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Qiang Lin - One of the best experts on this subject based on the ideXlab platform.
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kinematics of prey capture and histological development of related organs in juvenile Seahorse
Aquaculture, 2021Co-Authors: Bo Zhang, Jinhui Sun, Shangduan Xie, Honghao Zhao, Yanjing Yang, Pei Cui, Sudong Xia, Qiang LinAbstract:Abstract The Seahorse is a typical suction feeder with an elongated, tubular snout and a small terminal mouth. It is important to determine the details of this unique prey-capture behavior to improve the survival rate during Seahorse breeding, especially for juveniles. In this study, we described the sucking process and characterized the kinematics in juvenile lined Seahorse (Hippocampus erectus) at different ages (1–30 days after parturition; DAP) using a high-speed video system, and also investigated the histological basis of the feeding-related organs, including snout, eye, and intestine. The sucking of juvenile Seahorses can be divided into four steps: searching, locating, capturing, and swallowing. Seahorses capture prey mainly based on the vision system, and histological results revealed a developed visual acuity in the newborn Seahorses, so that they were able to prey once after releasing from the male Seahorse's brood pouch. The attack distance, maximum snout width, capture success rate, and daily food intake of juvenile Seahorses increased with maturation. A remarkable inflection point, in the snout expansion rate, successful predation rate, and growth rate, occurs at about 10 DAP, when calcification of the snout bones was completed. In addition, the intestines of newborn Seahorses were short and quite simple, but developed rapidly during the first 20 DAP. These findings provide a better understanding of prey capture kinematics and nutritional physiology, and will be beneficial for improving the feeding strategies for juveniles during large Seahorse breeding.
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effects of chronic exposure to environmental levels of tributyltin on the lined Seahorse hippocampus erectus liver analysis of bioaccumulation antioxidant defense and immune gene expression
Science of The Total Environment, 2021Co-Authors: Lu Tang, Geng Qin, Yanhong Zhang, Xin Wang, Canchuan Zhang, Qiang LinAbstract:Tributyltin (TBT), an organotin compound frequently detected in the coastal environments, poses a threat to aquatic organisms. The lined Seahorse (Hippocampus erectus) is a vulnerable species found in nearshore water habitats. The mechanisms by which this fish responds to TBT exposure are not yet fully understood. Histological, biochemical, and transcriptional analyses were conducted, and the results showed that 60 days of exposure to 50 and 500 ng/L TBT caused significant tin accumulation and liver damage to Seahorses. Antioxidant defenses and immune responses to TBT exposure in the livers of Seahorses were further investigated. The enzymatic activity of superoxide dismutase and malondialdehyde content increased, while catalase activity decreased. Transcriptomic analysis revealed that a series of genes involved in the antioxidant defense system were highly induced to protect the hepatic cells from oxidative damage. TBT exposure also resulted in the induction of genes associated with immune and inflammatory processes, representing a stress response to combat the adverse environmental conditions in the exposed Seahorses. Furthermore, Seahorses showed an increased health risk, according to the elevation of the expression of genes with tumor-promoting effects, when exposed to TBT. These findings contribute to our understanding of the adverse effects of TBT exposure on Seahorses, and their potential defense mechanisms.
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wnt8a is one of the candidate genes that play essential roles in the elongation of the Seahorse prehensile tail
Marine Life Science & Technology, 2021Co-Authors: Bo Zhang, Geng Qin, Yanhong Zhang, Chunlei Cang, Qiang LinAbstract:Seahorses are a hallmark of specialized morphological features due to their elongated prehensile tail. However, the underlying genomic grounds of Seahorse tail development remain elusive. Herein, we evaluated the roles of essential genes from the Wnt gene family for the tail developmental process in the lined Seahorse (Hippocampus erectus). Comparative genomic analysis revealed that the Wnt gene family is conserved in Seahorses. The expression profiles and in situ hybridization suggested that Wnt5a, Wnt8a, and Wnt11 may participate in Seahorse tail development. Like in other teleosts, Wnt5a and Wnt11 were found to regulate the development of the tail axial mesoderm and tail somitic mesoderm, respectively. However, a significantly extended expression period of Wnt8a during Seahorse tail development was observed. Signaling pathway analysis further showed that Wnt8a up-regulated the expression of the tail axial mesoderm gene (Shh), while interaction analysis indicated that Wnt8a could promote the expression of Wnt11. In summary, our results indicate that the special extended expression period of Wnt8a might promote caudal tail axis formation, which contributes to the formation of the elongated tail of the Seahorse.
