Pomacea Paludosa Research Articles

Freshwater snail flesh (Pomacea paludosa) incubated with bromelain enzyme levels in feed on the carcass quality of Alabio male ducks (Anas plathyrhyncos Borneo)

This study aimed to determine Freshwater snail flesh (Pomacea paludosa) incubated with bromelain enzyme levels in feed on the carcass quality of alabio male ducks. The treatment as ; P0 basal diet + 100% fish meal, P1 basal diet + 75% fish meal + 25% freswater snail flesh incubated bromelain enzym, P2 basal diet + 50% fish meal + 50% freswater snail flesh incubated bromelain enzym, P3 : basal diet + 25 % fish meal + 75% freswater snail flesh incubated bromelain enzym, P4 : basal diet + 100% freswater snail flesh . In each treatment, two male Alabio ducks were taken randomly and then slaughtered. The crude protein, crude fat, moisture, pH, and texture, by taking as many samples as 20 g of sample then mashed for 2 minutes and added 40 ml aquadest. pH measurement is done with pH meter, which was previously calibrated with buffer solution of pH 7.0 and 4.0. Meat tenderness is measured by using the shear warner bratzler tool Instron, , protein,fat and moiture using proximate analysis The result showed that level freshwater snail flesh incubated with bromelain enzym in feed up to 7.5-10% on Alabio male duck diets improved crude protein meat (21.51±0.19 to 23.90±0.40) but decreased meat moisture ( 69.46±0.79 to 62.79±0.27) and decreased crude fat meat (9.55±0.44 to 4.18±0.53). Meanwhile, the tenderness of the meat increased from 3.55% on the control feed to 26.77% on the feed using 7.5-10%.

Correlation of Macrozoobenthos Diversity Index with Physico-Chemical Factors in Lake Toba, Toba Samosir Regency

This study aims to determine the macrozoobenthos in Lake Toba, Toba Samosir Regency. This research was conducted from May to July 2018. Determination of research stations based on environmental baseline consisted of 4 stations, namely station 1 in Lumban Binanga Laguboti village, station 2 in Lumban Bul-bul Balige, station 3 in Lumban Binanga Sigumpar, and station 4 in Hutagaol Sigumpar. Samples were taken using Eckman Grab at 3 times at each station. The macrozoobenthos found consisted of two classes, three orders, eight families, 15 species with a total of 565 individuals. The species found were Brotia subgloriosa, Brotia peninsularis, Brotia castulata, Pomacea diffusa, Pomacea paludosa, Filopaludina polygramma, Filopaludina sp., Melanoides tuberculata, Lymnaea sp., Emilia sp., Corbicula sumatrana, Corbicula fluminea, Corbicula japonica, Pilsbryoconcha exilis, and Anodonta sp.. The macrozoobenthic species with the highest number of individuals was Corbicula sumatrana with 141 individuals and the least was Lymnea sp. by 1 individual. The macrozoobenthos ecological analysis included the average density of 2260, the average diversity index of 1.282, the average uniformity index of 0.633, and the average dominance of 0.390. Then correlated with physico-chemical factors using Pearson correlation (r). Correlation of diversity index with physico-chemical factors from the strongest to the weakest starting from depth and phosphate, turbidity, temperature, pH, BOD, and DO.

Evaluation in Alabio duck (Anas plathyrhincos Borneo) of soluble protein, protein digestibility, metabolizable energy and nitrogen retention of freshwater snail flesh (Pomacea paludosa) incubated with bromelain enzyme for different times and concentrations

Evaluation in Alabio duck (Anas plathyrhincos Borneo) of soluble protein, protein digestibility, metabolizable energy and nitrogen retention of freshwater snail flesh (Pomacea paludosa) incubated with bromelain enzyme for different times and concentrations

Effects of the Replacing of Fish Meal with Freshwater Snail Flesh (Pomacea paludosa) Treated with Bromelain Enzyme on Growth Performance, Relatively Organ Weight, and Digestibility of Alabio Ducks (Anas plathyrhyncos Borneo)

This study aimed to determine the effects of the replacing of fish meal with freshwater snail flesh (

Quantifying edge effects on apple snails (Pomacea paludosa) and their eggs at the junction of two wetland habitat types

