Humback Whales Essays - Baleen Whales, Megafauna, EDGE Species

Humback Whales To look up into the mountains and see the steam rolling from a mountain stream on a cold winters morning is a beautiful sight. However, to look out over the horizon and see the white spray of salt water coming from the blow of a huge hump-back whale is much more exciting sight and a whole lot warmer. I lived in the mountains of Colorado for most of my childhood. The first time I had the opportunity to see the ocean was on a vacation to California, when I was about 15 years old. It was even better than I had dreamed it would be. The different animals in the ocean, the color of the water, and the warm sand between my toes was probably what led me to come to the islands of Hawaii. When I first saw the hump-back whale I was amazed at their huge size and how they could breach out of the water so gracefully. It is as if they were trying to play or show off. So when we were asked to choose a favorite animal, I had no problem deciding on the hump- back whale. The hump-back whale gets it's name from the distinctive hump in front of the dorsal fin and from the way it raises it's back high above water before diving. They are a member of the order Cetacea. This order is of aquatic mammals and the hump-back belongs to the suborder of the Mysticeti. The Mysticeti are the baleen whales which have three families and several species. The family in which the hump-back belongs is the Balaenopteridae, the true fin backed whale. The thing that separates this genus from the other fin-backed whales is the pectoral fins, which grow in lengths of about 5 meters (16.4 feet). This Genus is called Megaptera meaning great wing (Tinker 290). There was a controversy over the species name in the late nineteenth and early twentieth century. In 1932, Remington Kellogg finally settled the matter with Megatera Novaeangliae (Cousteau 84). The common English name is the hump-back whale. The hump-back whale lives in both the Atlantic and the Pacific oceans. Since we live in the Pacific I'll be discussing the hump-backs of the North Pacific. They migrate from North to South. In the months of July through September they gather in the Aleutian Islands, Bering Sea or the Chukchi Sea. They head south for the winter. They go to one of three areas: (1) Between the Bonin Islands, the Marianas Islands, the Ryukyu Islands and Taiwan; (2) The Hawaiian Islands, and (3) Along the coast of Mexico (Tinker 291). One of the reasons these whales go North is for feeding. They have a short food chain compared to most mammals. Phytoplankton turns sunlight into energy and this energy is consumed by zooplankton. The zooplankton and phytoplankton are eaten by small fish. The whale in turn eats the fish. The chain is complete when waste products or dead whales decompose. They have a very short time frame in which they eat compared to the twelve months out of the year. They have not been seen feeding in Hawaii. It seems that they only feed during the summer months up north. During the fasting periods, in Hawaii, they survive on their blubber. They mix their diet with copepods, euphausiids (krill), and small fish, primarily herring and capelin. They are considered filter feeders, using baleen plates to filter out their food. They take huge amounts of water into their mouth using a gulping method and then when they push the water out, they put their tongue up so the water must pass through the baleens. The food becomes trapped and falls toward the rear of the mouth. The two gulping methods hump-back whales use are lunge feeding and bubble net feeding. Lunge feeding is used when food is abundant. The whale simply swims through the prey with it's mouth open engulfing the prey. They can do this vertically, laterally or inverted. This is done toward the surface of the ocean. Bubble net feeding is used when the prey is less abundant. The whale dives below the prey and discharges bubbles from it's blowhole. As the bubbles