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genome wide evolution of mapks family and their expression in response to bacterial infection in Seahorse hippocampus erectus
Journal of Oceanology and Limnology, 2021Co-Authors: Kai Wang, Xin Wang, Qiang Zou, Han Jiang, Rongrong Zhang, Yanan Tian, Lele Zhang, Qiang LinAbstract:Seahorses have evolved many unique biological traits, including a male brood pouch, the absence of caudal and pelvic fins, and the lack of spleen and gut-associated lymphatic tissue. The mitogen-activated protein kinases (MAPKs) are known to be involved in various important biological processes including growth, differentiation, immunity, and stress responses. Therefore, we hypothesized that the adaptive evolution and expression of the MAPK gene family in Seahorse may differ from those of other teleost species. We identified positive selection sites in the erk2, erk5, jnk1, and p38α MAPK genes of the lined Seahorse Hippocampus erectus and tiger-tailed Seahorse Hippocampus comes. A novel expression profile of MAPK cascade genes was found in Seahorse larvae during the first day after birth based on the RNA-seq data of H. erectus, which reflected vital signs of immune response to its parental immune system. The expression patterns of the four positively selected MAPK genes were analyzed following the bacterial challenge of Vibrio fortis, revealing their upregulation pattern in brood pouch and other immune tissues. This study enriched our knowledge of the evolution of the H. erectus MAPK subfamilies, and could help better understanding the functional role of MAPKs in teleosts.
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effects of tributyltin on gonad and brood pouch development of male pregnant lined Seahorse hippocampus erectus at environmentally relevant concentrations
Journal of Hazardous Materials, 2021Co-Authors: Lu Tang, Geng Qin, Qiang Lin, Yali Liu, Yanhong ZhangAbstract:The male pregnancy of Seahorses is unique, but their reproductive response to environmental disturbances has not yet been clarified. Tributyltin (TBT) is known to have an endocrine disrupting effect on the reproductive system of coastal marine organisms. This study evaluated the potential effects of exposure to environmentally relevant concentrations of TBT on the development of gonads and brood pouch of the lined Seahorse (Hippocampus erectus). Physiological, histological, and transcriptional analyses were conducted, and results showed that high levels of TBT bioaccumulation occurred in male and female Seahorses. TBT led to ovarian follicular atresia and apoptosis with the elevation of androgen levels, accompanied by the induction of genes associated with lysosomes and autophagosomes. Comparative transcriptional analyses revealed the likely inhibition of spermatogenesis via the suppression of cyclic AMP and androgen synthesis. Notably, the transcriptional profiles showed that TBT potentially affects the immune system, angiogenesis, and embryo nourishment of the brood pouch, which indicates that it has negative effects on the male reproductive system of Seahorses. In summary, this study reveals that environmental levels of TBT potentially affect the reproductive efficiency of Seahorses, and may ultimately lead to a reduction in their populations in coastal environments.
Keith M Martinsmith - One of the best experts on this subject based on the ideXlab platform.
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genetic monogamy despite social promiscuity in the pot bellied Seahorse hippocampus abdominalis
Molecular Ecology, 2007Co-Authors: Anthony B Wilson, Keith M MartinsmithAbstract:Sexual selection theory predicts a positive correlation between relative parental investment and mate choice. In syngnathid fishes (Seahorses and pipefish), males brood offspring in specialized brooding structures. While female-female mating competition has been demonstrated in some pipefishes, all Seahorses (genus Hippocampus) studied to date have been found to have conventional sex roles with greater male-male competition for access to mates despite possessing the most complex brood structures in the family. Although multiple mating is common in pipefish, Seahorses are again exceptional, exhibiting strict genetic monogamy. Both demographic and behavioural explanations have been offered to explain the lack of multiple mating in Seahorse species, but these hypotheses have not yet been explicitly addressed. We investigated mating systems and brood parentage of the pot-bellied Seahorse, Hippocampus abdominalis, a temperate-water species that is socially promiscuous with conventional sex roles in laboratory populations. We observed promiscuous courtship behaviour and sex-role reversal in high density, female-biased field populations of H. abdominalis. We hypothesize that sex roles are plastic in H. abdominalis, depending on local population density and sex ratio. Despite promiscuous courtship behaviour, all assayed male Seahorses were genetically monogamous in both laboratory and wild populations. Physiological limitations associated with embryo incubation may explain the absence of multiple mating in Seahorses and may have played an important role in the development of the unique reproductive behaviour typical in these species.
