ANAMAR News

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Aug
22

Exciting New Research on the Largetooth Sawfish Reveals the True Range of this Enigmatic Species in the United States

Well ahead of International Sawfish Day (October 17) is this concise paper that Jason, and his colleague John Waters, recently published in Gulf and Caribbean Research on the largetooth sawfish (Pristis pristis).  Sawfishes have been in the scientific spotlight for several years now, as populations in many areas are reduced and in need of conservation and research.  Jason and his coauthor attempt to clarify and correct some of the misleading information about the U.S. range of this enigmatic saw-snouted shark-like beasty.  Hopefully, this species will be found to still occur in Texas waters, such as by environmental DNA survey techniques.  If and when this occurs, critical habitat can be designated following implementing regulations 50 CFR § 424.12, provision 5(f). Click here for the PDF: Ppristis-range-in-the-U.S-Seitz-and-Waters-2018

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Seitz, J.C. and J.D. Waters.  2018.  Clarifying the range of the endangered largetooth sawfish in the United States.  Gulf and Caribbean Research 29:15–22.

 

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Apr
24

ANAMAR Senior Biologist Teams with Other Fish Experts in Producing the First Estimates of Age and Growth in Wild Southern Stingrays (Hypanus americanus)

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A 2018 study published in the peer-reviewed journal Gulf and Caribbean Research represents a collaborative effort between ANAMAR biologist Jason Seitz and colleagues at the University of New England and the Florida Fish and Wildlife Research Institute.  Southern stingrays (Hypanus americanus, previously Dasyatis americana) were sampled and measured at fishing tournaments from 2004 and 2012 in Charlotte Harbor, Florida.  Vertebral centra obtained from the stingrays were sectioned and mounted on slides, and their growth bands were counted by two independent readers.  A total of 18 female southern stingrays, measuring from 412 to 1127 mm disc width (DW) were aged.  Ages ranged from 0 to 17 years.  The results suggest that southern stingrays obtain relatively old ages (17 years) and large sizes (to at least 1127 mm DW).  The results are comparable to other large stingray species such as the brown stingray (Bathytoshia lata; to at least 24 years and 1790 mm DW) and the common stingray (Dasyatis pastinaca; to at least 16 years and 1140 mm DW).  The results are also comparable to size-at-width data from a captive population of southern stingrays (13 years for a 1000-mm DW captive female, compared to an estimated 12 years for a 1005-mm DW wild female in this study).  The age-at-width estimates given in the 2018 study provide a preliminary foundation for future studies on age and growth of southern stingrays for the generation of mortality rates, production rates, and growth models, such as a Von Bertalanffy growth function or a Gompertz function, once ages of each life stage are obtained.  This study is the first investigation of the age-at-widths of wild southern stingrays. 

Here is a link to the open-access paper: Southern-stingray-age-and-growth-FINAL-2018

Source

Hayne, A.H.P., G.R. Poulakis, J.C. Seitz, and J.A. Sulikowski.  2018.  Preliminary age estimates for female Southern Stingrays (Hypanus americanus) from southwestern Florida, USA.  Gulf and Caribbean Research 29:SC1–4.  DOI:10.18785/gcr.2901.03  

 

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