males) with ultrasonic transmitters and tracked their movements over 3 successive seasons from 2006 to 2009. The major goals of this study were to determine (1) if ovigerous females express different seasonal movement patterns than males or non-ovigerous females; (2) what environmental cues might trigger offshore movements in the fall; and (3) the location of ovigerous females when their eggs hatch in the spring-summer. Most lobsters (82%) moved >0.5 km, whereas the rest remained close to their original release location. Of the lobsters that moved, 51% moved <5 km, 19% moved 5-10 km, and 30% moved >10 km. There were no significant differences in the seasonal movements of ovigerous females compared with non-ovigerous females, but females as a group moved significantly farther than males. The ovigerous lobsters that moved offshore tended to remain there until the time when their eggs most likely hatched. In conclusion, the seasonal movements of ovigerous lobsters in coastal waters significantly influence the location and timing of larval hatch and, ultimately, settlement. KEY WORDS: Acoustic telemetry · Seasonal movements · Ovigerous lobsters · Larval dispersal · Homarus americanus Full text in pdf format PreviousNextCite this article as: Goldstein JS, Watson WH III (2015) Seasonal movements of American lobsters in southern Gulf of Maine coastal waters: patterns, environmental triggers, and implications for larval release. Mar Ecol Prog Ser 524:197-211. https://doi.org/10.3354/meps11192 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 524. Online publication date: March 30, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.

Abundance, relative growth and fecundity of Emerita rathbunae Schmitt, 1935 (Decapoda, Anomura, Hippidae) in the S.E. Gulf of California, Mexico

Specimens of the mole crabEmerita rathbunaeSchmitt, 1935, were collected during a one-year period along two sandy beaches in the S.E. Gulf of California, Mexico. A total of 2171 specimens were examined. Only 8% of the collected females were ovigerous. The large majority of males (95%) were collected in the sand as “free living” males, while the rest (39 individuals) were “dwarf males”, with developed genital papilla, 95% of which were found attached to females. Density for pooled samples reached an overall maximum of 309.8 orgs/m2in February and a minimum in April (65.0 orgs/m2). Females always outnumbered males, except in February. Ovigerous females were observed in the first half of the study period (February to September). Proportions of males were very similar throughout the study period, while indeterminate specimens were proportionally more abundant in its second half. Relationships between CW and CL for both males and females were highly correlated and isometric. Relationships between size and weight were highly correlated in both males and non-ovigerous females for pooled samples or for each sampling zone, and in each case growth was isometric. The number of eggs per ovigerous female varied considerably, from 910 to 22 866, and the relationship between number of eggs per batch and body size was poorly correlated. In the study area,E. rathbunaeappears to have a rather restricted reproduction period. A larger series of data combined with the analysis of other environmental factors, such as beach profiles, current patterns and primary productivity, might bring some additional information on this species biology and ecology. Due to the key role that mole crabs play in the food web of sandy beaches, special attention should be provided to this particular habitat.

The effect of steroid hormone feeds on the reproductive biology of the spiny lobster, Panulirus interruptus (J. W. Randall, 1840) (Decapoda, Palinura)

In this study, the effects of adding steroid hormones to the feeds administered to cultures of the spiny lobster, Panulirus interruptus (J. W. Randall, 1840), were investigated. The results indicate that the addition of steroid hormones in the feeds evoke (1) an increase in the ratio of ovigerous versus non-ovigerous females of up to 13.68% as compared to the controls; (2) fertilized females were present several months longer in the treatment group than in the control group; and (3) the ovigerous period, i.e., the time from fertilization until release of the young, was substantially shorter under a regime of feeding with steroid hormone additions. As a conclusion, enrichment of the feeds with steroid hormones thus distinctly increases the yield of young spiny lobsters in the course of a year cycle.

Biological traits of Cyzicus grubei (Crustacea, Spinicaudata, Cyzicidae) in south-western Iberian Peninsula

2 In this study, characteristics of the biology of the spinicaudatan Cyzicus grubei were determined from a population in a temporary pond in the south-western Iberian Peninsula from January 2011 to July 2011. The results indicated the existence of a single cohort for the duration of the flooding period. Non-ovigerous females and males were present in the pond throughout the study period. However, ovigerous females were present from mid-April to early July. Males had valves significantly larger and higher than females. The relationship between the valve length and the valve height showed positive allometry in males and negative allometry in females and the whole population (mature and immature individuals). The smallest mature male was 8.13 mm in valve length, whereas the smallest ovigerous female was 8.21 mm in valve length. Females outnumbered males in winter and early spring, and males were more abundant in late spring and early summer. The mean number of eggs on ovigerous females was 574.74±245.29, ranging from 241 to 1068 eggs/female. The number of eggs was linearly correlated with the valve length of the female.

