[OANNES Foro] Implications of fishing rope strength on the severity of large whale entanglements

[Mario Cabrejos]

Conservation Biology

 <http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1523-1739/accepted>
Accepted Article (Accepted, unedited articles published online and citable.
The final edited and typeset version of record will appear in future.)

DOI: 10.1111/cobi.12590


 


 


Implications of fishing rope strength on the severity of large whale
entanglements

Amy R. Knowlton1, Jooke Robbins2, Scott Landry2, Henry A. McKenna3, Scott D.
Kraus1 and Timothy Werner1,4

1New England Aquarium, Boston, MA, USA 2Center for Coastal Studies,
Provincetown, MA, USA 3Private consultant, Weston, MA, USA 4Department of
Biology, Boston University, Boston, MA, USA. Email: Amy R. Knowlton
(aknowlton en neaq.org)

 


Abstract


Entanglement in fixed fishing gear is a conservation concern for whales
worldwide, including in the United States where deaths of North Atlantic
right and humpback whales have exceeded management limits for decades. We
examined fishing gear removed from live and dead entangled whales along the
US East Coast and the Canadian Maritimes from 1994-2010 to investigate rope
polymer type, breaking strength, and diameter in relation to whale species,
age, and injury severity. For the 132 retrieved ropes from 70 cases, average
tested breaking strength was 2616 lbs (SD 1863; range 180-8910 lbs), which
is 26% lower than strength at manufacture (mean 3530 SD 2224; range
650-12000 lbs). Median rope diameter was 3/8 inch. Right and humpback whales
were found in ropes with significantly stronger breaking strengths at
manufacture than minke whales (4338 3850 and 2353 mean lbs, respectively).
Adult right whales were found in stronger ropes (mean 7664 lbs) than
juvenile right whales (mean 3446 lbs) and all humpback whale age classes
(mean 3906 lbs). For right whales, injuries have become more severe over the
past three decades, possibly due to changes in rope manufacturing in the mid
1990's that resulted in stronger ropes at the same diameter. Our results
suggest that broad adoption of ropes with breaking strengths of 1700 lbs or
less could reduce the number of life-threatening entanglements for large
whales by at least 72%, and still be strong enough to withstand the routine
forces involved in many fishing operations. A reduction of this magnitude
would achieve nearly all of the mitigation legally required for US stocks of
North Atlantic right and humpback whales. Reduced breaking strength ropes
should be developed and tested to determine the feasibility of its use in a
variety of fisheries.

 



---
This email is free from viruses and malware because avast! Antivirus protection is active.
https://www.avast.com/antivirus
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <http://lista.oannes.org.pe/pipermail/oannes-oannes.org.pe/attachments/20150721/a25a40ee/attachment.htm>