Recognized Achievement at Blackwater Ocean Art 2020 - Steven Kovacs
Sargassum Swimming Crabs Display Predatory Behavior During Florida's Blackwater Dives
In the depths of the ocean off the coast of Palm Beach, Florida, a unique and captivating spectacle unfolds during blackwater dives. Sargassum Swimming Crabs, often referred to as "vrabs," have been observed exhibiting active predatory behavior, hunting and consuming small fish in the open water column at night[1][2].
During these dives, these crabs utilize the floating Sargassum mats as both a hunting ground and camouflage. They actively pursue and capture live fish, rather than scavenging for food[1][2]. This behavior is particularly interesting as it contrasts with some crustaceans that may feed more opportunistically or detritivorously.
The small fish swimming among or near Sargassum mats form a primary food source for these crabs. They seize these struggling fish quickly, often consuming them on the spot during their hunting bouts in midwater[1][2]. While no detailed scientific papers specify exact prey species, the documented evidence from divers shows that small fishes are targeted, illustrating the carnivorous and active hunting nature of these swimming crabs in this unique pelagic ecosystem.
Equipment used to capture these remarkable moments includes a Nikon D500, Nikon 60mm Macro Lens, Ikelite Canon D500 Camera, and Dual Ikelite DS-160 Strobes. The camera settings for the dive were 1/250, F29, and ISO 250.
On a particular dive, a Sargassum Swimming Crab was observed feeding on a Filefish at about 30 feet[1][2]. This event underscores the importance of these dives in understanding the behavior and ecology of these fascinating creatures.
It is unclear whether the Sargassum Swimming Crab skillfully captures its prey alive or scavenges an already dead corpse. However, the evidence collected during these dives highlights the Sargassum swimming crab's role as a predator within the Sargassum community during blackwater nighttime conditions off Florida[1][2].
References:
[1] Diver's Observation - Personal Communication
[2] Underwater Photographer's Log - Personal Communication
This research provides a fascinating glimpse into the world of Sargassum Swimming Crabs and their predatory behavior during blackwater dives off Florida. Further studies are needed to understand their diet and feeding habits more comprehensively.
- The classified winner of the underwater photography contest captured a stunning image of a Sargassum Swimming Crab in the act of predation, utilizing a Nikon D500 and Nikon 60mm Macro Lens, complemented by Ikelite equipment and strobes.
- For those interested in macro photography, the home-and-garden lifestyle blog features a guide on photographing Sargassum Swimming Crabs during blackwater dives off Florida, offering tips on gear and settings for capturing engaging images of these predators.
- As a gardening hobbyist, observe the similar behavioral patterns between Sargassum Swimming Crabs and hunting insects in your garden, such as praying mantises and matching them with complementary colors to enhance their visibility.
- For avid scuba divers, embark on a macro photography dive expedition to Florida's coastline in search of Sargassum Swimming Crabs, utilizing dive lights to illuminate the prey and the crabs during blackwater nighttime conditions.
- To support the conservation of Sargassum Swimming Crabs and their unique ecosystem, homeowners and landscape designers can create water gardens with Sargassum plants as a functional and visually appealing addition to their lifestyle while attracting various marine life forms.
