Boston — What a way to start the work day: weighing herring tidbits and getting wet dolphin kisses.
But this is just part of the daily drill at the New England Aquarium for two dolphin and seal trainers, Sue Sinclair and Janet Hester.
The two animal lovers started out by volunteering at the aquarium in their free time. Gradually they worked up to full-time trainers on The Discovery, the floating theater alongside the aquarium where these sea mammals perform daily.
The first big discovery for Sue, who is now head trainer, and for Janet was that these animals have distinct identities. ''Each one is different,'' Sue says, ''and you have to deal with them as the individuals they are. That keeps you very interested in what you are doing.''
To the audience, dolphins appear to be a pool full of identical twins. ''They just look like big gray globs unless you have had experience with them,'' she explains. ''But if you were here for only an afternoon, probably by the end of the day you would notice their different characteristics. They really do look different.''
During the 40-minute show, while patting one of the three dolphin stars on the snout, she tells the audience what a dolphin feels like. All slimy or scaly? Not a bit of it, she says. ''Their skin is very smooth and feels like a wet inner tube or a hard-boiled egg.''
A seal act gets the show going and is followed by a short educational film on sea mammals in the wild.
The dolphin part of the program begins when three Atlantic bottlenosed dolphins swim through the underwater door leading from their retaining pool backstage into the performing pool. Cathy, a 550-pound teen-ager (17 years old) , Dixie, a temperamental, 450-pound nine-year-old, and Carol, an eight-year-old 400-pounder, nuzzle their faces over the edge of the stage at Sue's feet, awaiting their cue.
When she says, ''Shall we start by saying hello to everybody?'' the trio let loose with high-pitched, ear-splitting yakety-yak-yak squeaks that evoke delighted squeals from the audience of schoolchildren.
Dolphins are noisemakers. But their raucous sounds - and they have a big vocabulary of them - emanate not from their mouths but from the blowhole in the top of their heads.
On this particular morning Dixie, the show's unpredictable prima donna, seems to have gotten up on the wrong side of the pool. Instead of obediently beaching herself on stage for a few moments so that everybody can see how beautiful a bottlenosed dolphin is, she is doing what she often does in the morning - skulking on the bottom of the pool, testing her trainer to see how much she can get away with.
Normally a quick learner and hard worker, she performs some of the most spectacular tricks - ''behaviors,'' as the trainers call them - such as hurtling up out of the water at high speed to hit a red ball hanging 20 feet above the pool. Even with four or five performances a day, she misses only about once a month. But when Dixie doesn't want to perform, she sometimes tries to prevent her colleagues from doing their thing.
''Dixie!'' Sue reproaches, ''you are a mammal. You have to come up for air at some point. Do you think you're ready to do this yet?'' No, Dixie is not. She cruises by the stage, glowering at Sue. Suddenly she changes her mind, shifts gears, and zooms onto the stage on her stomach with her tail riding high as if serving herself on a platter.
This is an impressive accomplishment for both trainer and trainee, because it is not normal for a dolphin to come up out of the water unless it is not feeling well and drifts up onto a beach. Most of the time, 90 percent of a dolphin is under water. So this behavior gives the audience a rare, fleeting look at the symmetry of the whole animal.
Cooperation is not necessarily a dolphin's middle name. Some days these performers behave like the great star Garbo. They just ''vant to be alone.'' One may hang around the side of the pool while another sticks around the stage. Then they'll trade places. They just don't want to be in the same place at the same time.
But when they want to work together, they are masters of synchronized action. In the ocean, bottlenosed dolphins travel in large groups so that doing things together comes naturally to them.
''If you give a signal to three dolphins to do bows at the beginning of a program,'' Janet says, ''it apparently is just their natural tendency to move together, because that is not something that we have ever had to train.''
In the show these hefty mammals stand bolt upright on their tails, then do forward flips and fantastic jumps through hoops and over hurdles, all with marvelous, synchronized grace. ''They make us look terrific!'' Janet says, laughing. ''But they deserve most of the credit.''
Their training is done with buckets and buckets of fish - and mountains of patience on the part of trainers. If the behavior is simple enough, it may be learned in 15 minutes. But something complicated or strenuous, such as the forward flip, took Carol seven months to learn. Usually a dolphin or sea lion is in training for a year before joining the show.
The aquarium's basic teaching method is the food reward system, whose technical term is operant conditioning. ''If an animal gives a correct response ,'' Sue explains, ''we give him some food for what he has done. That is, we positively reinforce him for doing something correctly. And we ignore incorrect responses, so that he will give us the correct response more often than the incorrect one, because something good happens to him after he gives us the right response.''
