Tag Archives: Marine Mammals

Harbor Seals 101

Have you ever noticed a speckled mammal trying to camouflage into rocks along the California coast?! If so you may have spotted a harbor seal! Harbor seals are marine mammals that belong to a group called pinnipeds (meaning “fin-footed”). Harbor seals are found north of the equator along the Atlantic and Pacific Oceans. They range from Alaska all the way down to Mexico, and are commonly found in coastal waters, rocky islands and on sandy beaches.

harbor seals

(Harbor Seals along a coastline.)

Harbor Seals typically have spotted coats in a variety of shades that range from white, dark browns, and even black. They range around 5 to 6 feet in total length and have very small flippers. They move along on land by flopping around on their bellies. They also lack earflaps, and have internal hearing. A fatty tissue known as “blubber” helps to keep them warm. They also have very large eyes that help them to see in dark, deep water.

A baby harbor seal is called a pup. When pups are born they can swim at birth and sometimes when they are tired they will even ride on their mother’s back! Pups are weaned around four weeks old and females will mate and give birth to one pup every year. Harbor Seals can reach a lifespan of up to 30 years!

The harbor seal spends about half of its time on land and the other half in water. They can dive up to 1500 feet and hold their breath for up to 40 minutes! An average dive however is typically shallow and lasts around three to seven minutes. Unlike humans, they breathe out before diving deep into the water. They then use oxygen that is already in their blood and muscles while underwater. Their heartbeat actually slows from around 100 beats per minute to just 10!


harbor seals 2

(Harbor seal lounging on a sandy beach.)

The diet of a harbor seal consists of flounder, sea bass, cod, squid, and octopus. They actually use their whiskers to help them hunt and navigate by sensing pressure waves from fish and underwater objects!harbor seals 1(Left: Harbor seal using its long whiskers to help it hunt for prey.)

All in all, the harbor seal is one charismatic marine mammal. From their cute appearance to their smooth swimming style, these seals have earned their cuddly reputation. Go out to the beach now and try to find one of these marine mammals on a snorkel so you can truly see their beauty!

Written By: Brooke Fox






Happy Manatee Appreciation Day!

Manatee Appreciation Day is a day devoted solely to raising awareness about these marine mammals. Once on the endangered list, the manatee is now severely threatened. But what makes manatees threatened in the first place, and what exactly are these creatures? The manatee is a very large, fully aquatic, marine mammal. They are commonly called sea cows because of their resemblance to cows on land. Unfortunately, the water is too cold here in California for manatees to live, but they enjoy living in warm tropical waters, like off the coast of Florida! They are slow plant-eaters and often graze on vegetation that grows in the water. They can reach up to over 1,000 pounds eating this vegetation, and can reach lengths of up to nine feet! Manatees spend about 50% of their day sleeping submerged underwater and surface only to take in a breath of air. They can hold their breath for approximately twenty minutes, but tend to surface every few minutes for air.These mammals are threatened due to habitat loss, boat collisions, and becoming entangled in fishing lines. Habitat loss in many coastal areas is one of the most significant reasons for decline in manatee populations. This is because there has been a lot of damage to marine vegetation, which manatees depend on for food. In the United States alone, there are said to be only around 3,000 manatees left in the wild.

Manatees at Florida power plant

A group of manatees is called an “aggregation.”

Boat collisions are another huge reason that manatee populations are suffering. Manatees are slow-moving animals, typically cruising around at speeds between three and five miles per hour. Fast moving boats may not be able to slow down or stop before colliding with a manatee, therefore, many areas have done their best to reduce boat speeds to protect these gentle giants. In many of these cases, manatees die from their injuries that are associated with these collisions.

A Florida manatee swimming near a boat’s propeller.

Manatees frequently become entangled in fishing line, which is another reason these animals are threatened. Fishing lines, hooks, and nets can easily become attached to the animal, causing them to get an infection. Entanglement can also cause manatees to drown, leaving them to be pulled under the surface, unable to get a breath of air.

So what can we do to help? If you live near bodies of water that have manatees in them, always be cautious. When driving boats through manatee zones, BE ALERT! Always obey the speed zones and remember that these sea cows could be coming up to the surface to breathe at any time. When near water that manatees could be in, do not feed or approach them. This could get them more used to humans, which in return could be harmful to their health. Something else we can do not only for manatees, but also for marine life all around us, it to pick up trash whenever we see it. This habit could save so many of our favorite marine friends’ lives! You can also celebrate Manatee Appreciation day by telling a friend or sharing this blog! Lets help spread awareness about our favorite type of cow… obviously, the sea cow!

Manatee pair

Don’t forget to Celebrate Manatee Appreciation Day just like these two happy manatees!

