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Marine Resources


November 2013 Issue

Texas Red Drum Shown to be 'Income' Breeder
Every year, the Texas Parks & Wildlife Department spends millions of dollars breeding red drum, a popular game fish, releasing between 20 and 30 million hatchery-raised fingerlings into eight different bays and estuaries along the coast. In order to maximize the numbers that survive to adulthood, the practice has been to provide adult fish a diet rich in fatty acids for nine months before breeding season. During breeding season, to save money and resources, the diet is less rich. University of Texas researchers set out to find evidence that this is an effective practice.

Among fish, 'capital' breeders accumulate and store most of the nutrients they will transfer to their eggs over a long period. For 'income' breeders, the food they eat just before and during the time they spawn is responsible for most of their eggs' nutrient content.

To assess where the red drum falls on this spectrum, Fuiman and Cynthia Faulk, his colleague at the University of Texas Marine Science Institute in Port Aransas, ran experiments varying the content of one particular fatty acid in the diets of red drum during spawning. Then they tested the levels of that fatty acid in the eggs that were spawned during the next few weeks.

If the red drum were capital breeders, such short-term changes in diet should not have mattered much. But there were quick and dramatic shifts in the fatty acid content of the eggs. Within as little as two days of the diet shift, the eggs were showing changes in fatty acid content, with up to threefold increases and decreases in concentration. This meant the immediate diet mattered much more than what the fish had been eating in the months leading up to breeding season.

Fuiman cautioned that the test was for only one of the 14 fatty acids considered essential to egg success. It may be the case that red drum are income breeders with respect to some nutrients and capital breeders with respect to others.

He and his colleagues are in the process of conducting experiments on some of the other fatty acids. They are also planning to conduct year-long tests in which they flip the feeding schedule that state officials have been using.

Protection for Buoy, Sea Lions Developed for WindSentinel
AXYS Technologies Inc. (Sidney, Canada), working in conjunction with Sound & Sea Technology (Lynnwood, Washington), has developed an innovative sea lion protection barrier system for its WindSentinel offshore wind resource assessment system.

The barrier is designed to ensure that seals and sea lions are prevented from climbing onto the WindSentinel during long-term deployments in their habitation areas. It has recently been constructed on the WindSentinel that will be deployed by the United States Navy off the west coast of California.

The sea lions that inhabit the California coastal waters weigh around 300 kilograms on average. The concern when deploying the WindSentinel is to ensure not only the safety of the equipment on deck, but also the safety of the sea lions. The solution developed by Sound & Sea ensures the protection of the system from the sea lions and also allows for ease of access when servicing the system, AXYS said.

The U.S. Navy WindSentinel will be deployed in the fall of 2013 as part of a study to characterize the accuracy of floating lidar systems.

NSU, FAU Win Grant to Study EMF Effect on Marine Life
Nova Southeastern University's (NSU) Oceanographic Center has been awarded part of a $400,000 grant from the U.S. Department of Energy (DOE) that will help fund a project in conjunction with Florida Atlantic University's (FAU) SeaTech facility.

Dr. Richard Spieler, professor and director of academic programs at NSU's Oceanographic Center, and Dr. Manhar Dhanak, director of FAU's SeaTech were awarded the DOE grant to help monitor electromagnetic field (EMF) emissions associated with transmission of power from an offshore energy generating device (i.e., windmill) to an onshore station and measure its effect on marine life.

Dhanak and Spieler's team will collaborate with the Naval Surface Warfare Center Carderock Division's South Florida Ocean Measurement Facility (SFOMF). The observational work will be carried out at SFOMF in Fort Lauderdale, Florida.

The purpose of the project is to monitor and assess how electromagnetic fields generated by an offshore electricity-generating device may affect the behavior of local marine species and seafloor communities. Researchers will monitor EMF emissions from existing cables on the SFOMF range and their impact on marine life using sensors and cameras mounted on an autonomous underwater vehicle, as well as on the seabottom. These existing cables on the seafloor represent typical marine hydrokinetic equipment that may be sited offshore and could affect marine life activity.

NOAA Coast Survey Seeks Comments on Magenta Line
Boaters and others in the maritime community know about problems with the magenta line, which had historically depicted the recommended route for the Intracoastal Waterway. Chart 830, from 1938, shows the magenta line after it was updated by thousands of field workers hired with funds from the Great Depression era's massive Public Works program. NOAA's Coast Survey is weighing several options on whether to keep the magenta line on nautical charts and, if it does, how to improve its accuracy. The office is asking: What is the purpose of the designated route?

Coast Survey wants to hear the views of the people who will be most affected by any decision, so it put a notice in the Federal Register explaining the 104-year history of the Intracoastal Waterway Route, including an update on the current situation.

The office seeks comments that address whether recreational or commercial mariners need a magenta line depicting a specified Intracoastal Waterway Route, and whether that should be a federal government charting responsibility. The public can comment until December 26, 2013.


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