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Adams L, Wyffels JT, Goodwin B, Munson R, LeBorgne L, Feldheim KA, Lyons K. Monitoring egg fertility, embryonic morbidity, and mortality in an oviparous elasmobranch using ultrasonography. Front Vet Sci 2024; 11:1410377. [PMID: 39139603 PMCID: PMC11319157 DOI: 10.3389/fvets.2024.1410377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 07/11/2024] [Indexed: 08/15/2024] Open
Abstract
Ultrasonography is widely used to monitor pregnancy in viviparous species, but it is underutilized as a tool to characterize embryonic development in oviparous species. Currently, a multi-institutional effort is underway to re-wild the endangered zebra shark (Stegostoma tigrinum) to locations where this species was previously extirpated by leveraging the reproductive efforts of aquarium sharks as a source of brood stock. Zebra sharks are oviparous and fecund, but a large percentage of their yolked eggs do not result in hatchlings. Therefore, ultrasonography represents a potential tool for distinguishing fertile eggs with developing embryos from degrading eggs, and to diagnose changes in early embryonic development predictive of poor outcomes. The objectives of the current study were to use ultrasonography to assess egg fertility, monitor early embryonic development, and identify morphological indicators that may be predictive of early embryonic mortality. Freshly laid eggs from four female zebra sharks were collected and inventoried daily at Aquarium of the Pacific. Eggs were incubated undisturbed for 2 to 4 weeks and subsequently examined weekly via ultrasound to assess fertility and monitor embryo development. Among 120 fertile eggs, embryos were identified as early as 8 days post-oviposition, with average (±SD) time to first observation at 30 ± 7 days. Morphological and behavioral abnormalities were observed for most embryos (n = 84, 70%) as early as 16 days and up to 95 days post-oviposition. Common abnormalities included: bent or curled tails, vesicle(s) at the base of the yolk stalk, and slow or weak movement. Only one embryo survived to hatch during the study and was genetically-confirmed parthenogenetic, suggesting hatching success for parthenotes is low (<1%). Ultrasonography was demonstrated to be an effective and non-invasive method to determine egg fertility, identify embryos with developmental abnormalities, and monitor embryo growth.
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Affiliation(s)
- Lance Adams
- Aquarium of the Pacific, Long Beach, CA, United States
| | - Jennifer T. Wyffels
- Ripley’s Aquariums, Orlando, FL, United States
- Delaware Biotechnology Institute, Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
| | | | - Rachel Munson
- Aquarium of the Pacific, Long Beach, CA, United States
| | | | - Kevin A. Feldheim
- Pritzker Laboratory for Molecular Systematics and Evolution, The Field Museum, Chicago, IL, United States
| | - Kady Lyons
- Center for Species Survival, Georgia Aquarium, Atlanta, GA, United States
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Courtship and Reproduction of the Whitetip Reef Shark Triaenodon obesus (Carcharhiniformes: Carcharhinidae) in an Ex Situ Environment, with a Description of the Late Embryonic Developmental Stage. Animals (Basel) 2022; 12:ani12233291. [PMID: 36496812 PMCID: PMC9737276 DOI: 10.3390/ani12233291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
Elasmobranchs represent a group of species under considerable anthropic pressure because of the scale of industrial and artisanal fisheries and the loss of essential areas for nursery and feeding, which are causing substantial population losses around the world. Reproduction in an ex situ environment enables a healthy population to be built and maintained in networks of public aquariums, increasing our knowledge of elasmobranch reproductive biology and offering the opportunity for reintroductions in areas where native populations have been removed. The study reports two successful pregnancies of the whitetip reef shark Triaenodon obesus, considered a vulnerable species by the International Union for the Conservation of Nature. Copulation and gestation data are provided, including ultrasound recordings of the late stage of embryo development. Ultrasonography was performed with the GE Logiq and convex transducer and revealed a fetus with defined fins and organogenesis, with definition of eyes, gills, liver, a heart with individualized chambers, partially defined kidneys, and a well-defined spiral intestine. A cartilaginous skeleton forming a posterior acoustic shadow was detailed, as well as a moving fetus with a biparietal diameter of 6.47 cm and a heart rate of 62 Beats Per Minute on spectral Doppler. This is the first successful reproduction of T. obesus in an aquarium in Brazil.
