Alaska Sea Grant
 
Sea Grant Completion Report

Updated 21 June 2001
Project Title: Reproductive Biology of Brown King Crab*
Project Number: R/06-36 Initiation Date: 02/01/97
Revision Date: 11/03/97 Completion Date: 01/31/00
Principal Investigator: A.J. Paul
Affiliation: Institute of Marine Science, SFOS/UAF
Sea Grant Funds: $149,707
Match Funds: $0
Related Projects:  
Parent Projects:  
*Special notes:

The crab taxa examined in this project now has the common name "golden king crab" rather than "brown king crab" that was used when this study was proposed. "Brown king crab" is presently used as the common name for another crab species.

The species name of golden king crab was changed from aequispina to aequispinus during the duration of this project.
Keywords: golden king crab, Lithodes aequispinus,reproduction, molting
1. Objectives:

The overall objective of this proposal was to gain information on growth and reproduction in Lithodes aequispinus to assist regulatory agencies in the management of this species. Specifically, the objectives cited in the proposal that was funded included:

Objective 1. Describe the ability of males of different sizes to breed and successfully fertilize successive females. This objective was completed; see paper below.

Objective 2. Determine the percentage of developing eggs in clutches of females mated to males of different sizes or males bred to several females. This objective was completed; see paper below.

Objective 3. Determine the incubation and fertility periods for females. This objective was completed; see paper below.

Objective 4. Record growth per molt and length of intermolt data for adults of this species. This objective was completed; see paper below.

Opportunistically, information on growth rate and intermolt durations of juveniles 2- 35 mm CL are also included in a paper; see below. This was not an objective stated in the original proposal.

Objective 5. Determine if golden king crab larvae feed and if they exhibit habits similar to benthic or planktonic life styles. This objective was completed; see papers below.

In addition one task was undertaken that was not outlined in the original project objectives. The morphometric characteristics and phylogenetic relationships of the larval and juvenile stages will be described by a paper now in preparation: Paul, J.M., and P. McLaughlin. Abdominal tergite and pleopd changes in Lithodes aequispinus from megalopa to adolescent.
2. Rationale: The golden king crab, Lithodes aequispinus, has supported a commercial harvest worth 10 to 24 million dollars to the fishermen in recent years. Lately, there have been years when golden, rather than red king crab, was the most important crab species harvested in Alaska. Prior to this study, inadequate information was available on the reproductive habits and growth rates of L. aequispinus to draft a solid management strategy. Because this species lives in deep water, typically on un-trawlable bottoms, field studies were not feasible, so a laboratory study was initiated.
3. Methodology: Live observations of reproductive success were utilized to obtain the objectives of the proposal.
4. Benefits:
 The information gained during this study addressed some of the many quandaries associated with the management plan for the species. Reprints of all papers were sent to ADF&G and NMFS crab biologists associated with the NPFMC crab and groundfish management teams. The results from this investigation will be included in the species' biological profile used to craft harvest regulations.
5. Accomplishments:
 This project has been successfully completed. All objectives have been met and the material is either published in peer-reviewed journals or is in review for publication. In addition to completing the original objectives relating to reproduction and growth, additional work on larval behavior and their thermal tolerance was done to enhance our understanding of the recruitment process in this king crab species.
6. Publications and Presentations:

The final report for this project is contained in five published peer reviewed journal papers listed below under the five objectives of the project that they corresponded to. In addition, two more journal papers are in production.

Objective 1:
Paul, A.J., and J.M. Paul. 2001. Size of maturity in male golden king crab, Lithodes aequispinus (Anomura: Lithodidae). Journal of Crustacean Biology 21(2):384-387.

Objective 2:
Paul, A.J., and J.M. Paul. 2001. Size of maturity in male golden king crab, Lithodes aequispinus (Anomura: Lithodidae). Journal of Crustacean Biology 21(2):384-387.

Objective 3:
Paul, A.J., and J.M. Paul. 2001. The reproductive cycle of female golden king crab, Lithodes aequispinus (Anomura: Lithodidae). Journal of Shellfish Research 20(1), in press.

Objective 4:
Paul, A.J., and J.M. Paul. 2000. Changes in chela heights and carapace lengths in male and female golden king crab, Lithodes aequispinus, after molting in the laboratory. Alaska Fishery Research Bulletin 6(2):70-77.

Paul, A.J., and J.M. Paul. In review. Growth of captive juvenile golden king crabs Lithodes aequispinus after molting in the laboratory. Alaska Fishery Research Bulletin.

Objective 5:
Adams, C., and A.J. Paul. 1999. Phototaxis and geotaxis of light-adapted golden king crab zoeae, Lithodes aequispinus (Anomura: Lithodidae), in the laboratory. Journal of Crustacean Biology 19(1):106-110.

Paul, A.J., and J.M. Paul. 1999. Development of golden king crab Lithodes aequispinus (Anomura:Lithodidae) larvae reared at different temperatures. Journal of Crustacean Biology 19(1):42-45.


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