Assessment of reproductive capacity in females of Callinectes danae Smith, 1869 (Brachyura, Portunoidea) during a period of high reproductive activity

The reproductive capacity of the swimming crab Callinectes danae Smith, 1869 was assessed based on the reproductive investment (RI) of ovigerous females and the gonadosomatic index (GI) of non-ovigerous adult females. Crabs were collected in June 2009 with a shrimp fishing boat at Ubatuba (23° 26′S 45° 02′W) São Paulo, Brazil. Overall, 191 adult females were analyzed, of which 108 were ovigerous and 83 non-ovigerous. The size of ovigerous females ranged from 54.5 to 79.8 mm carapace width (CW) and non-ovigerous females ranged from 56.0 to 80.9 mm CW. RI values did not differ among the size classes (ANOVA, p > 0.05), with an overall mean of 15.8%. The same occurred with the Gonadossomatic index for non-ovigerous females, for which the mean value was 11.7%. The regression between the dry weight of the egg mass and the dry weight of the crab (Student’s t, p = 0.25; ttab = 1.66; tcal = 0.66) indicated an isometric relationship for the variables analyzed. The simultaneous occurrence of gonadal maturation and embryonic development in ovigerous females suggests that these crabs may spawn at least twice in the same breeding season and reveals the need for evaluation of the allocation of energy in subsequent spawns.

Sex and reproductive stage differences in the growth, metabolism, feed, fecal production, excretion and energy budget of the Amazon River prawn (Macrobrachium amazonicum)

The aim of this study was to evaluate differences in various physiological measures (growth, fecal production, feed intake, nitrogenous excretion, oxygen consumption, energy substrate used, and energy budget) among males, ovigerous females and non-ovigerous females of the freshwater prawn Macrobrachium amazonicum. This species exhibits pronounced sexual dimorphism and different male morphotypes and has the potential for use in aquaculture. Males and non-ovigerous females were studied for 30 days. Ovigerous females were studied for 10 days. Prawns were fed commercial prawn food, and all males were of the Translucent Claw (TC) morphotype. The results demonstrate physiological differences both between males and females and between females of different reproductive stages. Males had higher rates of ingestion, growth and oxygen consumption and less fecal loss than females. We postulate that in the absence of other morphotypes, TC males may exhibit increased growth rates. Males and females used protein as an energy substrate. Males channeled approximately 9% of their energy budget into growth, whereas non-ovigerous and ovigerous females channeled only 1.4 ± 0.4 and 0.07 ± 0.07%, respectively. Whereas males and non-ovigerous females channeled 9.0 ± 9.74 and 61.8 ± 3.0%, respectively, of the energy ingested into metabolism, ovigerous females channeled 97.7 ± 4.7% into metabolism, likely due to the frequent beating of their pleopods, which oxygenates and cleans the eggs. As reported for marine prawns, males and non-ovigerous females of M. amazonicum lost approximately 5% of their ingested energy in exuviae. The physiological differences observed between the sexes and between females of different reproductive stages might reflect corresponding differences in patterns of activity, growth, and reproduction.

Reproductive biology of galatheoid and chirostyloid (Crustacea: Decapoda) squat lobsters from the Gulf of Mexico

Reproductive timing, fecundity, and average egg sizes were examined for galatheoid and chirostyloid squat lobster collections from the Gulf of Mexico. While congeners did not always significantly differ in egg size or timing, each genus had a unique average egg diameter size which may indicate whether the developing embryos will be lecithotrophic or planktotrophic larvae. The eggs of Eumunididae, Galatheidae, and Munididae were more numerous and smaller than the larger and less abundant eggs of Chirostylidae and Munidopsidae. With the exception of members of the Munididae, members of genera within the same family had distinct egg diameters. Ovigerous females were significantly larger than non-ovigerous females in some species (i.e., Uroptychus nitidus, Munida forceps, Galacantha spinosa, Munidopsis abbreviata, M. alaminos, M., erinacea, M. robusta, M. sigsbei, and M. simplex). Munidopsis erinacea and Munida affinis males were significantly larger than females; the reverse was true for Munidopsis robusta and Munidopsis simplex. All other species studied did not have a significant difference between males and females. The spatial and bathymetric ranges for many species are extended in this study from prior reports. Seasonality of reproduction was evident in few species, but this may be a result of limited sample sizes.