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1.
Serial ultrasound examination of four mature female sevengill sharks (Notorynchus cepedianus) was carried out over 18 months. Monitoring the reproductive cycle and development of follicles and fetuses in sharks in a noninvasive manner using this technique has not been reported previously. Sharks were caught out of the “Oceanarium” tank by divers using a specially made catch‐out bag, and brought to a holding area for examination. A behavior scoring system was used to monitor the impact of regular handling on the well‐being of the animals. Ultrasound showed the growth and regression of follicles in sevengill ovaries, and allowed an approximation of the reproductive stage of these sharks. Monitoring behavior at five time points during the procedure showed that regular handling of sharks for clinical studies could be done with minimal impact on animal welfare. The ability to follow reproductive events in elasmobranches using ultrasonography is an important step in the application of assisted reproductive technology in these species. Assisted reproductive technology, such as monitoring female reproductive cycles and artificial insemination, could potentially be used to maintain genetic diversity and compliment aquaria‐based breeding programs for endangered species such as the gray nurse shark (Carcharias taurus). Zoo Biol 26:383–395, 2007. © 2007 Wiley‐Liss, Inc. 相似文献
2.
Kenneth J. Saville Andrea M. Lindley Eleanora G. Maries Jeffrey C. Carrier Harold L. Pratt Jr. 《Environmental Biology of Fishes》2002,63(3):347-351
For over a decade, we have been studying the reproductive behavior of the nurse shark, Ginglymostoma cirratum, in the Dry Torugas off the Florida Keys, an important mating and nursery ground for this species. In the course of these studies, we have used a variety of tags and tagging protocols to monitor individual animals. Here we report the use of molecular methods for the genetic analysis of nurse sharks. Specifically we have analyzed genetic variation at the MHC II alpha locus using the polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis of the amplified products. We found this technique to be a relatively rapid and reliable method for identifying genetic differences between individual sharks. Applying this method to a family of sharks consisting of a mother and 32 pups, we demonstrate that at least four fathers must have fathered this brood. Multiple paternity in the nurse shark suggests a mechanism by which populations of this species may maximize genetic variability. This seems especially valuable for philopatric species whose migratory movement, and thus potential for genetic diversity, is limited. 相似文献
3.
Agathe Pirog Hélène Magalon Thomas Poirout Sébastien Jaquemet 《Journal of fish biology》2019,95(5):1195-1206
To improve understanding of bull shark Carcharhinus leucas reproductive biology, we analysed reproductive traits from 118 bull sharks caught along Reunion Island coasts (Western Indian Ocean), including 16 gravid females. Specific microsatellite loci were used to investigate the frequency of multiple paternity. Males and females reached maturity at c. 234 cm and 257 cm total length (LT), respectively, and litter sizes ranged from 5 to 14 embryos. Analysis of the 16 litters collected in various months of the year indicated that parturition occurs between October and December, with a size at birth c. 60–80 cm LT and that the gestation period is probably c. 12 months. Assuming a 1 year resting period and a period of sperm storage (4–5 months) between mating (in June–September) and fertilisation, the reproductive cycle of bull sharks at Reunion Island would be biennial. At least 56.25% of the litters investigated were polyandrous, sired by 2–5 males. Several males that each sired several litters conceived during the same or distinct mating seasons were detected, suggesting both a seasonal aggregation of sharks to mate and some male fidelity to mating site. Altogether, these findings provide valuable information for both shark risk management and conservation of the species in the Western Indian Ocean. 相似文献
4.
Taketeru Tomita Kiyomi Murakumo Keiichi Ueda Hiroshi Ashida Rina Furuyama 《Ethology : formerly Zeitschrift fur Tierpsychologie》2019,125(2):122-126
Underwater ultrasound, a new tool for observing the internal body parts of aquatic animals by scuba divers, allowed us long‐term and frequent observations of the embryos of captive aquatic vertebrates. New ultrasound data of captive tawny nurse sharks (Nebrius ferrugineus) revealed that their embryos frequently migrate between the right and left uteri during gestation. This report is the first reliable evidence of active embryonic locomotion in live‐bearing vertebrates and is contradictory to the concept of “sedentary embryo” which has mainly arisen from studies of mammals. The tawny nurse shark is unique among orectolobiform sharks, in which the embryo develops by feeding on sibling eggs in utero. Thus, we hypothesized that swimming aids in an efficient search and capture of these eggs in the uterine environment. 相似文献
5.
