But less than 1 percent of larvae survive dispersal. They are consumed by predators, encounter harsh environments or never reach their destination and starve. For endangered species, survival of some animals may depend on whether offspring from parents in one protected area can get to another area where they are safe from harvest. "In warmer waters, marine protected areas may need to be closer together than in colder water, since in warmer water dispersal distances tend to be shorter," O'Connor said.
While a one degree increase in temperature at the ocean surface means larvae will travel a shorter distance in warm seas, the effect is more severe when temperatures are below about 59 degrees Fahrenheit (15 degrees Celsius), O'Connor said. Along California's coast, sea surface temperature may warm from 53 degrees to 59 degrees Fahrenheit during an El Nino year, when a warm ocean current appears in the equatorial Pacific Ocean. Larvae that travel 62 miles at 53 degrees Fahrenheit would disperse only 46 miles at 59 degrees.
"On the up side, shorter dispersal can mean greater survival because the larvae spend less time in the water, where they are at a high risk of death. On the down side, it could mean they won't travel as far and may not make it to their juvenile habitat," O'Connor said.
The researchers suspect temperature plays an important role in larval dispersal because metabolic processes in larvae are sensitive to temperature and similar among species. Consequently, larvae in cold waters develop more slowly and drift further before beginning their next development stage because colder temperatures cause sluggish metabolisms.
Source:University of North Carolina at Chapel Hill