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Seahorse declines in the derwent estuary tasmania in the absence of fishing pressure
Biological Conservation, 2005Co-Authors: Amanda C J Vincent, Keith M MartinsmithAbstract:Abstract Seahorses have the potential to be flagship species for estuarine conservation around the world and considerable concern has arisen over their declining abundance in the face of exploitation. All Seahorses were recently listed on CITES Appendix II in recognition of threats posed by unsustainable trade. However, the efficacy of this measure and the development of other effective conservation solutions will require an understanding of natural Seahorse population dynamics at relevant ecological scales. In this study, we provide quantitative data on Seahorse populations over nested spatial and temporal scales up to 10 km and 3.5 years. Unexploited populations of the big-bellied Seahorse (Hippocampus abdominalis) in the Derwent estuary, Tasmania, Australia consisted largely of mature adults with highly female-biased sex ratios at all sites. While big-bellied Seahorses had an aggregated distribution at the spatial scale of our transects (200 m2), most individuals were found alone. When they occurred in groups, the distribution of individuals was random with respect to sex in contrast to the pair bonds found in other Seahorse species. All three monitored populations showed significant declines in abundance of 79–98% over the period 2001–2004. Estuarine physicochemical conditions did not change markedly during this period. Possible causes of Seahorse declines are interactions with invasive species, disease or reproductive limitation through Allee effects. The magnitude of the declines in the absence of direct exploitation demonstrates that Seahorses face multiple threats. Robust fisheries-independent monitoring will be required to demonstrate that conservation actions such as CITES listing are effective.
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visible implant fluorescent elastomer tagging of the big bellied Seahorse hippocampus abdominalis
Fisheries Research, 2004Co-Authors: Chris M C Woods, Keith M MartinsmithAbstract:Abstract Wild and captive management of Seahorses often requires individual or batch identification. In Seahorses this has proven difficult in the past because of the Seahorses’ rigid body structure, reduced size of fins and susceptibility to infection. We investigated the suitability of visible implant fluorescent elastomer (VIFE) for tagging the big-bellied Seahorse, Hippocampus abdominalis, Leeson 1827. Thirty-six Seahorses were tagged and their mortality, growth and tag retention assessed over a period of 7 months together with 36 control Seahorses. No tagged or control animal died. In tagged animals growth rate in standard length (SL) was 6% less than untagged animals (non-significant), and growth rate in weight was 10% less than untagged animals (significant) over the experimental period. No tags were lost during the experiment. Tag visibility under LED blue light did not decline significantly although tag detection with the naked eye decreased significantly over the first month of the experiment. Our results show that VIFE is a highly effective batch tagging method for Seahorses with minimal biological effects.
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collaborative development of management options for an artisanal fishery for Seahorses in the central philippines
Ocean & Coastal Management, 2004Co-Authors: Amanda C J Vincent, Jessica J Meeuwig, Keith M Martinsmith, Melita SamoilysAbstract:Overexploitation and habitat degradation threaten small-scale, artisanal fisheries around the world. Management of these fisheries is often inadequate or absent, partly because they are data poor. We here present the development of management options for such a fishery, using collaborative input from a variety of interested groups. Qualitative and semi-quantitative assessments of Seahorse populations in central Philippines suggest that they are overfished. Management objectives focus on rebuilding Seahorse stocks, maintaining income for fishers and ensuring long-term persistence of Seahorse populations. We developed a list of 11 management options at a workshop of fisheries experts from a variety of backgrounds. We then undertook an iterative process of consultation involving fishers, traders, consumers, conservationists, aquarists, national and international policy groups. The creation of no-take Marine Protected Areas and minimum size limits for Seahorses were strongly supported by all groups, emerging as the preferred options. Tenure over marine estate was strongly supported but may prove difficult to implement in the Philippines. Sex-selective fishing (leaving pregnant males) had moderate support across all groups but may be relatively easy to introduce because of fisher acceptance. In collaboration with international efforts to ensure sustainable trade in Seahorses we recommend that a minimum size limit of 10 cm height and more no-take Marine Protected Areas be implemented as soon as possible to help restore this Seahorse fishery in the Philippines.
