Controlled Rearing of Dungeness Crab Larvae and the Influence of Environmental Conditions on Their Survival, Closing Report November 16, 1965 - June 30, 1971

Identification Information

Citation

Originator: Gaumer, Thomas F.

Publish Date: 1973

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: Cedric.X.Cooney@odfw.oregon.gov

Description

Abstract: It is possible that the large fluctuations in annual Dungeness crab landings are caused by displacement of crab larvae by currents. We studied the effects of various environmental factors on crab larvae survival and behavior. Tests were conducted on cultured zoeae and megalopae and on wild megalopae. Our studies showed that the highest survival (93.3%) of crab larvae through the fifth zoeal stage occurred when they were reared in a closed environment. Newly hatched San Francisco brine shrimp, when fed at concentrations of five per ml of rearing water, were the most satisfactory food source. Optimum larvae densities appeared to be five zoeae per 200 ml of rearing water. All cultured crab megalopae were significantly smaller than those larvae collected from Yaquina Bay. Diet concentration appeared to affect size. Temperature-salinity tests showed that optimum ranges to rear crab larvae are 10.0 to 13.9 C and 25 to 30 0/00, respectively. We were unsuccessful In rearing Tanner crab larvae through the first zoeal stage using handling and rearing techniques developed for Dungeness crab larvae. Postlarval Dungeness crabs exhibited a preference for a sand substrate over a gravel substrate and rejected plexiglass and mud bottoms. Crab larvae displayed variable responses to different light intensities. Generally, the cultured larvae displayed a positive phototactic behavior to low light intensities and a negative response to high light intensities. Cultured Dungeness crab larvae displayed a passive response to current; whereas wild megalopee swam actively in the current chamber. A swimming capability of 62.7 mm per second was observed for the wild megalopae. Although the wild megalopae exhibited a slight positive rheotaxis, there is no evidence that the larvae at sea would display this response. In considering the speed and direction of the ocean currents adjacent to the Pacific coast, it is reasonable to expect larvae to be transported at the mercy of the currents.

Purpose: The attached report may not be correct for this record. It doesn't state the closing report was in "May 1973", however all the other attributes about the record match the attached pdf file. Publication year may have been 1971.

Time Period of Content: November 16, 1965 to June 30, 1971

Geographic Extent: Not Available

Status: Final

Use Constraints:

Format: PDF

Data Quality Information

Lineage-Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Commercial Fisheries Research and Development Act, Subproject 1-5-R, Subproject 1-66-R-1, Contract No. 14-17-0001-2325.

Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description: Field attribute information is available in the attached file(s).

Bibliography Information

Field Name	Value
Biblio ID	1036
Year	1973
Publisher
Request Type	Annual Report
Location	Coast, OR
Date Created
Date Cataloged	2/16/2001 14:21:33
Date Published	1973
Type
Pages	1-43
Volume
Status	0
Descriptor	Dungeness Crab Larvae; Habitat; Harvest; Coast, OR
Date Entered	1/1/1999
Location In Clackamas Library
Author
Duplicates
Number Remaining After Requests
Presumed All Distributed
Back Room Duplicates
Author	Gaumer, T.F.
Risk	Harvest; Habitat
Species
Disposition Of Requests	Tony DAndrea: Requested, but no copies available

Is a physical copy maintained for reference at Headquarters? Unknown