— Archaeologists find new evidence of animals being introduced to prehistoric Caribbean — An archaeological research team from North Carolina State University, the University of Washington and University of Florida has found one of the most diverse collections of prehistoric…
— Microscopic worms could hold the key to living life on Mars — The astrophysicist Stephen Hawking believes that if humanity is to survive we will have up sticks and colonise space. But is the human body up to the challenge?…
— Chemical warfare of stealthy silverfish — A co-evolutionary arms race exists between social insects and their parasites. Army ants (Leptogenys distinguenda) share their nests with several parasites such as beetles, snails and…
— Stinky frogs are a treasure trove of antibiotic substances — Some of the nastiest smelling creatures on Earth have skin that produces the greatest known variety of anti-bacterial substances that hold promise for becoming new weapons in the battle…
— Genetic code of first arachnid cracked — An international team of scientists - including Ghent VIB scientists - has succeeded in deciphering the genome of the spider mite. This is also the first known genome of an arachnid.…
— How bats 'hear' objects in their path — By placing real and virtual objects in the flight paths of bats, scientists at the Universities of Bristol and Munich have shed new light on how echolocation works. Their research is…
— Counting cats: The endangered snow leopards of the Himalayas — The elusive snow leopard (Panthera uncia) lives high in the mountains across Central Asia. Despite potentially living across 12 countries the actual numbers of this beautiful large…
— Surprise role of nuclear structure protein in development — Scientists have long held theories about the importance of proteins called B-type lamins in the process of embryonic stem cells replicating and differentiating into different varieties…
— Pregnancy is a drag for bottlenose dolphins — Lumbering around during the final weeks before delivery is tough for any pregnant mum. Most females adjust their movements to compensate for the extreme physical changes that accompany…
A difficult youth is a good thing for a fish
A tough early life turns out to be a good thing for a fish, according to scientists at the University of California, Santa Barbara.
They discovered that fish larvae that survive a long, rough, offshore journey eventually arrive at a near shore reef in good condition, and that they thrive afterwards.
In contrast, locally produced young have a relatively easy life and they arrive on the reef (near the area where they were spawned) in a variety of conditions - from poor to good. Only the young that are in good condition survive after a month on the reef.
'This research delves into one of the major questions of how populations are connected through dispersal,' said Scott Hamilton, a postdoctoral fellow in the Department of Ecology, Evolution, and Marine Biology (EEMB) at UC Santa Barbara. 'We want to know where the young of many marine organisms are coming from and going to, and what factors determine whether they survive.'
Hamilton is the first author of the report on the team's findings, published in this week's on-line version of the Proceedings of the National Academies of Science (PNAS). The results point to significant policy implications for the planning of marine protected areas, a topic of worldwide concern.
'It turns out that not all settlers arrive equally prepared for the rigours of the reef, and the probability that a new recruit will grow up to reproduce successfully may depend on where it came from,' said Robert Warner, a professor of ecology, evolution, and marine biology.
The scientists used a powerful tool to detect this information: chemical analysis of the ear bone of the fish. The ear bones, also called otoliths, are hard calcium carbonate structures located behind the eyes and below the brain of the fish. The otoliths grow a ring every day from birth, and these rings, like tree rings, hold vast amounts of information about the life of the fish. For example, the spacing of the rings indicates how quickly the fish grew at different periods in its life.
The otolith serves as an internal tag, or tracking device, that reveals the history and location of the fish during its travels. The chemical composition of the ring indicates the type of water in which the fish is located on any particular day.
A fish that is travelling near a populated shoreline collects a higher amount of trace metals, such as lead, in the rings of its otolith. The scientists explain that water near urban areas has higher concentrations of lead due to the run-off from human activities.
Each ocean area has a particular chemical 'signature' or 'fingerprint' that is incorporated into the ring of the otolith as the fish pass through. Thus scientists are able to map the history of the travels of the fish by chemical analysis of the otolith.
The results surprised the scientists. 'This information went against our expectation,' said Hamilton. 'We expected near shore fish to get back and do well, particularly because they are in nutrient-rich waters, which is a good place to be.'
As natural resource managers plan for marine protected areas and marine reserves, they need to know the source of the fish living there.
'We have been measuring 'connectivity' - the proportional contribution of different sources to the population in any particular place - by the numbers arriving,' said Warner. Survival may depend on where the fish originated, he explained.
It is generally agreed that a good knowledge of connectivity between marine populations is critical to spatial management of marine resources, including marine reserves.
The authors point out that connectivity measured by the numbers may be very different from 'realised connectivity,' which is determined in part by differing survival rates of the young recruits.
The fish that the scientists analysed in this study is the bluehead wrasse, a fish that is common in the Caribbean Sea. Warner has studied the bluehead wrasse since the late 1970s.
A third author of the PNAS paper is James Regetz, a programmer and analyst with the National Centre for Ecological Analysis and Synthesis (NCEAS) at UCSB.
Or subscribe for our Newsletter, a free e-mail publication. It is published practically every day.
Scientists find diatom to reduce red tide's toxicity
Foul owls use faeces to show they are in fine feather
Scientists discover new bird species
Rare behind-the-scenes peek at national treasures