Geng Qin - One of the best experts on this subject based on the ideXlab platform.
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effects of chronic exposure to environmental levels of tributyltin on the lined Seahorse hippocampus erectus liver analysis of bioaccumulation antioxidant defense and immune gene expression
Science of The Total Environment, 2021Co-Authors: Lu Tang, Geng Qin, Yanhong Zhang, Xin Wang, Canchuan Zhang, Qiang LinAbstract:Tributyltin (TBT), an organotin compound frequently detected in the coastal environments, poses a threat to aquatic organisms. The lined Seahorse (Hippocampus erectus) is a vulnerable species found in nearshore water habitats. The mechanisms by which this fish responds to TBT exposure are not yet fully understood. Histological, biochemical, and transcriptional analyses were conducted, and the results showed that 60 days of exposure to 50 and 500 ng/L TBT caused significant tin accumulation and liver damage to Seahorses. Antioxidant defenses and immune responses to TBT exposure in the livers of Seahorses were further investigated. The enzymatic activity of superoxide dismutase and malondialdehyde content increased, while catalase activity decreased. Transcriptomic analysis revealed that a series of genes involved in the antioxidant defense system were highly induced to protect the hepatic cells from oxidative damage. TBT exposure also resulted in the induction of genes associated with immune and inflammatory processes, representing a stress response to combat the adverse environmental conditions in the exposed Seahorses. Furthermore, Seahorses showed an increased health risk, according to the elevation of the expression of genes with tumor-promoting effects, when exposed to TBT. These findings contribute to our understanding of the adverse effects of TBT exposure on Seahorses, and their potential defense mechanisms.
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wnt8a is one of the candidate genes that play essential roles in the elongation of the Seahorse prehensile tail
Marine Life Science & Technology, 2021Co-Authors: Bo Zhang, Geng Qin, Yanhong Zhang, Chunlei Cang, Qiang LinAbstract:Seahorses are a hallmark of specialized morphological features due to their elongated prehensile tail. However, the underlying genomic grounds of Seahorse tail development remain elusive. Herein, we evaluated the roles of essential genes from the Wnt gene family for the tail developmental process in the lined Seahorse (Hippocampus erectus). Comparative genomic analysis revealed that the Wnt gene family is conserved in Seahorses. The expression profiles and in situ hybridization suggested that Wnt5a, Wnt8a, and Wnt11 may participate in Seahorse tail development. Like in other teleosts, Wnt5a and Wnt11 were found to regulate the development of the tail axial mesoderm and tail somitic mesoderm, respectively. However, a significantly extended expression period of Wnt8a during Seahorse tail development was observed. Signaling pathway analysis further showed that Wnt8a up-regulated the expression of the tail axial mesoderm gene (Shh), while interaction analysis indicated that Wnt8a could promote the expression of Wnt11. In summary, our results indicate that the special extended expression period of Wnt8a might promote caudal tail axis formation, which contributes to the formation of the elongated tail of the Seahorse.
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effects of tributyltin on gonad and brood pouch development of male pregnant lined Seahorse hippocampus erectus at environmentally relevant concentrations
Journal of Hazardous Materials, 2021Co-Authors: Lu Tang, Geng Qin, Qiang Lin, Yali Liu, Yanhong ZhangAbstract:The male pregnancy of Seahorses is unique, but their reproductive response to environmental disturbances has not yet been clarified. Tributyltin (TBT) is known to have an endocrine disrupting effect on the reproductive system of coastal marine organisms. This study evaluated the potential effects of exposure to environmentally relevant concentrations of TBT on the development of gonads and brood pouch of the lined Seahorse (Hippocampus erectus). Physiological, histological, and transcriptional analyses were conducted, and results showed that high levels of TBT bioaccumulation occurred in male and female Seahorses. TBT led to ovarian follicular atresia and apoptosis with the elevation of androgen levels, accompanied by the induction of genes associated with lysosomes and autophagosomes. Comparative transcriptional analyses revealed the likely inhibition of spermatogenesis via the suppression of cyclic AMP and androgen synthesis. Notably, the transcriptional profiles showed that TBT potentially affects the immune system, angiogenesis, and embryo nourishment of the brood pouch, which indicates that it has negative effects on the male reproductive system of Seahorses. In summary, this study reveals that environmental levels of TBT potentially affect the reproductive efficiency of Seahorses, and may ultimately lead to a reduction in their populations in coastal environments.
