scholarly journals Use of Synthetic Salmon GnRH and Domperidone (Ovaprim®) in Sharks: Preparation for ex situ Conservation

2020 ◽  
Vol 7 ◽  
Author(s):  
Sang Wha Kim ◽  
Won Hee Hong ◽  
Se Jin Han ◽  
Jun Kwon ◽  
Heejun Ko ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Marine Ecosystem ◽  
Keystone Species ◽  
Optimal Dose ◽  
Ex Situ ◽  
Injection Timing ◽  
Shark Species ◽  
Apex Predators ◽  
Marine Food Chain ◽  
Marine Food

Shark populations are constantly decreasing owing to environmental destruction and overfishing; thus, sharks are now at a risk of extinction, with 27.9% of shark species classified as endangered on the International Union for Conservation of Nature’s Red List. Sharks are apex predators and a keystone species in balancing the marine food chain; their extinction will create an imbalance of the entire marine ecosystem. Assisted reproductive technology is the last resort for protecting animals facing severe extinction. Here, as a proactive effort toward building a hormone-induced artificial insemination protocol for endangered wild sharks, we identified the possibility of germ cell maturation by administration of Ovaprim®, a commercially produced synthetic salmon gonadotropin-releasing hormone, and calculated its optimum dosage and injection timing. The experiment was conducted on two shark species—Triakis scyllium and Carcharhinus longimanus. We found that intramuscular injections of 0.2 mL/kg of Ovaprim® for male T. scyllium and C. longimanus, 0.2 mL/kg + 0.5 mL/kg at a 24 h interval for female T. scyllium, and 0.2 mL/kg + 0.2 mL/kg or 0.2 mL/kg + 0.3 mL/kg at a 24 h interval for female C. longimanus were optimal dose protocols. These doses effectively induced the maturation and ovulation of oocytes and the release of semen. Our results confirm that Ovaprim® is a suitable tool for shark hormone-induced artificial insemination and indicate that this method may enable the conservation of the endangered shark species.

scholarly journals Persepsi Nelayan Terhadap Status Konservasi Hiu dan Pengaruhnya Terhadap Penangkapan Hiu: Studi Kasus di Kabupaten Badung, Provinsi Bali

2017 ◽  
Vol 4 (2) ◽  
pp. 244 ◽  
Author(s):  
Eriq Imanuel ◽  
I Gede Hendrawan ◽  
Ni Luh Putu Ria Puspitha
Keyword(s):  
Food Chain ◽  
Local Community ◽  
Conservation Status ◽  
Shark Species ◽  
Top Predator ◽  
Protected Species ◽  
Marine Food Chain ◽  
Marine Food ◽  
Shark Conservation ◽  
And Control

Shark is one of top predator that can define and control marine food chain. Shark breeding process is relatively slow and increase of catching activity has even given worse impact to shark population. Several endangered shark species has already protected the catch activity was banned. Some of them, such as Alopias superciliosus are found in Benoa and Kedonganan harbour. This condition happened because of  not enough information and knowledge transfer to the local community about the protected species and catching regulation. Based on that information,the research about fishermen perception on shark conservation status and its correlation with the shark catch is important to be conducted. Data was collected using quisioner through interview approach. All the respondent is men with the age ranged from 16-67 years old, and 98% of respondent is labor. About 55% of the respondent graduated from elementary school. The result showed that the fisherman perception of shark conservation status categorized as good, while shark catch that is related with conservation in Badung district is categorized very good. The correlation of fisherman perception to shark conservation status with shark catching effort is negative, and significant to the shark catching effort (?=0,05) in Badung district. It means that if the fisherman perception to the shark conservation status in Badung district increased, so that the catch effort will be decrease.

scholarly journals Reproductive Anatomy of Chondrichthyans: Notes on Specimen Handling and Sperm Extraction. II. Sharks and Chimaeras

