Are you unknowingly supporting the shark fishing industry?

Picture by Mark Conlin, UIG VIA GETTY IMAGE

Did you know that you could be unknowingly supporting the shark fishing industry? Meat and liver oil are used from sharks and could be sold to you without your knowledge. Squalene is a chemical compound found in shark liver oil that is used by a lot of cosmetic and makeup companies. It’s used in products such as moisturizers, anti-aging serums, deodorants, lipsticks, eyeshadows, and more! Squalane is also used in some products, which is derivative of squalene. Make sure to check your products before you buy them to make sure you aren’t purchasing from brands that use shark in their products. Some brands label their products as all natural or vegan, but still use shark liver oil; check all of your labels before you buy to help reduce shark fishing!

Shark meat is another way you could be buying shark without knowing it. Shark meat is often sold under different names, such as whitefish, flake, dogfish, rock salmon, and many more. Always be aware of what you’re buying and look up any names you are unsure of! Some pet food companies use shark meat in their foods, so also make sure to check the ingredients list on your pet foods. Shark meat is high in mercury, which is toxic to consume. So, avoiding shark meat is best for your health as well as sharks’!

If you like shark tooth jewelry, make sure you’re buying fossilized teeth and not the bright white ones! The fossilized teeth will be cream, brown, or black in color. Bright white teeth came from a shark that has recently been killed. If you do find a shop selling new shark teeth, avoid purchasing from that shop, so you aren’t indirectly supporting shark fishing.

For more information on how to help save the sharks, visit @oneoceandiving or @oneoceanconservation on Instagram.

All About Hawai'i's Tiger Shark Season

Three miles off O‘ahu’s North Shore sits a three-hundred foot drop off, a natural upwelling of nutrients drawing schools of Galapagos and sandbar sharks. Summer begins a period of less rain and more daylight on the islands, and it also starts the slow trickle of tiger sharks, sometimes twice the size of the other species, coming closer and closer in to mate and lay their pups. By fall, the social dynamic between all of these species changes, as tiger sharks reclaim their position as dominant.

Mariah Meyer, a safety diver, started with One Ocean in February of 2022. She’s seen this dominance shift in our dive site through multiple seasons now, so we sat and talked all about tiger season—why it exists, what changes, and why it matters.

Photo by Andy Hawes

SF: What is the first thing that comes to mind when you think of tiger season?

MM: F*** yeah. I get so excited for the big girls to come around. So excited.

SF: What are some of the ways your job changes?

MM: We are always aware in the water, like always super aware, but you have to be extra on your toes, and you really pay attention to shark behavior. When you see the sharks, especially the Galapagos sharks, leave, you know “Ok, there’s somebody in the area,” and you can feel the tiger vibes. It sounds like I’m making it up, but you gain this sixth sense of knowing and feeling and understanding where they are. There is totally an energy shift.

Photo by Bre Carrin @brebythesea

SF: How does interacting with guests change?

MM: You have to let them know the rules a little bit better. Things have to be stricter. Tiger sharks are not sharks to mess around with. Yeah, they are beautiful, amazing, apex predators. They’re not cold-blooded killers, but they’re not puppies either. There needs to be a level of respect that everyone needs to have when we enter the water.

SF: How does interacting with sharks change?

MM: The Galapagos do tend to get shier when we have tiger sharks around. It’s normal, they’re smaller. During my first tiger season I was like, “What is going on?” But now that I’ve been through a whole one before I’m like, “I see what’s going on. I know why they’re doing this. I know why they’re doing that. Ok, I know even if we tried to do an engine start they wouldn’t come up because they know that something’s around.” You totally understand the whole conversation that the sharks are having better.

Photo by Bre Carrin @brebythesea

SF: What’s something that someone wouldn’t expect when a tiger shark comes around?

MM: How much they love them. Everyone is so scared, you know? Because tiger sharks are painted to be this big, ferocious predator, but they’re honestly kind of derpy. Really adorable. They have these cute little faces, you know? I love them so much, and [guests] see them and they’re like, “Oh my gosh, that was the coolest thing ever,” and I’m like “Yeah, you just swam with a sixteen-foot tiger shark. Not many people can say they did that.” It’s just a really magical experience. Everyone is so stoked.

SF: One of the things that I didn’t think about before is when there are tiger sharks in the area, sometimes you don’t see them, but all the other sharks know they’re there, so some days in the middle of tiger shark season there’s a greater chance of not seeing any sharks.

MM: Usually we will see one or two, but they will be kind of shy because the other sharks know. They have their lateral line, they have all their hearing senses and all these ways that they know, whereas we just know from their behavior that there’s a tiger shark around.

Photo by Paul Johnson @paulphinphotography

SF: Tiger sharks come shallower to lay their pups and that’s why we see more of them, right? I’ve also read there may be some correlation with the humpback whale migration season. It’s almost exactly opposite of when the whales are here, so while they prey on calves perhaps they hide from the adults.

MM: Scientists time it with pupping season and mating season, where [tiger sharks] hang around here or they go to the northern Hawaiian Islands or they vibe through the Hawaiian Islands, but there are also tiger sharks that are residents of different islands. Big Island has some tiger sharks that are residents specifically of Big Island. I’m not sure which tiger sharks are specific residents of O‘ahu. I’m sure if you had long term—I’m talking five-to-ten-year term—data, you could figure out which ones are residents of O‘ahu. But there has also been a ton of research about another type of shark that goes on a two-year migration cycle, where they don’t go to the northern Hawaiian Islands every year, or they go up and around and then they go here, and then they go here. It’s not that we are going to see this one every year. We might see them every two years.