Toby S. Daly-Engel R. Dean Grubbs Kim N. Holland Robert J. Toonen Brian W. Bowen 《Environmental Biology of Fishes》2006,76(2-4):419-424
We tested for presence or absence of multiple paternity in single litters from each of three congeneric shark species in Hawaii: the sandbar shark, Carcharhinus plumbeus, bignose shark, Carcharhinus altimus, and Galapagos shark, Carcharhinus galapagensis. Based on eight polymorphic microsatellite loci, we excluded paternity by a single sire in sandbar and bignose sharks, but could not exclude a single sire for the litter from the Galapagos shark. This study doubles the number of shark species tested for multiple paternity, and is the first demonstration of multiple paternity in sandbar and bignose sharks. 相似文献
6.
Kathryn A. Ayres James T. Ketchum Rogelio González-Armas Felipe Galván-Magaña Alex Hearn Fernando R. Elorriaga-Verplancken Edgar M. Hoyos-Padilla Stephen M. Kajiura 《Journal of fish biology》2021,99(5):1735-1740
Cabo Pulmo National Park was established in 1995 and has since seen a large increase in fish biomass. An unoccupied aerial vehicle (UAV) was used to survey shallow coastal habitat in which lemon sharks (Negaprion brevirostris), bull sharks (Carcharhinus leucas) and Pacific nurse sharks (Ginglymostoma unami) were recorded. Sharks were more common in the afternoon, potentially using warmer shallow areas to behaviourally thermoregulate. This study highlights UAV surveying to be a viable tool for species identification, a limitation of previous terrestrial surveys conducted in the area. 相似文献
7.
Shawn Larson Jeff Christiansen Denise Griffing Jimiane Ashe Dayv Lowry Kelly Andrews 《Conservation Genetics》2011,12(3):679-690
The bluntnose sixgill shark (Hexanchus griseus) is a widely distributed species found in tropical and temperate waters of every ocean, yet we know relatively little about
their basic biology including their life history and population structure. From 2003–2007, we collected over 300 biopsy samples
from sixgills during research operations in Puget Sound, WA, USA. Genotypic data using ten polymorphic microsatellites were
used to describe sixgill genetic diversity, relatedness and mating pattern. Diversity within sixgills was found to be moderate
with an average observed heterozygosity of 0.45, an average expected heterozygosity of 0.61, an average of 12 alleles per
locus, and an average allelic richness of eight within microsatellite loci. Our data suggests all of the sampled individuals
come from one intermixing population, and we found no historical evidence of significant population bottlenecks. Many of the
sharks were sampled using longline techniques with several sharks captured at the same time and place. Similarly, multiple
sharks were sampled on several occasions during research events at the Seattle Aquarium. The proportion of individuals that
were full- or half-siblings was high among sharks sampled at the same time and place (range 0.65–0.87). Analysis of the genetic
relationship between one large female washed ashore and 71 of her near-term pups suggested a polyandrous mating system with
as many as nine males contributing to her offspring. This study is the first to investigate genetic diversity, relatedness
and paternity within sixgill sharks and sheds light on important conservation implications for this little known shark population. 相似文献
8.
Defining the location and habitat characteristics of areas of aggregation of Atlantic shark species has been identified as
an important information need for current and future management efforts. The primary objective of this project was to investigate
the depths and temperatures of the waters occupied by large juvenile sandbar sharks of the northwest Atlantic population during
the winter months and the overwintering localities of these animals using a fishery independent method. During the summer
of 2003, 21 sandbar sharks captured in the Eastern Shore of Virginia bays and lagoons were outfitted with satellite transmitters
that were programmed to detach during the following winter. The sharks occurred in significantly colder and deeper waters
during the winter period than during the summer nursery period with a mean depth and temperature recorded by the transmitters
during the winter period of 19.9°C and 20.8 m and a mean depth and temperature recorded during the summer period of 24.0°C
and 4.3 m. Despite this decrease in temperature and increase in depth of occurrence, the sharks remained in relatively warm
waters and shallow depths throughout the overwintering period. Satellite pop-off locations during the overwintering period
were concentrated in central North Carolina coastal waters, where a unique combination of shallow depths and warm temperatures
may contribute to the survivorship of these animals while they overwinter in these waters. 相似文献
9.