Quantifying edge effects on apple snails (Pomacea paludosa) and their eggs at the junction of two wetland habitat types

Life history traits determine the differential vulnerability of native and invasive apple snails (Pomacea spp.) to a shared juvenile-stage predator

The vulnerability of gastropods to their predators varies with life history traits such as morphology, body size, behavior, and growth rates as well as predator size. A recent study suggested that the invasive apple snail, Pomacea maculata, was considerably more vulnerable to crayfish predators than the native Florida apple snail, P. paludosa. The difference was hypothesized to be caused by the relatively small hatchling size of P. maculata. To test this hypothesis, we conducted a series of feeding assays designed to quantify maximum feeding rates and selective foraging of crayfish on apple snails. The rate at which crayfish killed individual P. maculata (i.e., kill rates) decreased with snail size, and kill rates on both species increased with crayfish size. Kill rates on juvenile P. maculata were higher than kill rates on size-matched hatchling P. paludosa, and crayfish fed selectively on P. maculata when offered mixed groups of size-matched snails. Further analyses revealed that hatchling P. paludosa possess shells 1.8× heavier than size-matched P. maculata suggesting differences in vulnerability to crayfish were consistent with interspecific differences in shell defenses. Differences in hatchling size and defensive traits in combination make crayfish kill rates on hatchling P. maculata approximately 15.4× faster than on hatchling P. paludosa, but the relative contribution of hatchling size to differences in apple snail vulnerability was >3× greater than the contribution of defensive traits.

Effects of the Consumption Behavior of AdultPomacea maculataandPomacea paludosaonVallisneria americana

Abstract Understanding differences in behavioral characteristics between invasive non-native species and native species is an important step in preventing, managing, and mitigating environmental impacts. This study examined the differences between adult life-stage native Pomacea paludosa (Florida Applesnail) and adult non-native Pomacea maculata (Giant Applesnail) grazing behavior and rates on Vallisneria americana (Tapegrass), a plant of restoration importance, to assess the potential ecological impact. We used an experimental design with entire intact specimens of Tapegrass placed in 8 tanks of each of 3 treatment groups: (1) grazed by Giant Applesnail, (2) grazed by Florida Applesnail, and (3) control with no snails. Rates of herbivory on, and physical and total biomass damage to, Tapegrass by Giant Applesnail were 1.8 cm/hr, 2.5cm/hr, and 4.2 cm/hr, respectively. Rates of herbivory on, and physical and total biomass damage to, Tapegrass by Florida Applesnail were 0.2 cm/hr, 1.2 cm/hr, and 1.4 cm/hr, r...

Types of Ampullariidae (Mollusca: Gastropoda) in the Academy of Natural Sciences of Philadelphia

The Ampullariidae Gray, 1824 constitute a family of freshwater caenogastropods predominantly distributed in humid tropical and subtropical habitats in Africa, South and Central America and Asia. They include the largest of all freshwater snails and frequently comprise a major portion of the native freshwater mollusc faunas of these regions. Ampullariid taxonomy is confused, primarily because most species were described on the basis of shell morphology alone, which is highly variable within species yet relatively conservative among species within the family. The need for rigorous taxonomic treatment of the group is acute and the basis for such research is comprehensive study of type material. With type or possible type material of 31 nominal species-group taxa of Ampullariidae, belonging to the genera Felipponea Dall, 1919 (1 taxon, South America), Lanistes Montfort, 1810 (6 taxa, Africa), Marisa Gray, 1824 (1, South America), Pila Roding, 1798 (1, Asia; 4 Africa), and Pomacea Perry, 1810 (17, South, Central, North America), as well as 1 incertae sedis taxon in New World Ampullariidae, the Academy of Natural Sciences has significant holdings, for which this annotated catalogue is provided. Information in each account includes original name and combination, citation to the original description, current taxonomic status, type material held by the Academy of Natural Sciences (holotypes, a neotype, paratypes, lectotypes, paralectotypes) with catalogue number(s) and number of specimens in each catalogue lot, type locality, collectors and dates of collection, and other remarks or additional information as appropriate. A lectotype is designated for Ampullaria pealiana Lea, 1838, and a neotype is designated for Pomacea paludosa flava Smith, 1937. All name-bearing types are illustrated.