Something the public worries about, Janet says, ''is whether they are ever punished. The most severe kind of negative reinforcement we use is merely ignoring them. There is no physical abuse by any means. That is no way to train an animal.''
Food is never withheld from a slow learner, Janet says. ''Though we are here to educate and entertain the public, our first consideration is the health of the animals.''
During the shows, dolphins and sea lions may eat up to 9 percent of their daily ration. But regardless of their performance or lack of performance, they ''are never fed less than the amount of food we feel they need to receive during the day,'' Sue stresses. ''We take an animal's age, weight, and growth rate into account, then decide what it needs to maintain a healthy growth rate.''
A concerned public may also wonder if the extraordinary tricks these mammals perform are thought up by some showman and forced on them. Actually, it is just the reverse. The actions that bring thunderous applause from audiences are polished versions of the kind of natural play for which dolphins have been admired for centuries.
''These are behaviors the animals have started out on their own,'' Sue says. ''We just take what they give us and shape it into the finished product. They can come up with pretty fantastic things on their own if you give them an opportunity.''
So one type of training done here is called ''innovative training sessions.'' ''We take a bucket of fish out there to the show pool,'' she says, ''stand back, and watch the things that the animals do.
''If they do something they have never been rewarded for before, we blow our whistle and reward them for it. . . . If we only reward them for doing each thing one time, sometimes they do the most outrageous things.''
For example, in training sessions completely separate from each other, both Dixie and Carol started doing horizontal spins, a behavior not natural for bottlenosed dolphins.
''It started out as a half turn,'' Sue recalls. ''They were rewarded for that, but not rewarded again for doing that half turn. Progressively, the turn developed into a complete revolution. Now the pair synchronize these horizontal spins in the show, with Dixie doing three revolutions in one jump.''
This is known as ''training by approximation.'' The trainer asks more and more of the animal each time, whether it is an additional revolution, more height, or whatever. ''You are asking for constant improvement,'' Janet says, ''until you reach the point where you consider it a completed behavior.'' From then on the trainer elicits these actions by a hand signal.
Dolphins are the smallest of the toothed whales. About 50 species have been identified. Some varieties are found only in the ocean deep. But the bottlenosed dolphin lives naturally in very shallow, temperate, coastal waters. So they adapt well to living in pools. This explains why the bottlenosed dolphin is the kind most often seen in aquariums, movies, and on TV.
It has excellent vision, acute hearing, and a sonar, or echo-location, system that scientists say is unequaled by space-age technology. They are not completely understood. But their ability to learn complicated behaviors suggests that they are among the more intelligent mammals, such as the chimpanzee.
One thing is certain, though. They have a private life backstage. The group has its own hierarchy, with age, experience, and size appearing to determine rank.The chief doesn't have to be a male. It could be a big, wise female.
Grown-up dolphins are like grown-up people in one sense - they treat their small fry with more tolerance than they show for animals their own age. But they mingle their forebearance with a certain disciplinary conduct to show who is boss.
''This is how it goes,'' says Janet: ''If you've got the beach ball and I want it, I am perfectly willing to give you a little pop with my tail so I can take it from you. You should learn that you had better stay away while I am playing, thank you.''
In the limelight all day, the performers take the night off, when nothing is asked of them from people. They rest for perhaps 10 or 15 minutes at a time. But they only sleep in short catnaps of a few seconds' duration, with one eye shut. For dolphins, breathing is a voluntary action requiring some effort. So they can't afford to sleep very long, because they might forget to breathe.
Are the aquarium's animals happy? Those big smiles on the dolphins certainly make them look happy. But who knows for sure? One sign that they and the sea lions are adapting well to their environment here is that in the last couple of years they have begun to bear young.
And one of the first and most basic lessons the baby dolphins learn is to swim through an underwater door into the show pool. Teaching them to do it is one of the more difficult tasks for their trainers.
''Apparently, it is a little frightening to go through an opening into an unknown space,'' Janet says. ''Even though the adult animals are quite used to doing it, they are not so eager to take their young with them. Every other night we open the door for Spit, our mother dolphin. But so far as we know, she has not taken her calf, Orion (born Feb. 22), out there yet.
''Here is another case where we work with the animal. We do not try to force the issue. When they are ready, we will take advantage of it.''
One of the behaviors the dolphins invented is tails up, heads down under. Just before their exit, Cathie, Carol, and Dixie line up in a row and wave their tails at their trainers and the audience.
''We thinkm it's a goodbye wave,'' Janet says, grinning, ''but we can't be sure. To me, it's like a little editorial comment."