Catch composition and aspects of the biology of sharks caught by Thai commercial fisheries in the Andaman Sea
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Catch composition, landing patterns and biological aspects of sharks caught by commercial fishing fleet operating in the Andaman Sea were recorded from landing sites in Ranong province of Thailand over a period of 1 year. Of the 64 species previously reported in the existing Thailand checklist, only 17 species were recorded in this study. Shark landings from the Andaman Sea appear now to be dominated largely by bamboo sharks Chiloscyllium spp. (Hemiscylliidae), which contribute c. 65% of the total number of sharks recorded. The carcharhinid sharks comprised c. 30·5% to the total catch, while the remaining c. 4·5% of landings comprised sharks from the families Squalidae, Stegostomatidae, Sphyrnidae and Triakidae. The catch composition is remarkably different from the previous landing survey in 2004, in that the current study found noticeable declines in landings of slow‐growing, late‐ maturing and low‐fecundity species (especially sphyrnid and carcharhinid species). The absences of many species and changes in life‐stage composition suggest that the populations of these groups may be close to collapse. The results from this study emphasize the urgency for additional research and monitoring efforts and also the need for management incentives in order to manage shark fisheries effectively in the Andaman Sea. 相似文献
10.
Manire CA Rasmussen LE Maruska KP Tricas TC 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,148(4):926-935
Serum corticosterone was previously studied in numerous elasmobranch fishes (sharks, skates and rays), but the role of this steroid, widespread throughout many taxa, has yet to be defined. The goal of this study was to test whether corticosterone varied in response to acute and chronic capture stress, and across the reproductive cycle in the bonnethead shark, Sphyrna tiburo, and Atlantic stingray, Dasyatis sabina. Serum corticosterone in S. tiburo increased following capture and again 24 h post-capture, possibly caused by interference with 1α-hydroxycorticosterone, the primary stress hormone in elasmobranchs. Higher serum concentrations in males compared to females were observed in both species. Variations in corticosterone also occurred during the reproductive cycle in both species. Consistent with other taxa, elevations in male bonnethead sharks and stingrays coincided with peak testicular development and mating. Elevations in female bonnethead sharks occurred from the time of mating through sperm storage into early gestation. In contrast, corticosterone levels in female stingrays were low during their protracted mating season, but elevated through late gestation and parturition. These results indicate that corticosterone has a limited role, if any, in acute and chronic stress associated with capture in S. tiburo, but likely has physiological functions associated with its glucocorticoid properties across the reproductive cycle of both species. 相似文献
11.
Papastamatiou YP Lowe CG 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2005,141(2):210-214
Vertebrates differ in their regulation of gastric acid secretion during periods of fasting, yet it is unknown why these differences occur. Elasmobranch fishes are the earliest known vertebrates to develop an acid secreting stomach and as such may make a good comparative model for determining the causative factors behind these differences. We measured gastric pH and temperature continuously during periods of fasting in captive free-swimming nurse sharks (Ginglymostoma cirratum) using autonomous pH/temperature data-loggers. All nurse sharks secreted strong gastric acids (minimum pH 0.4) after feeding; however, for most of the sharks, pH increased to 8.2-8.7, 2-3 days after feeding. Half of the sharks also exhibited periodic oscillations in pH when the stomach was empty that ranged from 1.1 to 8.7 (acid secretion ceased for 11.3 +/- 4.3 h day(-1)). This is in contrast to the gastric pH changes observed from leopard sharks (Triakis semifasciata) in a previous study, where the stomach remains acidic during fasting. The leopard shark is a relatively active, more frequently feeding predator, and continuous acid secretion may increase digestive efficiency. In contrast, the nurse shark is less active and is thought to feed less frequently. Periodic cessation of acid secretion may be an energy conserving mechanism used by animals that feed infrequently and experience extended periods of fasting. 相似文献
12.
Metabolic rates and the energetic cost of external tag attachment in juvenile blacktip sharks Carcharhinus limbatus
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This study reports on the metabolic rate of the blacktip shark Carcharhinus limbatus and the energetic costs of external tag attachment. Metabolic rates, swimming speed and tail‐beat (BT) frequency were measured in a static respirometer with untagged animals and animals equipped with a small data logger. Tagged sharks showed significantly higher routine oxygen consumption and lower swimming speeds than untagged animals, indicating that tagging significantly affected the swimming efficiency and energetic requirements in these small sharks, and that these effects must be accounted for when interpreting telemetry data from free‐ranging individuals. 相似文献
13.
Luciana C. Ferreira André S. Afonso Pedro C. Castilho Fábio H. V. Hazin 《Environmental Biology of Fishes》2013,96(6):735-745
The nurse shark, Ginglymostoma cirratum, is an abundant coastal species widely distributed on both sides of the tropical and subtropical Atlantic Ocean. Despite being an endangered species in Brazil, information on bio-ecological aspects of this species is still very scarce. This study investigates seasonal fluctuations in abundance, sex ratio and residency of nurse sharks in coastal waters off Recife, northeastern Brazil. Total length of the specimens caught ranged from 107 to 300 cm. Sex ratio for nurse sharks was 1.31♀:1♂ but it showed a strong variation throughout the year. About 8% of tagged sharks were recaptured after an average of 248 days at liberty, at distances between 0.04 and 6.23 km from the tagging site. A growth rate of 15.77?±?2.53 cm/yr was obtained from total length data collected from three recaptured specimens. Nurse sharks demonstrated some signs of affinity for temperatures between 25º and 30°C and salinities between 34 and 37. The combined analysis of longline and telemetry data indicated possible differences in habitat usage between sexes of nurse sharks off Recife. 相似文献
14.
