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Marine Resources


May 2013 Issue

California Sea Grant Recognizes New Scientists
Seven research projects have received funding through the California Sea Grant Focus Awards, according to California Sea Grant.

The funding will give opportunities to scientists just starting out at California universities. Six of the recipients are new faculty, starting their positions after 2009.

The projects focus on a variety of topics, ranging from studies of algae, salt marshes and insect parasites to consumer response to green seafood.

Recipients include Christine Cass of Humboldt State University, Kirstin Hardy of California Polytechnic State University, Sindy Tang at Stanford University, Jeremy Long of San Diego State University, Clarissa Anderson at University of California Santa Cruz and Scott Hamilton of Moss Landing Marine Laboratories.

The seventh project that was granted funding explores the socioeconomics of coastal communities.

All of the projects were peer reviewed to determine merit and pertinence to current marine issues.

Acoustic Monitoring Reveals Clues to Cod Behavior
For decades, researchers have recorded sounds from whales and other marine mammals using a variety of methods, including passive acoustic monitoring. For the first time, researchers have used this technology to record spawning cod in the wild.

Few studies have observed cod’s use of sound as part of reproductive behavior. Although both sexes produce low-frequency grunts, only male Atlantic cod make this sound during spawning season.

The research was based on a 2011 pilot study in northern Massachusetts Bay. A single marine autonomous recording unit (MARU) was deployed at a 51-meter depth within a seasonal fishery closure area established to protect a coastal cod spawning aggregation.

Male cod grunts were recorded on 98 percent of the recording days. The grunts, which were most often heard during daylight hours, were most common in late May and early June. The MARU was deployed from April through June 2011.

The next steps for passive acoustic monitoring are to explore the size and extent of known cod aggregations, and to locate other spawning aggregations in the Gulf of Maine and Georges Bank region. Researchers also need to determine if the grunt data can be used to develop an index of relative cod abundance.

Species in more than 100 families of fish are known to produce sounds. The cod family contains several sound-producing species, including haddock, pollock and Atlantic cod.

The study was funded by NOAA’s Ocean Acoustics Program.

Sea Lion Pups Found Ashore, Crowding California Beaches
Southern California shores are becoming crowded as hundreds of sea lion pups are washing up on the beaches, Associated Press reported. Sea lion strandings are significantly higher than in the past, with nearly 400 pups rescued in Los Angeles alone. San Diego, Orange, Santa Barbara and Ventura counties have also seen high numbers of abandoned pups.

Because of overcrowding, shelters have sent pups up the coast to facilities that have more space.

Of the pups born in June, almost half have died. Typically, the statistic is less than one third. Scientists are struggling to understand what NOAA has called an “unusual mortality event.”

Most of the rescued pups have weighed in about 20 pounds less than average. Scientists suspect the pups are swimming to shore, as April is usually when they first leave their mothers.

Scientists believe that a shortage in the sea lions’ food supply, anchovies and sardines, or disease could be behind the overwhelming number of starving pups.

Researchers predict that more sea lions will be found and the trend will continue up the California coast.

High Levels of Nitrogen Found in Upwelling Regions
The upwelling regions of oceans typically have nutrient-filled waters. Microbes in these regions convert nitrogen into other gases, causing scientists to predict low levels of nitrogen fixation.

However, research has found high levels of nitrogen fixation in these areas, according to a study in Geophysical Research Letters.

The study examined the microbes in an upwelling region of the Atlantic near the equator throughout May and June 2009. The results showed that nitrogen fixation was up to seven times higher during upwelling.

The researchers suggest that waters rich in iron but with a low ratio of nitrate to phosphate create a bloom of nondiazotrophic phytoplankton, which remove the nitrate. The microbes will use the leftover iron and phosphate, causing the rate of nitrogen fixation to rise.

The findings could lead to a better understanding of nitrogen and carbon dynamics in upwelling regions.

Overfishing Leads to Genetic Changes
The common practice of removing the largest fish from the population could make smaller, less fertile fish more prominent, according to a paper in Frontiers in Ecology and the Environment.

The paper discusses a lab study that suggests that these changes are occurring at the genetic level. The study modeled a naturally occurring fishing environment and looked at the genetics behind the size of fish.

Smaller size and fewer offspring has increasingly become the trend among fish populations throughout the past century. Scientists have noted the pattern, but have not yet been able to pinpoint the cause.

Two theories have developed to explain the downsize. The harvesting of the largest fish in the population and the animals’ response to a changing environment, like an altered food supply, were both cited as reasons.

Changes in DNA will make it more difficult for fisheries to recover from depleted sources. Harvesting higher numbers of smaller fish could help to mitigate the problem.

The study suggests that commercial fishers will need to consider the evolutionary changes in the fish population if fish are to remain a major source of food.


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