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bioaccumulation and reproductive toxicity of bisphenol a in male pregnant Seahorse hippocampus erectus at environmentally relevant concentrations
Science of The Total Environment, 2021Co-Authors: Yali Liu, Geng Qin, Xin Wang, Yu Chen, Qiang LinAbstract:Abstract Seahorses, with brood pouch in adult males, are a bioindicator species that exhibit specialized reproductive strategy of “male pregnancy”. Bisphenol A (BPA), one of the most pervasive endocrine-disrupting chemicals (EDCs), is hazardous for reproductive, immune, and neurological systems. However, no evidence of BPA toxicity to the male-pregnant animals is available. Herein, the reproductive toxicity of BPA was evaluated in lined Seahorses (Hippocampus erectus) following exposure to environmentally relevant concentrations (10, 100, and 1000 μg/L) through physiological, histological, and transcriptional analyses. Our results indicated BPA bioaccumulation to be positively correlated with exposure doses in both sexes. Ovarian failure was only observed in the high-dose BPA treatment group, accompanied by the apoptosis of follicular cells and up-regulation of pro-apoptotic genes. However, brood pouches maintenance were surprisingly inhibited at low concentration, and transcriptomic analysis revealed disturbed profiles of genes involved in the extracellular matrix and cell-cell adhesion pathways. Interestingly, Seahorse testes were less sensitive to BPA exposure than that in other teleosts. Thus, our study suggests that BPA at environmentally relevant concentrations might cause reproductive dysfunction in Seahorses, potentially exerting adverse effects on the Seahorse population since most of them inhabit shallow coastal areas with prevalent estrogenic contaminants.
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environmental estrogens and progestins disturb testis and brood pouch development with modifying transcriptomes in male pregnancy lined Seahorse hippocampus erectus
Science of The Total Environment, 2020Co-Authors: Geng Qin, Bo Zhang, Yanhong Zhang, Yuan Zhang, Yali Liu, Qiang LinAbstract:Abstract Exposure to environmental estrogens and progestins has contributed to adverse effects on the reproduction of many aquatic wildlife species. However, few reports have paid attention to fish species with specialized reproductive strategies, such as male-pregnancy Seahorses. In this study, the potential effects on the behavior, gonad and brood pouch development, and transcriptomic profiles of lined Seahorse Hippocampus erectus exposed to environmentally relevant concentrations of 17α-ethynyl estradiol (EE2, 5 ng/L, 50 ng/L, 10 ng/L, 100 ng/L) or progesterone (P4) for 60 days were examined. Both EE2 and P4 significantly inhibited male brood pouch development by disrupting the extracellular matrix and basement membrane pathways. In addition, both EE2 and P4 impaired the expression of genes associated with spermatogenesis in the testis, and even caused male feminization. We suggest that Seahorses be regarded as a sensitive indicator for evaluating the potential effects of endocrine disrupting chemical (EDC) pollution on aquatic biotic communities.
Dong Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of light intensity stocking density feeding frequency and salinity on the growth of sub adult Seahorses hippocampus erectus perry 1810
Aquaculture, 2009Co-Authors: Dong ZhangAbstract:This investigation examined the effects of light intensity, stocking density, feeding frequency and salinity on the growth of sub-adult Seahorses, Hippocampus erectus and the development of the brood pouch in mate Seahorses. During the 8-week study, Seahorses cultured at a light intensity of 1000 lx had higher incremental wet weight and standard length than those at 100 lx and 2500 lx. Seahorse growth rate decreased with increasing stocking density (0.25, 0.5, 1 and 1.5 inds/L., respectively) during the 10-week study. Male Seahorses grew much faster than females, with incremental wet weights of male and female Seahorses of 6.64 +/- 1.601 g and 5.87 +/- 1.173 g. respectively, in the 0.25 inds/L treatment. The brood pouches of the males emerged earlier, and the ratio between the pouch length and standard length was higher at the higher stocking densities (I and 1.5 inds/L). The final body weight, weight gain (WG) and specific growth rate (SGR) of the male and female Seahorses that were fed 4 times per day were the highest, while those fed 3 times per day had the highest standard length after 10 weeks of culture. The ratio of the length of male brood pouch to standard length was the highest in the low feeding frequency treatment (fed once a day). The incremental wet weight and standard length of sub-adult Seahorses differed significantly among the different salinities (35, 33, 31, 29 and 27 parts per thousand) after 8 weeks of culture (F-4.60 = 18.950, F-4.60 = 9.225, P<0.05) with greatest growth at 31-33%.. Results demonstrated that appropriate light intensity, stocking density, feeding frequency and salinity can improve the growth rate of the sub-adult Seahorses and affect the development of the brood pouch in male Seahorses. (C) 2009 Elsevier B.V. All rights reserved.
