The Great Spring Skate & Whelk Egg Case Hunt!
Become a community scientist this spring (March, April & May) by helping Save Coastal Wildlife Nonprofit find and record Skate or Whelk egg cases!
Skate identification above is from Assateague Island National Seashore.
WE NEED YOUR HELP!
Populations of various species of skates and whelks along the Jersey Shore are largely unknown at best and decreasing at worst.
Please help Save Coastal Wildlife Nonprofit by recording your find of a skate or whelk egg case along the Jersey Shore. Empty egg cases can help indicate species presence and diversity in nearby waters. By recording your finds, you're helping us to discover more about egg-laying species in our waters. Empty egg cases from skates, whelks, and even sharks can help indicate species presence and diversity along the Jersey Shore.
Unfortunately, it doesn’t take much time or effort for an animal to become threatened or endangered. Once it does, it can take decades or more for a species to recover, if ever. One of best times to start protecting an animal is when threats are known. Waiting until a specie’s population is dwindling might be too late. Since many species of skates found along the Jersey Shore are commercially unimportant, their true conservation status is poorly known.
All volunteers with Save Coastal Wildlife nonprofit are required to fill out the volunteer waiver form before starting a citizen science project.
A Knobbed Whelk (Busycon carica) Egg Case. Picture from Kimberly at Assateague State Park in Maryland.
How to Record Your Egg Case!
Congratulations! You found an egg case! So how do you identify and record your find. First off you will have to prepare your egg case to be identified. At home, please prepare your egg case by rehydrating it. This makes an egg case easier to identify. An egg case truly belongs in the water, not dried out on a beach from the sun and wind. You’ll see how much a skate egg case expands to its true size.
Little Skate egg case
Step 1: Fill a container with tap water.
Step 2: Put the egg case in the water – if possible try to remove all the air so it sinks.
Step 3: Leave in the water to soak for 1 to 6 hours - the longer it’s been out of water, the longer it will need to be in the water.
Step 4: Remove the egg case from the water & start identifying your find (see below).
Step 5: Record your egg case find with Save Coastal Wildlife Nonprofit (click button below)
*THREATS TO SKATES & WHELKS*
Skates are a type of fish that are closely related to the rays and more distantly related to sharks. The skates are the most diverse lineage of the cartilaginous fishes (sharks, skates, and rays). The term ‘cartilaginous fishes’ refers to the fact that these groups do not have true bone and instead have skeletons made of hardened cartilage.
The skates are under constant threat along the northwestern Atlantic Ocean as bycatch from commercial fisheries with bottom trawling nets used to target other species of fish. Skates, like sharks and rays, are slow growing and late to mature, produce few young, and may not reproduce every year, plus they are bottom feeders particularly at night. All this makes skates especially vulnerable to a population decline from bycatch.
For example…
During the 1960s and 1970s, barndoor skates (Dipturus laevis) were depleted by commercial fisheries as bycatch. Bottom fisheries that targeted Atlantic cod and other species accidentally captured a large number of barndoor skates. This caused numbers to drop quickly. Conservation efforts that began in the 1990s have succeeded in increasing numbers, but scientists still consider this species to be endangered.
Whelks, a type of mollusk and sea snail, are increasingly under threat and in demand by local commercial fishermen for overseas markets in Europe and Asia. If you ever had a plate of scungilli, then you were eating a whelk. Commercial fisheries are putting pressure on populations of this sea snail at a localized risk of collapse along the Jersey Shore. The annual dockside value of the whelk catch now tops $1 million in Virginia and Rhode Island, $1.4 million in New Jersey and $5.7 million in Massachusetts, according to marine fishery agencies in those states. In Delaware, knobbed and channeled whelks are now the third most valuable fishery behind blue crabs and striped bass.
These threats from commercial fishing may be causing the distribution of different skate and whelk species to change along the Jersey Shore, and population numbers for certain species may be weakened.
By taking part in the Great Spring Skate & Whelk Egg Case Hunt you are helping Save Coastal Wildlife nonprofit to identify problems early. Egg cases may indicate that nursery grounds are nearby and can assist in the conservation of skates and whelks. Your egg case records are a crucial element of local conservation.
What’s an egg case?
All skates and whelks reproduce by laying egg cases. Skates lay black leather pouches often called mermaid purses. Whelks lay yellowish-tan rounded egg capsules joined to form a chain that is sometimes called a mermaid’s necklace.
For the skates, their egg cases are surrounded by a tough leathery capsule that protects the embryo as it develops inside. After several months these are ready to hatch, and a fully-formed skate will emerge. Skates lay egg cases, all rays give birth to live young. Some species of sharks also lay egg cases, while others give birth to live young. Once empty, the eggcases (or mermaid’s purses) often wash up on the beach.