Written By: Brooke Fox


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Cloudy with A Chance of Marine Snow

Wouldn’t it be nice if our meals, snacks, and beverages just fell from the sky right into our hands as if it were rain or snow?  What if those Skittle’s commercials where little, fruity candies rained down from vibrant rainbows above your head were actually a reality?  Come on, admit it; at one point in your life, you wished that skittles would trickle on down on top of your head and waterfall right into your mouth and hands.  Instead of rain, what if it was drops of Coca-Cola or orange juice?  What a life it would be….I guess?

Well in our reality, rain is still cumulated water particles from the sky that get pulled down by gravity, rainbows are a distant visual spectacle that always disappear just when you are about to get close them, and our food still hides out in the pantry and refrigerator, lifeless and alluringly calling our names to indulge.  So then what’s the point of all this talk about food-borne weather phenomena?  Well, lets take a dive down to the very depths of the ocean to find out.

While food falling from the sky may not be our reality, it is for the Deep Sea believe it or not!  Communities of mysterious deep dwelling organisms actually obtain a majority of their diet from what falls from “the sky” (or the open water above, rather).  This descending, nutritious organic matter is more formally named, Marine Snow.

More clearly, marine snow is showering organic material that falls from the surface above down towards the bottom of the ocean.  It originates from dead animals, plants, plant-like organisms, such as algae, and even fecal matter.   Some of it even comes from inorganic matter, such as sand, silt, and other related materials.  Mass contributors of the falling snow typically come from plankton feasted on by bigger consumers.  Fish, invertebrates, marine mammals, and even zooplankton are examples of these predatory individuals.  As the dead, decaying matter descends from the upper layers of the ocean, they fuse together and accumulate into larger “snow-like” particles.  As these particles slowly make there way down, deep sea organisms that aren’t so lucky to find food on a frequent basis filter out the snow to obtain vital nutrients, like carbon and nitrogen, needed for optimal survival.  What ever is left continues to fall slowly until it is either consumed by other deep dwelling creatures or it makes impact with the ocean floor.  The time is takes for marine snow to typically reach the bottom is around two weeks.  Overtime, marine snow that doesn’t get eaten will slowly start to accumulate on the sea floor forming “oozy” mounds of decomposed matter.  These mounds will, in turn, become food for detritus buried within the floor or get sifted up by deep-sea conveyor currents that eventually work there way to the surface.   

Marine snow additionally poses as a major carbon sink on our oceans.  As mentioned above, these particles are rich in carbon and other organic nutrients.  The left over material that contributes to the bottom mound of organic ooze is highly composed of that carbon, which will sit and stay rested until it gets sifted up within the deep-sea currents and transported back to the surface where it can return to the ocean’s food web and to our atmosphere.  

Before you allow yourself to get bitter over the fact that it snows practically everyday within the ocean than it does on land, just know that 1). it ain’t the white, fresh, powdery goodness that falls from our sky during the winter months, and 2). it’s a natural life process that feeds the hunger that resides in the deepest part of our oceans and regulated the excessive amounts of carbon that hang out in our atmosphere and oceans.  Now how cool is that?  

Written by: John Cornett

Photo Links

Marine Snow – http://www.seamusketeer.com/single-post/2014/12/12/Marine-snow-falls-all-year-round

Marine Snow Diagram – http://www.deepseanews.com/2011/12/let-it-snow-let-it-snow-let-it-snow/

Under Pressure

The Deepest part of the ocean is about 36,200 feet or over 11,000 meters, which is deeper than Mt. Everest is tall by about 7,000 feet! Animals that live this deep have a remarkable amount of challenges that they have to adapt to in order to live, such as absence of light, freezing temperatures, and immense increases of pressure. Today we are going to talk about why pressure is increased as you go deeper as well as the effects that it has on many animals that live down there.

Have you ever been on a snorkel or a SCUBA dive and felt pressure on your ears as you go deeper down? Well, if you have, that is actually the air cavities inside your ears shrinking as you go deeper. As a rule of thumb the deeper you go in the ocean the more pressure is being forced onto your body. We normally measure pressure in atmospheres, which is the amount of pressure exerted by the Earth’s atmosphere. At the surface of the ocean we only have 1 atmosphere of pressure pushing down on our bodies. Each atmosphere is equivalent to 14.5 pounds per square inch, meaning you have 14.5 pounds of force pushing down on you right now. However, as you descend in your SCUBA unit or pressurized submarine, the pressure increases by 1 atmosphere every 10 meters (33 feet). So, at the deepest depths of the ocean, you have the weight of an elephant on every inch of your body, OUCH!

