当前位置: X-MOL 学术N. Am. J. Fish. Manag. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Validation of Annuli and Identification of Discontinuities in Sagittal Otoliths of Juvenile Alligator Gar
North American Journal of Fisheries Management ( IF 1.1 ) Pub Date : 2019-09-18 , DOI: 10.1002/nafm.10341
David L. Buckmeier 1 , Nathan G. Smith 1
Affiliation  

Annual increment periodicity has been validated in sagittal otoliths of Alligator Gar Atractosteus spatula; however, discontinuities (often referred to as false annuli or checks) are common in early years, potentially affecting both accuracy and precision. We used up to four injections of oxytetracycline (OTC) to induce time stamps associated with annuli (opaque zones) in the otoliths of juvenile Alligator Gar (ages 2–6; n = 68). These OTC marks allowed us to test a reader's ability to distinguish discontinuities (hereafter, “checks”) from annuli by using established criteria. In addition, the OTC marks were used to infer the timing of translucent zone and opaque zone formation. Although the reader's error rate was low (6%), some checks were essentially indistinguishable from annuli. Checks were common, occurring in over half of the otoliths examined and within all annual increments in these juvenile fish. The association of all OTC marks with the opaque zones of the annual increment further validates annulus formation in juvenile Alligator Gar and indicates that these narrow zones formed approximately between November and June. Subsequently, it can be inferred that the much wider translucent zones formed from about June to November. Although opaque zone formation was complete by June, new annuli were not distinguishable from the ventral edge of the otolith until translucent material was deposited beyond the annuli. In our samples, only 22.2% of the otoliths from fish sacrificed on June 30 (n = 9) had fully visible annuli along the edge of the otolith. Based on multiple studies, it is apparent that annual increments form in the sagittal otoliths of Alligator Gar throughout their lives; however, the interpretation of these increments can be very difficult. In our experience, the OTC marking of fish can provide a valuable tool for training and verification programs needed for this species and for other long‐lived fishes that pose difficulties in age estimation.

中文翻译:

幼年鳄鱼Gar的矢状耳石的瓣环验证和间断点鉴定

年递增周期性已在短吻鳄锅的矢状耳石中得到证实; 但是,中断(通常称为假环或检查)在早期很常见,可能会影响准确性和准确性。我们使用了多达四次的土霉素(OTC)注射来诱导与扬子鳄Gar(2-6岁;n)的耳石中的环空(不透明区域)相关的时间戳。 = 68)。这些OTC标记使我们能够通过使用既定标准来测试读者区分环空(以下称“检查”)的能力。另外,OTC标记用于推断半透明区域和不透明区域形成的时间。尽管读者的错误率很低(6%),但某些检查与瓣环本质上是无法区分的。在这些幼鱼中,检查是常见的,发生在一半以上的耳石中,并且在所有年度增量中。所有OTC标记与年增量的不透明区域的关联进一步验证了幼年扬子鳄Gar中的环空形成,并表明这些狭窄区域大约在11月到6月之间形成。随后,可以推断,从大约六月到十一月形成了更宽的半透明区域。尽管到6月完成了不透明区域的形成,但直到半透明的材料沉积到环空之前,新的环空才与耳石的腹侧边缘区分开。在我们的样本中,6月30日牺牲的鱼耳石中只有22.2%(n  = 9)沿耳石边缘具有完全可见的环空。根据多项研究,很明显,鳄鱼Gar的矢状耳石在其整个生命过程中都以逐年递增的形式出现。但是,这些增量的解释可能非常困难。根据我们的经验,鱼的OTC标记可以为该物种以及对年龄估计造成困难的其他长寿命鱼提供所需的培训和验证计划的有价值的工具。
更新日期:2019-09-18
down
wechat
bug