Navigation Links
Competition with humans responsible for decline of New Zealand's endangered sea lions, study shows
Date:8/2/2011

221.10.254.64

Marine researchers in New Zealand have identified the direct impact of fishing as the largest known human factor in the decline of the endangered native sea lion population. The team's findings, published in Mammal Review, discount non-human factors, such as disease and identifies resource competition and by-catch incidents as the most likely causes.

The New Zealand sea lion Phocarctos hookeri is the country's only native pinniped species and is listed as 'nationally critical'. The species breeds in the sub-Antarctic, south of New Zealand's mainland, with 71% of the population on the Auckland Islands and the remaining 29% on Campbell Island.

Breeding at the Auckland Islands has declined by 40% since 1998 with only 1501 pups being born in 2009. This decline is directly linked to females not returning to breeding areas. However, while the Auckland Island population has declined, the Campbell Island population appears to be slowly increasing.

Potential reasons for the decline in the Auckland Island population, but not in the Campbell Island colony, include non-human factors such as disease, predation, migration or environmental change. However, possible human factors include population 'overshoot', the effects of contaminants, resource competition and by-catch deaths.

Of the nine potential reasons for the decline of the sea lion population the team discounted six by comparing the Auckland island population with the colony on Campbell Island.

"The most plausible hypotheses based on available evidence is that the decline of breeding females in the Auckland Island population is caused by fisheries-induced resource competition and by-catch incidents" said author Dr Bruce Robertson, from the University of Otago. "Resource competition can lead to nutrient stress and decreased reproductive ability in sea lions and this should be a priority area for future research."

"A fundamental component of assessing and managing any species in decline is the long-term monitoring of changes in numbers and population dynamics in each population of the species," said Robertson. "Both human and natural influences must be taken into account and our study indicates the need for further research and greater conservation management to protect the species."


'/>"/>

Contact: Ben Norman
Lifesciencenews@wiley.com
44-012-437-70375
Wiley-Blackwell
Source:Eurekalert

Related biology news :

1. Evolutionary kings of the hill use good, bad and ugly mutations to speed ahead of competition
2. New study supports Darwins hypothesis on competition between species
3. Competition between females leads to infanticide in some primates
4. Stevens thoracic catheter senior design team takes 1st place at regional ISPE competition
5. Parascript SignatureXpert Wins Forensic Signature Verification Competition
6. Winners announced in 2010 Collegiate Inventors Competition
7. Snap of fruit fly embryo wins scientific photo competition
8. Image of mosquitos heart wins first place in Nikons Small World photomicrography competition
9. Winners of plant-biology video contest announced -- new competition begins at Penn State University
10. Europe ready to launch 3-D TV outperforming the competition
11. Study challenges long-held assumption about competition in disturbed ecosystems
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/21/2016)... Columbia , June 21, 2016 ... to the new role of principal product architect ... named the director of customer development. Both will ... chief technical officer. The moves reflect NuData,s strategic ... in response to high customer demand and customer ...
(Date:6/9/2016)... Paris Police Prefecture and ... ensure the safety of people and operations in several locations ... Teleste, an international technology group specialised in broadband ... its video security solution will be utilised by ... across the country. The system roll-out is scheduled for the ...
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, Biometrics & ... & Other Service  The latest report from ... of the global Border Security market . Visiongain ... billion in 2016. Now: In November 2015 ... and hardware technologies for advanced video surveillance. ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... 2016  Sequenom, Inc. (NASDAQ: SQNM ), ... through the development of innovative products and services, announced ... United States denied its petition to review ... Sequenom,s U.S. Patent No. 6,258,540 (",540 Patent") are not ... the Supreme Court,s Mayo Collaborative Services v. Prometheus Laboratories ...
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf ... join the faculty of the University of North Carolina Kenan-Flagler Business School ... and entrepreneurship at UNC Kenan-Flagler, with a focus on the school’s international efforts, ...
(Date:6/24/2016)... SAN DIEGO , June 24, 2016 /PRNewswire/ ... that more sensitively detects cancers susceptible to PARP ... individual circulating tumor cells (CTCs). The new test ... of HRD-targeted therapeutics in multiple cancer types. ... therapies targeting DNA damage response pathways, including PARP, ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... announce the launch of their brand, UP4™ Probiotics, into Target stores nationwide. The ... is proud to add Target to its list of well-respected retailers. This list ...
Breaking Biology Technology: