Papers by Joycelyn Jumawan
DNA barcoding for accurate identification of invasive alien fish species is relatively unexplored... more DNA barcoding for accurate identification of invasive alien fish species is relatively unexplored. In this study, partial sequence (655 bp) of the mitochondrial gene COI (cytochrome c oxidase subunit I) was used to delineate between two species of exotic suckermouth sailfin catfish Pterygoplichthys – P. pardalis and P. disjunctivus and their intergrades, which dominate the ichthyofauna of the Marikina River system, Philippines. Individuals were assigned to groups using an abdominal pattern scheme, and COI gene sequence divergence analysis was determined using Kimura 2-parameter distances. Results revealed two major clusters which were inconsistent with the abdominal pattern categories and were characterized by low genetic divergence (mean 0.2%); one cluster having shared genealogy of individuals pre-identified as P. pardalis and the intergrades, and another consisting mostly of P. disjunctivus. From the samples, six haplotypes with low genetic divergence (mean 0.5%) were identified, suggesting that the haplotypes belong to a single species despite abdominal pattern variations. Overall, the DNA barcodes do not complement the morphology-based identification of the two species in the river system. The results support the possibility of introgressive hybridization between P. pardalis and P. disjunctivus and the need to reassess taxonomic assignment oft he two species using abdominal patterns as basis for species distinction. It is recommended that multiple molecular tools be used in future studies and that native Pterygoplichthys species and other hypostomine loricariids be subjected to DNA barcoding to fully classify this genus that deserves taxonomic attention.
EurAsian Journ al of BioSciences Eurasia J Biosci 8, 38-50 (2014) http://dx.doi.org/10.5053/ejobios.2014.8.0 .4
Abstract
Background: There is little information about the early development of this invasive fi... more Abstract
Background: There is little information about the early development of this invasive fish species in order to understand its early life history and developmental strategies towards invasion.
Material and Methods: Female Pterygoplichthys pardalis were induced to spawn using human chorionic gonadotropin (HCG) so as to study the developmental stages from fertilization until yolk
resorption.
Results: The females subjected to a single dose of HCG responded positively to treatment (97%) with higher fertilization success (88%) compared to the untreated females (21%). Nonetheless, the
HCG-induced fertilized eggs had a low hatching success (49%), while from the free-living embryos successfully hatched, a high number (90%) survived to become juveniles. Embryonic development in P. pardalis was completed 168 h and 30 min after fertilization, with the total yolk resorption completed on the 8
day post hatching, during which the suckermouth gradually shifted from rostral to ventral position to commence the loricariid algae-scraping feeding mode.
Conclusions: Pterygoplichthys pardalis does not undergo a true larval metamorphosis between the free-living embryo and the juvenile stage and a definitive adult phenotype is developed directly. These results provided basic, yet essential information on the early developmental features of this invasive species whose spawning and early developmental strategies were difficult to observe in the field. Implications of some ontogenetic features in this species with regards to invasion are also
discussed.
Keywords: Development, embryogenesis, invasion, larvae, morphology, Pterygoplichthys pardalis.
The ovarian histomorphology during the annual reproductive cycle of the non-native suckermouth sa... more The ovarian histomorphology during the annual reproductive cycle of the non-native suckermouth sailfin catfish, Pterygoplichthys disjunctivus (Weber 1991), a highly invasive and dominant fish population in Marikina River, Philippines was described from July 2010 to June 2011. Six ovary development stages were described with defined oocyte diameters in immature, maturing and spawning stages. Minimum length of maturity for females was at 26 cm standard length (SL), although incidences of precocious sexual maturity in several females as small as 19 cm SL were seen during the peak spawning months. Female P. disjunctivus have a relatively short spawning period (June to September) coinciding with the rainy season, followed by a short regression stage (October to December) which overlapped with the long recrudescent stage (October to early June). The three oocyte diameters in vitellogenic ovaries and the short spawning season suggest that the females were iteroparous batch spawners.
Lipid peroxidation and patterns of cadmium and lead accumulation in the gills, liver, gut and mus... more Lipid peroxidation and patterns of cadmium and lead accumulation in the gills, liver, gut and muscles of Pterygoplichthys Gill, 1858 from four stations in Marikina River,
Philippines were analyzed to study effects of possible metal toxicity alongside stress response. Mean cadmium (Cd) concentrations from tissues studied are within permissible amounts (0.02-0.05 mg L-1); mean lead (Pb) concentrations from themuscles, gills and gut were within permissible amounts except for the liver (0.22 mg L-1). Lipid peroxidation, indicative of oxidative stress was highest in the spleen, followed by
the liver and gills. Malondialdehyde (MDA) values were not correlated with lead and cadmium concentrations in fish samples and were not site- significant which suggest that
other possible factors might have also contributed to oxidative stress aside from lead and cadmium determined in the study. Histological observations of gills and gut show fair health for this invasive catfish, confirming several adjustments and adaptations towards air-breathing, although minute pathologic observations were seen in the liver. This study is the first to assess the patterns of heavy metal accumulation in this pollution-tolerant
fish under field conditions in relation to oxidative stress.
