Freshwater Fish, Hydrophilic Hearts

The significance of Zebrafish in research

tmp_dd354153f714ce51096c487d5074951d_KTA0Jy_html_7757336bToday our topic of interest is the zebrafish (Danio rerio). This is an organism that holds a special place in my heart. As an aspiring young scientist I was drawn to the marine sciences. I was curious but I was clueless as how to get there. So, I went on to my undergraduate studies pursuing a degree in Bioscience (this was my safe choice). If there’s something I learned its that marine organisms are everywhere in science and math. For example: fish make great examples in anatomy and physiology, plankton are important subjects in microbiology, fisheries make for an awesome example in economics or most math classes. My favorite example? The zebrafish.

The zebrafish is a freshwater fish that belongs to the minnow family. What’s so crazy about this small thing? It’s a model organism! A model organism is a species that is used to better understand biological processes. Model organisms are easy to maintain, tend to breed in large numbers, and have short generation times. Basically, they make genetic research a little easier. The zebrafish was first used as a model organism in the 1960s.

Zebrafish Development | Amacher, S. L. (2001)

What so great about them?

  1. Cheaper than mice
  2. Embryos develop in a day
    • The embryos are also clear & they develop externally which makes it easier to analyze them
  3. The complete genome of the zebrafish was published in 2013.
    • Its genome is 1,505,581,940 base pairs in length → contains 26,247 protein-coding genes
    • 70% similar genes to humans

What important research topics have zebrafish have contributed to?

  • Adult cardiac disease
  • Tuberculosis research
  • Cancer research
  • Toxicology research
  • Organ Development ex: kidney
  • Forward genetics → a phenotype is observed, the genes responsible for that phenotype are identified
  • Reverse genetics → a gene with an unknown function is identified, gene expression is knocked down, the purpose of the gene is identified

Watch the following videos to learn more:

Zebrafish Research | Behind the Scenes of the Johns Hopkins Zebrafish Facility

Fighting Cancer with Zebrafish | Dalhousie University


Avians, Hydrophilic Hearts

Great Blue Heron

Recently I have become more interested in birding. Birds are fascinating creatures, and each species seems to have its own personality. The first time I encountered a Great Blue Heron (Ardea harodias) was at one of my favorite local New York State Parks. I was strolling down a marshy beach, and out of nowhere a majestic bird took flight and cruised away. They quickly become one of the favorite parts of my summer hikes.

Great Blue Heron with golden shiner | Photo taken by Tom Davis

During my previous semester of grad school, I presented on “The Importance of Salt Marshes in Avian Conservation.” Something I learned was that most bird species are towards the top of the food web, so they are great indicators of how healthy an ecosystem is. Due to its wide distribution the Great Blue Heron population is currently considered stable, but a major threat is the destruction of coastal wetlands.


gbh breeding map
Great Blue Heron Range Map – image obtained from

Another neat thing I recently learned is that the Great Blue Heron is a partially migratory species. If you reference the figure above, you can see that the Great Blue Heron is found year round in a majority of North America. In places where the winters are cold, the birds will migrate to areas where food is available.


Fun Facts

  • Great Blue Heron weigh 5 to 6 pounds (birds have hollow bones!)
  • Juveniles tend to be more grey in color. As adults they have bright yellowish bills and black head feathers.
  • When in flight the Great Blue Heron seems more two toned (this is when you can really see the blue!)
  • Heron have a lifespan of 15-25 years.
    • sexual maturity is reached around 22 months (males and females).
  • Great Blue Heron are protected under the Migratory Bird Treaty Act

majestic-great-blue-heron-up-closeNote: All images came from The Cornell Lab Of Ornithology Macaulay Library

Hydrophilic Hearts, Marine Mammals

Bearded Seal

The weather here in New York has been awfully chilly lately, which has inspired me to write about an arctic species today.

bearded seal

The Bearded seal (Erignathus barbatus) gets its name from the whiskers on its face. At maturity adult seals have brown to gray fur. They can grow to be about 7 feet long, and on average weigh 400-500 lbs . Females are typically larger than males. In terms of habitat, bearded seals prefer pack ice and shallow water depths (less than 200 meters). These seals are benthic feeders, so they typically eat shrimp, crabs, clams, and whelk. They will occasionally feed on fish such as sculpin and cod. Seals rely on ice for feeding, breeding, and resting. As of 2016 they are of least concern on the IUCN Red List.


This map shows that Bearded seals tend to be found in the Bering, Chukchi, and Beaufort seas in Alaska

Fun Facts

  • Bearded seals live about 25-30 years (maximum)
  • Bearded seals have 4 nipples! (most seal species have 2)
  • The Alaska stock is the only stock of bearded seals in U.S. waters.
  • These seals are part of the subsistence harvest in Alaska
    • The Alaska National Interest Lands Conservation Act is a United Stated federal law that allows this to take place.
    • The Marine Mammals Protection Act usually prohibits harassing, feeding, hunting, capturing, killing, and importation of  of any marine mammal or marine mammal product.


  1. pollution
  2. climate change
  3. ocean acidification

Note: “There is no evidence of any impact from hunting on Bearded Seal population numbers. For example, reports from Alaska Native subsistence hunters do not give any indication that Bearded Seal numbers have declined (Quakenbush et al. 2011).” – IUCN Red List

Why should we care?

There is no accurate population count at this time, but it is estimated there are about 500,000 worldwide. Bearded seals have played a big role in Alaskan native history. The loss of this species would greatly impact Alaskan culture. Not to mention, have you seen that cute face?

Bearded seal hauled out on ice – Image from NOAA Fisheries
  • IUCN Red List → the International Union for Conservation of Nature’s Red List of Threatened Species (watch this video to learn more)
  • subsistence harvest → hunting, fishing, and gathering of wild resources for food, raw materials, and other traditional uses.
Hydrophilic Hearts

An Affinity for Water

Welcome! I started this blog because I am a lover of the ocean and most bodies of water. There are so many interesting organisms that have mastered living in the water and I wanted to share my love for them. What I post about will range from fishes, marine mammals, microscopic organisms, plants, and so on. Feel free to submit something you would like to learn about.

“There’s nothing wrong with enjoying looking at the surface of the ocean itself, except that when you finally see what goes on underwater,you realize that you’ve been missing the whole point of the ocean. Staying on the surface all the time is like going to the circus and staring at the outside of the tent.”
Dave Barry