For whelks, mating and egg laying occur during the spring and fall migration. Internally fertilized eggs are laid in a protective flat, rounded egg capsules joined to form a paper-like chain of egg cases, commonly called a "Mermaid's Necklace". Some people also describe them as a stack of small crackers that are coiled together in an accordion-like belt. On average each capsule contains 1-99 eggs, with most strings having 40-160 capsules. After laying their egg cases, female whelks will bury one end of the egg case into the substrate, thus providing an anchor for the developing fertilized eggs and preventing the string of egg cases from washing ashore where it would dehydrate. Fertilized eggs develop in the capsules.
Where can I find an Egg Case?
During low tide and after a storm are some of the best times to look for egg cases on a coastal beach. One of the best places to find an egg case on a coastal beach is among the strand-line or tide-line, where seaweed, debris and remains of dead life washes up. The egg cases of different species vary. So, by looking at the size, shape and features, we can tell which species laid it. You can learn to identify eggcases too. We’ll show you how!
Skate egg case
Whelk egg case
Of course, egg cases may wash up all year-round. It just doesn’t have to be in the spring to look and record your egg case finds on the beach.
Why not have fun beach-combing all year long to see how many egg cases you can find?
How do I identify a Skate Egg Case?
Above image of a Clearnose skate and its egg case. Image from Fishes of the Western Atlantic, Sawfishes, Guitarfishes, Skates, Rays Chimaeroids, by Henry B. Bigelow and William C. Schroeder, originally published in 1953 by Sears Foundation for Marine Research, Yale University.
All skate egg cases are made out of the fibrous protein collagen which forms tough leathery pouches. Almost all egg cases contain a single egg, although some species of skates around the world can contain up to seven. After the cases are released from the mother they provide the embryo with all the nutrients and energy it needs to develop, including oxygen-rich seawater which can be taken in by the horns of the case. Development usually only takes a few months for most species. Once the babies have reached a point where they can survive on their own without their purses they swim out of a small opening at the top of the case and leave their former home behind.
Clearnose Skate (Raja eglanteria): The egg case, which usually black in color, ranges in size from 2 - 3.5 inches long (without the horns), and 1.5 to 2.2 inches wide. The horns are almost always shorter than the egg case itself. Egg cases farther south, such as in Florida, are generally smaller than those found in New Jersey, New York and Massachusetts. Incubation of the baby skate inside is normally a period of three months, but it could vary. There is still much we do not know about the skate incubation period.
Above image of a Little Skate egg case. Image from Fishes of the Western Atlantic, Sawfishes, Guitarfishes, Skates, Rays Chimaeroids, by Henry B. Bigelow and William C. Schroeder, originally published in 1953 by Sears Foundation for Marine Research, Yale University.
Little Skate (Leucoraja erinacea): The color of the egg case is amber or golden yellow when laid, but are usually black when found empty. The average size ranges from 2.1 -2.4 inches long (excluding the horns) by 1.3 - 1.7 inches wide. One side of the egg case will have a longer pair of horns. The horns of both sides will taper to slender tips, so fragile that they ordinarily break apart when found. The longer horns are nearly straight, the shorter pair more or less curved, one toward the other.
Winter Skate (Leucoraja ocellata): The color of the egg case varies from black-gray to greenish brown or brownish olive. Sizes range from 2.1 - 3.8 inches long by 1.3 - 2.0 inches wide, excluding the horns. Northern egg cases average larger than southern egg cases. One end of the egg case has shorter horns that are usually concave. The side with the longer horns are usually straight to somewhat bending. The longer horns are normally 1.5 times as long as the shorter pair, and about 1.5 times as long as the egg case, but the tips are fragile and generally have broken off when found.
Additional egg cases from species of skates. Egg cases from barndoor skates (Dipturus laevis) and thorny skates (Amblyraja radiata) are rare finds along the Jersey Shore.
Egg cases of the barndoor skate (left) the thorny skate (middle) and the winter skate (right). Picture from Semantic Scholar.
How do I identify a Whelk Egg Case?
How do I identify a Whelk Egg Case?
All whelks in New Jersey lay their eggs in a long, spiral-shaped casing that can reach up to 33 inches in length. The strand contains up to 200 small pouches, and each pouch contains up to 99 eggs. The female protects the string of eggs by anchoring one end at the bottom of the bay or ocean. This prevents the egg case from washing ashore and drying out in the sun. Eventually a whelk egg case will break free from the sand. This is why you might come across one on the beach now and then.
Knobbed Whelk (Busycon carica): Adults lay their distinctive egg cases near the low tide line. Their eggs may be described as a stack of checkers with jagged, somewhat squared-off edges in an accordion-like belt.
Knobbed Whelk Egg Case
Channel Whelk (Busycotypus canaliculatus): Adults lay eggs in the intertidal to the shallow sub-tidal depths. Egg cases resemble stack of miniature compact discs (with thin edges) in an accordion-like belt.
A break in the channel whelk egg case where the young whelks exit
