The family Potamotrygonidae are the only species of stingrays restricted to fresh water and located exclusively in South America. The objective of this research was to analyze the morphological ...aspects and germ cells of the male reproductive tract of Potamotrygon amandae. The samples were fixed in 10% formalin, and then dehydrated in an ascending ethanol series (70 to 100%). To carry out light microscopy analyses, they were embedded in paraffin, cut and stained; as for scanning electron microscopy analyses, the samples were dried, glued in metallic bases and metalized. The gross morphology consisted of the following paired organs: testis, epididymis, deferent duct, Leydig gland, seminal vesicle, clasper, and the clasper gland. Microscopically, several stages of spermatogenesis were observed in the testis, occurring in spherical follicles, similar to other stingrays. The epididymis was formed by one duct subdivided in various tubules. The deferent ducts were continuous with the epididymis, and the lumen was full of spermatozoa. The Leydig glands consisted of glandular units with eosinophilic content in the lumen of some, and the deferent ducts ran parallel to the ventral portion. The seminal vesicles possessed numerous compartments to store the sperm, with a wall similar to a hive, and the lumen was full of spermatozoa. Alcian Blue (AB) and Periodic Schiff-Acid (PAS) performed in the Leydig Gland, deferens ducts and seminal vesicle was positive only in the connective tissue, the cilia were PAS+ and the nuclei stained weakly for AB. The clasper gland was composed of unit glands and was covered with striated muscle externally. It stained very well with Periodic Schiff-Acid. The morphological aspects of the male reproductive tract of Potamotrygon amandae were similar to other stingrays.
Nawastuti D, Darwanto DH, Mulyo JH, Suadi. 2023. Consumer perceptions of stingrays in coastal areas of Indonesia. Biodiversitas 24: 6844-6851. Stingray populations harvested for food may pose risks ...to food security and conservation goals. The purpose of this research is (i) to determine the type of fish product based on how consumers obtain the product, (ii) to determine the gender of consumers based on the type of product, and (iii) ii) to determine the type of fish product for consumption purposes. Primary data were collected from Google Forms and followed by interviews with selected households. The number of respondents was 125 people from Java Island, Timor Island, Sumba Island, Adonara Island, Lembata Island, Bangka Belitung Island and Flores Island. The information obtained was investigated using Chi-square analysis to understand consumer preferences for fish consumption using an adaptation of SPSS 25 programming. The results of the research show that there are two relationships, namely (i) the type of fish product has a significant relation to fishing, the way consumers fish, the fishery products they buy and (ii) consumer gender has a significant relationship with product type because male consumers find it easier to get stingrays by fishing so they are easier to consume individually, in groups, or to sell. A proper understanding of gender differences in stingray consumption can help determine the sustainability of stingray fisheries in a region because it can be known exactly who can access sustainable food. Although there are several types of stingrays that are protected, other types of stingrays should not be consumed. The results we obtained can be useful for increasing public awareness regarding the use of fish catching and its impact on the carrying capacity of fisheries in Indonesia.
This study aimed to determine whether the long-term transport model of cururu stingray (Potamotrygon wallacei) could disturb the brain redox status and brain functions, including antioxidant ...defenses, signaling pathways activated by oxidative stress, and the physiological responses to transport-induced stress upon arrival and after its recovery; and also to identify how the addition of essential oil of Lippia alba (EOLA) in the water transport could influence on these changes. For this reason, the cururu stingrays were anesthetized with 200 mg/L eugenol and sampled by sectioning of the spinal cord before transport (n = 5), after 32 h-transport in the absence (n = 5) and presence of 10 μL/L of the EOLA (n = 5); and after recovery for 24 h and 48 h post-transport without and with EOLA (n = 5, each group) for blood and brain removal, totalizing 35 animals (four replicates). Transport triggered a rise in the levels of lactate in plasma and brain of cururu stingray on arrival. Besides, it increased the superoxide anion (O2•-) and hydrogen peroxide (H2O2) levels, and decreased the superoxide dismutase (SOD) 1 and 2, catalase, glutathione peroxidase (GPx) 1, and glutathione reductase (GR) activities, activated nuclear factor κB (NF-κB), led to glutathione oxidation, lipid peroxidation (measured through the thiobarbituric acid reactive substances (TBARS)), and elevated heat shock protein 70 (HSP70) levels in the cururu stingray brain. The addition of the EOLA to water protected brain against stress and oxidative stress on arrival, speeding up a process that could take until 48 h to occur in the absence of this additive. To reach this response, the EOLA decreased lactate levels in plasma and brain of cururu stingray, and also reduced O2•- and H2O2 levels, and NF-κB activation, increased SOD2, catalase, GPx1 and GR activities, decreased the ratio between oxidized and reduced glutathione, avoiding the increase in the TBARS levels in the brain tissue, and regulated the physiological responses to stress, as illustrated by low HSP70 levels found in it. These data make the addition of EOLA to the water even more recommended for long-term transport of cururu stingrays.
•Cururu stingray transport increases lactate in plasma and brain.•Transport triggers reactive oxygen species formation in brain.•The antioxidant defenses are deficient in the brain after transport.•Lippia alba essential oil decreases transport-induced oxidative stress.•Lippia alba regulates the physiological responses to stress.
Stingrays, including longheaded eagle ray(Aetobatus flagellum),have been the target of eradication activities as they are considered to prey on short-neck clams(Ruditapes philippinarum).However, ...stingrays play a critical role as a keystone species in tidal flat communities. To date, the assessment of stingray predation on short-neck clams has only been limited to laboratory experiments and gut content analyses. Therefore, to conserve both stingrays and short-neck clams, it is necessary to quantitatively evaluate the stingray predation on short-neck clams. In this study, we focused on the foraging pits made by stingrays on the Midorikawa River tidal flat in Ariake Bay, Kyushu, Japan. Moreover, we estimated the rate of stingray predation on short-neck clams and examined the magnitude of the effects of predation on the decline of short-neck clams using unmanned aerial vehicle and quantitative surveys. We found that the maximum rate of stingray predation on short-neck clams was 0.29% per day, which accounted for approximately 17.7% of the overall mortality rate of short-neck clams during the same month. Therefore, our findings suggest that stingray predation exerts only a limited effect on the decline of short-neck clam stocks in the study area.
Injuries from stingray fish are among the most common fish stings, and their frequency is increasing with the increase in global tourism. It most commonly causes injuries to the extremities and ...causes morbidity if not treated appropriately. Less commonly, life-threatening injuries can be observed due to injuries in the thorax and abdomen and damage to large vessels and vital organs. In addition to severe pain, tissue necrosis, and secondary infection after injury, systemic symptoms may occur. Since these injuries can occur in both fresh and salt water, it is possible to encounter such a case at any time. Flat spines are sharp, with backward barbs or serrations that make them difficult to extract once they penetrate tissue. After first aid, surgical extraction of the stingray spine with minimal damage is essential in addition to local and systemic treatments. In the literature, there are studies on envenomation and other systemic findings after stingray spine injuries, but few publications are available on the stingray spine extracted technique after injury. This case report presents a new and helpful technique for stingray spine extraction.
