43: Restored estuaries such as Anaheim Bay may provide females thermal refuge due to the consistently warmer temperatures in the bay compared to surrounding habitat (Mull et al. Additional findings were that round stingrays are slow growing relative to other species in the family Urolophidae.įig. From this study it was found that the population of round stingrays at Seal Beach is composed mostly of sexually mature adults. This information was used in conjunction with size-frequency data from periodic sampling conducted at Seal Beach to determine age structure of the local round stingray population. Growth rate coefficient (K) and theoretical maximum disc width (WD) were estimated using the von Bertalanffy growth model. Estimates of age were determined by analysing the vertebral growth rings of round stingrays (U. Hale and Lowe 2008 conducted a growth and age structure study of the round stingray (U. Vaudo and Lowe 2006 found that round stingrays seasonally congregate for a few weeks at Seal Beach before dispersing to other locations in search of suitable breeding grounds. 37: Round stingray movement was greatest at night during the ebbing (falling) tide when water temperature is increased, likely to find more desirable conditions, increase foraging success, or find potential mates. Therefore, the best defense against stingray related injuries is to remember to shuffle your feet and to educate beach visitors about the local wildlife they may come into close contact with during their visit.įig. Given the size of the population and the amount of new stingrays that can be found in the area, particularly during the summer/fall months when stingray abundance is at its peak, a stingray spine clipping program was deemed impractical and unrealistic to implement. Table 1: Preliminary results of mark and recapture analysis estimates the population of round stingrays at Seal Beach is nearly 16,000 rays Dateįollow up mark and recapture studies at Seal Beach reported low recapture rates despite a high sampling effort, indicating that the round stingray population in Seal Beach is very mobile with a high turnover rate (Vaudo and Lowe 2006, Lowe et al. After which each ray was measured, weighed and marked with an ID tag for later recapture.
30: Once captured we measured the length of the primary and secondary spine (if present), then clipped the spines near the base. Juvenile White Shark Behavior and Biologyįig.Contaminants in Urban Green Sea Turtles.Fish Behavior and Offshore Oil Platforms.Fish Movements and Marine Protected Areas.
Respirometry and Bioenergetics of Gamefishes, Sharks and Rays.
0 kommentar(er)