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breeding and juvenile culture of the lined Seahorse hippocampus erectus perry 1810
Aquaculture, 2008Co-Authors: Dong Zhang, Qiang Lin, Junda LinAbstract:All Seahorse species worldwide have been placed under CITES Appendix II since 2004, because they have been over-exploited for traditional Chinese medicine and aquarium trades. Aquaculture has been recognized as a long-term solution for sustaining the Seahorse trade while minimizing wild collection. In this study, we evaluated the breeding and juvenile culture of an important aquarium Seahorse species, the lined Seahorse Hippocampus erectus, Perry 1810. Pairing, mating and copulation behavior were observed. Gestation time and brood size were 17.33 +/- 2.94 days and 272.33 +/- 66.45 individuals/brood, respectively. Growth rates differed among juveniles from different broods. Effects of temperature on the growth rates and survivorship of the juveniles during the first two weeks were compared. The highest growth rate and survivorship of the juveniles occurred at 28-29 degrees C among the temperatures tested (24-:33 degrees C). Growth rate and survivorship of the juveniles during the first 9 weeks at 28 C were investigated. The final standard length and survivorship of the juveniles were 6.32 +/- 0.52 cm and 71.11 +/- 10.18%, respectively, and the relationship between the wet weight and the standard length of the juvenile Seahorses can be expressed as: W=0.0034 L-2.5535 (r(2)=0.9903, n=12, P<0.01). These findings suggest that: H. erectus is a good candidate for commercial aquaculture. (C) 2008 Elsevier B.V. All rights reserved.
Amanda C J Vincent - One of the best experts on this subject based on the ideXlab platform.
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global Seahorse trade defies export bans under cites action and national legislation
Marine Policy, 2019Co-Authors: S J Foster, Tingchun Kuo, Anita Kar Yan Wan, Amanda C J VincentAbstract:Abstract Illegal trade undermines efforts to achieve sustainable use of wildlife, including marine fishes. This study investigated the illegal trade of Seahorses, among the first taxa of marine fishes to come under global trade restrictions. Seahorses are listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This designation allows exports of specimens that are sourced sustainably and legally (within CITES rules). However, all countries historically exporting large numbers of Seahorses have since banned trade or are under CITES export suspensions. In particular, Thailand, previously considered the source of about 75% of all wild dried Seahorses, suspended exports in January 2016. To investigate global compliance, 220 interviews were conducted with traders in Hong Kong Specialist Administrative Region (hereafter Hong Kong SAR), the largest entrepot for dried Seahorses. This study sought to understand current sources of Seahorses (2016–17) and relative volumes from each source. Traders reported obtaining dried Seahorses from many countries with bans on Seahorse exports, most notably Thailand and the Philippines. Indeed, it is estimated that almost all dried Seahorses in Hong Kong SAR (95%) were reportedly imported from source countries despite export bans being in place, indicating a widespread lack of enforcement. More broadly, trade regulations, including bans, are likely to be undermined when indiscriminate extraction persists, as with Seahorses in bottom trawls and other non-selective fishing methods. Attention must be directed at managing extraction as well as increasing enforcement of trade bans.
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assessing the changes in international trade of marine fishes under cites regulations a case study of Seahorses
Marine Policy, 2018Co-Authors: Tingchun Kuo, Amanda C J VincentAbstract:Abstract Trade regulations may be useful for conserving marine species that are suffering from overexploitation. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) has emerged as an instrument to help tighten fisheries management. However, the impacts of CITES regulations have not been examined for the trade in fully marine fishes. This study used Seahorses (Hippocampus spp.), the first fully marine fishes listed in CITES Appendix II since treaty inception, as a case study. Drawing on Customs data from Taiwan and Hong Kong SAR (which cover pre-CITES periods), iterative-segmented regressions were applied to investigate changes in Seahorse trade corresponding to CITES interventions. Principal component analyses were conducted to understand characteristics of Seahorse source countries, and a gravity model of trade was applied to identify predictors of Seahorse trade volumes. This study found that the total weight of Seahorses in documented trade decreased significantly after CITES implementation, recorded trade became concentrated in fewer countries, and prices increased. Seahorse source countries were found having more fishers, demersal fish catch and general trade with China, compared to other range states. However, countries that reported no exports, unchanged export volumes or declining volumes after CITES were similar. In addition, volumes traded between two countries were found significantly higher when the two countries were closer together or when the source country had a lower per capita GDP or higher demersal catch. This study can help guide targeted actions to maximize CITES effectiveness for marine species.
