The Whale Shark (_Rhincodon typus_), also known as 'Tiburón Ballena' in Spanish, holds the title of the largest fish in the ocean. Regularly visiting the Galapagos Marine Reserve, this species is currently classified as endangered. Noted for their imposing size, Whale Sharks are also distinguished by their peaceful demeanor, making them a focal point of interest for marine biologists and ocean enthusiasts alike.

Size and Appearance

Reaching staggering lengths of up to 20 meters and weights exceeding 30 metric tonnes, Whale Sharks possess a distinctive appearance. Their skin is primarily grey to blue, adorned with unique white spot patterns amidst vertical and horizontal stripes, creating a chequerboard effect. The head of a Whale Shark is characteristically broad and flat, equipped with a large mouth that can span up to 1.5 meters wide. In contrast, their eyes are relatively small in proportion to their body size.

Habitat and Distribution 

Global Presence

Whale Sharks exhibit a wide geographical range, inhabiting warm and temperate seas globally, with the notable exception of the Mediterranean Sea. Their migratory nature often leads them to coastal locations where predictable aggregations, known as 'whale shark seasons,' occur. These aggregations are typically linked to local surges in marine productivity, such as coral or fish spawning events.

Galapagos Habitat

In the Galapagos, Whale Sharks are predominantly observed in the northern waters near Darwin and Wolf Islands. Darwin’s Arch, in particular, serves as a notable feeding ground, attracting these giants due to the upwelling currents that bring a rich supply of plankton.

Behavior and Diet 

Feeding Habits

Whale Sharks are primarily planktivores, subsisting on a diet of plankton, small fish, krill, and fish eggs. Remarkably, they can consume up to 90 pounds of food each day. Their feeding technique, known as ram-filter feeding, involves swimming near the ocean surface with their mouths open wide, allowing them to channel plankton-rich water for sustenance.

Migration and Behavior

The migratory routes of Whale Sharks encompass thousands of miles each year, linking feeding grounds across the globe, including the western coast of Australia, Indonesia, Belize, and the Galapagos Islands. Despite their size, Whale Sharks are surprisingly inefficient swimmers, traveling at a speed of just over 3 miles per hour and relying on their entire body for propulsion, a unique trait among fish species.

Reproduction and Lifecycle 

Breeding Behavior

The reproductive cycle of Whale Sharks remains largely enigmatic. Known to give birth to live young, studies suggest they employ ovoviviparous reproduction, where eggs hatch inside the female before birth. A single pregnant female can carry more than 300 eggs. Upon birth, baby Whale Sharks measure between 40-60 cm and exhibit rapid growth rates of approximately 18 inches per year.

Galapagos Significance

The Galapagos waters are a significant habitat for predominantly female Whale Sharks, a large proportion of which appear to be pregnant. This unusual demographic distribution is a subject of ongoing scientific investigation, with researchers seeking to understand the reasons behind this aggregation pattern.

Conservation Status and Efforts 

Endangered Status

The Whale Shark faces the threat of endangerment, primarily due to factors such as illegal fishing, unintentional capture in fishing nets (bycatch), and collisions with ships. Their role as nutrient carriers across marine ecosystems underscores their ecological importance. Consequently, international trade in Whale Shark meat or products is prohibited under CITES (The Convention on International Trade in Endangered Species of Wild Fauna and Flora).
 

Research and Protection

Projects like the Galapagos Whale Shark Project aim to deepen our understanding of Whale Shark migratory patterns, behaviors, and potential birthing sites. This research is pivotal for the development of effective conservation strategies. Efforts also include environmental education for local communities to foster participation and support for conservation actions.

Best Time and Places to Observe 

Optimal Season

The prime season for observing Whale Sharks in the Galapagos spans from June to November, with peak sightings occurring in August and September. However, due to the variable nature of their presence, sightings are not guaranteed, even during peak season.

Prime Locations

Darwin and Wolf Islands in the northern Galapagos are the prime spots for encountering these creatures, with Darwin Island offering consistent opportunities for divers to observe adult female Whale sharks.