Relationships Between Pre-anal Fin Length and Total Length of Roughhead Grenadier (Macrourus berglax Lacepede) in the Northwest Atlantic

摘要

Tail breakage and regeneration in grenadiers has hindered accurate measurement of their total lengths. In 1980, the Scientific Council of the Northwest Atlantic Fisheries Organization (NAFO) adopted anal fin length (from the tip of the snout to the base of the first anal fin ray) as the standardized length measurement for both roundnose and roughhead grenadier. Linear relationships between total length and anal fin length (more properly called pre-anal fin length) are available for roundnose grenadier, but similar relationships for roughhead grenadier in the Northwest Atlantic have not been derived previously. Analysis of data collected in NAFO Div. 2J and 3K in 1978 and 1979 indicate that total length (TL) and pre-anal fin length (AFL) are highly correlated for roughhead grenadier. Unlike in roundnose grenadier, no significant differences were found between the relationships for males and females. The combined relationship is TL = 5.2320 + 2.3455 * AFL