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Inoue T, Shimoyama K, Saito M, Wong MKS, Ikeba K, Nozu R, Matsumoto R, Murakumo K, Sato K, Tokunaga K, Kofuji K, Takagi W, Hyodo S. Long-term monitoring of egg-laying cycle using ultrasonography reveals the reproductive dynamics of circulating sex steroids in an oviparous catshark, Scyliorhinus torazame. Gen Comp Endocrinol 2022; 327:114076. [PMID: 35710034 DOI: 10.1016/j.ygcen.2022.114076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/24/2022]
Abstract
The many diverse reproductive strategies of elasmobranchs (sharks, skates and rays) from lecithotrophic oviparity to matrotrophic viviparity have attracted significant research attention. However, the endocrine control of elasmobranch reproduction is less well-documented largely due to their reproductive characteristics, such as a long reproductive cycle, and/or repeated internal fertilization using stored sperm in oviparous species. In the present study, for the first time, we succeeded in non-invasive monitoring of the continuing egg-laying cycle of the cloudy catshark Scyliorhinus torazame using portable ultrasound devices. Furthermore, long-term simultaneous monitoring of the egg-laying cycle and measurement of plasma sex steroids revealed cycling patterns of estradiol-17β (E2), testosterone (T) and progesterone (P4). In particular, a decline in T followed by a reciprocal surge in plasma P4 were consistently observed prior to the appearance of the capsulated eggs, implying that P4 is likely associated with the ovulation and/or egg-case formation. While the cycling pattern of E2 was not as apparent as those of T and P4, threshold levels of E2 (>5 ng/mL) and T (>1 ng/mL) appeared to be crucial in the continuation of egg-laying cycle. The possibility to trace the dynamics of plasma sex steroids in a single individual throughout the reproductive cycles makes the catshark a useful model for regulatory and mechanistic studies of elasmobranch reproduction.
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Affiliation(s)
- Takuto Inoue
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Koya Shimoyama
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Momoko Saito
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Marty Kwok-Shing Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Kiriko Ikeba
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Ryo Nozu
- Okinawa Churashima Research Center, Okinawa Churashima Foundation, 888 Ishikawa, Motobu, Okinawa 905-0206, Japan
| | - Rui Matsumoto
- Okinawa Churashima Research Center, Okinawa Churashima Foundation, 888 Ishikawa, Motobu, Okinawa 905-0206, Japan; Okinawa Churaumi Aquarium, 424 Ishikawa, Motobu, Okinawa 905-0206, Japan
| | - Kiyomi Murakumo
- Okinawa Churaumi Aquarium, 424 Ishikawa, Motobu, Okinawa 905-0206, Japan
| | - Keiichi Sato
- Okinawa Churashima Research Center, Okinawa Churashima Foundation, 888 Ishikawa, Motobu, Okinawa 905-0206, Japan; Okinawa Churaumi Aquarium, 424 Ishikawa, Motobu, Okinawa 905-0206, Japan
| | - Kotaro Tokunaga
- Ibaraki Prefectural Oarai Aquarium, Oarai, Ibaraki 311-1301, Japan
| | - Kazuya Kofuji
- Ibaraki Prefectural Oarai Aquarium, Oarai, Ibaraki 311-1301, Japan
| | - Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
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Ito T, Furuya M, Sasai K. The Establishment of an Optimal Protocol for Contrast-Enhanced Micro-Computed Tomography in the Cloudy Catshark Scyliorhinus torazame. JOURNAL OF AQUATIC ANIMAL HEALTH 2021; 33:264-276. [PMID: 34363233 DOI: 10.1002/aah.10143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
The purpose of this study was to determine the optimal imaging protocol for contrast-enhanced computed tomography (CECT) using micro-CT (μ-CT) for the posterior cardinal vein (PCV), dorsal aorta (DA), hepatic portal vein (HPV), kidney, liver, cephalic arteries (CAs), and gills of Cloudy Catsharks Scyliorhinus torazame. Additionally, we examined the availability of CECT screening for the coelomic organs. Different doses of iopamidol (100, 300, 500, and 700 mg iodine [mgI]/kg) were administered intravenously for 20 s in six sharks. The CT scans from the pectoral girdle to the pelvic girdle were performed at 0-600 s after administration. Contrast-enhanced CT imaging of the CAs, gills, and coelomic organs was examined. Assessment of the signal enhancement value revealed that the PCV was easily visualized with all contrast doses at 25 s. The CAs, gills, and DA were visible at a slightly higher dose (CAs and gills: 200 mgI/kg at 40 s; DA: 300 mgI/kg at 50 s). The HPV was obvious at a dose of at least 500 mgI/kg after a 150-s delay. The parenchyma of the kidney had a contrast effect at 300 mgI/kg, 150 s after the contrast effect of the renal portal system disappeared. The liver, which stores a lot of lipids, had poor overall contrast enhancement that was optimized at the highest dose of 700 mgI/kg. Contrast-enhanced CT screening at 700 mgI/kg and 150 s is likely to obtain the optimal imaging of the reproductive organs, such as the ovary, oviducal gland, uterus, and testis. The present findings can be applied not only to clinical practice but also to academic research and education on elasmobranchs in aquariums.
