scholarly journals Hooked on fishing? Recreational angling interactions with the Critically Endangered grey nurse shark Carcharias taurus in eastern Australia

2013 ◽  
Vol 21 (2) ◽  
pp. 161-170 ◽  
Author(s):  
WD Robbins ◽  
VM Peddemors ◽  
MK Broadhurst ◽  
CA Gray
Keyword(s):  
Critically Endangered ◽  
Nurse Shark ◽  
Recreational Angling ◽  
Eastern Australia ◽  
Carcharias Taurus

scholarly journals Does the grey nurse shark (Carcharias taurus) exhibit agonistic pectoral fin depression? A stereo-video photogrammetric assessment off eastern Australia

2016 ◽  
Vol 22 (1) ◽  
pp. 3
Author(s):  
Kirby R. Smith ◽  
Carol Scarpaci ◽  
Brett M. Louden ◽  
Nicholas M. Otway
Keyword(s):  
Sampling Methods ◽  
Pectoral Fin ◽  
Nurse Shark ◽  
Management Guidelines ◽  
Life History Stages ◽  
Stereo Video ◽  
Eastern Australia ◽  
Wide Range ◽  
Stereo Photogrammetry ◽  
Carcharias Taurus

Underwater stereo-video photogrammetry was used to document the pectoral fin positions of various life-history stages of the critically endangered east Australian population of the grey nurse shark (Carcharias taurus) during normal swimming behaviour at multiple aggregation sites. A wide range in pectoral fin positions was recorded with dihedral pectoral fin angles ranging from –25 to 88°. Pectoral fin angles varied significantly among sites and this was attributed to the differing navigational and energetic requirements of the sharks. There was no significant relationship between pectoral fin angles and distances separating the shark and scuba diver. The wide range in pectoral fin angles, interactive use of the fins during swimming, low-energy behaviours of the sharks at aggregation sites and absence of ‘fight’ response agonistic behaviour indicated that the species does not exhibit agonistic pectoral fin depression. Reports of agonistic pectoral fin depression in the grey nurse shark obtained with visual estimates should be treated as preliminary observations requiring further testing using accurate sampling methods such as stereo photogrammetry. It is important that diver compliance with existing management guidelines that prohibit divers from chasing or harassing grey nurse sharks and blocking cave and gutter entrances is maintained.

Recreational SCUBA diver interactions with the critically endangered Grey Nurse Shark Carcharias taurus

2010 ◽  
Vol 16 (4) ◽  
pp. 261 ◽  
Author(s):  
Sean M. Barker ◽  
Victor M. Peddemors ◽  
Jane E. Williamson
Keyword(s):  
East Coast ◽  
Scuba Diving ◽  
Critically Endangered ◽  
Scuba Diver ◽  
Nurse Shark ◽  
Critical Habitat ◽  
Scuba Divers ◽  
Recreational Scuba ◽  
Large Groups ◽  
Carcharias Taurus

Grey Nurse Sharks Carcharias taurus are listed as ?Critically Endangered? along the east coast of Australia. Magic Point (off Maroubra) in Sydney is favoured by recreational SCUBA divers wishing to observe these sharks. This study was conducted to answer the question: do current recreational SCUBA diving practices at Magic Point have a significant impact on the aggregation behaviour of C. taurus? The study found that diver activity does temporarily affect the behaviour of C. taurus at this site, with a significant difference in the number of sharks and their distribution within the preferred area of occupation inside the cave between diver and non-diver treatments. Small dive groups (= 4 divers) approached the cave closer than large groups, resulting in a greater impact on sharks than large groups positioned further back from the cave. Shark behaviour rapidly returned to pre-diver exposure levels once divers left the area. This study is the first to (a) monitor recreational SCUBA diver activities at a critical habitat site and (b) use a non-invasive behavioural technique to study the behavioural responses of C. taurus towards SCUBA divers in southern NSW. It contributes to improving C. taurus conservation measures along the east coast of Australia by highlighting current diver behaviour and its impact on Grey Nurse Sharks at this site. Results suggest that changes in the current code of practice regarding SCUBA diving at recognized and protected Grey Nurse Shark critical habitat sites should be considered by relevant management agencies.

Multiple paternity in captive grey nurse sharks (Carcharias taurus): implications for the captive breeding of this critically endangered species

2015 ◽  
Vol 21 (2) ◽  
pp. 122
Author(s):  
Robert Townsend ◽  
Adam Stow ◽  
Maria Asmyhr ◽  
Paolo Momigliano
Keyword(s):  
Mating System ◽  
Captive Breeding ◽  
Multiple Paternity ◽  
Paternity Analysis ◽  
Critically Endangered ◽  
Nurse Shark ◽  
Tissue Samples ◽  
Critically Endangered Species ◽  
Eastern Australia ◽  
Nurse Sharks

The grey nurse shark (Carcharius taurus) is listed as threatened throughout much of its global distribution, and as critically endangered in eastern Australia. Captive breeding programs have thus far been largely unsuccessful and little is known of its mating system in this context. Here we carry out a paternity analysis to determine if the mating system in captivity is characterised by multiple mating, and whether poor offspring survival is associated with a particular male. Tissue samples from grey nurse sharks were collected from three potential sires, the two dams and nine pups housed at Manly SEA LIFE Sanctuary in eastern Australia. Each individual was genotyped at seven microsatellite markers and three cases of multiple paternity were inferred. No paternal link to stillborn (5), or scoliotic (2) pups was indicated. For the first time, we show the natural wild phenomenon of multiple paternity occurring in a captive environment.

Impacts of recreational fishing in Australia: historical declines, self-regulation and evidence of an early warning system

2014 ◽  
Vol 41 (4) ◽  
pp. 350-356 ◽  
Author(s):  
MATTHEW A. L. YOUNG ◽  
SIMON FOALE ◽  
DAVID R. BELLWOOD
Keyword(s):  
Early Warning System ◽  
Self Regulation ◽  
Warning System ◽  
Vital Role ◽  
Recreational Fishing ◽  
Recreational Fisheries ◽  
Nurse Shark ◽  
Governance Challenges ◽  
The Impact ◽  
Carcharias Taurus

SUMMARYOverfishing is a mounting threat to marine ecosystems and food security worldwide. Recreational fisheries are poorly understood and pose governance challenges due to the scarcity of monitoring data. The impact of recreational spearfishing on eastern blue groper (Achoerodus viridis) and grey nurse shark (Carcharias taurus) in Australia was analysed by assessing a chronology of spearfishing publications for historical, ecological and social data. Reported captures of blue groper declined by 90% from 1952–1967. Grey nurse shark captures also declined. Interestingly, early warnings of declines for both species emerged from the spearfishing community 17 and 19 years, respectively, before protection. While recreational fishers may have serious impacts on vulnerable fish species, they could also play a vital role in conservation and advocacy. This highlights the importance of reciprocal communication between fishers, scientists and governments for managing and detecting declines in vulnerable species.

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