The hearing thresholds of the nurse shark, Ginglymostoma cirratum, and the yellow stingray, Urobatis jamaicensis, were measured using auditory evoked potentials (AEP). Stimuli were calibrated using a pressure-velocity probe so that the acoustic field could be completely characterized. The results show similar hearing thresholds for both species and similar hearing thresholds to previously measured audiograms for the lemon shark, Negaprion brevirostris, and the horn shark, Heterodontis francisi. All of these audiograms suggest poor hearing abilities, raising questions about field studies showing attraction of sharks to acoustic signals. By extrapolating the particle acceleration thresholds into estimates of their equivalent far-field sound pressure levels, it appears that these sharks cannot likely detect most of the sounds that have attracted sharks in the field. 相似文献
15.
Geographic variation in reproduction between two populations of the bonnethead shark,Sphyrna tiburo 总被引:3,自引:3,他引:0
Glenn R. Parsons 《Environmental Biology of Fishes》1993,38(1-3):25-35
Synopsis A study of two populations of the bonnethead shark,Sphyrna tiburo was conducted in Florida Bay and Tampa Bay, Florida from September 1982 to December 1986. The maintenance of sharks in captivity at the Marine Science and Conservation Center in the Florida Keys, and the collection of sharks from widely separated geographical areas allowed the examination of latitudinal variation in reproduction. Several reproductive parameters were found to differ: (1) size at maturation, (2) age at maturation, (3) time of fertilization, (4) rate of embryonic development, (5) size at birth, (6) the energetic investment in producing offspring, (7) gestation period, and (8) the incidence of infertility. Average litter size and maximum age of females was not different between the two populations. These contrasting life history parameters are not easily explained. Food limitation and seasonal differences between the two areas are considered as factors controlling reproduction in these populations. It is noteworthy that the average size of adult females in Tampa Bay is significantly greater than that of Florida Keys sharks. This size difference may be important in explaining the observed differences in reproduction. 相似文献
16.
LOWER vertebrates such as sharks can synthesize humoral antibodies in response to antigenic stimulation with a wide variety of antigens1. Physicochemical studies have shown that sharks can synthesize both 19S and 7S immunoglobulins and that these two proteins belong to the same immunoglobulin class, which seems to be structurally homologous to IgM as defined for higher animals. Thus the shark immunoglobulins have been designated 19S IgM and 7S IgM2–4. Because the predominant immunoglobulin (IgG) of most mammals is absent from sharks, the shark monomeric (7S) IgM might be functionally analogous to IgG. One example of the functional differences between IgM and IgG antibodies is the greater reactivity of the former in agglutination and bactericidal reactions5,6. We have isolated and characterized functionally the relatively high levels of agglutinating antibodies which the nurse shark, Gingly-mostoma cirratum, synthesizes in response to Salmonella typhimurium “O” antigens. 相似文献
17.
Gregory D. Williams Kelly S. Andrews Deborah A. Farrer Gregory G. Bargmann Phillip S. Levin 《Environmental Biology of Fishes》2011,91(4):379-388
The broadnose sevengill shark (Notorynchus cepedianus) is a high-order marine predator distributed worldwide in shallow coastal waters of temperate seas. Recent reports have suggested
it may be a prevalent component of Pacific Northwest coastal estuarine communities, although biological characteristics of
the shark population remain undocumented despite growing interest in recreational harvest of the species. Longline sampling
was conducted in Willapa Bay and Grays Harbor, Washington, USA seasonally during 2003–2006 to collect sevengill shark size,
maturity, and sex ratio data, and establish some baseline catch rate information. Sevengill sharks were collected on 65% of
longline sets and catches were composed of subadult and mature individuals (122–283 cm TL) of both sexes. Most male sevengill
sharks were large sexually mature adults, based on external clasper calcification levels, whereas most comparably sized females
were considered subadults, based on literature-based size-at–maturity estimates. Neonates and young sharks <120 cm were not
collected, nor have they been reported in other historic estuary sampling efforts. Sex ratios were skewed toward males in
Willapa Bay and suggest some degree of sexual segregation for the species, as has been shown for populations elsewhere. We
suggest sevengill sharks are a largely ignored but potentially important predator in Pacific Northwest estuaries. This study
therefore provides some of the first, basic information for guiding management decisions associated with a late-maturing,
slow-growing shark species in these coastal habitats. 相似文献
18.