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2191
Author(s):  
Pablo García-Salinas ◽  
Victor Gallego ◽  
Juan F. Asturiano
Keyword(s):  
Artificial Insemination ◽  
Captive Breeding ◽  
Ex Situ ◽  
Specimen Handling ◽  
Viable Sperm ◽  
Abdominal Massage ◽  
Reproductive Anatomy ◽  
Conservation Projects ◽  
Breeding Techniques

The chondrichthyan fishes, which comprise sharks, rays, and chimaeras, are one of the most threatened groups of vertebrates on the planet. Given this situation, an additional strategy for the protection of these species could be the ex situ conservation projects developed in public aquaria and research centers. Nevertheless, to increase sustainability and to develop properly in situ reintroduction strategies, captive breeding techniques, such as sperm extraction and artificial insemination, should be developed. These techniques are commonly used in other threatened species and could be also used in chondrichthyans. However, the different reproductive morphologies found in this group can complicate both processes. Therefore, a comparison of the reproductive anatomy of eight distinct chondrichthyans, with an emphasis on those important differences when performing sperm extraction or artificial insemination, is carried out herein. Sharks and chimaeras belonging to the Scyliorhinidae, Carcharhinidae, Centrophoridae, Etmopteridae, Hexanchidae, and Chimaeridae families were obtained from commercial fisheries, public aquaria, and stranding events. In addition, the process of obtaining viable sperm samples through cannulation, abdominal massage, and oviducal gland extraction is described in detail for both living and dead animals.

scholarly journals SMFC as a tool for the removal of hydrocarbons and metals in the marine environment: a concise research update

2021 ◽  
Author(s):  
Edvige Gambino ◽  
Kuppam Chandrasekhar ◽  
Rosa Anna Nastro
Keyword(s):  
Marine Environment ◽  
Microbial Fuel Cells ◽  
Energy Production ◽  
Marine Pollution ◽  
Future Perspectives ◽  
Sediment Remediation ◽  
Marine Food Chain ◽  
Marine Food ◽  
Accumulation Of Pollutants ◽  
Insight Into

AbstractMarine pollution is becoming more and more serious, especially in coastal areas. Because of the sequestration and consequent accumulation of pollutants in sediments (mainly organic compounds and heavy metals), marine environment restoration cannot exempt from effective remediation of sediments themselves. It has been well proven that, after entering into the seawater, these pollutants are biotransformed into their metabolites, which may be more toxic than their parent molecules. Based on their bioavailability and toxic nature, these compounds may accumulate into the living cells of marine organisms. Pollutants bioaccumulation and biomagnification along the marine food chain lead to seafood contamination and human health hazards. Nowadays, different technologies are available for sediment remediation, such as physicochemical, biological, and bioelectrochemical processes. This paper gives an overview of the most recent techniques for marine sediment remediation while presenting sediment-based microbial fuel cells (SMFCs). We discuss the issues, the progress, and future perspectives of SMFC application to the removal of hydrocarbons and metals in the marine environment with concurrent energy production. We give an insight into the possible mechanisms leading to sediment remediation, SMFC energy balance, and future exploitation.

Long-term migration patterns and bisexual philopatry in a benthic shark species

2017 ◽  
Vol 68 (8) ◽  
pp. 1414 ◽  
Author(s):  
Nathan Charles Bass ◽  
Johann Mourier ◽  
Nathan A. Knott ◽  
Joanna Day ◽  
Tristan Guttridge ◽  
...  
Keyword(s):  
Management Strategies ◽  
Movement Patterns ◽  
Conclusive Evidence ◽  
Migration Route ◽  
Shark Species ◽  
Apex Predators ◽  
Arrival Times ◽  
And Bisexual ◽  
Australian Coastline ◽  
Port Jackson

