Though some people have a little familiarity with Pacific Sharpnose Sharks (family Carcharhinidae), these Requiem Shark relatives are still often overlooked in terms of their importance to marine ecosystems. They may be smaller than other well-recognised shark species, such as the large oceanic or coastal-dwelling tiger sharks and great whites; however, their slender shape, pointed snout, and active foraging behaviours also make them interesting predators. Unlike several of the very large shark species that attract the most public attention for their enormous size and ferocity, Pacific sharpnose sharks spend much of their time silently patrolling shallow-water areas along tropical and temperate coastlines; this enables them to help regulate prey populations by eating fish, squid, and crustaceans.

Pacific Sharpnose Sharks (Rhizoprionodon longurio) are members of the Requiem Shark Family (Carcharhinidae). These sharks can be easily identified by their elongated, pointed snouts, slender bodies, and rapid swimming capabilities. While they may be somewhat overshadowed by larger predators such as Tiger Sharks and Great White Sharks, Pacific Sharpnose Sharks have a very high success rate in feeding on other animals in shallow coastal areas. The majority of their time is spent foraging in shallow water along coastlines, bays, estuaries, and continental shelves.

Pacific Sharpnose Sharks are found exclusively in the Eastern Pacific Ocean. From Southern California to Peru is where you can find them. Generally, these sharks live at depths of less than 100 meters; however, there have been documented cases of them travelling farther out into open waters.

These animals prefer living in shallow areas such as:

• Sandy coastlines
• Bays
• Estuaries
• Continental Shelves

This shark prefers warmer temperatures because it does not do well in cold water.

The Pacific Sharpnose Shark is distinguished by several features that set it apart from other species with similar morphological traits.

Distinctive Identification Characteristics

• Pointed, long, slender snout
• Large black eyes
• Streamlined, thin body
• Upper portion of grey-brown colouration
• White belly
• Moderate-sized first dorsal fin (with a tiny second dorsal fin located far back near the tail
• Lack of noticeable markings on the fins
• Adapted sliver-like teeth for capturing fast-moving soft-bodied prey

Their slender bodies enable the sharks to make rapid, short sprints in pursuit of their primary food source: small schooling fish.

Pacific Sharpnose Sharks (Rhizoprionodon longurio) are relatively small compared to most shark species.

The average body lengths for this species include:

• The average birth length of the young is about 30-35 cm
• Young of this species reach an average of approximately 60-90 cm
• Adult individuals reach an average of approximately 1.1-1.3 meters
• This species can be up to 1.5 m long.

On average, females tend to grow slightly longer than males, as in many Requiem Shark species. Because of their smaller stature, they will likely do well in densely populated coastal habitats where agility is far more valuable than raw power.

Pacific Sharpnose Sharks are opportunistic feeders (carnivorous), and their diet is dynamic in terms of changing as they grow older and based on available food sources. The most common foods eaten by this species include:

• Sardines
• Anchovy
• Herring
• Mackerel
• Squid
• Octopus
• Shrimp
• Crab
• Various small Crustaceans

Newly hatched young tend to eat a variety of crustaceans, whereas adults typically feed on schooling fish and cephalopods. Their pointed snout enables quick detection and capture of highly mobile prey.

Pacific Sharpnose sharks are viviparous. That is, instead of laying eggs like most other fish species, they have their babies internally (fertilised) and then deliver them alive (as pups).

Reproductive Characteristics:

• Internal Fertilisation
• Live Birth
• Gestation time varies by about 10–12 months
• Litters vary in number, with an average of 3–11 pups
• Pups are self-sufficient when born

Most females will utilise these shallow nursery areas on the coast, as they provide some degree of safety from large predators attracted by the presence of juveniles.

Scientists estimate that a Pacific Sharpnose Shark will survive for approximately 10 to 20 years. As with most other shark species, the Pacific Sharpnose Shark grows relatively quickly in its early years, then slows as it reaches adulthood.

The Pacific Sharpnose Sharks are similar to other types of sharks when it comes to:

• Reaching sexual maturity at an older age than many species of bony fish
• Producing fewer offspring per year than many species of bony fish
• Spending more time and resources on reproduction

This makes shark populations take longer to recover from large-scale commercial fishing activities.

Pacific sharpnose sharks play a significant role as “mid-water” predators in their ecosystems. They help maintain marine ecosystem health by controlling the populations of many smaller fish and invertebrate species.

A stable shark population is vital for the functioning of:

• Balancing the marine food web
• Maintaining stable fish populations
• The Health of Coastal Marine Ecosystems
• Increasing Biodiversity

When they are absent from an ecosystem, due to predation by other animals, these prey species will develop into large populations and disrupt the natural balance that exists within marine ecosystems.

Although Pacific Sharpnose Sharks are still found throughout a large portion of their range, as with many species, there exist numerous human-related threats.

Threats:

• Commercial Fishing
• Gillnet Bycatch
• Longline Fisheries
• Habitat Degradation Coastal

Pollution

Climate Change

They are being commercially exploited for:

• Food (meat)
• Fish Fins
• Fish Meal

Because of their slow reproductive rate compared with most fish, excessive commercial exploitation could lead to declines in local populations over time.

Many people are working together to protect both fish populations in our oceans and coastal wetland ecosystems so that we can maintain healthy, sustainable fisheries for generations to come.

To conserve these fisheries, there are many important things that need to be done:

• Monitor what is being caught commercially
• Reduce bycatch (the catching of non-target species)
• Protect areas where young fish live
• Improve how fisheries are managed
• Create Marine Protected Areas
• Scientists are studying shark populations around the world to better understand population trends and develop effective conservation methods.

They look almost identical because of their names, but they inhabit vastly different ocean basins and have adapted to a variety of aquatic environments.

Atlantic Sharpnose Shark:

• Average smaller size
• Found from Canada down to Brazil
• The body has white dots all over it

Pacific Sharpnose Shark:

• On average slightly larger than the Atlantic sharpnose
• More pointed nose compared to other sharks
• Live in Coastal Tropical Waters

Learning more about Pacific Sharp Nose Sharks can help to illustrate how connected the ecosystems of our oceans really are. More continued research and education regarding Pacific Sharp Nose Sharks would be beneficial to understand their behavior and ecology. More importantly, responsible fishing practices, along with protecting habitats that contain Pacific Sharp Nose Shark populations, would help to protect them for future generations.

Every species of shark has unique behaviors and adaptations and every species plays a unique and important role in the ecosystem. Learning about the diversity of sharks can aid in understanding why marine conservation is so important. Learn about more species of sharks by reading more shark species guides on Sharklady to learn about each species’ habits, hunting methods, reproduction, and contributions to the health of the ocean.