Gulf of Guinea

Let’s travel to the eastern side of the Atlantic Ocean, right off the coast of Africa. Between Cape López, near the Equator, and Cape Palmas lies a body of water known as the Gulf of Guinea.

The Volta River and the third largest river in Africa, the Niger River, are the major rivers that feed into the Gulf of Guinea. Because of the runoff from these two rivers, and the high amounts of rain along West Africa, the gulf’s water is lower in salinity than other parts of the ocean. This warm water is separated from deeper, colder, saltier water by a shallow thermocline.

A thermocline is a thin, distinct layer in a body of water that marks when the temperature of the water rapidly changes with depth. In the ocean, it separates the upper mixed layer near the surface and the deep, calm water below. Thermoclines exist in the atmosphere as well.

Off the coast of Guinea and Côte d’Ivoire, a seasonal coastal upwelling forms in the gulf. An upwelling occurs when cold, nutrient-rich water from the deep is brought up to the surface water. This nutrient-rich water creates a boom of activity that attracts organisms from every level of the food chain, including fish, birds, and mammals. When the nutrients are depleted, the organisms move on.

The Gulf of Guinea has been nominated as a Hope Spot. The beaches around the gulf contain prime nesting sites for leatherback sea turtles, which are a threatened species. Sea turtles grow for many years before they reach sexual maturity, and the process of reproduction can be fatal to females. Newly hatched sea turtles have a high mortality rate because of predation before they reach the ocean and from human activity. It’s extremely important to protect these nesting sites.

Within the Gulf of Guinea lies the island nation of São Tomé and Príncipe, which contains vital habitat for humpback whales, African manatees, dolphins, and soft corals. Humpback whales are considered endangered by the IUCN Red List their populations are threatened by whalers and by getting struck by cruise liners and cargo ships. African manatees are classified as vulnerable.

The Niger River is being explored for oil and gas mining, which could have a serious impact on the Gulf of Guinea. Luckily, non-government organizations (NGOs) have been working hard with both government and international partners to develop green practices to extract those natural resources. The NGOs have also been developing full-scale wildlife law enforcement programs to protect the gulf and its wildlife.

This is definitely a cool Hope Spot and I wish them the best of luck. If you travel to any of the beaches containing turtle nesting sites, see if there are any volunteer programs you can join. I know in the US there are volunteer programs that help get the baby sea turtles into the water. May not be the ideal vacation plan, but it’ll be something memorable to share with your friends and family!

Sources:
https://mission-blue.org/hope-spots/
https://www.britannica.com/place/Gulf-of-Guinea

Humpback Whale

Humpback whale jumping out of the water. Photo taken from pexels.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Balaenopteridae
Genus: Megatera
Species: Megatera novaeangliae

When we speak, hum, sing, etc. we make those noises by vibrating our vocal cords. Sometimes, when you hum or hold a note, you can even feel the vocal cords in your throat. Whales can also sing. In fact, male humpback whales sing to communicate and can be heard for miles by other whales, each “song” lasting up to about 30 minutes.

Fun fact: scientists don’t know how humpbacks pull off singing, because they have no vocal cord.

Humpback whales get their common name from the way they arch their back when diving. They aren’t the largest or heaviest whales in the world, but they do have the longest flippers. Their fluke and wing-like flippers can help you identify the whale as a Megatera novaeangliae, and the unique white splash-like markings on those appendages allow scientists to distinguish between individuals, like a fingerprint.

These creatures can be found in all of the world’s oceans, in both tropical and polar regions, though they don’t venture too far up into the poles.

M. novaeangliae are a type of baleen whale, meaning that they don’t have teeth like we do, and they take in large amounts of water that, hopefully, contain a lot of krill and small fish. Humpback whales are different from other baleens because they can actually trap their prey through a process that is better to watch in a video or documentary (e.g. Blue Planet).

When humpbacks find swarms of krill or schools of small fish, they will try to gather them together. They do this by exhaling air while they spiral around their prey. This action creates a “bubble-netting” that confuses and traps the prey, allowing humpbacks to dive below and lunge upward to feed upon their prey. Like I said, I highly recommend watching this on a video or a documentary because it’s incredible to see, and if you get a chance to see it in person, all the better!

I feel like humpback whales are underappreciated. I first learned about them when I started watching nature documentaries in high school, but it wasn’t until college that they started getting more fleshed out in my mind.

They’re amazing creatures that produce eerily beautiful songs. I should know; I had to listen to some in a lab class in college, and they have a unique feeding behavior for baleen whales. While they’re not endangered or threatened, their populations have been reduced to a fifth of what it once was due to whaling practices—that’s mind-blowing to me!

If what you’ve read has piqued your interest, please take the time to learn more about these creatures. There’s so much that I couldn’t add, and who knows, maybe your curiosity will lead you into a job that will allow you to understand the mysteries of their singing.

Videos of bubble netting:

Sources and more reading:
Ocean: The Definitive Visual Guide made by American Museum of Natural History
Ocean: A Visual Encyclopedia made by the Smithsonian
Marine Mammals Evolutionary Biology 3rd edition by Annalisa Berta, James L. Sumich, and Kit M. Kovacs
https://animaldiversity.org/accounts/Megaptera_novaeangliae/
https://www.chesapeakebay.net/discover/field-guide/entry/humpback_whale
https://oceanwide-expeditions.com/to-do/wildlife/humpback-whale
https://www.nationalgeographic.com/animals/mammals/h/humpback-whale/
http://wildwhales.org/speciesid/whales/humpback-whale/
https://www.fisheries.noaa.gov/species/humpback-whale
https://us.whales.org/whales-dolphins/species-guide/humpback-whale/