Native crayfish consume more non-native than native apple snails

Recent studies suggest native aquatic predators can favor native over invasive species and provide biotic resistance to invasions. The invasive apple snail, Pomacea maculata continues to spread in freshwaters of Florida and appears to be a strong competitor of the native Florida apple snail (P. paludosa). Little is known about effects of predators on either species and we compared the effects of a common native crayfish predator (Procambarus fallax) on hatchlings and juveniles. Because crayfish feed size-selectively, we predicted that the smaller P. maculata hatchlings would be more vulnerable than the hatchlings of native P. paludosa. In experimental wetland mesocosms, crayfish reduced survival of both species, but none of the P. maculata survived the 44 days exposure, such that predatory effects of crayfish were >8× stronger on the non-native P. maculata than on native P. paludosa. Crayfish in the lab selectively consumed the smaller P. maculata when offered both hatchlings simultaneously. We combined the observed survival rates with published life history data and the results (i.e., projected survivors clutch−1) suggested that wetlands with crayfish could have greater limiting effects on non-native P. maculata than the native P. paludosa. Wetland conditions favoring populations of native crayfish may also favor the relatively predator-resistant native P. paludosa.

Modeling apple snail population dynamics on the Everglades landscape

The Florida Everglades has diminished in size and its existing wetland hydrology has been altered. The endangered snail kite (Rostrhamus sociabilis) has nearly abandoned the Everglades, and its prey, the apple snail (Pomacea paludosa), has declined. We developed a population model (EverSnail) to understand apple snail response to inter- and intra-annual fluctuations in water depths over the Everglades landscape. EverSnail was developed as a tool to understand how apple snails respond to different hydrologic scenarios. EverSnail is an age- and size-structured, spatially-explicit landscape model of P. paludosa in the Everglades. Landscape-level inputs are water depth and air temperature. We conducted sensitivity analyses by running EverSnail with ±20 % the baseline value of eight parameters. EverSnail was sensitive to changes in survival and water depth associated with reproduction. The EverSnail population varied with changes and/or differences in depth generally consistent with empirical data; site-specific comparisons to field data proved less reliable. A simulated 3-year wet period resulted in a shift in apple snail distribution, but little change in total abundance over the landscape. In contrast, a simulated 3-year succession of relatively dry years resulted in overall lower snail abundances. Comparisons of model output to empirical data indicate the need for more data to better understand, and eventually parameterize, several aspects of snail ecology in support of EverSnail. A primary value of EverSnail is its capacity to describe the relative response of snail abundance to alternative hydrologic scenarios considered for Everglades water management and restoration.

Influence of water quality on zinc toxicity to the Florida apple snail (Pomacea paludosa) and sensitivity of freshwater snails to zinc.

The present study characterized the influence of water-quality characteristics on zinc (Zn) toxicity to the Florida apple snail (Pomacea paludosa) and the sensitivity of freshwater snails to Zn. Standard 96-h renewal acute toxicity tests were conducted with Zn and juvenile P. paludosa under 3 conditions of pH and alkalinity, water hardness, and dissolved organic carbon (DOC). Median lethal effect concentrations (96-h LC50s), no-observed- effect concentrations, lowest-observed-effect concentrations, LC10s, and LC20s were determined for each test. The results showed that Zn toxicity to P. paludosa decreased linearly with increasing hardness, pH, and DOC. A multiple linear regression model based on pH, hardness, and DOC was able to explain 99% of the observed variability in LC50s. These results are useful for the development of a biotic ligand model (BLM) for P. paludosa and Zn. Zinc acute toxicity data were collected from the literature for 12 freshwater snail species in a wide range of water-quality characteristics for species sensitivity distribution analysis. The results showed that P. paludosa is the second most sensitive to Zn. The present study also suggested that aqueous ZnCO3 and ZnHCO3 (-) can be bioavailable to P. paludosa. Therefore, bioavailability models (e.g., BLM) should take these Zn species into consideration for bioavailability when applied to snails.

