Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Sea lion teeth provide window on past

Sea lion teeth provide window on past


A NIWA scientist is drilling the teeth of New Zealand sea lions to learn more about why the species is struggling to survive.

Dr Brittany Graham explains her unique work in the latest edition of NIWA’s flagship publication Water & Atmosphere.

She says sea lion teeth have bands that grow annually, similar to rings in tree trunks.

By taking tiny samples within these bands and then preparing them for stable isotope analysis, Dr Graham aims to find out what the sea lion ate, where it foraged and whether ocean conditions changed over its lifetime.

The New Zealand sea lion was extensively hunted in the 18th and 19th centuries and only about 10,000 remain. In 1997 it was officially declared a threatened species. There are just two main breeding colonies, one at the Auckland Islands and the other at Campbell Island.

However, while the Campbell Island population is faring well, the Auckland Islands’ colony has been declining for a number of years. Several research programmes are under way to find out what factors could be involved in the decline.

Dr Graham’s work enables her to go back through time and use the teeth as an historical library to reveal new layers of information.

“These teeth will provide information not only on whether ocean conditions have changed through time, but also whether there have been changes to the structure of the marine food web.

“In other words, this is a new tool that provides a glimpse at the past 20 years from a sea lion’s perspective.”

The Water & Atmosphere article also explores the work of NIWA’s Dr Jim Roberts, who is developing ways to identify the causes of sea lion decline at the Auckland Islands.

He uses “mark and recapture’ data observed by field teams who record which sea lions have returned to the rookeries. The data also enables scientists to estimate changes in reproductive rates and shifts in age at first pupping.
Also in this issue of Water & Atmosphere, we look at the battle against foreign weeds taking over our lakes and showcase life under the ice at Antarctica in a series of photographs taken when NIWA scientists and specialist divers were conducting experiments in McMurdo Sound over summer.

Ends


© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Tax: GST Threshold For Online Purchases Won't Lower Before 2018

The government wants to lower the threshold on online purchases which qualify for GST from mid-2018, but says more work is needed and there will be no change without public consultation. More>>

ALSO:

North Canterbury: Government Extends Drought Classification

The government has extended a drought classification for the eastern South Island until the end of the year, meaning the area will have officially been in drought for almost two years, the longest period for such a category. More>>

ALSO:

Negotiations Fail: Christchurch Convention Centre Build To Proceed Without PCNZ

After protracted negotiations, the government has ditched the construction consortium it picked to build Christchurch's replacement convention centre, which it now anticipates delivering at least two years behind the original schedule. More>>

ALSO:

Ruataniwha: Greenpeace Launches Legal Challenge Against $1b Dam Plan

Greenpeace NZ is launching a legal challenge against a controversial plan to build a dam that’s set to cost close to $1 billion and will pollute a region’s rivers. More>>

ALSO:

Inequality: Top 10% Of Housholds Have Half Of Total Net Worth

The average New Zealand household was worth $289,000 in the year to June 2015, Statistics New Zealand said today. However wealth was not evenly distributed, with the top 10 percent accounting for around half of total wealth. In contrast, the bottom 40 percent held 3 percent of total wealth. More>>

ALSO:

What Winter? Temperature Records Set For June 20-22

The days around the winter soltice produced a number of notably warm tempertaures. More>>

Conservation Deal: New Kākāpō Recovery Partnership Welcomed

Conservation Minister Maggie Barry says the new kakapo recovery partnership between DOC and Meridian Energy is great news for efforts to save one of New Zealand’s most beloved birds. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news