排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
2.
The influence of increased line-fishing mortality on the sex ratio and age of sex reversal of the venus tusk fish 总被引:1,自引:0,他引:1
The age of sex reversal of the venus tusk fish Choerodon venustus , caught by line fishing at various locations on the southern Great Barrier Reef, indicated that C. venustus is capable of modifying its life cycle in response to increased mortality. The evidence suggests Masthead Reef fish, which experience the highest mortality, underwent sex reversal at a smaller size and younger age than at the other sites. The largest female fish, sexually transitional fish and males were smaller at Masthead Reef than at the Swains Reefs or One Tree Reef at Masthead Reef. There was also considerable overlap in the size of males and females within the exploited populations indicating that sex reversal is not initiated at a particular length but may have a social cause. The sex ratio of fish was essentially the same for fish fully susceptible to line fishing in the Swains and Masthead samples. Circumstantial evidence suggested that the absence of large males in a population may initiate sex reversal, indicating the maintenance of a constant sex ratio may have a social basis. 相似文献
3.
Post‐release change of home ranges and diel movement patterns of hatchery‐reared black‐spot tuskfish Choerodon schoenleinii were examined using ultrasonic telemetry. Nine hatchery‐reared C. schoenleinii were released in Urasoko Bay, Ishigaki Island, Okinawa, Japan and monitored using ultrasonic telemetry. The fish gradually increased home ranges for c. 3 months before establishing stable home ranges. This pattern of home‐range change might have been associated with the learning process of natural environments and intraspecific and interspecific competition. The fish also showed strong diurnal movement patterns: moving horizontally and vertically during the day and staying in the same place at night. The behaviour observed in this study is highly valuable to determine when, where and how to release the fish as well as how to increase the fitness of the fish before releasing. 相似文献
4.
We describe how the graphic tuskfish Choerodon graphicus in New Caledonia uses rocks and coral heads as anvils to break open bivalves to obtain food. Video revealed that C. graphicus can make as many as 28 strikes on two anvils over 6 min in a single event. This example of tool use in fishes extends the behaviour taxonomically and geographically and supports the hypothesis that tool use may be widespread in wrasses, particularly those in the Choerodon genus. 相似文献
5.
Kimberley J. Pryor 《Journal of fish biology》2020,97(5):1564-1568
This study investigated tool use by the graphic tuskfish Choerodon graphicus in New Caledonia. Anvils included rocks, a conical shell, flat dead corals and a concrete mooring. Sixteen tool-use events were observed in 10 h. A tool-use event often involved more than one anvil (44%). On average, C. graphicus struck prey six times and spent 84 s at an anvil. The only prey items brought to anvils were bivalve and gastropod molluscs. These results provide a foundation for future research on tool use in fishes. 相似文献
1