California spiny lobster
California Spiny Lobster
All creatures in the animal kingdom can be scientifically classified with various groups and names. The California Spiny Lobster is a member of the Arthropada phylum. This phylum includes insects, spiders, centipedes, and other creatures. This explains why many people refer to lobsters as “bugs.” Lobsters are part of the Crustacea class which also includes shrimp, crabs, as well as other lobsters. The scientific name of the California Spiny Lobster is Panulirus interrupus. This means that it is a member of the Panulirus genus and its specific species is interrupus.
The California Spiny Lobster is found from the bottom tip of Baja California up to as far north as Monterey Bay, California. The lobsters are generally found at very shallow depths near the coastline of their habitat and near the offshore islands. The lobster migrate around during different parts of the year to mate, and to give birth to their young. During the spring, the lobster travel to shallow waters and then move to deeper waters in the fall. In December the lobster often move even more off shore to deeper waters, as deep as 110 feet. By late January, the lobsters generally move back up to depths between 15 and 45 feet of water.
The California Spiny Lobster is generally a nocturnal animal, meaning it sleeps during the day, and hunts for food at night. During the day time, lobsters can be found in small holes and cracks, or hidden in grass with other lobsters, but at night, they tend to hunt by themselves. Lobsters are scavengers who mainly eat non-moving, or slow moving animals. The foods that lobsters most often dine on are snails, sea urchins, clams, sponges, kelp, worms, mussels, scallops, barnacles, and fish. Sometimes they eat other, smaller lobsters. The lobsters are a vital part of the California coast habitat because they keep the purple and red sea urchin population under control. The jaws of the California Spiny Lobster are extremely strong, and they are capable of crushing shells and bones of other animals with a loud crunch.
The body or exoskeleton structure of the California Spiny Lobster is composed of two main parts. These two parts are the carapace and the tail. The carapace is the main body of the lobster. All the legs stem off of the carapace and the top of it has the spines. The antennae, horn, and antennules also branch off the front of the carapace. The spiny lobster has ten legs, and each leg has tiny hairs which can sense chemical and temperature changes.
The other major part of the lobsters body is the tail. The tail is mainly used for propulsion through the water. Located under the tail are the swimmerets, or pleopods. The female lobsters have large swimmerets where they keep the fertilized eggs during some parts of the year.
One of the most noticeable features of the spiny lobster is the two large antennae. The antennae are longer than the body, and they are used to sense any movement in front of them. Lobsters also have smaller antennae called antennules, which are used to sense food and predators.
The lobsters outer shell is called the exoskeleton. The exoskeleton is very hard and they cannot grow while wearing it, so lobsters have to grow by shedding their shell, and creating a new one for their enlarged body. This form of growth is called molting. When the lobster molts, it hides in a safe places, and it usually doesn’t eat for a while. Before the lobster actually leaves its original shell, it grows another much softer shell under its current one. Next, the lobster will pull the calcium, which keeps the shells hard, out of the original shell and stores it in its blood stream until it is needed to harden the new shell. Taking the calcium out of the original shell also makes it softer and easier to slip out of. Once the lobster is out of the old shell, it pumps water into its cells which causes it to grow bigger. After the lobster has grown, it pumps the calcium back into the shell and waits for it to harden. At this point the lobster needs to go out and eat a lot of food to collect more calcium, and because it doesn’t eat during the molting process.
Adult lobsters will generally start molting after they complete the reproductive cycle in the months of August through October, and they only molt about once a year. Juvenile lobsters molt 25 times in their first five to seven years. After that time, the lobster has grown to about one pound, and they have reached the age of sexual maturity.
The lobsters are prey for many different animals. Their main predators are giant sea bass, kelp bass, California sheephead, California scorpionfish, rockfishes, octopus, California moray eels, sea otters, cabezon, horn sharks, leopard sharks, other lobster, and humans.
California Spiny Lobsters do not have large claws like some other lobster species do, but they do have other defense mechanisms to keep them safe. One protection that the lobsters have is the abundant spines on their backs. The two largest spines located over their eyes are know as the horns. If a predator turns out to be a real threat, lobsters have very powerful tails with can trust them rapidly through the water with quick bursts to safety.
Like many other animals, lobsters reproduce sexually. The lobsters tend to mate between January and April. When the lobsters meet, the male will mount the female and swing her over so they are facing belly to belly. Once they are in position he quickly deposits his sperm into a packet on the female’s belly. After this is over the lobsters both separate and go back to trying to survive.
When the female lobster is ready, she will scratch open the sperm packet with the specialized claws on her back feet while simultaneously releasing her eggs from a hole on her belly. Then when the sperm fertilizes the egg, it will stick to the underside of the swimmerets and stay there until it is hatched. The eggs that don’t get fertilized do not stick and float off into the open water. A newly matured female will produce about 100,000 eggs while an older and larger female will make nearly 1,000,000.
When the female lobster is ready to release the fertilized eggs she goes to shallower, warmer water, usually in May or June. The eggs start as a brightly colored red when they are first fertilized, but after about ten weeks they turn to a dark brown.
Once the lobster young hatch they look completely different from what fully grown lobster look like. The lobster young are called phyllosoma larvae. They are free floating creatures with very little mobility. As they float around, they are predators of other drifting planktonic plants and animals. After about six to nine months, when the larvae has molted 12 times, it would have grown into the next stage of life called the puerulus meaning child. This looks like a small lobster with very large antennae. The puerulus moves very close to shore where it molts into a juvenile lobster.
Back in the days before divers went down to pick lobsters by hand, lobsters often grew to be 150 years old and over three feet long. These giant lobsters were too big to fit into any traps, and had very few predators. Most lobsters now grow to the age of five to seven years before being picked. This is the age where they reach sexual maturity, and have grown to the legal size to be caught.
In southern California, lobster hunting is a huge business because there is such a high demand for lobster. Most commercial fishermen use lobster traps because they have many advantages over other collection techniques. Lobster traps are rectangular shaped boxes made out of wire mesh coated with tar. All traps must have a 2-3/8 x 11-1/2 inch escape hole so the illegal sized lobsters can get out. Every trap must also have a destruction device which allows the door to fall open after the trap has been out too long. The traps are sunk to the bottom with weights where they are baited with dead fish or cat food. Coming up from every trap if a buoy that has the letter P followed by the license number of the fisherman who set it.
Unlike recreational fishermen, commercial fishermen are not limited by the seven lobster per day limit. They do have to follow the rule that each lobster must be 3-1/4 inches from the eye socket to the edge of the carapice. They also may only fish during the lobster season which starts on the Saturday preceding the first Wednesday in October through the first Wednesday after the 15th of March. All commercial fishermen must also keep a log of the exact number of legal and illegal lobster they catch.
The lobster traps have some advantages and some disadvantages over SCUBA diving and picking the lobster by hand. One advantage of using traps is that a fisherman with one boat can set, pull, and reset over 100 traps in one day, making it much more efficient that doing a few dives looking for lobster. With that many traps out, a fisherman could collect anywhere from 100 lobster to 1000 lobster. Lastly, the traps are not held back by the constraints of SCUBA such as depth, underwater time, or water conditions.
The California Spiny Lobster is a very unique and interesting animal. It is vital to the environment and the food web and plays a significant role in the West Coast economy.
Report by Matt Grenewetzki and Nikki Armstrong