Periodic gonadal activity and protracted mating in elasmobranch fishes

Maruska, Karen P.; Cowie, Elizabeth G.; Tricas, Timothy C.

doi:10.1002/(sici)1097-010x(19961015)276:3<219::aid-jez6>3.0.co;2-q

Cited by 103 publications

(124 citation statements)

References 21 publications

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“…Our findings, however, differ from those reported in the spotted ray, Torpedo marmorata, which show no stage-dependency and cell-type specificity of testicular apoptosis (Prisco et al 2003). Since a ZD has also been noted in each testicular lobe of the Atlantic stingray, Dasyatis sabina (Maruska et al 1996), and a ZD and stage-dependent premeiotic apoptosis seen in the little skate, Raja erinacea (L.M. McClusky, unpublished observations), the different mode of testicular apoptosis in Torpedo is difficult to explain other than to suggest the tempering effects of environmental factors peculiar to the Mediterranean sea where this species was studied.…”

Section: Discussioncontrasting

confidence: 99%

Stage and season effects on cell cycle and apoptotic activities of germ cells and Sertoli cells during spermatogenesis in the spiny dogfish (Squalus acanthias)

McClusky¹

2005

Reproduction

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To understand the processes involved in the spatial and temporal maturation of testicular cells in Squalus acanthias, we used standard morphometry, proliferating-cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) immunohistochemistry. Except for immature spermatocysts (germinal zone, GZ; early-stage premeiotic, E-PrM), the number of cysts in all subsequent stages and the total number of cysts in the spermatogenic progression varied seasonally. The spermatogenic cycle spans about 2 years and is interrupted by germcell clone deletion via apoptosis at the mitosis-meiosis transition in April/May, manifesting as a zone of degeneration (ZD). Rate of displacement of the ZD across the testis diameter indicates that late-stage premeiotic (L-PrM) generations 12-13 require 9 -10 months to reach the mature-spermatid stage. Also, the number of cysts completing spermatogenesis is approximately 4-5-fold less than the number that entered spermatogenesis proper 2 years earlier. Pronounced gonocytogenesis in the germinal ridge was coincident with ZD formation in April/May, but it was absent in the fall when mature spermatogonial and meiotic activities had resumed. Whereas strong Sertoli cell PCNA immunoreactivity dominated the GZ cyst cell-cycle activities throughout the year, except during the spring/summer months, the spermatogonial-and Sertoli-cell PCNA indices in E-PrM cysts were inversely related. PCNA immunoreactivity in spermatocytes was seasonal and dependent on the stage of meiosis. TUNEL labelling was limited to spermatogonia and increased stage-dependently in the PrM region (L-PrM 5 mid-stage PrM @ E-PrM @ GZ), correlating with ZD formation, in a season-dependent manner. Results imply that effects of normal regulatory factors in Squalus are stage-and process-specific.

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Section: Discussioncontrasting

confidence: 99%

Stage and season effects on cell cycle and apoptotic activities of germ cells and Sertoli cells during spermatogenesis in the spiny dogfish (Squalus acanthias)

McClusky¹

2005

Reproduction

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“…The sample was dehydrated, embedded in paraffin, sectioned, and stained with hematoxylin and eosin following the protocol of Sulikowski et al (2004Sulikowski et al ( , 2005. Prepared slides were examined to assess spermatogenic development based on the criteria outlined by Maruska et al (1996). Specifically, the mean proportion of the testes that was occupied by mature spermatocysts along a straight-line distance across the medial section of the right testis was determined.…”

