Leopard Sharks Back In San Diego

Leopard Sharks back in San Diego for the summer of 2021. This page will be updated every year when these beautiful specimens arrive again.

Every year, thousands of Leopard Sharks make their way into the warm, shallow waters of Southern California. While several hundred reside on the shoreline of San Diego year-round, the majority are believed to come and go. So why are they here? What’s the draw?

While I do say “come and go”, it’s important to note that they aren’t believed to travel very far. The research is unclear as to whether they simply head out deeper or disperse. For all we know, they might actually be in San Diego year-round. There just isn’t enough research out there yet. One thing researchers have gathered is that these beautiful sharks love “The Cove”.

Up until 2013, no one knew why these sharks made such distinct, seasonal swarms to La Jolla Cove. But, after some time, researchers began to detect a pattern.

Why Leopard Sharks Come to La Jolla

An initial assumption was for the hunting grounds as the Cove offers an incredible habitat. But, that’s not actually why they’re here. In fact, within their congregations at the Cove, these sharks aren’t looking to feed, nor mate. So what’s the deal then?

We know leopards can be found up and down our coast from Baja through Oregon and they definitely hunt throughout that range (as they’re caught up and down the coast). We’ve now learned that nearly 97% of the leopard sharks that aggregate in La Jolla Cove are females! Furthermore, it was determined that many (if not most) are pregnant.

These pregnant females are drawn to La Jolla Cove for a couple of its unique characteristics. 1.) Temperature and 2.) Marine landscape. These pregnant females find their way to the warm and calm waters of the cove to conserve energy while expediting their pregnancy. In other words, they’re here to incubate.

The incubation period for leopard sharks lasts on average between 10 and 12 months (1). So, this leads us to the next important aspect of summertime for Leopard Sharks.

Leopard Shark Mating Season

Studies have suggested that 97% of leopard sharks here in La Jolla are females, you might be wondering how mating would even be possible. To be clear, NO, the males that make up that 3% of the local population are not purely responsible for impregnating the other 97%. In fact, in a recent study, it was found that “multiple paternity was detected in only 36.4% of genotyped litters sampled from mothers collected in LJ” (2). While studies like this are based on a limited population, they still provide valuable data.

Also, keep in mind that these statistics were taken strictly from a La Jolla site. Male Leopard Sharks are found up and down the coastline of California! Within the same study, it was suggested that the large congregation of exclusive females in La Jolla could also “function as a refuge from males by reducing harassment in the form of excessive mating attempts” (2). That being said, it’s not that San Diego doesn’t have many male leopard sharks, La Jolla is simply a gathering point for female leopards.

Mating

With that, yes, leopard sharks do in fact mate in the waters of San Diego, but maybe not so much in La Jolla. Leopard shark pupping season, according to Nosal (2013), occurs sometime between April and May. Believe it or not, after a female leopard shark has reached maturity (usually at 10 years old), she will mate every year (1). So, given that the gestational period is 10-12 months, a female Leopard Shark will give birth and then mate again within the next 2 months (give or take a month). It really is quite remarkable!

These female leopard sharks will begin to spend around 70% of their day in the shallow, warm waters of La Jolla just after they mate and become pregnant. They do this in an attempt to “speed up” their gestational period by using the warmth of the water while they conserve energy due to the lack of waves in the Cove.

Males Vs Females

In the same study I referenced earlier, sites in Del Mar and La Jolla tracked the San Diego leopard shark population. The authors found that in La Jolla, the highest numbers of females were present during the months of late-June through early-December (2). They also found that the volume in population presence was directly correlated with the temperature of the sea surface and indirectly correlated with swell height. Additionally, the arrival of females at the La Jolla site lined up with the Summer Solstice and the departure lined up with the Winter Solstice (2).

In terms of male leopard sharks, the males highest population volume was during the months of late-April to early-October and was also directly correlated to the temperature of the sea surface (2). I can attest to this as most of my male sharks have come in the early goings of the season.

Facts Overview About The Leopard Shark

• Leopard Sharks have an estimated max life expectancy of 30 years!
• La Jolla population is said to be 97% female (2).
• Pregnant females use the warmer waters of La Jolla and the rest of San Diego for incubation of pups.
• Leopard Sharks give live birth as their eggs remain inside until fully formed.
• Gestational period of 10-12 months
• Average litter is 15-20 pups with a range of 7-36.
• Males mature at 7-13 years (2.3-3.9 ft)
• Females mature at 10-15 years (3.6-4.3 ft)
• They have about 75-100 small teeth
• Their skin has a sand paper-like texture
• A Leopard Shark pattern is like a fingerprint. No two have the same pattern
• Females especially prefer calmer and warmer waters (2).
• The arrival and departure of females correlates with the summer and winter solstice respectively (2).
• Males appear in larger numbers earlier than females (2).
• 50% of females and 60% of males return to la Jolla every year (2).
• Multiple paternity was detected in only 36.4% of genotyped litters sampled from mothers collected in LJ (2).
• Leopard Sharks might spend 80% of time in water less than 2 m sometimes recede to deeper waters at night up to 53.9 m and 12.7 degrees C (2).

If you plan on fishing for leopard sharks, I highly recommend reading my page that specifies what tactics, gear, tackle, and other tips that I use to target leopard sharks. I also recommend releasing every shark you catch.

My recommended gear and tackle for the occasion:

• Rod: Fiblink Moonsniper (12 or 13 feet)
• Reel: Penn Battle 6000 or 8000 (II or III)
• Mainline: 50-pound braid
• Top shot: 100-pound nylon coated mono
• Shark Rig: (Buy Here)
  • Wire: AFW 90 lb Nylon Coated Wire Leader Line
  • Hooks: 7/0 Circles
  • Swivel: 3-Way Barrel Swivel
  • Crimps: AFW #6 Crimps
  • Weight: 8-ounce pyramid or 6-ounce sputnik

References:

1. Monterey Bay Aquarium. (n.d.). Retrieved 2020, from https://www.montereybayaquarium.org/animals/animals-a-to-z/leopard-shark

2. Nosal, A. (2013). Demography, movement patterns, and mating system of leopard sharks (Triakis semifasciata) aggregating along the open coast of southern California, USA. Retrieved from https://escholarship.org/uc/item/6q76v2sh