Dispatches

Dispatches

Reproductive responses of the endangered snail kite to variations in prey density

ABSTRACTUnderstanding how predators respond to fluctuations in prey density has important conservation and management implications, particularly for threatened and endangered specialists. However, directly linking prey densities to predator behavior and demography over broad spatial and temporal scales is rare, in part, because it can be prohibitively expensive and time‐consuming to quantify prey density over large areas. We link nesting data collected by a long‐term monitoring program for the endangered snail kite (Rostrhamus sociabilis plumbeus) with 44 density estimates of its primary prey, the Florida apple snail (Pomacea paludosa), collected by multiple, smaller‐scale studies from 2002 to 2010. We found evidence that key components of kite breeding biology—nest density and the number of young fledged per successful nest—were positively related to snail density. Although previous studies have shown that densities greater than approximately 0.1–0.2 snails/m2 may be necessary to sustain profitable foraging and that capture times for individual foraging kites begin to level off as snail densities exceed approximately 0.4 snails/m2, we found continued numerical responses in snail kite reproductive parameters at greater snail densities. At occupied sites (i.e., snail‐sampling sites in which ≥1 snail kite nest was present within a 2‐km radius during the primary sampling period: Mar–May), the average snail density was 0.45 snails/m2 (SE = 0.12, n = 17), whereas that of unoccupied sites was 0.12 snails/m2 (SE = 0.02, n = 27). Along the snail density gradient from 0.2 to 0.4 to 1.2 snails/m2, model predictions indicated that 1) the probability of site occupancy (by nesting kites) increased from 0.48 to 0.69 to 0.90, 2) local nest abundance of occupied sites increased from 4 to 7 to 16 nests, and 3) the probability of a successful nesting attempt fledging more than 1 young increased from 0.02 to 0.07 to 0.43. We found no evidence of a snail density effect on nest survival. Understanding the differential effects of snail density on various components of snail kite breeding biology is essential to the development and implementation of management tools used for snail kite conservation and Everglades restoration. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Effects of a non-native cichlid fish (African jewelfish, Hemichromis letourneuxi Sauvage 1880) on a simulated Everglades aquatic community

In an 8-month mesocosm experiment, we examined how a simulated Everglades aquatic community of small native fishes, snails, and shrimp changed with the addition of either a native predator (dollar sunfish Lepomis marginatus) or a non-native predator (African jewelfish Hemichromis letourneuxi) compared to a no-predator control. Two snail species (Planorbella duryi, Physella cubensis) and the shrimp (Palaemonetes paludosus) displayed the strongest predator-treatment effects, with significantly lower biomasses in tanks with Hemichromis. One small native fish (Heterandria formosa) was significantly less abundant in Hemichromis tanks, but there were no significant treatment effects for Gambusia holbrooki, Jordanella floridae, or Pomacea paludosa (applesnail). Overall, there were few treatment differences between native predator and no-predator control tanks. The results suggest that the potential of Hemichromis to affect basal food-web species that link primary producers with higher-level consumers in the aquatic food web, with unknown consequences for Florida waters.

The presence of an exotic snail, Pomacea maculata, inhibits growth of juvenile Florida apple snails, Pomacea paludosa

The presence of an exotic snail, Pomacea maculata, inhibits growth of juvenile Florida apple snails, Pomacea paludosa

The Effects of Prey Density on Capture Times and Foraging Success of Course-Hunting Adult Snail Kites

Abstract. Foraging-patch selection may be influenced by prey density, prey availability, and the energetic costs associated with searching for and capturing prey. Although prey density influences profitability, prey availability may be influenced by habitat and environmental characteristics. We made in situ observations of Snail Kites (Rostrhamus sociabilis) foraging on their exclusive prey, apple snails (Pomacea paludosa), in selected habitats and environmental conditions. We measured the time to capture a snail at 10 sites on Florida lakes (two sites sampled twice over different years for 12 data points total) and five sites in wetlands of the Everglades. Capture times had an inverse asymptotic relationship to snail density. As snail density increased from ∼0.1 to 0.2m-2, capture times declined from ∼600 to 200 sec; capture times leveled off to ∼75 sec between 0.4 and 1.4 snails m-2. Densities of emergent plant stems and water depths, which may influence capture times, were controlled for by site select...