Knowledge of the broad-scale movement patterns of sharks is essential to developing effective management strategies. Currently there is a large bias in studies focusing on species that are either large apex predators or found in tropical to subtropical regions. There is limited knowledge of the movements and migrations of benthic and temperate shark species. The present study used passive acoustic telemetry to investigate the movement patterns of a benthic shark species, the Port Jackson shark (Heterodontus portusjacksoni). Individuals were tagged with acoustic transmitters between 2012 and 2014 and their movements were monitored within Jervis Bay and along the east Australian coastline for up to 4 years. Male and female Port Jackson sharks demonstrated high levels of philopatry to both Jervis Bay and their tagging location across multiple years. Although males and females did not differ in their arrival times, females departed from Jervis Bay later than males. Approximately half the tagged individuals migrated in a southward direction, with individuals being detected at Narooma, Bass Strait and Cape Barron Island. This study provides conclusive evidence of bisexual philopatry in a benthic temperate shark species, confirming previous hypotheses, and presents the most detailed migration route for Port Jackson sharks to date.

scholarly journals Uptake and trophic changes in polybrominated diphenyl ethers in the benthic marine food chain in southwestern British Columbia, Canada

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 20-51
Author(s):  
Brenda Burd ◽  
Chris Lowe ◽  
Carmen Morales-„Caselles ◽  
Marie Noel ◽  
Peter Ross ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Polybrominated Diphenyl Ethers ◽  
Dry Weight ◽  
Trophic Levels ◽  
Marine Food Chain ◽  
Deposit Feeders ◽  
Diphenyl Ethers ◽  
Bottom Fish ◽  
Harbour Sediment ◽  
Marine Food

We examined the physical and geochemical effects of sediment on the uptake of polybrominated diphenyl ethers (PBDEs) into marine sediment feeders and their transfer to higher trophic fauna. Sediment PBDEs increased with % total organic carbon (%TOC), organic carbon (OC) flux and grain size (%fines). Tissue PBDE variance was best explained ( R2 = 0.70) by sediment acid volatile sulfides (AVS), PBDEs, and organic lability and input, with the highest values near wastewater outfalls. Dry weight tissue/sediment PBDEs declined with increasing sediment PBDEs, resulting in tissue dilution (ratio <1) at >10 000 pg/g in harbours. Ratios also decreased with increasing %fines, resulting in regional differences. These patterns imply that high levels of fines and high sediment concentrations make PBDEs less bioavailable. Dry weight PBDEs increased >100× between background deposit feeders and predators (polychaetes, crabs, bottom fish, seal), but lipid normalized PBDEs barely increased (<1.3%), suggesting remarkably high uptake in low-lipid sediment feeders, and that PBDEs don’t accumulate at higher trophic levels, but lipid content does. Filter feeders had lower lipid-normalized PBDEs than deposit feeders, highlighting the importance of food resources in higher trophic fauna for bioaccumulation. The most profound congener change occurred with sediment uptake, with nona/deca-BDEs declining and tetra-hexa-BDEs increasing. Harbour sediment feeders had more deca-BDEs than other samples, suggesting PBDEs mostly pass unmodifed through them. Deca-BDEs persist patchily in all tissues, reflecting variable dependence on sediment/pelagic food.

scholarly journals Risk Assessment for Key Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem Under Combined Ocean Acidification and Warming

Ecosystems ◽  
2021 ◽  
Author(s):  
Maartje Oostdijk ◽  
Erla Sturludóttir ◽  
Maria J. Santos
Keyword(s):  
Ocean Acidification ◽  
Atlantic Cod ◽  
Marine Ecosystem ◽  
Keystone Species ◽  
Ecosystem Model ◽  
The Arctic ◽  
Predatory Fish ◽  
Important Species ◽  
Cascading Effects ◽  
Icelandic Waters

AbstractThe Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of these processes in comparison with global average speeds. Here, we use the Atlantis ecosystem model to assess how the trophic network of marine fishes and invertebrates in the Icelandic waters is responding to the combined pressures of OA and warming. We develop an approach where we first identify species by their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We then use literature-determined ranges of sensitivity to OA and warming for different species and functional groups in the Icelandic waters to parametrize model runs for different scenarios of warming and OA. We found divergent species responses to warming and acidification levels; (mainly) planktonic groups and forage fish benefited while (mainly) benthic groups and predatory fish decreased under warming and acidification scenarios. Assuming conservative harvest rates for the largest catch-value species, Atlantic cod, we see that the population is projected to remain stable under even the harshest acidification and warming scenario. Further, for the scenarios where the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase, likely due to a reduction in competition and predation. These results highlight the interdependencies of multiple global change drivers and their cascading effects on trophic organization, and the continued high abundance of an important species from a socio-economic perspective in the Icelandic fisheries.

