Dataset: herring spawng grounds_ctd
Deployment: NEC-JA2005-2

Herring play a key role in New England's fishing economy. Robust offshore herring abundance on Georges Bank offers a hopeful example of a fishery's potential to recover from commercial extinction. Yet the coastal herring spawning stock is thought to be in danger of depletion. Efforts to manage the coastal stock are hindered by the absence of independent information on abundance. Hydroacoustic survey techniques, which are widely employed in other countries, present a possible solution to this problem. The Gulf of Maine Aquarium Development Corporation (ADC) has recently tested an innovative, industry-based acoustic survey approach. Industry vessels have proven to be a cost-effective survey platform that may be superior to traditional research vessels for both shallow-water operations and the fish sampling that is a necessary component of acoustic surveys. The only problem during the pilot phase of this project has been that market pressures preclude commercial herring vessels from devoting sufficient time (circa 30 days) to completely survey the coastal stock during the narrow time window immediately prior to spawning. Our proposed solution is to utilize the acoustic survey capabilities of a groundfishing vessel. A scientific-grade, multiple-frequency echosounder and data logging system will allow that vessel to collect high-quality acoustic data. An acoustic net positioning system will make it possible to effectively deployed position a mid-water trawl for herring sampling. In addition, a CTD with a fluorometer will permit us to simultaneously sample hydrographic variables that may be used to predict herring distributions (and hence target future acoustic survey efforts). We will use a parallel transect design to survey pre-spawning herring aggregations along the Maine coast as they assemble from northeast to southwest during the late summer and autumn spawning season. Fish samples will be collected to determine species composition and permit accurate conversions between acoustic backscatter and herring biomass.

<p>Herring play a key role in New England's fishing economy. Robust offshore herring abundance on Georges Bank offers a hopeful example of a fishery's potential to recover from commercial extinction. Yet the coastal herring spawning stock is thought to be in danger of depletion. Efforts to manage the coastal stock are hindered by the absence of independent information on abundance. Hydroacoustic survey techniques, which are widely employed in other countries, present a possible solution to this problem. The Gulf of Maine Aquarium Development Corporation (ADC) has recently tested an innovative, industry-based acoustic survey approach. Industry vessels have proven to be a cost-effective survey platform that may be superior to traditional research vessels for both shallow-water operations and the fish sampling that is a necessary component of acoustic surveys. The only problem during the pilot phase of this project has been that market pressures preclude commercial herring vessels from devoting sufficient time (circa 30 days) to completely survey the coastal stock during the narrow time window immediately prior to spawning. Our proposed solution is to utilize the acoustic survey capabilities of a groundfishing vessel. A scientific-grade, multiple-frequency echosounder and data logging system will allow that vessel to collect high-quality acoustic data. An acoustic net positioning system will make it possible to effectively deployed position a mid-water trawl for herring sampling. In addition, a CTD with a fluorometer will permit us to simultaneously sample hydrographic variables that may be used to predict herring distributions (and hence target future acoustic survey efforts). We will use a parallel transect design to survey pre-spawning herring aggregations along the Maine coast as they assemble from northeast to southwest during the late summer and autumn spawning season. Fish samples will be collected to determine species composition and permit accurate conversions between acoustic backscatter and herring biomass.</p>