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Papers by Joycelyn Jumawan
Background: There is little information about the early development of this invasive fish species in order to understand its early life history and developmental strategies towards invasion.
Material and Methods: Female Pterygoplichthys pardalis were induced to spawn using human chorionic gonadotropin (HCG) so as to study the developmental stages from fertilization until yolk
resorption.
Results: The females subjected to a single dose of HCG responded positively to treatment (97%) with higher fertilization success (88%) compared to the untreated females (21%). Nonetheless, the
HCG-induced fertilized eggs had a low hatching success (49%), while from the free-living embryos successfully hatched, a high number (90%) survived to become juveniles. Embryonic development in P. pardalis was completed 168 h and 30 min after fertilization, with the total yolk resorption completed on the 8
day post hatching, during which the suckermouth gradually shifted from rostral to ventral position to commence the loricariid algae-scraping feeding mode.
Conclusions: Pterygoplichthys pardalis does not undergo a true larval metamorphosis between the free-living embryo and the juvenile stage and a definitive adult phenotype is developed directly. These results provided basic, yet essential information on the early developmental features of this invasive species whose spawning and early developmental strategies were difficult to observe in the field. Implications of some ontogenetic features in this species with regards to invasion are also
discussed.
Keywords: Development, embryogenesis, invasion, larvae, morphology, Pterygoplichthys pardalis.
Philippines were analyzed to study effects of possible metal toxicity alongside stress response. Mean cadmium (Cd) concentrations from tissues studied are within permissible amounts (0.02-0.05 mg L-1); mean lead (Pb) concentrations from themuscles, gills and gut were within permissible amounts except for the liver (0.22 mg L-1). Lipid peroxidation, indicative of oxidative stress was highest in the spleen, followed by
the liver and gills. Malondialdehyde (MDA) values were not correlated with lead and cadmium concentrations in fish samples and were not site- significant which suggest that
other possible factors might have also contributed to oxidative stress aside from lead and cadmium determined in the study. Histological observations of gills and gut show fair health for this invasive catfish, confirming several adjustments and adaptations towards air-breathing, although minute pathologic observations were seen in the liver. This study is the first to assess the patterns of heavy metal accumulation in this pollution-tolerant
fish under field conditions in relation to oxidative stress.
Background: There is little information about the early development of this invasive fish species in order to understand its early life history and developmental strategies towards invasion.
Material and Methods: Female Pterygoplichthys pardalis were induced to spawn using human chorionic gonadotropin (HCG) so as to study the developmental stages from fertilization until yolk
resorption.
Results: The females subjected to a single dose of HCG responded positively to treatment (97%) with higher fertilization success (88%) compared to the untreated females (21%). Nonetheless, the
HCG-induced fertilized eggs had a low hatching success (49%), while from the free-living embryos successfully hatched, a high number (90%) survived to become juveniles. Embryonic development in P. pardalis was completed 168 h and 30 min after fertilization, with the total yolk resorption completed on the 8
day post hatching, during which the suckermouth gradually shifted from rostral to ventral position to commence the loricariid algae-scraping feeding mode.
Conclusions: Pterygoplichthys pardalis does not undergo a true larval metamorphosis between the free-living embryo and the juvenile stage and a definitive adult phenotype is developed directly. These results provided basic, yet essential information on the early developmental features of this invasive species whose spawning and early developmental strategies were difficult to observe in the field. Implications of some ontogenetic features in this species with regards to invasion are also
discussed.
Keywords: Development, embryogenesis, invasion, larvae, morphology, Pterygoplichthys pardalis.
Philippines were analyzed to study effects of possible metal toxicity alongside stress response. Mean cadmium (Cd) concentrations from tissues studied are within permissible amounts (0.02-0.05 mg L-1); mean lead (Pb) concentrations from themuscles, gills and gut were within permissible amounts except for the liver (0.22 mg L-1). Lipid peroxidation, indicative of oxidative stress was highest in the spleen, followed by
the liver and gills. Malondialdehyde (MDA) values were not correlated with lead and cadmium concentrations in fish samples and were not site- significant which suggest that
other possible factors might have also contributed to oxidative stress aside from lead and cadmium determined in the study. Histological observations of gills and gut show fair health for this invasive catfish, confirming several adjustments and adaptations towards air-breathing, although minute pathologic observations were seen in the liver. This study is the first to assess the patterns of heavy metal accumulation in this pollution-tolerant
fish under field conditions in relation to oxidative stress.