Development of a captive breeding program for the Florida apple snail, Pomacea paludosa: Relaxation and sex ratio recommendations

Stock enhancement of the Florida apple snail, Pomacea paludosa, is a potential management strategy for the conservation of the endangered snail kite which is dependent upon the snail as its predominant food source. Reliable culture techniques that provide high growth and survival rates for juvenile snails have been established; however, additional research is needed to improve breeding in captivity. The goals of this study were to efficiently relax the snails to identify the sex in order to conduct a study to understand the effect of different sex ratios on reproductive output. Of the seven chemical solutions used to relax the snails, benzocaine mixed in methanol was the most effective. To examine the effect of sex ratio, 10 snails were stocked into 75L tanks within a recirculating aquaculture system at the ratios of 3F:7M, 5F:5M, 7F:3M, and 8F:2M for 8weeks. There was a significant positive relationship between the number of egg clutches produced and a higher number of females in the tank. However, there were no significant differences in the number of eggs per clutch, egg diameter, percent hatch rates, female production (egg clutches per female per week), or the number of juvenile snails produced per female. The number of copulations was observed for the first three weeks of the experiment. When standardized to the number of copulations per male snails, no significant differences between treatments were detected. Our results suggest that a female-biased sex ratio may prove optimal and cost effective for large-scale captive breeding production. Future studies should determine the minimal proportion of males needed to limit the loss of genetic diversity in a female-biased stock enhancement program.

The effect of stocking density on the reproductive output of hatchery-reared Florida apple snails, Pomacea paludosa

The effect of stocking density on the reproductive output of Florida apple snails was investigated with the goal of developing a captive breeding program that would sustain year-round production and yield a high number of juvenile snails. We examined stocking densities of 50, 100, and 150 snails/m2 to determine the threshold at which density negatively affects reproduction. Adult snails were added to tanks in a recirculating aquaculture system at a 1:1 sex ratio and reproductive output was followed for 8weeks. The total number of clutches per tank and the number of eggs per clutch were recorded daily. The number of egg clutches produced in each tank was standardized per female to assess among treatment differences. Once hatched, the juveniles were counted and the percent hatch rates were determined for each clutch. The findings of the study demonstrated that density affected the mean number of clutches laid per female per week with snails in the 50 snails/m2 treatment having higher egg production than snails stocked at 100 and 150 snails/m2 treatments. Similarly, the number of juveniles produced per female was also higher in the lowest density treatment. There were no significant differences between treatments for egg characteristics (number of eggs per clutch and percent hatch rate). Based on these results, it is recommended that adult snails be stocked at 50 snails/m2 to yield optimum egg production per female, attain the highest number of juveniles, and to sustain production for a reliable captive breeding program.

An Artificial Perch to Help Snail Kites Handle an Exotic Apple Snail

In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.

Bioaccumulation and toxicity of copper in outdoor freshwater microcosms

This study characterizes the effects of copper (Cu) on Florida apple snails ( Pomacea paludosa) and mosquito fish ( Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m 3 fiberglass microcosm tanks. Introducing juvenile apple snails (≤7 d old) and mosquito fish (2–3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 μg/L, respectively and decreased to low saturation levels of about ≤9 μg/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model ( L ∞) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g. Growth rate ( k) of the snails increased in order of shell height (0.459), shell length (0.550), and shell weight (0.598). There was no reproduction in the snails in any treatments including the reference during the exposure phase. However, Cu did not affect reproduction of fish during this period. Copper concentrations in periphyton from Equus, SRB, and AGLR microcosms ranged from 2 to 62, 31 to 371, and 13 to 478 mg/kg, respectively. Copper concentrations in fish at the beginning, days 30 and 150 of the study ranged from 3.19 to 7.53 mg/kg and were not significantly different from the different treatments. Average Cu concentrations in the soft tissue of dead snails from SRB and AGLR microcosms were 4602 mg/kg dw (ranged from 2913 to 8370 mg/kg dw) and 2824 mg/kg dw (ranged from 2118 to 3600 mg/kg dw), respectively. The Cu concentrations in the soft tissue of dead snails found in this study were higher than the tissue Cu concentrations in live aquatic organisms reported in the literature. These high Cu concentrations in edible apple snail soft tissue might pose a risk to Florida apple snail predators, including the snail kite. The post-exposure phase, with snails exposed to only water (i.e., no soils) showed depuration of copper from apple snails and reproduction in all treatments.