by
Rebecca Sherratt, Features Editor, International Aquafeed
The Lemon shark (Negaprion brevirostris) is a species belonging to the
Carcharhinidae family which can be found in the Western Atlantic Ocean and
South-eastern Atlantic. Individuals familiar with farming fish in subtropical
waters may be aware of the Lemon shark and its status as a particularly
dangerous predator. Lemon sharks have an especially varied diet but a
particular fondness for bony fish, crustaceans and shrimp.
In the US especially, Lemon sharks are often caught as bycatch in both gillnet
and pelagic fisheries. Their name derives from their yellowish hue, which
enables the Lemon shark to blend in with the sandy seafloor and remain
undetected by the fish above. The species can also be recognised by their blunt
snout, which is shorter than the width of their mouth and notably more rounded
than those of other shark species. Lemon sharks lack a mid-dorsal ridge and
their two dorsal fins are remarkably similar in size.
Lemon sharks can grow up to 11.3ft long and 183kg and tend to inhabit the
shallow waters of mangroves, coral reefs and enclosed bays, which also serve as
nursery areas for the smaller fish they prey upon. They rarely enter open
waters any deeper than 300 feet, aside from during migrations, preferring
continental and insular shelves for their hunting.
This species of shark prefers to live in groups. Known to be social creatures,
they regularly communicate for courtship and protection purposes. Feeding is
rarely a solitary activity and, once prey is secured, Lemon sharks will feed en
masse. Lemon sharks reach sexual maturity at approximately 12-16 years of age
and give birth to pups in shallow nursery waters which they often return to
throughout their lives.
Hunting methods
The belief that sharks are opportunistic hunters is especially true for Lemon
sharks. This species will typically relocate to wherever there is prey in
abundance and will feed on whatever is available at the time such as catfish,
jacks, croakers, crayfish, stingrays and mullet. Despite this, many studies
have shown evidence to suggest that Lemon sharks also display preference
towards certain species and will actively avoid preying upon certain species in
favour of others.
The Lemon shark will adopt a stalking technique to hunt slower species that are
easy to capture. In the Bahamas, the Lemon shark’s primary diet will consist of
mojarras, a species which notably camouflages in an attempt to escape a
threatening situation, rather than to simply swim away.
Lemon sharks feed at night through the use of electroreceptors to detect the
movement of their prey in twilight waters. Unlike other shark species, which
rip their prey apart upon initial contact, Lemon sharks swim up to their prey
at impressive speeds, only to brake abruptly and jab the prey with their
pectoral fins. Once the Lemon shark has disorientated their prey, they clamp
down with their jaw and shake their heads from side to side until chunks of
flesh are torn off.
Read more, HERE.
The Aquaculturists
No comments:
Post a Comment