Neonatal predation in multispecies aquarium exhibits can prevent detection of captive breeding by wobbegong sharks. We used ultrasonography and isolation strategies to prevent neonatal predation and maximize survival/growth of the dwarf ornate wobbegong (Orectolobus ornatus de Vis, 1883). We captured seven free‐living wobbegongs (two males and five females) and subjected each animal to a health assessment which led to the euthanasia of one female with a retained hook. Ultrasonography showed that females were pregnant, one was preovulatory, and one was in a resting phase. Two females (one pregnant) and one male were placed in isolation in each of two tanks. In October 2006, 25 neonates were born overnight with the two litters placed into separate neonate tanks. Over the ~6.5‐month monitoring period, four neonates with reduced body condition died without premonitory signs resulting in a 63.0% annual survival rate. Finite growth rates did not differ between sexes or litters and averaged (±SE) 12.2 (1.5) cm/year and 156.4 (26.4) g/year. At the cessation of monitoring, total length had increased by ~30%, whereas total weight had almost doubled with neonatal body condition in line with free‐living wobbegongs. Our efficacious, six‐step manipulative, the approach should be applicable with all wobbegongs given their reproductive similarities, but we recommend that efforts focus on the dwarf ornate, tasselled and Japanese wobbegongs because all are small in size and have bred in aquaria. Ultimately, this approach should produce self‐sustaining aquarium populations, place less reliance on the wild acquisition and provide animals for other aquaria, population restocking, or scientific research. 相似文献
19.
David E. Jennings Samuel H. Gruber Bryan R. Franks Steven T. Kessel Anne L. Robertson 《Environmental Biology of Fishes》2008,83(4):369-377
The waters around Bimini (25° 43.70′ N, 79° 18.00′ W) provide an ideal nursery location for juvenile lemon sharks, Negaprion brevirostris, but this habitat is threatened by the development of a large resort. Since 1999 the North Sound (NS) has been subjected
to intermittent periods of dredging, the most intensive of which was in March 2001. Possible effects from the development
up to June 2006 were investigated by: comparing growth rates of juvenile lemon sharks in the NS, Sharkland (SL) and South
Bimini (SB) nurseries between 1995-2005 using before-after, control-impact (BACI) analysis; analyzing survival of juvenile
lemon sharks in the NS and SL between 1995–2006; and by comparing habitat structures in the NS and SB nurseries in 2003 and
2005. BACI analysis detected no statistically significant difference between the growth rates of juvenile lemon sharks in
the three nurseries before and after the impact date of March 2001. However, a reduction in the survival rate of juvenile
lemon sharks in the NS after March 2001 was statistically significant, including a 23.5% decline in first-year survival. Habitat
structure of the NS in 2003 and 2005 also varied with the mean percentage cover of the seagrass Thalassia testudinum declining by 17.7% since 2003. Our results indicate a correlation between the development thus far and a decline in the survival
rates of juvenile lemon sharks and changes in the habitat structure of the NS. To elucidate further information regarding
potential effects of the resort development on juvenile lemon sharks in the NS nursery, we suggest several future research
directions. 相似文献
20.
Jason G. Romine John A. Musick George H. Burgess 《Environmental Biology of Fishes》2009,84(3):277-289
Demographic analyses were conducted for the dusky shark, Carcharhinus obscurus, in the Northwest Atlantic. Fishery-independent, fishery-dependent, and previously published data were used to estimate age
specific by-catch mortality and reproductive cycle for incorporation into the analyses. Correspondence analyses were conducted
for viability (dead or alive), shark length, month, soaktime, and region. Dead sharks were associated with small size, long
soak times, and the spring season, while live sharks were associated with large size and shorter soak times. Data on reproduction
suggested a 3-year reproductive cycle consisting of a 2-year gestation period and a 1-year resting period. Litter sizes ranged
from 3–12 embryos. Decreasing age-specific fishing mortality and a 3-year reproductive cycle were used in age structured life
tables which incorporated stochasticity in life history parameters through Monte Carlo simulation to estimate annual population
growth. Demographic analyses showed that the dusky shark population would decline even at low levels of fishing mortality
despite low natural mortality for neonates. The demographics of this species make it among the most vulnerable to excessive
fishing mortality, and suggest stringent regulatory measures may be required to recover collapsed populations. 相似文献