So how can animals that live and thrive in the deep depths of the ocean survive these immense pressures and we cannot? Inside of our bodies we have many air cavities that would pop and rigid bones that would snap when exposed to the pressure. So for invertebrates and fish that live in the Marianas Trench the simple solution is to remove the air cavities and have very flexible bones…if any at all! Fish do this by evolving past swim bladders, an organ that normally controls buoyancy. Many invertebrates do this by having hydrostatic skeletons; a fluid filled cavity surrounded by muscle, or no air cavities as well. Marine mammals like deep diving whales have incredibly flexible rib cages that can compress with the pressure and collapsible lungs that can withstand rupturing! This is exactly how Sperm Whales are able to dive down to 7,000 feet deep to battle and eat Giant Squid.


The Mammal Channel

It’s so exciting to see marine mammals at CIMI! With spring migrations in full swing, we are feeling very lucky to be seeing lots of grey whales, common dolphins, and Risso’s dolphins among many more in San Pedro channel.


Scientists still don’t know why Risso’s dolphins scar each other’s skin with their teeth in unique patterns like this. (Image credit: Cosmos Magazine)

What is a marine mammal?

Mammals have five characteristics that separate them from other animals: they breathe oxygen, have hair or fur, give birth to live young that females nurse with milk from mammary glands (called lactation), and are warm-blooded. Marine mammals are mammals that rely on the ocean for their primary food source.

What are some types of marine mammals?

There are five groups of marine mammals:

  • Whales and dolphins (cetacea)
  • Seals and sea lions (pinnipedia)
  • Sea otters (they’re members of the weasel family!)
  • Manatees and dugongs (sirenia)
  • and, yes, even polar bears! 

Where did marine mammals come from?

Isn’t it strange that mammals who need to breathe oxygen and keep warm live in underwater habitats? Scientists believe that marine mammals such as whales evolved from dog-like creatures that ate fish, and slowly developed characteristics that helped them spend longer in the water to hunt.

Why are marine mammals important?

Because they are big, beautiful, and some seem ‘cuddly’, and because so many species are threatened by poaching, habitat destruction, and pollution, marine mammals are often the “poster child” for ocean conservation. But they are more than just a mascot; marine mammals are apex predators in their habitats, meaning they are very important to keep other populations in check. For example, sea otters love to feed on urchins, and urchins are powerful ocean grazers. If a sea otter population is threatened, urchins often take over because their population grows so quickly in the absence of predators. This can create “urchin barrens,” or areas where habitat for small invertebrates and fish is completely destroyed because all the algae and kelp has been eaten by urchins!

Fun marine mammal facts:

  • You can tell a sea lion apart from a seal by looking at its front flippers, ears, swimming, and social behavior: sea lions have longer, more developed flippers that allow for easier motion on land. They also have small ear flaps, “porpoise” or play and flip at the surface of the water, raise young in large groups, and adopt orphan pups. Seals, on the other hand, have shorter flippers and are awkward on land. They have small ear holes instead of ear flaps, “periscope” or pop up for a quick look and breath before diving down for long periods of time, and are more solitary in their behavior.


California Sea Lions


Harbor seals (Image credits: NOAA/Dan Linehan)

  • Orcas and dolphins are “odontocetes,” which means “toothed whale.” They are carnivorous and eat mostly fish and small invertebrates. Most larger whales are “mysticetes,” which means “mustached whale” — named for the fibrous baleen that helps these massive creatures feed on tiny plankton and krill that they filter into their mouths.


No wonder this guy didn’t want to eat Nemo and Dory after all! (Image Credit: Disney)

  • A blue whale is the largest animal that is living — or has ever lived — on Earth, measuring in at 30 meters!


Blue whales are about three “Megalodons” long. Ssssh… don’t tell T-rex. (Image credit: Pukatea.blogspot.com)

We could talk all day about marine mammals at CIMI, but here are some other places to explore for more:

To learn more about marine mammals and see a longer list of species, check out the National Oceanic and Atmospheric Administration’s page about them here: http://www.nmfs.noaa.gov/pr/species/mammals/

To learn more about exciting new research about Risso’s dolphins, check out this article in Cosmos Magazine: https://cosmosmagazine.com/life-sciences/social-network-rissos-dolphins/

To learn more about marine mammal conservation and rehabilitation, check out the marine mammal center’s website at http://www.marinemammalcenter.org/

Harbor Seal

Harbor Seals(Phoca vitulina) are one of the few Pinnipeds found around Catalina Island. These are some more elusive seals, often times avoiding human interaction completely. These seals will spend their days either swimming in shallow wasters or sunning themselves on rocky outcroppings right off of shore. Harbor seals will often times poke their heads out of the water to observe and look out for potential danger. This habit is called periscoping. When the seals need to warm themselves from the cool California waters, they will drag their bodies onto rocks and lay out for hours. These seals can reach up to 6 feet in length and almost up to 300 pounds, most of their body weight consisting of blubber or fat.