Feeding habits and trophic level of the smooth hammerhead shark, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), off Ecuador

2018 ◽  
Vol 99 (3) ◽  
pp. 673-680 ◽  
Author(s):  
Colombo Estupiñán-Montaño ◽  
Luis Cedeño-Figueroa ◽  
José F. Estupiñán-Ortiz ◽  
Felipe Galván-Magaña ◽  
Alejandro Sandoval-Londoño ◽  
...  
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Trophic Niche ◽  
Commercial Fishing ◽  
Dosidicus Gigas ◽  
Apex Predators ◽  
Marine Food Webs ◽  
Fishing Vessels ◽  
Marine Food ◽  
Index Of Relative Importance

As apex predators, sharks are known to play an important role in marine food webs. Detailed information on their diet and trophic level is however needed to make clear inferences about their role in the ecosystem. A total of 335 stomachs of smooth hammerhead sharks, Sphyrna zygaena, were obtained from commercial fishing vessels operating in the Ecuadorian Pacific between January and December 2004. A total of 53 prey items were found in the stomachs. According to the Index of Relative Importance (%IRI), cephalopods were the main prey (Dosidicus gigas, Sthenoteuthis oualaniensis, Ancistrocheirus lesueurii and Lolliguncula [Loliolopsis] diomedeae). Sphyrna zygaena was thus confirmed to be a teutophagous species. The estimated trophic level of S. zygaena was between 4.6 and 5.1 (mean ± SD: 4.7 ± 0.16; males: 4.7; females: 4.8). Levin's index (BA) was low (overall: 0.07; males: 0.08; females: 0.09), indicating a narrow trophic niche. We found that sharks <150 cm in total length consumed prey of coastal origin, whereas sharks ≥150 cm foraged in oceanic waters and near the continental shelf. The analyses indicate that S. zygaena is a specialized predator consuming mainly squids.

Cenozoic Marine Diatom Biostratigraphy and Applications to Paleoclimatology and Paleoceanography

1995 ◽  
Vol 8 ◽  
pp. 107-118 ◽  
Author(s):  
John A. Barron ◽  
Jack G. Baldauf
Keyword(s):  
Marine Diatom ◽  
Paleoenvironmental Reconstruction ◽  
Photic Zone ◽  
Marine Diatoms ◽  
Sedimentary Sequences ◽  
Marine Food Chain ◽  
Current State ◽  
Aqueous Environments ◽  
Biostratigraphic Correlation ◽  
Marine Food

Diatoms, golden brown algae, are present in most aqueous environments. Within the marine environment marine diatoms occupy the photic zone and represent the lowest level of the marine food chain. Diatoms are either planktonic or benthic and possess an external siliceous skeleton or frustule, that is boxlike in structure. The size of diatom frustules ranges from less than 1 μm to more than 1,000 μm, but most frustules range in size from 10 to 100 μm. Diatoms are present in the geological record from at least the Cretaceous (Harwood and Nikolaev, this volume) and have numerous advantages for biostratigraphic correlation and paleoenvironmental reconstruction of marine sedimentary sequences. This chapter summarizes the current state of marine diatom biostratigraphy for the Cenozoic and provides examples of how marine diatoms are used in paleoenvironmental reconstructions. No attempt is made to illustrate the various diatom taxa discussed; the reader is referred to published references such as the syntheses of Fenner (1985) and Barron (1985).

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