Age Structure Differences in American Mink , Mustela vison , Populations under Varying Harvest Regimes
Two American Mink populations were examined using canine tooth cementum annuli to assess age structure of harvested segments of the populations. Trapping mortality was different between these two populations. Comparisons are made with a Montana Mink population. I propose that forbearer managers can readily assess relative harvest pressures by analyzing the age structure of a Mink population, and offer management recommendations for populations displaying various age structures.
Home Ranges and Movements of the Mink Mustela vison Shreber in Southern Sweden
Home ranges of nine minks Mustela vison in southern Sweden were studied by telemetric techniques during eleven periods in 1968-69. Data obtained allowed accurate determinations of the boundaries of the ranges and quantitative descriptions of the distribution of use-intensity. Information on seasonal movements were obtained by trapping and marking. The adult male occupied the largest home range, twice as large as that of the juvenile male. Adult females kept within smaller ranges than the adult males. In winter the minks tended to concentrate their activity to restricted parts of the home ranges. The great irregularity found in intensity of use of the home range may be due to the availability of food. An adult female may temporarily hold a territory against an adult male. The balance, however, demands more attention from her at the common border. Unlike juvenile females, juvenile males did not seem to be allowed to stay within the ranges of adult males. The dispersal of juveniles started in the beginning of July and most of them left the study area. The extent of male movements during the mating season was greater than during the rest of the year.
Morpho-biometric Relationship, Relative Condition Factor and Meat Yield of Distant Scallop Bractechlamys vexillum (Reeve, 1853) in Asid Gulf, Philippines
Understanding the relationships of morphometric and biometric characters of a species allows the prediction of one trait from the other and generate a measure of relative condition. These relationships were studied for the Distant scallop Bratechlamys vexillum (Reeve, 1853) in Asid Gulf. Representative samples collected during the dry season (May 2018, n = 99) and wet season (September 2018, n = 100) were used to analyse these relationships through models of simple linear and power regression analyses, revealing allometric growth patterns. For both periods, it was revealed that shell width (SW) is a slightly better predictor than the height (SH) for total weight (TW) (R2 = 0.90 and 0.92) and the adductor muscle weight (AW) (R2 = 0.78 and 0.80). The strong functional relationship was also observed between TW and AW (R2 = 0.80 and 0.81). The relative condition factors (Kn) were high in both seasons. High meat yields were also observed in May (12.77 %) and September (14.26 %). The significant difference in meat yields (P < 0.05) can be a result of the seasonal difference manifested by the dynamics of energy partitioning during gametogenesis and spawning. These biological metrics are vital inputs in analysing mariculture prospects for the resource and a contribution to the scarce information on the biology of the species.