Cabrillo Marine Aquarium
 
 
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Ask a Biologist

 
  Why do grunion lay their eggs in the sand?  What is bioluminescence?  What is the health of our local abalone population?  Have questions?  Ask a Biologist!

Complete the form below to ask your question, which will be directed to one of our Aquarium scientists.  Then, check back often because selected questions and answers will be posted regularly.

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Question: We found rocks near your shoreline tidepools that have various holes in them. We are trying to figure out what created these holes.

Answer: Most of the holes in the rocks you find at the Cabrillo Beach tidepools are made by boring clams. There are a couple different species: pea-pod borers, date clams and the most common, piddocks. These all start to bore their holes as newly settled larva and slowly create an excavation they are literally entombed in. As normal erosion takes place, the rocks break apart and we all see the cool holes.



Question: What type of whale fossils have been found locally and what is their estimated age?

Answer: Whale fossils are found quite commonly in the tidepools and cliffs of Palos Verdes Peninsula in Southern California. We have many fossilized whale parts on public display at Cabrillo Marine Aquarium including vertebrae, skulls and even baleen. In general, most of our fossils are believed to about 15 million years old from the Miocene epoch.



Question: How do fish adjust their buoyancy?

Answer: Most fish have a swim bladder filled with air to adjust their bouyancy. Our exhibit on fish here at CMA explains the details of how the swim bladder works, but basically, fish can add or remove air from the swim bladder through a structure called the rete mirabilis. The process of adding or removing air from the swim bladder is a slow one which explains why some rockfish hauled up from deepwater can have their swim bladder so expanded that it sticks out of their mouths. Some very deepwater living fish lack a swimbladder and adjust their bouyancy by having their bodies less bony and more gelatinous (low specific gravity).



Question: Are you from this area? If so, do you remember the sand crabs that would bury themselves into the sand as the waves came and went? Bright orange eggs. What happened to them? Do they exist on beaches somewhere else? I have not seem them for at least 40 years.

Answer: Yes, Cabrillo Marine Aquarium is located at Cabrillo Beach which is the southwestern edge of the Port of Los Angeles. There are sand crabs at Cabrillo Beach, in fact, three different species. The one you are referring to is probably the most common sand crab Emerita analoga sometimes called a mole crab. They tend to migrate to subtidal (deeper) waters in the winter but can be very abundant on some beaches late spring to fall. Staff at CMA see them reliably at the far eastern end of Cabrillo Beach as the foot of the groin.



Question: I am taking a Marine Biology Honors course at my school and I am very interested in this field. I am concerned about how well our local area is going to withstand an El Nino event. Do you think the warmer temperatures brought by the El Nino would cause kelp to not grow or grow in less quantities?

Answer: Kelp (Macrocystis pyrifera) growth can be limited in El Nino years. El Nino is a natural event where warm ocean surface water can hug the coast of Southern California limiting the natural occurrence of upwelling. Upwelling brings cold, nutrient-rich water to the Southern California coastline and contributes to a very productive marine ecosystem including the growth of kelp. It is typical that kelp beds do diminish in size in El Nino years. However, it is also natural that kelp beds increase in size between El Nino years. It has been shown that impact by human activities (like stormwater runoff filled with particulates that decrease water clarity) has had an effect on kelp growth off the PV Peninsula (slow decline over the past 40 years, but lately stable). Kelp beds have shown an amazing resiliency over time for dying back in bad years (strong storms, El Nino) and growing back in years where conditions promote growth (cold, nutrient rich seawater with mild weather).



Question: I am doing a project on how the pollution caused by the Port of La affects marine ecosystems / marine animals. I am wondering what kind of ecosystems are around the Port of LA area. So far I have the Salt Marsh and the Kelp Forest. Is there a website or any other sources you recommend?

Answer: Two other nearshore major marine ecosystems would be sandy beaches (protected and wave swept) and rocky shores (including tidepools). There are two other habitats you can research, breakwater, open ocean and Channel Islands. You can look these habitats up on our website or better yet, visit CMA where we have exhibits detailing the animals and plants that live in these habitats.



Question: I want to grow kelp for my science project. (life cycle, and reforistation) Is there a website that could teach me how to grow kelp? Is there some place (in Illinois) I can donate the young plant after my science project is done? (to contribute to the reforistation project)

Answer: Thank you for your interest in the ocean even though you don't live near it! There are quite a few groups that grow kelp (Macrocystis pyrifera) on the CA coast. Most projects that I'm aware of are pretty small and have education and public outreach as the major goal with reforestation as a secondary goal. Some of these projects have succeeded in increasing the size of local area kelp forests. The links below will give you the contacts you need: California Coastkeeper Alliance, CA - Group that works to restore kelp forest habitat http://www.cacoastkeeper.org/programs/healthy-marine-habitats/kelp-restoration Santa Monica Bay Keeper, Santa Monica, CA - Kelp restoration program http://smbaykeeper.org/kelp.html Pacifica High School, Garden Grove, CA - Students grow kelp and contribute to reforestation efforts. http://www.kids4kelp.net/index.php



Question: How many salt marshes are left in Los Angeles County?

Answer: We have an exhibit that includes a map of the historic saltmarsh area in LA and Orange Counties. The number of saltmarshes left in LA County (4 main areas remain) belies the more important metric of how many acres remain from the original saltmarshes before development in the late 1800's in LA/Orange Counties. Before 1900 there were about 50,000 acres of saltmarshes and today there are less than 11,000 acres.



Question: What gasses make up the contents of the kelp floatation bulbs ?

Answer: Giant kelp (Macrocystis pyrifera) floatation bulbs (pneumatocysts) are filled with a variety of gasses (mostly nitrogen and oxygen) but includes about 10% carbon monoxide, the same toxic gas given off by car exhaust.



Question: If I have a pet crayfish and her eggs have just hatched, what can I do with all her babies?

Answer: We don't have much experience with freshwater animals here at Cabrillo Marine Aquarium. We only have ocean animals from Southern California waters. Here is a website that might give you some good information on how to care for your baby crayfish. http://lawrencehallofscience.org/foss/fossweb/teachers/materials/plantanimal/crayfish.html You can search the internet for "crayfish eggs" to get more sites with helpful information. You need to know that the mother crayfish may eat the babies and that some of the babies may eat each other. That is nature's way. If you keep them fed you can limit the amount of cannabalism. Good luck!



Question: I have a couple of pictures of what appears to be a mutant stingray. I caught it in Long Beach next to White Island. I was able to snap a couple of pictures, before the line broke and it went on its way. Iím very interested to know what it is we caught.

Answer: CMA's shark and ray expert thinks it is a longnose skate (Raja rhina). The snout (rostrum) is pretty long and the sides of the anterior disc is concave. These are reported as common in trawl catches from Point Loma to Alaska. They probably aren't caught by fisherman very often unless the bait is on the bottom. They reach a length of 4.5 feet.



Question: What are the brown shore birds hanging out with the gulls at Cabrillo Beach? They are not juvenile gulls, they don't spots, and have short reddish orange beaks. They are kind of gull-shaped, a little smaller than gulls.

Answer: The bird you describe sounds like a juvenile Heermann's gull (the red beak is characteristic and you probably noticed that the tip was black). These gulls occur on the west coast of North America from Alaska down into Baja California and are common to Cabrillo Beach. Adult Heermann's gulls are unusual in that their upper body feathers are dark gray, their underparts are light gray and only their head is white



Question: What do snails eat?

Answer: Most snails eat algae using a radula, a tongue-like set of teeth that scrapes the algae. Some snails are predators and files through clam shells, while others are scavengers.



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