Other Pinnipeds found along Catalina Island waters are Sea Lions and Elephant Seals. The Harbor Seals are the smallest out of the three.


Northern Elephant Seals

Did you know? Northern Elephant seals have one of the longest mammal migrations on the planet! They spend almost all their time venturing across the ocean, specifically in the North Pacific range, and travel from their rookery sites out to the continental shelf and back again twice in one year. This migration is done twice due to breeding and molting events, spending only about one month each time on the beach before returning back to the open ocean.

These animals are truly amazing, possessing some pretty impressive abilities. The longest recorded dive of an elephant seal was around 2 hours, and the deepest dive was recorded to be around 5,000 feet. These silly seals get their name from the gigantic nose that is grown by males at sexual maturity. This nose, or proboscis, helps the male by allowing him to make loud trumpeting echoes and this helps attract females as well as to assert dominance over smaller males. Males usually arrive at the breeding beach, or rookery, around January to scout out a spot on the beach. Then the females arrive and will mate as well as give birth to their newborns that they have been carrying since the previous year. The females will stay on the beach nursing their newborn pup for around 28 days before heading back into the water and leaving their pups to fend for themselves. Pups will band together and slowly learn how to catch food in tide pool areas before easing their way into the open ocean. The California coastline holds some of the largest elephant seal rookeries, where they return year after year for mating, birthing, and a catastrophic molt in the summer. During this catastrophic molt, they will shed their first layer of hair and skin, which is quite the sight for an unknowing onlooker! There are many great vistas and protected areas where the public can view these glorious seals in their natural habitat, but don’t get too close! Males can weigh in at a whopping 5,000 pounds, and will charge when threatened. The most miraculous thing about these elephant seals isn’t their size, stamina, or diving abilities. They were able to bounce back from the brink of extinction, with less than 100 individuals left by 1910. They were hunted for their rich blubber, but with the proper protection, are now thriving with an estimated population of around 200,000.


Thermoregulation Makes Me Hot – Sea Lions

I want those of you who have ever been cold on a snorkel to raise your hands in the air…No really, raise your hands in air—that’s the best way to stay warm in the water. Don’t believe me? Just ask the sea lions. Sea lions are marine mammals, and therefore endothermic. This means that they control their own internal body heat separate from their ambient environment. Many marine mammals, including sea lions, keep their core around 100 ˚ F. This can pose some interesting dilemmas for marine mammals that live in waters MUCH colder than their internal temperature. There are many adaptations that sea lions have to maintain their core temperature in the water, both physiologically and behaviorally—this process is called thermoregulation.


One behavioral modification that California sea lions enact to stay warm in the water is something called “jughandling”. Have you ever seen a sea lion waving at you from in the water? Maybe you have while on your boat ride to Catalina, or if you kayaked around Bird Rock. What appears to us as an overly-friendly sea lion saying “hello”, is actually a behavioral form of thermoregulation. Sea lion front flippers are not covered in fur, and therefore very susceptible to thermal conduction and convection, meaning they can transfer heat easily with the water and air. If a sea lion is cold in the water, all they have to do is raise a flipper to the sky and have the sun warm up their blood before it transfers back to their core. Vice versa, if a sea lion is too warm on the beach, they will take a dip into the water to cool off.
More than just behaviorally, many marine mammals thermoregulate physiologically as well. Fur is a frequent form of thermoregulation, because it can trap air against the skin keeping it warm. Blubber is an insulator utilized by large marine mammals such as whales, seals, and sea lions. Commonly (and wrongly) assumed to be a thick layer of fat, blubber is actually a complex matrix of collagen and adipose tissue that can both insulate an animal and keep it afloat.
So just like we may get cold in the ocean, marine mammals fall victim to the same tribulation. However, instead of warming up with a cup of hot chocolate or a steaming shower afterwards, they must rely on other adaptations to stay warm in the frigid ocean waters. So take a note out of the sea lion’s book, and next time you’re cold in the water, raise your hands up high and proud.

Author: Max Veenema


We would like to thank you for visiting our blog. Catalina Island Marine Institute is a hands-on marine science program with an emphasis on ocean exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and ocean happenings. This blog has been created by our staff who have at least a Bachelors Degree usually in marine science or related subjects. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science and ocean information. Feel free to leave comments, questions, or share our blog with others. Please visit www.cimi.org for additional information. Happy Reading!