Section: Sexual Maturitymentioning

confidence: 99%

Variability in the Reproductive Biology of the Atlantic Sharpnose Shark in the Gulf of Mexico

et al. 2013

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The reproductive biology of the Atlantic Sharpnose Shark Rhizoprionodon terraenovae in the Gulf of Mexico was investigated by examining 1,306 specimens (693 females, 613 males) collected from the Florida Keys to waters off Brownsville, Texas. The results of this study confirm the annual reproductive cycle established for this species; however, there was a significant amount of variability within the cycle. Ovulatory and postovulatory females were present from March to October, indicating that mating and ovulation were occurring over a more protracted period than previously described (e.g., May to July). The occurrence of postpartum females from April to September, the varying sizes of the embryos across several months, and the occurrence of mature spermatozoa in the testes of adults from March to November also corroborate the evidence of reproductive plasticity in this species. This observed variability in the reproductive cycle indicates that the Gulf of Mexico Atlantic Sharpnose Shark population is not completely synchronous in regards to mating, ovulation, and parturition, as a portion of the population is demonstrating reproductive asynchrony. Although the cause of this asynchrony remains unclear, it may be related to the environmental conditions of the Gulf of Mexico, which could provide water temperatures that are optimal for the reproduction of this species through much of the year (i.e., March to October), resulting in a protracted reproductive cycle. Given the results of the current study, the reproductive cycles of other carcharhinid species in this region should be examined in more detail to determine whether there is asynchrony in them as well, as this phenomenon could impact future management strategies.Received October 26, 2012; accepted March 5, 2013

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“…A tissue sample (3-4 mm thick) was removed from preserved testes, placed in cassettes for sectioning and stored in 70% ethanol for transportation. Fixed tissues were further dehydrated in a graded series of ethanol and subsequently embedded in a series of paraffin baths, sectioned to a thickness of 8-10 mm and stained using standard haematoxylin and eosin staining following Maruska et al (1996). Once prepared, the sections were examined under a compound microscope.…”

Section: Histologymentioning

confidence: 99%

“…The stages of spermatogenesis were classified as: stage I, germinal zone; stage II, early spermatocysts; stage III, spermatocytes; stage IV, spermatids; stage V, immature spermatozoa; stage VI, mature spermatocysts; and stage VII, empty spermatocysts (Maruska et al 1996;Ebert et al 2008a). Since the developmental stages of spermatogenesis have been well described for skates, and hormonal analysis has confirmed that spermatocyst and spermatid stages are associated with reproductive readiness (Sulikowski et al 2005(Sulikowski et al , 2006, we concentrated on stages III-VI (Maruska et al 1996). For ease of interpretation, stage VII, consisting of empty spermatocysts and free spermatogonia, was combined with stage VI.…”

Section: Histologymentioning

confidence: 99%

A comparison of reproductive parameters of the Bering skate, Bathyraja interrupta, from two Alaskan large marine ecosystems

Ainsley

Ebert

Cailliet

2011

Mar. Freshwater Res.

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Abstract. Estimates of size at maturity are crucial to fisheries stock assessments and may change spatially and temporally. This study directly compares life-history characteristics of a skate species in two large marine ecosystems in a region where there is both a directed fishery and considerable skate by-catch in other fisheries. The Bering skate, Bathyraja interrupta, is one of the most common skate species in Alaskan waters, occurring in two large marine ecosystems, the eastern Bering Sea (EBS) and the Gulf of Alaska (GOA), but little is known about its life history. Skates were sampled from both regions between 2004 and 2007. In the GOA, the size at maturity was estimated to be 69 cm total length (TL) for males and 71 cm TL for females, while in the EBS size at maturity was estimated as 70 cm and 72 cm TL for males and females, respectively. Median size at maturity differed by sex but not by region. Our results indicate that B. interrupta shows late maturity, typical of most skate species, suggesting that more detailed monitoring of skate populations and precautionary management is warranted as skate fisheries expand.

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Periodic gonadal activity and protracted mating in elasmobranch fishes

Cited by 103 publications

References 21 publications

Stage and season effects on cell cycle and apoptotic activities of germ cells and Sertoli cells during spermatogenesis in the spiny dogfish (Squalus acanthias)

Stage and season effects on cell cycle and apoptotic activities of germ cells and Sertoli cells during spermatogenesis in the spiny dogfish (Squalus acanthias)

Variability in the Reproductive Biology of the Atlantic Sharpnose Shark in the Gulf of Mexico

A comparison of reproductive parameters of the Bering skate, Bathyraja interrupta, from two Alaskan large marine ecosystems

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