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low bycatch rates add up to big numbers for a genus of small fishes
Fisheries, 2017Co-Authors: Julia M Lawson, S J Foster, Amanda C J VincentAbstract:Nonselective fishing gears extract a great many small marine species, with limited documentation or assessment of their impacts. Among those species, Seahorses (genus Hippocampus) are unusual because this genus has been the focus of scientific surveys and international trade regulation. Our review of published and unpublished data sources analyzed data on Seahorse bycatch for five gear-type categories and 22 countries. The median catch per unit effort of Seahorse bycatch across all five gear types was 0.96 Seahorses per vessel−1 day−1. Nonetheless, fleet sizes were so large that annual catches were estimated at approximately 37 million Seahorses across our sampled countries. Fisher interviews suggested that Seahorse catches were declining (although information on changes in effort over time were not available). Furthermore, international export data did not capture the magnitude of Seahorses in bycatch. Our work emphasizes the importance of evaluating bycatch, even for taxa where reported daily catch rate...
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comparing interview and trade data in assessing changes in the Seahorse hippocampus spp trade following cites listing
Oryx, 2016Co-Authors: Joy T L Lam, Heather J Koldewey, Mai Yasue, Amanda C J VincentAbstract:Concerns regarding the sustainability of the Seahorse Hippocampus spp. trade led to their listing on CITES Appendix II in 2002, with implementation in 2004. In 2007 we interviewed wholesale traders of Seahorses in Hong Kong, China, seeking indications of the effects of the CITES listing on the Seahorse trade. We cross-validated traders’ perspectives with government trade statistics (1998–2007) from Hong Kong and Taiwan. We also compared these data with trade statistics for pipefish, which are related species with similar medicinal uses but are not CITES-listed. Both the interviews and government statistics indicated reduced volumes of Seahorses traded through Hong Kong, changes in source countries, and price increases post-implementation. Traders suggested that these changes were largely a result of the CITES listing. However, data indicate that other factors such as shifts in domestic policies and local demand may also have affected the trade. By cross-validating the perspectives of local stakeholders with trade statistics in a wildlife trading hub we were able to explore hypotheses on the local and global impacts of CITES. Such approaches are especially important for CITES-listed species because often there is no single data source that is complete and wholly reliable.
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revisiting two sympatric european Seahorse species apparent decline in the absence of exploitation
Aquatic Conservation-marine and Freshwater Ecosystems, 2012Co-Authors: Iain R Caldwell, Amanda C J VincentAbstract:Seahorses are marine fish with several life history characteristics hypothesized to make them resilient but are of conservation concern because of their international trade and habitat loss. Surveys of two unexploited European Seahorse species (Hippocampus guttulatus and Hippocampus hippocampus) in Ria Formosa lagoon, Portugal, were repeated seven years after their populations in the lagoon were found to be among the densest in the world. Population densities of both species declined significantly between 2001/2002 and 2008/2009 surveys (94% and 73% for H. guttulatus and H. hippocampus respectively). H. guttulatus declines were not associated with any environmental changes measured (i.e. percentage live benthic habitat cover, depth, temperature, water current speed, horizontal visibility). H. hippocampus declined more where current speed had decreased. At the low densities found in 2008/2009, occurrence for both species was best predicted by depth: Seahorses were found in deeper locations throughout the lagoon. Other important predictors were temperature for H. guttulatus (found at sites warmer than average) and current speed for H. hippocampus (found in locations with faster currents). The large declines in Seahorse densities made it difficult to compare results over time. Presence–absence and abundance modelling at multiple scales can help to ensure that data are comparable even when populations fluctuate drastically. Copyright © 2012 John Wiley & Sons, Ltd.