There’s not a ton of data on tracking large sharks in general because to track a shark you basically need two types of tags, a satellite tag or an acoustic tag. An acoustic tag works like a cellphone to a cellphone tower, and basically the cellphone towers in the water are these acoustic receivers, but they have a range of maybe 500 yards max, so for that acoustic tag you need to have receivers in the water, and I don’t think anyone is going to be putting receivers in the water all the way up to the northern Hawaiian Islands. That’s super super expensive. They do it with white sharks in California. The satellite tag, which goes on the dorsal fin and transmits a signal to the satellite every time the dorsal fin pops out of the water. Obviously you can’t do it under water, and how often do sharks come up to the surface? They don’t need to breathe, so there isn’t a lot of data on them because it’s really hard to collect that data.

Photo by Bre Carrin @brebythesea

SF: Can you describe a recent interaction with a tiger shark or one that stands out in your mind?

MM: This was maybe two or three weeks ago. I was out on a charter one day, and we had three different tiger sharks around. I believe it was Miso, Luana, and Nikki, and it was so awesome seeing all the different girls interact, because obviously Nikki is huge. She’s the biggest. Luana is pretty big too. She’s like fifteen-sixteen feet. Miso is like ten to eleven-twelvish feet, so she’s definitely a smaller female. She’s a young adult, so she’s spunky. She’s feisty, so while these bigger girls are trying to push Miso out because she’s a smaller shark, she is holding her own with the bigger girls, and it’s really really cool to see how not just the size of tiger sharks can determine their dominance, but their personality too.

SF: It's more complicated than just how big they are.

MM: Yeah. Kilauea, my tiger shark, she’s so shy. She’s like, “Nope.” She does not like confrontation. Whereas Miso is like, “Nah, I am here. This is my space.” She does not care, which I think is so cute.

Migration of the Hawaiian Tiger Shark

Tiger sharks are one of the ocean's most iconic and feared predators. With their massive size and fearsome reputation, they can be found in many areas of the world, including the waters surrounding the Hawaiian Islands. These sharks are known to migrate long distances, which has been studied extensively by scientists over the years.

Tiger sharks in Hawai'i are known to migrate between the main Hawaiian Islands and the nearby atolls and seamounts, such as French Frigate Shoals and the Northwestern Hawaiian Islands. These migrations occur seasonally, with the sharks traveling to different locations during different times of the year.

One study conducted by scientists from the University of Hawai'i at Manoa used satellite tagging to track the movements of tiger sharks in the Northwestern Hawaiian Islands. The study found that the sharks traveled long distances, with some traveling over 2,500 kilometers in just a few months. The researchers also noted that the sharks tended to stay in deeper waters during the day and move into shallower waters at night.

Another study conducted by researchers from the University of Tokyo found that tiger sharks in Hawai'i tend to migrate toward the main Hawaiian Islands during the winter months. The study used acoustic tagging to track the movements of the sharks and found that they were more likely to be found in the waters surrounding the main Hawaiian Islands during the winter.

So why do Hawaiian tiger sharks migrate, and what factors influence their behavior? The exact reasons for these migrations are still not fully understood, but ongoing research is helping to shed light on this fascinating behavior.

One factor that may influence the migration patterns of tiger sharks in Hawai'i is changes in water temperature. Like many other shark species, tiger sharks are ectothermic, meaning their body temperature is regulated by the temperature of the surrounding water. Changes in water temperature may prompt the sharks to move to different locations in search of more favorable conditions.

The availability of prey is another factor that may influence the migration patterns of tiger sharks in Hawai'i. Tiger sharks are opportunistic feeders that will eat a wide variety of prey, including fish, turtles, seabirds, and even other sharks. As the availability of different prey species changes throughout the year, the sharks may move to different locations in search of food.

Breeding behaviors may also play a role in the migration patterns of tiger sharks in Hawai'i. While little is known about the mating habits of these sharks, it is thought that they may mate in deeper waters and then move to shallower waters to give birth to their pups. This could explain why the sharks tend to stay in deeper waters during the day and move into shallower waters at night.

Despite their fearsome reputation, tiger sharks are an important part of the marine ecosystem in Hawai'i. They help to maintain a healthy balance of predator and prey species, and their migration patterns are an important area of study for scientists interested in understanding the behavior of these powerful predators. By tracking their movements, researchers can gain valuable insights into the factors that influence their behavior and help to inform efforts to protect these important species.

Overall, the migration patterns of Hawaiian tiger sharks are a fascinating subject of study for scientists and laypeople alike. By continuing to study these magnificent creatures, we can better understand the complex interactions between predator and prey species in the ocean, and work to protect these important and iconic animals for generations to come.

References:

• Papastamatiou, Y. P., et al. "Telemetry and random walk models reveal complex patterns of partial migration in a large marine predator." Ecology 94.11 (2013): 2595-2606.

• Watanabe, Yusuke Y., et al. "Seasonal and ontogenetic changes in depth distribution