Reference | Schweigert, J. and L. Flostrand. 2000. Pacific herring coded wire tagging study: 1999 releases recovered in 2000. Canadian Technical Report of Fisheries and Aquatic Sciences 2335: 33 p. |
Abstract | Midterm results of Pacific herring coded wire tag (CWT) and release program which started in 1999 are discussed in association with one year at large tag recoveries from year 2000 roe fisheries on the BC coast. In March of 1999 approximately 50,000 tags were applied from 16 seine sets in the Strait of Georgia and 5 sets in the Queen Charlotte Islands. Records are presented for 47,712 tag releases in the Strait of Georgia and 6175 tag releases in the Queen Charlotte Islands. Two CWT detectors, each at a different Vancouver processing plant, were used for the first time in 2000 to search roe herring in BC. Approximately 6,700 tons of roe herring were searched by the 2 recovery systems, comprising about 23% of the BC roe herring catch. Sample proportions representing screening efforts for individual herring stock assessment regions were higher for the 3 southern areas (the Strait of Georgia, west coast of Vancouver Island and the Central Coast), ranging from 23.6% to 31.5%, while for the two northern areas (the Prince Rupert District and Queen Charlotte Islands) only about 10% of the catch was searched for CWTs. CWT recovery efforts provided 109 tags that could be related to year 1999 releases and year 2000 capture locations. There were 3 especially notable recoveries from 1999 releases. Two tagged herring released in the Strait of Georgia were recovered in 2000 from Sydney Inlet on the West Coast of Vancouver Island and one of the tagged herring from the Queen Charlotte Islands was recovered in East Higgins Pass in the Central Coast. The remaining 106 herring CWT recoveries from the Strait of Georgia and Queen Charlotte Islands were released and recovered within the same vicinities. The 109 tags recovered in 2000 represent a 1.6% coastwide recovery rate per ton of fish searched whereas the recovery rate per ton of herring harvested was about 0.37%. The relative effectiveness of acquiring recoveries from 1999/2000 efforts was compared with two other herring tag recapture programs and current recovery rates are considered effectively high. Other pertinent topics discussed in the report include fish handling methods and field conditions of tagging efforts and recovering tagged fish. |
Tag | Coded Wire Tag (CWT) |
Objective | Harvest management |