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Fish MARINE RESOURCES
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2005 Research Projects

The following is a partial list of MRP research objectives and projects in progress in 2005:

 Objective: Evaluate discard as a management tool for Pacific rockfishes.

Barotrauma Studies

A number of projects are underway to evaluate how barotrauma in captured rockfish influences survival upon release. These studies include laboratory survival studies using pressurized aquaria, field studies using underwater video to observe fish behavior upon release, mark-recpature studies to evaluate the effectiveness of venting excess swimbladder gas and acoustic telemetry studies of released rockfish to try to measure longer term survival.


Pressure Tanks


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Pressure Tanks

This hyperbaric aquarium system was constructed at the Hatfield Marine Science Center in Newport and used to estimate survival rates of black rockfish recompressed after capture (released at depth) and to learn about their swimbladder acclimation rates when changing depths.


Yelloweye Release


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Yelloweye Release

When rockfish are captured in deep water (>100ft), symptoms appear immediately lethal. However, if recompressed, immediate symptoms appear to resolve and many fish swim away. Long term survival for these fish is not known.

Click on the picture for a video (3.4 mb) showing a recreationally caught yelloweye rockfish being placed in a cage and lowered to approximately 70 feet before being released. Note the gut protruding from the mouth, the bloated body, and general disorientation the fish displays at the surface. Upon descent, the gut retracts, and the fish shows good orientation before swimming strngly downward. Windows Media Player required to view.


Venting


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Venting

Some fishers are venting fish prior to surface release. The effectiveness of this technique is not known, so we are conducting a mark-recapture study with black rockfish to measure any significant effect on survival.

To estimate longer-term survival, we are also working on a project to acoustically tag yelloweye rockfish following hook and line capture, release them using recompression techniques, and then track them with acoustic receivers and an ROV to evaluate condition after several weeks.

Objective: Develop new tools for managing nearshore rockfish.

 Black Rockfish PIT Tagging

This is long-term project to evaluate if PIT tags (Passive Integrated Transponder) can be used effectively to estimate exploitation rates of black rockfish. We charter CPFV vessels, tag several thousand fish each spring and search for recovered fish at the docks. Data are used in a population estimation model to determine exploitation rate and population size each year.

Bob's Cage

Bob's Cage


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Cages

A cage is used to take the fish down to a depth of 50 feet before release. The rope is pulled causing resistance on a paddle which opens the hinged end of the trap. Above are two examples of different types of release cages. The cage on the left opens from the bottom via the large paddle. The cage on the right opens like a suitcase via the metal plate on the left side. For information on constructing a release cage, please contact the Newport Marine Resources Program.

Parker's Cage

Parker's Cage


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Black Rockfish Movements

This is a "support study" for the PIT tagging project that uses acoustic telemetry techniques to measure the home range and movements of black rockfish to determine if the assumptions of a PIT tagging program are met (e.g. minimal emigration from the study area). Results of this study will also be useful in describing essential fish habitat, seasonal use of space, and efficacy of marine protected areas for species such as black rockfish off the Oregon coast.

Acoustic Receiver and tag

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Acoustic Receiver and tag

Picture shows an acoustic tag in the person's hand and the associated receiver.

 Objective: Reduce fishery bycatch.

Testing a 3/4 inch BRD in the Shrimp Fishery

This project tests the use of reduced bar spacing in a BRD (Bycatch Reduction Device) in the pink shrimp trawl fishery to reduce the bycatch of small flatfish and juvenile rockfish.

Halibut Escape

Click on the picture for a video (1.2 mb)

Halibut Escape

A video showing a view of a finfish excluder in a shrimp trawl, with a Pacific halibut exiting the net.

Windows Media Player required to view.

Testing a DIDSON Imaging Sonar in Trawl Nets

This project evaluates the utility of an imaging sonar to observe fish behavior in and around trawl nets in the absence of artificial light. We can use this tool to evaluate how fish respond in an approaching trawl in areas with little or no visible light, and design bycatch reduction methods for those species that show different behaviors.

Didson Sensor

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Didson Sensor

The Didson sensor is shown below the person on the right in a protective housing that is attached to the trawl net.

Objective: Improve data for stock assessments.

 Improved Maturity Data

This project conducts expanded maturity sampling for female fish of selected species that currently lack adequate data for Oregon populations. The project also utilizes histological evaluation of ovarian sections to expand the useful sampling window for maturity data. We are currently working on several species of nearshore and slope rockfish, along with cabezon and kelp greenling.

 Other Recent Projects

Development of a Selective Flatfish Trawl

This multi-year project developed, in collaboration with the fishing industry, a selective flatfish trawl that decreased the bycatch of many rockfish species. The trawl incorporates a low-rise design and a cut-back "hood" or "square" that facilitates the escapement of fishes that rise when encountering a trawl, such as canary rockfish and Pacific halibut. For more information on the selective flatfish trawl, click on the "Publications" tab at the top of this page.

Selective Flatfish Trawl

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Selective Flatfish Trawl

A picture of the selective flatfish trawl at the HMSC Seafest, June 2004. Note the size in relation to the people and automobiles.

Evaluation of ROVs as Passive Survey Tools

ROVs are being utilized more and more for surveying fish populations in untrawlable areas and have several benefits over traditional trawl surveys. However, because they are slow and depend on visual identification of each species, work needs to be done to determine if different species are repelled or attracted by the presence of the ROV, its lights, sounds, smells etc… We conducted a project to film fish behavior behind an ROV during survey transects to test the hypothesis that fish behave the same as the ROV approaches and as it goes past (ie, it is a passive observer).

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