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Affiliation(s)
- Takaomi Ito
- Osaka Aquarium Kaiyukan, 1-1-10 Kaigandori, Minato-ku, Osaka, 5520022, Japan
| | - Masaru Furuya
- Laboratory of Veterinary Internal Medicine, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Orai Kita, Izumisano, Osaka, 5988531, Japan
| | - Kazumi Sasai
- Laboratory of Veterinary Internal Medicine, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Orai Kita, Izumisano, Osaka, 5988531, Japan
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Jorgensen SJ, Micheli F, White TD, Van Houtan KS, Alfaro-Shigueto J, Andrzejaczek S, Arnoldi NS, Baum JK, Block B, Britten GL, Butner C, Caballero S, Cardeñosa D, Chapple TK, Clarke S, Cortés E, Dulvy NK, Fowler S, Gallagher AJ, Gilman E, Godley BJ, Graham RT, Hammerschlag N, Harry AV, Heithaus M, Hutchinson M, Huveneers C, Lowe CG, Lucifora LO, MacKeracher T, Mangel JC, Barbosa Martins AP, McCauley DJ, McClenachan L, Mull C, Natanson LJ, Pauly D, Pazmiño DA, Pistevos JCA, Queiroz N, Roff G, Shea BD, Simpfendorfer CA, Sims DW, Ward-Paige C, Worm B, Ferretti F. Emergent research and priorities for shark and ray conservation. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01169] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Becerril-García EE, Arellano-Martínez M, Bernot-Simon D, Hoyos-Padilla EM, Galván-Magaña F, Godard-Codding C. Steroid hormones and chondrichthyan reproduction: physiological functions, scientific research, and implications for conservation. PeerJ 2020. [DOI: 10.7717/peerj.9686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The study of the reproductive aspects of chondrichthyans through the analysis of steroid hormones has been carried out for more than five decades in several species around the world. This scientific knowledge constitutes the basis of the reproductive endocrinology of chondrichthyans, which has provided information regarding their sexual maturation, gametogenesis, mating seasons, gestation periods, and parturition. The present review summarises the existing literature on steroid hormones in chondrichthyan reproduction and identifies future research directions addressing critical knowledge gaps in the reproductive physiology of this taxon. A total of 59 peer reviewed scientific papers from 1963 to 2020 were reviewed and the following parameters analysed: species, steroid hormones, biological matrix, field sampling (year, location), and methodology (assays, sample size, precision, and recoveries). We provided a summary of the methods, biological matrices, and the functions of up to 19 hormones on the biology of 34 species of chondrichthyans that have been analysed to date. The majority of the studies used radioimmunoassay as the main methodology (76.3%; n = 45/49); while the most frequent biological matrix used was plasma (69.5%; n = 41/49). A Kernel’s heat map was generated to present the scientific effort according to geographic location and evidenced a lack of research in high biodiversity areas for chondrichthyans worldwide. The implications of the study of steroid hormones for the conservation of chondrichthyans are discussed, as only 2.9% of the species of this group have been analysed and most of the scientific effort (93.2%; n = 55/59 papers) has focused on the analysis of less than six hormones.
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Affiliation(s)
| | | | - Daniela Bernot-Simon
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, La Paz, Mexico
| | | | - Felipe Galván-Magaña
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Mexico
| | - Céline Godard-Codding
- The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, USA
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Penfold LM, Wyffels JT. Reproductive Science in Sharks and Rays. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1200:465-488. [PMID: 31471806 DOI: 10.1007/978-3-030-23633-5_15] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sharks and rays make up 96% of the class Chondrichthyes. They are among the most endangered of any taxa, threatened through habitat loss, overfishing and hunting for shark fin soup, traditional medicines or sport, and because many species are slow to mature and produce low numbers of offspring. Sharks and rays are ecologically and reproductively diverse, though basic knowledge of their reproductive physiology is lacking for many species. There has been a move towards non-lethal approaches of data collection in sharks and rays, especially with reproductive technologies such as ultrasound and hormone analysis. Additionally, technologies such as semen collection and artificial insemination are lending themselves to develop tools to manage small or closed populations, with cold-stored sperm being shipped between institutions to maximize genetic diversity in managed populations. The role of steroid hormones in elasmobranch reproduction appears broadly conserved, though heavily influenced by environmental cues, especially temperature. For this reason elasmobranchs are likely at risk of reproductive perturbations due to environmental changes such as ocean warming. Current reproductive technologies including computer assisted sperm assessments to study warming effects on sperm motility and intra-uterine satellite tags to determine birthing grounds will serve to generate data to mitigate anthropogenic changes that threaten the future of this vulnerable groups of fish.
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Affiliation(s)
- Linda M Penfold
- South-East Zoo Alliance for Reproduction & Conservation, Yulee, FL, USA.
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