Humpback Whale Migration Update: March 28, 2001 Today's Report Includes: Silver Bank- A Gem in the Caribbean For Humpbacks Whalewatching: Do's and Don'ts Why have these regulations and guidelines? Challenge Question #12 Discussion of CQ #11: Why Whales Scatter in the Summer Challenge Question #13 Holy Cow That's a Lot of Milk! Challenge Question #14 Try This! Got Milk? Silver Bank- A Gem in the Caribbean For Humpbacks Imagine basking in the warm and protected waters of the Caribbean this unusually cold winter of 2000-2001! Those humpbacks really know how to pick a safe and comfortable wintering grounds! The Silver Bank is a sub-marine platform located some 80 miles north of the Samana Peninsula and is part of the bank network from the Bahamas through the Christmas Bank. Protected from the strong waves and winds by a reef that even is dangerous for navigation, it creates the right environment for the reproduction and raising of baby humpbacks (world's largest concentration of humpback whales). The coral groups forming the reef have always been a challenge for navigation. In fact, the bank gets its name from an important ship wreck from 1641. That year, a ship loaded with gold and silver from Mexico was wrecked here on its way to Spain -- hence the name Silverbanks. This important calving ground for the humpbacks must remain safe for these endangered animals. With the rise in eco-tourism (a term for tourists seeking ecological-based vacation experiences) whalewatching has become increasingly popular in the Dominican Republic and in the feeding grounds of the north. Whalewatching: Do's and Don'ts Migration Route of Atlantic Humpback Whales Map courtesy of MacalesterCollege Down in Samana Bay in the Dominican Republic, a group of industry, government and non-governmental organizations, developed a plan (in 1994) which called for specific regulations for whalewatching: Whalewatching required a permit (private boaters could not go out purposely to watch whales, they could only cross the Bay on their way to a destination). When a whale was spotted, only one large (greater than 30 feet) and two small (between 18-30 feet)boats could approach only as close as 270 feet (80 meters) to a group including a mother-calf pair, or to within 165 feet (50 meters) of a group of other whales. When watching, boats are to put their engines in neutral and there is a 30-minute time limit for watching a group of whales. Boats awaiting their turns must stay at least 1,500 feet (500 meters) away from the whales. In the area with the greatest concentration of whales the speed limit was set at 5 knots. In the Gulf of Maine whalewatching vessels have been following a set of guidelines that were developed several years ago but have been under scrutiny lately. Here, the guidelines recommend that: A single boat can approach to 100 feet of a humpback whale, but all others must stand back at least 300 feet until it is their turn. Boats should approach stationary whales with no more than idle or "no wake" speed, and should not attempt a head-on approach to moving or resting whales. Boats should move parallel to the course of the moving whale. Vessels should limit their time to 15 minutes in close approach to whales. (Strict regulations for right whales prohibit approaches closer than 500 yards.) Why have these Regulations and Guidelines? Courtesy of Tomas L. Conlin. The main reason is to prevent harassment of the whales. If the whales were to become disturbed by too many competing boats approaching too closely, they might not get enough food to eat (up north) or might not be able to mate successfully (down south). Mothers and calves might get separated with drastic consequences. Boats moving too quickly in areas of high whale concentrations might inadvertently hit whales that are surfacing to breathe. Noisy, close approaches might also wake up resting whales or interfere with communication between whales. Here's this week's Challenge Question. We talked about boat speeds in this weeks report: Challenge Question #12 "For those of you with a love of nautical terminology, what is a knot?" (To respond to this question, please follow the instructions below.) Discussion of Challenge Question #11: Why Whales Scatter in Summer Last update we asked you to consider why the whales of Silver Bank would leave in many different directions after leaving the wintering grounds. You may have guessed that once those whales start to get serious about that BIG hunger they feel after many months without food in the wintering grounds, they look for a huge food supply. A whale eats a lot of food! The whales return each year to the feeding ground they came from where they will be sure to find enough food. If they all went to the same feeding ground there just wouldn't be enough food to go around. Thanks to students at Iselin Middle school for their great answers. Did you know that one of the favorite foods of humpbacks is a small, shrimp-like animal called a krill. Whales need to eat a lot of krill and other small fish to survive. That brings us to a research question: Challenge Question #13 "Whales are big animals. About how much food does a humpback whale consume each day at their summer feeding grounds?" (To respond to this question, please follow the instructions below.) Holy Cow That's a Lot of Milk! At birth, a baby humpback, or calf is able to move about on its own. The first hours and days of a calf's life are spent in close proximity with its mother. The mother bonds quickly with the calf and will provide food for the first nine to twelve months of its life. Whales' milk is thicker than milk of land mammals. It has less water (40-50% verses 80-90 % water). It also contains much more fat (40-50% compared with 2-17%) and about twice as much protein. A mother produces approximately 100- 130 gallons of milk a day. This highly concentrated milk will nourish a calf so it can grow up to a foot a month. The humpback newborn, approximately 12 feet in length and weighing nearly two tons, will double its overall length within a year. Challenge Question #14 "If a humpback calf consumes 130 gallons of milk each day for 9 months, what is the total amount of milk that the mother produces for the calf during that time?" (To respond to this question, please follow the instructions below.) Try This! Can you visualize 100 to130 gallons of milk a day? Here is a fun way to get a grasp of the quantity of milk a 12-foot newborn calf needs to grow a foot per month. Link to Got Milk? How to Respond to Today's Challenge Question: IMPORTANT: Answer only ONE question in each e-mail message. 1. Address an e-mail message to: jn-challenge-hwhale@learner.org 2. In the Subject Line of your message write: Challenge Question 12 (or #13, or #14). 3. In the body of your message, answer the question above. The Next Humpback Whale Migration Update will Be Posted on April 11, 2001. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form