Every year, Reef Check trains thousands of citizen scientist divers who volunteer to survey the health of coral reefs around the world, and rocky reef ecosystems along the entire coast of California. The results are used to improve the management of these critically important natural resources. Reef Check programs provide ecologically sound and economically sustainable solutions to save reefs, by creating partnerships among community volunteers, government agencies, businesses, universities and other nonprofits.
Sandbar shark (C. plumbeus): The sandbar shark has a snout that is shorter than the width of its mouth and a large first dorsal fin originating over the axis of the pectoral fin (the Caribbean reef shark’s first dorsal fin is further from the head than the sandbar shark). Unlike the Caribbean reef shark, the sandbar shark has widely spaced non-overlapping dermal denticles that lack defined teeth on their free edges.
The Caribbean reef shark (Carcharhinus perezi) is a species of requiem shark, belonging to the family Carcharhinidae. It is found in the tropical waters of the western Atlantic Ocean from Florida to Brazil, and is the most commonly encountered reef shark in the Caribbean Sea. With a robust, streamlined body typical of the requiem sharks, this species is difficult to tell apart from other large members of its family such as the dusky shark (C. obscurus) and the silky shark (C. falciformis). Distinguishing characteristics include dusky-colored fins without prominent markings, a short free rear tip on the second dorsal fin, and tooth shape and number.
There is little evidence of territoriality in the grey reef shark; individuals will tolerate others of their species entering and feeding within their home ranges. Off Hawaii, individuals may stay around the same part of the reef for up to three years, while at Rangiroa, they regularly shift their locations by up to 15 km (9.3 mi). Individual grey reef sharks at Enewetak become highly aggressive at specific locations, suggesting they may exhibit dominant behavior over other sharks in their home areas.
Social aggregation is well documented in grey reef sharks. In the northwestern Hawaiian Islands, large numbers of pregnant adult females have been observed slowly swimming in circles in shallow water, occasionally exposing their dorsal fins or backs. These groups last from 11:00 to 15:00, corresponding to peak daylight hours. Similarly, at Sand Island off Johnston Atoll, females form aggregations in shallow water from March to June. The number of sharks per group differs from year to year. Each day, the sharks begin arriving at the aggregation area at 09:00, reaching a peak in numbers during the hottest part of the day in the afternoon, and dispersing by 19:00. Individual sharks return to the aggregation site every one to six days. These female sharks are speculated to be taking advantage of the warmer water to speed their growth or that of their embryos. The shallow waters may also enable them to avoid unwanted attention by males.
Off Enewetak, grey reef sharks exhibit different social behaviors on different parts of the reef. Sharks tend to be solitary on shallower reefs and pinnacles. Near reef drop-offs, loose aggregations of five to 20 sharks form in the morning and grow in number throughout the day before dispersing at night. In level areas, sharks form polarized schools (all swimming in the same direction) of around 30 individuals near the sea bottom, arranging themselves parallel to each other or slowly swimming in circles. Most individuals within polarized schools are females, and the formation of these schools has been theorized to relate to mating or pupping.
This sturdy shark is abundant in the Caribbean, and because of its average features, is often confused with other requiem sharks. Usually growing 6.5 to 10 feet long, these are the apex predator of their food web. They have been found ‘sleeping’ in caves and on the ocean floor, behavior that is still unexplained. There has been concern over eating these sharks because of the build-up of toxins in their flesh, but now they are valued for tourism more than food, which brings its own safety issues.
Grey reef sharks are often curious about divers when they first enter the water and may approach quite closely, though they lose interest on repeat dives. They can become dangerous in the presence of food, and tend to be more aggressive if encountered in open water rather than on the reef. There have been several known attacks on spearfishers, possibly by mistake, when the shark struck at the speared fish close to the diver. This species will also attack if pursued or cornered, and divers should immediately retreat (slowly and always facing the shark) if it begins to perform a threat display. Photographing the display should not be attempted, as the flash from a camera is known to have incited at least one attack. Although of modest size, they are capable of inflicting significant damage: during one study of the threat display, a grey reef shark attacked the researchers' submersible multiple times, leaving tooth marks in the plastic windows and biting off one of the propellers. The shark consistently launched its attacks from a distance of 6 m (20 ft), which it was able to cover in a third of a second. As of 2008, the International Shark Attack File listed seven unprovoked and six provoked attacks (none of them fatal) attributable to this species.
Reef Industries, Inc. is delighted to announce that November 2017 will mark the celebration of its 60th year in business. Founded in November 1957 by the late William D. Cameron, Reef Industries, Inc. was built on the foundation of being a reliable source of custom plastic laminate needs for our customers. Over the years, new technologies and innovations produced a variety of manufacturing techniques ultimately developing a wide range of products and material grades. With the introduction of these new product lines, the corporate identity of Reef Industries, Inc. was adopted in 1976. There is no time more fitting than now to thank our valued customers for their loyalty and support.
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Reef Dispensaries provides a wide selection of quality cannabis at every price point in Nevada and Arizona. Southern Nevada residents and visitors can stop in at our Las Vegas Strip or North Las Vegas recreational/medical destinations, while those in Reno can shop our Sparks and Sun Valley recreational/medical locales. Arizona medical patients can attend our original Queen Creek and brand new Central Phoenix locations. Come experience Reef’s concierge customer service and curated product selection today. [Our Nevada locations accept out-of-state medical cards with government issued ID (from outside Nevada) or passport.]